ARS | Publication request: Managing Cow-Calf Operations: Implication to Nitrogen Level in Surface and Ground Water

Submitted to: Florida Cattleman
Publication Type: Trade Journal
Publication Acceptance Date: March 23, 2010
Publication Date: May 1, 2010
Citation: Sigua, G.C., Coleman, S.W., Chase, C.C. 2010. Managing cow-calf operations: Implication to nitrogen level in surface and ground water. The Florida Cattleman and Livestock Journal. 74(8):40-44.

Technical Abstract: Despite substantial measurements using both laboratory and field techniques, little is known about the spatial and temporal variability of nitrogen dynamics across the entire landscape, especially in agricultural landscapes with cow-calf operations. Characterizing how nutrients vary across pastures is important for understanding how soil nutrients availability is controlling net primary productivity. Therefore, assessing spatial variability and distribution of nutrients in relation to land use and landscape position is critical for predicting rates of ecosystem processes and environmental stability. Further research effort on optimizing forage-based cow-calf operations to improve pasture sustainability and water quality protection therefore is still warranted. Our results indicate that current pasture management systems which include cattle rotation in terms of grazing days and current fertilizer application (inorganic + manure + urine) for bahiagrass pastures in subtropical climates on loamy sand soils offer little potential for negatively impacting the environment. Properly managed livestock operations contribute negligible loads of nitrogen to shallow groundwater and surface water. Overall, there was no buildup of soil total nitrogen in bahiagrass-based pasture. Therefore, results of this study may help to renew the focus on improving inorganic fertilizer efficiency in subtropical beef cattle systems, and maintaining a balance of nitrogen removed to nitrogen added to ensure healthy forage growth and minimize nitrogen runoff.