油菜田遏蓝菜发生规律与化学防除

试验明确,青海湟中地区遏蓝菜全生育期约为115d,出苗高峰期为5月上旬至中旬。种子发芽出苗最适土壤深度为1.0～3.0cm。花期约34d,果期约20d,单株结籽量平均690粒。种子有休眠习性,室外埋入土层8d萌发率为1.5％。遏蓝菜与油菜竞争危害表现在油菜全生育期,植株含氮、磷、钾量比油菜高2.3％～225.0％。遏蓝菜发生量与油菜籽产量呈极显著负相关关系,回归方程为y=203.15-0.53x。采用3种除草剂及其混剂对遏蓝菜的防除效果均在90％以上,油菜籽增产显著。

Occurrence of Thlaspi arvense L. in rape seed fields and its chemical control

In the Huangzhong Areas of Qinghai, the growth period of Thlaspi arvense L. lasted around 115 days, the e-mergence period about 87 days, and the emergence peak was in early to middle May. The best soil depth for emergence was 1.0-3.0 cm. The flowering period lasted about 34 days, fruting period about 20 days, and overage seeds per single plant were 690 grains. There was a seed dormancy. The emergency rate was 1.5% after planting at the depth of 8cm in soil. There was a strong competition of Thlaspi arvense with spring rape seeds during the whole growth periods. The contents of N, P, K of T. arvense were higher by 2. 3 % - 225.0 % than those of spring rape seeds. There was a significant negative correlation between T. arvense and the yields of spring rape seeds. The regression equation was y - 203. 15 -0.53 x. The control efficaey was above 90 % by applying 3 kinds of herbicides and their mixtures which increased rape seeds significantly.