A sound manure nutrient management plan requires knowing what is in the manure, availability of nutrients in the soil, manure nutrients and fertilizer to be applied to meet crop nutrient demand, strategy for application, and record keepping and monitoring. A sound long term approach to efficient and environmentally friendly use of manure nutrients is to apply at rates which balance with crop demand and use over time. In the short term, rates of manure appropriate for next year’s crop may be calculated based on the anlysis of the manure content and predicted availability of the manure nutrients to be applied along with a soil test and required rates for individual nutrients as used for application of commercial fertilizer.

With a source of fertilizer such as liquid swine manure in which much of the nitrogen is contained in immediately availbable plant form ammonium, similar to commercial fertilizer the application in late fall or spring is desirable in order to reduce the opportunity for conversion of ammonium to the nitrate form which is more suseptible to leaching and dentrification. To reduce the potential for losses, these manures should be applied as close to the timeof plant nutrient demand as possible. Some challenges are faced in dealing with manure as a fertilizrer and soil amendment, including the inherent variability in manure, its low nutrient content and constrictions in transportation and application technology.