Pedosphere 20(3): 368--377, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Potassium fractions in soils as affected by monocalcium phosphate, ammonium sulfate, and potassium chloride application |
WANG Huo-Yan , ZHOU Jian-Min, DU Chang-Wen and CHEN Xiao-Qin |
| State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China) |
| ABSTRACT |
| Soil potassium (K) deficiency has been increasing over recent decades as a result of higher inputs of N and P fertilizers concomitant with lower inputs of K fertilizers in China; however, the effects of interactions between N, P, and K of fertilizers on K status in soils have not been thoroughly investigated for optimizing N, P, and K fertilizer use effciency. The influence of ammonium sulfate (AS), monocalcium phosphate (MCP), and potassium chloride application on K fractions in three typical soils of China was evaluated during 90-d laboratory soil incubation. The presence of AS significantly altered the distribution of native and added K in soils, while addition of MCP did not significantly affected K equilibrium in most cases. Addition of AS significantly increased water-soluble K (WSK), decreased exchangeable K (EK) in almost all the soils except the paddy soil that contained considerable amounts of 2:1 type clay minerals with K added, retarded the formation of fixed K in the soils with K added, and suppressed the release of fixed K in the three soils without K added. These interactions might be expected to influence the K availability to plants when the soil was fertilized with AS. To improve K fertilizer use effciency, whether combined application of AS and K was to be recommended or avoided should depend on K status of the soil, soil properties, and cropping systems. |
| Key Words: fertilizers, K availability, K fixation, K release |
| Citation: Wang, H. Y., Zhou, J. M., Du, C. W. and Chen, X. Q. 2010. Potassium fractions in soils as affected by monocalcium phosphate, ammonium sulfate, and potassium chloride application. Pedosphere. 20(3): 368-377. |
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