Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2007
Publication Date: 3/1/2008
Citation: Adeli, A., Bolster, C.H., Rowe, D.E., McLaughlin, M.R., Brink, G.E. 2008. Effects of long-term swine effluent application on selected soil properties. Soil Science. 173:223-235. Interpretive Summary: Improving swine effluent management practices requires an understanding of the fate of nutrients derived from swine effluent and their effects on soil quality parameters. In the southeastern U.S., swine effluent is generally applied to surrounding crop lands and not only provides a method of manure disposal but also provides nutrients for crop growth. The effectiveness of soil-plant systems to assimilate swine effluent derived nutrients depends on the chemical, physical, and biological attributes of the soil. Application of swine effluent to the soil improves soil fertility by increasing plant availability of macro and micro nutrients in the zone of application. Although the effects of solid and liquid animal manures on soil properties have been well documented, swine effluent is very low in suspended solids and organic C. Therefore, long-term application of swine effluent may affect soil chemical properties differently than solid or liquid animal manures. Measurements of soil property indicators from long-term swine effluent application is needed to evaluate the capacity of soils in receiving animal waste without adverse impact on the environment and soil quality as well.
Technical Abstract: This study was conducted to determine the effects of long-term swine lagoon effluent application on nutrient distribution in an alkaline Okolona silty clay, an acidic Vaiden silty clay, and a Brooksville silty clay loam. Swine effluent has been applied using a center-pivot irrigation system at a total rate ranging from 4 to 6 inches of effluent per year since 1990. In October 2005, soil samples were taken from the irrigated and non-irrigated sites at the following depths: 0-5, 5-15, 15-30, 30-60, and 60-90 cm. Soils were air-dried, ground to pass 2 mm sieve, and analyzed for selected chemical properties. Sorption isotherms were also performed on the soil samples to determine P sorption capacity and strength. Long-term application of swine effluent resulted in decrease in soil pH and increase in soil electrical conductivity (EC) in all three soils. Total soil carbon (TC) and microbial biomass C increased in irrigated sites for all soils. Soil ammonium (NH4-N), nitrate (NO3-N), Mehlich 3 extractable P, water soluble P, and zinc (Zn) concentrations were elevated at the 0-5 cm and 5-15 cm depths and their values were extremely lower in the alkaline Okolona soil than in the Brooksville and Vaiden soils. No clear effect was observed for P sorption strength and capacity. Low N and P accumulation in alkaline Okolona soil may prolong the capacity of this soil in receiving swine effluent particularly if threshold soil test P level is used as part of swine effluent management program.