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为了明确杂草种类对杂草密度与夏玉米产量损失之间的函数关系的影响及反枝苋和马齿苋为害夏玉米的产量损失模型,在田间开展了此项研究。试验结果表明,反枝苋和马齿苋为害均不显著地影响夏玉米的籽粒重和单位面积穗数,造成夏玉米产量损失主要是通过降低每穗的籽粒数来实现的。杂草密度和夏玉米产量损失之间的函数关系因杂草种类不同而异,描述反枝苋密度和夏玉米产量损失之间的关系用双曲线优于S形曲线,而描述马齿苋密度和夏玉米产量损失之间的关系则用S形曲线优于双曲线。在北京地区,反枝苋和马齿苋密度(X)与夏玉米产量损失(Y_L)的模型分别为:Y_L=0.49X/(1+0.49X/58.73)和Y_L=18.36/(1+1601.83X~(-1.6))
In order to clarify the effect of weed species on the relationship between weed density and yield loss of summer maize and yield loss model of summer maize damaged by Amaranthus retroflexus and purslane, this study was conducted in the field. The results showed that both Amaranthus retroflexus and Purslane had no significant effect on the kernel weight and spike per unit area of summer maize, which resulted in the loss of maize yield by decreasing the number of grains per panicle. The relationship between the weed density and summer maize yield loss varies according to the weed species, describing the relationship between Amaranthus retroflexus density and summer maize yield loss as better than the S-shaped curve by hyperbola, The relationship between yield loss and summer maize is better than the hyperbola with sigmoidal curve. In Beijing, the models of density (X) and yield loss (Y_L) of Amaranthus retroflexus and Portulaca oleracea were Y_L = 0.49X / (1 + 0.49X / 58.73) and Y_L = 18.36 / (1 + 1601.83 X ~ (-1.6))