Arboreal Legume Litter Nutrient Contribution to a Tropical Silvopasture
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2016 by the American Society of Agronomy. Legumes contribute to pasture sustainability through symbiotic N2 fixation, which may increase primary productivity and animal performance in low-input systems. Litterfall is the main way of cycling nutrients from tree legumes. We quantified gliricidia [Gliricidia sepium (Jacq.) Kunth ex Walp.] and sabi (Mimosa caesalpiniifolia Benth) litter deposition, along two 336-d cycles, in a signalgrass (Brachiaria decumbens Stapf.) pasture. Litterfall was produced throughout the year but concentrated in the dry season. Sabi produced slightly greater (P < 0.0001) litterfall amounts in the two cycles (10,790 kg ha1) than gliricidia (10,420 kg ha1) but the overall average N concentration of gliricidia (21.5 g kg1) was greater than that of sabi (18.8 g kg1). Nitrogen amounts cycled through the litter were greater for gliricidia in both cycles (105 and 109 kg N ha1) than for sabi (87 and 98 kg N ha1). The proportions of litter N that were derived from the atmosphere by symbiotic fixation were similar (P 0.05) in both species (55%) and varied little along the two cycles. Lignin concentration, which influences decomposition, was similar in both species, averaging 238 and 214 g kg1 in the two cycles for gliricidia and 233 and 246 g kg1 for sabi. Greater N concentration, lower C/N ratio and lower lignin concentration indicate that gliricidia litter may have a faster cycling rate than sabi litter. Sabi could be a more promising species for soil cover and protection because of its slower litter decomposition rate.
author list (cited authors)
Oliveira Apolinrio, V. X., Dubeux, J., Andrade Lira, M., Sampaio, E., Amorim, S. O., Miranda e Silva, N. G., & Muir, J. P.
complete list of authors
Oliveira Apolinário, Valéria Xavier||Dubeux, José Carlos Batista||Andrade Lira, Mário||Sampaio, Everardo VSB||Amorim, Silvânia Oliveira||Miranda e Silva, Nalígia Gomes||Muir, James P