Decomposition of senescent leaves of signalgrass (Urochloa decumbens Stapf. R. Webster) and arboreal legumes in silvopastoral systems

The presence of arboreal legumes in silvopastoral systems (SPS) may affect litter production and quality, and the characteristics and distribution of soil organic matter (OM). Senescent leaves from two tree legumes [ Gliricidia sepium (Jacq.) Kunth ex. Walp. (Gliricidia) and Mimosa caesalpiniifolia Benth. (Sabia)] in SPS with Urochloa decumbens Stapf. R. Webster (signalgrass), and from signalgrass pasture in monoculture (Signalgrass), were collected when still attached to the plant and incubated on the ground during 0, 4, 8, 16, 32, 64, 128, and 256 days. Response variables included the disappearance of dry matter (DM), OM, C, N, lignin, acid detergent insoluble nitrogen, and C:N and lignin:N ratio. Single negative exponential models were adjusted to estimate the relative decomposition rate ( k ). The decomposition rate ( k ) of DM, OM, and C was greater for Gliricidia and Signalgrass ( P