Pedosphere 15(1): 72--77, 2005
ISSN 1002-0160/CN 32-1315/P
©2005 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Chemical criteria to assess risk of phosphorus leaching from urban soils |
ZHANG Gan-Lin1 , W. BURGHARDT2 and YANG Jin-Ling1 |
1 State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China). E-mail: gLzhang@issas.ac.cn
2 Department of Applied Soil Science, University of Duisburg-Essen, Essen 45117 (Germany) |
| ABSTRACT |
| Soils from urban and suburban areas are normally enriched with phosphorus (P). Sixteen urban soils with a wide range of total P concentrations under typical urban land uses were sampled and analyzed for extractable P concentrations using water, sodium bicarbonate and citric acid. Meanwhile the soils were artificially leached in columns and P concentrations in the leachates were determined. With linear regression a two-stage linear relationship was found to exist between concentrations of P in the leachates and soil P contents obtained by various chemical measurements, i.e., there was a "change-point" denoting the critical threshold value for extractable P between the regression lines, above which concentrations of P in leachates increased substantially. These threshold "change-point" values were 1.5 mg kg-1 for water-soluble P and CaCl2-P, 25 mg kg-1 for Olsen-P, and 250-350 mg kg-1 for citric acid-P with the sharpest change and the best predictor [r2 (upper) = 0.928, r2 (lower) = 0.807] appearing for Olsen-P. These "change-points" were considered important criteria in assessing the risk of P leaching from urban soils and could be used as standards to delineate and target hazardous areas in urban and suburban areas. |
| Key Words: assessment, leaching, phosphorus, urban soils |
| Citation: Zhang, G. L., Burghardt, W. and Yang, J. L. 2005. Chemical criteria to assess risk of phosphorus leaching from urban soils. Pedosphere. 15(1): 72-77. |
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