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BIBTEX RIS

Calcium Leaching to Increase Rooting Depth in a Brazilian Savannah Oxisol 1

1980; Wiley; Volume: 72; Issue: 1 Linguagem: Inglês

10.2134/agronj1980.00021962007200010009x

1435-0645

K. D. Ritchey, D. M. G. de Souza, E. Lobato, Osni Correa,

Plant nutrient uptake and metabolism

Abstract Root growth in subsoils of Oxisols is often precluded because the roots of many crops are sensitive to soil acidity. This increases plant stress during dry periods when available soil water in the limed surface layers is exhausted. The low soil CEC and high rainfall in Central Brazil suggest that soluble calcium salts might leach below the plow layer and reduce soil acidity. To test this possibility, soil columns, simulating field profiles, were constructed in the laboratory and various Ca salts were mixed in the 0 to 15‐cm layer. Addition of 1,200 mm water to 2,000 kg/ha Ca added as CaCl 2 , CaSO 4 , and CaCO 8 caused Ca movement to 180, 75, and 25 an, respectively. Calcium sulfate decreased Al saturation and increased soil pH at depth. Several field experiments were sampled to determine the effect of previous treatments on the movement of Ca + Mg. Three to four years after application of gypsum, in ordinary superphosphate, subsoil pH and Ca + Mg status were increased, and Al saturation decreased at depths as great as 75 to 90 cm. Zea mays L. roots growing in the improved subsoil environment were able to take up water and withstand droughts.