title: Assessing biochar's ability to reduce bioavailability of aminocyclopyrachlor in soils.
abstract: Aminocyclopyrachlor is a pyrimidine carboxylic acid herbicide used to control broadleaf weeds and brush. Amending soil with activated charcoal is recommended to prevent off-site transport of aminocyclopyrachlor and non-target plant damage. We used the batch-equilibrium method to determine the concentration of aminocyclopyrachlor in a pseudo-steady state with biochar, soil, and biochar-soil systems (<10% biochar by weight). We observed that aminocyclopyrachlor is mobile in soils. Soil incorporation of activated charcoal removed nearly all of the aqueous aminocyclopyrachlor thereby limiting its bioavailability to non-target flora. On the other hand, biochars were less effective than activated charcoal. Biochar produced from olive mill waste feedstock was the most effective biochar that we assessed for reducing the aqueous herbicide concentration. Although these biochars reduced the aminocyclopyrachlor concentration, they would not be practical remediation media due to the extraordinarily high application rates required to reduce the concentration by 50% (2.13 × 10(5) kg ha(-1)-7.27 × 10(5) kg ha(-1)).
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, United States. Electronic address: Jennifer.Rittenhouse@ars.usda.gov.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Rittenhouse
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, United States.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Rice
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, United States.
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Spokas
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, 439 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, United States.
authors.forename: William C
authors.initials: WC
authors.lastname: Koskinen
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006540:Herbicides / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry
chemical_list: D006540:Herbicides; D011743:Pyrimidines; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; C560341:aminocyclopyrachlor
keywords: Aminocyclopyrachlor; Auxin; Herbicide