Water Resources Research Act Program

Details for Project ID 2007AR162B

Long-term runoff water quality in response to natural rainfall as affected by poultry litter application rate

Institute: Arkansas
Year Established: 2007 Start Date: 2007-03-01 End Date: 2008-12-31
Total Federal Funds: $18,519 Total Non-Federal Funds: $37,043

Principal Investigators: Kristofor Brye

Project Summary: Agriculture and the economies of the Ozark Highlands, (i.e., northwest Arkansas and northeast Oklahoma), and other regions throughout the southern United States, are largely influenced by the poultry industry. Consequently, animal waste disposal and, ultimately, surface and groundwater quality become major issues in areas with a large concentration of confined-animal-feeding operations. Poultry litter contains notable amounts of plant nutrients and heavy metals. Despite the cost-effective use of poultry litter as an organic nitrogen and phosphorous fertilizer, the potential impairment of surface and groundwater from soluble nutrients and metals, particularly arsenic (As), chromium (Cr), cadmium (Cd) and selenium (Se), contained in poultry litter is an important concern to those requiring clean drinking water supplies. Much research has been conducted on runoff water quality as affected by poultry litter application rate in response to rainfall simulation. Rainfall simulations generally produce rainfall equivalent to a 5- to 10-year storm event and represent worst-case scenarios. However, little information exists on runoff water quality as affected by poultry litter application rate in response to natural rainfall. Therefore, to sustain high quality soil and water resources in northwest Arkansas and northeast Oklahoma, runoff water quality as affected by poultry litter application rate in response to natural rainfall need to be studied. The objective of this research proposal is to continuously monitor runoff and solute losses in runoff, specifically soluble metals (i.e., As, Cd, Cr, Cu, Fe, Mn, Ni, Se, and Zn) and plant nutrients (Ca, Mg, Na, K, P, NH4-N, NO3-N), from tall fescue pasture soil amended with varying rates of poultry litter. It is hypothesized that runoff losses of soluble litter-contained constituents are highly temporally dynamic, varying significantly by season and year, and are correlated to litter application timing and actual storm events, but are not necessarily proportionate to litter application rate. More specifically, in areas with long history of litter application and resulting high soil-test-P levels, simply reducing litter applications or ceasing them altogether will not result in a proportionate decrease in runoff losses of soluble litter-contained constituents such as metals and some plant nutrients. Four years of continuous data have already been collected and processed, but not summarized and statistically analyzed, from a well-established research study. By the end of this 1-year study cycle, over five years of continuous runoff and solute runoff loss data in response to natural precipitation will have been accumulated. This data set will allow for the assessment of inter-seasonal and inter-annual variations in runoff losses in response to natural precipitation, something not possible from even repeated rainfall simulation studies over a similar time period. This data set will also provide a means of determining more representative flow-weighted mean concentrations and runoff losses over a multiple-year period with varying precipitation patterns and amounts.