Monday, November 13, 2006

Soil Profile Nutrient Distribution Following 10 Years of Poultry Litter Application in Conventional and Conservation Tillage Systems.

Harry Schomberg, Dinku Endale, Michael Jenkins, and Ronald Sharpe. USDA-ARS, 1420 Experiment Station Rd., Watkinsville, GA 30677-2373

The distribution of pH, P, K, Ca, Mg, Mn and Zn within the soil profile was determined following 10 years of poultry litter application to a Cecil sandy loam soil in the Southern Piedmont.  During the 10 year period, 95 Mg ha-1 of poultry litter was applied to five cotton crops and five corn crops. Changes in nutrient contents were confined primarily to the top 30 cm. The greatest movement of nutrients was observed for K where the 0 to 45 cm profile K content increased from an average of 150 to 350 kg ha-1 and was not different between the two tillage systems.  The amount of Mehlich-I P in the 0 to 15 cm depth increased similarly for both tillage systems from 75 to 300 kg ha-1. Some increase in P below the 15 cm depth was observed for the NT system but the amount was not significant. Increases in the amounts of Ca, Mn, and Zn were also noted for the surface depth but not for deeper depths. Only small changes in the amount of Mg were noted during the 10 year period.