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 < 0.05) compared to Sabia, incorporating 801 g kg DMtotal−1, 850 g kg OMtotal−1, and between 840 and 860 g kg Ctotal−1. Gliricidia showed greater N release rate compared to Sabia and Signalgrass, with an estimated disappearance of 23, 4, and 6 mg N g DM–1 for Gliricidia, Sabia, and Signalgrass, respectively. Tree legumes showed lesser k for C:N ratio and greater for lignin concentration (P < 0.05). Gliricidia had greater release of nutrients to the soil, while Sabia had slower decomposition rates, but with the potential to form a more stable OM because of more recalcitrant compounds left behind. The k of Signalgrass was limited by the lesser N concentration and high C:N ratio in the litter, contributing to immobilization of N during litter decomposition.

中文翻译：

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林牧系统中信号草（Urochloa decumbens Stapf. R. Webster）和树栖豆科植物衰老叶片的分解

林牧系统 (SPS) 中树栖豆科植物的存在可能会影响凋落物的生产和质量，以及土壤有机质 (OM) 的特征和分布。来自两种豆科植物的衰老叶子 [Gliricidia sepium (Jacq.) Kunth ex. 沃尔普。(Gliricidia) 和含羞草 caesalpiniifolia Benth。(Sabia)] 在 SPS 与 Urochloa decumbens Stapf。在 0、4、8、16、32、64、128 和 256 天期间仍附着在植物上并在地面上孵育时，收集 R. Webster（信号草）和单一栽培的信号草牧场（Signalgrass）。响应变量包括干物质 (DM)、OM、C、N、木质素、酸性洗涤剂不溶性氮以及 C:N 和木质素:N 比率的消失。调整单个负指数模型以估计相对分解率 (k)。DM、OM、与 Sabia 相比，Gliricidia 和 Signalgrass 的 C 和 C 更大（P < 0.05），包含 801 g kg DMtotal−1、850 g kg OMtotal−1 和 840 至 860 g kg Ctotal−1。与 Sabia 和 Signalgrass 相比，Gliricidia 显示出更高的氮释放速率，估计 Gliricidia、Sabia 和 Signalgrass 的氮释放率分别为 23、4 和 6 mg N g DM-1。豆科植物的 C:N 比值 k 较小，木质素浓度 k 值较大（P < 0.05）。Gliricidia 向土壤释放更多的养分，而 Sabia 的分解速度较慢，但​​由于留下了更多顽固的化合物，因此有可能形成更稳定的 OM。Signalgrass 的 k 受到凋落物中较低的 N 浓度和较高的 C:N 比的限制，有助于在凋落物分解过程中固定 N。