草甘膦对桉树林地土壤酶活性的影响

Effects of Glyphosate on Soil Enzyme Activities in Eucalyptus Forest Land

为探明施用草甘膦对桉树林地土壤酶活性的影响,在广西壮族自治区国有维都林场三年生桉树林地随机选择8块样地开展了试验。2020年和2021年连续2年对其中4块样地喷施41%草甘膦异丙胺盐水剂清除杂草和矮灌木丛,另外4块样地采用人工除草作对照,其他管护方式相同。2022年4月采集土壤样品,测定其土壤酶活性。结果表明:与对照样地相比,施用草甘膦的样地各土层土壤过氧化氢酶活性均显著降低,0~5 cm、>5~10 cm、>10~20 cm和>20~50 cm土层过氧化氢酶活性分别降低了25.98%、20.82%、21.85%和20.14%;各土层酸性磷酸酶活性均较对照样地下降,0~5 cm、>5~10 cm、>10~20 cm和>20~50 cm土层分别降低了19.16%、22.47%、2.29%和3.79%,仅0~5 cm和>5~10 cm土层降低显著;各土层纤维素酶活性也均较对照样地降低,0~5 cm、>5~10 cm、>10~20 cm和>20~50 cm土层分别降低了27.01%、5.10%、4.17%和5.32%,仅0~5 cm土层降低显著;各土层土壤脲酶和蔗糖酶活性均较对照样地有一定程度的提高,但差异不明显。由此表明,在桉树林地施用除草剂草甘膦,会明显降低表层土壤过氧化氢酶、纤维素酶和酸性磷酸酶的活性,对林地的养分循环造成不利影响,降低土壤肥力。

In order to investigate the effects of glyphosate on soil enzyme activities in eucalyptus forest land,eight experiment plots were randomly arranged from the three-year-old eucalyptus forest in Guangxi State-owned Weidu Forest Farm.In 2020 and 2021,four plots were sprayed with 41%glyphosate isopropylamine salt water for 2 consecutive years to clear weeds and undergrowth,taking the other four plots used manual weeding as a control,with the same management and protection methods.Soil samples were collected in April 2022 to determine soil enzymes activities.The results showed that compared with the control plots,the catalase activity in each soil layer of the glyphosate application plots decreased significantly,and the catalase activity in 0-5 cm,>5-10 cm,>10-20 cm and>20-50 cm soil layers reduced by 25.98%,20.82%,21.85%and 20.14%,respectively.The activity of acid phosphatase in each soil layer was lower than that of the control plots.The activity of acid phosphatase in 0-5 cm,>5-10 cm,>10-20 cm and>20-50 cm soil layers decreased by 19.16%,22.47%,2.29%and 3.79%,respectively,while that in 0-5 cm and 5-10 cm soil layers decreased significantly.Compared with the control plots,the cellulase activity in each soil layer also decreased,with a decrease of 27.01%,5.10%,4.17%,and 5.32%in the 0-5 cm,>5-10 cm,>10-20 cm and>20-50 cm soil layers,respectively.Only the 0-5 cm soil layer showed a significant decrease in cellulase activity.Compared with the control plots,the activities of soil urease and soil saccharase in each soil layer were improved to a certain extent,but the difference was not obvious.In conclusion,the application of herbicide glyphosate in eucalyptus forest land could significantly reduce the activities of catalase,cellulase and acid phosphatase in the surface soil,adversely affect the nutrient cycle of the forest land,and reduce soil fertility.