同期稗草对东北春大豆生长的影响及其经济阈值

Influence of Echinochloa Crusgalli on the Growth of Spring Soybean and its Economic Threshold in Northeast China

稗草是中国北方大豆田的恶性杂草,危害大豆生长发育,降低大豆产量,对大豆生产造成严重威胁。本研究在大田条件下采用添加系列试验和拟合函数关系模型的方法,研究了稗草与大豆的竞争关系。结果表明,在稗草的竞争干扰下,大豆单株荚数,产量均随稗草密度的增加而逐渐降低,而株高没有显著变化。直线函数能较好地拟合大豆产量与稗草密度之间的关系y=-12.863x+2 720.396(R^2=0.982;F=217.340;P=0.001),直线函数亦能较好的拟合大豆产量损失与稗草密度之间的关系y=0.467x+1.017(R^2=0.982;F=217.352;P=0.000 1)。大豆田稗草人工除草的经济阈值为24.65~27.89株·m^(-2),90%乙草胺乳油、12.5%烯禾啶乳油、5%精喹禾灵乳油化学防除稗草的经济阈值分别为2.79~3.39,3.45~4.12和3.18~3.95株·m^(-2)。

Echinochloa crusgalli is a troublesome weed in Northern China and seriously damages soybean growth and reducing soybean yield in soybean fields. A field experiment was carried out to study the effects of E. crusgaUi of different densities （0, 20, 40, 60, 80 and 100 plant.m-z） on the soybean growth and yield by the method of additive series experiment. Resuits showed that increasing density of E. crusgalli significantly reduced soybean＇ s pods per plant and yield. There was no significant impact on soybean plant height. The linear function model was the best in describing the relationship between E. crusgalli density and soybean yield as y = - 12. 863x ＋2 720. 396（R2 =0. 982; F =217. 340; P =0. 001 ） ; while the linear function model as y = 0. 467x ＋ 1. 017 （ Rz = 0. 982 ; F = 217. 352 ; P = 0. 000 1 ） was better for describing the relationship between E. crusgaUi density and yield loss. Economic threshold of E. crusgalli control was 24. 65 -27.89 plants, m^-2 for manual weeding, while for the chemical herbicides of 90% aeetochlor EC, 12. 5% sethoxydim EC, 5% quizalofop-P EC were 2. 79 - 3.39,3.45 - 4. 12 and 3.18 - 3.95 plants· m^-2, respectively.