移栽油菜田杂草防除临界期初步研究

油菜移栽后不同时间除草的试验表明,油菜移栽后的有草天数与油菜籽产量损失率之间是logistic曲线关系。曲线的两个拐点为t1=39.7d,t2=92.3d。在t1之后和t2之前,损失率增长迅速。因此,t1=39.7d可作为杂草与油菜的竞争临界期。应用时,可掌握为油菜移栽后40～45d。因此,油菜田除草应掌握在油菜移栽后45d之前。

Preliminary studies on the critical control stage of weeds in transplanting oilseed fields

The result of the test of controlling oilseed field weeds at different time after transplanting showed that there is logistic curve relationship between the days of weeds keeping in the field and the loss of oilseed. In the curve, the two turn value are t1=39.7d and t2=92.3d. And between t1 and t2, the loss ration increase quickly, suggesting that t1 should be regarded as the challenge critical stage between weeds and oilseed in 40 to 50 days after transplanting. Based on the result, weeds should be controlled in 45 days after transplanting.