SOIL ORGANIC MATTER AND NUTRIENT CYCLING TO SUSTAIN AGRICULTURE IN THE SOUTHEASTERN USA
Location: Athens, Georgia
Title: Opportunities and challenges for integrating North American crop and livestock systems
Submitted to: CABI(Council of Applied Biology International, Oxford, United Kingdom
Publication Type: Book / Chapter
Publication Acceptance Date: December 28, 2010
Publication Date: December 7, 2011
Citation: Franzluebbers, A.J., Sulc, M.R., Russelle, M.P. 2011. Opportunities and challenges for integrating North American crop and livestock systems. In: Lemaire, G., Hodgson, J., Chabbi, A., editors. Grassland Productivity and Ecosystems Services. Oxford, UK: CABI(Council of Applied Biology International).p. 208-218.
Interpretive Summary: Agriculture in developed countries like the USA has become increasingly specialized in response to political and economic pressures to meet market demands of an ever-larger food and fiber
processing sector. Conservation agricultural systems that integrate crops and livestock could provide opportunities to vigorously capture ecological interactions to make agricultural
ecosystems more efficient at cycling of nutrients, rely more on renewable natural resources, and improve the inherent functioning of soils, while achieving acceptable or improved economic
returns for the farmer. Scientists from the USDA Agricultural Research Service in Watkinsville Georgia and St. Paul Minnesota collaborated with a scientist at the Ohio State University to
describe the opportunities and challenges for integrating North American crop and livestock systems in a book focused on grassland productivity and ecosystem services. The book chapter describes the need to renew the potential paths toward sustainable and integrated agricultural systems. Examples of integrated crop/ livestock systems are briefly outlined, including sodbased
rotations, grazing of cover crops, integrated crop/livestock/ woodlands, replacement of bare fallow with forages, winter grazing of wheat, and replacement of intensively irrigated monoculture crops with a diversity of dryland crops and rangeland. A transformation of agriculture in North America is needed to increase production, mitigate past environmental damage, protect biological diversity, reduce dependence on fossil fuels, provide healthier foods, and increase economic and cultural opportunities in rural America. Greater integration of crops and livestock offers a substantial contribution towards meeting the goals of
sustainability in agriculture.
Grasslands in North America offer abundant opportunities to support ruminant animal production systems, both in the arid western states and the mesic eastern states. Integration of crops and livestock was a common practice in North America prior to the widespread adoption of inorganic fertilizer application and chemical pest control methods. Synergies between crop and livestock systems allow tighter nutrient cycling, conservation of soil and water resources, and diversity and dependability of income for farms with an abundance of labor. In contrast, contemporary farming systems in the USA typically are specialized operations that keep food costs to consumers as low as possible, increase the size of operations to take advantage of the economy of scale, and compete in global markets. However, specialization has had unintended consequences due to poor mechanisms to control nutrient loading and pathogen dispersal on specialized livestock farms, reliance on pesticides and fertilizers on specialized crop farms that threaten water quality, and loss of family farms and rural infrastructure. A growing realization of the negative impacts of specialization has resulted in a movement to re-integrate crop and livestock systems, of which some systems can be characterized by key management approaches, such as grazing cattle on winter cover crops, diversifying farms with both crops and grasslands to reduce irrigation water usage, and rotating crops with pastures using no-tillage management to avoid soil loss and reduce external inputs through biological synergies. This chapter describes issues of sustainability and development of recent farm practices to address opportunities to capture soil carbon sequestration benefits, overcome water limitations, reduce water pollution, and diversify and invigorate rural communities with integrated crop-livestock systems in North America.