桉树人工林土壤草甘膦短期消解规律研究  

Short-term Degradation of Glyphosate in Eucalypt Plantation Soils

作　　者：陈博昊 吴立潮[1] 石天良 朱华生 马舒娴 唐亚斌 奉文让 陈永桀 张敬 陈利军 石驭天 CHEN Bohao;WU Lichao;SHI Tianliang;ZHU Huasheng;MA Shuxian;TANG Yabin;FENG Wenrang;CHEN Yongjie;ZHANG Jing;CHEN Lijun;SHI Yutian(College of Forestry,Central South University of Forestry and Technology,Key Laboratory of Soil and Water Conservation and Desertification of Hunan Provincial Higher Education University,Changsha 410004,Hunan,China;Guangxi Zhuang Autonomous Region State-owned Gaofeng Forest Farm,Nanning 530006,Guangxi,China;Guangxi Zhongnan Linhai Biotechnology Co.,Ltd,Nanning 530006,Guangxi,China;Jiejiarun Technology Group Co.,Ltd,Nanning 530006,Guangxi,China)

机构地区：[1]中南林业科技大学林学院/水土保持与荒漠化湖南省高等学校重点实验室,湖南长沙410004 [2]广西壮族自治区国有高峰林场,广西南宁530006 [3]广西中南林海生物科技有限公司,广西南宁530006 [4]捷佳润科技集团股份有限公司,广西南宁530006

出　　处：《桉树科技》2023年第4期17-24,共8页Eucalypt Science & Technology

基　　金：广西自筹经费林业科技项目(桂林科研﹝2022ZC﹞第29号);“十三五”国家重点研发计划项目子课题(2016YFD0600505)。

摘　　要：在桉树生产中常使用大量草甘膦除草剂,当过量的草甘膦超过了土壤的降解能力时,无法被迅速消解的草甘膦即滞留在土壤中,从而影响土壤健康并造成地力损失。为探明桉树人工林生产中草甘膦是否存在减量空间和探讨林下土壤草甘膦残留量短期的变化规律,以第三代新造尾巨桉人工林地为研究对象,将当地标准草甘膦喷施浓度(3.375 kg a.i.·hm^(-2))设为100%,在此基础上设置了50%、75%、125%浓度和人工除草处理。喷施草甘膦后10、50、100 d分别采集土壤表层(0~20 cm)和亚表层(20~40 cm)样品,以检验除草效果。结果表明:75%减量处理与当地标准浓度100%处理间除草效果差异不显著;除125%浓度外,100d时土壤表层与亚表层中草甘膦残留量均达国际安全标准(<0.1 mg·kg^(-1))。草甘膦的分解产物AMPA检出率在100 d内随时间变化不断增加。草甘膦半衰期在高浓度处理下长于低浓度处理,在50~100 d长于10~50 d,在0~20 cm长于20~40 cm。研究结果认为75%处理可达到预期除草效果,说明桉树人工林草甘膦的施用存在减量空间,结合助剂的使用还可进一步减量。桉树林下土壤中草甘膦半衰期与喷施浓度呈正相关,且表层土壤中草甘膦半衰期更短。A large amount of glyphosate herbicide is used in eucalypt afforestation.When the applied glyphosate exceeds the soil’s degradation capacity,glyphosate cannot be quickly broken down and remains in the soil potentially affecting soil health and fertility.In order to investigate whether there is potential to reduce glyphosate use in eucalypt afforestation and to explore the short-term change rules of glyphosate residue in soils,this study examined a third generation Eucalyptus urophylla×E.grandis plantation as the research object.The standard local glyphosate concentration(3.375 kg a.i.·hm^(−2))was set as 100%base treatment,and then doses of 50%,75%and 125%of the base treatment were applied along with an artificial(manual)weeding treatment.Soil surface(0~20 cm)and subsurface(20~40 cm)soil samples were collected at 10,50 and 100 days after spraying the glyphosate to test herbicide impacts on the soil.The results showed that there was no significant difference in weeding effect between the 75%reduction treatment and the 100%local standard concentration treatment.Except for the 125%concentration treatment,the residual amount of glyphosate in surface and subsurface soil reached the international safety standard(<0.1 mg·kg^(−1))by 100 days after application.The detection rate of AMPA (a decomposition product of glyphosate) increased with time up to 100 days. The ranks of glyphosate half-life were: high concentration treatment > low concentration treatment, 50 ~ 100 d > 10 ~ 50 d, and 0 ~ 20 cm > 20 ~ 40 cm. The results showed that the 75% reduction treatment can achieve expected effects, indicating that there is space for reduction of glyphosate application in eucalypt plantations whilst the use of additives could potentially further reduce the amounts of glyphosate applied. Overall, it was clear that glyphosate half-life in eucalypt plantation soil is positively correlated with the concentration of chemical applied and that it is shorter in surface than deeper soil layers.

关 键 词：农药减量 草甘膦 残留量 桉树人工林 消解规律 

分 类 号：S767.5[农业科学—森林保护学]