Influence of Wheat Ash on the MCPA Immobilization in Agricultural Soils

Abstract

Burning of crop residues in the fields is a routine post-harvest practice and results in accumulation of ashes in soils. Recent studies have shown that the ashes may significantly contribute to the herbicide sorption in soils. This study was conducted to evaluate the potential role of wheat ash in immobilization of anionic herbicide MCPA in soils. The results showed that wheat ash is highly effective sorbent for herbicide MCPA. Amendment of Fluvi-Gleyic Phaeozem and Eutric Regosol with 1% wheat ash caused a 8-fold and 16-fold increase in MCPA sorption, respectively. Desorption of MCPA was also influenced by wheat ash in soils. The addition of wheat ash to both soils increased the resistant fraction to desorption up to 80%. Generally, the field burning of crop residues appears to increase the sorption of pesticides in agricultural soils and decrease their leaching.

Biochar applications and modern techniques for characterization

“…Amount of total C in organic matter benefits the soil (Morales et al 2015) pH w (-) Determination and attraction of nutrients and mineral ions directly affect the soil surface charge due to the pH of the soil solution (Chintala et al 2014) Microbial habitat Soil microbial biomass, activity, and the degree of response appear to be dependent on nutrient availability increases in soil due to biochar Biochar improves soil sorption capacity of PAHs, pesticides and herbicides, and therefore influence toxicity, transport and fate of such contaminants (Hiller et al 2008) Cation exchange capacity [Av (mmol c kg -1 )]…”

Impacts of Biochar (Black Carbon) Additions on the Sorption and Efficacy of Herbicides

“…For clomazone, a rice crops herbicide, Xu et al (2008) reported an increase in sorption with the addition of burned rice straw to the soil, with an increase of 1.5 and 3 times in the K f values when a silt loam soil was amended with the 0.1 and 0.5% (w/w) respectively. The acidic herbicide MCPA and the effect of wheat ash as soil amendment on its sorption were studied by Hiller et al (2007;2009). The authors observed that the isotherms of MCPA on wheat ash fitted to a Langmuir equation, but sorption on soil and ash amended soil did not fit to any model and calculated the K d values, with a 15 and 10 fold increase when the sandy loam and the sandy soil were amended with 1% (w/w) of wheat ash.…”

“…The successive desorption isotherms could be fitted to the Freundlich, Langmuir, and a combination of both equations. Desorption of MCPA is influenced by the presence of wheat ash in a sandy and sandy loam soil, decreasing MCPA desorption from 77 to 21% in the non amended and wheat ash amended sandy loam soil, and from 45 to 11% in the non amended and amended sandy soil (Hiller et al, 2007;2009). MCPA desorption at high concentration (57 mg L -1 ) the percentage of herbicide desorbed from the wheat ash was similar to the percentages desorbed from the amended soils, however, at the low concentration (5.7 mg L -1 ) decreased the desorption of MCPA from the amendment.…”

Enhanced chlorophenol sorption of soils by rice-straw-ash amendment

“…Extensive studies have focused on the sorptive properties of major constituents of soils, including both minerals and organic matter, for contaminants to elucidate their roles in determining the mobility and bioavailability of contaminants in soils. Recent studies have suggested that the ash arising from burning crop residues may also be a potential sorbent for organic [1][2][3][4][5][6] and inorganic contaminants [7,8] in agricultural soils. The high sorptivity of crop residue ashes has been attributed to the content of black carbon, which is formed from the incomplete combustion of crop residues.…”