|Edwards, Dwayne - UNIV OF KENTUCKY|
|Daniel, Tommy - UNIV OF ARKANSAS|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2004
Publication Date: August 1, 2004
Citation: Moore Jr, P.A., Edwards, D.R., Daniel, T.C. 2004. Long-term effects of alum-treated poultry litter on soil chemistry, nutrient runoff and crop production: is this treatment sustainable? (W.J. Chardon and G. F. Koopmans, eds) Proceedings of the 4th International Phosphorus Workshop. August 16-19, 2004. Published by Alterra. Wageningen, The Netherlands. p. 31. Technical Abstract: Research has shown that aluminum sulfate applications to poultry litter can greatly reduce phosphorus (P) runoff. However, the long-term effects of fertilizing with alum-treated litter are unknown. The objectives of this study were to evaluate the long-term effects of normal poultry litter, alum-treated litter and ammonium nitrate on soil chemistry, nutrient runoff and crop yields. A long-term (20 year) study was initiated in 1995. There were 13 treatments (unfertilized control, four rates of normal litter, four rates of alum-treated litter and four rates of ammonium nitrate) in a randomized block design. All fertilizers were broadcast applied to small plots (3.05 x 1.52m) cropped to tall fescue (Festuca arundinacea Schreb.) annually in the spring. Litter application rates were 0, 2.24, 4.49, 6.73, and 8.98 Mg/Ha (0, 1, 2, 3, and 4 tons/acre); ammonium nitrate rates were 65, 130, 195 and 260 Kg/Ha and were based on the amount of N applied with alum-treated litter. Ammonium nitrate applications resulted in reductions in soil pH beginning in year 3. This reduction in pH in soils fertilized with ammonium nitrate caused exchangeable Al values to increase from less than 1 mg Al/kg soil in year 2 to over 100 mg Al/kg soil in year 7 for many of the ammonium nitrate plots. In contrast, normal and alum-treated litter resulted in an increase in soil pH, which decreased exchangeable Al when compared to unfertilized controls. Severe yield reductions were observed with ammonium nitrate, which were due to high levels of acidity and exchangeable Al. Fescue yields were 6% higher with alum-treated litter than normal litter and 16% higher than ammonium nitrate. Phosphorus leaching was significantly greater with normal litter than alum-treated litter. These data indicate that alum-treated litter is a more sustainable fertilizer source than normal poultry litter and/or ammonium nitrate.