麦田除草剂土壤封闭处理对抗药性杂草的田间防效研究与思考

为了探索不同施药方式和不同类型除草剂对麦田抗药性杂草的防除效果以及对作物的安全性,在小麦播后苗前选用两种除草剂混配进行土壤封闭处理，在返青期根据田间残留草相开展茎叶喷雾处理。结果显示，每667 m²用50%吡氟酰草胺可湿性粉剂20 g+40%砜吡草唑悬浮剂25 mL进行土壤封闭处理，在土壤封闭处理120 d后（小麦茎叶喷雾处理前）调查总草株防效达94.35%。返青期用22%氟吡·双唑酮可分散油悬浮剂50 mL+1%双氟磺草酮·甲基二磺隆可分散油悬浮剂120 mL进行茎叶喷雾处理，对多花黑麦草、婆婆纳等杂草防除效果最好，总草株防效最高可达98.94%，鲜质量防效最高可达99.92%，而且持效性较好。其他各处理总草防效也高，最低株防效87.51%，最低鲜质量防效97.00%，且试验药剂及使用剂量对小麦生长安全。近年来陕西省秋淋的频次加大，多数年份秋播期土壤湿度大，能够满足土壤封闭除草的条件，对出现抗药性的杂草，经试验初步提出“一封一补”的除草策略，即土壤湿度大时，播后苗前选用砜吡草唑+吡氟酰草胺土壤封闭处理，防除绝大部分杂草。小麦返青期再根据田间草相和数量确定是否补防，如果残留杂草数量达不到防治指标，建议不再化学防除，可人工拔除，实现节约成本和农药减施增效目的；如果残留数量达到防治指标，再选用靶标药剂茎叶喷雾补防。补防药剂有甲基二磺隆可防治节节麦，唑啉草酯·双氟磺草胺·氯吡氧乙酸异辛酯、 氟吡·双唑酮+双氟磺草酮·甲基二磺隆、唑草酮·双氟磺草胺、甲基二磺隆+双氟磺草胺+二甲四氯钠异辛酯、辛酰溴苯腈·氯氟吡氧乙酸等均可防治禾本科和阔叶杂草。

Study and Thinking on Control Effect of Soil Sealing Treatment in Herbicide on Weed Resistance to Drugs in wheat Fileld

In order to explore the control effect of different application methods and different types of herbicides on weeds with resistant to drugs in wheat fields and their safety to crops. Two kinds of herbicides were used in soil sealing treatment after sowing of wheat and before seedling, and stems and leaves were sprayed according to the residual grass phase in the field during the period of turning green. The results showed that every 667m² was treated with 20g of 50% diflufenac wettable powder + 25 mL of 40% sulfofenazone suspending agent for soil sealing treatment, and the investigation was carried out after 120 days of soil sealing treatment (before spraying on wheat stems and leaves). The control effect of the total grass plant was 94.35%. In the period of turning green, 50ml of 22% fluopyr·diazolone dispersible oil suspension agent + 120 mL of 1% dispersible oil suspension agent of fensutrazone·methyldisulfuron was used to spray on stems and leaves. Na and other weeds had the best control effect. The total grass plant control effect could reach up to 98.94%, the control effect of fresh quality could reach to 99.92%, and the lasting effect was good. The total grass control effect of other treatments was also high, the lowest plant control effect was 87.51% and the control effect of the lowest fresh quality was 97.00%, and the tested chemicals and dosages were safe for wheat growth. The total grass control effect of other treatments was also high, the lowest plant control effect was 87.51% and the control effect of the lowest fresh quality was 97.00%, and the test chemicals and dosages were safe for wheat growth. In recent years, the frequency of autumn rain in Shaanxi increased, and the soil moisture was high during the sowing period in autumn of the most of years. The weed control measures were worked out. that is, when the soil humidity was high, the soil sealing treatment of fenfenapyr + diflufenacil was used after sowing and before the seedling to control most of the weeds. When the wheat turned green,the measures will be taken according to the grass phase and quantity in the field. If the number of residual weeds did not meet the control target, it was recommended to stop chemical control and remove them manually to save costs and reduce pesticide application and increase efficiency. If the residual amount reached the control target, the target agent was used to spray on the stems and leaves for supplementary control. Methyldisulfuron-methyl as the supplementary control agent can prevent and control A. japonicus. Pinoxaden·dioxsulam·isooctyl chlorpyrifos, flupyridine·bisazolone+dioxsutrazone·methyldimethicone Sulfuron-methyl, fenoxuron, xoxsulam, methyldisulfuron + xoxsulam + dimethyltetrachloride sodium isooctyl ester, capryloyl bromoxynil, chlorofluoropyroxyacetic acid, etc. can control grass and broadleaf weeds.