Pedosphere 18(2): 248--256, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Phosphorus changes and sorption characteristics in a calcareous soil under long-term fertilization |
GUO Sheng-Li1,2 , DANG Ting-Hui1 and HAO Ming-De2 |
1 Northwest Sci-Tech University of Agriculture and Forestry, Yangling, Shnanxi 712100 (China). E-mail: slguo@ms.iswc.ac.cn
2 Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling Shaanxi 712100 (China) |
| ABSTRACT |
| Knowledge of phosphorus (P) behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality. The long-term (1984-1997) effects of various fertilization treatments on P changes and sorption isotherms as well as the relationship of soil properties to P sorption and P forms were evaluated in an Ustic Isohumisol, a calcareous soil, on the Loess Plateau, China. Compared to 1984, after 13 years of crop production, total soil P in the no-P treatments (control and N treatment) decreased by 5%-7%, but in the phosphorus fertilizer alone (P), nitrogen and phosphorus fertilizers in combination (NP), manure alone (M), and nitrogen and phosphorus fertilizers and manure in combination (NPM) treatments, it increased by 22%, 19%, 28%, and 58%, respectively. Residual fertilizer P was found mainly in NH4Ac-soluble P (Ca8-P), followed by NaHCO3-soluble P (NaHCO3-P), and NH4F-soluble P (A1-P). Phosphorus sorption in the soils with different fertilization practices fit the Langmuir equations. Phosphorus sorption capacity in the no-P treatments increased, whereas it decreased in the P-included treatments (P, NP, and NPM treatments). Phosphorus sorption maximum (Qm) was significantly and negatively correlated to inorganic P including NaHCO3-P, Ca8-P, NaOH-Na2CO3-soluble P (Fe-P), and Al-P (P ≤0.01). Moreover, long-term fertilization increased soil organic carbon in the NP, M, and NPM treatments and decreased pH in the NP and NPM treatments. Thus, the ability of the soil to release sorbed P to the environment increased under long-term P fertilization. |
| Key Words: calcareous soil, long-term fertilization, P accumulation, P sorption, P transformations |
| Citation: Guo, S. L., Dang, T. H. and Hao, M. D. 2008. Phosphorus changes and sorption characteristics in a calcareous soil under long-term fertilization. Pedosphere. 18(2): 248-256. |
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