Management effects on soil characteristics of two pasture types in Oklahoma

Authors: Northup, Brian; Daniel, John; Phillips, William

Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2008
Publication Date: 10/23/2008
Citation: Northup, B.K., Daniel, J.A., Phillips, W.A. 2008. Management effects on soil characteristics of two pasture types in Oklahoma [abstract]. In: Proceedings of the Soil and Water Conservation Society, Farming with Grass: Achieving Sustainable Mixed Agricultural Landscapes in Grasslands Environments, October 20-22, 2008, Oklahoma City, OK. Available on-line:http://www.swcs.org/en/publications/farming_with_grass/.

Interpretive Summary: Abstract only

Technical Abstract: Putting gain on yearling stocker cattle with forage is a significant activity in the Southern Great Plains (SGP). The use of forages in the region is likely to increase with rising fuel and feed costs, and concerns over the environmental impacts of confinement feeding. Pastures of native prairie and winter wheat are among the primary forages used for grazing stocker cattle in the SGP. These pastures are subject to numerous stressors that affect production including grazing, climate, soil fertility and farming operations. Understanding responses of soil characteristics to long-term management regimes is crucial to sustainable use of grazing lands. This study compared how different forms of pasture management, applied over 26 years (1977-2003), affect soils of upland sites in central Oklahoma. Included were graze-out of conventionally tilled winter wheat and three levels of grazing intensity (conservatively grazed over long time periods, intensively grazed over short time periods; not grazed) applied to tallgrass pastures. Soil cores were collected at 1.5 m intervals along 150 m transects in pastures under each form of management (n=101 per pasture) and divided into 3 sections (0-5 cm, 5-10 cm, and 10-25 cm depths). Soil bulk density and organic matter contents were determined and distribution maps were developed. Soils of the graze-out wheat pasture were 25% denser and contained 21% less organic matter than native prairie pastures. Management effects were largely confined to the upper 8.0 cm of the profile. Intensive forms of management produced more simplified and homogeneous distribution patterns. Such responses indicate that patch-scale processes of both wheat and native pastures change with sustained long-term management, and may ultimately affect landscape function.