In recent years,the ecological quality of ditches became worse and worse with the degradation of its ecological functioning.It was necessary to apply a multi-disciplinary and multi-scale approach to study ditches base...In recent years,the ecological quality of ditches became worse and worse with the degradation of its ecological functioning.It was necessary to apply a multi-disciplinary and multi-scale approach to study ditches based on landscape ecology theory.Spatial and network features of agricultural ditches in Lake Dianchi Basin were analyzed by geographic information system technology.The results indicated that the ditches at high level were made by concrete or block stones,the coverage of vegetation of buffer zones and width ratio between ditch sections and vegetation zones were very low;The network of agricultural ditches in Lake Dianchi basin had similar characteristics,the connectivity and circuitry were low,and the fractal dimension index of ditch network were larger in southeastern and southern banks.展开更多
[Objective] The aim of this study was to reveal and analyze the spatial distribution pattern of thrip（Odentot hrips lati） on alfalfa（Medicago sativa）.[Method] Within alfalfa plantation areas,experimental plots wit...[Objective] The aim of this study was to reveal and analyze the spatial distribution pattern of thrip（Odentot hrips lati） on alfalfa（Medicago sativa）.[Method] Within alfalfa plantation areas,experimental plots with the sizes of 10×10,10×20,10×30,20×30,20×40,20×80,30×30,30×40,30×50,40×40,40×50,40×80 and 50×50 m2 respectively were set up in the randomly selected sampling sites of 1 m ×2 m in size.During bud-emerging period and florescence period of alfalfa in the experimental plots,the number of thrips was counted and their distribution pattern was measured using XU Ru-mei＇s method.[Result] During bud-emerging period of alfalfa,the spatial distribution of thrips assumed an elliptic shape sized of 40×30-40×40 cm2 at horizontal level and that presented an ascending-falling trend of tress density down from the top at vertical level.During the florescence period of alfalfa,it showed a homogeneous distribution or randomly distributed pattern at horizontal level and a falling trend of tress density from the top to the apex to the root at vertical level.[Conclusion] Our results provide theoretical basis for field selection of insect-resistant alfalfa varieties.展开更多
基金Supported by National Key Sciences and Technology Program for Water Solutions (2008ZX07102-004) ~~
文摘In recent years,the ecological quality of ditches became worse and worse with the degradation of its ecological functioning.It was necessary to apply a multi-disciplinary and multi-scale approach to study ditches based on landscape ecology theory.Spatial and network features of agricultural ditches in Lake Dianchi Basin were analyzed by geographic information system technology.The results indicated that the ditches at high level were made by concrete or block stones,the coverage of vegetation of buffer zones and width ratio between ditch sections and vegetation zones were very low;The network of agricultural ditches in Lake Dianchi basin had similar characteristics,the connectivity and circuitry were low,and the fractal dimension index of ditch network were larger in southeastern and southern banks.
基金Supported by Natural Science Foundation of Guizhou Province(J[2010]2248)~~
文摘[Objective] The aim of this study was to reveal and analyze the spatial distribution pattern of thrip（Odentot hrips lati） on alfalfa（Medicago sativa）.[Method] Within alfalfa plantation areas,experimental plots with the sizes of 10×10,10×20,10×30,20×30,20×40,20×80,30×30,30×40,30×50,40×40,40×50,40×80 and 50×50 m2 respectively were set up in the randomly selected sampling sites of 1 m ×2 m in size.During bud-emerging period and florescence period of alfalfa in the experimental plots,the number of thrips was counted and their distribution pattern was measured using XU Ru-mei＇s method.[Result] During bud-emerging period of alfalfa,the spatial distribution of thrips assumed an elliptic shape sized of 40×30-40×40 cm2 at horizontal level and that presented an ascending-falling trend of tress density down from the top at vertical level.During the florescence period of alfalfa,it showed a homogeneous distribution or randomly distributed pattern at horizontal level and a falling trend of tress density from the top to the apex to the root at vertical level.[Conclusion] Our results provide theoretical basis for field selection of insect-resistant alfalfa varieties.
