WASTE MANAGEMENT
PIH-25
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA
Fertilizer Value of Swine Manure
Authors
Alan L. Sutton, Purdue University
Stewart W. Melvin, Iowa State University
Dale H. Vanderholm, University of Illinois
Reviewers
E. T. Kornegay, Virginia Polytechnic Institute
J. Ronald Miner, Oregon State University
Swine manure contains fertilizer nutrients that can support crop production and enhance the soil’s chemical and physical properties. Thus, manure can be an asset to a swine operation if its nutrient value is maximized. The purpose of this fact sheet is to provide the swine producer with pertinent information on which to base decisions concerning the handling and use of swine manure as a fertilizer source. Discussed here are: (1) the nutrient content of manure, (2) how to determine application rates, (3) the need for supplementary fertilizer and (4) related manure handling management suggestions.

Factors Affecting Fertilizer Value of Manure
Several factors determine the type and amount of nutrients in swine manure and their eventual availability to plants. These factors are: type of ration fed; amount of feed, bedding and/or water added; method of collection and storage; time and method of land application; nitrification and soil characteristics.

Type of Ration Fed
Increasing levels of additives (copper, arsenic, etc.) and inorganic salts (sodium, calcium, potassium, magnesium, phosphate, chloride, etc.) in swine rations will change concentrations of these elements in manure. Certain additives, such as copper sulfate and arsenic compounds, may also change the decomposition rate of manure solids. There is concern about the potential toxic effects of increased levels of heavy metals and salts in soil and plants as a result of high application rates of manure. Routine soil tests and analysis of manure are recommended to monitor the nutrient levels in the soil, especially on land receiving heavy manure applications.

Amount of Feed, Bedding and/or Water
Bedding and water that get into manure dilute its nutrient concentration, thus lessening its value as fertilizer
applied to the land. Feed spillage, on the other hand, will increase manure nutrient concentration for land application. (Feed spillage and inadequate agitation may cause sludge buildup and create problems for liquid manure removal.)

Method of Collection and Storage
The type of housing and/or manure handling method greatly affects the nitrogen concentration of swine manure (Table 1). Major N loss occurs when manure is dried by sun and air movement or is leached by rain in the open lot system. In contrast, comparatively little nitrogen is lost from manure in a completely covered feedlot when a manure pack or anaerobic storage systems are used. Loss of nitrogen from manure is greatest in long-term partial treatment systems, such as lagoons.
Table 1. Approximate nitrogen losses from swine manure as affected by handling and storing.	
Handling and storing methods	Nitrogen loss*
	%
Solid systems	
  Manure pack	20-40
  Open lot	40-60
Liquid systems	
  Anaerobic storage**	15-30
  Lagoon***	70-80
*Based on composition of manure applied to the land vs. composition of freshly excreted manure.
**Concentrated manure with little water added.
***Manure plus dilution water added for biological treatment and odor control.