Understanding appropriate fertilization requires a look at the soil-plant-animal continuum and specifically the cycle that nitrogen follows since nitrogen is the nutrient most frequently needing to be replenished.

Seeing how nitrogen travels in the environment and tracing a unit of N through its natural pasture cycle will pinpoint many important aspects about fertilization. Look at a unit of N as organic N in the humus (soil). It is mineralized by soil microorganisms to nitrate. As nitrate, it is taken up and used by grass or clover plants. Since clover is a nitrogen-fixer and supplies most of it's own N from the atmosphere, our N unit can be added to the soil N pool or even supply some N to the grass via underground transference. As livestock consumes the grass or clover plants, some of the N unit is kept in the animal as protein and may eventually find its way into meat and milk. Most of what is not used in energy production is returned to the soil via animal wastes, so our N unit returns to the soil and completing the cycle. This is an important way of replenishing the soil and maintaining a natural nutrient recycling.

However, livestock do not deposit their waste material evenly and in proper concentrations. Manure can be collected, mixed with water to make a manure slurry and distributed onto field and pastures. A slurry will provide nutrients and water, lessen wind and water erosion, improve soil aeration, and promote the growth of beneficial microorganisms. However, when more nutrients are put into the ecosystem than are being utilized, excess may lead to problems such as lower water quality, crop burning, accumulated salts which impair soil structure and decrease water movement rates, inhibiting plant growth and soil sealing.

Manure can be analyzed at a lab to determine the nitrogen, potassium, and phosphorus content. Collect samples at different locations to get a representative collection. Mix the samples together and put the sample in a plastic jug or jar with a screw lid. Keep the sample in a cold location to prevent gas build-up and rupture of the the container. Send the sample to a lab.

Once the manure has been analyzed, proper application of the manure requires an understanding of nutrient losses that occur during collection, storage, and distribution. Up to 80 - 90 percent of the initial concentration can be lost. The frequency and method of collection, the type of animal housing, and handling system affect the final nutrient composition. The duration, type and location of storage have direct influences as well. Covered storage units generally are cooler and have less biological activity than open units. Open storage units are open to precipitation, and thus susceptible to leaching and runoff.

Manure must play a part in replenishing the soil - but few rely solely on it. Forage-livestock producers must look carefully at what nutrients are needed in plant growth and apply them in a wise and economical manner.