Abstract: The bio-activity of barnyardgrass, co-toxicity coefficient, compound basis, rice safety, and the effect of weed control in direct-seeded rice field treated with the compound of bensulfuron-methyl and quinclorac were studied. The compounds of bensulfuron-methyl and quinclorac for weed control were more effective compared with bensulfuron-methyl or quindorac individually, especially when the compound rate was 2 percent of bensulfuron-methyl and 34 percent of quinclorac. The six different rates of compounds had no influence on rice plant height, number of tillers or plant fresh weight. When the bensulfuron-methyl and quinclorac were used at the rates of (18+150) g/hm² (in the active ingredient) to (24+198) g/hm², they had a marked effect on controlling the weed density and plant fresh weight for 4 kinds of weeds. The compound of 36% wettable powder applied at 2- to 3- leaf stage in direct-seeded rice field, with the dosages of 162-270 g/hm² was safe to rice. The dosages of 216-432 g/hm² had a remarkable effect on 5 kinds of weeds. When the compound was applied in the direct-seeded paddy, the kinds of weeds controlled were increased and the control effect was improved.

Key words: bensulfuron-methyl, quinclorac, co-toxicity coefficient, compound basis, weed control, herbicide, bio-activity

摘要： 就除草剂苄·二氯（苄嘧磺隆+二氯喹啉酸）对稗草的生物活性、共毒系数、配方依据，对水稻的安全性以及在直播稻田的应用效果进行了试验。结果表明，苄嘧磺隆和二氯喹啉酸复配，比单剂有显著的增效，尤以二氯喹啉酸和苄嘧磺隆在复配剂中的含量分别为34％和2％时增效最为显著。苄·二氯的6个配方对水稻株高、分蘖数和植株鲜质量无不良影响，安全性良好。苄嘧磺隆+二氯喹啉酸（18+150） g/hm2至(24+198) g/hm2对稗草、异型莎草、陌上菜和四叶萍的密度防效和植株鲜质量防效均达到优良水平。36%苄·二氯可湿性粉剂（WP）用于水稻直播田，在水稻2叶1心至3叶期处理，使用剂量162~270 g/hm2(有效成分）对水稻生长无不良影响，安全性好。使用剂量216~432 g/hm2对稗草、水蓼、陌上菜、鸭舌草和丁香蓼的密度防效和植株鲜质量防效均达到了优良水平。与单剂苄嘧磺隆和单剂二氯喹啉酸相比，36%苄·二氯WP的杀草谱提高，杂草整体防效得到改善。

关键词: 苄嘧磺隆, 二氯喹啉酸, 共毒系数, 配方依据, 杂草防治, 除草剂, 生物活性