Improve Pasture or Feed Grain? Greenhouse Gas Emissions Profitability and Resource Use for Nelore Beef Cattle in Brazil’s Cerrado and Amazon Biomes

摘要

Deforested areas in Brazil’s Amazon and Cerrado savannah have historically transitioned to pasture for grazing tropical beef cattle. Brazil’s projected growth in beef exports emphasizes the importance of sustainably intensifying Brazil’s cattle industry on existing agricultural land without increasing deforestation nor accelerating land conversion. We adapted a widely used simulation model for cattle, pasture, and crops to closely match two cooperating beef farms, one in the Cerrado and one in the Amazon. We then simulated the adoption of pasture fertilization, pasture re-seeding, and pasture-based grain supplementation of cattle by a model beef farm. These three sustainable agricultural intensification strategies were compared to extensive cattle grazing, the status quo in Brazil. Beef productivity and economic returns were greater for grain supplementation, followed by pasture fertilization and pasture re-seeding. Grain supplementation had the lowest greenhouse gas emissions, with less energy and nitrogen use compared to extensive grazing, as measured as a “footprint” for every unit of beef body weight produced. Pasture re-seeding and fertilization had lower greenhouse gas footprints compared to extensive; however, water and energy use and nitrogen losses were greater. Grain supplementation used more human edible livestock feed than other strategies, so pasture intensification could increase future human food availability.