Introduction
The Livestock manure contains significant quantities
of salt, nitrogen (N), phosphorus (P), and potassium (K), as well as lesser
amounts of nutrients such as calcium, magnesium, manganese, zinc, copper,
and sulfur. When manure is properly utilized, it can greatly increase soil
fertility, improve soil properties, and reduce commercial fertilizer costs.
However, improper handling, storage and application of manure presents
multiple opportunities for both ground and surface water contamination.
Water moving across the land surface or through the soil profile can transport
salts, pathogenic organisms, nitrates, and organic solids, all of which
can degrade water quality, both on the surface and underground. Livestock
manure, manure stockpiles, and storage lagoons all represent potential
sources of pollution.
Guidance Principle
Collect, store and apply animal manures to land at agronomic
rates to ensure maximum crop growth and economic return while reducing
the potential for point or nonpoint source pollution in order to protect
water quality.
Stored animal waste
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BMPs for Manure Utilization
3.1 Manure should be tested
for salt and nutrient content by a reliable laboratory to determine soil/crop
compatibility prior to field application.
3.2 Livestock producers
should ensure that the land available for manure application is sufficient
for the amount of manure generated by the animal feeding operation (see
box on page 16).
3.3 When calculating long
term manure loading rates, a reasonable estimate is that 50 percent of
total nitrogen from applied manure is available in the first cropping season;
25 percent in the second; and 12.5 percent in the third. Use soil test
and manure test data to help determine available nutrients.
3.4 Manure application
rates should be based upon a site specific nutrient management plan that
includes:
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Consideration of all plant-available nutrients from manure,
irrigation water, crop residues, residual soil nutrients, and soil organic
matter. These factors should be based upon laboratory analyses of soil,
water, and manure.
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The appropriate manure loading rates are determined using
plant-available nutrients in the manure and crop yield goals. Additional
commercial fertilizer should only be applied when soil-available nitrogen
and phosphorous, plus nutrients from manure application, do not satisfy
crop needs.
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Application rates are best determined by actual soil samples
and manure nutrient analysis.
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