Location: Soil and Water Management ResearchTitle: Evaluating agricultural management effects on alachlor availability: Tillage, green manure, and biochar Author
|Mendes, Kassio - Universidad De Sao Paulo|
|Hall, Kathleen - University Of Minnesota|
|Koskinen, William - University Of Minnesota|
|Tornisielo, Valdemar - Universidad De Sao Paulo|
Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2017
Publication Date: 9/29/2017
Citation: Mendes, K.F., Hall, K.E., Spokas, K.A., Koskinen, W.C., Tornisielo, V.L. 2017. Evaluating agricultural management effects on alachlor availability: Tillage, green manure, and biochar. Agronomy. 7(4):64. https://doi.org/10.3390/agronomy7040064.
DOI: https://doi.org/10.3390/agronomy7040064 Interpretive Summary: Assessing the difference between tillage practices and biochar amendment addition on pesticide sorption. Agricultural management practices change sorption properties of the soil. In this study, we evaluated the differences between tillage and biochar additions on the sorption capacity for alachlor. Surprisingly, there was no difference in the sorption capacity of soils under different tillage managements at three sites across the Midwest USA (chisel plow vs. ridge tillage). On the other hand, biochar amendments increased alachlor sorption between 4x and 33x compared to the unamended soil. This study highlights the larger impact of biochar additions have over tillage practices on improving pesticide sorption capacities. These results are significant to farmers and policy makers and will assist scientists and engineers in developing improved biochar guidelines for pesticide fate and transport after soil addition.
Technical Abstract: Agricultural and soil management practices have been reported to affect alachlor sorption-desorption and degradation rates. The objectives of this study were to: (a) assess differences in alachlor sorption due to tillage treatments (chisel plow and ridge tillage) on soils from three Midwestern U.S. states; and (b) determine the effect of various soil amendments on the sorption-desorption and mineralization of alachlor. Soils were amended at a rate of 10% (w/w) with biochars derived from soybean stover, sugarcane bagasse, and wood chips, as well as the uncharred feedstock materials. Sorption-desorption studies were performed using the batch equilibration method. Alachlor mineralization was evaluated in a 30-day incubation. Surprisingly, tillage management did not affect alachlor sorption to soil across the three sites, despite the fact that the tillage operations were imposed for 4 years (P>0.05). While sorption coefficient (Kd) values for alachlor were relatively low in the three unamended soils (Kd = 1.76, 1.73, and 1.15 L kg-1 for IL, MN, and PA soils, respectively), biochar amendments increased alachlor sorption between 4x and 33x compared to the unamended soil. Amendments also affected alachlor mineralization such that degradation was slower in both biochar and raw feedstock amended soils. This study highlights the larger impact of biochar addition than tillage practices on altering immediate alachlor sorption capacities. Biochar additions will affect the availability of alachlor for transport and degradation.