Table of Content

15 November 2003, Volume 14 Issue 11

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Articles

Succession of Larix olgensis and Betula platyphlla-marsh ecotone communities in Changbai Mountain

MU Changcheng

2003, (11):  1813-1819. 

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The succession of communities within the ecotone between forest and marsh in Changbai Mountain was studied to identify the interrelation between the succession of ecotone communities and the mesophytization of the ecotone. The succession regime of the ecotone communities was studies by patch size (the volume of each mound) and age class of different tree species, water transmission from soil to atmosphere through the transpiration of different tree species, and regional climate warming and community succession. The results demonstrated that both patch size and water loss through transpiration were increased with age class. The increased volume of mounds and water loss through transpiration of trees were converted to the raised ground surface level and the lowered ground surface water level. Within60 years, the ground surface level would be raised by 0.405～0.590 m, depending on the distance to the marsh, and the aboveground water level would be lowered by 1.050～1.442 m. Climate had a great effect on the community dynamics. Community succession and regional climate warming intensified the mesophytization process of forest marsh ecotone, and the ecotone communities would eventually change into forest communities within a relatively short period.

Nutrient characteristics in leaves of broadleaved seedlings in south China

XUE Li, WEI Ruping, TAN Tianyong, KUANG Ligang, WEI Meiman

2003, (11):  1820-1824. 

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Nutrient concentrations and contents in leaves of broadleaved Elaeocarpus sylvestris,Castanopsis hystrix,Ormosia pinnata,Michelia macclurei,Camellia semiserata,Liquidambar formosana,Castanopsis fissa,Mytilaria laosensis and Cinnamomum camphora seedlings were studied. Leaf N,Pand Kconcentrations in Ormosia pinnata,Castanopsis fissa and Cinnamomum camphora were higher than those of other tree species,and leaf N,Pand Kcontents in Camellia semiserata,Castanopsis fissa and Cinnamomum camphora were higher than those of other tree species. Mean leaf nutrient concentration in upper crown and lower crown of 9 tree species was N 16.67 and 17.09 g穔g^-1,P1.29 and 0.84 g穔g^-1,K11.77 and 6.65 g穔g^-1,respectively. Mean leaf nutrient content in upper crown and lower crown of 9 tree species was N 0.871 and 1.069 g穖^-2,P0.065 and 0.052 g穖^-2,K0.608 and 0.426 g穖^-2,respectively. Leaf Pand Kconcentrations and contents in the upper crown were generally higher than those of the lower crown. From the view of nutrient contents,mixing Camellia semiserata with other tree species,mixing Castanopsis hystrix or Mytilaria laosensis with Elaeocarpus sylvestris,Liquidambar formosana,Ormosia pinnata,Castanopsis fissa,and Cinnamomum camphora,and mixing Michelia macclurei with Castanopsis fissa and Cinnamomum camphora were suitable.

Water storage characteristics of ground covers under three forests in Three Gorges Area

CHENG Jinhua, ZHANG Hongjiang, SHI Yuhu, CHENG Yun, QI Shenglin, HE Fan, PAN Lei

2003, (11):  1825-1828. 

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Through water holding experiments and the survey of ground covers under three forests (mixed forest of Quercus variabilis and Pinus massoniana, pure Quercus variabilis forest and pure Pinus massoniana forest) in Three Gorges Area, the hydrological characteristic parameters,e.g.,maximum water holding capacity and water absorption speed, were measured.The results showed that the maximum water holding capacity of moss under pure Quercus variabilis forest is the highest (303.1 % of its dry weight), that under mixed forest of Quercus variabilis and Pinus massoniana was 283.8 %,and that under pure Pinus massoniana forest was 242.3 %.The maximum water holding capacity of litter under mixed forest stand of Quercus variabils and Pinus massoniana was 282.2 % of its dry weight, that under pure Quercus variabilis forest is 262.5 %, that under pure Pinus massoniana forest was 239.3 %.The equation between water absorption speed of ground cover and its immersed period could be S=kt n.The results also showed that when the forests were all in mid-age, the water holding ability of the mosses was higher than that of the litters under the same forest.The ground cover's variation with its immersed period had no relation to forest types.

Ecological effects of bagging on actinidia fruits

CHEN Zhijie, ZHANG Shulian, ZNANG Feng, SHI Yongqiang

2003, (11):  1829-1832. 

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Studies on the ecological effects of bagging on actinidia fruits showed that under different types of bagging,the ecological effects on actinidia fruits were different.Bagging with membrane changed the conditions of temperature and humidity.The inside temperature raised by 0.7～0.9 ℃,humidity increased by 10.8%～11.8%,single fruit weight increased by 25.7%～37.7%,commercial fruit rate raised by 20.4%～30.1%,percentage of diseases and pests decreased by 85.7%～90.2%,and storage property was good.Additionally,the application rate of chemical pesticide was reduce by 72.2%,and the concentration of remnant pesticide inside fruits was only 0.31% mg·kg^-1,which was decreased by 90.0%.The chemical pesticide pollution in ecological circumstance and actinidia fruits both reduced.It would be a new way for the rgeen fruits production in the future.Bagging with paper has obvious negative effects.

Articles

Effects of light on carotenoid biosynthesis and color formation of citrus fruit peel

TAO Jun, ZHANG Shanglong, AN Xinmin, ZHAO Zhizhong

2003, (11):  1833-1836. 

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The effects of shading fruit with opaque paper bag at the late stage of fruit enlargement on the contents of chlorophyll, carotenoid and in “Hongshigan” citrus (C.reticulata × C.sinensis) fruit peel and its color were examined. The results showed that after shading,the chlorophyll content in peel decreased quickly, which resulted in its earlier color shifting. In contrast, the contents of total carotenoids and each carotenoid component did not increase,but decreased significantly. At the stage of fruit riping, both chlorophyll in shaded and unshaded fruit disappeared,and the shaded fruit,owing to its lower level of carotenoids, had a lighter color than the unshaded fruit. The sugar content in peel of shaded fruit did not differ obviously from that of unshaded fruit at the earlier stage, but dropped markedly at the late stage of shading. Removing the enclosing paper bag from shaded fruit at the late stage of shading resulted in the increase of sugar, and correspondingly in the increase of carotenoid, especially of β-cryptoxanthin accumulation with consequent darkening of fruit color.These results stressed the effect of light on stimulating carotenoid synthesis,especially the accumulation of β-cryptoxanthin in citrus fruit peel. The light is the enviromental signal essential for carotenoid synthesis in citrus fruit peel during certain stage of fruit development.

Semi-nested LP-PCR-SSCP identification of arbuscular endomycorrhizal fungi diversity of Alnus at Changbai Mountain

LI Yiye, HE Xingyuan, ZHANG Zhongze, ZHANG Chenggang

2003, (11):  1837-1841. 

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The diversity of arbuscular endomycorrhizal fungi colonized on three species of Alnus at Changbai Mountain was identified based on coupling the sensitivity of semi-nested LP-PCR and the specificity afforded by Single Strand Conformation Polymorphism analysis. It is suggested that altitudes and species of Alnus were not the important factors deciding the distribution of AMF in the grade of family, and there was at least one species of Glomaceae, Glomus intraradix, dominated in Alnus at Changbai Mountain.

Physiological response to salt-alkali stress in experimental populations in two ecotypes of Leymus chinensis in the Songnen Plains of China

ZHOU Chan, YANG Yunfei

2003, (11):  1842-1846. 

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The comparative study of physiological reaction to salt, alkali and mixed salt stresses in two ecotypes of grey-green and yellow-green of Leymus chinensis were made. At the stage of seedling, the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers were determined in planting containers with sands in two ecotypes by stress of salt, alkali and mixed salt of different concentrations. The results of quantitative analysis showed that the relationships between the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers and concentration of salt, alkali and mixed salt could expressed as linear equation, which were significant or obviously significant. There were capabilities of salt-alkali resistance in the physiological characteristics of two populations, but the capabilities of salt-alkali resistance were stronger in grey-green ecotype than in yellow-green ecotype. The differentiation of the content of chlorophyll, the leakage rate of electrolyte of leaves, free proline and Na/K of tillers were significant or obviously significant in two ecotypes under three kinds of salt stress. Physiological characteristics of salt-alkali resistance were significantly different in two ecotypes. The study provided physiological evidence for making sure that the main ecological factor was salt-alkali. It resulted in adaptive differentiation in Leymus chinensis ecotypes.

Module structure of Leymus chinensis clones under cultivated condition in Songnen Plains of China

YANG Yunfei, ZHANG Baotian, LI Jiandong

2003, (11):  1847-1850. 

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Leymus chinensis is a perennial rhizome grass, a species of typical clonal plant. In the Songnen Plains of China, the ramets of the clone consist of tillers and seedlings under cultivated condition during the last stage of growing season. The tillering nodes of the ramets could propagate four generations, with enough growing space and no interspecies competition in the sandy soil habitats during a growing season. According to the vegetative reproductive generations of tillering nodes, the age spectrum was the largest on the modules of the first age classes for present or potential clones, which reduced obviously with increasing age classes, and they were all expanding type on the age structure. The productivity of every ramet module correlated largely with the time length for growing and the formation of the ramets. The earlier formation time and the longer growing time, the greater the tillers contributed to material production and vegetative reproduction of the clone. There was a certain capability of adjustment for the spatial expansion and the material storage of the test clones.

Seed germination characteristics and regeneration mechanism of Stellera chamaejasme population

XING Fu, GUO Jixun, WANG Yanhong

2003, (11):  1851-1854. 

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Stellera chamaejasme is a perennial herbaceous plant of Thymelaceae, as one of major poisonous plant species to animal, distributing in Northeast, Northwest, and Southeast of China. In some area on the degraded steppes, the plant grew with abnormal abundance and badly endangered the health of animals. The germination capacity of Stellera chamaejasme seed that collected from soil seed bank and immediately gathered from the plant was studied under different temperature, light condition and five pretreatments (rupture seed pericarp, remove seed pericarp, soaked in 98% H₂SO₄ for 5 min, soaked in0.2 % KNO₃ for 24 h, and kept at 10℃ for a week). The seed germination percentage (GP) of the plant was lower in the mass and it was 13% under constant temperature 25℃ with dark condition. The suitable temperatures for germination of the seeds were constant 30℃ or alternative 10～30℃. To rupture or to remove seed pericarp could significantly increase GPand it was 49% and 47%, respectively. GPunder pretreatment of seed soaked in 98% H₂SO₄ for 5 min was 32%. The pretreatments of seed soaked in0.2 % KNO₃ for 24 h and seed kept at 10℃ for a week had no significantly effects on increasing GP. The seed germination was not sensitive to light condition. The hardness of the seeds was mainly responsible for the seed dormancy and low germination rate. The GP of S. chamaejasme seeds in the soil seed bank was higher than that gathered in the immediate year. Based on the comprehensive analysis with the lower GP and the results of field observation, it was concluded that S. chamaejasme seeds did not germinate every year in nature, and chance of population regeneration was random or periodic.

Contribution of fertilization development to yield production and its geographic differentiation

YU Wantai, ZHANG Lu, MA Qiang, YIN Xiuyan, SHEN Shanmin

2003, (11):  1855-1858. 

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The results of long-term field experiments at three stations in different areas of China indicated that the contribution of fertilization to crop yield was significantly affected by the thermal condition of climate and the fertilization system. In the case of optimum fertilization, the largest contribution rate was 0.31 (average of fourteen years) at Hailun Station (in temperate zone), 0.39 (average of twelve years) at Shenyang Station (in warmer-temperate zone), and 0.42 (average of eleven years) at Taoyuan Station (in subtropical zone), which showed that the existence of geographic differentiation was caused by the thermal condition of local climate. Therefore, keeping the optimum fertilization systems, the largest contribution rate to crop yield could be estimated from 30% to 50%, depending on the local climate condition. The interaction of fertilization and thermal factor between Shenyang and Taoyuan was much bigger than that between Shenyang and Hailun. The interaction between organic manure and thermal condition of local climate was bigger than that between chemical fertilizer and thermal condition of local climate.

Fate of fertilizer nitrogen in paddy field of black soil region

HAN Xiaozeng, WANG Shouyu, SONG Chunyu, QIAO Yunfa

2003, (11):  1859-1862. 

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Taking the Napplication rate, method and main varieties applied in paddy field of black soil in Northeast China as the parameters, a micro-plot tracer isotope trial and a normal urea plot trial were conducted for two years to study the fate of fertilizer nitrogen in paddy field. The results showed that 22.2%～46.1% of applied chemical fertilizer nitrogen was absorbed and remained in the paddy plant, and averaged 37.68%. About 12.7% to 25.4 % of applied N during the same year was remained in the soil. The determined nitrogen losses rate through ammonia volatilization in a closed chamber system was 19.0%～44.2%. The use efficiency of chemical fertilizer N was influenced by the application method. Higher use efficiency would be obtained with deeper or mixing application method. The amount of nitrogen remained in soil were related to the application method, and the remained rate was increased with the amount and application depth increasing. The experiment with ¹⁵ showed that no ¹⁵N residue was detected below 80cm in depth, which was because the heavy texture of the black soil. The results of the tracer isotope trial and the plot experiments showed that there was a rough balance between the amount of residual nitrogen in soil and the priming effect from chemical fertilizer nitrogen.

Nitrogen,phosphorus and potassium cycling and balance in farmland ecosystem at the piedmont of Taihang

ZHANG Yuming, HU Chunsheng, MAO Renzhao, DONG Wenxu

2003, (11):  1863-1867. 

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The feature and change trend of N, Pand Kcycling and balance in farmland ecosystem of Luancheng County at the piedmont of Taihang were analyzed.The status of nutrient balance was appraised, and the rational way to apply fertilizer was put forward. The result indicated that N balance went through a process from slight deficit to surplus during 1985～2000, changing from deficit of 1.4% in 1985 to surplus of 48.6% in 2000. Potassium balance changed gradually from serious deficit of 82% to slight surplus of 4.6%, but was still deficit in many fields. Pbudget was surplus ever since 1985. Comparing with the output of nutrients, the inputs of N and P were excessive, but the Kinput was short. Under the current soil fertility and crop planting structure, the countermeasure to control the application amount of Nand Pand to increase the application rate of Kshould be carried out, so that,there would be no significant surplus Nemitting or leaching from soil into environment. The technique to return crop straw into farmland should be extended to increase the nutrient recycling rate.

Effects of soil fertility and nitrogen application rate on nitrogen absorption and translocation, grain yield, and grain protein content of wheat

WANG Yuefu, YU Zhenwen, LI Xiangxia, YU Songlie

2003, (11):  1868-1872. 

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The results of this study showed that nitrogen application improved the nitrogen uptake by wheat, especially during its late growth stage. Although a higher nitrogen application rate could increase the amount of absorbed nitrogen, an excess of nitrogen would remain in vegetative organs at the stage after flowering, owing to the low translocation rate of nitrogen from these organs to the grain, and hence, the nitrogen use efficiency and nitrogen harvest index were decreased. Compared with that on high fertility soil, the ratio of nitrogen absorbed from fertilizer to total absorbed nitrogen was higher when the wheat was grown on low fertility soil. On high fertility soil, wheat plant absorbed more nitrogen from top-dressed fertilizer than from basis fertilizer, and top-dressed fertilizer contributed more nitrogen to the grain. It was reversed on low fertility soil.

Construction of conceptual model of data management for nutrient cycling research

SHI Jianping, SUN Bo, YANG Linzhang

2003, (11):  1873-1878. 

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Alarge amount of data have been accumulated from the agro-ecosystem nutrient cycling research during recent years. It is necessary to develop a data management system for global decision-making and for preserving from loss. This paper outlined a conceptual model design based on Entity-Relation (E-R) model, presented the model constructing process from user query,and demonstrated a database system using a given model. The results showed that the database implemented from the designed model could provide the function of querying in terms of time, location and theme, and management of various types of data, such as field observation, theme map and research report, and fast extracting and analysis data with spatio-temporal characteristic.

Characteristics of nutrient leaching from paddy field in Taihu Lake area

LIAN Gang, WANG Dejian, LIN Jinghui, YAN Dezhi

2003, (11):  1879-1883. 

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In recent years, excessive nutrient loss in subsurface drainage from agricultural land is identified as a major source of non-point source pollution, and has been attended globally. This study was conducted to determine the effect of nutrient leaching from paddy field in rice-planting season under different fertilizer application levels on water quality by using Lysimeter experiment. The results showed that the concentration of NH₄⁺-N in surface water raised quickly after fertilization, reached the highest in 2 or 3 days with the maximum value of 26.2 mg·L^-1,and then,dropped quickly within 7 or 10 days. The concentration of NH₄⁺-N in leachate was very low, only accounted for 0.008%～0.074% of total fertilizer applied. The nitrate content in the solution and lossed from leaching increased gradually with fertilizer application rate, with a range from 0 to 7.14 mg·L^-1. The nitrate concentration in leachate over the soil profile was characterized by a gradual increase from the top to bottom. Nitrogen was leached away mainly in the form of NO₃^--N in rice-planting season, and the net NO₃^--N loss was 3.2～8.3kg·hm^-2,accounted for 1.40%～2.78%.Under the experiment level, nitrogen leaching may lead to a potential pollution of underground water. The concentration of phosphorus in surface water reached the highest in one day after fertilization, after then dropped. The concentration of phosphorus in lower depth was very low, almost not affected by the amount of fertilizer applied. Application of pig manure could increase the transfer of phosphorus.

Ammonia volatilization loss of nitrogen fertilizer from rice field and wet deposition of atmospheric nitrogen in rice growing season

SU Chengguo, YIN Bin, ZHU Zhaoliang, SHEN Qirong

2003, (11):  1884-1888. 

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Plot and field experiments showed that the NH₃ volatilization loss from rice field reached its maximum in1～3 days after N-fertilization, which was affected by the local climate conditions (e.g., sun illumination, temperature, humidity, wind speed, and rainfall), fertilization time, and ammonium concentration in surface water of the rice field. The wet deposition of atmospheric nitrogen was correlated with the application rate of Nfertilizer and the rainfall. The amount of nitrogen brought into soil or surface water by the wet deposition in rice growing season reached 7.5 kg·hm^-2. The percent of NH₄⁺-N in the wet deposition was about 39.8%～73.2%, with an average of 55.5%. There was a significant correlation of total ammonia volatilization loss with the average concentration of NH₄⁺-N in wet deposition and total amount of wet deposition in rice growing season.

Soil fertility evolution, nutrient balance and reasonable fertilization in paddy field in southern area of Jiangsu Province

LI Ronggang, YANG Linzhang, PI Jiahuan

2003, (11):  1889-1892. 

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With the integration of macro-statistical data, micro-survey data and parameters obtained from previous studies, the soil fertility evolution and nutrient balance in paddy fields in southern Jiangsu were analyzed to provide evidence of scientific fertilizer application. It was showed that from 1982 to 1996, the total nitrogen and organic matter contents in Wuxi paddy fields had a rapid increase, phosphorus had a slow increase, and potassium had a general decrease. Soil nutrient balance analysis in Wuxi and Changzhou cities showed that nitrogen was commonly surplus, potassium was generally inadequate, and phosphorus was different from nitrogen and potassium. Phosphorus was surplus in Wuxi city and inadequate in Changzhou city. On the basis of nutrient balance, the reasonable nitrogen, phosphorus and potassium fertilizer application amount was 488.9, 113.1 and 235.1 kg穐m^-2 in Wuxi, and 499.4, 112.5 and 234.2 kg穐m^-2 in Changzhou paddy fields, respectively. Due to the nitrogen accumulation and potassium absence in soil, the nitrogen and potassium application amount should be lower and higher than the above reasonable nitrogen and potassium application amount.

Effects of long-term fertilization on wheat yield on Loess Plateau

HAO Mingde, LAI Lu, WANG Gailing, DANG Tinghui

2003, (11):  1893-1896. 

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The effect of long-term fertilization on the yield of winter wheat was studied on the basis of 18-year located experiment on the Loess Plateau. The results showed that the winter wheat yield increased 418.1 kg穐m^-2 under Nfertilization, and the average increasing rate was different with precipitation. In average and rain rich year, the average increasing rate were 30.3% and 58.9%,respectively,but in drought year, the yield decreased,and its average decreasing rate was 13.9%. The winter wheat yield under Pfertilizer increased in drought year, and decreased in average and rain rich year. The average increasing rate was 6.5% in drought year,and the average decreasing rate was 15.4% and 10.0%,respectively. The average increasing rate in M, NP, PM, NM and NPM was 82.8%, 127.8%, 18.9%, 144.4%, and 169.3%, respectively. In addition, precipitation affected the amount of spike, grains per spike,and weight of thousand-grains.

Articles

Effect of different mulching on spring corn yield and on soil environment in Loess Plateau

FANG Riyao, TONG Yanan, LIANG Dongli, FANG Juan

2003, (11):  1897-1900. 

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Effecm of different mulching nn sgtring corn yield and on soil environment in Loess Plateau, Heyang County were studied. The results showed that different mulching could increase the crorn yield significantly. Soil water rnn-tents were increased remarkably except normal plastic film mulching, and the upper soil Layer kept wet far a long time-Mulching could also reduce temperature difference of day and night, kcett soil surface from direct precipita-Lion lash, and maintain better sail structure. Compared with straw mulching, normal plastic film and no mulching, water osmosis plastic film could increase the yield by 6.4%,23.6% and 29.1%,the water use elliciency 21.5, 20.2,17.4 and 16.7 kg·mm^{·hm-2,respectively.Straw mufrhing could remarkably increase soil organic matter and soil fertility. Water asmvxis plastic film had the same effect of inereasistg temperature as normal plastic film. While air temperatum was more than 35℃,water osmosis pla.Rtir fi3m had the fuactinn of reduring extreme temperawre, but long term mulching would promote exctssine mincralixation of soil organic ni-trogen and leaching of NO₃-N.}

Effect of plastic-film mulch on water and nitrogen use by spring maize and on fate of applied nitrogen in the southern Loess Plateau

DANG Tinghui, HAO Mingde, GUO Shengli, CAI Guixin

2003, (11):  1901-1905. 

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The relationships between nitrogen and yield and between water and yield, and the fate of nitrogen under plastic film mulching for spring maize were studied with field plots and microplots in the southern Loess Plateau. The results showed that plastic-film mulching(N₁₂₀ C) could increase maize yield by 46.7%,comparing with no-mulching(N₁₂₀ UC) in same rate of fertilizer. The maize yield potentiality of mulching might be played fully, comparing with CK (no nitrogen),treatments N₁₂₀ (urea nitrogen 120 kg·hm^-2), N₁₈₀ (urea nitrogen180 kg·hm^-2) and N₁₂₀ M(urea nitrogen120 kg·hm^-2 +organic manure nitrogen60 kg·hm^-2) could raise grain yield by 41.8%, 43.9% and 34.7%,respectively.Mulching planting raised water use efficiency (WUE) by 57.9 %, and raised rainfall use efficiency (RUE) by 54.5%. N₁₂₀, N₁₈₀ and N₁₂₀ Mimproved WUE by 38.4 %, 47.4% and 32.4%, respectively, and improved RUE by 42.3%, 43.9% and 34.7%, respectively. Because the organic manure applied was not fully rotted cattle dung, which supplied available nitrogen slowly than urea, it raised yield and WUEto a low extent. Meanwhile, the experiment showed that 73.0%～83.7% of water used by maize from rainfall, which indicated that the key water to determine maize yield was rainfall in spring maize growth period. Mulching planting for maize had little impact on the fate of nitrogen fertilizer.The total recovery of nitrogen had little difference, NUE decreased 7.3%,and residual Nin soil raised 6.4%,comparing with N₁₂₀ UC. Agreat part of the residual N was in0～20cm of soil,and no risk occurred for nitrogen leaching and accumulation to deeper soil layers in the first growth season.

Effect of soil bulk density on maize growth under different water regimes

LIU Wangou, SHAN Lun

2003, (11):  1906-1910. 

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Split-root experiments were conducted with maize under both low (-0.86 MPa) and high (-0.17 MPa) soil matrix potential conditions, in which, maize roots were divided equally between two compartments in partitioned galvanized steel containers containing Lou soil. Four treatments were installed, i.e., low bulk density (both compartments packed to 1.2 g穋m^-3), medium density (both compartments packed to 1.33 g穋m^-3), high density (both compartments packed to 1.45 g穋m^-3), and mixed density (one compartment packed to 1.2, the other to 1.45 g穋m^-3). The results showed that high soil bulk density and low matrix potential had a significant effect on root and shoot growth, but the effect of low matrix potential was more profound. There was a significant decrease in root dry matter and shoot dry weight, but the shoot growth was reduced more significantly than root growth, when the plants were grown on compacted soils or the soil matrix potential reached -0.86MPa from -0.17MPa. Both leaf expansion rate and plant size reductions occurred under high soil mechanical resistance caused by increased bulk density or lowered soil water content. The smaller size of plants in compacted treatments was due to the reduced leaf expansion rates and the smaller maximum size of individual mature leaf. In contrast, when plants were grown in soil with mixed bulk density, there was an enhanced growth of root in low-density soil to compensate or even overcompensate the reduced growth in high-density soil, and hence, the plant growth was comparable with that in low bulk density soil.

Comparison of roots distribution in different maize plant type cultivars in the Songnen Plain

SONG Ri, WU Chunsheng, MA Liyan, GUO Jixun, XING Fu

2003, (11):  1911-1913. 

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By soil column culture and field experiment, the comparison of roots distribution of spreading-leaf and upright-leaf maize cultivars in the Songnen Plain was studied. The results showed that there were differences in the roots distribution of different maize cultivars. The maximum of root dry weight appeared on the 15th day and 30th day after silking for spreading-leaf and upright-leaf maize cultivar, respectively. Compared to spreading-leaf maize cultivar, the root dry weight of upright-leaf maize cultivar was higher by 12.2%. The vertical distribution of different maize cultivar roots was different. The root dry weight rate below 20 cm depth of spreading-leaf maize cultivar was less than 19%, whereas that of upright-leaf maize cultivar was more than23%. Compared with spreading-leaf maize cultivar, the root dry weight rate at 40～100 cm depth was higher by 43.3%. There were differences between the different maize cultivars in the horizontal roots distribution. The roots of upright-leaf maize cultivar distributed tightly in horizon. The percentage of root dry weight of upright-leaf maize cultivar in a horizontal area 0～10 cm from the plant center was higher than that of spreading-leaf maize cultivar by 9.6%. Upright-leaf maize cultivar had more roots in deeper soil depth and it distributed tightly in horizon. Therefore, it was suitable for compact-planting. It was easier to acquire high yield for upright-leaf maize cultivar because it had good roots distribution characteristics.

Colonization of silicate bacterium strain NBT in wheat roots

Sheng Xiafang

2003, (11):  1914-1916. 

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The strain NBT of silicate bacterium was labelled with streptomycin,and a stable streptomycin resistance strain NBT was obtained.Its colonization dynamics and affecting factors in wheat rhizosphere were studied in agar plates and greenhouse pots were studied by counting the method with selective medium. The results of pot culture experiment showed that strain NBT could successfully colonize in the rhizosphere of wheat.In pot cultures of sterile soil,the highest colonization level (3.4?10⁷cfu穏^-1 root soil) was reached on9th day after seeds sown;at 54th day, the population of strain NBT tended to stable, and decreased to 1.4?10⁴cfu穏^-1 root soil.In pot cultures of unsterile soil, the highest colonization level (3.8?10⁷cfu穏^-1 root soil) was reached at 9th day,and the population of strain NBT tended to a stationary state at 60th day,with the numbers being 1.4?10⁴cfu穏^-1 root soil. Some biological and abiotic factors could greatly influence the colonization of the beneficial microorganism.

Effects of potash fertilizer on nutrient absorption by peanut and its yield and benefit

ZHOU Kejin, MA Chengzhe, XU Chengbao, LI Dingbo

2003, (11):  1917-1920. 

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Studies in Jianghuai hilly region showed that at definite Nand Plevels, applying potash fertilizer could regulate the transportation and distribution of nutrients in peanut plants, accelerate their absorption of N, Pand K, increase the dry matter accumulation in their reproductive organs, and increase their yield, quality, and disease resistance. For each 100 kg pod products, the absorption of N, P and K was 3.08～5.35 kg, 0.6～1.2 kg and 3.45～6.66 kg, respectively. The Kabsorption was the biggest, and it was accumulated mainly in nutritive organs. The absorbed N and P were mainly accumulated in pods and other reproductive organs. The contents of N, P and K in all organs were increased with increasing potassium levels, and the amount of increased Kwas the biggest. The yield and economic benefit were the highest when the amount of applied potassium reached to 150～180 kg·hm^-2 and N:P:K=2:1:2. The highest pod yield was 5425.5 kg·hm^-2, the highest benefit was 13878.7 yuan·hm^-2, and the ratio of output/input reached 6.75:1. The yield and economic benefit of peanut were decreased obviously when the amount of applied potassium was over 225 kg·hm^-2. Thus, the prescription of N 150, P75 and K150 was recommended for the balance fertilization of peanut production in this region.

Effect of low molecular weight organic acids on Pb²⁺ adsorption and desorption by constant charge soil colloids

YANG Yati, WANG Xudong, ZHANG Yiping, QU Aihua

2003, (11):  1921-1924. 

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The isothermal curves of Pb ²⁺ adsorption-desorption by soil colloids followed Freundlich and Langmuir equation. The adsorption constant Ka showed the trend of old manured loessal soil >yellow loessal soil>dark cultivated loessal soil>yellow cinamon soil, which was consistent with surface charge density σ₀, an indicator of the strength of Pb ²⁺ adsorption by each soil colloid. Low molecular- weight organic acids (LMWOAs) made Pb ²⁺ adsorbed amount decreased and adsorption affinity increased, and the effect of citric acid was larger than that of oxalic acid. The constant K_d of residual Pb ²⁺ adsorption after desorption showed the trend of old manured loessal soil > yellow cinamon soil > dark cultivated loessal soil > yellow loessal soil, which reflected the adsorption strength of residual Pb ²⁺ after desorption, and was related to the contents of organic matter and free ferric oxide. The isothermal curves of Pb ²⁺ desorption from soil colloids were obvious higher than those of Pb ²⁺ adsorption. In NaNO₃ and oxalic acid background solution, the isothermal curves of Pb ²⁺ adsorption were far away from those of Pb ²⁺ desorption, showing that the hysteretic degree between adsorption and desorption was very large. The isothermal curves of Pb ²⁺ desorption from soil colloids were closed to those of Pb ²⁺ adsorption in citric acid background solution, which showed that the Pb adsorption and desorption was reversible.

Microbial eco-characteristics of reclaimed mining wasteland in red soil area of Southern ChinaⅠ.Effects on soil microbial activity

LONG Jian, HUANG Changyong, TEN Ying, YAO Huaiying

2003, (11):  1925-1928. 

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Studies on the soil microbes,soil enzyme activity and soil biochemical intensity in copper mining wasteland indicated that the total quantity of major soil microbes declined by 68.43%～80.32%,compared with that of the non-minig soil. The proportion of bacteria and actinomyces decreased, while that of fungi did not changed obviously. The amount of major physiological groups including ammonifiers, nitrogen fixing bacteria, cellulose decomposing bacteria, aerobic nitrogen fixing bacteria and anaerobic nitrogen fixing bacteria all decreased, and soil basic respiration descended, compared with the control. The activity of soil enzymes weakened,which included urease, sucrase, proteinase, acid phosphtase, peroxidase, polyphenol oxidase and dehydrogenase. Soil biochemical intensity including ammonification, nitrification, nitrogen fixation and cellulose decomposition descended, and the circulation of Cand Nin mining soil inhibited. All the results showed that the weakening of microbial activity was one of major characteristics in reclaimed mining soil.

Articles

Biodegradation of herbicide pendimethalin by fungi and its characteristics

LIN Aijun, ZHU Lusheng, WANG Jun, LIU Aiju, SUN Ruilian

2003, (11):  1929-1933. 

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Fungi, which can grow on and degrade pendimethalin,were isolated from activated sludge and soil.The biodegradation characterization in vitro was studied. The results showed that pendimethalin could be degraded by fungi, 16 fungi were isolated by enrichment culture,among which,10 fungi could degrade more than60% pendimethalin in 5 days in culture fluid. According to the physiological resistance and the capacity to degrade pendimethalin,three fungi were considered as efficiently degrading strains identified as Aspergillus terreus, Monilochaetes and Aspergillus furnigatus. The efficiency of degradation was affected by culture conditions such as pH,temperature, and concentration of cane sugar and pendimethanlin. The results showed that when the additional carbon source was 0.5%～1.0%, pH value was 6～8,and cultivated temperature was 20～30℃, the growth amount of fungi and the degradation rate were enhanced. The fungi grew quickly, and the biodegradation rate was high under pendimethalin concentration being 100 mg·L^-1. The removed amount of pendimethalin increased with increasing pendimethalin concentration. The optimal conditions were proposed,which could provide theoretic basis for prevention and control of pesticides pollution.

Evaluation of interactive efficacy of two mycoinsecticides and low application rate imidacloprid in controlling greenhouse whitefly Trialeurodes vaporariorum(Homoptera: Aleyrodidae)

CHEN Bin, FENG Mingguang

2003, (11):  1934-1938. 

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The interactive effects of pure emulsifiable formulations (10¹⁰ conidia? ml^-1) of Beauveria bassiana and Paecilomyces fumosoroseus conidia and 1% and 3% of imidacloprid 10% WPwere tested for controlling greenhouse whitefly,Trialeurodes vaporariorum, on lettuce grown in four polyethylene film-covered greenhouses (5m?100 m) in Kunming, Yunnan. Six fungal treatments, two imidacloprid ones, and one water-spray control were included in the experiment,with each being replicated in three plots (7m?5 m穚lot^-1).For each of the treatments, 1000-fold aqueous dilution (10⁷ conidia穖l^-1) was sprayed twice at a 15-d interval,with the first spray given on day 11 after lettuce transplantation. Counts of live and dead whiteflies from each treatment were made on the initial day, and then, once every five days. During a 30-d period of observation from August 20, the two applications of the fungal formulations alone or those containing low rates of imidacloprid 10% WPeffectively protected the lettuce from damage by T. vaporariorum,and generated relative efficacies.Whitefly density decreased >95%, which was significantly higher than that attributed to the low application rates of imidacloprid 10% WP. Based on the estimations of relative efficacy and percent density decrease,P.fumosoroseus treatments controlled the whiteflies better than B.bassiana ones,and the effects of both fungi on the pest population were apparently enhanced with the quantity of imidacloprid added.The differences among the fungal treatments in the two estimations were larger during the first 10 days,but decreased thereafter,becoming insignificant on day 10 after the second spray. The results indicated that the fungal formulations tested in this study are of great potential for practical use in whitefly control,and their efficacy could be enhanced with low rates of imidacloprid.

Adaptation of Sogatella furcifera to insect-resistant rice variety N₂₂

CHEN Jianming, YU Xiaoping, LU Zhongxian, TAO linyong, ZHENG Xusong, XU Hongxing, CHENG Jia'an

2003, (11):  1939-1942. 

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The adaptation of whitebacked planthopper (WBPH) Sogatella furcifera to insect-resistant rice variety N₂₂ and the variation of its protective enzyme were studied by rearing it successively two generations on N₂₂ and insect-susceptible rice variety TN₁ in laboratory. The results showed that after reared on TN₁ or N₂₂ for one or two generations, its egg period, nymphal duration, and total generation period had no significant difference. The ecological parameters, e.g., nymphal survival rate, body weight, amount of honey dew, egg number, and innate increasing rate of WBPH transferred from TN₁ to N₂₂ and reared for one generation were lower than those of WBPH reared on N₂₂ successively for two generations, and the latter was lower than that reared on TN₁. The activities of superoxide dismutase (SOD) and catalase (CAT) in protective enzyme system of the 2nd generation WBPHon N₂₂ were similar to those of the pest on TN₁, indicating that S. furcifera could adapt to insect-resistant variety N₂₂ after rearing it successively for several generations.

Articles

Suppressive effect of plant secondary substances and ecological measures on Liriomyza sativae population

XIAN Jidong, LIANG Guangwen, ZENG Ling, PANG Xiongfei

2003, (11):  1943-1946. 

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Astate-space population model was used to evaluate the effect of plant secondary substances and ecological measures on the population dynamics of the vegetable leafminer, Liriomyza sativae.In the vegetable field, by spraying alcohol extracts of Lantana camara (1 g?100 ml^-1), or spraying the petroleum spray oil (300?), or releasing the parasitoids, the indices of population control(IIPC) of L.sativae compared with control were 0.136, 0.222 and 0.292,respectively, but the index of population trend of vegetable leafminer in control was as high as 11.15, the population of vegetable leafminer still increased by control each one of the methods. Based on the state space analysis, the controlling effects of the alcohol extracts combining with other methods on vegetable leafminer were stimulated, which showed that the alcohol extracts from Lantana camara (1 g?100 ml^-1) plus horticultural spray oils(300?) used once at the period of adult summit, and the parasitoids released 1000 to 2000 per 100 m² gave the index of population of vegetable leafminer below 1, means that vegetable leafminer would be controlled sustainably.

Establishment and analysis of laboratory population life table of Trichogramma dendrolimi developed on Antherea pernyi eggs

XU Chunting, HUANG Shoushan, LIU Wenhui, HAN Shichou, CHEN Qiaoxian, LI Liying

2003, (11):  1947-1950. 

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The laboratory population life table of Trichogramma dendrolimi Matsumura developed on the eggs of Antherea pernyi was established by calculating the survival rate at immature stage and the adult reproduction.The survival rate of egg, larval and pupa was 1.00,0.9186 and 0.8895, respectively,and the emergence rate of pupa was 0.8668.The total mortality rate at immature stage reached to 30%, which was a great difference from those developed on small host eggs.Each Trichogramma female could lay about 86 eggs on one Antherea pernyi egg.The index of Trichogramma population trend was 54.48.Analysis on the relationships among intrinsic rate of natural increase (r_m), net production rate (R₀) and index of population trend (I) showed that the R₀ and Ihad the same biological meaning, and r_m could be calculated with Ivalue.

Articles

Behavior ecological study on copulation and oviposition of Apis cerana cerana Fab

YU Linsheng, MENG Xiangjin, WU Chengwu

2003, (11):  1951-1954. 

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The behavior ecology of copulation and oviposition of Apis cerana cerana Fab. was studied. The results showed that temperature influence on the cell-covered time of Apis cerana cerana queen and drone induced the remarkable difference in their newborn weight and mature time (P<0.05). Queen and drone fly frequency for discerning cell was 1.23～1.31 and 1.08～1.13,and duration was 0.12～0.13h and 0.16～0.20h. Their copulation fly frequency was 1.10～1.12 and 1.10～1.05,and duration was 0.22～0.23h and 0.18～0.23h. The most suitable temperature for copulation was 20～28℃. The number of semen in side-oviduct of the queen in each copulation fly was 3.37×10⁶～4.15×10⁶,and in natural copulation,semen number in spermathecal sac was 3.55 ×10⁶～3.62×10⁶. There was a direct relationship between queen newborn weight and ovulation number. The annual effect of climate and flower fertility on the queen's ovulation number was obvious.

Analysis on instantaneous spatial pattern of thermal force field in Harbin

ZHU Ning, WANG Cheng, ZHOU Hongze, LI Min

2003, (11):  1955-1958. 

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The spatial pattern of urban thermal force field is not only the dominant content in assessing city ecological environment, but also an important base for city green system planning. The status of spatial pattern of thermal force field in Harbin was analyzed with RSand GIStechniques. Based on the instantaneous radiation temperature of the land surfaces in the city when the TMimage was sensed remotely, all the patches were divided into 3 levels, i.e., low radiation temperature (<10℃), middle radiation temperature (10～22℃), and high radiation temperature of the land surfaces (22～31℃). The patches with high radiation temperature accounted for 61%, those with low radiation temperature accounted for 17%, and those with middle radiation temperature accounted for 22%. 7018 patches (12252 hm² in total) with super-thermal radiation (>28℃) were uneven in their areas. The biggest area in these patches was 1489 hm², and the smallest one was 0.72 hm². The proportion of the patches with an area less than1 hm², between1～5 hm², and more than5 hm² was 95.02%, 3.46%, and 1.58 %, respectively. There were 3 types of spatial patterns of the super-thermal radiation patches, i.e., round form (the average radiation temperature was 30.8℃), ring form (the average radiation temperature was 27℃), and pieces form (the average radiation temperature was 24.7℃). Daowai District and Daoli District were round form, districts along the ring routes of railway in the city were ring form, and Nangang District and Dongli District were pieces form. Some advices to resolve the problem of ‘heat island effect' influenced by the factors including greenland covering rate, greenland area and building dimension were discussed.

Spatial distribution of water quality in Xiangxi River,China

YE Lin, LI Daofeng, TANG Tao, QU Xiaodong, CAI Qinghua

2003, (11):  1959-1962. 

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Cluster analysis and principal component analysis were used to analyze the physical and chemical characteristics of water samples collected from 19 sampling sites along Xiangxi River.The result of cluster analysis showed that Xiangxi River could be divided into three reaches,which belonged to different sub-basins.The principle component analysis on each reach showed that the main information of water quality was different from each other.In the upper reach,the main information of river water quality was hardness and total alkalinity;in the middle reach,the main information was dissolved phosphorus,total phosphorus and Cl^-,in the lower reach,the main information was pH,NO₂^--N,total nitrogen and COD.Furthermore,considering the geographical and environmental backgrounds of the Xiangxi River basin,the reason that caused the different distribution pattern of water quality in Xiangxi River was discussed.Hence,a simple approach to analyze the spatial distribution of water quality was provided.

Articles

Structural characteristics of phytoplankton community during harmful algae bloom in Jiaozhou Bay

LIU Dongyan, SUN Jun, ZHANG Liyong

2003, (11):  1963-1966. 

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Based on two days survey in August,2001 in Jiaozhou Bay,the structural characteristics of phytoplankton community during harmful algae bloom was studied. The results showed that phytoplankton community was composed mainly by the coastal warm species, which were dominated by the diatom including37 species. Only 7 Pyrrorophya and 1 Chlorophyta species were identified. The highest value of species number appeared in the central of Jiaozhou Bay, which included 37 species, but the lowest value in the edge of Jiaozhou Bay was only 10 species. The highest value of cell abundance appeared in the eastern waters of Jiaozhou Bay, being 6.96?10⁸cell穖^-3,and the lowest value appeared in the mouth of Jiaozhou Bay,being 3.18?10⁶ cell穖^-3.The diversity and eveness of phytoplankton was the lowest in the eastern waters of Jiaozhou bay, but was higher in the mouth and the central of Jiaozhou Bay. Water mass movement and eutrophication were the main factors affecting the distribution of phytoplankton community in Jiaozhou Bay.

Effect of temperature on the translocation of exogenous ³²P in water column, Microcystis aeruginosa and sediments

SHI Xiaoli, WANG Fengping, JIANG Lijuan, ZHOU Zhi, YANG Liuyan, KONG Zhiming, GAO Guang, QIN Boqiang

2003, (11):  1967-1970. 

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Effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water,Microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. Exogenous ³²P was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of different temperature. Then, the translocation of ³²P was significantly affected by the growth of M.aeruginosa in the ecosystem. Relatively high temperature was favorable to the growth of M.aeruginosa and accelerated the adsorption of exogenous phosphorus. The maximum concentration of exogenous endocellular phosphorus in M.aeruginosa was only related with the initial phosphorus concentration of water environment. The growth curve of M.aeruginosa contained short lag phase, 7-day log phase and decline phase but no obvious stationary phase at 25℃. After certain amounts of exogenous phosphorus were accumulated in M.aeruginosa,its growth was independent of the amounts of endocellular phosphorus at 25℃. The exogenous ³²P moved from water and M.aeruginosa to sediment continuously and almost all of them transferred into sediment through the sedimentation of M.aeruginosa at the end of the experiment. The concentration of dissoluble exogenous ³²P declined rapidly when water temperature was high and was less than 0.00716 mg·L^-1 after 7 days.

Articles

Spatial heterogeneity of pelagic fishery resources in the East China Sea

SU Fenzhen, ZHOU Chenghu, ZHANG Tianyu, DU Yunyan, YAO Changqin

2003, (11):  1971-1975. 

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Quantitative description of spatial heterogeneity can help the understanding of the distribution of fishery resources and its relationship with the environment from ecological view. Based on geographic information system, the Geary index for the density distribution of pelagic fish was calculated, and the semivariograms were drawn. The Geary value c was 0.25 and Co/ (Co+C) was 19.1%, indicating that the distribution of the pelagic fish had a high spatial autocorrelation with anisotropy. The sharp slope of semivariogram in the directions of 45? and 135? meant that there existed important dynamic environmental processes in the two directions. The annual fluctuation of fishery resource density was caused by the spatial autocorrelation, because the density had a significantly positive correlation with value C, but no correlation with C0. The fractal dimension Dwas negatively correlated with the density, meaning that the density increase was resulted from the increase of spatial fish centralizing.

Enzyme activities in soils contaminated by abandoned copper tailings

TENG Ying, HUANG Changyong, LONG Jian, YAO Huaiying, LIU Fang

2003, (11):  1976-1980. 

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Studies on the enzyme activities and heavy metal contents in soils polluted by abandoned copper tailings showed that the contents of heavy metals in contaminated soils were higher than those in no-polluted soils, and the enzyme activities, especially dehydrogenase and urease activities were decreased significantly with increasing contamination. Multivariate regression analysis indicated that soil dehydrogenase activity was very significantly correlated with the combined effect of several heavy metals, and urease, protease or acid phosphatase activity was significantly related to the combined effect of them. The total enzyme activity of soil might be a useful index in management of these highly contaminated soils, and hence, it is feasible to use this index as a primary biochemical parameter to evaluate heavy metals compound pollution.

Investigation on the vegetation of copper tailing wasteland in Shizishan,Tongling, Anhui Province

LI Ying, WANG Youbao, LIU Dengyi

2003, (11):  1981-1984. 

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Investigation on the vegetations of the copper tailing wasteland was conducted in Shizishan, Tongling, Anhui Province. Total 49 species of natural colonized plant, belonging to 15 families and 38 genera, were found, among which, 26 species were annual plant, and 20 species perennial. Most of species were belonging to Compositae (12 species), Gramineae (11 species), and Leguminesae (8 species). 5 relatively stable communities were found. The main limiting factors of vegetation distribution were extreme infertility of the wasteland, high concentration of heavy metals (especially, the concentration of Cu and Cd in the wasteland were 30 times as those in the normal soil), and degree of natural recolonization.

Articles

Effect of zinc fertilization on cadmium uptake and accumulation in two barley (Hordeum vulgare) cultivars

Zhu Yongguan

2003, (11):  1985-1988. 

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Apot experiment was carried out in a greenhouse to investigate the interactive effects of Zn-Cd on the growth and the uptake of Cd and Zn by two barley genotypes (Sahara and Clipper).The results showed that under the conditions of this experiment,adding Cd and Zn had no significant effect on the shoot biomass of either cultivars, but applying Zn tended to reduce the root biomass of both cultivars. With the amount of less than20 mg穔g^-1, Zn addition did not affect Cd concentration in plant tissues; while at 40 mg穔g^-1,it decreased Cd concentrations significantly in plant tissues of both cultivars. Total Cd uptake by both cultivars decreased with increasing in Zn application, mainly due to the decrease in root biomass. The two genotypes were significantly different in Zn uptake, but this difference did not affect Cd uptake. Cd concentration in roots of Zn-efficient cultivar Sahara was lower than that of Zn-inefficient cultivar Clipper.

Effect of phosphorus on arsenic adorption by three different soils

LEI Mei, CHEN Tongbin, FAN Zhilian, MO Liangyu, HUANG Zechun

2003, (11):  1989-1992. 

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The effect of phosphorus on arsenic adsorption by yellow soil, red soil and brown soil was studied using batch experiment. The results indicated that the arsenic without Pamendment adsorption capacity of three tested soils was yellow soil>red soil>brown soil.The maximal adsorption capacity of yellow soil and red soil was decreased with 60 mg穔g^-1 phosphorus added,and that of brown soil was increased with 20 mg穔g^-1 phosphorus added.The arsenic adsorption capacity of three soils was greater when P:As=1:2 than that when P:As=1:1 and P:As=2:1, and the differences between P:As=1:1 and P:As=2:1 treatments were not significant. Observations could be better fitted by Langmuir equations.

PAEs in composts of municipal sludge and rice straw

CAI Quanying, MO Cehui, ZHU Xizhen, WU Qitang, WANG Boguang, LI Guirong

2003, (11):  1993-1996. 

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Four composting treatments for municipal sludge and rice straw were carried out, which included turning composting, inoculation-turning composting, continuous aeration, and intermittent aeration. GC/MS determination of phthalic acid esters (PAEs) in different composted composts showed that the total contents of six PAEcompounds (∑PAEs) ranged from 0.980～17.832 mg·kg^-1, decreasing in the order of turning composting (17.832 mg·kg^-1) >inoculation-turning composting (13.927 mg·kg^-1) >intermittent aeration (10.765 mg·kg^-1) > continuous aeration (9.815 mg·kg^-1). DnOP was dominated in the composts. The degradation rate of ∑PAEs after composting was 1.37～45.71% (mean27.63%), and that of diethyl phthalate (DEP), di-n-butyl phthalate (DnBP) and butylbenzyl phthalate (BBP) was 95.76～98.68%, 79.56～99.46% and 87.42～98.42%, respectively. The concentration of di-n-octyl phthalate (DnOP) was increased in the composts. Aeration-composting, and continuous aeration composting in particular, was more efficient than other treatments to degrade PAEs in municipal sludge.

Effect of pig manure and rice straw on biological activity of Cd-contaminated soil

ZHANG Yali, SHEN Qirong, XIE Xuejian, SUN Zhaohai

2003, (11):  1997-2000. 

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Studies on the effects of pig manure and rice straw on the biological activity of Cd-contaminated permeable paddy soil showed that Cd-contaminated soil had a declined biological activity. After applying organic manure, the content of soil available Cd decreased significantly, being about 40%, and soil microbial C, Nand Pand soil dehydrogenase and catalase activities increased 30%～100%. There existed a negative correlation between soil available Cd and soil microbial Cand N, indicating that microbial Cand Ncould be used as an index of Cd-contaminated soil.

Effect of municipal sludge and chemical fertilizers on phthalic acid esters (PAEs) contents in Ipomoea aquatica grown on paddy soils

CAI Quanying, MO Cehui, ZHU Xizhen, WU Qitang, WANG Boguang, JIANG Chengai, LI Haiqin

2003, (11):  2001-2005. 

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GC/MSdeterminations on six phthalic acid esters (PAEs) in Ipomoea aquatic grown on potted paddy soil fertilized with municipal sludge and chemical fertilizers showed that the total contents of PAEs (∑PAEs) in Ipomoea aquatic aboveground parts ranged from².129mg·kg^-1 to 7.111 mg·kg^-1,decreasing in order of Guangzhou sludge + fertilizers (7.111 mg·kg^-1)>Guangzhou sludge (4.767 mg·kg^-1)>Foshan sludge (3.569 mg·kg^-1)>Foshan sludge + fertilizers (3.305 mg·kg^-1)>fertilizers (2.638 mg·kg^-1)>control (2.129 mg·kg^-1),indicating that compared with control,fertilization increased ∑PAEs in Ipomoea aquatica to a different extent. Only certain compounds of PAEs in different treatments of Ipomoea aquatica were dominant,e.g.,butylbenzyl phthalate(BBP) in control,chemical fertilizers,Foshan sludge,and Guangzhou sludge accounted for 40 % to 80% of ∑PAEs,di-n-butyl phthalate(DnBP) in Foshan sludge + chemical fertilizers accounted for 56%,while di-n-octyl phthalate(DnOP),di(2-ethylhexyl)phthalate(DEHP) and BBPin Guangzhou sludge + chemical fertilizers accounted for approximately 30%. ∑PAEs and the contents of its most compounds were higher in the plants of Ipomoea aquatica than in its roots to a different extent.

Succession of Larix olgensis and Betula platyphlla-marsh ecotone communities in Changbai Mountain

MU Changcheng

2003, (11):  1813-1819. 

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The succession of communities within the ecotone between forest and marsh in Changbai Mountain was studied to identify the interrelation between the succession of ecotone communities and the mesophytization of the ecotone. The succession regime of the ecotone communities was studies by patch size (the volume of each mound) and age class of different tree species, water transmission from soil to atmosphere through the transpiration of different tree species, and regional climate warming and community succession. The results demonstrated that both patch size and water loss through transpiration were increased with age class. The increased volume of mounds and water loss through transpiration of trees were converted to the raised ground surface level and the lowered ground surface water level. Within60 years, the ground surface level would be raised by 0.405～0.590 m, depending on the distance to the marsh, and the aboveground water level would be lowered by 1.050～1.442 m. Climate had a great effect on the community dynamics. Community succession and regional climate warming intensified the mesophytization process of forest marsh ecotone, and the ecotone communities would eventually change into forest communities within a relatively short period.

Nutrient characteristics in leaves of broadleaved seedlings in south China

XUE Li, WEI Ruping, TAN Tianyong, KUANG Ligang, WEI Meiman

2003, (11):  1820-1824. 

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Nutrient concentrations and contents in leaves of broadleaved Elaeocarpus sylvestris,Castanopsis hystrix,Ormosia pinnata,Michelia macclurei,Camellia semiserata,Liquidambar formosana,Castanopsis fissa,Mytilaria laosensis and Cinnamomum camphora seedlings were studied. Leaf N,Pand Kconcentrations in Ormosia pinnata,Castanopsis fissa and Cinnamomum camphora were higher than those of other tree species,and leaf N,Pand Kcontents in Camellia semiserata,Castanopsis fissa and Cinnamomum camphora were higher than those of other tree species. Mean leaf nutrient concentration in upper crown and lower crown of 9 tree species was N 16.67 and 17.09 g穔g^-1,P1.29 and 0.84 g穔g^-1,K11.77 and 6.65 g穔g^-1,respectively. Mean leaf nutrient content in upper crown and lower crown of 9 tree species was N 0.871 and 1.069 g穖^-2,P0.065 and 0.052 g穖^-2,K0.608 and 0.426 g穖^-2,respectively. Leaf Pand Kconcentrations and contents in the upper crown were generally higher than those of the lower crown. From the view of nutrient contents,mixing Camellia semiserata with other tree species,mixing Castanopsis hystrix or Mytilaria laosensis with Elaeocarpus sylvestris,Liquidambar formosana,Ormosia pinnata,Castanopsis fissa,and Cinnamomum camphora,and mixing Michelia macclurei with Castanopsis fissa and Cinnamomum camphora were suitable.

Water storage characteristics of ground covers under three forests in Three Gorges Area

CHENG Jinhua, ZHANG Hongjiang, SHI Yuhu, CHENG Yun, QI Shenglin, HE Fan, PAN Lei

2003, (11):  1825-1828. 

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Through water holding experiments and the survey of ground covers under three forests (mixed forest of Quercus variabilis and Pinus massoniana, pure Quercus variabilis forest and pure Pinus massoniana forest) in Three Gorges Area, the hydrological characteristic parameters,e.g.,maximum water holding capacity and water absorption speed, were measured.The results showed that the maximum water holding capacity of moss under pure Quercus variabilis forest is the highest (303.1 % of its dry weight), that under mixed forest of Quercus variabilis and Pinus massoniana was 283.8 %,and that under pure Pinus massoniana forest was 242.3 %.The maximum water holding capacity of litter under mixed forest stand of Quercus variabils and Pinus massoniana was 282.2 % of its dry weight, that under pure Quercus variabilis forest is 262.5 %, that under pure Pinus massoniana forest was 239.3 %.The equation between water absorption speed of ground cover and its immersed period could be S=kt n.The results also showed that when the forests were all in mid-age, the water holding ability of the mosses was higher than that of the litters under the same forest.The ground cover's variation with its immersed period had no relation to forest types.

Ecological effects of bagging on actinidia fruits

CHEN Zhijie, ZHANG Shulian, ZNANG Feng, SHI Yongqiang

2003, (11):  1829-1832. 

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Studies on the ecological effects of bagging on actinidia fruits showed that under different types of bagging,the ecological effects on actinidia fruits were different.Bagging with membrane changed the conditions of temperature and humidity.The inside temperature raised by 0.7～0.9 ℃,humidity increased by 10.8%～11.8%,single fruit weight increased by 25.7%～37.7%,commercial fruit rate raised by 20.4%～30.1%,percentage of diseases and pests decreased by 85.7%～90.2%,and storage property was good.Additionally,the application rate of chemical pesticide was reduce by 72.2%,and the concentration of remnant pesticide inside fruits was only 0.31% mg·kg^-1,which was decreased by 90.0%.The chemical pesticide pollution in ecological circumstance and actinidia fruits both reduced.It would be a new way for the rgeen fruits production in the future.Bagging with paper has obvious negative effects.

Articles

Effects of light on carotenoid biosynthesis and color formation of citrus fruit peel

TAO Jun, ZHANG Shanglong, AN Xinmin, ZHAO Zhizhong

2003, (11):  1833-1836. 

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The effects of shading fruit with opaque paper bag at the late stage of fruit enlargement on the contents of chlorophyll, carotenoid and in “Hongshigan” citrus (C.reticulata × C.sinensis) fruit peel and its color were examined. The results showed that after shading,the chlorophyll content in peel decreased quickly, which resulted in its earlier color shifting. In contrast, the contents of total carotenoids and each carotenoid component did not increase,but decreased significantly. At the stage of fruit riping, both chlorophyll in shaded and unshaded fruit disappeared,and the shaded fruit,owing to its lower level of carotenoids, had a lighter color than the unshaded fruit. The sugar content in peel of shaded fruit did not differ obviously from that of unshaded fruit at the earlier stage, but dropped markedly at the late stage of shading. Removing the enclosing paper bag from shaded fruit at the late stage of shading resulted in the increase of sugar, and correspondingly in the increase of carotenoid, especially of β-cryptoxanthin accumulation with consequent darkening of fruit color.These results stressed the effect of light on stimulating carotenoid synthesis,especially the accumulation of β-cryptoxanthin in citrus fruit peel. The light is the enviromental signal essential for carotenoid synthesis in citrus fruit peel during certain stage of fruit development.

Semi-nested LP-PCR-SSCP identification of arbuscular endomycorrhizal fungi diversity of Alnus at Changbai Mountain

LI Yiye, HE Xingyuan, ZHANG Zhongze, ZHANG Chenggang

2003, (11):  1837-1841. 

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The diversity of arbuscular endomycorrhizal fungi colonized on three species of Alnus at Changbai Mountain was identified based on coupling the sensitivity of semi-nested LP-PCR and the specificity afforded by Single Strand Conformation Polymorphism analysis. It is suggested that altitudes and species of Alnus were not the important factors deciding the distribution of AMF in the grade of family, and there was at least one species of Glomaceae, Glomus intraradix, dominated in Alnus at Changbai Mountain.

Physiological response to salt-alkali stress in experimental populations in two ecotypes of Leymus chinensis in the Songnen Plains of China

ZHOU Chan, YANG Yunfei

2003, (11):  1842-1846. 

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The comparative study of physiological reaction to salt, alkali and mixed salt stresses in two ecotypes of grey-green and yellow-green of Leymus chinensis were made. At the stage of seedling, the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers were determined in planting containers with sands in two ecotypes by stress of salt, alkali and mixed salt of different concentrations. The results of quantitative analysis showed that the relationships between the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers and concentration of salt, alkali and mixed salt could expressed as linear equation, which were significant or obviously significant. There were capabilities of salt-alkali resistance in the physiological characteristics of two populations, but the capabilities of salt-alkali resistance were stronger in grey-green ecotype than in yellow-green ecotype. The differentiation of the content of chlorophyll, the leakage rate of electrolyte of leaves, free proline and Na/K of tillers were significant or obviously significant in two ecotypes under three kinds of salt stress. Physiological characteristics of salt-alkali resistance were significantly different in two ecotypes. The study provided physiological evidence for making sure that the main ecological factor was salt-alkali. It resulted in adaptive differentiation in Leymus chinensis ecotypes.

Module structure of Leymus chinensis clones under cultivated condition in Songnen Plains of China

YANG Yunfei, ZHANG Baotian, LI Jiandong

2003, (11):  1847-1850. 

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Leymus chinensis is a perennial rhizome grass, a species of typical clonal plant. In the Songnen Plains of China, the ramets of the clone consist of tillers and seedlings under cultivated condition during the last stage of growing season. The tillering nodes of the ramets could propagate four generations, with enough growing space and no interspecies competition in the sandy soil habitats during a growing season. According to the vegetative reproductive generations of tillering nodes, the age spectrum was the largest on the modules of the first age classes for present or potential clones, which reduced obviously with increasing age classes, and they were all expanding type on the age structure. The productivity of every ramet module correlated largely with the time length for growing and the formation of the ramets. The earlier formation time and the longer growing time, the greater the tillers contributed to material production and vegetative reproduction of the clone. There was a certain capability of adjustment for the spatial expansion and the material storage of the test clones.

Seed germination characteristics and regeneration mechanism of Stellera chamaejasme population

XING Fu, GUO Jixun, WANG Yanhong

2003, (11):  1851-1854. 

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Stellera chamaejasme is a perennial herbaceous plant of Thymelaceae, as one of major poisonous plant species to animal, distributing in Northeast, Northwest, and Southeast of China. In some area on the degraded steppes, the plant grew with abnormal abundance and badly endangered the health of animals. The germination capacity of Stellera chamaejasme seed that collected from soil seed bank and immediately gathered from the plant was studied under different temperature, light condition and five pretreatments (rupture seed pericarp, remove seed pericarp, soaked in 98% H₂SO₄ for 5 min, soaked in0.2 % KNO₃ for 24 h, and kept at 10℃ for a week). The seed germination percentage (GP) of the plant was lower in the mass and it was 13% under constant temperature 25℃ with dark condition. The suitable temperatures for germination of the seeds were constant 30℃ or alternative 10～30℃. To rupture or to remove seed pericarp could significantly increase GPand it was 49% and 47%, respectively. GPunder pretreatment of seed soaked in 98% H₂SO₄ for 5 min was 32%. The pretreatments of seed soaked in0.2 % KNO₃ for 24 h and seed kept at 10℃ for a week had no significantly effects on increasing GP. The seed germination was not sensitive to light condition. The hardness of the seeds was mainly responsible for the seed dormancy and low germination rate. The GP of S. chamaejasme seeds in the soil seed bank was higher than that gathered in the immediate year. Based on the comprehensive analysis with the lower GP and the results of field observation, it was concluded that S. chamaejasme seeds did not germinate every year in nature, and chance of population regeneration was random or periodic.

Contribution of fertilization development to yield production and its geographic differentiation

YU Wantai, ZHANG Lu, MA Qiang, YIN Xiuyan, SHEN Shanmin

2003, (11):  1855-1858. 

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The results of long-term field experiments at three stations in different areas of China indicated that the contribution of fertilization to crop yield was significantly affected by the thermal condition of climate and the fertilization system. In the case of optimum fertilization, the largest contribution rate was 0.31 (average of fourteen years) at Hailun Station (in temperate zone), 0.39 (average of twelve years) at Shenyang Station (in warmer-temperate zone), and 0.42 (average of eleven years) at Taoyuan Station (in subtropical zone), which showed that the existence of geographic differentiation was caused by the thermal condition of local climate. Therefore, keeping the optimum fertilization systems, the largest contribution rate to crop yield could be estimated from 30% to 50%, depending on the local climate condition. The interaction of fertilization and thermal factor between Shenyang and Taoyuan was much bigger than that between Shenyang and Hailun. The interaction between organic manure and thermal condition of local climate was bigger than that between chemical fertilizer and thermal condition of local climate.

Fate of fertilizer nitrogen in paddy field of black soil region

HAN Xiaozeng, WANG Shouyu, SONG Chunyu, QIAO Yunfa

2003, (11):  1859-1862. 

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Taking the Napplication rate, method and main varieties applied in paddy field of black soil in Northeast China as the parameters, a micro-plot tracer isotope trial and a normal urea plot trial were conducted for two years to study the fate of fertilizer nitrogen in paddy field. The results showed that 22.2%～46.1% of applied chemical fertilizer nitrogen was absorbed and remained in the paddy plant, and averaged 37.68%. About 12.7% to 25.4 % of applied N during the same year was remained in the soil. The determined nitrogen losses rate through ammonia volatilization in a closed chamber system was 19.0%～44.2%. The use efficiency of chemical fertilizer N was influenced by the application method. Higher use efficiency would be obtained with deeper or mixing application method. The amount of nitrogen remained in soil were related to the application method, and the remained rate was increased with the amount and application depth increasing. The experiment with ¹⁵ showed that no ¹⁵N residue was detected below 80cm in depth, which was because the heavy texture of the black soil. The results of the tracer isotope trial and the plot experiments showed that there was a rough balance between the amount of residual nitrogen in soil and the priming effect from chemical fertilizer nitrogen.

Nitrogen,phosphorus and potassium cycling and balance in farmland ecosystem at the piedmont of Taihang

ZHANG Yuming, HU Chunsheng, MAO Renzhao, DONG Wenxu

2003, (11):  1863-1867. 

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The feature and change trend of N, Pand Kcycling and balance in farmland ecosystem of Luancheng County at the piedmont of Taihang were analyzed.The status of nutrient balance was appraised, and the rational way to apply fertilizer was put forward. The result indicated that N balance went through a process from slight deficit to surplus during 1985～2000, changing from deficit of 1.4% in 1985 to surplus of 48.6% in 2000. Potassium balance changed gradually from serious deficit of 82% to slight surplus of 4.6%, but was still deficit in many fields. Pbudget was surplus ever since 1985. Comparing with the output of nutrients, the inputs of N and P were excessive, but the Kinput was short. Under the current soil fertility and crop planting structure, the countermeasure to control the application amount of Nand Pand to increase the application rate of Kshould be carried out, so that,there would be no significant surplus Nemitting or leaching from soil into environment. The technique to return crop straw into farmland should be extended to increase the nutrient recycling rate.

Effects of soil fertility and nitrogen application rate on nitrogen absorption and translocation, grain yield, and grain protein content of wheat

WANG Yuefu, YU Zhenwen, LI Xiangxia, YU Songlie

2003, (11):  1868-1872. 

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The results of this study showed that nitrogen application improved the nitrogen uptake by wheat, especially during its late growth stage. Although a higher nitrogen application rate could increase the amount of absorbed nitrogen, an excess of nitrogen would remain in vegetative organs at the stage after flowering, owing to the low translocation rate of nitrogen from these organs to the grain, and hence, the nitrogen use efficiency and nitrogen harvest index were decreased. Compared with that on high fertility soil, the ratio of nitrogen absorbed from fertilizer to total absorbed nitrogen was higher when the wheat was grown on low fertility soil. On high fertility soil, wheat plant absorbed more nitrogen from top-dressed fertilizer than from basis fertilizer, and top-dressed fertilizer contributed more nitrogen to the grain. It was reversed on low fertility soil.

Construction of conceptual model of data management for nutrient cycling research

SHI Jianping, SUN Bo, YANG Linzhang

2003, (11):  1873-1878. 

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Alarge amount of data have been accumulated from the agro-ecosystem nutrient cycling research during recent years. It is necessary to develop a data management system for global decision-making and for preserving from loss. This paper outlined a conceptual model design based on Entity-Relation (E-R) model, presented the model constructing process from user query,and demonstrated a database system using a given model. The results showed that the database implemented from the designed model could provide the function of querying in terms of time, location and theme, and management of various types of data, such as field observation, theme map and research report, and fast extracting and analysis data with spatio-temporal characteristic.

Characteristics of nutrient leaching from paddy field in Taihu Lake area

LIAN Gang, WANG Dejian, LIN Jinghui, YAN Dezhi

2003, (11):  1879-1883. 

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In recent years, excessive nutrient loss in subsurface drainage from agricultural land is identified as a major source of non-point source pollution, and has been attended globally. This study was conducted to determine the effect of nutrient leaching from paddy field in rice-planting season under different fertilizer application levels on water quality by using Lysimeter experiment. The results showed that the concentration of NH₄⁺-N in surface water raised quickly after fertilization, reached the highest in 2 or 3 days with the maximum value of 26.2 mg·L^-1,and then,dropped quickly within 7 or 10 days. The concentration of NH₄⁺-N in leachate was very low, only accounted for 0.008%～0.074% of total fertilizer applied. The nitrate content in the solution and lossed from leaching increased gradually with fertilizer application rate, with a range from 0 to 7.14 mg·L^-1. The nitrate concentration in leachate over the soil profile was characterized by a gradual increase from the top to bottom. Nitrogen was leached away mainly in the form of NO₃^--N in rice-planting season, and the net NO₃^--N loss was 3.2～8.3kg·hm^-2,accounted for 1.40%～2.78%.Under the experiment level, nitrogen leaching may lead to a potential pollution of underground water. The concentration of phosphorus in surface water reached the highest in one day after fertilization, after then dropped. The concentration of phosphorus in lower depth was very low, almost not affected by the amount of fertilizer applied. Application of pig manure could increase the transfer of phosphorus.

Ammonia volatilization loss of nitrogen fertilizer from rice field and wet deposition of atmospheric nitrogen in rice growing season

SU Chengguo, YIN Bin, ZHU Zhaoliang, SHEN Qirong

2003, (11):  1884-1888. 

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Plot and field experiments showed that the NH₃ volatilization loss from rice field reached its maximum in1～3 days after N-fertilization, which was affected by the local climate conditions (e.g., sun illumination, temperature, humidity, wind speed, and rainfall), fertilization time, and ammonium concentration in surface water of the rice field. The wet deposition of atmospheric nitrogen was correlated with the application rate of Nfertilizer and the rainfall. The amount of nitrogen brought into soil or surface water by the wet deposition in rice growing season reached 7.5 kg·hm^-2. The percent of NH₄⁺-N in the wet deposition was about 39.8%～73.2%, with an average of 55.5%. There was a significant correlation of total ammonia volatilization loss with the average concentration of NH₄⁺-N in wet deposition and total amount of wet deposition in rice growing season.

Soil fertility evolution, nutrient balance and reasonable fertilization in paddy field in southern area of Jiangsu Province

LI Ronggang, YANG Linzhang, PI Jiahuan

2003, (11):  1889-1892. 

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With the integration of macro-statistical data, micro-survey data and parameters obtained from previous studies, the soil fertility evolution and nutrient balance in paddy fields in southern Jiangsu were analyzed to provide evidence of scientific fertilizer application. It was showed that from 1982 to 1996, the total nitrogen and organic matter contents in Wuxi paddy fields had a rapid increase, phosphorus had a slow increase, and potassium had a general decrease. Soil nutrient balance analysis in Wuxi and Changzhou cities showed that nitrogen was commonly surplus, potassium was generally inadequate, and phosphorus was different from nitrogen and potassium. Phosphorus was surplus in Wuxi city and inadequate in Changzhou city. On the basis of nutrient balance, the reasonable nitrogen, phosphorus and potassium fertilizer application amount was 488.9, 113.1 and 235.1 kg穐m^-2 in Wuxi, and 499.4, 112.5 and 234.2 kg穐m^-2 in Changzhou paddy fields, respectively. Due to the nitrogen accumulation and potassium absence in soil, the nitrogen and potassium application amount should be lower and higher than the above reasonable nitrogen and potassium application amount.

Effects of long-term fertilization on wheat yield on Loess Plateau

HAO Mingde, LAI Lu, WANG Gailing, DANG Tinghui

2003, (11):  1893-1896. 

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The effect of long-term fertilization on the yield of winter wheat was studied on the basis of 18-year located experiment on the Loess Plateau. The results showed that the winter wheat yield increased 418.1 kg穐m^-2 under Nfertilization, and the average increasing rate was different with precipitation. In average and rain rich year, the average increasing rate were 30.3% and 58.9%,respectively,but in drought year, the yield decreased,and its average decreasing rate was 13.9%. The winter wheat yield under Pfertilizer increased in drought year, and decreased in average and rain rich year. The average increasing rate was 6.5% in drought year,and the average decreasing rate was 15.4% and 10.0%,respectively. The average increasing rate in M, NP, PM, NM and NPM was 82.8%, 127.8%, 18.9%, 144.4%, and 169.3%, respectively. In addition, precipitation affected the amount of spike, grains per spike,and weight of thousand-grains.

Articles

Effect of different mulching on spring corn yield and on soil environment in Loess Plateau

FANG Riyao, TONG Yanan, LIANG Dongli, FANG Juan

2003, (11):  1897-1900. 

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Effecm of different mulching nn sgtring corn yield and on soil environment in Loess Plateau, Heyang County were studied. The results showed that different mulching could increase the crorn yield significantly. Soil water rnn-tents were increased remarkably except normal plastic film mulching, and the upper soil Layer kept wet far a long time-Mulching could also reduce temperature difference of day and night, kcett soil surface from direct precipita-Lion lash, and maintain better sail structure. Compared with straw mulching, normal plastic film and no mulching, water osmosis plastic film could increase the yield by 6.4%,23.6% and 29.1%,the water use elliciency 21.5, 20.2,17.4 and 16.7 kg·mm^{·hm-2,respectively.Straw mufrhing could remarkably increase soil organic matter and soil fertility. Water asmvxis plastic film had the same effect of inereasistg temperature as normal plastic film. While air temperatum was more than 35℃,water osmosis pla.Rtir fi3m had the fuactinn of reduring extreme temperawre, but long term mulching would promote exctssine mincralixation of soil organic ni-trogen and leaching of NO₃-N.}

Effect of plastic-film mulch on water and nitrogen use by spring maize and on fate of applied nitrogen in the southern Loess Plateau

DANG Tinghui, HAO Mingde, GUO Shengli, CAI Guixin

2003, (11):  1901-1905. 

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The relationships between nitrogen and yield and between water and yield, and the fate of nitrogen under plastic film mulching for spring maize were studied with field plots and microplots in the southern Loess Plateau. The results showed that plastic-film mulching(N₁₂₀ C) could increase maize yield by 46.7%,comparing with no-mulching(N₁₂₀ UC) in same rate of fertilizer. The maize yield potentiality of mulching might be played fully, comparing with CK (no nitrogen),treatments N₁₂₀ (urea nitrogen 120 kg·hm^-2), N₁₈₀ (urea nitrogen180 kg·hm^-2) and N₁₂₀ M(urea nitrogen120 kg·hm^-2 +organic manure nitrogen60 kg·hm^-2) could raise grain yield by 41.8%, 43.9% and 34.7%,respectively.Mulching planting raised water use efficiency (WUE) by 57.9 %, and raised rainfall use efficiency (RUE) by 54.5%. N₁₂₀, N₁₈₀ and N₁₂₀ Mimproved WUE by 38.4 %, 47.4% and 32.4%, respectively, and improved RUE by 42.3%, 43.9% and 34.7%, respectively. Because the organic manure applied was not fully rotted cattle dung, which supplied available nitrogen slowly than urea, it raised yield and WUEto a low extent. Meanwhile, the experiment showed that 73.0%～83.7% of water used by maize from rainfall, which indicated that the key water to determine maize yield was rainfall in spring maize growth period. Mulching planting for maize had little impact on the fate of nitrogen fertilizer.The total recovery of nitrogen had little difference, NUE decreased 7.3%,and residual Nin soil raised 6.4%,comparing with N₁₂₀ UC. Agreat part of the residual N was in0～20cm of soil,and no risk occurred for nitrogen leaching and accumulation to deeper soil layers in the first growth season.

Effect of soil bulk density on maize growth under different water regimes

LIU Wangou, SHAN Lun

2003, (11):  1906-1910. 

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Split-root experiments were conducted with maize under both low (-0.86 MPa) and high (-0.17 MPa) soil matrix potential conditions, in which, maize roots were divided equally between two compartments in partitioned galvanized steel containers containing Lou soil. Four treatments were installed, i.e., low bulk density (both compartments packed to 1.2 g穋m^-3), medium density (both compartments packed to 1.33 g穋m^-3), high density (both compartments packed to 1.45 g穋m^-3), and mixed density (one compartment packed to 1.2, the other to 1.45 g穋m^-3). The results showed that high soil bulk density and low matrix potential had a significant effect on root and shoot growth, but the effect of low matrix potential was more profound. There was a significant decrease in root dry matter and shoot dry weight, but the shoot growth was reduced more significantly than root growth, when the plants were grown on compacted soils or the soil matrix potential reached -0.86MPa from -0.17MPa. Both leaf expansion rate and plant size reductions occurred under high soil mechanical resistance caused by increased bulk density or lowered soil water content. The smaller size of plants in compacted treatments was due to the reduced leaf expansion rates and the smaller maximum size of individual mature leaf. In contrast, when plants were grown in soil with mixed bulk density, there was an enhanced growth of root in low-density soil to compensate or even overcompensate the reduced growth in high-density soil, and hence, the plant growth was comparable with that in low bulk density soil.

Comparison of roots distribution in different maize plant type cultivars in the Songnen Plain

SONG Ri, WU Chunsheng, MA Liyan, GUO Jixun, XING Fu

2003, (11):  1911-1913. 

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By soil column culture and field experiment, the comparison of roots distribution of spreading-leaf and upright-leaf maize cultivars in the Songnen Plain was studied. The results showed that there were differences in the roots distribution of different maize cultivars. The maximum of root dry weight appeared on the 15th day and 30th day after silking for spreading-leaf and upright-leaf maize cultivar, respectively. Compared to spreading-leaf maize cultivar, the root dry weight of upright-leaf maize cultivar was higher by 12.2%. The vertical distribution of different maize cultivar roots was different. The root dry weight rate below 20 cm depth of spreading-leaf maize cultivar was less than 19%, whereas that of upright-leaf maize cultivar was more than23%. Compared with spreading-leaf maize cultivar, the root dry weight rate at 40～100 cm depth was higher by 43.3%. There were differences between the different maize cultivars in the horizontal roots distribution. The roots of upright-leaf maize cultivar distributed tightly in horizon. The percentage of root dry weight of upright-leaf maize cultivar in a horizontal area 0～10 cm from the plant center was higher than that of spreading-leaf maize cultivar by 9.6%. Upright-leaf maize cultivar had more roots in deeper soil depth and it distributed tightly in horizon. Therefore, it was suitable for compact-planting. It was easier to acquire high yield for upright-leaf maize cultivar because it had good roots distribution characteristics.

Colonization of silicate bacterium strain NBT in wheat roots

Sheng Xiafang

2003, (11):  1914-1916. 

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The strain NBT of silicate bacterium was labelled with streptomycin,and a stable streptomycin resistance strain NBT was obtained.Its colonization dynamics and affecting factors in wheat rhizosphere were studied in agar plates and greenhouse pots were studied by counting the method with selective medium. The results of pot culture experiment showed that strain NBT could successfully colonize in the rhizosphere of wheat.In pot cultures of sterile soil,the highest colonization level (3.4?10⁷cfu穏^-1 root soil) was reached on9th day after seeds sown;at 54th day, the population of strain NBT tended to stable, and decreased to 1.4?10⁴cfu穏^-1 root soil.In pot cultures of unsterile soil, the highest colonization level (3.8?10⁷cfu穏^-1 root soil) was reached at 9th day,and the population of strain NBT tended to a stationary state at 60th day,with the numbers being 1.4?10⁴cfu穏^-1 root soil. Some biological and abiotic factors could greatly influence the colonization of the beneficial microorganism.

Effects of potash fertilizer on nutrient absorption by peanut and its yield and benefit

ZHOU Kejin, MA Chengzhe, XU Chengbao, LI Dingbo

2003, (11):  1917-1920. 

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Studies in Jianghuai hilly region showed that at definite Nand Plevels, applying potash fertilizer could regulate the transportation and distribution of nutrients in peanut plants, accelerate their absorption of N, Pand K, increase the dry matter accumulation in their reproductive organs, and increase their yield, quality, and disease resistance. For each 100 kg pod products, the absorption of N, P and K was 3.08～5.35 kg, 0.6～1.2 kg and 3.45～6.66 kg, respectively. The Kabsorption was the biggest, and it was accumulated mainly in nutritive organs. The absorbed N and P were mainly accumulated in pods and other reproductive organs. The contents of N, P and K in all organs were increased with increasing potassium levels, and the amount of increased Kwas the biggest. The yield and economic benefit were the highest when the amount of applied potassium reached to 150～180 kg·hm^-2 and N:P:K=2:1:2. The highest pod yield was 5425.5 kg·hm^-2, the highest benefit was 13878.7 yuan·hm^-2, and the ratio of output/input reached 6.75:1. The yield and economic benefit of peanut were decreased obviously when the amount of applied potassium was over 225 kg·hm^-2. Thus, the prescription of N 150, P75 and K150 was recommended for the balance fertilization of peanut production in this region.

Effect of low molecular weight organic acids on Pb²⁺ adsorption and desorption by constant charge soil colloids

YANG Yati, WANG Xudong, ZHANG Yiping, QU Aihua

2003, (11):  1921-1924. 

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The isothermal curves of Pb ²⁺ adsorption-desorption by soil colloids followed Freundlich and Langmuir equation. The adsorption constant Ka showed the trend of old manured loessal soil >yellow loessal soil>dark cultivated loessal soil>yellow cinamon soil, which was consistent with surface charge density σ₀, an indicator of the strength of Pb ²⁺ adsorption by each soil colloid. Low molecular- weight organic acids (LMWOAs) made Pb ²⁺ adsorbed amount decreased and adsorption affinity increased, and the effect of citric acid was larger than that of oxalic acid. The constant K_d of residual Pb ²⁺ adsorption after desorption showed the trend of old manured loessal soil > yellow cinamon soil > dark cultivated loessal soil > yellow loessal soil, which reflected the adsorption strength of residual Pb ²⁺ after desorption, and was related to the contents of organic matter and free ferric oxide. The isothermal curves of Pb ²⁺ desorption from soil colloids were obvious higher than those of Pb ²⁺ adsorption. In NaNO₃ and oxalic acid background solution, the isothermal curves of Pb ²⁺ adsorption were far away from those of Pb ²⁺ desorption, showing that the hysteretic degree between adsorption and desorption was very large. The isothermal curves of Pb ²⁺ desorption from soil colloids were closed to those of Pb ²⁺ adsorption in citric acid background solution, which showed that the Pb adsorption and desorption was reversible.

Microbial eco-characteristics of reclaimed mining wasteland in red soil area of Southern ChinaⅠ.Effects on soil microbial activity

LONG Jian, HUANG Changyong, TEN Ying, YAO Huaiying

2003, (11):  1925-1928. 

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Studies on the soil microbes,soil enzyme activity and soil biochemical intensity in copper mining wasteland indicated that the total quantity of major soil microbes declined by 68.43%～80.32%,compared with that of the non-minig soil. The proportion of bacteria and actinomyces decreased, while that of fungi did not changed obviously. The amount of major physiological groups including ammonifiers, nitrogen fixing bacteria, cellulose decomposing bacteria, aerobic nitrogen fixing bacteria and anaerobic nitrogen fixing bacteria all decreased, and soil basic respiration descended, compared with the control. The activity of soil enzymes weakened,which included urease, sucrase, proteinase, acid phosphtase, peroxidase, polyphenol oxidase and dehydrogenase. Soil biochemical intensity including ammonification, nitrification, nitrogen fixation and cellulose decomposition descended, and the circulation of Cand Nin mining soil inhibited. All the results showed that the weakening of microbial activity was one of major characteristics in reclaimed mining soil.

Articles

Biodegradation of herbicide pendimethalin by fungi and its characteristics

LIN Aijun, ZHU Lusheng, WANG Jun, LIU Aiju, SUN Ruilian

2003, (11):  1929-1933. 

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Fungi, which can grow on and degrade pendimethalin,were isolated from activated sludge and soil.The biodegradation characterization in vitro was studied. The results showed that pendimethalin could be degraded by fungi, 16 fungi were isolated by enrichment culture,among which,10 fungi could degrade more than60% pendimethalin in 5 days in culture fluid. According to the physiological resistance and the capacity to degrade pendimethalin,three fungi were considered as efficiently degrading strains identified as Aspergillus terreus, Monilochaetes and Aspergillus furnigatus. The efficiency of degradation was affected by culture conditions such as pH,temperature, and concentration of cane sugar and pendimethanlin. The results showed that when the additional carbon source was 0.5%～1.0%, pH value was 6～8,and cultivated temperature was 20～30℃, the growth amount of fungi and the degradation rate were enhanced. The fungi grew quickly, and the biodegradation rate was high under pendimethalin concentration being 100 mg·L^-1. The removed amount of pendimethalin increased with increasing pendimethalin concentration. The optimal conditions were proposed,which could provide theoretic basis for prevention and control of pesticides pollution.

Evaluation of interactive efficacy of two mycoinsecticides and low application rate imidacloprid in controlling greenhouse whitefly Trialeurodes vaporariorum(Homoptera: Aleyrodidae)

CHEN Bin, FENG Mingguang

2003, (11):  1934-1938. 

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The interactive effects of pure emulsifiable formulations (10¹⁰ conidia? ml^-1) of Beauveria bassiana and Paecilomyces fumosoroseus conidia and 1% and 3% of imidacloprid 10% WPwere tested for controlling greenhouse whitefly,Trialeurodes vaporariorum, on lettuce grown in four polyethylene film-covered greenhouses (5m?100 m) in Kunming, Yunnan. Six fungal treatments, two imidacloprid ones, and one water-spray control were included in the experiment,with each being replicated in three plots (7m?5 m穚lot^-1).For each of the treatments, 1000-fold aqueous dilution (10⁷ conidia穖l^-1) was sprayed twice at a 15-d interval,with the first spray given on day 11 after lettuce transplantation. Counts of live and dead whiteflies from each treatment were made on the initial day, and then, once every five days. During a 30-d period of observation from August 20, the two applications of the fungal formulations alone or those containing low rates of imidacloprid 10% WPeffectively protected the lettuce from damage by T. vaporariorum,and generated relative efficacies.Whitefly density decreased >95%, which was significantly higher than that attributed to the low application rates of imidacloprid 10% WP. Based on the estimations of relative efficacy and percent density decrease,P.fumosoroseus treatments controlled the whiteflies better than B.bassiana ones,and the effects of both fungi on the pest population were apparently enhanced with the quantity of imidacloprid added.The differences among the fungal treatments in the two estimations were larger during the first 10 days,but decreased thereafter,becoming insignificant on day 10 after the second spray. The results indicated that the fungal formulations tested in this study are of great potential for practical use in whitefly control,and their efficacy could be enhanced with low rates of imidacloprid.

Adaptation of Sogatella furcifera to insect-resistant rice variety N₂₂

CHEN Jianming, YU Xiaoping, LU Zhongxian, TAO linyong, ZHENG Xusong, XU Hongxing, CHENG Jia'an

2003, (11):  1939-1942. 

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The adaptation of whitebacked planthopper (WBPH) Sogatella furcifera to insect-resistant rice variety N₂₂ and the variation of its protective enzyme were studied by rearing it successively two generations on N₂₂ and insect-susceptible rice variety TN₁ in laboratory. The results showed that after reared on TN₁ or N₂₂ for one or two generations, its egg period, nymphal duration, and total generation period had no significant difference. The ecological parameters, e.g., nymphal survival rate, body weight, amount of honey dew, egg number, and innate increasing rate of WBPH transferred from TN₁ to N₂₂ and reared for one generation were lower than those of WBPH reared on N₂₂ successively for two generations, and the latter was lower than that reared on TN₁. The activities of superoxide dismutase (SOD) and catalase (CAT) in protective enzyme system of the 2nd generation WBPHon N₂₂ were similar to those of the pest on TN₁, indicating that S. furcifera could adapt to insect-resistant variety N₂₂ after rearing it successively for several generations.

Articles

Suppressive effect of plant secondary substances and ecological measures on Liriomyza sativae population

XIAN Jidong, LIANG Guangwen, ZENG Ling, PANG Xiongfei

2003, (11):  1943-1946. 

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Astate-space population model was used to evaluate the effect of plant secondary substances and ecological measures on the population dynamics of the vegetable leafminer, Liriomyza sativae.In the vegetable field, by spraying alcohol extracts of Lantana camara (1 g?100 ml^-1), or spraying the petroleum spray oil (300?), or releasing the parasitoids, the indices of population control(IIPC) of L.sativae compared with control were 0.136, 0.222 and 0.292,respectively, but the index of population trend of vegetable leafminer in control was as high as 11.15, the population of vegetable leafminer still increased by control each one of the methods. Based on the state space analysis, the controlling effects of the alcohol extracts combining with other methods on vegetable leafminer were stimulated, which showed that the alcohol extracts from Lantana camara (1 g?100 ml^-1) plus horticultural spray oils(300?) used once at the period of adult summit, and the parasitoids released 1000 to 2000 per 100 m² gave the index of population of vegetable leafminer below 1, means that vegetable leafminer would be controlled sustainably.

Establishment and analysis of laboratory population life table of Trichogramma dendrolimi developed on Antherea pernyi eggs

XU Chunting, HUANG Shoushan, LIU Wenhui, HAN Shichou, CHEN Qiaoxian, LI Liying

2003, (11):  1947-1950. 

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The laboratory population life table of Trichogramma dendrolimi Matsumura developed on the eggs of Antherea pernyi was established by calculating the survival rate at immature stage and the adult reproduction.The survival rate of egg, larval and pupa was 1.00,0.9186 and 0.8895, respectively,and the emergence rate of pupa was 0.8668.The total mortality rate at immature stage reached to 30%, which was a great difference from those developed on small host eggs.Each Trichogramma female could lay about 86 eggs on one Antherea pernyi egg.The index of Trichogramma population trend was 54.48.Analysis on the relationships among intrinsic rate of natural increase (r_m), net production rate (R₀) and index of population trend (I) showed that the R₀ and Ihad the same biological meaning, and r_m could be calculated with Ivalue.

Articles

Behavior ecological study on copulation and oviposition of Apis cerana cerana Fab

YU Linsheng, MENG Xiangjin, WU Chengwu

2003, (11):  1951-1954. 

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The behavior ecology of copulation and oviposition of Apis cerana cerana Fab. was studied. The results showed that temperature influence on the cell-covered time of Apis cerana cerana queen and drone induced the remarkable difference in their newborn weight and mature time (P<0.05). Queen and drone fly frequency for discerning cell was 1.23～1.31 and 1.08～1.13,and duration was 0.12～0.13h and 0.16～0.20h. Their copulation fly frequency was 1.10～1.12 and 1.10～1.05,and duration was 0.22～0.23h and 0.18～0.23h. The most suitable temperature for copulation was 20～28℃. The number of semen in side-oviduct of the queen in each copulation fly was 3.37×10⁶～4.15×10⁶,and in natural copulation,semen number in spermathecal sac was 3.55 ×10⁶～3.62×10⁶. There was a direct relationship between queen newborn weight and ovulation number. The annual effect of climate and flower fertility on the queen's ovulation number was obvious.

Analysis on instantaneous spatial pattern of thermal force field in Harbin

ZHU Ning, WANG Cheng, ZHOU Hongze, LI Min

2003, (11):  1955-1958. 

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The spatial pattern of urban thermal force field is not only the dominant content in assessing city ecological environment, but also an important base for city green system planning. The status of spatial pattern of thermal force field in Harbin was analyzed with RSand GIStechniques. Based on the instantaneous radiation temperature of the land surfaces in the city when the TMimage was sensed remotely, all the patches were divided into 3 levels, i.e., low radiation temperature (<10℃), middle radiation temperature (10～22℃), and high radiation temperature of the land surfaces (22～31℃). The patches with high radiation temperature accounted for 61%, those with low radiation temperature accounted for 17%, and those with middle radiation temperature accounted for 22%. 7018 patches (12252 hm² in total) with super-thermal radiation (>28℃) were uneven in their areas. The biggest area in these patches was 1489 hm², and the smallest one was 0.72 hm². The proportion of the patches with an area less than1 hm², between1～5 hm², and more than5 hm² was 95.02%, 3.46%, and 1.58 %, respectively. There were 3 types of spatial patterns of the super-thermal radiation patches, i.e., round form (the average radiation temperature was 30.8℃), ring form (the average radiation temperature was 27℃), and pieces form (the average radiation temperature was 24.7℃). Daowai District and Daoli District were round form, districts along the ring routes of railway in the city were ring form, and Nangang District and Dongli District were pieces form. Some advices to resolve the problem of ‘heat island effect' influenced by the factors including greenland covering rate, greenland area and building dimension were discussed.

Spatial distribution of water quality in Xiangxi River,China

YE Lin, LI Daofeng, TANG Tao, QU Xiaodong, CAI Qinghua

2003, (11):  1959-1962. 

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Cluster analysis and principal component analysis were used to analyze the physical and chemical characteristics of water samples collected from 19 sampling sites along Xiangxi River.The result of cluster analysis showed that Xiangxi River could be divided into three reaches,which belonged to different sub-basins.The principle component analysis on each reach showed that the main information of water quality was different from each other.In the upper reach,the main information of river water quality was hardness and total alkalinity;in the middle reach,the main information was dissolved phosphorus,total phosphorus and Cl^-,in the lower reach,the main information was pH,NO₂^--N,total nitrogen and COD.Furthermore,considering the geographical and environmental backgrounds of the Xiangxi River basin,the reason that caused the different distribution pattern of water quality in Xiangxi River was discussed.Hence,a simple approach to analyze the spatial distribution of water quality was provided.

Articles

Structural characteristics of phytoplankton community during harmful algae bloom in Jiaozhou Bay

LIU Dongyan, SUN Jun, ZHANG Liyong

2003, (11):  1963-1966. 

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Based on two days survey in August,2001 in Jiaozhou Bay,the structural characteristics of phytoplankton community during harmful algae bloom was studied. The results showed that phytoplankton community was composed mainly by the coastal warm species, which were dominated by the diatom including37 species. Only 7 Pyrrorophya and 1 Chlorophyta species were identified. The highest value of species number appeared in the central of Jiaozhou Bay, which included 37 species, but the lowest value in the edge of Jiaozhou Bay was only 10 species. The highest value of cell abundance appeared in the eastern waters of Jiaozhou Bay, being 6.96?10⁸cell穖^-3,and the lowest value appeared in the mouth of Jiaozhou Bay,being 3.18?10⁶ cell穖^-3.The diversity and eveness of phytoplankton was the lowest in the eastern waters of Jiaozhou bay, but was higher in the mouth and the central of Jiaozhou Bay. Water mass movement and eutrophication were the main factors affecting the distribution of phytoplankton community in Jiaozhou Bay.

Effect of temperature on the translocation of exogenous ³²P in water column, Microcystis aeruginosa and sediments

SHI Xiaoli, WANG Fengping, JIANG Lijuan, ZHOU Zhi, YANG Liuyan, KONG Zhiming, GAO Guang, QIN Boqiang

2003, (11):  1967-1970. 

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Effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water,Microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. Exogenous ³²P was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of different temperature. Then, the translocation of ³²P was significantly affected by the growth of M.aeruginosa in the ecosystem. Relatively high temperature was favorable to the growth of M.aeruginosa and accelerated the adsorption of exogenous phosphorus. The maximum concentration of exogenous endocellular phosphorus in M.aeruginosa was only related with the initial phosphorus concentration of water environment. The growth curve of M.aeruginosa contained short lag phase, 7-day log phase and decline phase but no obvious stationary phase at 25℃. After certain amounts of exogenous phosphorus were accumulated in M.aeruginosa,its growth was independent of the amounts of endocellular phosphorus at 25℃. The exogenous ³²P moved from water and M.aeruginosa to sediment continuously and almost all of them transferred into sediment through the sedimentation of M.aeruginosa at the end of the experiment. The concentration of dissoluble exogenous ³²P declined rapidly when water temperature was high and was less than 0.00716 mg·L^-1 after 7 days.

Articles

Spatial heterogeneity of pelagic fishery resources in the East China Sea

SU Fenzhen, ZHOU Chenghu, ZHANG Tianyu, DU Yunyan, YAO Changqin

2003, (11):  1971-1975. 

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Quantitative description of spatial heterogeneity can help the understanding of the distribution of fishery resources and its relationship with the environment from ecological view. Based on geographic information system, the Geary index for the density distribution of pelagic fish was calculated, and the semivariograms were drawn. The Geary value c was 0.25 and Co/ (Co+C) was 19.1%, indicating that the distribution of the pelagic fish had a high spatial autocorrelation with anisotropy. The sharp slope of semivariogram in the directions of 45? and 135? meant that there existed important dynamic environmental processes in the two directions. The annual fluctuation of fishery resource density was caused by the spatial autocorrelation, because the density had a significantly positive correlation with value C, but no correlation with C0. The fractal dimension Dwas negatively correlated with the density, meaning that the density increase was resulted from the increase of spatial fish centralizing.

Enzyme activities in soils contaminated by abandoned copper tailings

TENG Ying, HUANG Changyong, LONG Jian, YAO Huaiying, LIU Fang

2003, (11):  1976-1980. 

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Studies on the enzyme activities and heavy metal contents in soils polluted by abandoned copper tailings showed that the contents of heavy metals in contaminated soils were higher than those in no-polluted soils, and the enzyme activities, especially dehydrogenase and urease activities were decreased significantly with increasing contamination. Multivariate regression analysis indicated that soil dehydrogenase activity was very significantly correlated with the combined effect of several heavy metals, and urease, protease or acid phosphatase activity was significantly related to the combined effect of them. The total enzyme activity of soil might be a useful index in management of these highly contaminated soils, and hence, it is feasible to use this index as a primary biochemical parameter to evaluate heavy metals compound pollution.

Investigation on the vegetation of copper tailing wasteland in Shizishan,Tongling, Anhui Province

LI Ying, WANG Youbao, LIU Dengyi

2003, (11):  1981-1984. 

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Investigation on the vegetations of the copper tailing wasteland was conducted in Shizishan, Tongling, Anhui Province. Total 49 species of natural colonized plant, belonging to 15 families and 38 genera, were found, among which, 26 species were annual plant, and 20 species perennial. Most of species were belonging to Compositae (12 species), Gramineae (11 species), and Leguminesae (8 species). 5 relatively stable communities were found. The main limiting factors of vegetation distribution were extreme infertility of the wasteland, high concentration of heavy metals (especially, the concentration of Cu and Cd in the wasteland were 30 times as those in the normal soil), and degree of natural recolonization.

Articles

Effect of zinc fertilization on cadmium uptake and accumulation in two barley (Hordeum vulgare) cultivars

Zhu Yongguan

2003, (11):  1985-1988. 

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Apot experiment was carried out in a greenhouse to investigate the interactive effects of Zn-Cd on the growth and the uptake of Cd and Zn by two barley genotypes (Sahara and Clipper).The results showed that under the conditions of this experiment,adding Cd and Zn had no significant effect on the shoot biomass of either cultivars, but applying Zn tended to reduce the root biomass of both cultivars. With the amount of less than20 mg穔g^-1, Zn addition did not affect Cd concentration in plant tissues; while at 40 mg穔g^-1,it decreased Cd concentrations significantly in plant tissues of both cultivars. Total Cd uptake by both cultivars decreased with increasing in Zn application, mainly due to the decrease in root biomass. The two genotypes were significantly different in Zn uptake, but this difference did not affect Cd uptake. Cd concentration in roots of Zn-efficient cultivar Sahara was lower than that of Zn-inefficient cultivar Clipper.

Effect of phosphorus on arsenic adorption by three different soils

LEI Mei, CHEN Tongbin, FAN Zhilian, MO Liangyu, HUANG Zechun

2003, (11):  1989-1992. 

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The effect of phosphorus on arsenic adsorption by yellow soil, red soil and brown soil was studied using batch experiment. The results indicated that the arsenic without Pamendment adsorption capacity of three tested soils was yellow soil>red soil>brown soil.The maximal adsorption capacity of yellow soil and red soil was decreased with 60 mg穔g^-1 phosphorus added,and that of brown soil was increased with 20 mg穔g^-1 phosphorus added.The arsenic adsorption capacity of three soils was greater when P:As=1:2 than that when P:As=1:1 and P:As=2:1, and the differences between P:As=1:1 and P:As=2:1 treatments were not significant. Observations could be better fitted by Langmuir equations.

PAEs in composts of municipal sludge and rice straw

CAI Quanying, MO Cehui, ZHU Xizhen, WU Qitang, WANG Boguang, LI Guirong

2003, (11):  1993-1996. 

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Four composting treatments for municipal sludge and rice straw were carried out, which included turning composting, inoculation-turning composting, continuous aeration, and intermittent aeration. GC/MS determination of phthalic acid esters (PAEs) in different composted composts showed that the total contents of six PAEcompounds (∑PAEs) ranged from 0.980～17.832 mg·kg^-1, decreasing in the order of turning composting (17.832 mg·kg^-1) >inoculation-turning composting (13.927 mg·kg^-1) >intermittent aeration (10.765 mg·kg^-1) > continuous aeration (9.815 mg·kg^-1). DnOP was dominated in the composts. The degradation rate of ∑PAEs after composting was 1.37～45.71% (mean27.63%), and that of diethyl phthalate (DEP), di-n-butyl phthalate (DnBP) and butylbenzyl phthalate (BBP) was 95.76～98.68%, 79.56～99.46% and 87.42～98.42%, respectively. The concentration of di-n-octyl phthalate (DnOP) was increased in the composts. Aeration-composting, and continuous aeration composting in particular, was more efficient than other treatments to degrade PAEs in municipal sludge.

Effect of pig manure and rice straw on biological activity of Cd-contaminated soil

ZHANG Yali, SHEN Qirong, XIE Xuejian, SUN Zhaohai

2003, (11):  1997-2000. 

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Studies on the effects of pig manure and rice straw on the biological activity of Cd-contaminated permeable paddy soil showed that Cd-contaminated soil had a declined biological activity. After applying organic manure, the content of soil available Cd decreased significantly, being about 40%, and soil microbial C, Nand Pand soil dehydrogenase and catalase activities increased 30%～100%. There existed a negative correlation between soil available Cd and soil microbial Cand N, indicating that microbial Cand Ncould be used as an index of Cd-contaminated soil.

Effect of municipal sludge and chemical fertilizers on phthalic acid esters (PAEs) contents in Ipomoea aquatica grown on paddy soils

CAI Quanying, MO Cehui, ZHU Xizhen, WU Qitang, WANG Boguang, JIANG Chengai, LI Haiqin

2003, (11):  2001-2005. 

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GC/MSdeterminations on six phthalic acid esters (PAEs) in Ipomoea aquatic grown on potted paddy soil fertilized with municipal sludge and chemical fertilizers showed that the total contents of PAEs (∑PAEs) in Ipomoea aquatic aboveground parts ranged from².129mg·kg^-1 to 7.111 mg·kg^-1,decreasing in order of Guangzhou sludge + fertilizers (7.111 mg·kg^-1)>Guangzhou sludge (4.767 mg·kg^-1)>Foshan sludge (3.569 mg·kg^-1)>Foshan sludge + fertilizers (3.305 mg·kg^-1)>fertilizers (2.638 mg·kg^-1)>control (2.129 mg·kg^-1),indicating that compared with control,fertilization increased ∑PAEs in Ipomoea aquatica to a different extent. Only certain compounds of PAEs in different treatments of Ipomoea aquatica were dominant,e.g.,butylbenzyl phthalate(BBP) in control,chemical fertilizers,Foshan sludge,and Guangzhou sludge accounted for 40 % to 80% of ∑PAEs,di-n-butyl phthalate(DnBP) in Foshan sludge + chemical fertilizers accounted for 56%,while di-n-octyl phthalate(DnOP),di(2-ethylhexyl)phthalate(DEHP) and BBPin Guangzhou sludge + chemical fertilizers accounted for approximately 30%. ∑PAEs and the contents of its most compounds were higher in the plants of Ipomoea aquatica than in its roots to a different extent.

Factor optimization for municipal domestic wastes treatment by earthworms and its concentration of heavy metals

CHEN Yucheng, PI Guangjie, HUANG Lunxian, DING Derong, YANG Yong

2003, (11):  2006-2010. 

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Simulated experiments,plot tests and applied stuties were conducted to determine the effects of the composition of municipal domestic wastes,their softening and culturing methods,and circumstance temperature on the treatment of municipal domestic wastes (MDW) by earthworms. The results showed that the decomposition rate of MDWand the multiplication rate of earthworms could be elevated by enhancing the C/Nratio of MDW,softening it with earthworms excrements,and culturing with indoor layer at 20℃. Meanwhile,the treatment of MDW was also improved by the hybridization of tamed Chongqing Aisenia foetida and Caliginsoa. The concentration coefficient of heavy metals had no correlation with intenerating method,but were depended upon the types of heavy metals and the culturing method. Arsenic and cadmium were the most easily concentrated,while mercury oppositely. The concentration element in ridge culture was more easily than that in layer culture,and the concentration element in outdoors culture was more easily than that in indoors culturing.

Effects of surfactants on degradation of phenanthrene by Mycobacterium ssp

JIANG Xia, OU Ziqing, YING Peifeng, Ayfer Yediler, Antonious Ketrrup

2003, (11):  2011-2014. 

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With isotopic techniques, the effects of the concentration,ionic type,and straight chain length of surfactants on the degradation of phenanthrene by Mycobacterium ssp.KR2 were studied. The results showed that in the presence of surfactants, the degradation of phenanthrene was not increased. It was delayed in high concentrations of surfactants (≥20 mg·L^-1). Tween80 in its low concentration(≤10 mg·L^-1) was used as a preferential substrate utilized by Mycobacterium ssp.KR2. The degradation was affected by the ionic types of surfactants, and the inhibition to the phenanthrene degradation was cationic surfactant TDTMA>anionic surfactant LAS>nonionic surfactant Tween80. Different lengths of surfactant straight chains had different influence on the degradation of phenanthrene.

CH₄ and N₂O emissions from phaeozem rice field and their mitigative measures

YUE Jin, LIANG Wei, WU Jie, SHI Yi, HUANG Guohong

2003, (11):  2015-2018. 

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Determinations on the CH₄ and N₂O emissions from phaeozem rice field showed that their emission amount in rice growing season was much lower than any other regions in China.There was trade-off relationship between CH₄ and N₂O emissions(r=-0.513,P<0.05). Under the same fertilization,compared with continual irrigation, intermittent irrigation could reduce significantly CH₄ emission and increase N₂O emission,but the overall warming potential of greenhouse effect was reduced greatly,while rice yield was not affected.Therefore,intermittent irrigation was an effective irrigation measures to reduce greenhouse gas emissions from rice field. In addition,investigations on CH₄ and N₂Oemissions and their related microbial process showed a positive relation between methanogens number and CH₄ emission(R²=0.82,P<0.05),and the important relationship between the numbers of nitrifiers and denitrifiers and N₂O emissions.

Articles

Dynamics of dissolved organic matter in terrestrial ecosystem and its environmental impact

WANG Genmei, ZHOU Lixiang

2003, (11):  2019-2025. 

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Dissolved organic matter (DOM), the most active organic carbon pool in terrestrial ecosystem, has a greater effect on the mobilization, translocation, and ecological toxicity of many inorganic and organic pollutants in environment. The DOM concentration in farmlands varies from 10 to 80 mgC·L^-1, while most of wetlands contain25～50 mgC·L^-1 of DOM, which is similar to the leachate from forest soils. However, soil DOM can be increased to above 200～1000 mgC·L^-1 in the rhizosphere or in the plots amended with organic manures. Generally, soil DOM containing a great deal of lower molecular weight fractions or hydrophilic fractions is more mobile and readily biodegradable, compared to the DOM with larger molecular weight or hydrophobic fractions. However, soils with lower pHand higher amount of oxides can adsorb DOM more strongly, and as a result, the mobile DOM in the soils will be reduced. Liming, water-logging, dry-wet recycling and higher temperature can increase the concentration of soil DOM. Furthermore, DOM can enhance the dissolution and translocation of inorganic and organic pollutants, due to the formation of DOM-pollutant complex, resulting in environmental risks. It was suggested that the dynamics of DOM in terrestrial ecosystem and the transportation flux and model of DOM or its associated pollutants from terrestrial to aquatic ecosystem should be considered in future research.

Theories and techniques of degraded wetland ecosystem restoration

PENG Shaolin, REN Hai, ZHANG Qianmei

2003, (11):  2026-2030. 

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Wetlands are the lands transitional between terrestrial and aquatic ecosystems. They provide humanity many services and commodities,are the habitats of wildlife, can control the water cycling and the biogeochemical cycling of nitrogen and carbon,and can filter and decompose the pollutants. The wetlands suffer loss and degradation because of reclamatio and human disturbance. Some theories, such as self-design versus design theory, succession theory, invasion theory, flood pulsing theory, edge effect theory, and intermediate disturbance hypothesis, can be used to direct the restoration of wetlands. Techniques of wetland restoration include to restore the natural hydrologic conditions, to rehabilitate suitable vegetation types, to control human disturbance, to meliorate the soil or landscape, to construct the buffer region,and so on.

Advances in plant ecophysiological studies on re-vegetation of degraded ecosystems

ZHAO Ping

2003, (11):  2031-2036. 

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Natural force and human intervention lead to many local, regional, and sometimes global changes in plant community patterns. Regardless of the cause and intensity of these changes, ecosystem can recover most of their attributes through natural succession, or can be repaired by human assistance. The essentiality of restoration of degraded ecosystem is community succession, a process during which an ecosystem evolves from primary stage to advanced stage,and its structure and function change from simple to complex plant. Ecophysiological study could explain some macroscopical phenomena of the ecology of re-vegetation of degraded ecosystem, and provide a scientific base for assembling pioneering plant community. The advances in plant ecophysiological study on re-vegetation of degraded ecosystems were reviewed in this paper.

Advances in studies on the structure of farmland shelterbelt ecosystem

LI Chunping, GUAN Wenbin, FAN Zhiping, SU Fanxin, WANG Xilin

2003, (11):  2037-2043. 

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The ecological function of farmland shelterbelt system is determined by its structure. The spatio-temporal structure is a key aspect in related researches, which is very necessary to study the integrity, stability and durability of shelterbelt modules. In this article, the researches on the structure of farmland shelterbelt ecosystem were reviewed from the four scales of tree structure, shelterbelt structure, shelterbelts network and landscape structure. The principles, methods and productions of each scale were summarized, and the prospects were also discussed. Dynamic simulation of tree growth process in shelterbelts could be conducted by the theory of form and quality structure of tree and by fractal graphics, which were helpful to study the mechanism of individual trees and belts based on photosynthetic and transpiration mechanism of individual trees.The mechanism model of shelterbelt porosity should be conducted,so that,the sustainable yield model of shelterbelt management could be established, and the optimized model of shelterbelt networks with multi-special and multi-hierarchical structure could also be formed. Evaluating the reasonability, stability and durability of shelterbelt landscape based on the theories and methods of landscape ecology was an important task in the future studies.

Effects of nitrogen forms on nutrient uptake and growth of trees

ZHANG Yandong, BAI Shangbin

2003, (11):  2044-2048. 

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Forest tree species take up both NH₄⁺-N and NO₃^--N forms of nitrogen (N) during their growth. However, the effects of Nform on nutrition uptake and tree growth are different due to the different Nforms. Generally, trees show preference to Nsource, and most conifers prefer to NH₄⁺-N while the preference to N form of broadleaved trees is unclear. The preference may be correlated with the pHvalue of the site on which the trees grown. The trees grown on acid soil generally appear preference to NH₄⁺-N while trees grown on litmusless or alkaline soil prefer to NO₃^--N. Fungus also can alter the tree uptake characteristic to NH₄⁺-N and NO₃^--N. In some species, the NO₃^--N uptake capacity increased remarkably while uptake capacity of NH₄⁺-N keep consistent when fungus were inoculated. NH₄⁺-N and NO₃^--N have different effects on other nutrient ions uptake because of the difference charge of NH₄⁺-N and NO₃^--N. In general, NH₄⁺-N accelerates the anion absorption while inhibits cation absorption. The effects of nitrogen forms on nutrition uptake are related with not only the charge of NH₄⁺-N and NO₃^--N, but also the restrain effects among other ions. Sometimes, NH₄⁺-N inhibits NO₃^--N uptake, but the mechanism is not very clear now. The form of which nitrogen is taken up by trees will induce the change of rhizospheric pH value. Uptake of NH₄⁺-N results in the decrease of rhizospheric pHvalue. Contrary, uptake of NO₃^--N will cause the increase of rhizospheric pHvalue. The change of rhizospheric pHvalue will affect nutrient availability and thus affect nutrition uptake and utilization by trees. Trees grow differently after NH₄⁺-N and NO₃^--N uptake. When supplied with NH₄⁺-N, some confers that prefer to NH₄⁺-N grow better while a few ammonium-preference conifers hardly show the better growth. N evertheless, most plants grow better when both forms of N supplied simultaneously than either of Nsource supplied alone. For few similar studies were carried out with tree species, it needs to do more researches.

Effects of rice plants on methane emission from paddy fields

JIA Zhongjun, CAI Zucong

2003, (11):  2049-2053. 

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Methane emission from rice paddy fields is the net result of the combination of many processes, i.e., CH₄ production, CH₄ oxidation and CH₄ transportation in paddy soil. Rice plants play a key role in the CH₄ emission from paddy fields, particularly in all the processes involved. The positive and negative effects of rice plants on CH₄ emission from paddy fields are well recognized as the main factors influencing the temporal variation of CH₄ emission flux in paddy field. Process-based studies about the effects of rice plants on methane emission from paddy fields were summarized, and different roles of rice plants on this emission were discussed. Root exudates and litters of rice plants could serve as the substrate for methanogenesis and enhance the CH₄ production of paddy soils, resulting in a high CH₄ emission peak, particularly in rice late growing season. Rhizospheric CH₄ oxidation induced by rice root-excreted oxygen constitutes a main biogenic sink of CH₄, which could account for 36～90% of CH₄ produced in paddy soil over the entire growing season of rice. Up to 80% and more of CH₄ released from rice field during a growing season could be emitted by rice plant-mediated transport. The fully developed aerenchyma of rice plants could be of importance in CH₄ emission during rice growing seasons, and responsible for the CH₄ emission peak observed at rice early growing season.

Articles

Strategies and approaches of ecological and economical construction in the ecotone between agriculture and animal husbandry of North China

ZHANG Lifeng

2003, (11):  2054-2056. 

Asbtract ( 1190 )  

After a century's exploitation on agriculture, the agroecosystem in the ecotone between agriculture and animal husbandry of North China has gone on a close and consumptive state, and the soil resources has suffered from desertization, alkalization and degradation. The deterioration of soil resources and eco-environment has threatened the ecological security of the regions in Beijing, Tianjin and North China. The strategies of promoting the ecological and economical development in the ecotone should include building up an opening production structure of agriculture and animal husbandry to input artificial energy from the social system, and organizing a cooperative production on agriculture and animal husbandry by exchanging products between the close regions to gain their profits. Based on the various objectives of the local farmers and the nation in the ecological rehabilitation, and the adverse succession of the ecosystem and economics, some technological approaches for making a breakthrough of economic and ecological construction were put forward, e.g., building up a suitable pattern of arbor or shrub intercropped with artificial pasture to protect soil against wind erosion, developing vegetable production adapted to the cold climate, and raising live stocks with corn residues from agricultural zone of North China, etc..

Advances in research of biological purification of eutrophic water body

QUAN Weimin, SHEN Xinqiang, YAN Lijiao

2003, (11):  2057-2061. 

Asbtract ( 1354 )  

Eutrophication is a global problem,and the key of its controlling is to manipulate the structure of aquatic ecosystem, to recover the function of natural, healthy and stable aquatic ecosystem,and to improve the biological purification capability of eutrophic water body. Aquatic higher plant and vegetation is the most important primary producer in aquatic ecosystem,because of its large individual, long life cycle,and strong capability of absorbing nutrients. Maintaining and restoring a certain amount of aquatic plant could restrain the growth of phytoplankton, improve the biodiversity of aquatic ecosystem,and stabilize its structure. Aquatic animal plays an important role in material and energy cycles of aquatic ecosystem. Zooplankton and benthos can graze phytoplankton directly,so as to controll the number of phytoplankton. It is possible to improve the number of zooplankton by changing the structure of fish population, which might control the serious reproduction of phytoplankton, and achieve the goal of controlling eutrophication. The research of biological purification is still at its initial stage in China. In future, the following two aspects of researches should be enforced: the key technology of biologial purification of aquatic higher plant and vegetation;the new model of breed aquatics. These technologies will have a important significance to controlling eutrophication and in sustainable utilization of water body.

Advances in safety studies of soil Bt toxin proteins released from transgenic Bt crops

BAI Yaoyu, JIANG Mingxing, CHENG Jia'an, JIANG Yonghou

2003, (11):  2062-2066. 

Asbtract ( 1348 )  

Commercialized transgenic Bt (Bacillus thuringiensis) crops are permitted for field growth in a large scale, which leads to significant issues of ecological risk assessment in soil ecosystem. In this paper, some general safety problems involving in the soil Bt active toxins released from insect-resistant transgenic Bt crops in the forms of plant residues, root exudates and pollens were reviewed, including their adsorption by soil active-particles, their insecticidal activity, persistence, and biodegradation by soil microbes, and their effects on soil organisms.

Chemical behavior and ecological effects of pollutants acting on root-soil interface

WANG Meie, ZHOU Qixing, ZHANG Lihua

2003, (11):  2067-2071. 

Asbtract ( 1292 )  

Root-soil interface is the main entrance of pollutants intruding into plant tissues and the special micro-ecosphere that can result in a series of ecological safety problems. In this review, the concept of root-soil interface is presented and it is suggested that root-soil interface behavior and effects of chemical pollutants should be grouped into two aspects as rhizosphere chemical behavior and ecological effects and root chemical behavior and ecological effects.These two aspects are theoretically discussed according to the latest research advances.Rhizosphere chemical behavior and ecological effects included rhizosphere pHenvironment and adsorptive behavior, rhizosphere oxidation-reduction behavior, rhizosphere chemical toxicology effects, rhizosphere microbiological effects,and rhizosphere bioenzymatic reaction etc.,and root chemical behavior and ecological effects included root exudation, influence of enzymatic systems in roots, disturbance of normal physiological processes, change of cellular structure and function,and interference of structure and function of biological macromolecules.Particular attention should be paid to the significance as well as some problems of research on chemical behavior and ecological effects of pollutants acting root-soil interface in pollution ecology.

Solubilization and behavior of surfactants in soil

JIANG Xia, GAO Xuesheng, YING Peifeng, OU Ziqing

2003, (11):  2072-2076. 

Asbtract ( 1311 )  

Solubility increment of hydrophobic organic compounds(HOCs) is mainly caused by the presence of surfactant micelle. Soil is exposed to a considerable quantity of surfactants, even at low concentrations, and surfactants seem to significantly alter soil physicsal,chemical and biological characteristics,with sorption process playing a dominant role. In addition, plant,soil microoganism,and bio-degradation and removal of surfactant are affected by the type, structure and concentration of surfactant, their existence circumstance,and species of microorganisms.The translocation and transformation of pollutants in soil are altered by all the above reasons, which should be paid more attention.

An experimental study with bioreactor-landfill system

WANG Junqin, SHEN Dongsheng

2003, (11):  2077-2078. 

Asbtract ( 1140 )  

In this study, a methane bioreactor-landfill system was utilized to treat municipal solid waste (MSW). Through analyzing and detecting the pollutant(COD Cr) in the bioreactor-landfill system, a simulated mathematic formula of waste degradation was established. After treated with this system, the COD Cr and VFAconcentrations in MSWcould be decreased from more than20000 and 7000 mg稬^-1 to less than1500 and 200 mg稬^-1, respectively.

Articles

Respiration and production of bacterioplankton in shrimp cultural enclosure ecosystems

LIU Guocai, LI Deshang, DONG Shuanglin

2003, (11):  2079-2080. 

Asbtract ( 1302 )  

The study on the respiration and production of bacterioplankton in five shrimp cultural enclosure ecosystems showed that the production and respiration fluctuated from 90 to 909 and 248 to 1785 μgC·L^-1 ·d^-1, respectively. There existed a significant positive relationship between production and respiration. The daily P/Bratio of bacterioplancton averaged 0.93 d^-1, and its production efficiency averaged 0.34.

Nitrogen uptake and its utilization by rice in paddy field of Taihu area

SONG Yongsheng, FAN Xiaohui

2003, (11):  2081-2083. 

Asbtract ( 998 )  

The effects of different amounts and kinds of nitrogen fertilizer on rice yield and its nitrogen uptake and utilization were studied on a main paddy soil (Wushan soil) of Taihu area. The results indicated that the optimal amount of nitrogen fertilizer was about 180 kg N·hm^-2 for rice production. Applying ammonium sulfate was better than applying urea for increasing rice yield. The efficiency of nitrogen fertilizer in this experiment was about 41.8～48.5%, and its loss was 22.8～38.1%.