Intensification of livestock systems becomes essential to meet the food demand of the growing world population, but it is important to consider the environmental impact of these systems. To assess the potential of forage-based livestock systems to offset greenhouse gas (GHG) emissions, the net carbon (C) balance of four systems in the Brazilian Amazon Biome was estimated: livestock (L) with a monoculture of Marandu palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster]; livestock-forestry (LF) with palisade grass intercropped with three rows of eucalyptus at 128 trees/ha; crop-livestock (CL) with soybeans and then corn + palisade grass, rotated with livestock every two years; and crop-livestock-forestry (CLF) with CL + one row of eucalyptus at 72 trees/ha. Over the four years studied, the systems with crops (CL and CLF) produced more human-edible protein than those without them (L and LF) (3010 vs. 755 kg/ha). Methane contributed the most to total GHG emissions: a mean of 85 % for L and LF and 67 % for CL and CLF. Consequently, L and LF had greater total GHG emissions (mean of 30 Mg CO₂eq/ha/year). Over the four years, the system with the most negative net C balance (i.e., C storage) was LF when expressed per ha (-53.3 Mg CO₂eq/ha), CLF when expressed per kg of carcass (-26 kg CO₂eq/kg carcass), and LF when expressed per kg of human-edible protein (-72 kg CO₂eq/kg human-edible protein). Even the L system can store C if well managed, leading to benefits such as increased meat as well as improved soil quality. Moreover, including crops and forestry in these livestock systems enhances these benefits, emphasizing the potential of integrated systems to offset GHG emissions.

This study aimed to evaluate performance and behaviour of Nellore steers (Bos taurus indicus) in integrated systems. Treatments consisted of three different systems: livestock; crop-livestock; and livestock-forestry, with triple rows of eucalyptus trees. The experiment was carried out in Sinop, MT, Brazil, in a randomised complete block design with four replicates, during two seasons (dry-rainy transition and rainy). The experimental period was from 19 September 2015 to 10 January 2016. Nellore steers used in the experiment had an average initial weight of 344 kg ± 11 kg, in continuous stocking and variable stocking rate. Forage mass accumulation rate was evaluated and, independently of the system, had the highest values recorded during the rainy season. Microclimate was evaluated through temperature and humidity index, black globe temperature and humidity index and radiant heat load. Highest values were obtained from 11:00 a.m. to 3:00 p.m. at the dry-rainy transition period for all systems. Animal behaviour was assessed every 10 min from 7:00 a.m. to 5:00 p.m., and averages were calculated for every 2 h. The longest grazing period was recorded from 9:00 a.m. to 1:00 p.m., and then after 3:00 p.m., regardless of the system. Rumination occurred more frequently from 1:00 p.m. to 3:00 p.m. during the rainy season, and also in the shade for the livestock-forestry system. Highest weight gains per area were recorded during the rainy season and for the crop-livestock system. It is concluded that the highest yields can be achieved with the inclusion of the crop component in livestock production systems, and that Nellore steers in silvopastoral systems prefer to ruminate and stay idle in the shade.

Adoption of silvopasture is increasing, but proper design and management of pasture–tree associations is required to sustain pasture productivity. Our objective was to compare agronomic and physiological characteristics of Brachiaria brizantha (Hochst. Ex A.Rich.) Stapf. (palisade grass) cv. Marandu growing in monoculture, or in silvopasture with Eucalyptus urograndis, in the Brazilian Amazon biome. Trees were planted in triple rows (intra-row spacing 3 m, inter-row spacing 3.5 m), referred to as a grove, with three groves per 2-ha silvopasture experimental unit. Space between groves was 30 m, and tree density was 270 ha–1. From October 2015 to September 2016, all experimental units were stocked continuously with cattle by using a variable stocking rate to maintain a Marandu canopy height of 30 cm. In the silvopasture, sampling occurred at 4, 7.5 and 15 m into the non-treed area from the outer tree row in a grove. Photosynthetically active radiation (PAR) reaching the Marandu canopy averaged 21% less for silvopasture than for grass monoculture; however, forage accumulation was not different between systems, nor were Marandu stomatal conductance, water-use efficiency (WUE), transpiration rate, transpiration ratio and leaf temperature. In silvopasture, PAR and forage accumulation were 33% and 29% less, respectively, at the 4-m distance than the 15-m distance from the edge row of trees, associated with lower transpiration rate and transpiration rate and greater WUE. We conclude that Marandu palisade grass can tolerate PAR reduction in silvopasture up to ~20% without reduction in forage accumulation, supporting its potential use in agroforestry systems for cattle production in the Brazilian Amazon Biome.