Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2001
Publication Date: N/A
The concentration of multiple confined animal feeding operations (CAFOs) within a watershed creates increased potential for offsite movement of nutrients, pathogens, and endocrine disrupters to surface water. The objectives of this study were to assess the amount of phosphorus (P) transported out of a watershed with intensive swine production, model the P transport, and predict future P export by projecting swine production trends into the future. A 200-km**2 watershed (Tipton Creek) was selected in central Iowa where land use is dominated by corn and soybean production (84% of the land area). A total of 26 swine production facilities are currently located within the watershed. Stream sampling locations were established for collection of weekly water samples for dissolved reactive (DRP) and total (TP) phosphorus analyses. A continuous monitoring station measured discharge and collected storm event samples at the watershed outlet. The amount of P applied to cropland in the watershed was estimated at 252 metric tons (T) of fertilizer P and 132 T of manure P for a total of 384 T per year. From April 1, 2000 to April 1, 2001 concentrations of DRP and TP averaged 0.14 and 0.21 mg L**-1, respectively. Total P loss from Tipton Creek over this interval was 10.6 T or 0.52 kg P ha**-1 (2.8% of the total applied P). Arc/View-AGNPS simulations indicate that, under the current manure management system, a 5% annual increase in swine production could lead to a >30% increase in P load at the watershed outlet in 5 years.