title: Effect of low-molecular-weight organic acids on kinetics release and fractionation of phosphorus in some calcareous soils of western Iran.
abstract: Organic acid has been related to nutrient mobilization, mainly in phosphorus (P) insoluble utilization, and therefore enhances P bioavailability. In this study, we examined the effect of low-molecular-weight organic acids (malic, citric, and oxalic acids) on P release of some calcareous soils from western Iran. Fractionation and speciation of P in the soil solution were studied at the initial and final P release. Significantly different quantities of P were extracted by the organic acids. On average the maximum (1,554.9 mg kg(-1)) and the minimum (1,260.5 mg kg(-1)) P were extracted by 10 mM oxalic and malic acid, respectively. Power equation described well P release. In the initial stage of P release, the solution samples in soils were supersaturated with respect to hydroxyapatite and β-TCP. At the end of P release, all solutions were undersaturated with phosphate minerals. The percentage of Fe-Al oxide fraction generally increased after P release, while carbonate and residual P fractions were decreased in all organic acids. Compared with the native soils, adding malic and citric acids had no effect on Fe-Al oxide fraction, but oxalic acid significantly reduced this fraction.
authors.affiliation: Department of Soil Science, College of Agriculture, Bu-Ali Sina University, Hamadan, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Taghipour
authors.forename: M
authors.initials: M
authors.lastname: Jalali
mesh_terms: D000144:Acids, Acyclic / Q000737:chemistry*; D002119:Calcium Carbonate / Q000737:chemistry; D005591:Chemical Fractionation; D019343:Citric Acid / Q000737:chemistry; D007492:Iran; D007700:Kinetics; D008293:Malates / Q000737:chemistry; D008956:Models, Chemical; D008970:Molecular Weight; D019815:Oxalic Acid / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D000144:Acids, Acyclic; D008293:Malates; D012987:Soil; D012989:Soil Pollutants; D010758:Phosphorus; D019343:Citric Acid; C030298:malic acid; D019815:Oxalic Acid; D002119:Calcium Carbonate