#04-031

Complete

Date Full Report Received

07/20/2006

Date Abstract Report Received

07/20/2006

Investigation

Institution:
Primary Investigator:

• Formulating diets with phytase reduces the concentration of total P in the manure compared to a conventional diet by as much as 30%. • Using DDGS in the diet results in no significant change in the concentration of total P in the manure compared to a conventional diet. • Diets formulated with either phytase or DDGS reduced the concentration of water soluble P forms in the manure compared to the conventional diet, suggesting that neither diet is expected to increase risk of P movement in runoff or leaching. • Nitrogen based manure application rates for manure from diets formulated with phytase can reducing the accumulation of P as well as the associated environmental risks from elevated soil P compared to conventional diets. • Formulating diets with phytase will allow for higher P based manure application rates than for conventional diets, thus reducing the land area required for agronomic application of manure. • Agronomic application rates for manure from diets formulated with DDGS are similar to those for manure from conventional diets without DDGS. • In a detailed incubation study, diets formulated with phytase or DDGS did not increase the degree of water soluble P. Neither phytase nor DDGS in the diet are expected to increase risk of P loss in runoff or leaching compared to conventional diets. • Phosphorus in manure from diets formulated with phytase or DDGS has similar plant availability to P from manure in a conventional diet. Plant availability of manure P was estimated from the incubation study to be an average of 85% over all experimental diets and soil types.