Pedosphere 9(1): 91--96, 1999
ISSN 1002-0160/CN 32-1315/P
©1999 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Assessing soil available potassium by cation exchange membrane and conventional chemical extractions |
| LIU Zhao-Hui1, J. SCHOENAU2, QIAN Pei-Yuan2 and NIE Yan3 |
1 China Agricultural University, Beijing 100094 (China)
2 Department of Soil Science, University of Saskatchewan, Saskatoon S7N 5A8 (Canada)
3 Center Lab., Shandong Academy of Agricultural Sciences, Jdnan 250100 (China) |
| ABSTRACT |
| Four testing methods using cation exchange membrane (CEM), ammonium acetate, ASI (0.25 mol L-1 NaHCO3+0.01 mol L-1 EDTA +0.01 mol L-1 NH4F) and 1.0 mol L-1 boiling nitric acid, respectively, were used to evaluate soil available K. The soil K tested by CEM was significantly correlated with that by the other (conventional) methods (r2=0.43**~0.95***). The soil K tested by CEM saturated with NH4HCO3 (15 min extraction) was most closely correlated with that by the other methods (r2=0.60***~0.95***). Potassium availability, as predicted by soil test, was comparable to actual K uptake by canola and wheat grown on the soils in growth chamber. Regression analyses showed that plant K uptake was more closely correlated with K extracted by CEM (r2=0.56***~0.81***) than that by the conventional methods (r2=0.46***~; 0.81***), most closely correlated with that by NH4HCO3-saturated CEM for 15 min (r2=0.81***), and worst correlated with that by HNO3 (r2=0.45**~0.72***). |
| Key Words: canon exchange resin membrane, conventional chemical extractions, soil available potassium |
| Citation: Liu, Z. H., Schoenau, J., Qian, P. Y. and Nie, Y. 1999. Assessing soil available potassium by cation exchange membrane and conventional chemical extractions. Pedosphere. 9(1): 91-96. |
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