Calibration and Uniformity of Solid Manure Spreaders

Introduction ield experience and research demonstrate that manure nutrients can be readily substituted for commercial fertilizer. Fertilizer needs depend on soil test levels. Substituting manure at a lower cost than commercial fertilizer can result in signifi cant savings if relatively uniform application and distribution can be maintained. The less nutrient-dense manure requires more hauling of material to the fi eld. To take full advantage of fertilizer in manure, correct application rates and uniform application are important issues. Typical nitrogen (N), phosphorous (P), and potassium (K) contained in different manure sources are detailed in Iowa State University Extension publication, Managing Manure Nutrients for Crop Production (PM 1811).