Pedosphere 20(2): 137--145, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of land use conversion from rice paddies to vegetable fields on soil phosphorus fractions |
J. L. DARILEK1,2, HUANG Biao1,2 , LI De-Cheng1, WANG Zhi-Gang1, ZHAO Yong-Cun1, SUN Wei-Xia1 and SHI Xue-Zheng1 |
1 Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);
2 Graduate University of the Chinese Academy of Sciences, Beijing 100039 (China) |
| ABSTRACT |
| Excess phosphorus (P) from agricultural soils contributes to eutrophication in water bodies. Samples (n=60) were taken from sites where rice paddies have been converted to vegetable fields for 0, < 10, 10-20, and > 20 years and analyzed for five inorganic P (Pi) fractions, three organic P (Po) fractions, and several soil parameters to investigate how land use conversion affects Pi and Po fractions in a peri-urban area of China with soils characteristic of many agricultural areas of Asia. Significant increases of 33, 281, 293, and 438 mg kg-1 were found for soluble and loosely bound Pi (SL-Pi), aluminum-bound Pi (Al-Pi), calcium-bound Pi (Ca-Pi), and iron-bound Pi (Fe-Pi), respectively, after conversion from rice paddies to vegetable fields. Most of the increase in Pi was in the form of Fe-Pi, which increased from 8% of total P (TP) on paddy soil to 31% on the soil with > 20-year vegetable cultivation, followed by Al-Pi, which increased from 2% to 19% of TP. For Po fractions, there was no significant change in P concentrations. The conversion of land use from paddy fields to high intensity vegetable fields was causing significant changes in soil P fractions. Management practices were causing a buildup of soil P, primarily in the Fe-Pi fraction, followed by Ca-Pi and Al-Pi fractions. If current trends continue, a 30%-70% increase in TP could be expected in the next 20 years. Farmers in the area should reduce P application and use to maximize P uptake. |
| Key Words: inorganic phosphorus, organic phosphorus, peri-urban agriculture, phosphorus accumulation, soil fertility |
| Citation: Darilek, J. L., Huang, B., Li, D. C., Wang, Z. G., Zhao, Y. C., Sun, W. X. and Shi, X. Z. 2010. Effect of land use conversion from rice paddies to vegetable fields on soil phosphorus fractions. Pedosphere. 20(2): 137-145. |
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