Studies On Eco-economic Index Of Weeds Control In Summer Maize Field In Shandong Province

The experiment was conducted using fild and pot method in 2002 and2003 in summer maize field of Dezhou City. The experiment build themathematic modle for maize yield loss rate and the weeds populationdensity, dry weight. At the same time, build the mathematic modle forcomparative maize yield and the interferential time of weeds and bourgeontime of weeds. The results were as follows: The relation of summer maize yield loss rate and weeds populationdensity 1.1 The mathematic modle of summer maize yield loss rate(Y, %)andredroot amaranth population density(X, plants·m-2) Y =121.9885·e(-15.4517/x) The Eco-economic threshold value mathematic modle of redrootamaranth (100C + EF)*100 X = -15.4517/ln 121.9885PVE Eco-economic threshold value of redroot amaranth: 4.36 plants·m-2 1.2 The mathematic modle of summer maize yield loss rate(Y, %) andGoosegrass population density(X, plants·m-2) Y =0.443815·X1.1187 The Eco-economic threshold value mathematic modle of Goosegrass (100C + EF)*100 X =( )1/1.1187 0.443815PVE Eco-economic threshold value of Goosegrass: 6.37 plants·m-2 1.3 The mathematic modle of summer maize yield loss rate(Y, %)andweeds population density(X, plants·m-2) 4山东农业大学硕士学位论文 Y =68.8304·e(-39.8705/x) The Eco-economic threshold value mathematic modle of weeds: X =? 39.8705/ ln (100C + EF)*100 68.8304PVE Eco-economic threshold value ofweeds: 13.42 plants·m-2 2 The relation of summer maize yield loss rate and weeds fresh weight 2.1 The mathematic modle of summer maize yield loss rate(Y, %) andredroot amaranth fresh weight(g, plants·m-2) Y=(1.2477+0.04961x)0.731766 The Eco-economic threshold value mathematic modle of redrootamaranth 0.731766(100C+EF )*100₁.2477 X= PVE 0.04961 Eco-economic threshold value of redroot amaranth: 87.73 g ·m-2 2.2 The mathematic modle of summer maize yield loss rate(Y ,%)andGoosegrass fresh weight(g, plants·m-2) Y=(-542.6676+9.5341x)0.380071 The Eco-economic threshold damage value mathematic modle ofGoosegrass: 0.380071(100C+EF )*100+542.6676 X= PVE 9.5341 Eco-economic threshold damage value of Goosegrass: 59.81 g·m-2 2.3 The mathematic modle of summer maize yield loss rate(Y, %)andweeds fresh weight(X, g·m-2) Y=(-5156.6276+53.8461x)0.359575 The Eco-economic threshold damage value mathematic modle ofweeds: 5郑光辉:山东省夏玉米田杂草生态经济指标的研究 0.359575(100C+EF )*100+5156.6276 X= PVE 53.8461 Eco-economic threshold damage value of weeds: 96.38g·m–2. 3 The relation of summer maize yield loss rate and interferential timeof weed 3.1 The mathematic modle of summer maize yield loss rate(Yu) andnterferential time of redroot amaranth (Xu) Yu=100.4189*(1-e[-((x-0.017834)/54.0745)-0.818052]) The relation of summer maize yield loss rate(Yd)and the time ofredroot amaranth bourgeon(Xd): Yd=103.6243/(1+e(0.266348-0.04196x)) The control time thresholds of redroot amaranth were 11.61 to 66.79days after summer maize emerged. 3.2 The mathematic modle of summer maize yield loss rate(Yu) andnterferential time of Goosegrass(Xu): Yu=103.0463*(1-e[-((x-0.001081)/99.3592)-0.573969]) The relation of summer maize yield loss rate (Yd)and the time ofGoosegrass bourgeon(Xd) Yd=100.0872*(1-e[-((x+137930.0404)/137922.5199)3062.1050]) The control time thresholds of Goosegrass were 15.36 to 46.21 daysafter summer maize emerged. 3.3 The mathematic modle of summer maize yield loss rate(Yu)andnterferential time of weeds(Xu): Yu=100.4822*(1-e[-((x-0.004188)/63.4141)-0.682829]) The relation of summer maize yield loss rate (Yd) and the time ofweeds bourgeon(Xd):...