Revista Brasileira de Milho e Sorgo (Dec 2007)
AVAILABILITY OF ZINC TO MAIZE AS AFFECTED BY Zn ADDITION AND BY SOIL pH
Abstract
Research dealing with zinc availability is meager in the soils of Southern Brazil as a result of the constant lack of response of crops to addition of this nutrient. Since soil pH affects Zn in the soil, this study aimed to evaluate the effect of lime and Zn addition on Zn availability to maize in two Brazilian soils. The experiment was carried out in a greenhouse, with four pH values (natural; 5.5; 6.0; and 6.5) and four rates of zinc (0, 10, 40, and 80 mg Zn dm-3) as treatments. Four successive maize crops were grown in two soils, without reapplication of the treatments. Zinc addition had no effect on corn dry matter regardless of soil pH, soil type and cultivation. The amount of Zn extracted from the soil by both methods (HCl 0.1 mol L-1 or Mehlich-3) increased linearly with increases on Zn applied, and it was always larger in the absence than in the presence of lime. Plant Zn concentration and Zn taken up were positively associated with Zn added and negatively related to soil pH. The pH should be considered for a better interpretation of Zn values in the soil.
