Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2007
Publication Date: 3/1/2008
Citation: Adeli, A., Bolster, C.H., Rowe, D.E., McLaughlin, M.R., Brink, G.E. 2008. Effect of long-term swine effluent application on selected soil properties. Soil Science. 173:223-235.
Interpretive Summary: Confined swine-feeding operations generated large quantities of waste on individual farms and in warmer climate, it is typically flushed into anaerobic lagoon to facilitate digestion. To prevent lagoon overflow, swine effluent was applied to pastures and hayfields in close proximity to the lagoon from March 1 through October 31 each year at the rate of 4-5 inches per acre, threatening water quality and creating potential nutrient imbalance in soil fertility. The effects of swine (Sus scrofa domesticus) lagoon effluent on soil chemical characteristics were determined after 15 years of applications. Three soils receiving swine effluent are representative of the Blackland Prairie major land resource area initially testing very low (Vaiden) to low (Okolona and Brooksville) in Phosphorus (P). Our results indicated long-term effects of swine effluent applications on the potential build up of chemicals and salt accumulation in the slightly acidic soils were much greater than in the slightly alkaline soils having free calcium carbonate. Monitoring of site-specific soil and appropriate management are needed to mitigate the possible negative effects of salt accumulations and soil nutrient imbalances.
Technical Abstract: This study was conducted to evaluate the effects of long-term intensive swine effluent application on nutrient dynamics and chemical changes of an alkaline Okolona silty clay, an acidic Vaiden silty clay and a Brooksville silty clay loam. Three soils receiving swine effluent are representative of the Blackland Prairie major land resource area initially testing very low (Vaiden) to low (Okolona and Brooksville) in Phosphorus (P). Swine effluent has been applied to the soils under established summer forage grasses using a center-pivot or traveling gun irrigation systems at the rate of approximately 10-15 cm ha-1yr-1 since 1990. In 2006, soil samples were taken from swine effluent treated and non-treated soils, divided into the depth of 0-15, 15-30, 30-60, and 60-90 cm, air dried, ground to pass 2 mm sieve and analyzed for chemical properties. Long-term swine effluent applications resulted in increasing soil pH, electrical conductivity and soil total C in all soils. Chemical extractable soil P was much lower in the alkaline Okolona soil (60 mg kg-1) than the acidic Vaiden soil (119 mg kg-1). The potential leaching of soluble salts and NO3 in the alkaline Okolona soil was greater than in the acidic Vaiden soil possibly due to cracking nature of the alkaline Okolona soil. Water soluble P, and soil Cu and Zn concentrations were lower in the alkaline Okolona soil than in the Vaiden and Brooksville soils. Low nutrient concentrations, especially water soluble P, at the surface alkaline Okolona could be related to the presence of free CaCO3 and precipitation of soluble P with Ca which may prolong the capacity of this soil in receiving swine effluent particularly if threshold water soluble P is used as part of swine effluent management program.