Evaluating the decomposition of cover crop residues added to the soil allows improving the comprehension of appropriate nutrient supply for commercial crops. This study was carried out under field conditions aiming to evaluate the decomposition and nutrient release from the shoots of perennial herbaceous legumes. The treatments were green cover crops intercropped with banana: groundnut (Arachis pintoi Krapov. & W.C. Gregory.), tropical kudzu (Pueraria phaseoloides (Roxb.) Benth.), siratro (Macroptilium atropurpureum (Sessé & Moc. ex DC.) Urb.) and spontaneous vegetation (mainly Panicum maximum Jacq.). These species were cut during the dry (April 1997) and rainy seasons (January 1998). Aboveground cover crop samples were placed in litterbags, which were distributed on the plots soil surface. Dry matter decomposition and nutrient release were monitored through collection of litterbags at 5, 10, 15, 30, 60, 90, 120 and 150 days after cutting the cover crops. Dry matter decomposition of groundnut was the fastest and the spontaneous vegetation was the slowest. The decomposition constants decreased and residue half-lives increased during the dry season. There was a faster release of N, Ca and Mg in the legumes, while spontaneous vegetation presented similar results for P. Among the chemical variables under study, the cellulose and hemicellulose contents were correlated with dry matter loss. N release was correlated with C and hemicellulose contents. Results indicate the potential of perennial herbaceous legumes for nutrient release, particularly in the case of tropical kudzu and siratro.
decomposition; cover crops; plant residues
