Production of beef cattle grazing on Brachiaria brizantha (Marandu grass)—Arachis pintoi (forage peanut cv. Belomonte) mixtures exceeded that on grass monocultures fertilized with 120 kg N/ha

Abstract

Mixed grass/legume pastures are an alternative to grass monocultures for increased beef cattle production in tropical climates. The objective of this study was to evaluate the productivity of beef cattle grazing either a mixed pasture of Brachiaria brizantha cv. Marandu grass and Arachis pintoi (forage peanut) cv. Belomonte or a Marandu monoculture, under rotational stocking. Five trials were conducted over a period of nine years in north-eastern Brazil where the sward structure (forage, grass and legume mass) and animal performance were compared for a mixed Marandu grass/ forage peanut pasture, and a Marandu grass monoculture with 120 kg N ha −1 y −1 .Stocking rate was adjusted to maintain forage allowance at 4% body weight/day. A block design was used with four replicates, and warm and cool seasons within each trial were considered, using repeated measurements over time. In the warm season, the forage mass in the mixed pastures was 17% greater than in the monoculture (p = .049), and the stocking rate, average daily gain and liveweight gain per ha were 16.4%, 20.0% and 28.7% greater (p = .004, p < .001 and p < .001 respectively). The average daily gain showed a positive linear relationship with the legume proportion in the sward (p < .001). The mixed forage peanut/Marandu pasture sustained significantly greater beef cattle production (789 kg ha −1 y −1 ) compared to the N-fertilized grass monoculture (655 kg ha −1 y −1 ). Appropriately managed, mixed pastures of forage peanut/Brachiaria pastures are sustainable and have high potential for use in the humid tropics. K E Y W O R D SArachis pintoi, beef cattle, Brachiaria, fertilized pasture, mixed pasture, warm-season legume

Palisadegrass pastures with or without nitrogen or mixed with forage peanut grazed to a similar target canopy height. 1. Effects on herbage mass, canopy structure and forage nutritive value

“…In the last 20 years, the average price of N fertilizer has increased by more than 500% on the Brazilian market (ANDA, 2015). An attractive alternative would be the establishment of a forage legume in the sward to provide N (Muir et al., ,,,2011, 2014; Pereira et al., 2020), which along with other benefits would minimize dependence of farmers on synthetic N fertilizer (Alencar et al., 2018). Biological nitrogen fixation (BNF) is extremely relevant to sustainable agriculture (Oldroyd et al., 2011; Udvardi & Poole, 2013) since it represents the primary N input for several terrestrial ecosystems (Carvalho et al., 2019).…”

Could forage peanut in low proportion replace N fertilizer in livestock systems?

“…In Northwest Brazil, drought stress reduced forage peanut biomass in a mixed system [17]. On the other hand, in Northeast Brazil, there was no negative impact of the dry season on forage peanut growth [44]. The authors suggested positive legume performance due to the favorable weather in the study region, even during the dry season.…”

Forage legumes in grass pastures in tropical Brazil and likely impacts on greenhouse gas emissions: A review

“…It may be that the range of 20% to 45% legume in the diet suggested as ideal for tropical forage legumes by Thomas (1995) is low for this species of high digestibility and low fibre content (Gomes et al., 2018). It seems safe to conclude that at a forage allowance of 4% of BW day −1 or less (a mean of 3.2% of BW day −1 was achieved in the study of Pereira et al., 2020) or sward height at the start of grazing of 24 to 30 cm, such mixed pastures can maintain high animal productivity per ha over many years with no necessity to replant or to restrict grazing to allow seed production.…”

“…In Brazil, the only long‐term experiment (9 years) with forage peanut in mixed pastures is that of Pereira and de Rezende (2020) conducted at the CEPLAC pasture station (Itabela, south Bahia State) in the Atlantic forest biome. Here, the climate is warm and with year‐round rainfall but a far lower precipitation (annual mean 1,300 mm) than in the Atlantic Zone of Costa Rica and a much less fertile soil.…”

“…The same grazing strategy as adopted by Pereira et al. (2020) was used, with stocking rate adjusted to maintain a forage allowance at 4% of body weight day −1 . In this case, fertilization with P and K for all pastures was considerably higher than in the previous B. humidicola/D.…”