A major constraint to ruminant livestock production in many developing countries is the quantity and quality of forage available. Native grasses of the rangelands of the developing world tend to be of relatively low digestibility. The productivity of pastures can be increased through adding nitrogen and phosphorus fertilizers, adjusting the frequency and severity of grazing, and utilizing irrigation. Improving pasture quality and productivity offers a readily available means of increasing livestock production, particularly in the humid/sub-humid tropics. However, while such practices will generally improve pasture quality and animal performance, they will not always reduce GHG emissions. For example, the addition of nitrogen fertilizer in a grazing system may reduce methane emissions but increase nitrous oxide emissions.
Relationship to CSA
The sowing of better quality forages and better pasture management improves forage digestibility and nutrient quality, resulting in faster animal growth rates, higher milk production, earlier age at first calving, and increased incomes. Better nutrition can also increase fertility rates and reduce mortality rates of calves and mature animals, thus improving animal and herd performance and system resilience to climatic shocks. Substantial improvements in soil carbon sequestration and farm productivity are possible, as well as reductions in enteric emission intensities, by replacing natural vegetation with deep-rooted pastures such as Brachiaria.
Impacts and lessons learned
In Latin America, Brachiaria grasses have been widely adopted with large economic benefits; animal productivity can be increased by 5-10 times compared with animals substiting on diets of native savanna vegetation. In Brazil, where about 99 million hectares have been planted, annual benefits are about USD 4 billion. In the humid/sub-humid livestock of systems of Latin America, the total mitigation potential of improved pastures such as Brachiaria is estimated to be 44 Mt CO2 eq. This is due partially to the mitigation of methane via a reduction in the number of livestock needed to meet milk and meat demand, but mostly because of the carbon sequestration by deep-rooted grasses in the soil. Nevertheless, there are constraints to the adoption of improved pastures, mostly because of the technical capacity that is needed to manage them and the economic costs associated with sowing and maintaining them.
Rao IM, Peters M, van der Hoek R, Castro A, Subbarao G, Cadisch G, Rincón A. 2014. Tropical forage-based systems for climate-smart livestock production in Latin America. Rural21.http://www.rural21.com/uploads/media/rural2014_04-S12-15.pdf Tropical forage grasses and legumes as key components of sustainable crop-livestock systems in Latin America and the Caribbean have major implications for improving food security, alleviating poverty, restoring degraded lands and mitigating climate change. Climate-smart tropical forage crops can improve the livestock productivity of smallholder farming systems and break the cycle of poverty and resource degradation. Sustainable intensification of forage-based systems contributes to better human nutrition, increases farm incomes, raises soil carbon accumulation and reduces greenhouse gas emissions.
Thornton PK, Herrero M. 2010. The potential for reduced methane and carbon dioxide emissions from livestock and pasture management in the tropics. PNAS 107(46):19667–19672.http://dx.doi.org/10.1073/pnas.0912890107 We estimate the potential reductions in methane and carbon dioxide emissions from several livestock and pasture management options in the mixed and rangeland-based production systems in the tropics. The impacts of adoption of improved pastures, intensifying ruminant diets, changes in land-use practices, and changing breeds of large ruminants on the production of methane and carbon dioxide are calculated for two levels of adoption: complete adoption, to estimate the upper limit to reductions in these greenhouse gases (GHGs), and optimistic but plausible adoption rates taken from the literature, where these exist. Results are expressed both in GHG per ton of livestock product and in Gt CO2-eq. We estimate that the maximum mitigation potential of these options in the land-based livestock systems in the tropics amounts to approximately 7% of the global agricultural mitigation potential to 2030. Using historical adoption rates from the literature, the plausible mitigation potential of these options could contribute approximately 4% of global agricultural GHG mitigation. This could be worth on the order of $1.3 billion per year at a price of $20 per t CO2-eq. The household-level and sociocultural impacts of some of these options warrant further study, however, because livestock have multiple roles in tropical systems that often go far beyond their productive utility.
FAO. 2013a. Climate-Smart Agriculture: Sourcebook. Rome, Italy: Food and Agriculture Organization of the United Nations.http://www.fao.org/3/a-i3325e.pdf Between now and 2050, the world’s population will increase by one-third. Most of these additional 2 billion people will live in developing countries. At the same time, more people will be living in cities. If current income and consumption growth trends continue, FAO estimates that agricultural production will have to increase by 60 percent by 2050 to satisfy the expected demands for food and feed. Agriculture must therefore transform itself if it is to feed a growing global population and provide the basis for economic growth and poverty reduction. Climate change will make this task more difficult under a business-as-usual scenario, due to adverse impacts on agriculture, requiring spiralling adaptation and related costs.