Nitrogen (N) inputs to pasture systems coupled with grazing management strategies based on monitoring and control of canopy structure may provide conditions for greater productivity and enhanced forage nutritive value. This 2‐year study assessed canopy structure and nutritive value responses of three pasture treatments, namely, (1) mixed Marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R.D. Webster [syn. Urochloa brizantha Stapf]) cv. Marandu and forage peanut (Arachis pintoi Krapov. & W.C. Greg.) cv. BRS Mandobi pastures without N fertilizer (GRASS + LEGUME); (2) monoculture Marandu palisadegrass pastures fertilized with 150 kg N/ha (GRASS + N); and (3) monoculture Marandu palisadegrass without N fertilizer (GRASS). Grazing management was similar across pasture treatments, using continuous stocking and a target canopy height of 20–25 cm. Herbage mass was greater in GRASS + N and GRASS + LEGUME pastures than in GRASS in summer and spring (p = .014). The leaf:stem ratio in the grass mass (p = .731) was similar between treatments. Grass crude protein (CP) and in vitro digestible dry matter (IVDDM) were greatest in the GRASS + N pasture (p < .001). Grass neutral detergent fibre (NDF) concentration was greater at GRASS and GRASS + LEGUME pastures than in GRASS + N (p < .001). Forage peanut had a greater IVDDM and CP concentration and a lower NDF concentration than Marandu palisadegrass. Nitrogen application or the presence of the legume increased green herbage mass and improved forage nutritive value in canopies with similar height.

No abstract

The lack of nitrogen (N) input on pastures is the main limiting factor to increase animal performance in tropical regions. This 2.5‐year study assessed animal performance, forage intake and digestion, and N metabolism responses of three pasture treatments: (1) mixed Marandu palisadegrass—Brachiaria brizantha (Hochst. ex A. Rich.) R.D. Webster (syn. Urochloa brizantha Stapf cv. Marandu)—and forage peanut (Arachis pintoi Krapov. & W.C. Greg. cv. BRS Mandobi) pastures (GRASS + LEGUME), (2) monoculture Marandu palisadegrass pastures with 150 kg of N/ha (GRASS + N), and (3) monoculture Marandu palisadegrass without N fertilizer (GRASS). Continuous stocking with variable stocking rate was used with a target canopy height of 20 to 25 cm. The average daily gain was greatest at GRASS + N and GRASS + LEGUME (p = .081). GRASS + N pasture had greatest stocking rate and liveweight gain per area (p < .001 and p < .001, respectively), followed by GRASS + LEGUME pasture. No differences between treatments were found for the dry matter forage intake (p = .729); however, GRASS + N and GRASS + LEGUME pastures had greater crude protein and digestible organic matter intakes than GRASS pasture (p = .007 and p = .083, respectively). Greatest microbial protein synthesis and efficiency of microbial synthesis were found for GRASS + N and GRASS + LEGUME pastures (p = .016 and p = .067, respectively). Apparent efficiency of N utilization and microbial protein/CP intake ratio was greatest at GRASS + LEGUME pastures (p = .009 and p = .042, respectively). Nitrogen application or the integration of forage peanut in grass pasture increases animal performance, forage digestibility, and microbial protein synthesis.

Context Understanding ecology in grass–legume pastures can help support strategies aimed at maintaining canopy stability in terms of botanical composition. Aims This 2-year study evaluated spatial variability, focusing on plant structural characteristics in a Marandu palisadegrass [Urochloa brizantha (Hochst. Ex A. Rich.) R.D. Webster cv. Marandu]–forage peanut (Arachis pintoi Krapov. and W.C. Greg. cv. BRS Mandobi) mixed canopy under grazing in continuous stocking management. Methods The pasture was managed with canopy height of 20–25 cm. The experimental area had a permanent sample grid containing 50 pre-established and georeferenced plots. Principal component analysis was performed, and spatial dependence structure of the first principal component and structural variables were separately characterised by geostatistical analysis. Key results There was spatial dependence of the structural characteristics, with marked spatial heterogeneity in the distribution of all variables. Taller grass canopies caused competition for light between species, reducing legume contribution and inducing more erect forage peanut growth habit. Conversely, in areas with lower grass canopy height, forage peanut botanical composition increased to up to 70%, as it propagated more effectively by stoloniferous propagation. Conclusions The canopy structure spatial variability of a Marandu palisadegrass–forage peanut mixed pasture determines the overall average pasture grass/legume proportion. In regions with taller canopies, Marandu palisadegrass was favoured, while in areas with shorter canopy, forage peanut proportion was promoted. Satisfactory legume proportions can be reached in the canopy despite areas with reduced legume contribution. Implications Our findings using geostatistical techniques facilitate the development of useful and innovative tools allowing better comprehension for the management of mixed pastures.

No abstract

No abstract