Submitted to: Forage Focus
Publication Type: Popular Publication
Publication Acceptance Date: 3/11/2009
Publication Date: 3/16/2009
Citation: Jokela, W.E., Peters, J. 2009. Dairy Manure Nutrients: Variable, But Valuable. Forage Focus March, 2009. p. 3-5. Interpretive Summary:
Technical Abstract: Knowing the nutrient content of manure is essential for doing nutrient management planning for dairy farms. Summaries of over 14,000 dairy manure samples from Wisconsin and 2,300 from Vermont over a 10 to 15-year period showed average values that were consistent with UW-Extension book values but differed from those for some nutrients in the Livestock Waste Facilities Handbook. High variability, however, indicates that these average values are not reliable for nutrient management purposes, emphasizing the need for farm-specific sampling and analysis of manure to determine application rates. With high current fertilizer prices, the available nutrients in manure can be worth as much as $75 for N and over $200 for N, P, and K per acre at typical application rates for corn production. Two long-term trends were especially noteworthy. Manure content of P decreased significantly over most of the time period, presumably reflecting lowered P in dairy diets. And copper content of liquid manure in Vermont samples increased dramatically after 1998, reflecting increased use of CuSO4 foot baths and raising concerns about long-term soil loading and potentially increased plant levels.