Estimating animal manure and paper mill sludge nutrient credits for crop production.

摘要

The studies reported in this thesis relate to the problem of estimating the fertilizer value of manures. The N, P, and K equivalence values for nutrients derived from manure as opposed to inorganic fertilizer are estimated. No evidence was found to reject the assumed P and K availability factors of 75% and 100% respectively. No significant N residual was found at agronomic application rates. The use of cover crops in retarding N leaching is examined. Although the rye cover crop took up 2000 to 3000 lb of N/acre, it slightly decreased the corn yield in the following year. An attempt is made to quantify the N mineralization of a paper mill sludge. And finally a nutrient recordkeeping system is presented.