Table of Content

25 July 1998, Volume 9 Issue 4

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Articles

Fine root biomass and production of Castanopsis eyrei forests in Wuyi Mountains

Li Linghao, Lin Peng, Xing Xuerong

1998, 9(4):  337-340. 

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Measurements for C.eyrei forests with different stand ages in Wuyi Mountains show that in mature stand forest, the biomass, production and decomposition of fine roots were 10.645t·hm^-2, 7.3715t·hm^-2 ·yr.^-1 and 4.6775t·hm^-2 ·yr.^-1 respectively, with a yearly turnover rate of 0.69 time.The biomass and production of fine roots varied with stand age, reaching their peaks at 34 and 58 years respectively.In the mature stand forest, the Nreturn by fine root decomposition contributed 49.5% of the yearly total Nreturn, more than that by litterfall; Pand Mg returns derived from dead fine root were 42.3% and 28.9% respectively, less than those from litterfall; and Kand Ca returns were mainly came from canopy, secondly from litterfall, and only 19.3% and 9.2%, respectively from fine roots.

Carbon pool of tropical mountain rain forests in Jianfengling and effect of clear-cutting on it

Wu Zhongmin, Li Yide, Zeng Qingbo, Zhou Guangyi, Chen Bufeng, Du Zhihu, Lin Mingxian

1998, 9(4):  341-344. 

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Studies on the carbon pool of virgin and regenerated tropical mountain rain forests in Jianfengling, Hainan Island, China, and the effect of clear-cutting on it show that the total carbon pool of virgin tropical mountain rain forest was 340.467t·hm^-2, of which, the storage of plant carbon, soil organic carbon and litter layer carbon accounted for 232.791, 104.696 and 2.98t·hm^-2, respectively.The total carbon pool of regenerated tropical mountain rain forest was 258.996t·hm^-2, of which, the storage of plant carbon, soil organic carbon and litter layer carbon accounted for 150.203, 105.803 and 2.99t·hm^-2, respectively.Clear-cutting could cause the decrease of carbon storage of forest soil, and natural regeneration could make the carbon storage recover fast.After clear-cutting, the total carbon pool of 26-year-old natural regenerated forest was only 76% of that of the virgin forest.

Crown characteristics and spatial distribution of leaves of new poplar clones

Li Huogen, Huang Minren

1998, 9(4):  345-348. 

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The crown characteristics of eleven five years old black poplar hybrid clones were explored.No significant difference of crown characteristics was found among clones, but great difference existed among different layers and parts within the crown.The difference of the vertical distribution of foliage was greatly attributed to leaf size, while for the horizontal variation of foliage, the leaf number played a great part.The general distribution pattern of crown in population was that the leaf area increased from upper to lower and from inner to outer within the crown.

Gap regeneration in a broadleaved-Korean pine forest in Changbai Mountain Natural Reserve

Zang Runguo, Guo Zhongling, Gao Wentao

1998, 9(4):  349-353. 

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Through comparing the quantitative characteristics of tree species composition in gap and non gap stands, this paper studied the response of main tree species to gap regeneration in the broadleaved-Korean pine forest in Changbai Mountain Natural Reserve, and expounded the role of gaps in maintaining the structure and diversity of the forest.With the alternation of gaps and non gaps in the broadleaved-Korean pine forest, the relative dominance of Korean pine vs.broadleaved trees, and of canopy layer trees vs.subcanopy and understorey layer trees changed alternatively.Gaps enhanced the species richness, increased the species diversity, made the coexistence of different species be possible, and thereby, maintained the stability of the whole broadleaved-Korean pine forest.

Variation of respiratory enzyme activities of Suaeda salsa seedlings under salinity and doubled CO₂

Liu Jiayao, Yi Yanjun, Bai Kezhi, Liang Zheng

1998, 9(4):  354-358. 

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Studies on the response of respiratory enzyme activities of halophyte Suaeda salsa seedlings growing under normal (350μl·L^-1) and doubled (700μl·L^-1) concentrations of CO₂ to KCl and NaCl show that under normal and doubled concentrations of CO₂, the activities of succinic dehydrogenase(SDH), malic dehydrogenase (MDH), Cytocrome Coxidase (CO), glycolate oxidase (GO) and hydroxypyruvate reductase (HPR) were inhibited by 300mmol·L^-1 KCl and NaCl;the activity of isocitric dehydrogenase (IDH) was decreased by NaCl, but increased by KCl.The operation rate of tricarboxylic acid cycle (TCAC) was deceleratedby CO₂ under KCl stress, but accelerated under NaCl salinity.The steps of limiting speed by TCAC's operation was not related with MDH.COis the important site of salt affecting respiratory metabolism.Moreover, the influence of K⁺ on protein expression was different from that of Na⁺, and CO₂ could reduce the protein expression of Suaeda salsa seedlings under NaCl and KCl stresses.

Comparative study on structure characteristics of hilly latored soils under different vegetation in south subtropics

Zhong Jihong, Tan Jun, Guo Qingrong, Luo Bosheng, Zhou Muning, Huang Xianglan

1998, 9(4):  359-364. 

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The study shows that with the backward succession of vegetation, the latored soils suffered structural degradation, which was characterized by the sandification of surface layer with relatively increasing content of sand grains and decreasing content of clay grains, the lowering aggregate stability with decreasing water stable aggregates and the deteriorating soil porosity with increasing bulk density and lowering large pore content.For natural latored soil, the increasing bulk density and the decreasing large pore content were more obvious, but for cultivated one, the lowering structural stability and sandification of surface layer were more serious.It is also indicated that the decrease of soil organic matter content caused by vegetation deterioration was the main interior factor causing the structural degradation of latored soils.

Simulation of soil organic carbon dynamic after changing landuse pattern in hilly red soil region

Li Zhongpei, Wang Xiaoju

1998, 9(4):  365-370. 

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Double component model was used to simulate the soil organic carbon dynamics after changing landuse pattern in hilly red soil region of subtropical China, and investigation and monitoring data were used to evaluate it.The model distinguished soil organic carbon into two compartments, i.e.newly formed organic carbon and native organic carbon.The transformation of each kind of organic carbon was described by the first-order kinetics function, and the changing process of soil organic carbon storage in four landuse patterns of masson pine forest, slash pine forest, citrus orchard and pasture since natural subtropical soils being reclaimed for 10 years was simulated.The results show that this method fits to simulate the dynamic process of soil organic carbon storage during the early stage of changing landuse patterns with different soil types.

Soil conditions of forest-fitting land along river banks in semiarid region

Liu Mingguo, Han Hongyun, Liu Xiaoyi

1998, 9(4):  371-375. 

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Basic soil properties of forest-fitting land along river banks in semiarid region were studied with correspondence and multiple regression analyses, which showed that soil physical and chemical properties were mainly affected by soil texture.The organic matter content, CaCO₃ content, conductivity and field water-holding capacity were positively correlated with the content of medium and fine particles in soil mechanical composition.The dominant factors affecting forest growth were soil texture, underground water level, and available soil depth, and the last two factors were classified by means of optimal cutting method.In considering of the local specific conditions with the grading combination of the dominant factors, the forest-fitting land along river banks was classified into 20 site types, and the site quality was comprehensively evaluated by multiple species.

A preliminary evaluation on management models of agroforestry system on low hills in Hubei Province

Yu Fengan, Peng Zhenhua, Jiang Zehui

1998, 9(4):  376-378. 

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Eleven agroforestry systems established on low hills in Hubei Province were preliminarily evaluated by a modified AHPmethod.The results show that among the 11 systems, the mixed bamboo-Chinese fir forest intercropped with beans had the highest comprehensive benefit, followed by bamboo intercropped with beans, masson pine intercropped with tea and maize, chestnut intercropped with wolfberry and beans, tea intercropped with maize, and orange intercropped with maize and beans.

Geographic differentiation of yield increase efficiency caused by recycled nutrients in agro ecosystems

Shen Shanmin, Yin Xiuyan, Yu Wantai, Zhang Lu, Chen Xin, Liu Hongxiang, Wang Delu, Wang Kairong, Zhou Weijun, Xie Xiaoli

1998, 9(4):  379-385. 

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The results of field experiments at four stations in different parts of China indicate that the crop yield increment caused by recycled nutrients within an agricultural ecosystem was significantly influenced by the thermal condition of climate, the application of fertilizers and the duration of the experiments lasted.In the case of no fertilizer, the average crop yield increment caused by recycled nutrients with a 0.8 recycling rate ranged from 253kg·hm^-2 (average of ten years) at Hailun station (in temperate zone) to 1122kg·hm^-2 (six years) at Shenyang station and 1332kg·hm^-2 (eight years) at Kezuo Xiahetao station (in warmer-temperate zone), and to 2884kg·hm^-2 (seven years) at Taoyuan station (in subtropical zone), while on the base of applying Nand Pfertilizers, the corresponding increments at the four stations were 225, 694, 786 and 1321kg·hm^-2 respectively.There was a marked accumulative residual effect of recycled nutrients in farmyard manure on crop yields, based on N, Pand Kfertilizers, the average increase rate of crop yields caused by recycled manure was about 5% in the first three years, but raised up to about 14% in the last three years within the experimental period.

Contribution of fertilization development in food production and its geographic differentiation

Shen Shanmin, Yu Wantai, Chen Xin, Zhang Lu, Liu Hongxiang, Wang Delu, Wang Kairong, Zhou Weijun, Xie Xiaoli

1998, 9(4):  386-390. 

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Long-term field trials on eight simulated models representing the fundamental types of fertilization system in China have been carried out from north to south at three field stations in the eastern humid region of China.The results indicate that the contribution of fertilization to crop yield was significantly influenced by the fertilization system adopted and the thermal condition of local climate.In the case of optimum fertilization system, the largest contribution rate was 30%(average of ten years) at Hailun station (temperate zone), 38%(six years) at Shenyang station (warmer temperate zone) and 44% (seven years) at Taoyuan station (subtropical zone), impling the existence of geographic differentiation controlled by the thermal factor of climate.Therefore, the largest contribution rate of fertilization in the forming of crop yield can be generally estimated from 30% to 45%, depending on the climate condition and with no change of other techniques adopted in farming.

Features of Lake Tuo ecosystem and ecological safeguard of lakeside farmlands

He fang, Xiang Chengsheng

1998, 9(4):  391-394. 

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Through the investigation and analysis of the features of Lake Tuo ecosystem, the interactions between the lakes of river vestiged low-lying land type along the banks of Huaihe River and the lakeside farmland ecosystems were studied.In order to maintain the ecological balance and the sustainable use of resources in Lake Tuo, measures were put forward to safeguard the farmland system and the soils along the lakeside.

Physioecological study on high yielding cultivation of rice by dry-raising seedling and thin spacing transplanting techniques ⅡHigh-yielding formation and its physiobiochemical properties of early rice

Lin Wenxiong, Wang Songliang, Liang Yiyuan, Guo Yuchun, He Shuilin, Zheng Luduan, Weng Dinghe, Hong Laishui, Pan Zhengxian

1998, 9(4):  395-399. 

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The study shows that after transplantation, the dry-raising seedlings still kept high physiobiochemical vigor.From tillering to milky stage, the dry-raising plants had higher activities of ascorbate oxidase, superoxide dismutase, peroxidase, catalase, ATPase and nitrate reductase, but lower content of malondialdehyde and lower membrane permeability than the wet raising plants, indicating that dry-raising plants had a strong adversity-resistance, and thereby, they could turn green fast, tiller early, have a high productive tiller rate, keep their leaves to grow for a longer period of time, and have more dry matter accumulation and high yield.

Diapause of first generation adults of rice water weevil in double cropping rice area

Zhai Baoping, Shang Hanwu, Cheng Jiaan, Huang Enyou, Zheng Xuehao

1998, 9(4):  400-404. 

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Studies on the summer population of rice water weevil (Lissorhoptrus oryzophilus) in double cropping rice area of Zhejiang Province indicated that food condition rather than air and soil temperature or day length was the main stimuli of summer diapause of the first generation adults.Under natural conditions, the first generation adults in early rice fields never changed their reproductive diapause status even if they were caged in the paddy.However, if feeding on rice seedlings, first generation adults both newly emerged and in reproductive diapause status would normally develop their ovaries, and the reproductive diapause of the aestivating first generation adults would be over.Meanwhile, the newly emerged and the aestivating adults would develop their ovaries and flight muscles simultaneously.If the food condition was kept, their flight muscles would degenerate and oviposition would be seen.

Interactive effect of compound damages by multi-pests in cotton field and application of compound control indicators for “two red pests”

Wang Ruiqi, Zhang Shifu, Fan Xiaoxian, Huang Minsong, Wan Peng, Shi Shangbo

1998, 9(4):  405-410. 

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To counter the compound damage by multi-pests in the cotton-producing area of central Yangtze River banks, a compound damage system of six species of pests with three combinations was designed.The damage of multi-pests on cotton and their interactive effect were quantitatively described by path analysis.The analysis for direct and indirect effects of multi-pests on cotton yield and its quality indicated that the interaction of pests on the damage of cotton plants was positive or negative.On the basis of these, the dynamic control indicators of compound damage for two red pests (Pectinophora gossypiella and Tetranychus cinnabarinus) were formulated, which were demonstrated to have notable economic, ecological and social benefits by experiment and expansion.

Diversity of aquatic beetles in mountainous regions of northeastern China

Wang Miao, Ji Lanzhu, Zhao Ming, Li Qiurong, Chen Xin

1998, 9(4):  411-415. 

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Investigations on aquatic beetles in static water bodies of Changbai Mountains Nature Reserve and Yiwulushan Mountains show that the species diversity of aquatic beetles is richer in broadleaved-Korean pine forest ecosystem of Changbai Mountains than in agroforestry ecosystem of Yiwulushan Mountains.There are 17 genera and 29 species of aquatic beetles in Changbai Mountains, but only 10 genera and 13 species in Yiwulushan Mounatins.The Shannon diversity index is respectively 2.214 and 1.643 in Changbai Mountains and Yiwulushan Mountains, and the Shannon evenness is 1.260 and 0.640, respectively.The species abundance distribution of aquatic beetles in these two different ecosystems is fitted to logarithmic series distribution.Asmall number of species become the dominant in the two ecosystems.In Changbai Mountains, the dominant species are Hydroglyphus pusillus, Haliplus simplex, and H.pusillus, andin Yiwulushan Mountains, they are Agabus ussuriensis and A.brandti .

Predation of Monomorium pharaonis on Nilaparvata lugens

Xu Xiaofeng, Cheng Xianian, Zou Yunding

1998, 9(4):  416-418. 

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The predation of Monomorium pharaonis on the brown planthopper (Nilaparvata lugens) was reported for the first time in this paper.The results of predation experiment conducted both in rearing cage and in big test tube showed that M.pharaonis had a strong predation effect on nymphs of brown planthopper, especially on young nymphs, with an average predation rate of 93% and 30%, respectively.The functional reaction of predation belonged to the Holling IIreaction, and the predation was significantly promoted by the resistance of the host rice varieties.

Effect of soil nematode exclusion on wheat growth and its N and P uptake

Hu Feng, Li Huixin, Wu Xinqi, Wu Shanmei

1998, 9(4):  419-424. 

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The soil used for pot experiment was treated by a nematocide (phenamiphos, 67mg·kg^-1 dry soil) or dry heating at 105℃ for 2h before wheat (Triticum aestivum) planting to study the effect of these two treatments on wheat growth and its Nand Puptake.Approximately 80% of the nematodes in soil were eliminated by nematocide and 100% by dry heating.Significantly lower wheat biomass was found in nematocide treatment than in control from seedling to heading stage.The same was true for plant Ncontent from jointing to ripening stage, Nuptake in whole growing season, and Puptake from heading to ripening stage.In dry heating treatment, wheat biomass, Ncontent and Nand Puptake were also markedly lower than control from heading to ripening stage.The aboveground biomass and its Nand Puptake had a similar tendency with those of whole plant for the two treatments.However, nematode exclusion had little effect on plant Pcontent.The inhibitory effect of nematode exclusion on wheat growth and its nutrient uptake was suggested to be associated with the reduce of Nmineralization and of plant growth promoting substance derived from soil microbial activities.

Comparative study on remedy ways of saline-alkali grassland in Songnen Plain

Guo Jixun, Jiang Shicheng, Sun Gang

1998, 9(4):  425-428. 

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This study was designed to compare the biological, chemical and physical remedies on saline-alkali grassland.Three kinds of forage grass, Aneurolepidium chinense, Hordeum brevisubulatum and Puccinellia tenuiflora were planted in experimental sites, and soil was ameliorated with grass litter, gypsum amendment and sand bedding, respectively.The result showed that all of the three ways decreased soil pHand electrical conductivity, and increased soil water content.In biological treatment.Aneurolepidium chinense and Hordeum brevisubulatum could grow well with 1.5kg·m^-2 of litter, and Puccinellia tenuiflora with 1.0kg·m^-2 of litter.Applying 1.25kg·m^-2 of gypsum could produce an efficient effect.A.chinense and H.brevisubulatum could normally grow with 13cm thickness of sand bedding, and P.tenuiflora with 11cm.

Obstacles of soybean continuous cropping Ⅱ Mechanism of soybean yield decline and control strategies for toxin of Penicillium purpurogenum in soils

Hu Jiangchun, Xue Delin, Wang Shujin

1998, 9(4):  429-434. 

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Analysis on the harmfulness of toxin produced by Penicillium purpurogenum in soil in the whole growth and development period of continuous cropping soybean shows that the toxicity began at the stage of seed germination.At the seedling and branching stages, high toxin concentration (1000 delution folds) could entirely result in non-nodulation, and even low concentration (100000 delution folds) could still inhibit 40% of nodulation, resulting in an obvious decrease of photosynthetic and nitrogen-fixing capacities of continuous cropping soybean.By stimulating the growth of P.purpurogenum, the root residue and litter of soybean could cause further harmfulness of soybean.Studies on controlling toxin of P.purpurogenum in soils of continuous cropping soybean show that soil actinomyces MBantibiotic control could make continuous cropping soybean have a yield increase of 8.4～18.9%; and marine actinomyces MB-97 biotic control could make a yield increase of 30.5%.With the application of MB 97 bio fertilizer and comprehensive control on disease precaution and toxicity reduce in the whole growth and development period of continuous cropping soybean, the yield of continuous cropping for 5years in micro-plot field experiment could reach 4575kg·hm^-2 .

Effect of mulching cultivation with plastic film on soil microbial population and biological activity

Chen Xishi, Guo Shufan, Wang Jingkuan, Zhang Jian

1998, 9(4):  435-439. 

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Studies on the soil microbial population and biological activity in a brown earth continuously planted with corn and covered with plastic film show that after long-term mulching, the numbers of bacteria, actinomyces and fungi in the topsoil increased 22.6%, 29.3% and 19.7 %, respectively.At seedling stage, bacteria increased by 21.4%; at elongating and ripening stages, actinomyces increased by 22.4% and 24.4%, respectively; and within the whole growth period, fungi increased 12.2～14.6%.In addition, the dominant facultative anaerobial populations of bacteria tended to be increased, but those of fungi were not to be changed.Soil respiration rate was also enhanced by mulching in all sites with different fertility, but soil urease activity only increased obviously in the site with high fertility.

Optimized conditions for protoplast formation and regeneration of Aspergillus ficuum

Wan Xiaochun, Li Ping, Ding Xiaolin, Tao Wenyi

1998, 9(4):  440-442. 

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Orthogonal experiments were designed to study the optimized conditions for protoplast formation of Aspergillus ficuum .A 1% mixed solution of enzymes (0.5% cellulase + 0.25% snail enzyme + 0.25% lysozyme) was used to treat the body cells of A.ficuum, and the yield of protoplast was up to 3.2 × 10⁷ individuals·ml^-1 .The optimum osmotic stabilizer was 0.6 mol·L^-1 KCl containing 0.2 mol·L^-1 PO₄³⁺ (pH5.8), and the optimum duration and optimum temperature for enzymatic action was 3.0h and 30℃, respectively.The optimal conditions for protoplast regeneration were also obtatined, and the regeneration rate was over 30%.

Watershed ecology—New discipline, new idea and new approach

Deng Hongbing, Wang Qingli, Cai Qinghua

1998, 9(4):  443-449. 

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Based on the deliberation of the definition, origination and relative knowledge of watershed ecology, the scientific significance and major research contents of watershed ecology as a discipline were discussed in this paper.It is suggested that the study and application of watershed ecology should be an effective approach to the sustainable development of society and economics in certain watersheds, and that it is necessary to develop a systematic research on watershed ecology as soon as possible.