Match phosphorus application rates to crop yield goals and soil test levels to avoid excessively high phosphorus levels in the soil. Use regular soil testing to track phosphorus levels over time. If manure is applied, take appropriate credit for phosphorus in the manure so unnecessary amounts of commercial fertilizer are not added. Modernization of the livestock industry has given rise to highly efficient production systems under one roof in place of the traditional pastured herd. These operations have also created new management challenges in the collection, storage and handling of large quantities of manure.
Manure contains nitrogen, phosphorus, inorganic salts, organic solids and microorganisms.
All of these are potential contaminants of both surface and ground water. The runoff from poorly designed feedlots and manure storage facilities can be a direct source of surface water contaminants. Livestock allowed to stand in streams or ponds deposit manure directly into surface waters. Excessive or improperly timed manure applications on permeable soils can result in elevated nitrate levels in shallow ground water. Manure applications are also a source of phosphorus in runoff to surface waters.