油菜田遏蓝菜发生规律与化学防除

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

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。

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.