Submitted to: Ecological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2008
Publication Date: N/A
Interpretive Summary: Abstract only.
Technical Abstract: Pastures of native prairie and winter wheat are among the primary resources used to graze cattle in central Oklahoma. These pastures are subject to numerous stressors that affect land condition including grazing, climate, soil fertility, and farming operations. Understanding responses of soil characteristics to management is crucial to sustainable use of these resources. This study compared soil responses on an upland site in central Oklahoma (35°33’29” N, 98°1’50” W) to 26 years (1977-2003) of different forms of sustained management applied to 1.6 ha experimental paddocks. Included were grazed, conventionally tilled winter wheat, and three levels of grazing intensity (light stocking rates over long grazing periods, high stocking rates over short grazing periods, and not grazed) applied to paddocks of tallgrass prairie. Soil cores, to 0.25 m depth, were collected from each paddocks at 1.5 m intervals along 150 m transects (n=101 per paddock) situated between a ridge and toe slope. Soil cores were divided into 3 sections (0-0.05 m, 0.05-0.10 m, and 0.10-0.25 m depths)and soil bulk density and organic matter concentrations were determined. Variogram analyses defined distribution patterns, and distribution maps were developed by kriging. Soils of grazed wheat pasture were 13% denser (1.20±0.11 vs 1.06±0.03 Mg m-3) and contained 21% less organic matter (35.8±7 vs 45.6±15 g kg-1) than pastures of native prairie. Management effects were largely confined to the upper 0.10 m of soil, and intensive forms of management (wheat, high stocking rates) produced more simplified and homogeneous distribution patterns. Responses indicated that patch-scale organization of soil characteristics in wheat and native paddocks differed with long-term management, which may alter landscape function.