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Context: A challenge for the livestock sector is to improve the production and nutritive value of forage grasses through sustainable management strategies. Aims: This study evaluated the impact of management on the productive and nutritive value of five pasture-based production systems: irrigated pasture with 600 kg nitrogen (N) ha−1 (IP600); rainfed pasture with 400 kg N ha−1 (RP400); rainfed pasture with 200 kg N ha−1 (RP200); silvopastoral with 200 kg N ha−1 (SP200); and degraded pasture without N fertilisation (DP0). Methods: During two experimental years, samples were collected pre- and post-grazing to determine forage and nutritional parameters. Land-saving effects and efficiencies of N fertilisation and water use were calculated. Key results: For C4 grasses, forage mass accumulation was greater for IP600 and RP400. IP600 also presented the greatest leaf area index and crude protein concentration, whereas DP0 presented the lowest values of both. For C3 grasses in the IP600 treatment, greater forage mass accumulation and leaf area index were found in winter than in autumn; all nutritional characteristics were not affected by season of the year. For land-saving effect, and N- and water-use efficiencies, IP600, RP400 and RP200 presented higher values than DP0 and SP200. Conclusions: More intensified systems with proper management allowed better productive and nutritional characteristics than degraded pasture or silvopasture, especially during seasons with greater precipitation or when irrigated. Implications: Intensification practices make better use of natural resources (water and land) and agricultural inputs (N fertiliser) to ameliorate the effects of seasonality and improve quality and productivity of tropical grasses in pasture-based livestock production systems. A challenge for livestock farmers is to improve production and nutritive value of forage grasses through management strategies. This study evaluated the impact of management on productive and nutritive traits of forages during two experimental years on five pasture-based production systems. More intensified systems with proper management allowed better characteristics than degraded pasture, ameliorating the effects of seasonality and improving tropical grasses in pasture-based livestock production systems. [ABSTRACT FROM AUTHOR]

Simple Summary: Intercropping tropical grasses with legumes has the potential to mitigate greenhouse gas emissions in livestock production systems. Here, we evaluate pigeon pea (Cajanus cajan (L.) Millsp.) intercropped with Urochloa spp. for feeding Nellore steers and compared it with a degraded and recovered pasture system during the rainy and dry seasons of the year. We found that including pigeon pea in grazing systems met the nutritional requirements of the animals to obtain higher gains, improving their performance while also reducing the intensity of enteric CH4 emissions, thus contributing to the sustainability of ruminant production based on pastures. In this study, we evaluate the effects of intercropping pigeon pea (Cajanus cajan (L.) Millsp.) with tropical pastures for feeding Nellore cattle and compared animal performance and enteric CH4 emissions with other pasture-based systems during the dry and rainy seasons of 2021. Thirty-six Nellore steers (with a body weight of 221 ± 7 kg and an age of 15–16 months) were randomly distributed in three treatments with three replicates (in paddocks of 1.5 hectares each): (1) a degraded pasture of Urochloa spp. (DEG); (2) a recovered and fertilized pasture of Urochloa spp. (REC); and (3) pigeon pea intercropped with Urochloa spp. (MIX). Enteric CH4 emissions were estimated using the sulfur hexafluoride (SF6) tracer gas technique, and dry matter intake (DMI) was determined using internal (iNDF) and external (TiO2) markers. Forages were collected by hand plucking after observations of ingestive behavior, and feces was collected after voluntary defecation. The proportion of grass and legume intake was estimated by C stable isotopes, and the forage nutritional quality was determined, while animal performance was monitored monthly, and the stocking rate was adjusted by the "put and take" technique. The results indicated that intercropping pigeon pea with tropical grasses is an interesting strategy for sustainable livestock production based on pastures. The MIX treatment was able to meet the nutritional requirements of the animals, which presented higher performance. In addition, there was a reduction in CH4 emissions up to 70% when expressed per average daily weight gain in comparison to the DEG treatment. [ABSTRACT FROM AUTHOR]

• Equations were built for tree volume and biomass in an agroforestry system (AS). • Tree volume and biomass by area depended on AS management. • Trees have potential to increase carbon sequestration in AS. • A strong relationship was observed between basal area and PAR transmission. Agroforestry systems, in which trees and crops are cultivated in rotation, succession, or association with pastures, are alternatives for the sustainable implementation of agriculture. This study estimated the productive characteristics from eight years old eucalyptus trees in different agroforestry systems and transmission of photosynthetically active solar radiation (PAR). These were composed of a pasture of palisade grass (Urochloa brizantha "BRS Piatã") and eucalyptus trees (Eucalyptus urograndis "GG100") planted in April 2011 in single rows 15 m apart with 2 m in-row spacing, totaling 333 trees ha−1. In 2016, half of the trees were thinned, and the spacing was changed to 15 × 4 m. The two systems were then evaluated using an integrated crop-livestock-forestry system (agrosilvopasture with pasture renewal, ICLF) and an integrated livestock-forest system (silvopasture with no pasture renewal, ILF). Each system had 12 paddocks of 5000 m2. In ICLF, pasture was renewed in one-third of each replication of area (two paddocks) per crop year, where the grass was simultaneously sown with corn for silage. Pasture renewal was carried out in the 2013–2014, 2014–2015, 2016–2017, and 2017–2018 growing seasons. Data were collected in April 2016 and June 2019, when 110 trees were harvested to determine wood volume and 28 to gather wood rings and samples of the canopy, roots, and carbon content. These data were used to build the equations for estimating stem volume (m3 tree−1) and tree biomass (kg tree−1). Stem diameter at breast height (DBH, 1.3 m above the ground) and tree height (H) were measured in 10% of the trees in each plot to estimate stem volume and biomass; these were compared by t -test (5%). PAR was measured continuously from 2013 to 2019 at 70 cm aboveground with linear quantum sensors at the four ICLF positions across the tree line. Using these data, equations for volume = exp[(− -10.21 + 1.68 × ln(DBH)+1.29 × ln(H)] and biomass = exp[−3.88 + 2.41*ln(DBH)+0.62 × ln(H)] were built. The stem volume was greater in ICLF (225.7 m3 ha−1) than in ILF (215.2 m3 ha−1) (p = 0.0369). The total biomass was 148.3 Mg ha−1 for ICLF and 141.0 Mg ha−1 for ILF, with no significant differences between systems. The agroforestry systems accumulated 64.5 Mg ha−1 of carbon in tree biomass by eight years after system implementation. The basal area of trees in both agroforestry systems showed a strong relationship with the transmission of PAR to the pasture. [ABSTRACT FROM AUTHOR]