Agronomic and environmental impacts of pasture-crop rotations intemperate North and South America

Authors: Franzluebbers, Alan; SAWCHIK, JORGE - Inia Carillanca

Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2013
Publication Date: 6/4/2014
Citation: Franzluebbers, A.J., Sawchik, J. 2014. Agronomic and environmental impacts of pasture-crop rotations intemperate North and South America. Agriculture, Ecosystems and Environment. 190:18-26.

Interpretive Summary: Agriculture has become increasingly specialized in response to political, regulatory, sociological, and economic pressures to meet market demands of an ever-larger food and fiber processing sector. However, there is a growing concern with specialized agricultural systems, because of increasingly negative environmental responses. Synergies between crop and livestock systems with the inclusion of perennial sods into crop rotations could allow tighter nutrient cycling, conservation of soil and water resources, greater reliance on renewable natural resources, inherently more functional soils, and diversity and dependability of income for farms with an abundance of labor. An ARS scientist at the Plant Science Research Unit in Raleigh North Carolina teamed with a scientist from the National Agricultural Research Institute (INIA) in Colonia Uruguay to review the scientific literature pertaining to the production and environmental responses of grass-crop rotations in the Americas. Cereal crops following perennial forages are often improved in yield potential, mostly due to the large improvement in soil organic matter that accumulates under forages. These perennial crops are also able to absorb nutrients effectively, resulting in landscapes that have less erosion, fewer water quality issues, and more diverse landscape structure. Grass-crop rotations should be considered a key component to a productive and environmentally sustainable agricultural system, but unique attributes for different agro-ecological regions need to be developed.

Technical Abstract: Agriculture has become increasingly specialized in response to political, regulatory, sociological, and economic pressures to meet market demands of an ever-larger food and fiber processing sector. However, there is a growing concern with specialized agricultural systems, because of increasingly negative responses from the environment that are manifested in: (1) water contamination with excessive nutrients, pesticides, and pathogens; (2) sinking groundwater levels due to high demand and competition from a variety of stakeholders, including specialized crop production; (3) rising greenhouse gas concentrations from soils depleted in organic matter; (4) dysfunctional soils that have become exhausted from excessive tillage, salt accumulation, and pesticide inputs; and (5) loss of family farms and rural infrastructure. Synergies between crop and livestock systems with the inclusion of perennial sods into crop rotations could allow tighter nutrient cycling, conservation of soil and water resources, greater reliance on renewable natural resources, inherently more functional soils, and diversity and dependability of income for farms with an abundance of labor. We reviewed information from North and South America on how grass-crop rotations could be a successful part of an integrated crop-livestock system approach and contribute to the sustainability of agriculture in these regions.