Effects of Dissolved Organic Carbon on Phosphate Retention on Two Calcareous Soils

• Published in: Journal of agricultural and food chemistry 2005-01, Vol.53 (1), p.84-89
• Main Authors: Fernández-Pérez, Manuel, Flores-Céspedes, Francisco, González-Pradas, Emilio, Ureña-Amate, María Delores, Villafranca-Sánchez, Matilde, Socías-Viciana, María, Pérez-García, Susana
• Format: Article
• Language: English
• Subjects: Adsorption; Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Biological and physicochemical phenomena; Biological and physicochemical properties of pollutants. Interaction in the soil; calcareous soils; Calcic Regosols; Carbon - pharmacology; Chemical Phenomena; chemical precipitation; Chemical, physicochemical, biochemical and biological properties; Chemistry, Physical; dissolved organic carbon; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Luvic Xerosols; Mineral components. Ionic and exchange properties; Natural water pollution; peat; Permeability; phosphates; Phosphates - analysis; Phosphates - chemistry; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Plants - metabolism; Pollution; Soil - analysis; Soil and sediments pollution; Soil and water pollution; soil chemistry; soil fertility; Soil science; sorption; Spain; tannins; Water treatment and pollution
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf048767o

To evaluate the effects of dissolved organic carbon (DOC) on phosphate retention (including both sorption and/or precipitation reactions) on soils, experiments were performed by using two typical calcareous soils from southeastern Spain (Calcic Regosol and Luvic Xerosol) and two different types of DOC:  (1) extracts from a commercial peat (DOC-PE) and (2) high-purity tannic acid (DOC-TA). The experiments were carried out from a 0.01 M CaCl2 aqueous medium at 25 °C. The results obtained show that the presence of both DOC-PE and DOC-TA, over a concentration range of 15 (DOC-15) to 100 (DOC-100) mg L-1, produces in all cases a decreasing amount of phosphate retained in the soils studied, the decrease observed being higher when DOC-PE is used as source of DOC. The values of the decrease observed when DOC-PE was added ranged between 19.9% (DOC-15) and 15.6% (DOC-100) for the Calcic Regosol and between 17.3% (DOC-70, DOC-100) and 14.6% (DOC-15) for the Luvic Xerosol. The variation observed when DOC-TA was added ranged between 8.5% (DOC-100) and 0.5% (DOC-35) for the Calcic Regosol and between 7.0% (DOC-100) and 1.0% (DOC-15) for the Luvic Xerosol. Keywords: Phosphate; sorption; precipitation; calcareous soil; dissolved organic carbon