精喹禾灵对魔芋园土壤生态及魔芋安全性评价

Effects of quizalofop-P-ethyl on soil ecology and konjac safety

[目的]明确精喹禾灵使用后对魔芋园土壤生态系统的毒理效应及对魔芋安全性的影响,筛选小宗作物魔芋的适用除草剂。[方法]测定精喹禾灵使用后魔芋根际土壤微生物生物量、土壤酶活性及其在魔芋和杂草间的选择性指数。[结果]在高于56.25 g a.i./hm2剂量处理下,精喹禾灵对土壤细菌和放线菌具有显著的抑制作用(P<0.05),而各剂量处理对真菌没有影响。不同剂量处理后,精喹禾灵对土壤蔗糖酶、酸性磷酸酶表现出先抑制后恢复的过程;低剂量精喹禾灵对土壤脲酶表现为激活作用,高剂量处理则表现出抑制作用;各剂量处理对过氧化氢酶表现为激活作用,随后逐渐恢复正常。精喹禾灵在魔芋和杂草间的选择性指数>5,对魔芋安全。[结论]精喹禾灵在≤56.25 g a.i./hm2剂量应用时,对魔芋园土壤生态及魔芋作物未表现出显著的毒理风险,可以安全应用。

[Aims]The study aims to evaluate the toxicological effects of quizalofop-P-ethyl on the soil ecosystem and the safety to konjac,and to screen out herbicides in konjac field.[Methods]The soil microorganism biomass,soil enzyme activity and the selectivity index between konjac and weeds were investigated after using quizalofop-P-ethyl.[Results]The results showed that the activities of soil bacteria and actinomycetes declined significantly at the doses of higher than 56.25 g a.i./ha(P<0.05),and there was no significant change on fungi after treatment of quizalofop-P-ethyl.After treated with different concentration,soil invertase and acid phosphatase were inhibited firstly,and then recovered.Quizalop-P-ethyl active soil urease when applied at low dosage,while inhibit soil urease at hith dosage.Moreover,catalase was activated with quizalofop-P-ethyl treatment,and then returned to normal.The selectivity index of quizalofop between konjac and weeds was>5,which indicated that it was safe for konjac.[Conclusions]The results showed that there was not significant toxicological risk to the soil ecology and konjac with quizalofop application at≤56.25 g a.i./ha,so it can be used safely in the konjac.