除草剂草甘膦对棉田土壤酶活性的影响

为了明确草甘膦对棉田土壤酶活性的影响,于2013年进行室内模拟试验,分别研究了草甘膦不同处理对河南安阳和安徽安庆棉田土壤中过氧化氢酶、脲酶、磷酸酶活性的影响。结果表明,草甘膦按照50~5000mg·kg-1处理对2个采样点土壤中的过氧化氢酶均有抑制作用,并且浓度越高,抑制作用越强;50、250、500mg·kg-1处理对这2个棉田土壤脲酶的影响表现为先抑制后激活,而5000 mg·kg-1处理对安庆棉田土壤脲酶表现为先抑制后激活,对安阳棉田则表现抑制作用;500 mg·kg-1处理对安阳棉田土壤磷酸酶表现为抑制作用,对安庆棉田则表现激活效应,而5000 mg·kg-1处理对这2个棉田磷酸酶均表现出激活效应。统计分析表明,50、250 mg·kg-1处理对这2个棉田土壤过氧化氢酶、脲酶、磷酸酶活性无显著影响,500 mg·kg-1处理对土壤酶活性有显著的影响,但随着培养时间延长逐渐恢复到对照水平,5000 mg·kg-1处理对土壤酶活性的影响达到极显著水平。

Effects of Glyphosate on Soil Enzyme Activities in Cotton Fields

The effects of glyphosate on the activities of catalase, urease, and phosphatase were determined indoor in soil samples collected from cotton fields in Anyang, Henan Province and Anqing, Anhui Province, China, in 2013. Catalase activity was found to be concentration-dependently inhibited by 50-5000 mg·kg^-1 glyphosate. In both soil samples, urease activity was inhibited then stimulated by lower concentrations of glyphosate (50, 250 mg·kg^-1, 500 mg·kg^-1). After being treated by the higher concentration of glyphosate (5000 mg·kg^-1), Anyang cotton field soil urease was continuously inhibited, while Anqing cotton field soil urease was first inhibited then stimulated. As for phosphatase activities, it was inhibited with 500 mg·kg^-1 glyphosate in Anyang sample, but stimulated in Anqing sample, while it was stimulated with 5000 mg·kg^-1 glyphosate in both samples.