SOIL NITROGEN POOLS UNDER BERMUDAGRASS MANAGEMENT IN THE SOUTHERN PIEDMONT USA

Authors: Franzluebbers, Alan; Stuedemann, John

Submitted to: International Nitrogen Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/14/2001
Publication Date: 10/14/2001
Citation: Franzluebbers, A.J., Stuedemann, J.A. 2001. Soil nitrogen pools under bermudagrass management in the southern piedmont usa. International Nitrogen Conference.

Interpretive Summary:

Technical Abstract: An appropriate and economic supply of N is essential for developing and maintaining the productivity of grasslands on the weathered soils of the warm, humid southeastern USA. We evaluated the factorial combination of three N fertilization sources (inorganic only, crimson clover cover crop + inorganic, and broiler litter all applied at an equivalent of 200 kg N/ha/yr) and four harvest strategies (unharvested, low and high cattle grazing pressure, and haying) on total, particulate, and potentially mineralizable soil organic N accumulation and soil inorganic N depth distribution during the first five years of 'Coastal' bermudagrass management. With cattle grazing of forage, fertilizer applications contributed to forage and animal production and 30-50% of the total N applied was subsequently stored as soil organic N. Increases in particulate organic N indicate the development of a large pool of biologically active soil organic N. Inorganic soil N was primarily limited to the surface soil where grass roots are most active with little indication of leaching beyond 1 m soil depth. Consequences of N fertilization and harvest strategies on plant and animal productivity and environmental quality will be discussed.