Soil fertility beneath the crown of tree species submitted to planting densities

The aim of this study was to evaluate the nutrient content of leaf litter and the soil beneath the crown of gliricidia (Gliricidia sepium) and sabiá (Mimosa caesalpiinifolia) under different planting densities (400, 600, 800, 1000 and 1200 plants ha-1). The experiment was carried out in a randomized block in split plot design, with three replications. The species were assigned to the plots and the densities to the subplots. Samples of litter and soil were collected three years after the trees were planted and submitted for chemical analysis. The Mg content in the litter from the gliricidia was higher than that from the sabiá. There was no difference between the species as to the other elements. The increase in planting density reduced the levels of N and Mg, but did not alter the levels of Ca and P in the litter. The nutrient content in the litter from both species presented the sequence Ca > N > Mg > K > P. There was no difference in soil fertility between soils planted with both species. An increase in density resulted in an increase in the levels of P and Mg in the soil. The contents of Na and Ca first increased and then decreased with the increase in density. The density had no effect on organic matter, K, pH or the potential acidity