土壤处理防治小麦田杂草节节麦药剂筛选

Screening of pre-emergence herbicides to control a noxious weed Aegilops tauschii in wheat fields

节节麦是我国冬小麦田中的一种恶性杂草。本文通过室内生物测定和田间药效试验筛选了有效防治节节麦的土壤处理剂,为冬小麦田节节麦的化学防治提供理论依据。温室试验结果发现:氟噻草胺、噁草酮和异丙隆对节节麦毒力较高,GR50值分别为37.2、15.7和349.3 g/hm^(2),均低于各自田间推荐剂量,但其在小麦与节节麦之间的选择性指数为0.6~1.1(<2),说明安全性差。异丙隆与噁草酮按不同质量比复配后,对节节麦联合作用类型均呈现加成作用,其中以质量比4:1复配后的除草活性高于异丙隆单剂,且各单剂对小麦的安全性有所提高,选择性指数达2.0。田间药效试验结果显示:异丙隆与噁草酮复配后在有效成分600~900 g/hm^(2)剂量下于杂草出苗前进行土壤喷雾处理,药后60 d对雀麦、节节麦、猪殃殃和播娘蒿的防除效果达86%以上,增产效果明显,达13%以上,且对小麦安全。

Aegilops tauschii,a noxious weed,is widely distributed in winter wheat fields in China.The feasibility of pre-emergence(PRE)chemical control of A.tauschii was studied by the greenhouse and field experiments to find out appropriate PRE herbicides against A.tauschii and provide theoretical foundation for the chemical control of A.tauschii.The results of greenhouse study showed that flufenacet,oxadiazon and isoproturon were effective against A.tauschii,with GR50 values of 37.2,15.7 and 349.3 g/hm^(2),respectively,which were all below their field recommended rates.However,their selectivity indexes(Is)were below 2(0.6-1.1),which suggested poor safety to wheat.The joint effect type was additive when isoproturon was mixed with oxadiazon for the control of A.tauschii.When the mass ratio was 4:1(isoproturon:oxadiazon),the weed control efficacy of the mixtures against A.tauschii was higher than that of isoproturon applied alone,and the safety of the mixtures to tested wheat cultivars was improved when compared with that of oxadiazon or isoproturon used alone with Is of 2.0.The results of the field experiments showed that the PRE application of the mixtures of isoproturon and oxadiazon at 600-900 g/hm^(2) had 86%efficacy against Bromus japonicus,A.tauschii,Galium aparine and Descurainia sophia at least,increased wheat grain yield by at least 13%,and were safe to the test cultivar of winter wheat.