关中硬茬直播夏玉米田杂草发生规律及化学防除研究

Study on the Occurrence Regularity and Chemical Control in No-tillage Summer Planting Maize Field in Guanzhong Area

采用倒置"W"九点取样法,对陕西关中10个县区40个乡镇120块硬茬直播夏玉米田杂草定点取样调查。结果表明,关中硬茬直播夏玉米田杂草种类主要有12科21属22种。根据杂草的分布特点,将关中硬茬直播夏玉米区划分为4个杂草区域,各区域杂草的出苗状况一致,玉米播种后6d,各种杂草陆续出土,6~24d为杂草的发生高峰期,至播种后30d(玉米3~4叶期)时出土杂草已占玉米全生育期杂草总数的93%以上。以硝磺草酮、莠去津和烟嘧磺隆为试材,分别在夏玉米生长的3~4叶期、5~6叶期和8~9叶期用药,结果显示,相同剂量同一药剂处理在玉米生长的不同时期喷雾,其防效大小存在显著性差异,3~4叶期用药综合效果最佳。烟嘧磺隆安全性试验证实,夏玉米3~4叶期用药最为安全。

Weeds survey was conducted with inverted W-pattern sampling methods at 120 plots in notillage field of 40 towns in 10 counties in Guanzhong area.The results showed that 22 weed species belonging to 21 genera and 12 families were founded.Four different weed areas were divided in field of summer planting maize in Guanzhong area according to the distribution characteristics of the weeds.Weeds emergence was the same in the four weed areas in Guanzhong.Various weeds occurred in succession 6 days after maize planted.Weed emergence peak appeared from the sixth day to twentyfourth after maize planted.More than 93% accounting for of the total number of weeds in the whole stages occurred within 30 days after maize planted（at 3-4 leaf stage of maize）.Spraying mesotrione,atrazine and nicosulfuron in the maize 3-4 leaf stage,5-6 leaf stage and 8-9 leaf stage respectively,significant different effects were obtained.The effects for 3-4 leaf stage was the best.The safety testing of nicosulfuron showed that was the optimal time for safty using nicosulfuron to control weeds in the maize field.