Ciclagem de nutrientes em dois trechos de floresta estacional semidecidual na reserva florestal mata do paraíso em Vi?osa, MG, Brasil

摘要

A Semideciduous Seasonal Forest in different successional stages (initial forest and mature forest), in Vi?osa, Minas Gerais State, in the southeast region of Brazil, was studied aiming at quantifying litter annual production, decomposition, N, P, K, Ca, and Mg contents and use efficiency. The annual litter production was 6,310 kg.ha-1 for the initial forest and 8,819 kg.ha-1 for the mature forest. Nutrient annual deposition in the litter was estimated at 137 and 180 kg.ha-1 N, 5 and 8 kg.ha-1 P, 17 and 45 kg.ha-1 K, 89 and 179 kg.ha-1 Ca, 21 and 26 kg.ha-1 Mg for the initial forest and mature forest, respectively. The average forest floor biomass was 4,647 kg.ha-1 for the initial forest and 7,006 kg.ha-1 for the mature forest. The instantaneous decomposition rate (k) was estimated at 1,36 for the initial forest and 1,26 for the mature forest, with a turn over time of 270 and 288 days, respectively. The smallest litter production in the initial forest reflects the less developed structure in the site of forest in initial successional stage, with litter production of lower quality compared to the mature forest, but with faster renovation and efficient use of the nutrients.