Acidic Brazilian soils presenting toxic aluminum levels, plus low essential elements availability, specially phosphorus, demand limestone and fertilizers application for adequate agricultural use. The effect of four limestone rates, based on soil Al3+ concentrations and five Ca:Mg ratios on the shoot dry matter yield and mineral composition of two alfalfa cultivars (Florida 77 and Crioula), cultivated in an alic Red-Yellow Latosol, clayish texture was evaluated, under greenhouse conditions. A factorial scheme in a completely randomized design with four repetitions was used. The shoot dry matter yield of both cultivars increased with the rates of limestone, but only the cultivar Florida 77 showed significant differences among Ca:Mg ratios. Concentrations of Ca, Mg and N in the shoots dry matter, in general, increased in response to applied limestone, but only the Ca and Mg altered by the different Ca:Mg ratios. Values for P and K, showed small decreases with the increase in limestone rates, although still satisfactory for alfalfa nutrition.
Medicago sativa; liming; nutrients; dry matter content; soil fertility
