Metolachlor Sorption and Degradation in Soil Amended with Fresh and Aged Biochars

• DOI: 10.1021/acs.jafc.6b00246
• Publication Date: 2016-04-06T19:25:37Z
• Authors: Carmen Trigo; Kurt A. Spokas; Kathleen E. Hall; Lucia Cox; William C. Koskinen
• Keywords: Metolachlor; Degradation

Addition of organic amendments such as biochar to soils can influence pesticide sorption–desorption processes and, in turn, the amount readily availability for transport and biodegradation. Sorption–desorption are affected by both physical chemical properties pesticides, well soil–pesticide contact time, or aging. Changes metolachlor with aging soil amended three macadamia nut shell biochars aged 0 (BCmac-fr), 1 year (BCmac-1yr), 2 years (BCmac-2yr) two wood (BCwood-fr) 5 (BCwood-5yr) were determined. Apparent sorption coefficient (Kd-app) values increased incubation time a greater extent compared unamended soils; Kd-app 1.2-fold soil, 2.0-fold BCwood-fr, 1.4-fold BCwood-5yr, 2.4-fold BCmac-fr, 2.5-fold BCmac-1yr, 1.9-fold BCmac-4yr. The increase calculated value was result 15% decrease solution concentration extractable CaCl2 50% very little change sorbed concentration. Differences could possibly be due diffusion less accessible stronger binding sites faster rate degradation (in on labile sites) than desorption, combination soils. These data show that models would overpredict depth movement if effects not considered.