Soil nitrogen as affected by Gliricidia sepium in a silvopastoral system in Guadeloupe, French Antilles
Authors: Sierra, J.; Dulormne, M.; Desfontaines, L.
Source: Agroforestry Systems, Volume 54, Number 2, February 2002 , pp. 87-97(11)
Abstract:Knowledge of the status and dynamics of soil N is essential to improving the production and management of silvopastoral system in the tropics. Soil N status and dynamics were analyzed as key factors affecting productivity and sustainability of a cut-and-carry silvopastoral system. The total soil N and N mineralization as affected by soil moisture and temperature were studied in a Gliricidia sepium (Jacq.) Walp — Dichanthium aristatum (Poir) C.E. Hubbard grassland association and in an adjacent open grassland located in a subhumid tropical region. The plot was installed in 1989 and the pruning residues and cut grass were removed from the site. No N fertilizer was applied. Total soil N increased at an average rate of 180 kg N ha−1 in the 0–0.2 m soil layer of the silvopastoral plot. Only a third of this value could be explained by the litter, nodule and root turnover. Nitrogen mineralization in both soils varied as a function of temperature but it was not affected by soil moisture. Even if mean soil temperature was 1 °C to 2 °C greater in the open grassland, the estimated daily rate of in-situ N mineralization was 20% greater in the silvopastoral system. Our results indicated that greater N mineralization in the silvopastoral system was due to greater soil biological activity associated with higher soil organic matter rather than due to more favorable soil temperature and water conditions.
Document Type: Research Article
Affiliations: Email: firstname.lastname@example.org
Publication date: 2002-02-01