Effect of Echinochloa crusgalli and Abutilon theophrasti on Growth and Development of Spring Maize and Economic Threshold of Different Weeding Method
In order to optimize the weeding strategy and reduce the stewardship and production cost,experiment was carried out in maize fields of Liaoning Province in 2021.In the field,Echinochloa crusgalli and Abutilon theophrasti grew together according to different density ratios with 17∶0,29∶0,30∶3,43∶3,97∶4,262∶5,792∶10,0∶10 and 719∶0,and E.crusgalli and A.theophrasti free check(CK)was also designed.We analysised the change of indexes of growth and development and yield attributes of maize,constructed the power function model between density ratio of E.crusgalli and A.theophrasti and yield of maize,and then drived economic thresholds of different weeding method to explore competitive relationships between these two weeds and maize.The results showed that comprehensive competing interference of these two weeds had no significant effect on plant height at pollination period and stem diameter at harvest period.While density ratios of E.crusgalli was highest,the comprehensive competing interference had significant effect on stem diameter at pollination period and plant height and fresh weight at harvest period,but had no effect on ear length,ear diameter,single ear weight and 100-seed weight of maize.Meanwhile,yield of maize was highest.The power function model was y=16 015.94x-0 047(r2=0.993,F=11 651.090,P=0.000 1),which could better fit the relationship between density ratio of these two weeds and yield of spring maize in Liaoning.The principle of weeding at emergence stage should be followed in weed control.Different weeding methods should be implemented according to their corresponding economic thresholds to minimize the loss of maize yield when controlling these two weeds grew together in maize fields.Economic threshold of artificial weeding was 8.75 plants/m2;Economic thresholds of weeding via acetochlor·atrazine·2,4-D-ethylhexyl and mesotrione·nicosulfuron·atrazine were 4.45,4.58 plants/m2;And economic threshold of weeding via acetochlor·atrazine·2,4-D-ethylhexyl mixed with mesotrione·nicosulfuron·atrazine was 5.40 plants/m2.
spring maizeEchinochloa crusgalliAbutilon theophrastidensity ratio of weeds grew togetheryieldeconomic thresholdcontrol index
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