Eco-economic Threshold and Critical Control Period of Weed Interference in Maize Fields

摘要

To investigate the eco-economic thresholds of weeds and the critical period for their control,combining economic and ecological perspectives to achieve scientific weed management,four dominant weeds,Echinochloa crus-galli（L.） P.Beauv,Chenopodium album L.,Digitaria sanguinalis（L.） Scop,and Commelina communis L.,were selected as experimental subjects,based on their common occurrence in spring maize planting areas in Northern China.A predictive model for maize yield loss caused by mixed weed populations was established.The study analyzed the eco-economic thresholds of weeds under different control measures and determined the optimal period for weed control by combining the critical control period.A logarithmic function model was developed to describe the relationship between mixed weed density and maize yield loss:y=5.98751n（x）-6.5407（R²=0.949,F=131.244,P=0.000）.The optimal model for the critical period of competition between weeds and maize in maize fields was:y=-0.0027x²+0.5624x-10.064（R²=0.968,F=30.513,P=0.032）.When the weed density in maize fields reached 5.57 plants·m^-2,manual weeding should be conducted promptly.When the weed density was 3.41 plants·m^-2 or 3.48 plants·m^-2,soil or foliar treatments should be applied,respectively.If the weed density reached 3.93 plants·m^-2,a combination of soil and foliar treatment should be implemented.The critical period for manual weeding was 28.4 days after sowing,for soil treatment it was 19.9 days,for foliar treatment it was 21.8 days,and for the combined treatment of soil and foliar methods,it was 23.5 days after sowing.Retaining weeds for up to 15 days after maize sowing did not result in a yield loss and could even have a positive effect on maize yield.

关键词

Echinochloa crus-galli(L.) P.Beauv / Digitaria sanguinalis(L.) Scop / Chenopodium album L. / Commelina communis L. / eco-economic threshold / critical period