野燕麦、遏兰菜复合群体对小麦产量损失研究

EFFECT OF THE POPULATION COMPLEX OF WILD OATS AND BASTARD CRESS ON WHEAT YIELD

试验采用二因素五水平二次回归通用旋转组合设计,研究野燕麦(Avena fatua)(x_1)、遏兰菜(Thlaspi arvense)(x_2)不同密度的复合群体与小麦减产率((?) y)、穗数减少率((?)s)、穗粒数减少率((?)g)等指标函数间的变化规律。结果表明,野燕麦密度是影响产量的主要因子,遏兰菜密度是次要因子。野燕麦、遏兰菜密度与小麦减产率、穗数减少率、穗粒数减少率在试验范围内呈正相关关系;小麦减产率回归方程为:(?)y=20.70+6.0913x_1+3.1563x_2+4.3250x_1 x_2-2.1355x_1~2+0.7995x_2~2野燕麦和遏兰菜种群,每 m^2在7.7株和5株、7.7株和26.3株、35.7株和5株时,不造成小麦穗数减少,可不进行化学防除;在野燕麦每 m^2超过35.7株和遏兰菜超过26.3株的复合群体,需要做好防除工作。

The design of the all-purpose rotatable quadratic regression was usedin this experiment.The densities of wild oats,Avena fatua L.,(x_1)and bastard cress,Thlaspi arvense L.,(x_2)were fixed at 5 levels andcoded respectively to study their effects on the percent losses of wheatyields((?)y),spikes((?)s)and grains per spike((?)g).The results indi-cated that x_1 was the major factor to cause wheat yield damage and x_2was the second.In the extent tested,positive correlations were ob-served between all the Y and x,and the equation of percent loss of wheatyields was (?)_y=20.70+6.0913x_1+3.1563x_2+4.325x_1x_2-2.1355x_1~2+0.7995x_2~2.Chemical control of these 2 weeds is not necessary when actual densitiesof the population complex of wild oats and bastard cress are under 7.7and 5,7.7 and 26.3,or 35.7 and 5 plants m^(-2) because of no significantspike losses,but necessary when they exceed 35.7 and 26.3 plants m^(-2).