Pedosphere 5(4): 289--303, 1995
ISSN 1002-0160/CN 32-1315/P
©1995 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Mobilization of phosphorus by naturally occurring organic acids in Oxisols and Ultisols |
| HAN Xing-Guo1,2 and C. F. JORDAN2 |
1 Center of Plant Ecology, Institute of Botany, Chinese Academy of Sciences, 141 Xiwai Street, Beijing 100044 (China)
2 Institute of Ecology, University of Georgia, Athens, GA 30602 (U.S.A) |
| ABSTRACT |
| Citric and malic acids at concentrations of 0.1, 1.0, 10, and 100 mmol/L were added to three Ultisols and one Oxisol. The amount of P in solution increased with increasing organic acid concentrations, while the amount of Fe- and Al-bound P decreased. This result suggested that naturally occurring products of organic matter decomposition could increase the P availability to plants in soils where there is a relatively large pool of Fe- and Al-bound P. The interactions between citric and malic acids at the above concentrations, and P added at rates of 10, 20, 40, and 80 mg/kg were determined. At zero levels of organic acids, all added P became either labile or bound, and greater proportions remained soluble as the concentration of organic acids increased, which suggested that organic acids reduced fixation of dissolved P in Fe- and Al-rich soils. Agricultural practices which increase organic matter input on P-deficient acid soils could decrease P deficiency. This would be important in many tropical and subtropical regions where these soils are common, and where the costs of fertilizers and lime are relatively high. |
| Key Words: acid soils, adsorption, chelation, phosphorous mobilization, solubilization |
| Citation: Han, X. G. and Jordan, C. F. 1995. Mobilization of phosphorus by naturally occurring organic acids in Oxisols and Ultisols. Pedosphere. 5(4): 289-303. |
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