为了探究450 g/L二甲戊灵微囊悬浮剂在直播水稻田的应用潜力，采用室内生物活性测定的方法，对450 g/L二甲戊灵微囊悬浮剂对直播水稻的生物安全性以及对稗草和鳢肠的防效进行研究。结果表明：在水稻播后苗前，当450 g/L二甲戊灵微囊悬浮剂用量为1085~1294 g(a.i)/hm2时，能够有效的防除稗草和鳢肠，而对水稻的出苗率、叶色、株高和地上部鲜重等无明显影响；施药处理后，不能直接灌水，应采用底部渗水的方式保持苗床湿润，则450 g/L二甲戊灵微囊悬浮剂对水稻的安全性明显好于用同样方法使用的50%丁草胺乳油。为450 g/L二甲戊灵微囊悬浮剂在直播稻田的推广应用提供理论依据。

The objective of this study was to evaluate the effect of pendimethalin 450 g/L CS on barnyardgrass and Eclipta prostrate in the direct seeding rice field. The rice safety and control efficacy of barnyardgrass and Eclipta prostrate with pendimethalin 450 g/L CS was researched in direct seeding rice field. The results indicated that barnyardgrass and Eclipta prostrate were controlled effectively with the pre-emergence application of pendimethalin 450 g/L CS (the effective application 1085-1294 g/hm2), but the seedling emergence, leaf color, plant height and shoot fresh weight of rice was not affect in greenhouse. The rice safety with pendimethalin 450 g/L CS is much better than butachlor 50% EC after treatment by keeping the seedbed moist, but not be irrigation directly. The effect of pendimethalin 450 g/L CS on barnyardgrass and Eclipta prostrate were studied in the direct seeding rice field to provide the theoretical basis.