几种封闭除草剂两个时期用药效果对比及其交互作用分析

Comparison of weed management with several pre-emergence herbicides under two application periods and analysis their interactions in weed control

通过田间小区试验评价了前期筛选的几种适用“播喷同步”的封闭除草剂对水稻的安全性及对直播田杂草的防效,明确了“播喷同步”技术与常规播后4 d封闭的差异,以及施药时期×除草剂种类交互作用及对控草效果的影响,优化水稻直播田杂草防控策略。试验结果表明,播种当天(播喷同步)或播种后4 d(常规方法)喷施120 g/L噁草酮EC 360 g/hm^(2)+10%苄嘧磺隆WP 30 g/hm^(2)(有效剂量,下同)、33%嗪吡嘧磺隆WG 74.25 g/hm^(2)+300 g/L丙草胺EC 450 g/hm^(2)、60%丁草胺EC 1 350 g/hm^(2)+10%吡嘧磺隆WP 30 g/hm^(2)、35%吡嘧·嘧草·丙OD 525 g/hm^(2)、300 g/L丙草胺EC 450 g/hm^(2)+10%苄嘧磺隆WP 30 g/hm^(2),5组除草剂处理对直播稻均无可见药害,各“播喷同步”处理的杂草防除效果不低于常规播后4 d用药;同步喷施33%嗪吡嘧磺隆WG+300 g/L丙草胺EC防效最高,药后35 d对禾本科、莎草科、阔叶草防效达到98.3%及以上;水稻直播4 d后喷药,水稻成苗率提高但35 d的禾本科杂草防效低,33%嗪吡嘧磺隆WG+300 g/L丙草胺EC处理受喷药时间影响小;复合双因子方差分析表明,单一因子会对水稻安全性、杂草防效产生显著影响,用药时期×除草剂种类交互对水稻安全性无显著影响,对控草效果影响显著。因此,直播田封闭除草剂宜尽早施药提高防治效果,同时应选用安全高效的除草剂,33%嗪吡嘧磺隆WG+300 g/L丙草胺EC处理,可于播种当天到播种后4 d内用药,保障直播田杂草防治效果的同时兼顾水稻安全。

Rice safety and weed control efficacies with several pre-emergence herbicides,which were preliminary screened basing on “seeding spray synchronous technology”(ST),were evaluated in direct rice seeding field(DRS).Difference of impacts on weed control under two application periods of ST and four days after sowing(conventional treatment,CT) were analyzed,effects of herbicides×application periods and their interaction were investigated,and weed control strategy in DRS were optimized.Field plot experiment showed that rice were safe when being sprayed with five compound herbicides of 360 g/hm^(2)oxadiazon 120 g/L EC(active ingredient,the same below)+30 g/hm^(2)bensulfuron-methyl 10% WP,74.25 g/hm^(2)metazosulfuron 33% WG+450 g/hm^(2)pretilachlor 300 g/L EC,1 350 g/hm^(2)butachlor 60% EC+30 g/hm^(2)pyrazosulfuron-ethyl 10% WP,525 g/hm^(2)pyrazosulfuron-ethyl·pyriminobac-methyl·pretilachlor 35% OD,450 g/hm^(2)pretilachlor 300 g/L EC+30 g/hm^(2)bensulfuron methyl 10% WP,and the weed control efficacy was higher with ST than that of CT.The treatment of metazosulfuron 33% WG+pretilachlor 300 g/L EC under ST had the highest effect in controlling Gramineae,Cyperaceae and broad-leaved grass,with the efficacy of more than 98.3% 35 days after application.Moreover,compared with ST,the rice seedling rate was enhanced under CT,but control efficacy against gramineous weed was decreased 35 days after application.However,application time had less effect on control efficacy of metazosulfuron 33% WG+pretilachlor 300 g/L EC treatment.Compound two-way ANOVA showed that single factor had significant impact on rice safety and weed control efficacy,and two factors interaction had no effect on rice safety but had significant effect on weed control.Therefore,we should select the safe and effective pre-emergence herbicides and apply early to improve the weed management in DRS.Moreover,for the herbicides of metazosulfuron 33% WG+pretilachlor 300 g/L EC,they should be applied during 0-4 d after sowing to ensure the weed control efficacy and rice safety.