Determination of Nitrogen Availability From Animal Manure Amended Soils

Abstract

This study was conducted to evaluate the effects of long term manure application on soil properties, winter wheat, grain yield, and to determine the N availability of land applied manure. Three different manure sources and commercial fertilizers were applied at rates of crop N or phosphorus (P) needs to a Norge loam soil. An optical sensor was utilized to determine if manure N based applications required additional N. Soil pH was maintained by N-based manure applications, but the addition of urea resulted in a decrease of approximately 0.4 pH units over time. Mehlich 3 P did not increase due to N based or P based treatments, except for poultry litter N based rate which increased by 52% in 2001 to 2003. The optical sensor did indicate that no additional N was needed. More research is needed to study the feasibility of using active sensors to manage manure nutrients.