小飞蓬对油菜产量性状的影响及其经济阈值

Influence of Conyza canadensis on the Yield Character of Oilseed Rape and Its Economic Threshold

采用添加系列试验和模型拟合的方法研究了不同小飞蓬密度下油菜产量性状的变化规律。结果表明,油菜在小飞蓬的竞争干扰下,单株角果数、籽粒数及产量均随其密度的增加而逐渐降低,而千粒重没有显著变化。对数模型可以较好地拟合小飞蓬与油菜角果数(y=-72.543lnx+624.954,P<0.001)、籽粒数(y=-0.935lnx+26.682,P<0.001)、产量(y=-311.994lnx+3167.996,P<0.001)以及产量损失(y=10.838lnx-10.046,P<0.001)间的关系。油菜田进行人工除草时,小飞蓬的经济危害允许水平为7.99%,经济阈值为5.28株/m2。

Additive series experiment and curve fit were adopted to study the change of yield characters of oilseed rape under different density of Conyza canadensis. The results showed that with the interference of Conyza canadensis, the pod number, seed number, yield and yield loss of oilseed rape decreased gradually as the weed density increased, but the 1 000-grain weight showed no significant change. The logarithmic regression model was better for describing the relationship between Conyza canadensis density and rape pod number （y=- 72. 5431nx＋624. 954, P〈0. 001）, seed number （y=-0. 9351nx＋26. 682,P〈0. 001）, yield （y=-311. 9941nx＋3 167. 996,P〈0. 001） and yield loss （y=10. 8381nx-10. 046,P〈0. 001）. When manual weeding was adopted for the control of Conyza canadensis in oilseed rape fields, the economic infestation level for Conyza canadensis was 7. 99% and the economic threshold was about 5, 28 plant per m^2.