Silvopasture systems using tree legumes have potential to reduce C footprint of livestock systems in the tropics. This 4-year study evaluated productive responses of signal grass ( Brachiaria decumbens Stapf.) and the performance of cattle in silvopastoral systems (SPS) in the sub-humid tropical region of Brazil. The experimental design was randomized complete block with three replications. Treatments were: signal grass + Mimosa caesalpiniifolia Benth.; signal grass + Gliricidia sepium (Jacq.); and signal grass monoculture. Cattle were managed under continuous stocking with variable stocking rate. Herbage mass (HM) was greater on signal grass monoculture (5057 kg DM/ha) than in mixed pastures (3292 kg DM/ha, average). There was interaction ( P < 0.05) between treatment × evaluation month for HM, and the greatest value was observed in May (2722 kg DM/ha). Herbage allowance varied from 1.29 to 3.07 kg DM per kg of body weight (BW). Herbage accumulation rate varied throughout the evaluations, with the greatest rate observed in July (56 kg DM/ha per day) and the lowest in December (15 kg DM/ha per day). Average daily gain was similar across systems (0.65 kg day −1 ), varying according to month. Stocking rate ranged from 1.5 animal units (AU; equivalent of a 450-kg animal) per ha in December (dry season) to 2.2 AU/ha in July (rainy season). Animal performance per area tended to decrease in the SPS (411 kg BW ha −1 year −1 ) when compared with signal grass in monoculture (508 kg BW ha −1 year −1 ), especially in the Mimosa system. Adding tree legumes reduced animal performance per area due to competition between arboreal and herbaceous components, especially in the Mimosa system that had a more closed canopy.

中文翻译：

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使用豆科植物在单一草种或林场中的动物表现

使用豆科植物的森林牧场系统有可能减少热带地区牲畜系统的碳足迹。这项为期 4 年的研究评估了信号草 (Brachiaria decumbens Stapf.) 的生产反应以及巴西亚湿润热带地区林牧系统 (SPS) 中牛的生产性能。实验设计是随机完整区组，重复三次。处理为：信号草 + Mimosa caesalpiniifolia Benth。信号草 + Gliricidia sepium (Jacq.); 和信号草单一栽培。牛在连续放养下管理，放养率可变。信号草单一栽培（5057 kg DM/ha）的牧草质量（HM）大于混合牧场（3292 kg DM/ha，平均）。HM的治疗×评估月份之间存在交互作用（ P < 0.05），最高值出现在 5 月（2722 kg DM/ha）。牧草允许量从每公斤体重 (BW) 1.29 至 3.07 kg DM 不等。在整个评估过程中，牧草积累率各不相同，7 月份观察到的最大速率（每天 56 公斤干物质/公顷）和 12 月份最低（每天 15 公斤干物质/公顷）。不同系统的平均日增重相似（0.65 kg day -1 ），随月而异。放养率从 12 月（旱季）的每公顷 1.5 个动物单位（AU；相当于 450 公斤的动物）到 7 月（雨季）的 2.2 AU/公顷不等。与单一栽培的信号草（508 kg BW ha -1 year -1 ）相比，SPS（411 kg BW ha -1 year -1 ）的单位面积动物性能趋于降低，尤其是在含羞草系统中。