Sustainable cow-calf operations and water quality: A review

As animal agriculture has evolved to larger production operations in subtropical regions of United States, the problems associated with manure handling, storage and disposal have grown significantly. Understanding the interaction effects of sustainable cow farming with water-table management, nutrient dynamics and water quality in pastures could be the key to reducing nutrients in runoff. Soils do not contribute equally to nutrient export from watersheds or have the same potential to transport nutrient to runoff nor would soil test levels accurately predict total dissolved nutrients. Better understanding of soil nutrient dynamics and crop nutrient changes resulting from different management systems should allow us to predict potential impact on adjacent surface waters. In many states, these issues are critical and of increasing importance among environmentalists, ranchers, and public officials particularly in the case of N and P. One of the first steps in assessing N or P level on any farm is to consider total N or total P inputs and outputs. In Florida, reduction of P transport to receiving water bodies is the primary focus of several studies because P has been found to be the limiting nutrient for eutrophication in many aquatic systems. Long-term monitoring of the changes in soil nutrients, especially soil P would enable us to predict soil chemical or physical deterioration under continuous forage-livestock cultivation and to adopt measures to correct them before they actually happen. Despite substantial measurements using both laboratory and field techniques, little is known about the spatial and temporal variability of nutrient dynamics across the entire landscape, especially in agricultural landscapes with cow-calf operations