Pedosphere 21(3): 365--372, 2011
ISSN 1002-0160/CN 32-1315/P
©2011 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils and potassium recommendations for crops in southern Brazil |
| L. BORTOLON, C. GIANELLO, S. WELTER, R. G. O. ALMEIDA and E. GIASSON |
| Department of Soil Science, Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil) |
| ABSTRACT |
| Simultaneous multi-element extraction has been increasing worldwide to improve soil laboratory testing quality and efficiency. This study sought to investigate the applicability of the Mehlich-1, Mehlich-3, and resin methods for simultaneous extraction of soil available P, K, Ca and Mg as well as the effect of using conversion equations on nutrient recommendations for crops. Topsoil (0--20 cm) samples were taken from the most representative soils types used for crop production in southern Brazil with a wide range of chemical, physical, and mineralogical properties. Soil P, K, Ca, and Mg were simultaneously extracted using 1.0 mol L-1 KCl, Mehlich-1, and Mehlich-3 solutions, and membrane resin. The amounts of P extracted with the Mehlich-1 method were, on average, 50% lower than those extracted with the resin and Mehlich-3 methods. However, the resin method extracted the lowest amounts of K, Ca and Mg. The use of conversion equations was suitable and it did not affect negatively the K recommendations for crops grown on soils of southern Brazil. |
| Key Words: Mehlich-1, Mehlcih-3, membrane resin, multi-element extraction, soil testing |
| Citation: Bortolon, L., Gianello, C., Welter, S., Almeida, G.O. and Giasson, E. 2011. Simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils and potassium recommendations for crops in southern Brazil. Pedosphere. 21(3): 365-372. |
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