EFEITOS DA SATURAÇÃO POR BASES, RELAÇÕES Ca:Mg NO SOLO E NÍVEIS DE FÓSFORO SOBRE A PRODUÇÃO DE MATERIAL SECO E NUTRIÇÃO MINERAL DO MILHO (Zea mays L.)
MUNOZ HERNANDEZ, R.J.SILVEIRA, R.I.
The experiment was carried out under greenhouse conditions in order to evaluate the effect of soil base saturation, Ca:Mg ratio and P level on the mineral nutrition and dry matter production of corn (Zea mays, L.). The soil, "Areia Quartzosa" (Quartzipsament) was collected in the 0-20 cm layer and the experiment was conducted using 3 dm3 size pots in a completely randomized 2*4*3 factorial design, with four replications, two lime adjusted soil base saturations (50 and 70%), four Ca:Mg ratios (2:1, 3:1, 4:1 or 5:1), obtained with the application of CaCO3 and MgO, and monoamonium phosphate (MAP) to provide 0, 100 or 200 mg dm-3 of P. Increases in soil base saturation influenced positively corn growth and nutrition. There was a decrease in dry matter production of tops with the increase of soil Ca:Mg ratios. The highest production was obtained with 3:1 Ca:Mg ratio and application of 100 mg dm-3 P. Increases in the concentrations of P and Mg in plant tissues with the increases in soil base saturations were observed. Increasing the Ca:Mg ratio the concentration of Mg decreased and Ca in the plants increased. The addition of P to the soil promoted significant increase in corn dry matter and improved the concentration of this element in plant tissue, but decreased the concentrations of Ca and Mg. It was concluded that soil base saturation, Ca:Mg ratios and soil phosphorus fertilization affect corn growth and mineral nutrition. The concentration in plant tissues was influenced by the availability of nutrients by plants and their balance in the soil.
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