The 3F’s of Manure Management

Chicken cartoonFor many centuries, animals and crops were produced and consumed within the same farm unit. Livestock manure, used as fertilizer and fuel, contributed to the self-sufficiency of most farms. However, in the 20th century, many farms began focusing on either livestock or crops as opposed to both. Also during this time, advances in manure-handling, treatment and disposal techniques were developed with the intention of storing and diluting the highly-concentrated nutrients before releasing it into the environment. Many current manure management techniques such as lagoon storage are only temporary relief for a long range problem. Livestock manure remains a major cause of water pollution and the difficulties of animal manure management represent significant challenges to farmers, planners, scientists and regulatory agencies of the 21st century. However, animal manure has high energy yield and profit potential if used as fertilizer, fuel, and feed. A combination of two or more of these topics may economize farm management and contribute to environmental quality. These topics are:

Fertilizer. Animal manures are valuable sources of both macro and micronutrients essential for crop growth. Generally, about 75% of nitrogen, 80% of phosphorous, and 90% of the potassium ingested by livestock are excreted in manure. On the basis of readily available nutrients, one ton of average manure yields five pounds of nitrogen (N), one pound of phosphorous (P2O5), and five pounds of potassium (K2O). The N/P/K deficiency of manure recognized for much crop production can be balanced by adding chemical fertilizer.

Fuel. Animal manures, crop residues, and a mixture of both are potential sources of biomass for generating biogas energy. The biogas can contains 60 to 70 percent methane with a heat value of 500 to 700 BTU/cubic foot.  There is also significant potential for generating on-farm electricity from this biomass.

Feed. Processed manure has a high nutrient value and can be added to livestock ration. Nutrition value of the processed manure is influenced by ration fed to livestock as well as by manure storage and treatment. Using animal manure as a nutrient source for an aquaculture system is another attractive on-farm option.  The products from the aquaculture system can be fed to fish, poultry, or other livestock, and byproducts used as a fertilizer or digested to produce biogas.

Utilizing the 3Fs (fertilizer, fuels, and feeds), especially in conjunction with one another, may offer an attractive alternative to current practices and a logical step toward improved rural environments. When all three methods are used, it is possible to store the abundant amount of carbon in manure which leads to improved soil structure and function. The advantages and potential profits from integrated manure management using the 3Fs will become evident when explored within context of Rural System concepts.

This post is guest-authored by Dr. Tamim Younos, Water Resource Specialist and President of the Cabell Brand Center and edited by Risa Pesapane. 

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About Risa Pesapane

Risa is the Project Director for Rural System, Inc. and is an experienced research biologist and wildlife ecologist.

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