Considerations on the evaluation of the fertility of oxisols in Brazil |
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Authors: | Masanori Miyake |
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Institution: | Tropical Agriculture Research Center, Yatabe, Ibaraki 305, Japan |
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Abstract: | Based on the analysis of some of the physical and chemical properties of the reddish-colored soils from southeast Brazil four fertility classes of soils were proposed. The soils of class 1 which are characterized by a low inherent fertility are sandy soils which become less fertile after cultivation. The soils of class 2 which are derived from carbonate-cemented sandstone have a high base status under forest vegetation, but become very poor after cultivation and erosion. The soils of class 3 which have a moderate inherent fertility become more fertile after cultivation along with liming and fertilization. Class-4 soils are inherently fertile and their fertility can be maintained and enhanced easily by management practices. The potentially self-improving soils of classes 3 and 4 have a phosphate sorption coefficient above 1000 which corresponds to a definite content in clay, free Fe, total P, and water-soluble silica. |
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