SOIL RESPONSES UNDER INTEGRATED CROP AND LIVESTOCK PRODUCTON

Authors: Franzluebbers, Alan; Stuedemann, John

Submitted to: Southern Conservation Tillage for Sustainable Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/27/2005
Publication Date: 6/27/2005
Citation: Franzluebbers, A.J., Stuedemann, J.A. 2005. Soil responses under integrated crop and livestock producton. In: Proceedings of the 27th Southern Conservation Tillage Conference, CD-ROM, p. 13-21. Florence, South Carolina, 27-29 June 2005.

Interpretive Summary: Rotation of pastures with crops has been a historical agricultural management practice that could become used more extensively in the future to diversify farm operations and reap agronomic and environmental benefits. Scientists with USDA-ARS in Watkinsville GA conducted a field study to determine the impact of tillage management (either plow-disk or no tillage) on soil chemical, physical, and biological properties. Following long-term pasture, organic matter was enriched at the soil surface. Plowing of pasture resulted in uniform distribution of organic matter and microbial populations, whereas chemically killing pasture and planting crops with no tillage maintained a highly stratified concentration of organic matter near the surface. High surface organic matter helped alleviate subsequent compaction from cattle that grazed cover crops. Soil strength was a function of soil water content. Higher soil water content under no tillage than under conventional tillage helped reduce the difference in soil strength that was observed between tillage systems. Both conventional- and no-tillage strategies have advantages and disadvantages for the soil in the short-term, however the balance may change due to relative importance in longer-term evaluations.

Technical Abstract: Integration of crops and livestock could be either detrimental or beneficial to soil properties, depending upon timing and intensity of animal traffic and initial condition of the soil surface. We evaluated the surface-soil properties of a Typic Kanhapludult in Georgia during the first three years of an experiment evaluating the effect of tillage [conventional (CT), conservation (NT)], cropping system (summer grain-winter cover, winter grain-summer cover), and cover crop utilization (none, grazed) variables. With initially high soil organic C (SOC) due to previous pasture management, depth distribution of SOC became widely divergent between CT and NT following cropping management. Soil bulk density during the first year was reduced with CT, but soil became reconsolidated below 12 cm, similar to that under NT. Soil penetration resistance was greater under NT than under CT, but larger differences occurred with low soil water content than with high soil water content. Although CT could alleviate negative influences on compaction with periodic tillage, NT may also have an advantage in pasture-crop rotation systems by preserving the organic matter-enriched surface soil to buffer against compactive forces.