Nutrient Characteristics of Swine Manure and Wastewater

Swine (Sus scrofa domestica) manure can be a valuable source of nutrients for crops, but overapplication can result in water and air quality issues as excess nutrients leave the plant root zone via leaching, runoff, or gaseous emissions (examples include ammonia volatilization or nitrate denitrification). Thus it is important to understand nutrient characteristics as well as the factors that influence them to optimize agricultural production systems. The American Society of Agricultural and Biological Engineers (ASABE) has published standardized values of manure properties for a variety of animals, including swine, although their latest update summarized data up through 2002. Changes in swine production and management practices since this time have resulted in a need for an updated literature review. The objectives of this chapter were to: i) summarize and compare as-excreted and as-removed swine manure characteristics in literature from North America since 2003 and ii) review current trends in swine production in North America and how these practices may impact the variability seen in manure characteristics. Besides a literature review, we also summarized nutrient data from two commercial manure analysis laboratories in the midwestern United States. Overall, manure property information was found for a variety of growth stages (phases) and manure storage types, but the most complete information was found for finishing swine manure. Data for all nutrients in swine manure were highly variable so it is difficult to make conclusions about site-specific practices. We highly recommend that producers regularly analyze their manure to more accurately understand nutrient content.