中国生态农业学报(中英文)

Isolation of a germination stimulant for striga hermonthicu (Del)Benth from root culture of Menispermum dauricum DC

MA Yong-Qing, Shinobu iNANAGA, Yukihiro SUGiMOTO, Babiker A.G.T.

2003, 11(1): 1-5.

Abstract(943) PDF(799)

Abstract:
In this paper the isolation and purification of Striga kermontkica germination stimulant from Menispermum daurlcum DC．root culture filtrate are reported．Purification and isolation were undertaken by absorption of the stimulants onto XAD-4,solvent partitioning into ethyl acetate，and further separation on Sephadex LH20，C18 Sep-Pak Cartidge；preparative and analytical HPLC columns．Each step involved in the isolation procedure was followed by a bioassay using conditioned Striga hermonthica seeds．Three stimulants were detectcd in the filtrate． on HPLC the major stimulant showed similar chromatographic behavior and CO-eluted with authentic strigo1． Furthermore,its UV and Mass spectra were similar with those reported for strigol and strigol-like molecules． In this study，albeit no novel Striga germination stimulant was isolated from M ．dauricum root culture，the investigation represents the first report on isolation of strigol or strigol-like molecule from tisue culture．Moreover，it provides unequivocal evidence that strigol and strigol-like moleculas are of plant origin．

Study on prediction models of beginning period of Empoasca vitis activity peak

LIN Wen-Hao, CHEN Chao-Ying, LIN Nai-Quan

2003, 11(1): 6-9.

Abstract(1434) PDF(959)

Abstract:
Based on establishing the combinative prediction models AR (P)of the linear regression and time series，a method for prediction of beginning period of activity peak of Empoasca vitis next year，by using observed values of climatic factions in last year，was proposed．Therefore one can advance the announcement date of pest disaster explosion．The prediction practices in Fu’an tea field，Fujian Province，indicate that this combinative prediction method is a feasible mean ．

Studies on physiobiochemical characteristics of grain-filling in different types of rice(Oryza sativa L．)

HUANG Jin-Wen, LIANG Yi-Yuan, LIANG Kang-Jing, LIN Wen-Xiong

2003, 11(1): 10-13.

Abstract(1472) PDF(1189)

Abstract:
Three different rice cuhivars，characterized by 3 larger panicle type，such 3S new plant type rice“IR_65600.85”、“Peiai64S／E32”and“Eryou86”are used in the experiment to investigate the grain-filling characteristics and the changes 0f the relevent physioehemical activity．The results show that the superior grains of rice in each entry have higher initial growth power than the inferior grains，in turn entering active grain-filling stage earlier；the superior grains also perform higher activities of ADP-glucose pyrophosphorylase and starch synthase than the inferior grains in each entry during the early stage of grain-filling，it is helpful to promote the transpo rtation of dry matter into the superior grains；there are differences in genotypes in the case of the physiochemical activities ，among the three rice cultivars concerned，“IR_65600.85”exhibits its poor physiochemical activities ，consequently decreases percentage of filled grains and yield．

Effects of different nutrient treatments on the senescence of rice leaves

YANG Chang-Ming, YANG Lin-Zhang

2003, 11(1): 14-16.

Abstract(915) PDF(898)

Abstract:
The effects of different nutrient treatments on photosynthetic characteristics，metabolism of active oxygen of rice flag leaves in the latter stage are studied．The results show that the combined application of organic and inorganic manures，especially barn yard manure and chemical fertilizers can significantly delay the decomposition of chlorophll and the decrease of photosynthetic rate of rice flag leaves．In the meanwhile，the activities of superoxide dismutation(SOD)and catalase(CAT)and the increase of content of malondialdehyde(MDA)are controlled and adjusted resulting in the increa ses of the grain weight and grain yield．

Analysis on photosynthesis characteristics in rice under different irrigations

ZOU Jun, XIE Xiao-Li, WANG Kai-Rong

2003, 11(1): 17-19.

Abstract(1008) PDF(1022)

Abstract:
The cumulation photosynthesis effect in the condition of different irriganons on the paddy has the different resuits．The contrast of colony photosynthesis efficiency after heading between different irrigations in the paddy is notable but very little in the early paddy．The midday depression always appears regardless of the sunny days or cloudy days in the condition of normal irrigation．The photosynthes is reaches the peak values at 9 o’clock and 15 o’clock in the cloudy days，and at 11 o’clock and 17 o’clock in the sunshine days．Data indicate that the air humidity and the concentration of C0₂ are the two dominant environmental factors affecting the photos ynthesis peak value．The peak value of Tianguan appears ahead of time by the other measurements in the sunshine days，but it has the nearly reversed result in the cloudy days．of the four kinds of irrigation，Tianguan has the weakest photosynthes is velocity，Yanguan has the strongest，and Peiguan stands in the middle．

Effect of high temperature on the physiological characteristics of casaba

YANG Qiu-Zhen, LI Jun, WANG Jin-Xia, CHEN Zhang-Ming

2003, 11(1): 20-22.

Abstract(1085) PDF(1005)

Abstract:
Effect indexes of high temperature forcing on casaba and its physiological reasons are revealed through contrast experiments during its reproduction growth period．Results show that high temperature being higher to equal as 40℃ does harm tO casaba during its reproduction growth period，and its harmed degree has a direct ratio to high temperature intensity and duration．Damaged temperature of pollen avidity is much lower than that of lamina；that of lamina cell theca is higher or equal to 50℃ ，that of chlorophyll is higher or equal to 41℃ ，temperature that has the effect on pollen avidity is higher or equal to 31℃ ．Temperature higher or equal to 52℃ does obvious harm to nutrition and procreation organs of casaba．Experiment show that the leaves conductance rate increases ，chlorophyll content and farina vigor decline with the prolongation of the high temperature days．Treated with high temperature for 3 days，conductance rate of leaves at interspace and undersurface is 70％ more than antitheses．1eave chlorophyll content is 20％ less than antitheses and the percentage of high farinavigor is only 20％．1ess 1／2 than antitheses by I-KI coloration．

Effects of environmental factors under shading conditions on water use efficiency of tomato leaves

LIU Xian-Zhao, KANG Shao-Zhong

2003, 11(1): 23-26.

Abstract(981) PDF(953)

Abstract:
Effects of all parameters influenced by the three levels of shading (0％ shading，HL；75％ shading，LL；40％shading．ML)on water use efficiency(WUE)of tomato leaves grown in pots under well-watered conditions were investigated in summer sunny midday．The results show that environmental factors influence WUE synthetically and complexly．especially，stomatal resistance and vapor pressure difference(VPD)．The stomatal resistance and the VPD increase by high evaporation potential because strong light and high temperature at noon at HL are more grea ter than those at ML and LL treatments．The increase in stomatal res istance can increase WUE，but the increase of VPD can decrease WUE．Daily variations of WUE under three shading levels show shallow “L” type，which are caused by the non-sym metry of diurnal variations of environmental factors and interaction of two mechanisms above．Compared with the non-shaded control，the average single leaf WUE of 40％-shaded plants increases by 22．9％ during the 12：O0～15：00 in summer sunny day，while the WUE for 75％-shaded plants reduces significantly by 28．1％．showing that moderate shading can enhance WUE of tomato leaves under sufficient water condition on summer midday．

The changing of water transfer potential in soil-plant-atmosphere continuum system of maize field

YANG Xiao-Guang, LIU Hai-Long, YU Hu-Ning

2003, 11(1): 27-29.

Abstract(1163) PDF(1004)

Abstract:
By measuring the water potential of fixed points and sites in different interfaces of the SPAC system of maize field in North China Plain，the resistance of water transferring is calculated．The results show that atmospheric water Potential and leaf water potential have obvious daily variation．The maximum water potential appears before sun rising；the daily atmospheric water potential changes violently，and the soil water potential changes relatively little，mainly under the influence of the soil water content．There exists a grade of water potential that gradually decreases up forward within the plant of summer maize．In the course of water transmission in SPAC system，different interfaces show obvious grades of water potential and great resistance．The resistance from leaf to atmosphere is much more than that from soil to leaf．implying that the resistance of leaf-atmosphere plays a key role in the restriction and adjustment of the dissipations rate and quantity of water from plants．

Development of cytoplasmic herbicide resistance foxtail millet and its difference to the susceptible general varieties

JI Gui-Su, DU Rui-Heng, GAO Zhan-Cheng

2003, 11(1): 30-32.

Abstract(1550) PDF(923)

Abstract:
The development characters of cytoplasmic herbicide resistance foxtail millet“097 1”is studied taking the susceptible general variety “Yugu 2”as the control in this paper．The results show that the development of“0971”is slower than that of“Yugu 2”in early stage．the head stage is later too．But it grows faster at the later stage and most of the characters get the same level compared to “Yugu 2”．The head weight of“0971”is lighter than that of“Yugu 2”because of the later head stage and the slower milking speed．

Analysis on relation between the yield and the components of“Shanyou 63” under different yield levels

YANG Cong-Dang, HE Qing-Rui, ZHENG Xue-Yu, HUANG Qing-Yu, ZHU De-Feng

2003, 11(1): 33-35.

Abstract(1208) PDF(993)

Abstract:
Hybrid rice，“Shanyou 63”，of which the yields are from 7.1 to 15．5t／hm²，is used to analyze the relation between the yield and its components．and its determinants．The results show that grain yield is mainly determined by the number of spikelets and filled grains per m²． When grain yield is less than 12t／hm²，it increases with the increase of spikelets per panicle：when it is more than 12t／hm²，it increases with the increase of panicles per m²．When the number of spikelets per m² is less than 55000，the number of spikelets increases with the number of spikelets per panicle．Conversely，it increases with the number of panicles per m²．The relationship between weight of grains per panicle and the number of spikelets per panicle is of positive correlation．The weight of grains per panicle increases by 0．0241g with the increase of one spikelet per panicle．

Effect of Arbuscular mycorrhizal fungi on yield of peanut and sweet potat

LIU Run-Jin, LI Min, SHI Zhao-Yong, HAN Yi-Zhou, LI Xiao-Lin

2003, 11(1): 36-37.

Abstract(1559) PDF(1081)

Abstract:
Effect of arbuscular mycorrhizal(AM)fungi Glomus versiforme Berch and mixed inocula[Glomus mosseae Nicolson and Gedermann+Sclerocystis sinuosa(Gerd．Bakshi)Almeida and Schenck]on growth and yield of peanut and sweet potato were investigated under field conditions．Results show that AM fungi can improve health status of pea nut seedlings and the number of fruits per plant．increase 21．3％ of yield per hectare compared to the contro1．However the growth and yield of sweet potato are not increased，and its plant length and weight of stem with leaves are reduced by the inoculation with Glomus versiforme，while the vegetation growth and the numbers of fruits per plant are significantly enhanced by inoculation with the mixed inocula of AM fungi，and the yields per plant and per hectare are 1．6 and 1．4 times respectively greater than those of the contro1． It is suggested that the different species of AM fungi should be used for various crops when applied in field．

The innuence of vegetable wilt(Fusarium oxysporum f．sp．)preventing-antagonistic microorganisms(Bacillus sp．)on the activity of some enzymes in plants

GAO Fen, HAO Bian-Qing, MA Li-Ping, QIAO Xiong-Wu

2003, 11(1): 38-40.

Abstract(962) PDF(759)

Abstract:
Liquid cultures of antagonistic microorganisms(Bacillus sp．)were made．Changes of the activity of several enzymes in cucumber，watermelon，sweet pepper treated with the liquid culture were investigated also．The results show that compared with the activities of the control plants，those of the polyphenol oxidase，catalase，B-1，3-dextranase in the plant treated with the liquid cultures are on an obvious rise．Increasing rates of polyphenol oxidase activity in sweet pepper treated with 98-Ⅱ and in cucumber treated with 96-Ⅱ are 477．78％ and 150．O0％ respectively．Increasing rates of catalase activity in cucumber treated with 96-Ⅱ and 94-II are 419．64％ and 115．66％ respectively．Increasing rate of catalase activity in watermelon treated with 94-Ⅱ is 109．24％．Increasing rate of B-1，3-dextranase activity in cucumber treated with 98-I 23．90％．

A study of paclobutrazol(PP₃₃₃)on conservation of sweet potato germplasm in vitro at normal temperature

ZHANG Xi-Tai

2003, 11(1): 41-43.

Abstract(1082) PDF(1145)

Abstract:
Treated“Xushu 18”plantlets in vitro with PP₃₃₃ in each concentration between 3．6～36．0umol／L，the growth potential is decrea sed．but the content of chlorophyll and root-shoot ratio are increased．“Xushu 18” plantlets in vitro on the“MS+IBA0．984umol／L”medium can be kept for above one year by adding PP₃₃₃” in each concentration between 0．216～28．8umol／L．If exogenous GA₃ is added in“MS+IBAO．984umol／L”medium．the growth rate of sweet potato plantlets in vitro will return to normal leve1．The best concentration of GA₃ is 0．289～0．434umol／L．

Techniques and integrated study of rice precision farming

XIE Gao-Di, CHEN Shen-Bin, QI Wen-Hu, YANG Xing-Wei, LIU Cheng-Liang

2003, 11(1): 44-47.

Abstract(914) PDF(1116)

Abstract:
The information process system and assessment system of environmental effect for precision rice plantation and the artificial intelligence system for measure of grain yield installed in combine harvester are designed and completed．Now the systems and the technique of precision agriculture have been used in demonstration site in the Experiment Basis of Shanghai Precision Agriculture．Based on the idea of spatial-oriented，object-oriented，user-oriented，the Farming Geography Information System for precision paddy plant is developed，which is characterized by network，intelligence and visualization．The Decision-making Management System is integrated by rice growth model and expert model for rice culture．The DGPS，RS，GIS，sensors and computer technique are adopted in building the artificial intelligence system for measure of grain yield installed in combine harvester，so the combine harvester can provide the grain yield and its distribution for site．

Study on soil sampling for precision agriculture-A case study from Shanghai Experimental Demonstration Base

QI Wen-Hu, XIE Gao-Di, DING Xian-Zhong

2003, 11(1): 48-52.

Abstract(1074) PDF(1336)

Abstract:
It is significant to explore the spatial variation of soil biochem istry characteristic by densely soil sampling，to construct the mathematical models for revealing the relation between crop yield and its environment for precision agriculture, to raise the resolution of soil maps through indirect methods and evaluate its reliability． Based on the evaluation of interpolation methods， this paper adopts Kriging interpolator to produce soil map of organic matter in Shanghai Base，using 280 soil samples of systematic sampling of 3 samples per hectare．The comparison between Kriging and inverse distance function interpolating is carried out by using the same data set，showing that the Kriging interpolator is better than the latter in this situation．This study also analyzes the scenario of producing soil maps by reducing the amount of samples and gives the relevant evaluations． Based on these analyses， the authors present the procedure of optimal design of soil sampling for precision agriculture of rice growing．

The optimum application of nitrogen on rice in precision agriculture

XUE Zheng-Ping, YANG Xing-Wei, DUAN Xiang-Suo, DING Mei-Hua

2003, 11(1): 53-55.

Abstract(998) PDF(1155)

Abstract:
The relation between the total application of nitrogen(N)and the crop data such as the leaf area index (LAJ)，the dry matter accumulation and the components of the yield is analyzed according to the data got from the field experiments．Then the model of relation between the total N and the rice yield is established．The line of the relationship between the total N and the rice yield diversifies like a parabola，which means that with the total N increa sing ， the yield increases ，but after the total N increases to a certain value，the yield descents．That is，the return from the deal gradually decreases．The test of total N applied on the farmlands of higher fertility and lower one indicates that their optimum applications of N are quite different from each other．

Comparison of interpolation methods for content of soil available phosphor

XIAO Yu, XIE Gao-Di, AN Kai

2003, 11(1): 56-58.

Abstract(1202) PDF(1147)

Abstract:
Using the spatial variations of soil and the interpolation methods and with the sampling interval of 60m ×60m，the experiment gets 280 sample data about organic matter content，available P，available K ，total N ，total P and soon．And with the interpolation methods，such as inverse distance weighted，global polynomial，local polynomial，radial basic function，simple Kriging，universal Kriging and ordinary Kriging(exponential model，spherical model，Gauss model and stable mode1)，the soi1 available P of 140 samples are interpolated and the consecutive spatia1 distributions in different interpo lation methods are obtained．Comparing the prediction values with another 140 samples，the interpolation methods like local polynomial，global polynomial and three kinds of Kriging are better，and the exponential model，spherical model and Gaus model of ordinary Kriging are much better，and the local polynomial is the best one of all methods．

Mapping of variable rate fertilizing and model of fertilizer application in paddy field

WANG Jin-Fang, LI Ben-Yin, YAN Ting-Me

2003, 11(1): 59-61.

Abstract(1288) PDF(1118)

Abstract:
To obtain basic information for variable rate fertilizer for rice production， spatial variability of soil chemical properties is evaluated in a slight alkaline paddy field of approximate 130hm²．Two hundred and eighty-one surface soil samples(0～20cm)are collected from each of the 75m × 75m plots after harvest to investigate the spatial variability of their chemical properties such as organic matter， hydrolysis nitrogen，available phosphorus， and available potassium．Geostatistical analysis is carried out to examine within-field spatial variability using kriged maps and the contour maps of soil nutrients are charted．Mathematic model of variable rate fertilizing is established according to the criterion of soil nutrient，function of fertilizer and yield of paddy．The experiment shows that the yield of paddy can be stably retained in 8250～9000kg／hm² by the adopted variable rate fertilizing.

Study on relation model between soil nutrient and rice yield in Shanghai Precision Agriculture Demonstration Base

DUAN Xiang-Suo, XUE Zheng-Ping, YANG Xing-Wei, LU Xian

2003, 11(1): 62-65.

Abstract(1340) PDF(1175)

Abstract:
According to the actual field data in Shanghai Precision Agriculture Demonstration Base，this paper analyzes the relation between the soil nutrient and the rice yield with the main composition method．The results show that the relation between the yield and the soil nutrient such as the total nitrogen (N)is positive correlation．Among them the yield reaction is sensitive to the content of phosphor(P)in soil while the pH and the salt have negative correlation with the yield．Further analysis of the main composition method shows that among the main composition the available N has the main function． In the sour alkali characteristics，the pH shows the character of sour alkaline of soil most obviously．Absolute error of soil nutrient-paddy rice yield model that is established with the main composition analytical method is 406．5kg／hm²．and the relative error is 4．88％．so the result is good．

Design of farmland GIS for precision agriculture

AN Kai, XIE Gao-Di, LENG Yun-Fa, XIAO Yu

2003, 11(1): 66-69.

Abstract(1248) PDF(1507)

Abstract:
This article introduces the concept of farmland GIS and the design of farm land GIS，its five modules，specifications of the functions of the each module，and the prescription map of precision application of fertilizer．

Study on economic benefit analyzing methods for precision agriculture

LU Yao, DING Xian-Zhong, XIE Gao-Di

2003, 11(1): 70-73.

Abstract(807) PDF(1327)

Abstract:
Profitability in the application of variable nitrogen fertilizer rate technology on rice in Shanghai analyzed by partial budgeting method and investment analyzing method respectively shows that buying expensive combine harvester is not profitable by both methods，but RMB 48228 Yuan of annual profit or RMB 278135 Yuan of return(with 24％ IRR)after 10 years will be gained if renting combine harvester．Because more technical data about production need to be collected，the partial budgeting method is more suitable for the implemented projects while the investment analyzing method is suitable for the projects either implemented or not．Further sensitive analysis and national economic analysis which reflects economic．social and environmental effects can be made with it．

Relationship between organic matter content in sandy soil and hydrodynamic parameters

ZHANG Ding-Hua, ZHAI Ming-Pu, JIA Li-Ming, LIN Ping

2003, 11(1): 74-77.

Abstract(1392) PDF(1002)

Abstract:
By testing and analysing saturated water conductivity，water characteristic curve and water constants in sandy soil with different organic matter contents，the relationship between sandy soil organic matter and hydrodynamic parameters is studied．The results show that there are linear relationships between sandy soil organic matter and water parameters：the higher the soil organic matter content，the greater the soil water content under same soil water suction；there is a very remarkable negative linear relationship between the soil saturated water conductivity and the soil organic matter content and < 0.O1 mm physical clay：the soil organic matter is the most important influence factor on soil hydrodynamic parameters in sandy soil．

Effect of magnesium on fertilizer-utilized coefficient of nitrogen， phosphorus and potassium as well as grain yield in maize

YANG Li-Hua, GUO Li-Min, FU Wan-Xin

2003, 11(1): 78-80.

Abstract(1327) PDF(1042)

Abstract:
The application of magnesium (Mg)shows a curved correlativity with the fertilizer-used efficiency of N，P and K．The moderate application of Mg is very conspicuously promotive of maize absorption to N，P，and K．The application of MgO (66．7kg／hm²)in this test，of which the fertilizer utilization coeficient of N，P，and K increases 27．61％，18．03％and 118．73％ respectively than that of the comparison and the yield increases by 6．19％．enhances the contents of protein．1ysine and starch being 3．40％，7．14％，and 17．15％ respectively and reduces the contents of fat and sugar being 2．59％ and 10．86％ respectively．Over fertilizing Mg has a tendency to inhibit the accumulation of N ，P，and K in plant and it is no good for yield．

The characteristics of cluster redpepper in nutrition uptake and its response to N and P fertilizers

SHANG Xing-Jia, WANG Mei-Fang, XING Yong-Hui, CHEN Guo-Sheng, KONG Fan-Hua

2003, 11(1): 81-84.

Abstract(1168) PDF(965)

Abstract:
Fertilizer application study on cluster redpepper was conducted by using saturated-D-optimum design．The average nutrition uptakes of the cluster redpepper are N 274kg/hm² ，P₂O₅57kg／hm² ，K₂O 265kg／hm²，Ca 124kg／hm²，and Mg 26kg/hm² respecitvely when the yidd is 3826kg／hm²．At the yield of 4767．2 kg／hm² ，the highest profit，15131 yuan／hm² ，is obtained．The ratio of output／input is 17．71：1．The optimum application rate of N is 281．1kg／hm² and that of P₂O₅ is 82．1kg／hm² ．

Cycling and balance of zinc in farmland ecosystem of the Jiang-Han Plain in Hubei Province

LIN Kuang-Fei, XU Xiao-Qing, XIANG Ya-Ling, JIN Xia, SHAO Zhi-Hui

2003, 11(1): 85-87.

Abstract(1422) PDF(806)

Abstract:
Two years field experiments with eight cropping systems including wheat-rice， rice-rice，rape-soybean，rape-peanut，wheat-sesame，wheat-cotton，pepper-cabbage，radish-eggplant were carried out to study zinc cycling and balance of farmland ecosystem for Jiang-Han Plain in Hubei Province．The results show that the input way and the amount of zinc in proper order in different type ecosystems are as follows：for vegetable and paddy fields，organic fertilizer>rainfall>natural return>irrigation>seeds(seedlings)and for upland fields，rainfall>organic fertilizer>natural return> irrigation>seeds (seedlings)．The main output of zinc is crop harvest，which ranges from 96％ to 97．6％ with a mean value of 96．7％，while field runoff and soil body leaching are very little．There are more zinc surplus in vegetable and one paddy field because of more organic fertilizer input，two of four upland field has more zinc surplus because of more organic and zinc fertilizer input together，another paddy and the other uplands are deficient in zinc because of less organic and no zinc fertilizer input．

Distribution of available soil nutrients in Duolun County located in the interlaced area of agriculture and pasture and reclaimation measure

LIU Quan-You, TONG Yi-Ping, SUN Jian-Hua, LI Ji-Yun

2003, 11(1): 88-90.

Abstract(1029) PDF(876)

Abstract:
Sixty-one topsoil samples around Duolun County were collected and analyzed．The results show that soil organic matter content averages 3．10g／kg(0．89～13．68g／kg)，alkaline hydrolytic nitrogen 26．6mg／kg(50．1～ 1325．0mg／kg)，Olsen-P 4．89mg／kg (1．0～ 15．0mg／kg)，available potassium 126．0mg／kg，available zinc 0．68mg／kg (0．18～ 4．18mg／kg)，available manganese 12．9mg／kg(2．44～34．57 mg／kg)，water soluble boron 0．49mg／kg(0．12～0．94mg／kg)，and available molybdenum 0．05mg／kg(0．027～0．091mg／kg)．Evaluations according to the above results indicate that 32．7％ of the soil samples are deficient in available N ，58．9％ in P ，19．5％ in K ，88．7％ in Zn，52．7％ in boron，24．3％in Mn．Distribution map of the available soil nutrients are drawn and reclamation measures are recommended also ．

The dynamics of soil nitrate nitrogen leaching and contamination of the groundwater in high-yield farmland

LIU Guang-Dong, WU Wen-Liang

2003, 11(1): 91-93.

Abstract(2765) PDF(1864)

Abstract:
The field scale investigation reveals that in high-yidd farmlands where the managements of the irrigation and fertilization are diferent in Huan tai County of Shandong Province．The dynamics of nitrogen leacNng and the groun dwater pollution quite differ from each other．Soil content of NO₃^--N keeps decreasing after spring and its concentration of NO₃^--N in thegroundwater correspondingly increases gradually．The concentration in the groundwater dramatically changes and reaches the maximum after the raining season，demonstrating that the direct contamination results from the nitrogen fertilization．This is probably related to the more irrigation，lighter soil texture and shallower groundwater in this area．

Mechanism of methane oxidation by methanotrophs and effect of soil moisture content on their activity

DING Wei-Xin, CAI Zu-Cong

2003, 11(1): 94-97.

Abstract(1540) PDF(1668)

Abstract:
The paper reviews the mechanism of methane oxidation by methanotrophs in soils and influence of soil moisture content on methanotrophic function．Four steps are included in the process of methane oxidation in soils．Methane is first oxidized to methanol by sMMO or pMMO and then the latter is further transformed into formaldehyde by methanol dehydrogenase，which is the carbon source of methanotrophic cell syntheses and can be assimilated through RuMP pathway and serine pathway by Type I and Type II methanotrophs，respectively．Type II methanotroph contains both sMMO and pMMO but Type I only pMMO．so Type II methanotroph can survive better in environments where nutrients such as nitrogen，copper are limited．The maximum rate of methane oxidation by methanotroph exists in soil subsurfaces and is mostly influenced by soil moisture content，which is，in turn，mainly dependent on soil texture，soll organic matter and so on．

Advance in the research on the mechanism of degradation of sulfonylurea herbicides in soils

LANG Yin-Hai, JIANG Xin, ZHAO Qi-Guo, HE Wen-Xiang

2003, 11(1): 98-101.

Abstract(1289) PDF(1333)

Abstract:
The sulfonylurea herbicides，an important and new type of herbicides for weed control in agronomic crops，such as rice，wheat and maize，are characterized by high activity low toxicity and low application rates(10～40g／hm²)．When entering the soil，the sulfonylurea herbicides can be degraded by photolysis，alcoholysis，hydrolysis and microbial transformations，and then produce different metabolites．People often select the gas chromatography(GC)，high-performance liquid chromatography(HPLC)，enzyme-linked immunosorbent assay and bioassay to detect the residues of the sulfonylurea herbicides．Standard analytical methods such as HPLC and GC require complicated cleanup procedures to reach the detection limit of 0.1ug／kg，the bioassay and immunoassay procedures are all the rapid，cost-effective and sensitive methods，but are lack of selectivity and specificity．With the research on the model of biodegradation of organic pollutants，the mechanism of degradation of sulfonylurea herbicides in soils is reviewed．

Study on joint toxicity of copper and cadmium to tadpole

YANG Zai-Fu, CHEN Li-Qiao, CHEN Hua-You

2003, 11(1): 102-103.

Abstract(1406) PDF(1391)

Abstract:
The joint toxicity of copper and cadmium to tadpole is studied in acute tests．The results show that the LC₅₀ of Cu²⁺ to tadpole is 0．201 mg／kg，0．138mg／kg and 0．118 mg／kg in 24h，48h and 96h，respecitively；and the LC₅₀ of Cd to tadpole is 32．1 mg／kg，23．3mg／kg and 18．9mg／kg in 24h，48h and 96h，respectively．According to the addictive index method of marking，the addictive index(AI)of Cu²⁺ and Cd²⁺ to tadpole is 1．03，1．12 and 1．20 in 24h，48h and 96h，respectively．The results show synergism action．

Application of allelopathy to weeds contro1

LI Shou-Tian, ZH0U Jian-Min, WANG Huo-Yan, CHEN Xiao-Qin, DU Chang-Wen

2003, 11(1): 104-106.

Abstract(1519) PDF(1930)

Abstract:
Weeds is very harmful to the growth of crops，and the utilization of herbicides will lead to environmental poilution and devdopment of herbicide resistance in weeds．Allelopathy among plants is an effective way to control weeds．Weeds germination and growth are suppressed by allelochemicals released from smothering plants and environmental competition with smothering plants．In addition，the rdease of allelochemicals can be influenced by the measurements of rotation，tillage and other ways，which leads to different levels of weeds suppression．Breeding for smothering plants which posses allelopathic potentials is the most effective way to alleviate or eliminate adverse effects of weeds，which can incorporate allelopathic characteristics into plants to suppress weeds．

Analysis of the unbalanced mechanisms of ecological water environment in the wetlands of forest area in Daxinganling

NA Ping-Shan, ZHANG Ming-Ru, XU Shu-Lin

2003, 11(1): 104-1116.

Abstract(1285) PDF(1051)

Abstract:
The unbalanced mechanisms of ecological water environment of the wetland in Daxinganling forest region are influenced by the enhancement of greenhouse effects and the result of Globle warming，the deforestation of virgin forest and the afforestation on the drainage wetland．The interactional factors will accelerate the surface runoff，enlarge the melting depth of the frozen stagnant water and the melting amount，and increase the surface evaporation．It is the human activities that increase the output of the surface water and the ground runoff from the wetland and its basin to the mountainous valleys and result in the unbalance of ecological water environment in the wetlands．Therefore，the distribution of the virgin forest，the layer of the frozen stagnant water and the wetland in Daxinganling are shrinking to the northern part and the higher elevation．The ecological water environments of forest in Daxinganling are degraded further．

The impacts of acidic deposition on ecoenvironment

WANG Dai-Zhang, JIANG Xin, BIAN Yong-Rong, XU Ren-Kou, HE Ji-Zheng

2003, 11(1): 107-109.

Abstract(1366) PDF(1091)

Abstract:
Anthropogenic emissions of sulfur and nitrogen oxides，mainly from fossil fuel combustion，have led to an increased acidity of aerosol particles and rainy water，then precipitating in industrialized regions and even far away．Symptoms of declined forest，because of its exposure to high concentrations of gaseous pollutants of S0₂ and NO_x，range form foliage yellowing and loss to tree mortality．Cation leaching of soils by acid deposition with subsequent soil acidification and enrichment of the．soil solution with AI have been regarded as the major mechanism leading to forest decline．Nutrient deftciencies have also been thought as the main cause． In sensitive regions receiving acid deposition，waters are often acidic and Al-rich．this makes the lakes and streams serious acidification and fisheries loss．Acid deposition as well as direct effects of gaseous air pollutants cause a widespread damage to aquatic and terrestrial ecosystems and also has an impact on human health．

Characteristic analysis of summer precipitation anomalous types in North China

YOU Feng-Chun, DUAN Ying, SHI Yin-Shan, WANG Hong, WANG Yue-Feng

2003, 11(1): 110-103.

Abstract(1294) PDF(1409)

Abstract:
With EOF，REOF，SSA methods，the anomalous spatial features and main oscillating quasi-periods of summer precipitation in North China are diagnosed and analyzed by using the monthly precipitation date for the period of 1965～2000 from 73 observational stations in North China and near provinces．

Caloric values of plant propagules at Niumulin Nature Reserve Zone of Fujian Province

LIN Yi-Ming, GUO Qi-Rong, LI Zhong-Bao, LIN Peng, GUO Zhi-Jian

2003, 11(1): 117-119.

Abstract(1143) PDF(1132)

Abstract:
The ash contents，gross caloric values and ash-free caloric values in the propagules of 18 plants at Niumulin Nature Reserve Zone of Fujian Province are discussed in this paper． The results show that ash contents in these plant propagules vary from 21.8～77.4g／kg，the average is 46.7g／kg；the plant propagules have the high caloric values，in which gross caloric values and ash-free caloric values vary from 20153.8±50.9J／g to 28533.3±37.2 J／g and from 20900.7J／g to 29552.9 J／g，espectively．Except that gross caloric values and ash-free caloric values of Cyclobalanopsis glauca fruit are both the lowest．High caloric value reflected their functions．

Study on physiological characters of cold resistance of Cycas revoluta

FU Rui-Shu

2003, 11(1): 120-121.

Abstract(1149) PDF(948)

Abstract:
Physiological characters of cold resistance of C．revoluta are studied through artificially simulated cold test．The results show that penetration of protoplasm film and fettered water vary significantly with temperature．There are significant differences on the indexes of cold resistance among C．revoluta with different ages ．As the leaf age increases，the permeability of protoplasm membrane decreases，the sensitive indexes of cold damage for C．revoluta leaf decline，and the bound water and its proportion in total moisture increase，and the cold resistance rises．

Preliminary study on the growth and adaptation of Pinus densiflora var．zhangwuensis

LI Cheng-Xiang, ZHANG Xue-Li, LIU Shu-Ling, LIU Ya-Ping, LEI Ze-Yong

2003, 11(1): 122-123.

Abstract(1199) PDF(1097)

Abstract:
Zhangwu pine(Pinus densiflora var．zhangwuensis)is a natural hybrid of P．densiflora．Studies show that Zhangwu pine has full terminal buds，with high survival in grafting． The diameter and height of 1 and 2-year-old seed-lings are larger than those of P．sylvestris var．mongolica，P．densiflora and P．tablaeformis．The heights of 2-year-old seedlings are 36％，51％ and 33％，respectively，higher than that of the latter thre pines．The 11-year-old tres of Zhangwu pine is significantly larger than those of P ．sylvestris var． mongolica．with 82％ higher in height and 47％bigger in diameter．Zhangwu pine is also resistant to drought and disease，so it is a promising variety for afforestation in the Three-north Region，and worthy of propagation and extension．

The study on high-yield cultivation techniques of Plums

LI Pin-Rong, CHEN Qiang, CHANG En-Fu, ZHOU Hong-Chang, WANG Xi-Quart

2003, 11(1): 124-126.

Abstract(1291) PDF(1223)

Abstract:
Plums have the characteristics of easy planting，fast growth，early blossom and bearing．The research indicates that in the three varieties of Huahong，Jinsha and Prunus salicina，Prunus salicina and Huahong have higher economic value．Rational planting density can improve their yields and production values，while gibberellin can prompt their blossom and bearing．It can be achieved good economic effects to plant Huahong and Prunus salicina in Southeastern Yunnan with 2m×3m of spacing between plant and row，to spray 200mg／kg gibberellin once in blossoming and fruiting periods respectively，and to interplant short-pole crops．

Primary study on Shunde Gingko in Guangdong

LIANG Hong, FENG Ying-Zhu, WANG Ying-Qiang, PAN Wei-Ming

2003, 11(1): 127-129.

Abstract(1315) PDF(1166)

Abstract:
The phenological characters of Gingko in Shunde City of Guangdong Province were observed．An old Gingko tree over 150 years in Qinghui Garden of Shunde City is found to be able to grow，bloom and bear in the place of lower 23°N at an average temperature over 22℃ ．Its phenology including sprouting date．bloom date and seed ripen date is later than that in other area of Guangdong Province．The Gingko tree also shows some specific morphological characters in its seed and biochem ical specifity in its POD ，indicating that this Gingko tree may belong to a new variety.

Environment effect of forest harvesting and protection techniques

QIU Ren-Hui, ZHOU Xin-Nian, YANG Yu-Sheng

2003, 11(1): 130-132.

Abstract(1239) PDF(1234)

Abstract:
This paper gives a comprehensive description of the studies on soil，water properties，regeneration and seedling growth of forest harvesting operation．The current advances in the forest harvesting techniques，machinery and the methods of reducing the impacts on site for forest harvesting are also fully expounded．Finally，the corresponding countermeasures are put forward for the researches on environm ental protection techniques for forest harvesting in China．

Present managing situations and intensive management of man-made forest in China

JIN Zheng-Dao

2003, 11(1): 133-134.

Abstract(1381) PDF(1183)

Abstract:
Man-made forest management is an important component of forest resources cultivation and has important significance to the consolidation of greening achievements，the promotion of the forest quality and productive force of forestland．China’S tree plantation is ranking first in the world in terms of area，however，the management is extensive and the quality is inferior．The paper brings forward four intensive management orientations and developing countermeasures．

The ecological structure and function of the newly built orchard intercropping patterns in the uncultivated sloping field

ZENG Fu-Ping, WANG Ke-Lin, SU Yi-Rong, LI Ling, XIAO Run-Lin

2003, 11(1): 135-138.

Abstract(940) PDF(902)

Abstract:
Ecological structure and function of 5 optimized models in newly built orchard in uncultivated slopping field are analyzed．The results show that organic matter increases by 5％～20％，total N increases by 7％～ 40％．total P increases by 8％～ 70％and total K increases by 15％～ 80％ every year．Good patterns in water and soil retaining are peanut-au-tumn soybean，spring so ybean-autumn soybean， tomato-chinese cabbage， and cayenne-tomato，the soil average erosion module and runoff amount decrease respectively by 44.19％，38.24％，39.52％，37.56％and 22.40％，9.28％，24.11％，and 21.60％ compared with CK．Cayenne-tomato is the highest in biomass，the average yearly is 100280kg／hm²．the second is peanut-autumn soybean，the average yearly is 77030 kg／hm²．Tomato-chinese cabbage is the highest in prod uctivity，the average yearly is 15390 kg／hm²，the second is cayenne-tomato，the average yearly is 13800 kg／hm²．Efficiency of energy introjection in order is cayenne-tomato，peanut-autumn soybean，tomato-chinese cabbage，spring soy-bean-autumn soybean，drought rice-red turnip．The averages of their total energy output／input ratios yearly are 2.96，2.08，2.01，2.O0,and 0.96．

The engineering and techniques to prevent floods and deduce disasters in the gneiss regions of the Taihang Mountains

GUO Su-Ping, ZHANG Jin-Zhu, LI Bao-Guo, YU Zong-Zhou, ZHOU Huai-Jun

2003, 11(1): 139-141.

Abstract(1284) PDF(916)

Abstract:
The engineering and techniques to prevent floods and deduce disasters in gneiss region of hills，low mountain and subalpine were studied．The measures include the combinations of sluice and drainage，biological measure and engineefing measure，and draining systems of slope and gully．These measures conduce to the amounts of water holding in the soil of 3 typical regions that are 320mm，276．4mm and 309．1mm and the amounts of soil erosion that are 38．2t／km²·a，148．6t／km²·a and 44．9t／km²·a，thus decreasing by 89．3％，91．7％ and 77．8％ than the contro1．The effect of preventing floods is very wel1．

Study on the ecological effect of crop residues burned or incorporated in fidd in North Central Irrigated Area of China

WANG Ai-Ling, GAO Wang-Sheng, HONG Chun-Mei

2003, 11(1): 142-144.

Abstract(1128) PDF(1244)

Abstract:
Results from the experiment show that mulching wheat-straw on the soil in summer contributes to preserve soil moisture,1ower soi1 temperature，increase microbe amounts in the surface soi1 and benefits the growth of the maize and the plot yield．Burning crop residues in field can obviously improve the content of available soil nutrients． Mulching wheatstraw on soil surface can inhibit the emergence of weeds，while burning can kill the seeds of weeds．Not all pests increase and diseases become worse because of the incorporation of crop residues．Plot yield with crop residues burned decreases compared to that of crop residues incorporation．

Influence of returning whole corn stalk into soil on wheat growth and its yield

ZHAO Si-Shen, ZHANG Xi-Qun, JIA Su-Mei, DUAN Ru-Hao, WANG Yue-Ying

2003, 11(1): 145-147.

Abstract(1117) PDF(1159)

Abstract:
This paper introduces the techniques of returning whole corn stalk into soil，necessary agricultural machinery，operational technology，and their influence on wheat growth and its yield．The study shows that the rotten rate of corn stalk in one-year rotten period can reach more than 90％．If plough depth is more than 20cm ，95％ of corn stalk can be covered under soil with a depth of about 8cm ．This can guarantee the seeding quality of wheat．The basic seedings and tillers are increased by 23 and 0．2 comparing with traditional way．The dry matter weight and 1000-grain weight by returning whole corn stalk into soil can increase 8．95％and 1．33％．The winter wheat yield can increase 3．81％．

Study on the fallow and intercropping system of Alnus nepalesis on the mountains of Himalayan region

SHEN Li-Xin

2003, 11(1): 148-149.

Abstract(1269) PDF(1060)

Abstract:
Alnus nepalesis intercropping with crops can improve the growth of crops． Traditionally，farmers are used to applying 6000～7500kg fresh leaf of Alnus sp．per hectare as the substitute of livestock fertilizer within the rice plantation because the fertility of 1000kg dry leaves of Alnus sp．equal to 14．3kg nitrogenous fertilizer，2．4kg phosphorus and 2．2kg kalium respectively．This article has described and analyzed the Alnus nepalesis-based mountainous intercropping and fallow system in Himalayan region from the cases of Northeast Indian and Yunnan Province of China．

Countermeasures to harness and develop ecoenvironment in the Junggar Basin

SONG Zong-Shui

2003, 11(1): 150-151.

Abstract(1070) PDF(922)

Abstract:
Ecoenvironmental problems in Junggar Basin mainly are the water resource shortage and secondary silinization of soil．To harness the Junggar Basin in accordance with their special ecoenvironmental problems，some development countermeasures are given such as carrying out the irrigation under film ，protecting and cultivating the desert vegetation，preventing the desert intrude towards the South，governing and developing the Basin reaso nably．

The prospect of organic agriculture in China

ZONG Liang-Gang, LU Dong, YANG Yong-Gang, XIAO Xing-Ji, ZHOU Ze-Jiang

2003, 11(1): 152-154.

Abstract(1504) PDF(1634)

Abstract:
The origin and connotation of organic agriculture，the general situation of organic food in the developed countries，and the present situation and prospect of organic agriculture in China are introduced．The strategic significance of developing organic agriculture and exploiting organic food is summarized also．Finally，some countermeasures are put forward to develop organic agriculture．

Quality characters and improvement tactics of wheat varieties in Hebei Province

WANG Yan-Mei, ZHONG Guan-Chang, LI Jun-Ming, AN Diao-Guo, JI Jun

2003, 11(1): 155-156.

Abstract(1383) PDF(1093)

Abstract:
Through analyzing quality characters of wheat varieties in Hebei Province in recent years，we find that the wheat quality have been greatly improved，but the backward breeding methods and the deficient breeding resource materials seriously limit the high quality-wheat breeding process．The answers to the problem are to improve wheat methods and introduce and create new resources．

Relationships between marsh and precipitation，terrain surface water，ground water in Sanjiang Plain

YIN Xi-Lin, CHU Yu, YANG Wen

2003, 11(1): 157-158.

Abstract(1160) PDF(905)

Abstract:
The paper introduces the location of Sanjiang plain and marsh resources；discusses the relationships between the formation of marsh and precipitation，terrain surface water，groundwater；analyses the influence of marsh development on “ three water”：proves the function of marsh during cycliny changes of“three water”；and advances the important meaning to protect marsh for Sanjiang plain．

Aerobic and thermophilic composting technology of solid organic waste

HUANG Guo-Feng, WU Qi-Tang, WONG J.W .C.

2003, 11(1): 159-161.

Abstract(2684) PDF(2320)

Abstract:
Aerobic and thermophilic compost of solid organic waste is one of the most effective ways for its recycling．The key importance is how to provide a suitable environment for the growth of microbiology during the composting process．The content of moisture，the pH，the C／N value，the aeration rate，and the turning frequency affect the composting progress and eficiency．In this paper，many practical technologies are involved and discussed．

Utilization of eco-nutrition in the production of environmental protection feed

FANG Re-Jun, TANG Shao-Xun

2003, 11(1): 162-164.

Abstract(938) PDF(984)

Abstract:
Based on the reviews of the advanced development of the researches in animal nutrition and feed science for controlling or minimizing animal pollution，the use eficiences of nitrogen，phosphorus，minerals and antibiotic can be increased by the utilization of ideal amino acids patterns，phytase and minerals chelate in feed production．Subsequently the countermeasures of producing environmental protection feed are put forward．

2003 Vol. 11, No. 1