ARS | Publication request: Runoff and sediment responses to grazing native and introduced species on highly erodible Southern Great Plains soil.

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 7, 2012
Publication Date: June 27, 2012
Citation: Wine, M., Zou, C., Bradford, J.A., Gunter, S.A. 2012. Runoff and sediment responses to grazing native and introduced species on highly erodible Southern Great Plains soil. Journal of Hydrology. 450-451:336-341.

Interpretive Summary: The Rolling Red Plains of western Oklahoma have highly erodible soils that are subject to rapid erosion under inappropriate management. Understanding the hydrologic effects of different land uses is critical for managing this landscape. Runoff and sediment discharge were measured for four adjacent field-scale watersheds located on the USDA-ARS Southern Plains Range Research Station in Woodward, Oklahoma from 1977 to 2005. For the duration of the study, the Control watershed remained in native mixed-grass prairie and had no grazing or moderate grazing during the growing season. Treatments in the non-Control watersheds included: short-duration grazing, double cropping of wheat and pearl millet with no tillage, grazing Yellow bluestem [Bothriochloa ischaemum (L.) Keng. var. ischaemum (Hack.) Celarier and Harlan], conventional tillage, minimum tillage, heavy grazing of native perennial grasses, and no-till wheat production. All treatments significantly increased runoff, sediment discharge, or both relative to the mixed-grass prairie Control watershed. In this water-limited system of Northwest Oklahoma, the mixed-grass prairie watershed never lost more than 5% of precipitation as runoff. In contrast, tilled, no-till, and grazing Yellow bluestem treatments lost more precipitation as runoff in some years than the Control watershed. This water loss occurred despite consistently higher biomass production and leaf litter cover with the grazing of Yellow bluestem. Increases in runoff were usually associated with an increase in runoff events as well as greater peak runoff rates. Treatments that involved grazing annual crops such as wheat (Triticum aestivum), pearl millet (Pennisetum glaucum), and oats (Avena sativa) resulted in the lowest leaf litter cover and the greatest annual sediment discharge carried by precipitation runoff.

Technical Abstract: The Rolling Red Plains of western Oklahoma have highly erodible soils that are subject to rapid erosion under inappropriate land use. Understanding the hydrologic effects of different land uses is pivotal for managing this landscape to minimize runoff and sediment discharge and to improve stream-water quality, site productivity, and agricultural sustainability. Runoff and sediment discharge were measured for four adjacent catchments located at the USDA-ARS Southern Plains Range Research Station in Woodward, Oklahoma from 1977 to 2005. For the duration of the study, the Control catchment remained in native mixed-grass prairie and annually experienced either no grazing or moderate grazing. Paired watershed analysis was used to uncover the hydrologic effects of treatments, which included: short duration grazing, double cropping of wheat and pearl millet with no tillage, grazing Yellow bluestem [Bothriochloa ischaemum (L.) Keng. var. ischaemum (Hack.) Celarier and Harlan], conventional tillage, minimum tillage, heavy grazing of native perennial grasses, and no-tillage wheat culture. Each treatment catchment experienced a calibration period in which its vegetation was native grass species. All treatments significantly increased runoff, sediment discharge, or both relative to the mixed-grass prairie control. In this water-limited system, the mixed-grass prairie catchment never lost more than 5% of precipitation as runoff. In contrast, tilled, no-till, and grazing Yellow bluestem treatments lost more than 5% of precipitation as runoff in some years. This loss occurred despite consistently higher biomass production and leaf litter cover associated with the grazing Yellow bluestem. Increases in runoff were usually associated with an increase in the number of runoff events as well as in the peak discharge rate. Treatments that involved grazing annual crops such as wheat (Triticum aestivum), pearl millet (Pennisetum glaucum), and oats (Avena sativa) resulted in the lowest leaf litter cover and the greatest annual sediment discharge.