Resumo

MILLAN, Guillermo; VAZQUEZ, Mabel; TERMINIELLO, Antonino  e  SANTOS SBUSCIO, Diego. Application of basic amendments on acid soils of the Pampa Region: effect on the soil exchange complex. Cienc. suelo [online]. 2010, vol.28, n.2, pp.131-140. ISSN 1850-2067.

Edaphic acidity causes productivity problems due to microbiological and nutritional disturbances and Al+3 phytotoxicity. The purpose of this study was to: a) evaluate the cation exchange capacity and the amount of basic nutrients present in some acid soils of the Pampa Region, b) evaluate the exchangeable Al3+ concentration, and c) assess the effect of different rates and types of alkaline amendments on the exchange complex. Real and potential pH, the exchange complex and exchangeable Al3+ were studied in 10 acidic Argiudoll and Hapludoll soils. The same analyses were conducted on an Entic Hapludoll treated with different rates and types of amendments. In addition, the cation exchange capacity at each soil pH level was evaluated. The soils presented Ca+2 deficiency relative to Mg+2 and K+, and to a lesser extent low Mg+2 concentrations relative to K+. High to slightly acidic real pH corresponded with a high/moderately acidic potential pH. Liming increased the cation exchange capacity and exchangeable Ca+2. Although exchangeable Al3+ was not present at toxic levels in the untreated soils, addition of any amendment combination and rate reduced its concentration 4 to 5-fold. Gypsum did not modify the calcite effect on Al3+, but its addition to dolomite reduced carbonate efficiency. For each amendment, the best rates for lowering exchangeable Al+3 were 1,500 and 2,000 kg ha-1.

Palavras-chave : Calcite; Dolomite; Gypsum; Real and potential pH.

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