Soil Chemistry After Fifteen Years Intensive Applications of Swine Lagoon Effluent.
Ardeshir Adeli, Dennis E. Rowe, and Karamat R. Sistani. USDA-ARS, USDA-ARS Waste Mngmnt & Forage, 810 Hwy 12 East, Mississippi State, MS 39762
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 applied to pasture and hayfields in the 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. Monitoring of soil and appropriate management are needed to mitigate the possible negative effects of salt accumulations and soil nutrient imbalances. The effects of swine 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. The accumulation and distribution of all of the soil components studied affected by annual applications of swine lagoon effluent. There was evidence of leaching of soluble salts and NO3 and thier magnitudes salt accumulation were greater in the acidic Vaiden than the alkaline Okolona soil. Leaching events possibly were associated with excess water and cracking nature of the Okolona soil. 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 greater than in the slightly alkaline soil having free calcium carbonate. It can be anticipated that long-term application of swine lagoon effluent to this agricultural soils, problems of potential pollution exists with certain constituents derived from swine effluent. Therefore, to minimize salt accumulation and nutrirnt leaching, care need to be taken in rotaing the soils receiving swine effluent for long period of time.