Submitted to: Proceedings Annual Conference US Composting Council
Publication Type: Proceedings
Publication Acceptance Date: December 25, 2002
Publication Date: December 29, 2002
Interpretive Summary: Guidelines to control the available P added to soils are being discussed in many states. Phosphorus has been associated with algal blooms in surface waters. Nitrogen had been the concern for several years because there is a drinking water standard for nitrate. Now research is focusing on P content of amendments to soils, especially manures and composts in regions where animal production is concentrated. A study was conducted to compare poultry litter compost to triple super phosphate, a common commercial fertilizer. The data showed that poultry litter compost was equal to triple super phosphate. Farmers can substitute poultry litter compost for triple super phosphate simply by having a total P analysis conducted on the compost and applying according to the phosphorus needs of the crop. Farmers can comply with nutrient management plans using a one-for-one poultry litter compost for triple super phosphate substitution.
Technical Abstract: Application of manures and composts to soils should follow recommended nutrient management plans so that nutrients in excess of plant needs are avoided. Recently, levels of P in agricultural soils have been investigated closely because inputs of P are out of line with outputs. Accumulation of P in soils has been steadily increasing. The P fertilizer value of poultry litter compost (PLC) has not been thoroughly investigated. Studies were conducted to compare triple super phosphate to PLC in a pot study using fescue and Sassafras soil. Phosphorus availability of PLC was equal to TSP. Data suggested that PLC-P may be more available than TSP-P when N becoming limiting, but addition of N after the second harvest did indicate that PLC-P was not greater than but equal to TSP. Numerous factors associated with soil chemistry of compost P availability including biological activity, metal content and pH may have influenced the results.