Trends in Dry Matter Yield Following Differential Broiler Litter Application from a Soil Enriched with Organic Matter and Phosphorus

Abstract

Broiler litter is often applied to pastures as an organic fertilizer. A history of repeated annual litter application can increase soil-test P concentrations to levels that can result in degraded water quality if P-enriched sediment enters waterways after being transported from areas prone to erosion. Nutrient management tools, such as the P Index, are being used in many areas of concentrated broiler production as a means to limit the amount of P added to soil in litter applications. However, it is unclear how soon forage producers may need to begin using inorganic fertilizers to supply nutrients to meet target yields if P-based nutrient management plans indicate that litter application should cease. The main objective of this study was to evaluate annual dry matter (DM) yield trends for broiler litter application rates of 0, 2.5, and 5 tons/acre over a 6-year period for a site that had high near-surface, soil-test P and enriched soil organic matter from a history of litter application. Results demonstrate that DM yields were maintain at an average of 2.7 tons/acre for 6 years following the cessation of litter application without decline. We conclude that the use of costly inorganic fertilizers can be delayed for several years because the release of N via decomposition of litter-enriched soil organic matter is likely adequate to maintain modest DM yields.