Effect of Carbonaceous Soil Amendments on Potential Mobility of Weak Acid Herbicides in Soil
Use of carbonaceous amendments in soil has been proposed to decrease potential offsite transport of weak acid herbicides and metabolites by increasing their sorption to soil.The effects of organic olive mill waste,biochars from different feed stocks,and humic acid bound to clay on sorption of 4-chloro-2-methylphenoxyacetic acid (MCPA),aminocyclopyrachlor,or indaziflam-acid metabolite to soils with varying physical and chemical properties were determined.At natural agricultural pH soil levels,these chemicals are anionic and weakly sorbed to soils; sorption of the three weak acids on soil was in the order MCPA (Kf=0.1) <aminocyclopyrachlor (Kf=0.3) <indaziflam-acid (Kf=1.6).Results indicate that not all carbonaceous amendments,including biochars,increase sorption,thereby decreasing the potential for offsite transport.The amount and composition of the organic amendment,along with pH of the system,affect sorption and potential offsite transport.For instance,depending on the feedstock of the biochar and the method of production,changes in sorption ranged from no effect,to a decrease by a factor of 3.3 X,to an increase of 383 X upon addition of amendment to soil.In contrast,activated charcoal increased sorption by >10,000 X.While generalizations have been made that soil sorption of nonpolar,neutral,or weakly basic chemicals increases by the addition of different carbonaceous amendments,no such generalizations can be made for weak acids.More work on properties of these amendments,biochars in particular,and how they affect weak acid sorption is required.
Herbicide MCPA Aminocyclopyrnachlor Indaziflam acid Sorption Biochar
William C.Koskinen Alegria Cabrera Kurt A.Spokas Lucia Cox Jennifer L.Rittenhouse Pamela J.Rice
USDA-Agficultural Research Service,1991 Upper Buford Cir.,Rm.439,St.Paul,MN,USA Instituto de Recursos Naturales y Agrobiologia de Sevilla(IRNASE-CSIC),P.O.Box 1052,41080 Sevilla,Sp lnstituto de Recursos Naturales y Agrobiologia de Sevilla(IRNASE-CSIC),P.O.Box 1052,41080 Sevilla,Sp
国际会议
the 16th Meeting of the International Humic Substances Society (第十六届国际腐殖物质学会大会(IHSS 16))
杭州
英文
281-283
2012-09-09（万方平台首次上网日期，不代表论文的发表时间）