| 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. |
