NUTRIENT CONTENT OF DAIRY MANURE FROM 3 HANDLING SYSTEMS

Animal manure is often used as a source of crop nutrients. Unfortunate ly the nutrient content of manure is quite variable, The objectives of this study were to: (i) evaluate the nutrient content of dairy manure from different handling systems and determine if published nutrient c redits are outdated, (ii) determine if the nutrient content could be e stimated from the solid content of the manure, and (iii) determine the seasonal variation of the nutrient content of manure. Three dairy-man ure handling systems, dairy feedlots, dairy barn cleaners, and dairy b edded packs, were sampled sequentially from June 1990 to April 1992. M anure was sampled by handling system at 13 farms located in northeaste rn Iowa. Samples were analyzed for total Kjeldahl N (TKN), ammonium-N, P2O, K2O, and solid content. The nutrient values found in this study were higher than values previously reported in Iowa and other midwest states. For dairy feedlot manure, solid content of the manure was corr elated with the nutrient content of the manure. A correlation between solid content and nutrient content was not evident for dairy barn clea ner manure or dairy bedded pack manure. Dairy feedlot manure nutrient values were higher in summer and fall than in spring and winter. Seaso nal variation was not evident for the dairy bedded pack manure or the dairy barn cleaner manure. The use of manure in a nutrient management program is dependent on accurate nutrient recommendations based on tho rough and timely manure sampling.