Understanding the effects of N application or the introduction of a legume on N cycling is critical for achieving productive and sustainable grassland systems. This 2-year study assessed the N cycling of three pasture treatments: (1) mixed Marandu palisadegrass (Brachiaria brizantha) and forage peanut (Arachis pintoi) without N fertiliser (GRASS + LEGUME); (2) monoculture Marandu palisadegrass fertilised with 150 kg N ha⁻¹ year⁻¹ (GRASS + N); and (3) monoculture Marandu palisadegrass without N fertiliser (GRASS). Continuous stocking was used with a target canopy height of 0.20 to 0.25 m. Litter responses, forage and N intake, N livestock excretion and N cycling were measured. Existing litter and litter deposition rate were greatest in GRASS pasture (3030 and 84.3 vs. 2140 kg ha⁻¹ and 64.8 kg OM ha⁻¹ d⁻¹; average of GRASS + N and GRASS + LEGUME pastures, respectively; P < 0.10). Litter decomposition rate in GRASS pasture was smaller 30.4 and 36.0% compared to GRASS + N and GRASS + LEGUME pastures, respectively (P < 0.10). The GRASS + N obtained greatest (P < 0.10) faecal N excretion (21.7 vs. 13.8 kg N ha⁻¹ season⁻¹), and urinary N excretion (32.0 vs. 14.2 kg N ha⁻¹ season⁻¹). In the GRASS + N and GRASS + LEGUME pastures, there was a positive overall change of N in the soil–plant–animal system of 13 and 33 kg N ha⁻¹ year⁻¹, respectively. In the GRASS pasture, there was an overall negative change of N in the soil–plant–animal system of − 41 kg N ha⁻¹ year⁻¹. Nitrogen application or the integration of forage peanut in a grass pasture increased the conservation of soil N reserves.

了解施氮或引入豆科植物对氮循环的影响对于实现高效和可持续的草地系统至关重要。这项为期 2 年的研究评估了三种牧草处理的氮循环：(1) 混合马兰杜 (Marandu palisadegrass) ( Brachiaria brizantha ) 和饲料花生 ( Arachis pintoi ) 不施氮肥 (GRASS + LEGUME)；(2) 150 kg N ha ^-1 年^-1施肥的单一栽培 Marandu palisadegrass(草 + N); (3) 不施氮肥的单一栽培马兰杜栅栏(GRASS)。使用连续放养，目标树冠高度为 0.20 至 0.25 m。测量了垫料响应、草料和氮摄入量、牲畜氮排泄量和氮循环。现有凋落物和凋落物沉积率在 GRASS 牧场中最大（3030 和 84.3 与 2140 kg ha ^-1和 64.8 kg OM ha ^-1 d ^-1；分别为 GRASS + N 和 GRASS + LEGUME 牧场的平均值；P  < 0.10） . 与 GRASS + N 和 GRASS + LEGUME 牧场相比，GRASS 牧场的凋落物分解率分别小 30.4% 和 36.0%（P  < 0.10）。GRASS + N 获得最大 ( P  < 0.10) 粪便 N 排泄（21.7 与 13.8 kg N ha^-1季^-1）和尿中氮排泄（32.0 与 14.2 kg N ha ^-1季^-1）。在 GRASS + N 和 GRASS + LEGUME 牧场中，土壤-植物-动物系统中 N 的总体变化分别为 13 kg N ha ^-1 年^-1和 33 kg N ha ^-1。在 GRASS 牧场中，土壤-植物-动物系统中 N 的总体负变化为 - 41 kg N ha ^-1 年^-1。在草场施氮或掺入饲料花生增加了土壤氮储量的保持。