Submitted to: International Symposium on Phosphorus Dynamics in the Soil Plant Continuum
Publication Type: Proceedings
Publication Acceptance Date: 5/19/2006
Publication Date: 5/19/2006
Citation: Sigua, G.C., Coleman, S.W. 2006. Phosphorus management for forage-based cow-calf operations in Floria, USA: Environment and productivity. International Symposium on Phosphorus Dynamics in the Soil Plant Continuum. 3:204-205. Interpretive Summary:
Technical Abstract: Reduction of phosphorus (P) transport to receiving water bodies is now the primary focus of several studies because P has been found to be limiting nutrient for euthrophication in many Florida aquatic systems. Therefore, the way pasture management and hydrology interact to affect nutrient dynamics and water quality is an issue of increasing importance to environmentalist, ranchers, and public officials. Nutrient dynamics in various agro-animal-ecosystems are continually evolving in response to changing management practices. The objective of this study was to investigate the effects of grazing and haying on soil phosphorus dynamics (levels and changes) in subtropical beef cattle pastures with bahiagrass (Paspalum notatum) and rhizoma peanut (Arachis glabrata) with or without phosphorus fertilization in Brooksville, FL. The soil P levels across years from the fertilized fields of 119.0 + 4.9 mg kg-1 was significantly higher than those pasture fields with no P fertilization (62.8 + 7.8 mg kg-1). However, during the past 15 years, there was no P build up despite of the annual application of P-containing fertilizers in addition to the daily in-field loading of animal waste bi-products like fecals and urine. Additionally, the trophic state index (TSI) of lakes associated with long term cattle production was "good" (30-46 TSI) based upon the Florida Water Quality Standard. Hence, properly managed cow-calf operations should not be major contributors to excess loads of P in surface water.