Herbage accumulation, nutritive value and beef cattle production on marandu palisadegrass pastures in integrated systems

Diversification of monoculture grass pastures may provide opportunity for increased productivity, efficiency, and sustainability of forage-livestock systems. Our objective was to compare herbage accumulation (HA), nutritive value, and animal performance on a grass monoculture control and two alternative systems, all based on ‘Marandu’ palisadegrass [Brachiaria (syn. Urochloa) brizantha (A. Rich.) Stapf] in the Amazon Biome. Alternatives were a crop-livestock system based on soybean [Glycine max (L.) Merr.] and palisadegrass, and a eucalyptus [Eucalyptus urograndis (hybrid of E. grandis W. Hill ex Maiden and E. urophylla S. T. Blake) clone H13]-palisadegrass silvopasture. From July 2017 to May 2018 all experimental units were stocked continuously with beef cattle using a variable stocking rate to maintain a palisadegrass canopy height of 30 cm. The grass monoculture and silvopasture systems had similar HA (13,200 kg dry matter [DM] ha−1) and herbage accumulation rate (HAR; 40 kg DM ha−1 day−1), whereas crop-livestock resulted in greater HA (127%) and HAR (158%) than the other systems. Animal weight gain ha−1 for crop-livestock was 860 kg, 15% greater than for grass monoculture and silvopasture systems (average of 750 kg). Greatest palisadegrass HA and animal performance following 2 years of soybean production support the crop-livestock as an alternative for sustainable intensification. The similar HA and gain ha−1 in the seventh year of the silvopasture and grass monoculture indicates tree-pastures systems need wider arrangements to warrant long-term productivity. The maintenance of soil fertility, appropriate grazing management, and animal nutritional supplementation can greatly improve forage-based systems in the Amazon Biome.