This work aimed to evaluate the decomposition and nutrient release of leaf litter in 8-year old Eucalyptus grandis first rotation and 2 and 5-year old regrowth systems through litter bag technique. The annual average temperature was 19.5 ºC and annual rainfall was 848 mm, with 54% of rains concentrated in the period from October to December. The results showed that the dry weight loss, nutrient release (N, K, Ca and Mg) and organic fraction release (lignin, cellulose and polyphenols) were similar for the first rotation and regrowth systems. The mass loss percentage, mean of three sites, fitted a quadratic model (y = 99.443 + 0.0348x - 0.0003x²; R²=0.92; p=0.0225). Only in the rainfall period, effective mass loss (29 - 33%), cellulose release (40 - 51%), polyphenols (54 - 74%) and low lignin release (3 - 14%) was observed. Among the nutrients, release of N (6 - 19%), K (49 -60%), Ca (18 - 20%), Mg (39 - 27 %) and immobilization of P (-20 and -40%) was observed. In northern Rio de Janeiro State, the eucalypt leaf litter decomposition dynamics showed release of K > Mg > Ca > N , over 382 days, and immobilization of P, markedly influenced by rainfall.
Nutrient cycling; cellulose; lignin; polyphenols; eucalypt
