豚草对花生产量性状的影响及其经济阈值

为明确豚草( Ambrosia artemisiifolia )对花生生长和产量的影响及其经济阈值，采用添加系列试验和拟合函数关系模型的方法，研究了豚草与花生的竞争关系。结果表明，在豚草竞争干扰下，花生单株分枝数、荚果数、有效荚果数及产量均随豚草密度的增加而逐渐降低，而株高没有显著变化。指数模型能较好地拟合豚草对花生分枝数（y=7.307e-0.003x，P<0.001）的影响；对数函数模型能较好地拟合豚草密度与花生单株荚果数(y= -2.355lnx +16.325，P<0.001)、有效荚果数（y= -38.104㏑x+248.022，P<0.001）、花生产量（y= -1 172.945lnx+6 765.501，P<0.001）以及产量损失（y = 17.825lnx-2.866，P<0.001）间的关系。花生田豚草人工拔除的经济阈值为1.42株/m2，使用50%乙草胺乳油防除的经济阈值为1.22株/m2。

Infiuence of common ragweed (Ambrosia artemisiifolia) on peanut yield and economic threshold

Additive series experiment and regression fitting methods were used to study the influence of invasive species A.artemisiifolia on peanut(Arachis hypogaea) growth and yield in field.Results showed that increasing density of A.artemisiifolia significantly reduced peanut’s branch number,pod number,effective pod number and yield.There was no significant impact on peanut plant height.Exponential regression model was the best in describing the relationship between A.artemisiifolia density and peanut branch number as y=7.307e-0.003x,P<0.001;while logarithmic regression model was better in describing the relationship between A.artemisiifolia density and peanut effective pod number(y=-38.104lnx+248.022,P<0.001),yield(y=-1 172.945 lnx+6 765.501,P<0.001),and yield loss(y=17.825 lnx-2.866,P<0.001).Economic threshold of A.artemisiifolia control was 1.42 plants per square meter for manual weeding and 1.21plants per square meter for acetochlor control.