LITTERFALL AND NUTRIENT DEPOSITION IN A SEMI-DECIDUOS MOUNTAIN FOREST, AND IN EUCALYPTUS (Eucalyptus saligna) AND BRACATINGA (Mimosa scabrella) PLANTATIONS IN AREAS DEGRADED BY MINING

Abstract

The nutrients elements N, P, K, Ca, and Mg were quantified in a semi-deciduos mountain forest, and in eucalyptus (Eucalyptus saligna) and “bracatinga” (Mimosa scaabrella) plantations in areas degraded by mining, close to Poços de Caldas- MG (21º47’13” S - 46º34’10” W).In the eucalyptus annual litterfall was 7,100 kg.ha^-1 with 202.4 kg.ha^-1 of N, 4.4 kg.ha^-1 of P, 46.2 kg.ha^-1 of K, 440.2 kg.ha^-1 of Ca and 54.0 kg.ha^-1 of Mg. In the semi-deciduos mountain forest the annual litterfall was 4,490 kg.ha^-1 with 245.2 kg.ha^-1 of N, 10.3 kg.ha^-1 of P, 39.5 kg.ha^-1 of K, 292.8 kg.ha^-1 of Ca and 57.5 kg.ha^-1 of Mg, whereas in the “bracatinga” the annual litterfall was 3,460 kg.ha^-1 with 217.6 kg.ha^-1 of N, 11.1 kg.ha^-1 of P, 11.4 kg.ha^-1 of K, 194.1 kg.ha^-1 of Ca and 25.3 kg.ha^-1 of Mg. Therefore, the total quantity of mineral nutrients returned to the soil by litter decomposition is done according to the following sequences: Ca>N>Mg>K>P (semideciduos mountain forest andeucalyptus plantation) and N>Ca>Mg>K>P (“bracatinga”). In the litter of bracatinga was detected the smallest quantity of K, Ca and Mg, while, the higher quantity of N and P was detected in eucalyptus. The litter decomposition coefficient was higher in the bracatinga and eucalyptus. The presence of P by coming from organic matter decomposition is bigger in bracatinga plantation, N and Mg in the semi-deciduos mountain forest, and K and Ca in eucalyptus plantations. The lowest rate of P was observed in eucalyptus.