Table of Content

15 August 2003, Volume 14 Issue 8

Previous Issue    Next Issue

Optimization of spatial arrangements and patterns for shelterbelts or windbreaks

ZHU Jiaojun, JIANG Fengqi, FAN Zhiping, ZHOU Xinhua

2003, (8):  1205-1212. 

Asbtract ( 0 )  

Spatial arrangements and patterns of shelterbelts or windbreaks are the key factors influencing the shelterbelt structures, shelter benefits, and shelterbelt sustainability. In order to keep the shelter benefits and achieve the sustainability of shelterbelts, it is necessary to keep the reasonable arrangements and patterns in spatiality and the continuation in time. Based on the investigations on the shelterbelts, which were established in1992 as the models in Shuangjingzi Township, Changtu County, Liaoning Province, and combined with the experiences and practices of shelterbelt management, the authors studied and summarized the arrangements and patterns of shelterbelts, which included the direction of a single shelterbelt and shelterbelt networks, the arrangement of tree composition in a shelterbelt, and the mixture of tree species for shelterbelts. Additionally, the spacing intervals between shelterbelt and the spatial patterns for regional shelterbelts were also discussed. The results indicated that the direction of both single shelterbelt and shelterbelt networks should be perpendicular to the disaster winds. It is better for the structure of a shelterbelt to arrange the trees in triangle form in a shelterbelt. According to the edge effect, the tree species which grow slowly should be arranged in the edge lines, but the tree species which grow fast should be arranged in the inner lines of the mixed shelterbelts. Optimal spacing intervals between windbreaks could be predicted from the indices of a given windbreak structure (porosity), percentage of desired wind speed reduction, and tree growth model (model for determining initial protective maturity age). The patterns of shelterbelts in large scale should be evaluated and arranged according to the principles of landscape ecology. The results mentioned above would provide the evidences for shelterbelt sustainable management.

Relationship between photo-inhibition of photosynthesis and reactive oxygen species in leaves of poplars suffering root osmotic stress

FENG Yulong, ZHANG Yajie, ZHU Chunquan

2003, (8):  1213-1217. 

Asbtract ( 0 )  

To know more about the photo inhibition of photosynthesis under field conditions, its relationship with reactive oxygen species (ROS) in leaves of poplar clone seedlings was studied under osmotic stress conditions. With the increasing duration of osmotic stress and the enhancement of stress intensity, the ROSlevel, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity increased, while the activities of catalase (CAT) and ascorbate peroxidase (APX) decreased, resulted in the unbalanced ROSmetabolism and intensified photo inhibition. The inhibition of SODactivity by copper diethyldithiocarbamate or the accelerated generation of O₂^ˉ. with methyl viologen (MV) could also induce the photo inhibition. The decrease of the ability of poplar clone seedlings in scavenging H₂O₂ under osmotic conditions limited the dissipation of excess light energy and the role of photosynthetic apparatus in protecting against photo inhibition through Mehler reaction. Photo inhibition might be related to the accumulation of ROS.

Effects of ultraviolet-C irradiation on membrane lipid peroxidation and activity of PSⅡ electron transport in chloroplasts of Taxus cuspidata needles

DU Yingjun, JIANG Ping, WANG Bing, SHI Yi

2003, (8):  1218-1222. 

Asbtract ( 0 )  

The isolated chloroplasts of Taxus cuspidata needles treated with 12 W·m^-2 of ultraviolet C (UV-C, 254 nm) irradiation were studied under laboratory conditions. The results showed that with the increase of UV-C irradiation, the carotenoids (Car) and glutathione (GSH) contents and superoxide dismutase (SOD) activity were decreased, while the malondialdehyde content (MDA) and the relative permeability of chloroplasts membrane were increased to various extents. The PSⅡ electron transport activity was conspicuous decreased, which had a significant inverse ratio with photosynthetically active radiation(PAR). UV-C irradiation was insensitive on chlorophyll. The results indicated that membrane lipid peroxidation of chloroplasts caused by UV-C radiation was the reason of the decrease of PSⅡelectron transport activity.

A preliminary study on the chemical properties of precipitation, throughfall, stemflow and surface run-off in major forest types at Dinghushan under acid deposition

LIU Juxiu, ZHANG Deqiang, ZHOU Guoyi, WEN Dazhi, ZHANG Qianmei

2003, (8):  1223-1228. 

Asbtract ( 0 )  

Studies on the chemical properties of precipitation, throughfall, stemflow and surface run off in major forest types at Dinghushan under acid deposition showed that the pHvalue of precipitation was about 4.90,and the frequency of acid rain was over 62%. In broad leaved forest, the pHvalue of precipitation was lower than that of throughfall, but higher than that of stemflow and especially the surface run off, indicating that the soil was naturally acidified. In mixed forest, both throughfall and surface run off had a higher pHvalue,but stemflow had a lower pHvalue than precipitation. The throughfall and stemflow were more acidified than precipitation in coniferous pine forest, but the surface run off had a higher pHvalue than precipitation. These results suggested that among the three major forest types at Dinghushan,the canopy of broad leaved forest had the highest buffering ability,whereas for the soil,the coniferous forest had the highest soil buffering capacity. The concentrations of nutrient elements, such as P, K, Ca, Na and Mg in the throughfall, stemflow and surface run off were higher than those in bulk precipitation in all forests at Dinghushan, some even 10 times higher, indicating that a large amount of nutrients were leached from the canopy. The concentrations of nutrient elements in stemflow were higher than those in throughfall in all forests, and the concentration of nutrient elements in surface water was higher than those in atmospheric rainfall. Coniferous forest had a higher concentration of nutrients in the throughfall and stemflow and a lower nutrient concentration in the surface run off than other forest types,which implied that nutrient loss was more serious in broad leaved and mixed forests than in coniferous forests.

Method for measurement of optical stratification porosity (OSP) and its application in studies of management for secondary forests

ZHU Jiaojun

2003, (8):  1229-1233. 

Asbtract ( 0 )  

Secondary forest is the main body of forests in China, and hence, its management plays a very important role in the projects of natural forest conservation and ecological environment construction in this country. The structure, especially the vertical stratification structure of secondary forest is one of the key factors in the management of secondary forest, and can be considered as the base of its management. Based on previous studies, the concept of stratification porosity was introduced, and the optical stratification porosity (OSP), which is the two dimensional alternative measurement of stratification porosity, could be used to represent the vertical stratification structure of secondary forest. The method using hemispherical photographic silhouette (photographic silhouette taken with fisheye lens) to estimate the OSPof a forest stand was also introduced. In addition, the possible applications of OSPin studies on the structure and restoration ecology of secondary forest, and the theory and techniques for the management of secondary forest were also given in this paper.

Effects of soil temperature and moisture on soil respiration in different forest types in Changbai Mountain.

WANG Miao, JI Lanzhu, LI Qiurong, LIU Yanqiu

2003, (8):  1234-1238. 

Asbtract ( 0 )  

The effects of soil temperature (0, 5, 15, 25, 35 ℃) and water content on soil respiration in three forest types in Changbai Mountain were evaluated in laboratory condition. The results indicated that the soil respiration rate was positively correlated to soil temperature from 0 to 35 ℃ and it increased with soil water content from 0.21 to 0.37 kg·kg^-1. The soil respiration rate decreased with soil water content when water content was over the range. The result suggested the interactive effects of temperature and water content on soil respiration. There were significant differences in soil respiration among the various forest types and the highest was in broad leaf Korean pine forest, then in erman's birch forest, and it was the lowest in dark coniferous forest. The optimal condition for soil respiration in broad leaved Korean pine forest was at 35 ℃ under 0.37 kg·kg^-1 water content, and it was at 25 ℃ under 0.21 kg·kg^-1 in dark coniferous forest and at 35 ℃ under 0.37 kg·kg^-1 water content in erman's birch forest. Because the forests of broad leaf Korean pine, dark coniferous and erman's birch are located at various altitudes, the soil temperatures had 4～5 ℃ variation in different forest types during the same period. The soil respiration rates measured in brown pine mountain soil were lower than those in dark brown forest and they were higher in mountain grass forest soil than those in brown pine mountain soil.

Quantitative simulation on the vertical distribution of soil organic matters in mountainous soil profiles in the subtropical area, south China

CHEN Qingqiang, SHEN Chengde, SUN Yanmin, YI Weixi, JIANG Mantao, PENG Shaolin, LI Zhi'an

2003, (8):  1239-1245. 

Asbtract ( 0 )  

Quantitative descriptions of soil organic matter (SOM) dynamics, i.e., their distribution, turnover and movement, are essential for the running of the simulation of terrestrial ecosystem organic matter models. In this study, based on utilizing SOM diffusion translation decomposition model,two soil profiles were selected in different vegetation zones at Dinghushan Mountain for quantitative studies on SOMdynamics and their controlling factors. SOM were divided into three kinds of compartments: rapid compartment with turnover rate of 0.1～1·yr^-1, slow compartment with turnover rate of 0.002～0.02·yr^-1, and stable compartment with turnover rate of 0.0001～0.001·yr^-1. The numerical results suggested that SOM distribution in soil profile in subtropical mountainous areas of south China obeyed the law of diffusion motion, translation motion and decomposition. The turnover rate of SOM rapid compartment was 0.483·yr^-1 in the forest vegetation zone, and was 0.694·yr^-1 in the shrub vegetation zone. The turnover rates of SOM slow compartment in the two kinds of vegetation zones were both 0.02·yr^-1, and the turnover rates of SOM stable compartment in the two kinds of vegetation zones were both 0.001·yr^-1. SOM diffusion rate and translation rate for the forest vegetation zone was 4 cm²·yr^-1 and 0.2 mm·yr^-1, respectively, and the two rates of the shrub vegetation zone were 1 cm²·yr^-1 and 0.5 mm·yr^-1, respectively. The obvious discrepancy between numerical values and measuring values for SOM content occurred in the 0～10 cm sections of the profiles, which might be due to the fact that the upper sections were at the interface between lithosphere and atmosphere, and were influenced directly by changes of climatic and environmental factors. The two kinds of values for SOM content were identical below the upper section of the profiles, and it indicated stable pedogenesis environments. Diffusion motion had obvious influences on SOM vertical distribution, and translation motion had clear impacts on SOM distribution only in the upper 0～10 cm section. Comparison analysis suggested that SOM dynamics were controlled mainly by soil profile qualities such as SOM content, clay content, soil fabric, void types and their developments, soil fauna and microorganism activities, etc. With the increasing of primary production of aboveground vegetation, the turnover rate of SOM rapid compartment decreased and SOM content increased, which provided scientific basis for increasing soil carbon sink through anthropogenic effects.

Ecological distribution of soil microorganism in artificial greenbelt in hinterland of Takilimakan Desert and their relations with soil factors

ZHOU Zhibin, LI Peijun

2003, (8):  1246-1250. 

Asbtract ( 0 )  

Studies on the distribution of soil microorganisms in the artificial greenbelt in hinterland of Takilimakan Desert and the effects of soil features on the distribution showed that under saline water irrigation, the activities of soil microorganisms increased sharply, and the soil structure and nutrient status were improved. Among soil microorganisms, bacteria were predominant, actinomyces were the next, and fungi were the least. There were more microorganisms in upper than in deeper soil layers. Soil microorganisms near shelter-forest had a higher activity, and their quantities over 3m from shelter-forest were almost equal to those in shifting sand. The quantities of soil microorganisms varied with seasons, and there were distinct differences among different sites of forests. Among the measured 11 soil factors, the interactions between pairs of soil available phosphorus available potassium, organic matter available potassium, available nitrogen available potassium, available nitrogen available phosphorus, organic matter-available phosphorus, available phosphorus available nitrogen, total nitrogen available potassium, available potassium available phosphorus, total nitrogen available phosphorus, and water contents available nitrogen were significant, with the correlation coefficients of 1.37～2.58. The direct effects of available phosphorus, available nitrogen, and total nitrogen on the microbial quantity were significant, with the coefficient of 1.01～2.58.

Dynamics of soil inorganic nitrogen in middle mountain moist evergreen broadleaf forest under different disturbance intensities in Ailao Mountain

LI Guicai, HAN Xingguo, HUANG Jianhui, WAMG Changyao

2003, (8):  1251-1256. 

Asbtract ( 0 )  

The effects of three different intensities of disturbance on soil NH₄⁺-N and NO₃^--N contents were studied in three community types (primary Lithocarpus xylocarpus forest, secondary oak forest,and tea plantation, which represent three different intensities of disturbance). The results showed that the contents of inorganic nitrogen in soil (0～15 cm) of three community types had marked differences.Soil organic matter and total nitrogen decreased, while C/Nratio increased,with the increasing intensity of the disturbance. Simultaneously, the potential lose of NO₃^--N increased. It suggested that the disturbance was not in favor of the retainment of soil fertility and the positive development of community succession. The soil organic matter, total nitrogen and C/N ratio were basically same at different spatial sites in same community, while the NO₃^--N contents were obvious difference. This implied that soil NO₃^--N content was less stable than NH₄⁺-N. In addition, NH₄⁺-N was the major component of the soil inorganic nitrogen, accounted for 95.5%～99.3% of the total content of soil inorganic nitrogen.

Properties of potassium loss from red soil slope land in different farming systems

YUAN Donghai, WANG Zhaoqian, CHEN Xin, GUO Xinbo, ZHANG Ruliang

2003, (8):  1257-1260. 

Asbtract ( 0 )  

The properties of potassium loss in red soil slope field under six cultivations were studied. The results showed that potassium lost mainly with bed load and runoff on surface of soil. The potassium lost mostly with runoff in slope field under contour, contour dam cultivated ways with less sediment except the fallow, under which the loss of potassium with bed load equaled to the loss of potassium with runoff. The potassium lost mostly with bed load in slope field under straight, grass strip and contour ditch cultivated ways with more sediment, and particulate potassium was the main form of potassium lost in runoff. Compared with straight cultivated way, other cultivated ways reduced soil potassium loss significantly. Contour, fallow, and contour dam cultivated ways were better than straight and grass stripe cultivated ways on controlling potassium loss. In the year of 2000, the potassium loss was mainly occurred during May to August accounting for 87.24～100% of total annual lost.

Effect of sulfur fertilization on yield production and sulfur content of crops and pasture in north China

CUI Yanshan, WANG Qingren

2003, (8):  1261-1264. 

Asbtract ( 0 )  

Pot experiment on 3 crops (wheat, corn, oilseed rape) and a pasture (clover) under 5 levels (0, 5, 10, 20, 40 mg·kg^-1) of sulfur (S) was carried out to study Sapplication on yield production, Scontents and their relationship of these crops. The results showed that under Sapplication, the biomass of four plants increased by 5～32%, and the grain yield increased by 3～20%. The contents of Svaried with different corps, for example, the content of Sin the oilseed rape was the highest (0.479～1.228%), and that in corn was the lowest (only 0.043～0.091%). The contents of Sin different plant parts of the same crop had a positive correlation with content of Sapplication. Both the biomass and grain yield for all the crops except the clover had a close correlation with the content of Sapplication. With available Sin the soils increased, the amount of Sabsorbed by crops was increased at the beginning, and then decreased after reached the peak.

NO₃^--N leaching and distribution in soil profile in dry highland of Loess Plateau under long-term fertilization

DANG Tinghui, GUO Shengli, FAN Jun, HAO Mingde

2003, (8):  1265-1268. 

Asbtract ( 0 )  

The NO₃^--N accumulation and distribution in soil profile of Loess Plateau dry highland were studied by long term field trials. The results showed that NO₃^--N was accumulated in the soil profile under N fertilization. Application of Pfertilizer or organic manure reduced the NO₃^--N content and its leaching depth in the soil profile. The deepest depth of NO₃^--N accumulation was 120～200 cm under N treatment, and the peak of the accumulation was the highest in NPMtreatment, with the depth of 60～120 cm. The NO₃^--N accumulation depth was 80～140 cm for NP. Without nitrogen application, there was no evident accumulation of NO₃^--N in soil profile. The more nitrogen used, the more NO₃^--N accumulated in soil profile. Under the same nitrogen application rate, NO₃^--N accumulation might decrease with increasing Papplication.

Decomposing effect of chemical-biological decomposing combined technique on rice straw and its fourier transform infrared spectroscopy

CAI Yanfei, LIAO Zongwen, WANG Dehan, LI Yurui

2003, (8):  1269-1272. 

Asbtract ( 0 )  

The effects of several chemical biological combined decomposing techniques (CBCDT) on the decomposition of rice straw were studied by fourier transform infrared spectroscopy (FTIR). The results showed that under CBCDT treatments, rice straw could be better decomposed than in control. After seven days under CBCDT treatments, the straw turned into brown, and was easy to be broken down and obviously decomposed. FTIRspectra indicated that under chemical agent Abiological agent Acombined treatment, hydroxyl, ketonic carbonyl, methyl, methylene, methane and aliphatic compounds decreased, proteins and amino acids completely decomposed, but aromatic compounds (specially substituted group) increased, and hence, the humification of straw was accelerated.The effects of different decomposing agents on straw were decreased in the order of chemical degrade agent A>chemical degrade agent B, biological degrade agent A> biological degrade agent B> biological degrade agent C. The chemical agent Abiological agent Acombined treatment was the most effective among several treatments.

Effect of different cultivation practices on Fe and Cd content in iron plaque outside rice root and Cd content in rice root

SHI Kun, ZHANG Fusuo, LIU Xuejun, ZHANG Xudong

2003, (8):  1273-1277. 

Asbtract ( 0 )  

The effects of different cultivation practices-traditional flooding (TF), film mulching (FM), straw mulching (SM), and wetting cultivation (WC)-on Cd-concentrations in Indica and Japonica roots and on Cd and Fe concentrations in iron plaque outside the roots were studied at different growth stages (tillering, booting, filling and harvest) with a Cd polluted soil. The results showed that in all practices, the mean Fe concentration in iron plaque and the mean Cd concentration in roots of Japonica at tillering stage were 6.37 mg穖g^-1 and 25.49 mg穔g^-1, and greater than those of Indica, which were 4.52 mg穖g^-1 and 16.37 mg穔g^-1 respectively ; at booting stage, the mean Fe and Cd concentrations in iron plaque and the mean Cd concentrations of Japonica were 1.60,16.35 and 54.68 mg穔g^-1, and greater than those of Indica, which were 1.06 mg穖g^-1, 9.56 and 43.31 mg穔g^-1, respectively; at filling stage, the Fe concentrations in iron plaque of Japonica in SM and WC were 0.89 and 1.00 mg穖g^-1, and those of Indica were 0.63 and 0.30 mg穖g^-1 ; in all practices, the mean Cd concentrations in iron plaque and root of Japonica were 15.23 and 73.68 mg穔g^-1, and those of Indica were 3.46 and 52.38 mg穔g^-1 ; at harvest stage, the Fe concentration in iron plaque of Indica in TFwas 1.21 mg穖g^-1 and that of Japonica was 0.65 mg穖g^-1, but that of Japonica in SM was 0.94 mg穖g^-1 and that of Indica in SM was 0.55 mg穖g^-1 ; the Cd concentration in iron plaque of Japonica in WC was 7.96 mg穔g^-1,and that of Indica was 5.09 mg穔g^-1 ;the mean Cd concentration in root of Japonica was 54.53 mg穔g^-1 and that of Indica was 35.91 mg穔g^-1 in all practices.

Effects of rhizobia on morphological distribution of Cu, Zn and Cd in soil

CHEN Wenli, HUANG Qiaoyun, GUO Xuejun

2003, (8):  1278-1282. 

Asbtract ( 0 )  

Red soil from Chenzhou of Hunan and brown soil from Gongyi of Henan were collected and treated with Cu(NO₃)₂, Zn(NO₃)₂ or Cd(NO₃)₂, respectively for 2 weeks,and Rhizobium fredii strain HN01 was inoculated.Sequential extraction method was employed to investigate the forms of Cu, Zn and Cd in the examined soils with the absence and presence of rhizobia. The results showed that after inoculation,the total amount of solid bound Zn decreased 10%,and the amount of Zn associated with carbonate, Mn oxides,and organic matter fraction decreased 9～26%. No significant change was observed for the total amount of Zn combined with the solid phase of red soil in the presence of rhizobia. However, the amount of specifically adsorbed and Mn oxides bound Zn decreased, while the amount of exchangeable Zn increased. Inoculation of rhizobia depressed the release of Cu to the soil solution,and increased the total amount of Cu associated with the solid phase of brown soil. The increase of the amount of exchangeable Cu and of the Cu in fractions of carbonate, Mn oxides and organic matter ranged from 20% to 54%. There was no significant change for the level of Cd in the solution in both soils after rhizobia inoculation. The amount of exchangeable and organic Cd increased 22% and 11%, while the specifically adsorbed,and Mn oxides bound Mn decreased 14% and 29%, respectively. The different influence of rhizobia on the morphological distribution of test heavy metals in two soils was mainly ascribed to the soil pHchanges.

Root colonization and nodulation of Sinorhizobium fredii HN01DL in Glycine max rhizosphere

LI Youguo, ZHOU Junchu

2003, (8):  1283-1286. 

Asbtract ( 0 )  

Rhizobox soil microcosms studies on the colonization, dispersal and nodulation of Sinorhizobium fredii HN01DL marked with luxAB gene in Glycine max rhizosphere showed that the colonization dynamics and the density of HN01DL in non-sterilized rhizobox-soil microcosms were different from those in sterilized rhizobox soil microcosms. The colonization density of the former reached the maximum (8.65 log cfu·g^-1 root)12 days after the coated seeds planted,and that of the latter decreased rapidly at the early stage and achieved the maximum (6.88 log cfu·g^-1 root)15 days afterwards. Furthermore, the colonization density of HN01DL reached the maximum (7.05 log cfu·g^-1 root) in section A (0～4 cm) of root system 5 days after seeds planted,decreased slowly and kept a relative stable level until 19 days, and began to rise up again33 days afterwards.The strain could also disperse to the place of 16 cm from seed to root tip by 46 days after seed planted. HN01DL maintained a constantly higher colonization density level in section A of root system, formed the largest number of luminescent nodules (total 16.3, dominantly located in main root of section A),and had the highest luminescent percentage (68.8 %). The luminescent nodule percentage decreased gradually along section Ato Eof root system,and no luminescent nodule was detected in section Eof root system.

Effects of sunlight and temperature on ultrastructure and functions of chloroplast of cucumber in solar greenhouse

ZHANG Zhenxian, GUO Yankui, AI Xizhen, ZHANG Fuman, HE Qiwei, SUN Xiaolei, JIAO Zhigao

2003, (8):  1287-1290. 

Asbtract ( 0 )  

Studies on the effects of sunlight and temperature on the ultrastructure and functions of leaf chloroplasts of cucumber (Cucumis sativus L.) in solar greenhouse showed that the size of cells, chloroplasts, and starch grains and the number of chloroplast, grana, grana lamella and grana thickness of leaf chloroplast of cucumber increased with lowering leaf position. The microstructure of leaves and the ultrastructure of chloroplast of cucumber leaves were different because of the difference of temperature and sunlight among different months. In January, the light intensity was lower,and the cell size of cucumber leaves was larger than that in May, but the number of chloroplasts was less than that in May. The relationships between photosynthetic rate (Pn) and ultrastructure of chloroplast of cucumber leaves were not direct and very close. The Pn of the fourth leaf of cucumber was the highest, that of the first spreading out leaf was the second, and the near ground leaves had the lowest Pn.The primary reasons of the difference of Pn among different position leaves were that the leaf age and accepted light intensity were different. If different position leaves of cucumber accepted the same sunlight intensity, the difference of Pn among leaves of different positions would be smaller. Less efficient light hours and lower light intensity were the main factors influencing cucumber growth and yield in solar greenhouse. Comparatively, under sunny circumstance,the restriction of temperature on cucumber growth was very small, but in cloudy days, lower temperature induced by low light intensity became a key factor that restricted cucumber growth.

Validation of the ALMANAC model with different spatial scale

XIE Yun, James Kiniry, LIU Baoyuan

2003, (8):  1291-1295. 

Asbtract ( 0 )  

The ALMANACmodel was validated in a drought stressed year and in a period from 1989 to 1998 at different sites of Texas to evaluate its ability in simulating maize and sorghum yields at different spatial scales and to extend its application range. There were 11 sites for maize and 8 sites for sorghum in plot size simulations, and 9 counties for maize and sorghum in county level simulations. The model showed similar accuracy in simulating both plot size and county level mean grain yields. It could also simulate single year yields under water limited climatic conditions for several sites and mean county yields of maize and sorghum, and had small CVvalues of mean yields for a long term prediction. The mean error was 8.9% for sorghum and 9.4% for maize in field scale simulations, and was only 2.6% for maize and 0.6% for sorghum in county level mean yield simulations.Crop models often require extensive input data sets to realistically simulate crop growth. The development of such input data sets is difficult for some model users. The soil, weather, and crop parameter data sets developed in this study could be used as the guidelines for model applications in similar climatic regions and on similar soils.

Effects of growing process and climatic conditions on grain quality of spring-sown wheat

WU Dongbing, CAO Guangcai, QIANG Xiaolin, LI Meng, WANG Xiufang, CHEN Heqin

2003, (8):  1296-1300. 

Asbtract ( 0 )  

In the period of 1998～2000, 10 wheat varieties were used to study the effects of growth, development process and climatic conditions on the quality of wheat grains through spring sowing experiments in Beijing. The results showed that there were no significant variations on the quality traits among the varieties while there were significant variations among different years. The most significant negative correlation had been shown between the days from sowing to ripening and hardness of the grains and between the days from heading to ripening and the content of wet gluten of the grains. There was a significant negative correlation between day night temperature difference during the period from heading to ripening and content of NIR protein. The results also showed that there was most significant negative correlation between total radiation, day night temperature difference and the content of wet gluten of the grains. There was significant positive correlation between total sunlight and the content of wet gluten of the grains. The significant negative correlation was present between sedimentation value and total radiation, total sunlight, average temperature of daytime, day night temperature difference.

Temporal and spatial distribution characteristics of the crop root in intercropping system

ZHANG Enhe, HUANG Gaobao

2003, (8):  1301-1304. 

Asbtract ( 0 )  

The ecological mechanism of competition and compensation between the crop root systems of two different intercropping patterns, wheat-soybean and corn-cabbage, was studied by field experiment. The results showed that the annual growth peak of wheat soybean roots in intercropping was interlacing, the growth of root weight and length expressed synchronism, and the peak of root weight was appeared earlier than that of root length. The vertical distribution of the two crops' root system in two intercroppings was reduced gradually along with soil depths, which also showed that the multiple growth waves moved progressively. The root system distributed horizontally in intercropping system also showed a clearly unbalanced distribution. The root system distribution of out row for corn elongated 20.4～40.8 cm to cabbage rows, but that of cabbage elongated only 8.5～12.6 cm to corn. The cross extent of root systems in corn cabbage intercropping was decreased from 40.2 cm to 20.1 cm by fertilization, and the place of cross point for root concentrated region was changed from 20.5 cm to 12.4 cm below soil surface by fertilizer supply. The place of cross point for root concentrated region was an important index to decide the degrees of competition.

Multiplication technique of rice T(P)GMS line with double low critical temperature values using cold water irrigation

XU Mengliang, LIANG Manzhong, LIU Guiquan, CHEN Liangbi, ZHOU Guangqia, ZHOU Guanxiang, QIU Xiulan, HUANG Shiqi

2003, (8):  1305-1308. 

Asbtract ( 0 )  

In this paper, cold water irrigation multiplication technique was used to solve the difficulty of multiplying rice TGM Sline 96-5-2S(Oryza sative L.) with double low critical temperature values under natural air temperature condition. The results indicated that irrigating rice TGMS line 96-5-2S with different temperature underground cold water from the stage of pistil and stamen primordia differentiation to the stage of pollen filling for 15 days, and keeping the water depth 18～22 cm, the seed set rate of 96-5-2S decreased with increasing irrigating water temperature. When the average temperature of irrigation water was 18.5～19.8 ℃, the seed set rate ranged from 40.5% to 57.6%, and the yield ranged from 3.30 t·hm^-2 to 4.35 t·hm^-2.While the temperature was 20.5～21.3 ℃, the seed set rate and yield sharply decreased to 2.5～10.4% and 0.21～0.90 t·hm^-2, respectively. When the average temperature was 22.3～23.5 ℃, both the seed set rate and yield were zero. Under the same irrigation water temperature (average 19.8 ℃) and the same irrigating period (phase Ⅳ to phase Ⅶ), the seed set rate and yield of 96-5-2S with deep water irrigation (18～22 cm) was very significantly higher than those of 96-5-2S with shallow water irrigation (7～10 cm). Under the conditions of same irrigation water temperature (average19.8 ℃) and same water depth (18～22 cm) but different irrigating periods (15 days from phase Ⅳ to phaseⅦ, 20 days from phase Ⅲ to phase Ⅶ, and 25 days from phaseⅡ to phaseⅦ), the difference of seed set rate and yield of 96-5-2S between15 day treatment and 20～25 day treatment was not significantly different. It is confident that 96-5-2S could multiply with underground cold water irrigation. The main technique index was that irrigating water temperature should be 18～20 ℃,irrigating period should be from phase Ⅳ to phase Ⅶ, and irrigating water depth should be 18～22 cm.

Photooxidation characteristics of super-hybrid rice "Liangyoupeijiu" and its parents

WANG Rongfu, ZHANG Yunhua, QIAN Lisheng, YU Jianglong

2003, (8):  1309-1312. 

Asbtract ( 0 )  

With comparison of the differences of light absorption and active oxygen metabolism between super-hybrid rice "Liangyoupeijiu" and its parents, this paper provided a physiological foundation of matching and grouping for cultivating anti photooxidized hybrid rice. TPS-photosynthetic system and FMS2-fluorescence (Hansatech, UK) were used to respectively determine the photosynthetic rate and the chlorophyll fluorescence in the rice leaves that had been processed in artificial photooxidization. Meanwhile, the contents of chlorophyll, protein and malonaldehydic acid (MDA) as well as the activation of superoxide dismutase (SOD) and peroxidase (POD) were determined. The results showed that the photosynthetic rate of "Liangyoupeijiu" was 2.4% lower than that of its female parent, and 23% higher than that of its male parent. After eight days anti photooxidization process, its chlorophyll content was higher than that of its female parent by 33%, protein by 15%, initial photochemical efficiency by 30%, SOD by 32% and POD by 100%, while its photochemical quince coefficient was lower than that of its female parent by 9% and MDA by 50%. It showed that there was not much difference between the filial generation and its male parent. The super hybrid rice "Liangyoupeijiu" was very efficient for solar energy utilization under the condition of photooxidization, and had outgrown its parents in the aspect of anti photooxidization.

Effect of iron oxide addition on hydrogen, carbon dioxide and methane geneses in paddy soil

QU Dong, ZHANG Yiping, S. Schnell, R. Conrad

2003, (8):  1313-1316. 

Asbtract ( 0 )  

Paddy soil is an important contributor for atmospheric methane. The methanogenesis is related to the production of acetate, hydrogen and carbon dioxide during the decomposition of organic matter under anaerobic conditions. As electron acceptors, iron (Ⅲ) oxides can effectively compete with electrons in the transformation of organic matter into methane. Its mechanism maybe relates to the consumption of H₂ and CO₂. After added ferrihydrite and lepidocrocite, the H₂, CO₂ and CH₄ were determined during the anaerobic incubation of slurries at 25 ℃ for 105 days. The results indicated that the addition of ferrihydrite and lepidocrocite could greatly decrease the concentration of H₂, CO₂ and CH₄, and ferrihydrite had a stronger effect than lepidocrocite. In this system, the balance of organic-C was disturbed, CH₄-C and CO₂ Cwere reduced, but the CO₃^2--C fixed by slurry was greatly increased.

Integrated evaluation of eco-agricultural practices in Deqing County, Zhejiang Province

CHEN Jie, HU Bingmin

2003, (8):  1317-1321. 

Asbtract ( 0 )  

Integrated index method was used to evaluate the practices of eco agriculture in Deqing County in 1990～1998. The results showed that the integrated benefit, resources use, and ecological, economic and social benefits appeared a rising trend.The value of integrated benefit index in 1998 was 2.36 times of that in 1990.The benefit index, however, also fluctuated in these years, which meant that the eco agricultural system of Deqing County still had some problems to be resolved.Adjusting industry structure in rural areas, lessening pollution produced by rural industry,and improving stability of eco agricultural system should be highlighted in the next stage.

Effect of enhanced UV-B radiation on competition among several plant species

YUE Ming, WANG Xunling

2003, (8):  1322-1326. 

Asbtract ( 0 )  

The effect of enhanced UV-B radiation (280～315 nm, approximating a 15% ozone layer reduction) on competitive interaction between spring wheat (Triticum aestivum) and wild oat (Avena fatua) was examined in the field. The density dependent mortality of both wheat and wild oat did not exhibit a significant difference between control and UV-B treatments. Arelatively high degree of competitive stress enhanced the effect of UV-B stress on biomass reduction.Under UV-B enhancement,the relative competitive status of wheat in terms of total biomass and aboveground biomass increased,but decreased when based upon grain production. Shifts in competitive balance occurred with significant changes in total biomass, especially when plants grew at higher densities in monocultures and mixtures. There were different effects in direction and intensity of UV-Bradiation on competition balance of the other three species pairs, but in general, the effect of UV-Bwas in favor of monocotyledonous. The results implied that total degree of competitive stress,especially interspecific competition,might be crucial to assess the effect of UV-B enhancement on agriculture ecosystem properly.

Effects of grazing, cutting and decapitating on grass populations on the artificial grassland in subtropical zone of China

BAO Guozhang, LU Guanghua, GUO Jixun, BAO Jianyin

2003, (8):  1327-1331. 

Asbtract ( 0 )  

Studies on the effects of grazing, cutting and decapitating on grass populations on the artificial grassland in the subtropical zone of China showed that moderate grazing and cutting could increase the adaptability of Dactylis glomerata and Lolium prenn due to decapitating. Decapitating could rescind the apical dominance and reproduction growth of grass, and hence,the ecological effects of grazing and cutting on grass could be realized by decapitating, and the population density, caloric value and energy accumulation of Dactylis glomerata and Lolium prenn increased obviously. Apical dominance of grasses could lower the population density, energy accumulation and intra population competitive ability.

Clonal growth of stoloniferous herb Potentilla anserina on degraded and non-degraded alpine meadow soil

SHEN Zhenxi, CHEN Zuozhong, WANG Yanhui, ZHANG Jingli, ZHOU Huakun

2003, (8):  1332-1336. 

Asbtract ( 0 )  

The clonal growth of Potentilla anserina on degraded and non degraded Kobresia humilis meadow soil was studied by a transplanting experiment in the field. No significant differences in numbers of stolons, height, and leave size per mother ramet were observed between the two soils, but the numbers of leaves per mother ramet, length and width of stolon,and spacer length were significantly different. There were more leaves per mother ramet, longer stolon and spacer, and wider stolon on degraded soil, where available nutrient was poor than in non degraded soil. Under degraded alpine meadow soil condition, the clonal plant species might produce much more photosynthetic product to support stolon growth by the increase of leave numbers per mother ramet,and the longer and wider stolon could intensify the foraging ability of the mother ramet that would benefit to daughter ramet. Both mother and daughter ramet of Potentilla anserina invested much more biomass to their underground part (root system) in non degraded soil to increase the survival rate of daughter ramet.

Optimizing of pastures grazing pattern with biomass growth and consumption models

YE Xujun, CHEN Jie, WANG Zhaoqian

2003, (8):  1337-1342. 

Asbtract ( 0 )  

This paper discussed the biomass growth and consumption processes in grazed pasture ecosystems from a theoretical point of view, simulated the dynamics of these two processes with mathematical models, and analyzed the mechanism of ecological balance in pasture ecosystems from the perspective of these two processes. With the proposed biomass growth and consumption models,the dynamics of cumulative biomass consumption during one production cycle was simulated, and the optimal grazing strategies of pastures were proposed. The results could be valuable for pasture grazing management in practice.

Factors restricting growth of heterotrophic bacteria in the water body of West Lake, Hangzhou

WU Genfu, YANG Zhijian, ZHOU Xueping, WU Jie

2003, (8):  1343-1346. 

Asbtract ( 0 )  

Restricting factors of bacteria growth were studied by pure culture and natural culture test. The results showed that organic carbon source available for bacteria was more important than (NH₄)₂SO₄ and KH₂PO₄, while higher pH, and rich biomass of phytoplanktons and zooplanktons in the water restrained the growth of heterotrophic bacteria. Under natural culture experiment, Azotobacter increased after 0.5% glucose was added, and a lot of mildew grew after adding0.5% glucose with 0.1%(NH₄)₂SO₄ and 0.1% KH₂PO₄, while Pseudomonas enriched 30～57% after adding0.01% beef extract. It was also showed that bacteria growth potentiality in natural water could reach to 10⁵cfu·ml^-1.

Multianalysis between chlorophyll-a and environmental factors in Qiandao Lake water

LU Huanchun, WANG Feier, CHEN Yingxu, YU Zuoming, FANG Zhifa, ZHOU Gendi

2003, (8):  1347-1350. 

Asbtract ( 0 )  

In this paper,the regression equation between chlorophyll-a (Chla) and some environmental factors was calculate by multiple stepwise regression,based on the monthly monitoring data in the Qiandao Lake from Jan.1999 to Dec.2000, and modified Carlson trophic state index for all the sampling sites was also analyzed.The results indicated that the spatial and temporal distribution of chlorophyll a in the sampling sites were varied strongly, the concentration of chlorophyll a in the Xin'an river changed from 50 mg穖^-3 to 30 mg穖^-3, but that in the lake was under 5 mg穖^-3. The modified Carlson trophic state index (TSI_M) for the sampling sites in southeast of the lake was under 37 (belonging to olligotrophic), and the others were under 53 (belonging to mesotrophic). In different sampling sites, the significant environmental affecting factors for chlorophyll a were different.However, the relationships between chlorophyll a and water temperature and total phosphorus were positive,and that between chlorophyll a and diaphaneity was negative.

Effects of rehabilitation of submerged macrophytes on nutrient level of a eutrophic lake

WU Zhenbin, QIU Dongru, HE Feng, FU Guiping, CHENG Shuiping, MA Jianmin

2003, (8):  1351-1353. 

Asbtract ( 0 )  

The effects of rehabilitation of submerged aquatic vegetation on nutrient level of eutrophic waters were investigated by using large scale enclosure system installed in a hyper-eutrophicated lake, Lake Donghu of Wuhan. The concentrations of total nitrogen (TN) and total phosphorus (TP) of the enclosures with artificially recovered submerged macrophytes were significantly lower than those of the macrophyte free control enclosure and the lake water, and the TPof macrophyte enclosure was found to be around 0.1 mg稬^-1 and relatively stable. The concentration of ammonia and nitrite of the macrophyte enclosures were lower than those of the control and the lake water. However, the nitrate concentrations did not differ among the various water bodies. It was demonstrated that re establishment of submerged macrophytes could efficiently reduce the nutrient level and thus control the overgrowth of the undesirable algae and improve water quality in the eutrophic lakes.

Sublethal effects of insecticides on fecundity of multicolored Asian ladybird Harmonia axyridis

WANG Xiaoyi, SHEN Zuorui, XU Wenbing, LU Jian

2003, (8):  1354-1358. 

Asbtract ( 0 )  

The effects of sublethal doses of 6 insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on the fecundity of multicolored Asian ladybird Harmonia axyridis were determined respectively. The results showed that in all treatments,the daily average number of eggs per female ladybird was about 40～55. Ladybirds pretreated with imidacloprid by contact and feeding methods, and with rotenone by feeding method produced significantly fewer eggs,compared with control. But the accumulative oviposition of ladybirds pretreated with 6 insecticides at sublethal level was no significant differences,compared with untreated ladybirds. The hatching rates of the eggs laid by ladybirds pretreated with 6 insecticides by two methods were all lower than that of control. The accumulative survivals from egg to pupal stage of all treatments decreased significantly. The developmental duration from egg to pupa of those treated with imidacloprid by two methods and with fenvalerate by contact method prolonged significantly, while that of those treated with rotenone by two methods and with fenvalerate, abamectin, pirimicarb, and azadirachtin by feeding method shortened obviously, but that of those treated with rotenone and abamectin by contact method had no differences with control. After the eggs were immersed with sublethal concentrations of imidacloprid, rotenone, fenvalerate and abamectin, the successful hatching rates were all lower than that of control, and the development periods prolonged clearly. The 1st instar larval survival rates of those treated with fenvalerate decreased significantly,and the survivals from 2nd instar larval to pupal stage also reduced to some extent. The total developmental duration of those treated with rotenone and fenvalerate prolonged significantly. These findings suggested that the effects of insecticides at low doses on the fecundity of ladybird were very complicated. The class, action mode,toxicity and exposure route of insecticides could affect the results of experiments.

Chaotic diagnosis of Nilaparvata lugens occurrence system

XU Xiaofeng, MA Fei, ZOU Yunding, CHENG Xianian

2003, (8):  1359-1362. 

Asbtract ( 0 )  

It is estimated that there are nearly 20 million hectares of rice crop being infested by Nilaparvata lugens, with an annual loss of some half a million tones of grain. In order to study the properties and laws of Nilaparvata lugens occurrence system further, the time series data of Nilaparvata lugens occurrence from 1986 to 1998 collected in Taihu Lake District were analyzed by using the methods of autocorrelation function, power spectrum figure, phase trajectory figure, poincare section, and return map of chaos theory. The results indicated that Nilaparvata lugens occurrence system in Yangtze River valley area in China had an obvious chaotic property, even though there was some interference of random noises.

Landscape pattern of Nanjing urban-rural ecotone

CHEN Caihong, HU Feng, ZHANG Luochen

2003, (8):  1363-1368. 

Asbtract ( 0 )  

Landscape ecological characteristics of the urban-rural ecotone of Nanjing City were studied by using remote sensing and geographical information system (GIS) techniques. Two representative study regions with the same area were chosen in the eastern and southern part of the city. The urban-rural fringe of both east (URFE) and south region (URFS) can be divided into three zones: fringe-paraurban zone, transition zone and pararural zone. URFE was basically characterized by low landscape diversity, dominance and fragmentation. The forest patches in URFE had larger area and average perimeter, while their average fractal dimension, average stretched index and separated degree were lower. The average area of vegetable land and paddy land was larger than that of south region. URFS showed higher landscape diversity, dominance and fragmentation, more and higher density of patches. The area and the perimeter of water and architectural patches in URFSwere also larger than that of URFE. The relationship between patch area and fractal dimension, stretched index and fractal dimension, patch number and area were discussed. The function and contributing factors of each type of patches, especially forestland, and the landscape characteristics and the ecological significance of corridors including road, river, and city wall of urban rural fringe were also analyzed.

Effect of transgenic plants on biodiversity of agroecosystem

NIE Chengrong, WANG Jianwu, LUO Shiming

2003, (8):  1369-1373. 

Asbtract ( 0 )  

The effect of transgenic plants on the biodiversity of agroecosystem is an important environmental issue. There are many researches in this field at home and abroad recently. This paper reviewed the advances of the researches based on three levels of biodiversity as genetic diversity, species diversity and ecosystem diversity. They included following aspects: the effect of insect-resistant transgenic crops on target pest; the effect of herbicide resistant transgenic crops on crops and wild weedy relatives; the effect of virus resistant transgenic crops on virus; and the effect of transgenic crops on non-target organisms. This paper also discussed the effect of transgenic crops on soil ecosystem and crop genetic diversity. Their potential risks included uncontrolled flows of genes to wild relatives; development of herbicide, insect, and virus resistance in wild relatives; reduced crop genetic diversity; and adverse effects on organisms that were not pests, such as beneficial insects.

Origin of SARS from accelerated evolution of a virus by combined pollution

ZHOU Qixing, WEI Shuhe, ZHANG Qianru, ZHONG Ming

2003, (8):  1374-1378. 

Asbtract ( 0 )  

The SARS virus origin which obviously differs from the theory of out-space origin and the theory of wildlife origin was theoretically discussed based on principles of pollution evolution ecology,pathogenesis and infectant characteristics of SARS,and some relevant experimental evidence. It emphasizes on the fact that increasingly combined pollution in China provides a substantial basis for virus evolution. Gene recombination and fusion of more than one virus in ecosystems should take charge with the origin of a SARS virus. In particular,a common cold or influenza virus can acceleratedly changed into a superpower common cold or influenza virus through genetic mutation and gene recombination by increasingly combined pollution. This work can be useful for human beings to overcome SARS in theory.

Effect of plants on methane production, oxidation and emission

DING Weixin, CAI Zucong

2003, (8):  1379-1384. 

Asbtract ( 0 )  

The paper reviewed the role of plants in the processes of methane production, oxidation and emission in soils. It was the abilities of different plants to excrete the quantity and quality of root exudates that resulted in discrepancies of methane production among plants and in plant growing seasons. The oxygen magnitude of the downward transport through the plant aerenechyma, which, in turn, also acted as a conduit for methane from the soil to the atmosphere, affected endogenous methane oxidation capacity with plants and with plant growing seasons. Plant through changing amount and density of plant aerenchyma altered its ability to transport methane from soil to atmosphere. In addition to soil properties, flux and pattern of methane emission from soils largely depended on plant abilities to excrete exudates and oxygen, and transport methane in different plant growing seasons.

Effects of land use change on carbon storage in terrestrial ecosystem

YANG Jingcheng, HAN Xingguo, HUANG Jianhui, PAN Qingmin

2003, (8):  1385-1390. 

Asbtract ( 0 )  

Terrestrial ecosystem is an important carbon pool, which plays a crucial role in carbon biogeochemical cycle. Human activities such as fossil fuel combustion and land use change have resulted in carbon fluxes from terrestrial ecosystem to the atmosphere, which increased the atmospheric CO₂ concentration, and reinforced the greenhouse effect. Land use change affects the structure and function of the terrestrial ecosystem, which causes its change of carbon storage. To a great extent, the change of carbon storage lies in the type of ecosystem and the change of land use patterns. The conversion of forest to agricultural land and pasture causes a large reduction of carbon storage in vegetation and soil, and the decrease of soil carbon concentration is mainly caused by the reduction of detritus, the acceleration of soil organic matter decomposition, and the destroy of physical protection to organic matter due to agricultural practices. The loss of soil organic matter appears at the early stage after deforestation, and the loss rate is influenced by many factors and soil physical, chemical and biological processes. The conversion of agricultural land and pasture to forest and many conservative agricultural practices can sequester atmospheric carbon in vegetation and soil. Vegetation can sequester large amounts of carbon from atmosphere, while carbon accumulation in soil varies greatly because of farming history and soil spatial heterogeneity.Conservative agricultural practices such as no tillage, reasonable cropping system,and fertilization can influence soil physical and chemical characters, plant growth, quality and quantity of stubble,and soil microbial biomass and its activity,and hence, maintain and increase soil carbon concentration.

Ecological adaptability and application safety of Epiblema strenuana as a biocontrol agent against ragweed

MA Jun, WAN Fanghao, GUO Jianying, YOU Lanshao, YANG Hanmin

2003, (8):  1391-1394. 

Asbtract ( 0 )  

Epiblema strenuana is the most important natural enemy against Ambrosia artemisiifolia, A. trifida and Parthenium hysterophorus.In this paper,its ecological adaptability and application risk as a biological agent against ragweed was analyzed and reviewed. Epiblema strenuana had a restrict host specificity, with all the field hosts belonging to Ambrosiinae, and its selective risk on sunflower and chrysanthemum was less than0.01 or/and zero (no risk). 15～35 ℃ was the suitable temperature regimes for E. strenuana to develop, and lower constraint temperature could reach -8～-12 ℃. The population size of this insect could increase 23 and 4 times on A. artemisiifolia, A. trifida and Xanthium sibiricum after each generation, respectively. In the field, the infected plants had an average of 20～30 galls per plant, and died with 5.2 and 26 galls before and after rosette stage.The spread distance of this moth within12 months after release was more than100 km. It indicated that E.strenuana was an effective and safe agent for cereal and economic crops, ornamental plants, and indigenous natural enemy in the introduced region.

Construction and important factors analysis of natural life table of diamonthback moth, Plutella xylostella under pesticides treatment

LIU Xin, YOU Minsheng

2003, (8):  1395-1397. 

Asbtract ( 0 )  

The natural life tables of diamonthback moth (DBM), Plutella xylostella under pesticides treatment were constructed,and the construction method of item "pesticide" was particularly discussed.The life tables indicated that the indices of population trend (I) under the treatment with 80% Dichlorvos EC 1000x and the contrast were 0.7796 and 1.4804, respectively,showing that Dichlorvos had some control on DBM. But,Dichlorvos had some effects on natural enemies of DBM. The decrease of parasitism rate at pupa stage was most obvious,which indicated that Dichlorvos had some effects of killing and wounding on the natural enemies of DBM.

Optimization of spatial arrangements and patterns for shelterbelts or windbreaks

ZHU Jiaojun, JIANG Fengqi, FAN Zhiping, ZHOU Xinhua

2003, (8):  1205-1212. 

Asbtract ( 1122 )   PDF (998KB) ( 456 )  

Spatial arrangements and patterns of shelterbelts or windbreaks are the key factors influencing the shelterbelt structures, shelter benefits, and shelterbelt sustainability. In order to keep the shelter benefits and achieve the sustainability of shelterbelts, it is necessary to keep the reasonable arrangements and patterns in spatiality and the continuation in time. Based on the investigations on the shelterbelts, which were established in1992 as the models in Shuangjingzi Township, Changtu County, Liaoning Province, and combined with the experiences and practices of shelterbelt management, the authors studied and summarized the arrangements and patterns of shelterbelts, which included the direction of a single shelterbelt and shelterbelt networks, the arrangement of tree composition in a shelterbelt, and the mixture of tree species for shelterbelts. Additionally, the spacing intervals between shelterbelt and the spatial patterns for regional shelterbelts were also discussed. The results indicated that the direction of both single shelterbelt and shelterbelt networks should be perpendicular to the disaster winds. It is better for the structure of a shelterbelt to arrange the trees in triangle form in a shelterbelt. According to the edge effect, the tree species which grow slowly should be arranged in the edge lines, but the tree species which grow fast should be arranged in the inner lines of the mixed shelterbelts. Optimal spacing intervals between windbreaks could be predicted from the indices of a given windbreak structure (porosity), percentage of desired wind speed reduction, and tree growth model (model for determining initial protective maturity age). The patterns of shelterbelts in large scale should be evaluated and arranged according to the principles of landscape ecology. The results mentioned above would provide the evidences for shelterbelt sustainable management.

Relationship between photo-inhibition of photosynthesis and reactive oxygen species in leaves of poplars suffering root osmotic stress

FENG Yulong, ZHANG Yajie, ZHU Chunquan

2003, (8):  1213-1217. 

Asbtract ( 980 )   PDF (859KB) ( 429 )  

To know more about the photo inhibition of photosynthesis under field conditions, its relationship with reactive oxygen species (ROS) in leaves of poplar clone seedlings was studied under osmotic stress conditions. With the increasing duration of osmotic stress and the enhancement of stress intensity, the ROSlevel, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity increased, while the activities of catalase (CAT) and ascorbate peroxidase (APX) decreased, resulted in the unbalanced ROSmetabolism and intensified photo inhibition. The inhibition of SODactivity by copper diethyldithiocarbamate or the accelerated generation of O₂^ˉ. with methyl viologen (MV) could also induce the photo inhibition. The decrease of the ability of poplar clone seedlings in scavenging H₂O₂ under osmotic conditions limited the dissipation of excess light energy and the role of photosynthetic apparatus in protecting against photo inhibition through Mehler reaction. Photo inhibition might be related to the accumulation of ROS.

Effects of ultraviolet-C irradiation on membrane lipid peroxidation and activity of PSⅡ electron transport in chloroplasts of Taxus cuspidata needles

DU Yingjun, JIANG Ping, WANG Bing, SHI Yi

2003, (8):  1218-1222. 

Asbtract ( 1098 )   PDF (624KB) ( 352 )  

The isolated chloroplasts of Taxus cuspidata needles treated with 12 W·m^-2 of ultraviolet C (UV-C, 254 nm) irradiation were studied under laboratory conditions. The results showed that with the increase of UV-C irradiation, the carotenoids (Car) and glutathione (GSH) contents and superoxide dismutase (SOD) activity were decreased, while the malondialdehyde content (MDA) and the relative permeability of chloroplasts membrane were increased to various extents. The PSⅡ electron transport activity was conspicuous decreased, which had a significant inverse ratio with photosynthetically active radiation(PAR). UV-C irradiation was insensitive on chlorophyll. The results indicated that membrane lipid peroxidation of chloroplasts caused by UV-C radiation was the reason of the decrease of PSⅡelectron transport activity.

A preliminary study on the chemical properties of precipitation, throughfall, stemflow and surface run-off in major forest types at Dinghushan under acid deposition

LIU Juxiu, ZHANG Deqiang, ZHOU Guoyi, WEN Dazhi, ZHANG Qianmei

2003, (8):  1223-1228. 

Asbtract ( 1038 )   PDF (594KB) ( 449 )  

Studies on the chemical properties of precipitation, throughfall, stemflow and surface run off in major forest types at Dinghushan under acid deposition showed that the pHvalue of precipitation was about 4.90,and the frequency of acid rain was over 62%. In broad leaved forest, the pHvalue of precipitation was lower than that of throughfall, but higher than that of stemflow and especially the surface run off, indicating that the soil was naturally acidified. In mixed forest, both throughfall and surface run off had a higher pHvalue,but stemflow had a lower pHvalue than precipitation. The throughfall and stemflow were more acidified than precipitation in coniferous pine forest, but the surface run off had a higher pHvalue than precipitation. These results suggested that among the three major forest types at Dinghushan,the canopy of broad leaved forest had the highest buffering ability,whereas for the soil,the coniferous forest had the highest soil buffering capacity. The concentrations of nutrient elements, such as P, K, Ca, Na and Mg in the throughfall, stemflow and surface run off were higher than those in bulk precipitation in all forests at Dinghushan, some even 10 times higher, indicating that a large amount of nutrients were leached from the canopy. The concentrations of nutrient elements in stemflow were higher than those in throughfall in all forests, and the concentration of nutrient elements in surface water was higher than those in atmospheric rainfall. Coniferous forest had a higher concentration of nutrients in the throughfall and stemflow and a lower nutrient concentration in the surface run off than other forest types,which implied that nutrient loss was more serious in broad leaved and mixed forests than in coniferous forests.

Method for measurement of optical stratification porosity (OSP) and its application in studies of management for secondary forests

ZHU Jiaojun

2003, (8):  1229-1233. 

Asbtract ( 1103 )   PDF (654KB) ( 340 )  

Secondary forest is the main body of forests in China, and hence, its management plays a very important role in the projects of natural forest conservation and ecological environment construction in this country. The structure, especially the vertical stratification structure of secondary forest is one of the key factors in the management of secondary forest, and can be considered as the base of its management. Based on previous studies, the concept of stratification porosity was introduced, and the optical stratification porosity (OSP), which is the two dimensional alternative measurement of stratification porosity, could be used to represent the vertical stratification structure of secondary forest. The method using hemispherical photographic silhouette (photographic silhouette taken with fisheye lens) to estimate the OSPof a forest stand was also introduced. In addition, the possible applications of OSPin studies on the structure and restoration ecology of secondary forest, and the theory and techniques for the management of secondary forest were also given in this paper.

Effects of soil temperature and moisture on soil respiration in different forest types in Changbai Mountain.

WANG Miao, JI Lanzhu, LI Qiurong, LIU Yanqiu

2003, (8):  1234-1238. 

Asbtract ( 1786 )   PDF (176KB) ( 647 )  

The effects of soil temperature (0, 5, 15, 25, 35 ℃) and water content on soil respiration in three forest types in Changbai Mountain were evaluated in laboratory condition. The results indicated that the soil respiration rate was positively correlated to soil temperature from 0 to 35 ℃ and it increased with soil water content from 0.21 to 0.37 kg·kg^-1. The soil respiration rate decreased with soil water content when water content was over the range. The result suggested the interactive effects of temperature and water content on soil respiration. There were significant differences in soil respiration among the various forest types and the highest was in broad leaf Korean pine forest, then in erman's birch forest, and it was the lowest in dark coniferous forest. The optimal condition for soil respiration in broad leaved Korean pine forest was at 35 ℃ under 0.37 kg·kg^-1 water content, and it was at 25 ℃ under 0.21 kg·kg^-1 in dark coniferous forest and at 35 ℃ under 0.37 kg·kg^-1 water content in erman's birch forest. Because the forests of broad leaf Korean pine, dark coniferous and erman's birch are located at various altitudes, the soil temperatures had 4～5 ℃ variation in different forest types during the same period. The soil respiration rates measured in brown pine mountain soil were lower than those in dark brown forest and they were higher in mountain grass forest soil than those in brown pine mountain soil.

Quantitative simulation on the vertical distribution of soil organic matters in mountainous soil profiles in the subtropical area, south China

CHEN Qingqiang, SHEN Chengde, SUN Yanmin, YI Weixi, JIANG Mantao, PENG Shaolin, LI Zhi'an

2003, (8):  1239-1245. 

Asbtract ( 1141 )   PDF (849KB) ( 342 )  

Quantitative descriptions of soil organic matter (SOM) dynamics, i.e., their distribution, turnover and movement, are essential for the running of the simulation of terrestrial ecosystem organic matter models. In this study, based on utilizing SOM diffusion translation decomposition model,two soil profiles were selected in different vegetation zones at Dinghushan Mountain for quantitative studies on SOMdynamics and their controlling factors. SOM were divided into three kinds of compartments: rapid compartment with turnover rate of 0.1～1·yr^-1, slow compartment with turnover rate of 0.002～0.02·yr^-1, and stable compartment with turnover rate of 0.0001～0.001·yr^-1. The numerical results suggested that SOM distribution in soil profile in subtropical mountainous areas of south China obeyed the law of diffusion motion, translation motion and decomposition. The turnover rate of SOM rapid compartment was 0.483·yr^-1 in the forest vegetation zone, and was 0.694·yr^-1 in the shrub vegetation zone. The turnover rates of SOM slow compartment in the two kinds of vegetation zones were both 0.02·yr^-1, and the turnover rates of SOM stable compartment in the two kinds of vegetation zones were both 0.001·yr^-1. SOM diffusion rate and translation rate for the forest vegetation zone was 4 cm²·yr^-1 and 0.2 mm·yr^-1, respectively, and the two rates of the shrub vegetation zone were 1 cm²·yr^-1 and 0.5 mm·yr^-1, respectively. The obvious discrepancy between numerical values and measuring values for SOM content occurred in the 0～10 cm sections of the profiles, which might be due to the fact that the upper sections were at the interface between lithosphere and atmosphere, and were influenced directly by changes of climatic and environmental factors. The two kinds of values for SOM content were identical below the upper section of the profiles, and it indicated stable pedogenesis environments. Diffusion motion had obvious influences on SOM vertical distribution, and translation motion had clear impacts on SOM distribution only in the upper 0～10 cm section. Comparison analysis suggested that SOM dynamics were controlled mainly by soil profile qualities such as SOM content, clay content, soil fabric, void types and their developments, soil fauna and microorganism activities, etc. With the increasing of primary production of aboveground vegetation, the turnover rate of SOM rapid compartment decreased and SOM content increased, which provided scientific basis for increasing soil carbon sink through anthropogenic effects.

Ecological distribution of soil microorganism in artificial greenbelt in hinterland of Takilimakan Desert and their relations with soil factors

ZHOU Zhibin, LI Peijun

2003, (8):  1246-1250. 

Asbtract ( 1262 )   PDF (1661KB) ( 505 )  

Studies on the distribution of soil microorganisms in the artificial greenbelt in hinterland of Takilimakan Desert and the effects of soil features on the distribution showed that under saline water irrigation, the activities of soil microorganisms increased sharply, and the soil structure and nutrient status were improved. Among soil microorganisms, bacteria were predominant, actinomyces were the next, and fungi were the least. There were more microorganisms in upper than in deeper soil layers. Soil microorganisms near shelter-forest had a higher activity, and their quantities over 3m from shelter-forest were almost equal to those in shifting sand. The quantities of soil microorganisms varied with seasons, and there were distinct differences among different sites of forests. Among the measured 11 soil factors, the interactions between pairs of soil available phosphorus available potassium, organic matter available potassium, available nitrogen available potassium, available nitrogen available phosphorus, organic matter-available phosphorus, available phosphorus available nitrogen, total nitrogen available potassium, available potassium available phosphorus, total nitrogen available phosphorus, and water contents available nitrogen were significant, with the correlation coefficients of 1.37～2.58. The direct effects of available phosphorus, available nitrogen, and total nitrogen on the microbial quantity were significant, with the coefficient of 1.01～2.58.

Dynamics of soil inorganic nitrogen in middle mountain moist evergreen broadleaf forest under different disturbance intensities in Ailao Mountain

LI Guicai, HAN Xingguo, HUANG Jianhui, WAMG Changyao

2003, (8):  1251-1256. 

Asbtract ( 1055 )   PDF (957KB) ( 337 )  

The effects of three different intensities of disturbance on soil NH₄⁺-N and NO₃^--N contents were studied in three community types (primary Lithocarpus xylocarpus forest, secondary oak forest,and tea plantation, which represent three different intensities of disturbance). The results showed that the contents of inorganic nitrogen in soil (0～15 cm) of three community types had marked differences.Soil organic matter and total nitrogen decreased, while C/Nratio increased,with the increasing intensity of the disturbance. Simultaneously, the potential lose of NO₃^--N increased. It suggested that the disturbance was not in favor of the retainment of soil fertility and the positive development of community succession. The soil organic matter, total nitrogen and C/N ratio were basically same at different spatial sites in same community, while the NO₃^--N contents were obvious difference. This implied that soil NO₃^--N content was less stable than NH₄⁺-N. In addition, NH₄⁺-N was the major component of the soil inorganic nitrogen, accounted for 95.5%～99.3% of the total content of soil inorganic nitrogen.

Properties of potassium loss from red soil slope land in different farming systems

YUAN Donghai, WANG Zhaoqian, CHEN Xin, GUO Xinbo, ZHANG Ruliang

2003, (8):  1257-1260. 

Asbtract ( 1032 )   PDF (442KB) ( 321 )  

The properties of potassium loss in red soil slope field under six cultivations were studied. The results showed that potassium lost mainly with bed load and runoff on surface of soil. The potassium lost mostly with runoff in slope field under contour, contour dam cultivated ways with less sediment except the fallow, under which the loss of potassium with bed load equaled to the loss of potassium with runoff. The potassium lost mostly with bed load in slope field under straight, grass strip and contour ditch cultivated ways with more sediment, and particulate potassium was the main form of potassium lost in runoff. Compared with straight cultivated way, other cultivated ways reduced soil potassium loss significantly. Contour, fallow, and contour dam cultivated ways were better than straight and grass stripe cultivated ways on controlling potassium loss. In the year of 2000, the potassium loss was mainly occurred during May to August accounting for 87.24～100% of total annual lost.

Effect of sulfur fertilization on yield production and sulfur content of crops and pasture in north China

CUI Yanshan, WANG Qingren

2003, (8):  1261-1264. 

Asbtract ( 965 )   PDF (214KB) ( 351 )  

Pot experiment on 3 crops (wheat, corn, oilseed rape) and a pasture (clover) under 5 levels (0, 5, 10, 20, 40 mg·kg^-1) of sulfur (S) was carried out to study Sapplication on yield production, Scontents and their relationship of these crops. The results showed that under Sapplication, the biomass of four plants increased by 5～32%, and the grain yield increased by 3～20%. The contents of Svaried with different corps, for example, the content of Sin the oilseed rape was the highest (0.479～1.228%), and that in corn was the lowest (only 0.043～0.091%). The contents of Sin different plant parts of the same crop had a positive correlation with content of Sapplication. Both the biomass and grain yield for all the crops except the clover had a close correlation with the content of Sapplication. With available Sin the soils increased, the amount of Sabsorbed by crops was increased at the beginning, and then decreased after reached the peak.

NO₃^--N leaching and distribution in soil profile in dry highland of Loess Plateau under long-term fertilization

DANG Tinghui, GUO Shengli, FAN Jun, HAO Mingde

2003, (8):  1265-1268. 

Asbtract ( 953 )   PDF (209KB) ( 353 )  

The NO₃^--N accumulation and distribution in soil profile of Loess Plateau dry highland were studied by long term field trials. The results showed that NO₃^--N was accumulated in the soil profile under N fertilization. Application of Pfertilizer or organic manure reduced the NO₃^--N content and its leaching depth in the soil profile. The deepest depth of NO₃^--N accumulation was 120～200 cm under N treatment, and the peak of the accumulation was the highest in NPMtreatment, with the depth of 60～120 cm. The NO₃^--N accumulation depth was 80～140 cm for NP. Without nitrogen application, there was no evident accumulation of NO₃^--N in soil profile. The more nitrogen used, the more NO₃^--N accumulated in soil profile. Under the same nitrogen application rate, NO₃^--N accumulation might decrease with increasing Papplication.

Decomposing effect of chemical-biological decomposing combined technique on rice straw and its fourier transform infrared spectroscopy

CAI Yanfei, LIAO Zongwen, WANG Dehan, LI Yurui

2003, (8):  1269-1272. 

Asbtract ( 988 )   PDF (423KB) ( 359 )  

The effects of several chemical biological combined decomposing techniques (CBCDT) on the decomposition of rice straw were studied by fourier transform infrared spectroscopy (FTIR). The results showed that under CBCDT treatments, rice straw could be better decomposed than in control. After seven days under CBCDT treatments, the straw turned into brown, and was easy to be broken down and obviously decomposed. FTIRspectra indicated that under chemical agent Abiological agent Acombined treatment, hydroxyl, ketonic carbonyl, methyl, methylene, methane and aliphatic compounds decreased, proteins and amino acids completely decomposed, but aromatic compounds (specially substituted group) increased, and hence, the humification of straw was accelerated.The effects of different decomposing agents on straw were decreased in the order of chemical degrade agent A>chemical degrade agent B, biological degrade agent A> biological degrade agent B> biological degrade agent C. The chemical agent Abiological agent Acombined treatment was the most effective among several treatments.

Effect of different cultivation practices on Fe and Cd content in iron plaque outside rice root and Cd content in rice root

SHI Kun, ZHANG Fusuo, LIU Xuejun, ZHANG Xudong

2003, (8):  1273-1277. 

Asbtract ( 1309 )   PDF (840KB) ( 358 )  

The effects of different cultivation practices-traditional flooding (TF), film mulching (FM), straw mulching (SM), and wetting cultivation (WC)-on Cd-concentrations in Indica and Japonica roots and on Cd and Fe concentrations in iron plaque outside the roots were studied at different growth stages (tillering, booting, filling and harvest) with a Cd polluted soil. The results showed that in all practices, the mean Fe concentration in iron plaque and the mean Cd concentration in roots of Japonica at tillering stage were 6.37 mg穖g^-1 and 25.49 mg穔g^-1, and greater than those of Indica, which were 4.52 mg穖g^-1 and 16.37 mg穔g^-1 respectively ; at booting stage, the mean Fe and Cd concentrations in iron plaque and the mean Cd concentrations of Japonica were 1.60,16.35 and 54.68 mg穔g^-1, and greater than those of Indica, which were 1.06 mg穖g^-1, 9.56 and 43.31 mg穔g^-1, respectively; at filling stage, the Fe concentrations in iron plaque of Japonica in SM and WC were 0.89 and 1.00 mg穖g^-1, and those of Indica were 0.63 and 0.30 mg穖g^-1 ; in all practices, the mean Cd concentrations in iron plaque and root of Japonica were 15.23 and 73.68 mg穔g^-1, and those of Indica were 3.46 and 52.38 mg穔g^-1 ; at harvest stage, the Fe concentration in iron plaque of Indica in TFwas 1.21 mg穖g^-1 and that of Japonica was 0.65 mg穖g^-1, but that of Japonica in SM was 0.94 mg穖g^-1 and that of Indica in SM was 0.55 mg穖g^-1 ; the Cd concentration in iron plaque of Japonica in WC was 7.96 mg穔g^-1,and that of Indica was 5.09 mg穔g^-1 ;the mean Cd concentration in root of Japonica was 54.53 mg穔g^-1 and that of Indica was 35.91 mg穔g^-1 in all practices.

Effects of rhizobia on morphological distribution of Cu, Zn and Cd in soil

CHEN Wenli, HUANG Qiaoyun, GUO Xuejun

2003, (8):  1278-1282. 

Asbtract ( 950 )   PDF (715KB) ( 411 )  

Red soil from Chenzhou of Hunan and brown soil from Gongyi of Henan were collected and treated with Cu(NO₃)₂, Zn(NO₃)₂ or Cd(NO₃)₂, respectively for 2 weeks,and Rhizobium fredii strain HN01 was inoculated.Sequential extraction method was employed to investigate the forms of Cu, Zn and Cd in the examined soils with the absence and presence of rhizobia. The results showed that after inoculation,the total amount of solid bound Zn decreased 10%,and the amount of Zn associated with carbonate, Mn oxides,and organic matter fraction decreased 9～26%. No significant change was observed for the total amount of Zn combined with the solid phase of red soil in the presence of rhizobia. However, the amount of specifically adsorbed and Mn oxides bound Zn decreased, while the amount of exchangeable Zn increased. Inoculation of rhizobia depressed the release of Cu to the soil solution,and increased the total amount of Cu associated with the solid phase of brown soil. The increase of the amount of exchangeable Cu and of the Cu in fractions of carbonate, Mn oxides and organic matter ranged from 20% to 54%. There was no significant change for the level of Cd in the solution in both soils after rhizobia inoculation. The amount of exchangeable and organic Cd increased 22% and 11%, while the specifically adsorbed,and Mn oxides bound Mn decreased 14% and 29%, respectively. The different influence of rhizobia on the morphological distribution of test heavy metals in two soils was mainly ascribed to the soil pHchanges.

Root colonization and nodulation of Sinorhizobium fredii HN01DL in Glycine max rhizosphere

LI Youguo, ZHOU Junchu

2003, (8):  1283-1286. 

Asbtract ( 993 )   PDF (229KB) ( 255 )  

Rhizobox soil microcosms studies on the colonization, dispersal and nodulation of Sinorhizobium fredii HN01DL marked with luxAB gene in Glycine max rhizosphere showed that the colonization dynamics and the density of HN01DL in non-sterilized rhizobox-soil microcosms were different from those in sterilized rhizobox soil microcosms. The colonization density of the former reached the maximum (8.65 log cfu·g^-1 root)12 days after the coated seeds planted,and that of the latter decreased rapidly at the early stage and achieved the maximum (6.88 log cfu·g^-1 root)15 days afterwards. Furthermore, the colonization density of HN01DL reached the maximum (7.05 log cfu·g^-1 root) in section A (0～4 cm) of root system 5 days after seeds planted,decreased slowly and kept a relative stable level until 19 days, and began to rise up again33 days afterwards.The strain could also disperse to the place of 16 cm from seed to root tip by 46 days after seed planted. HN01DL maintained a constantly higher colonization density level in section A of root system, formed the largest number of luminescent nodules (total 16.3, dominantly located in main root of section A),and had the highest luminescent percentage (68.8 %). The luminescent nodule percentage decreased gradually along section Ato Eof root system,and no luminescent nodule was detected in section Eof root system.

Effects of sunlight and temperature on ultrastructure and functions of chloroplast of cucumber in solar greenhouse

ZHANG Zhenxian, GUO Yankui, AI Xizhen, ZHANG Fuman, HE Qiwei, SUN Xiaolei, JIAO Zhigao

2003, (8):  1287-1290. 

Asbtract ( 1062 )   PDF (512KB) ( 382 )  

Studies on the effects of sunlight and temperature on the ultrastructure and functions of leaf chloroplasts of cucumber (Cucumis sativus L.) in solar greenhouse showed that the size of cells, chloroplasts, and starch grains and the number of chloroplast, grana, grana lamella and grana thickness of leaf chloroplast of cucumber increased with lowering leaf position. The microstructure of leaves and the ultrastructure of chloroplast of cucumber leaves were different because of the difference of temperature and sunlight among different months. In January, the light intensity was lower,and the cell size of cucumber leaves was larger than that in May, but the number of chloroplasts was less than that in May. The relationships between photosynthetic rate (Pn) and ultrastructure of chloroplast of cucumber leaves were not direct and very close. The Pn of the fourth leaf of cucumber was the highest, that of the first spreading out leaf was the second, and the near ground leaves had the lowest Pn.The primary reasons of the difference of Pn among different position leaves were that the leaf age and accepted light intensity were different. If different position leaves of cucumber accepted the same sunlight intensity, the difference of Pn among leaves of different positions would be smaller. Less efficient light hours and lower light intensity were the main factors influencing cucumber growth and yield in solar greenhouse. Comparatively, under sunny circumstance,the restriction of temperature on cucumber growth was very small, but in cloudy days, lower temperature induced by low light intensity became a key factor that restricted cucumber growth.

Validation of the ALMANAC model with different spatial scale

XIE Yun, James Kiniry, LIU Baoyuan

2003, (8):  1291-1295. 

Asbtract ( 914 )   PDF (731KB) ( 354 )  

The ALMANACmodel was validated in a drought stressed year and in a period from 1989 to 1998 at different sites of Texas to evaluate its ability in simulating maize and sorghum yields at different spatial scales and to extend its application range. There were 11 sites for maize and 8 sites for sorghum in plot size simulations, and 9 counties for maize and sorghum in county level simulations. The model showed similar accuracy in simulating both plot size and county level mean grain yields. It could also simulate single year yields under water limited climatic conditions for several sites and mean county yields of maize and sorghum, and had small CVvalues of mean yields for a long term prediction. The mean error was 8.9% for sorghum and 9.4% for maize in field scale simulations, and was only 2.6% for maize and 0.6% for sorghum in county level mean yield simulations.Crop models often require extensive input data sets to realistically simulate crop growth. The development of such input data sets is difficult for some model users. The soil, weather, and crop parameter data sets developed in this study could be used as the guidelines for model applications in similar climatic regions and on similar soils.

Effects of growing process and climatic conditions on grain quality of spring-sown wheat

WU Dongbing, CAO Guangcai, QIANG Xiaolin, LI Meng, WANG Xiufang, CHEN Heqin

2003, (8):  1296-1300. 

Asbtract ( 981 )   PDF (255KB) ( 374 )  

In the period of 1998～2000, 10 wheat varieties were used to study the effects of growth, development process and climatic conditions on the quality of wheat grains through spring sowing experiments in Beijing. The results showed that there were no significant variations on the quality traits among the varieties while there were significant variations among different years. The most significant negative correlation had been shown between the days from sowing to ripening and hardness of the grains and between the days from heading to ripening and the content of wet gluten of the grains. There was a significant negative correlation between day night temperature difference during the period from heading to ripening and content of NIR protein. The results also showed that there was most significant negative correlation between total radiation, day night temperature difference and the content of wet gluten of the grains. There was significant positive correlation between total sunlight and the content of wet gluten of the grains. The significant negative correlation was present between sedimentation value and total radiation, total sunlight, average temperature of daytime, day night temperature difference.

Temporal and spatial distribution characteristics of the crop root in intercropping system

ZHANG Enhe, HUANG Gaobao

2003, (8):  1301-1304. 

Asbtract ( 1036 )   PDF (405KB) ( 334 )  

The ecological mechanism of competition and compensation between the crop root systems of two different intercropping patterns, wheat-soybean and corn-cabbage, was studied by field experiment. The results showed that the annual growth peak of wheat soybean roots in intercropping was interlacing, the growth of root weight and length expressed synchronism, and the peak of root weight was appeared earlier than that of root length. The vertical distribution of the two crops' root system in two intercroppings was reduced gradually along with soil depths, which also showed that the multiple growth waves moved progressively. The root system distributed horizontally in intercropping system also showed a clearly unbalanced distribution. The root system distribution of out row for corn elongated 20.4～40.8 cm to cabbage rows, but that of cabbage elongated only 8.5～12.6 cm to corn. The cross extent of root systems in corn cabbage intercropping was decreased from 40.2 cm to 20.1 cm by fertilization, and the place of cross point for root concentrated region was changed from 20.5 cm to 12.4 cm below soil surface by fertilizer supply. The place of cross point for root concentrated region was an important index to decide the degrees of competition.

Multiplication technique of rice T(P)GMS line with double low critical temperature values using cold water irrigation

XU Mengliang, LIANG Manzhong, LIU Guiquan, CHEN Liangbi, ZHOU Guangqia, ZHOU Guanxiang, QIU Xiulan, HUANG Shiqi

2003, (8):  1305-1308. 

Asbtract ( 953 )   PDF (231KB) ( 288 )  

In this paper, cold water irrigation multiplication technique was used to solve the difficulty of multiplying rice TGM Sline 96-5-2S(Oryza sative L.) with double low critical temperature values under natural air temperature condition. The results indicated that irrigating rice TGMS line 96-5-2S with different temperature underground cold water from the stage of pistil and stamen primordia differentiation to the stage of pollen filling for 15 days, and keeping the water depth 18～22 cm, the seed set rate of 96-5-2S decreased with increasing irrigating water temperature. When the average temperature of irrigation water was 18.5～19.8 ℃, the seed set rate ranged from 40.5% to 57.6%, and the yield ranged from 3.30 t·hm^-2 to 4.35 t·hm^-2.While the temperature was 20.5～21.3 ℃, the seed set rate and yield sharply decreased to 2.5～10.4% and 0.21～0.90 t·hm^-2, respectively. When the average temperature was 22.3～23.5 ℃, both the seed set rate and yield were zero. Under the same irrigation water temperature (average 19.8 ℃) and the same irrigating period (phase Ⅳ to phase Ⅶ), the seed set rate and yield of 96-5-2S with deep water irrigation (18～22 cm) was very significantly higher than those of 96-5-2S with shallow water irrigation (7～10 cm). Under the conditions of same irrigation water temperature (average19.8 ℃) and same water depth (18～22 cm) but different irrigating periods (15 days from phase Ⅳ to phaseⅦ, 20 days from phase Ⅲ to phase Ⅶ, and 25 days from phaseⅡ to phaseⅦ), the difference of seed set rate and yield of 96-5-2S between15 day treatment and 20～25 day treatment was not significantly different. It is confident that 96-5-2S could multiply with underground cold water irrigation. The main technique index was that irrigating water temperature should be 18～20 ℃,irrigating period should be from phase Ⅳ to phase Ⅶ, and irrigating water depth should be 18～22 cm.

Photooxidation characteristics of super-hybrid rice "Liangyoupeijiu" and its parents

WANG Rongfu, ZHANG Yunhua, QIAN Lisheng, YU Jianglong

2003, (8):  1309-1312. 

Asbtract ( 862 )   PDF (678KB) ( 362 )  

With comparison of the differences of light absorption and active oxygen metabolism between super-hybrid rice "Liangyoupeijiu" and its parents, this paper provided a physiological foundation of matching and grouping for cultivating anti photooxidized hybrid rice. TPS-photosynthetic system and FMS2-fluorescence (Hansatech, UK) were used to respectively determine the photosynthetic rate and the chlorophyll fluorescence in the rice leaves that had been processed in artificial photooxidization. Meanwhile, the contents of chlorophyll, protein and malonaldehydic acid (MDA) as well as the activation of superoxide dismutase (SOD) and peroxidase (POD) were determined. The results showed that the photosynthetic rate of "Liangyoupeijiu" was 2.4% lower than that of its female parent, and 23% higher than that of its male parent. After eight days anti photooxidization process, its chlorophyll content was higher than that of its female parent by 33%, protein by 15%, initial photochemical efficiency by 30%, SOD by 32% and POD by 100%, while its photochemical quince coefficient was lower than that of its female parent by 9% and MDA by 50%. It showed that there was not much difference between the filial generation and its male parent. The super hybrid rice "Liangyoupeijiu" was very efficient for solar energy utilization under the condition of photooxidization, and had outgrown its parents in the aspect of anti photooxidization.

Effect of iron oxide addition on hydrogen, carbon dioxide and methane geneses in paddy soil

QU Dong, ZHANG Yiping, S. Schnell, R. Conrad

2003, (8):  1313-1316. 

Asbtract ( 961 )   PDF (558KB) ( 438 )  

Paddy soil is an important contributor for atmospheric methane. The methanogenesis is related to the production of acetate, hydrogen and carbon dioxide during the decomposition of organic matter under anaerobic conditions. As electron acceptors, iron (Ⅲ) oxides can effectively compete with electrons in the transformation of organic matter into methane. Its mechanism maybe relates to the consumption of H₂ and CO₂. After added ferrihydrite and lepidocrocite, the H₂, CO₂ and CH₄ were determined during the anaerobic incubation of slurries at 25 ℃ for 105 days. The results indicated that the addition of ferrihydrite and lepidocrocite could greatly decrease the concentration of H₂, CO₂ and CH₄, and ferrihydrite had a stronger effect than lepidocrocite. In this system, the balance of organic-C was disturbed, CH₄-C and CO₂ Cwere reduced, but the CO₃^2--C fixed by slurry was greatly increased.

Integrated evaluation of eco-agricultural practices in Deqing County, Zhejiang Province

CHEN Jie, HU Bingmin

2003, (8):  1317-1321. 

Asbtract ( 911 )   PDF (259KB) ( 253 )  

Integrated index method was used to evaluate the practices of eco agriculture in Deqing County in 1990～1998. The results showed that the integrated benefit, resources use, and ecological, economic and social benefits appeared a rising trend.The value of integrated benefit index in 1998 was 2.36 times of that in 1990.The benefit index, however, also fluctuated in these years, which meant that the eco agricultural system of Deqing County still had some problems to be resolved.Adjusting industry structure in rural areas, lessening pollution produced by rural industry,and improving stability of eco agricultural system should be highlighted in the next stage.

Effect of enhanced UV-B radiation on competition among several plant species

YUE Ming, WANG Xunling

2003, (8):  1322-1326. 

Asbtract ( 972 )   PDF (796KB) ( 389 )  

The effect of enhanced UV-B radiation (280～315 nm, approximating a 15% ozone layer reduction) on competitive interaction between spring wheat (Triticum aestivum) and wild oat (Avena fatua) was examined in the field. The density dependent mortality of both wheat and wild oat did not exhibit a significant difference between control and UV-B treatments. Arelatively high degree of competitive stress enhanced the effect of UV-B stress on biomass reduction.Under UV-B enhancement,the relative competitive status of wheat in terms of total biomass and aboveground biomass increased,but decreased when based upon grain production. Shifts in competitive balance occurred with significant changes in total biomass, especially when plants grew at higher densities in monocultures and mixtures. There were different effects in direction and intensity of UV-Bradiation on competition balance of the other three species pairs, but in general, the effect of UV-Bwas in favor of monocotyledonous. The results implied that total degree of competitive stress,especially interspecific competition,might be crucial to assess the effect of UV-B enhancement on agriculture ecosystem properly.

Effects of grazing, cutting and decapitating on grass populations on the artificial grassland in subtropical zone of China

BAO Guozhang, LU Guanghua, GUO Jixun, BAO Jianyin

2003, (8):  1327-1331. 

Asbtract ( 943 )   PDF (496KB) ( 384 )  

Studies on the effects of grazing, cutting and decapitating on grass populations on the artificial grassland in the subtropical zone of China showed that moderate grazing and cutting could increase the adaptability of Dactylis glomerata and Lolium prenn due to decapitating. Decapitating could rescind the apical dominance and reproduction growth of grass, and hence,the ecological effects of grazing and cutting on grass could be realized by decapitating, and the population density, caloric value and energy accumulation of Dactylis glomerata and Lolium prenn increased obviously. Apical dominance of grasses could lower the population density, energy accumulation and intra population competitive ability.

Clonal growth of stoloniferous herb Potentilla anserina on degraded and non-degraded alpine meadow soil

SHEN Zhenxi, CHEN Zuozhong, WANG Yanhui, ZHANG Jingli, ZHOU Huakun

2003, (8):  1332-1336. 

Asbtract ( 1029 )   PDF (630KB) ( 353 )  

The clonal growth of Potentilla anserina on degraded and non degraded Kobresia humilis meadow soil was studied by a transplanting experiment in the field. No significant differences in numbers of stolons, height, and leave size per mother ramet were observed between the two soils, but the numbers of leaves per mother ramet, length and width of stolon,and spacer length were significantly different. There were more leaves per mother ramet, longer stolon and spacer, and wider stolon on degraded soil, where available nutrient was poor than in non degraded soil. Under degraded alpine meadow soil condition, the clonal plant species might produce much more photosynthetic product to support stolon growth by the increase of leave numbers per mother ramet,and the longer and wider stolon could intensify the foraging ability of the mother ramet that would benefit to daughter ramet. Both mother and daughter ramet of Potentilla anserina invested much more biomass to their underground part (root system) in non degraded soil to increase the survival rate of daughter ramet.

Optimizing of pastures grazing pattern with biomass growth and consumption models

YE Xujun, CHEN Jie, WANG Zhaoqian

2003, (8):  1337-1342. 

Asbtract ( 1062 )   PDF (317KB) ( 247 )  

This paper discussed the biomass growth and consumption processes in grazed pasture ecosystems from a theoretical point of view, simulated the dynamics of these two processes with mathematical models, and analyzed the mechanism of ecological balance in pasture ecosystems from the perspective of these two processes. With the proposed biomass growth and consumption models,the dynamics of cumulative biomass consumption during one production cycle was simulated, and the optimal grazing strategies of pastures were proposed. The results could be valuable for pasture grazing management in practice.

Factors restricting growth of heterotrophic bacteria in the water body of West Lake, Hangzhou

WU Genfu, YANG Zhijian, ZHOU Xueping, WU Jie

2003, (8):  1343-1346. 

Asbtract ( 1080 )   PDF (550KB) ( 354 )  

Restricting factors of bacteria growth were studied by pure culture and natural culture test. The results showed that organic carbon source available for bacteria was more important than (NH₄)₂SO₄ and KH₂PO₄, while higher pH, and rich biomass of phytoplanktons and zooplanktons in the water restrained the growth of heterotrophic bacteria. Under natural culture experiment, Azotobacter increased after 0.5% glucose was added, and a lot of mildew grew after adding0.5% glucose with 0.1%(NH₄)₂SO₄ and 0.1% KH₂PO₄, while Pseudomonas enriched 30～57% after adding0.01% beef extract. It was also showed that bacteria growth potentiality in natural water could reach to 10⁵cfu·ml^-1.

Multianalysis between chlorophyll-a and environmental factors in Qiandao Lake water

LU Huanchun, WANG Feier, CHEN Yingxu, YU Zuoming, FANG Zhifa, ZHOU Gendi

2003, (8):  1347-1350. 

Asbtract ( 1194 )   PDF (580KB) ( 550 )  

In this paper,the regression equation between chlorophyll-a (Chla) and some environmental factors was calculate by multiple stepwise regression,based on the monthly monitoring data in the Qiandao Lake from Jan.1999 to Dec.2000, and modified Carlson trophic state index for all the sampling sites was also analyzed.The results indicated that the spatial and temporal distribution of chlorophyll a in the sampling sites were varied strongly, the concentration of chlorophyll a in the Xin'an river changed from 50 mg穖^-3 to 30 mg穖^-3, but that in the lake was under 5 mg穖^-3. The modified Carlson trophic state index (TSI_M) for the sampling sites in southeast of the lake was under 37 (belonging to olligotrophic), and the others were under 53 (belonging to mesotrophic). In different sampling sites, the significant environmental affecting factors for chlorophyll a were different.However, the relationships between chlorophyll a and water temperature and total phosphorus were positive,and that between chlorophyll a and diaphaneity was negative.

Effects of rehabilitation of submerged macrophytes on nutrient level of a eutrophic lake

WU Zhenbin, QIU Dongru, HE Feng, FU Guiping, CHENG Shuiping, MA Jianmin

2003, (8):  1351-1353. 

Asbtract ( 1129 )   PDF (325KB) ( 699 )  

The effects of rehabilitation of submerged aquatic vegetation on nutrient level of eutrophic waters were investigated by using large scale enclosure system installed in a hyper-eutrophicated lake, Lake Donghu of Wuhan. The concentrations of total nitrogen (TN) and total phosphorus (TP) of the enclosures with artificially recovered submerged macrophytes were significantly lower than those of the macrophyte free control enclosure and the lake water, and the TPof macrophyte enclosure was found to be around 0.1 mg稬^-1 and relatively stable. The concentration of ammonia and nitrite of the macrophyte enclosures were lower than those of the control and the lake water. However, the nitrate concentrations did not differ among the various water bodies. It was demonstrated that re establishment of submerged macrophytes could efficiently reduce the nutrient level and thus control the overgrowth of the undesirable algae and improve water quality in the eutrophic lakes.

Sublethal effects of insecticides on fecundity of multicolored Asian ladybird Harmonia axyridis

WANG Xiaoyi, SHEN Zuorui, XU Wenbing, LU Jian

2003, (8):  1354-1358. 

Asbtract ( 1136 )   PDF (736KB) ( 383 )  

The effects of sublethal doses of 6 insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on the fecundity of multicolored Asian ladybird Harmonia axyridis were determined respectively. The results showed that in all treatments,the daily average number of eggs per female ladybird was about 40～55. Ladybirds pretreated with imidacloprid by contact and feeding methods, and with rotenone by feeding method produced significantly fewer eggs,compared with control. But the accumulative oviposition of ladybirds pretreated with 6 insecticides at sublethal level was no significant differences,compared with untreated ladybirds. The hatching rates of the eggs laid by ladybirds pretreated with 6 insecticides by two methods were all lower than that of control. The accumulative survivals from egg to pupal stage of all treatments decreased significantly. The developmental duration from egg to pupa of those treated with imidacloprid by two methods and with fenvalerate by contact method prolonged significantly, while that of those treated with rotenone by two methods and with fenvalerate, abamectin, pirimicarb, and azadirachtin by feeding method shortened obviously, but that of those treated with rotenone and abamectin by contact method had no differences with control. After the eggs were immersed with sublethal concentrations of imidacloprid, rotenone, fenvalerate and abamectin, the successful hatching rates were all lower than that of control, and the development periods prolonged clearly. The 1st instar larval survival rates of those treated with fenvalerate decreased significantly,and the survivals from 2nd instar larval to pupal stage also reduced to some extent. The total developmental duration of those treated with rotenone and fenvalerate prolonged significantly. These findings suggested that the effects of insecticides at low doses on the fecundity of ladybird were very complicated. The class, action mode,toxicity and exposure route of insecticides could affect the results of experiments.

Chaotic diagnosis of Nilaparvata lugens occurrence system

XU Xiaofeng, MA Fei, ZOU Yunding, CHENG Xianian

2003, (8):  1359-1362. 

Asbtract ( 914 )   PDF (247KB) ( 248 )  

It is estimated that there are nearly 20 million hectares of rice crop being infested by Nilaparvata lugens, with an annual loss of some half a million tones of grain. In order to study the properties and laws of Nilaparvata lugens occurrence system further, the time series data of Nilaparvata lugens occurrence from 1986 to 1998 collected in Taihu Lake District were analyzed by using the methods of autocorrelation function, power spectrum figure, phase trajectory figure, poincare section, and return map of chaos theory. The results indicated that Nilaparvata lugens occurrence system in Yangtze River valley area in China had an obvious chaotic property, even though there was some interference of random noises.

Landscape pattern of Nanjing urban-rural ecotone

CHEN Caihong, HU Feng, ZHANG Luochen

2003, (8):  1363-1368. 

Asbtract ( 933 )   PDF (534KB) ( 312 )  

Landscape ecological characteristics of the urban-rural ecotone of Nanjing City were studied by using remote sensing and geographical information system (GIS) techniques. Two representative study regions with the same area were chosen in the eastern and southern part of the city. The urban-rural fringe of both east (URFE) and south region (URFS) can be divided into three zones: fringe-paraurban zone, transition zone and pararural zone. URFE was basically characterized by low landscape diversity, dominance and fragmentation. The forest patches in URFE had larger area and average perimeter, while their average fractal dimension, average stretched index and separated degree were lower. The average area of vegetable land and paddy land was larger than that of south region. URFS showed higher landscape diversity, dominance and fragmentation, more and higher density of patches. The area and the perimeter of water and architectural patches in URFSwere also larger than that of URFE. The relationship between patch area and fractal dimension, stretched index and fractal dimension, patch number and area were discussed. The function and contributing factors of each type of patches, especially forestland, and the landscape characteristics and the ecological significance of corridors including road, river, and city wall of urban rural fringe were also analyzed.

Effect of transgenic plants on biodiversity of agroecosystem

NIE Chengrong, WANG Jianwu, LUO Shiming

2003, (8):  1369-1373. 

Asbtract ( 1023 )   PDF (776KB) ( 803 )  

The effect of transgenic plants on the biodiversity of agroecosystem is an important environmental issue. There are many researches in this field at home and abroad recently. This paper reviewed the advances of the researches based on three levels of biodiversity as genetic diversity, species diversity and ecosystem diversity. They included following aspects: the effect of insect-resistant transgenic crops on target pest; the effect of herbicide resistant transgenic crops on crops and wild weedy relatives; the effect of virus resistant transgenic crops on virus; and the effect of transgenic crops on non-target organisms. This paper also discussed the effect of transgenic crops on soil ecosystem and crop genetic diversity. Their potential risks included uncontrolled flows of genes to wild relatives; development of herbicide, insect, and virus resistance in wild relatives; reduced crop genetic diversity; and adverse effects on organisms that were not pests, such as beneficial insects.

Origin of SARS from accelerated evolution of a virus by combined pollution

ZHOU Qixing, WEI Shuhe, ZHANG Qianru, ZHONG Ming

2003, (8):  1374-1378. 

Asbtract ( 1039 )   PDF (278KB) ( 397 )  

The SARS virus origin which obviously differs from the theory of out-space origin and the theory of wildlife origin was theoretically discussed based on principles of pollution evolution ecology,pathogenesis and infectant characteristics of SARS,and some relevant experimental evidence. It emphasizes on the fact that increasingly combined pollution in China provides a substantial basis for virus evolution. Gene recombination and fusion of more than one virus in ecosystems should take charge with the origin of a SARS virus. In particular,a common cold or influenza virus can acceleratedly changed into a superpower common cold or influenza virus through genetic mutation and gene recombination by increasingly combined pollution. This work can be useful for human beings to overcome SARS in theory.

Effect of plants on methane production, oxidation and emission

DING Weixin, CAI Zucong

2003, (8):  1379-1384. 

Asbtract ( 943 )   PDF (838KB) ( 458 )  

The paper reviewed the role of plants in the processes of methane production, oxidation and emission in soils. It was the abilities of different plants to excrete the quantity and quality of root exudates that resulted in discrepancies of methane production among plants and in plant growing seasons. The oxygen magnitude of the downward transport through the plant aerenechyma, which, in turn, also acted as a conduit for methane from the soil to the atmosphere, affected endogenous methane oxidation capacity with plants and with plant growing seasons. Plant through changing amount and density of plant aerenchyma altered its ability to transport methane from soil to atmosphere. In addition to soil properties, flux and pattern of methane emission from soils largely depended on plant abilities to excrete exudates and oxygen, and transport methane in different plant growing seasons.

Effects of land use change on carbon storage in terrestrial ecosystem

YANG Jingcheng, HAN Xingguo, HUANG Jianhui, PAN Qingmin

2003, (8):  1385-1390. 

Asbtract ( 1092 )   PDF (1042KB) ( 671 )  

Terrestrial ecosystem is an important carbon pool, which plays a crucial role in carbon biogeochemical cycle. Human activities such as fossil fuel combustion and land use change have resulted in carbon fluxes from terrestrial ecosystem to the atmosphere, which increased the atmospheric CO₂ concentration, and reinforced the greenhouse effect. Land use change affects the structure and function of the terrestrial ecosystem, which causes its change of carbon storage. To a great extent, the change of carbon storage lies in the type of ecosystem and the change of land use patterns. The conversion of forest to agricultural land and pasture causes a large reduction of carbon storage in vegetation and soil, and the decrease of soil carbon concentration is mainly caused by the reduction of detritus, the acceleration of soil organic matter decomposition, and the destroy of physical protection to organic matter due to agricultural practices. The loss of soil organic matter appears at the early stage after deforestation, and the loss rate is influenced by many factors and soil physical, chemical and biological processes. The conversion of agricultural land and pasture to forest and many conservative agricultural practices can sequester atmospheric carbon in vegetation and soil. Vegetation can sequester large amounts of carbon from atmosphere, while carbon accumulation in soil varies greatly because of farming history and soil spatial heterogeneity.Conservative agricultural practices such as no tillage, reasonable cropping system,and fertilization can influence soil physical and chemical characters, plant growth, quality and quantity of stubble,and soil microbial biomass and its activity,and hence, maintain and increase soil carbon concentration.

Ecological adaptability and application safety of Epiblema strenuana as a biocontrol agent against ragweed

MA Jun, WAN Fanghao, GUO Jianying, YOU Lanshao, YANG Hanmin

2003, (8):  1391-1394. 

Asbtract ( 1048 )   PDF (553KB) ( 370 )  

Epiblema strenuana is the most important natural enemy against Ambrosia artemisiifolia, A. trifida and Parthenium hysterophorus.In this paper,its ecological adaptability and application risk as a biological agent against ragweed was analyzed and reviewed. Epiblema strenuana had a restrict host specificity, with all the field hosts belonging to Ambrosiinae, and its selective risk on sunflower and chrysanthemum was less than0.01 or/and zero (no risk). 15～35 ℃ was the suitable temperature regimes for E. strenuana to develop, and lower constraint temperature could reach -8～-12 ℃. The population size of this insect could increase 23 and 4 times on A. artemisiifolia, A. trifida and Xanthium sibiricum after each generation, respectively. In the field, the infected plants had an average of 20～30 galls per plant, and died with 5.2 and 26 galls before and after rosette stage.The spread distance of this moth within12 months after release was more than100 km. It indicated that E.strenuana was an effective and safe agent for cereal and economic crops, ornamental plants, and indigenous natural enemy in the introduced region.

Construction and important factors analysis of natural life table of diamonthback moth, Plutella xylostella under pesticides treatment

LIU Xin, YOU Minsheng

2003, (8):  1395-1397. 

Asbtract ( 970 )   PDF (260KB) ( 326 )  

The natural life tables of diamonthback moth (DBM), Plutella xylostella under pesticides treatment were constructed,and the construction method of item "pesticide" was particularly discussed.The life tables indicated that the indices of population trend (I) under the treatment with 80% Dichlorvos EC 1000x and the contrast were 0.7796 and 1.4804, respectively,showing that Dichlorvos had some control on DBM. But,Dichlorvos had some effects on natural enemies of DBM. The decrease of parasitism rate at pupa stage was most obvious,which indicated that Dichlorvos had some effects of killing and wounding on the natural enemies of DBM.