eco-economic threshold 第1页

STUDY ON THE ASCENDENT CRABGRASS‘‘ ECO-ECONOMIC THRESHOLD MODEL AND ECO-ECONOMIC CONTROL THRESHOLD MODEL IN SUMMER GROUNDNUT FIELD STUDY ON THE ECO-ECONOMIC THRESHOLD PERIOD FOR CONTROLLING DIGIT ARIA SANGVINALIS IN SUMMER MAIZE FIELD IN NORTH CHINA Eco-Economic Threshold Period for Controlling Weeds in Summer Maize Field of Huang-Huai-Hai Region