title: The effects of woodchip- and straw-derived biochars on the persistence of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in soils.
abstract: Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. This study assessed the influence of two biochars, made from woodchips and straw at a pyrolysis temperature of 725°C and applied to a loamy sand and a sandy soil in the concentration of 5.3 g 100 g(-1) sandy soil and 4.1 g 100 g(-1) loamy sand soil, or 53 t ha(-1) for both soil types, on degradation of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Soils were spiked with 50 mg MCPA kg(-1) soil. In the sandy soil, significantly more MCPA remained after 100 days if amended with straw-derived biochar in comparison to wood-derived biochar. Both biochars types significantly increased urease activity (p<0.05) after 37 days in the loamy sand soil, but these differences disappeared after 100 days. A root and shoot elongation test demonstrated that the soils containing straw-derived biochar and spiked with MCPA, showed the highest phytotoxicity. Both biochars were found to retard MCPA degradation in loamy sand and sandy soils. This effect could not be explained only by sorption processes due to comparatively low developed micro/mesoporous structure of both biochars shown by BET surface analysis. However, an enhanced MCPA persistence and soil toxicity in sandy soil amended with straw biochar was observed and further studies are needed to reveal the responsible mechanisms.
authors.affiliation: Institute of Microbiology & Biotechnology, University of Latvia, 4 Kronvalda Boulevard, Riga LV-1010, Latvia. Electronic address: olga.muter@inbox.lv.
authors.forename: Olga
authors.initials: O
authors.lastname: Muter
authors.affiliation: Institute of Microbiology & Biotechnology, University of Latvia, 4 Kronvalda Boulevard, Riga LV-1010, Latvia.
authors.forename: Andrejs
authors.initials: A
authors.lastname: Berzins
authors.affiliation: Latvia University of Agriculture, 2 Liela Street, Jelgava LV-3001, Latvia.
authors.forename: Silvija
authors.initials: S
authors.lastname: Strikauska
authors.affiliation: Institute of Food Safety, Animal Health and Environment "BIOR", 3 Lejupes Street, Riga LV-1076, Latvia.
authors.forename: Iveta
authors.initials: I
authors.lastname: Pugajeva
authors.affiliation: Institute of Food Safety, Animal Health and Environment "BIOR", 3 Lejupes Street, Riga LV-1076, Latvia.
authors.forename: Vadims
authors.initials: V
authors.lastname: Bartkevics
authors.affiliation: Latvian State Institute of Wood Chemistry, 27 Dzerbenes Street, Riga LV-1006, Latvia.
authors.forename: Galina
authors.initials: G
authors.lastname: Dobele
authors.affiliation: Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014 Tartu, Estonia.
authors.forename: Jaak
authors.initials: J
authors.lastname: Truu
authors.affiliation: Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise Street, 51014 Tartu, Estonia.
authors.forename: Marika
authors.initials: M
authors.lastname: Truu
authors.affiliation: BlackCarbon A/S, Barritskovvej 36, 7150 Barrit, Denmark; University of Kassel, Steintr. 19, 37213 Witzenhausen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Steiner
mesh_terms: D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D000327:Adsorption; D001673:Biodegradation, Environmental; D002606:Charcoal / Q000737:chemistry*; D018525:Germination / Q000187:drug effects; D006540:Herbicides / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D016062:Porosity; D012434:Secale / Q000187:drug effects / Q000254:growth & development; D012639:Seeds / Q000254:growth & development; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism / Q000633:toxicity; D013696:Temperature
chemical_list: D006540:Herbicides; D012987:Soil; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; D008456:2-Methyl-4-chlorophenoxyacetic Acid
keywords: Biochar; Biodegradation; MCPA; Microbial enzyme activity; Toxicity