Hog manure is recognized as a valuable resource, largely because the N it contains is mostly in the form of NH4-N. This binds to soil and is less prone to leaching to groundwater than NO3-N. Nevertheless, monitoring nutrient loading to land reliably is more difficult with manure than with inorganic fertilizer. Manure is variable in composition from one store to another, and difficult to maintain in a homogeneous state due to settling of particulate material. Few data exist on the variability in composition of hog manure during application to land. For a study of the feasibility of analyzing hog manure rapidly with near-infrared spectroscopy, 121 manure samples were collected from 13 hog operations in the vicinity of Winnipeg MB between 28 September and 4 November 2000. All but two of these operations held the manure in
earthen stores, one had a slurry store and a secondary lagoon, and one had above ground storage. Six of the operations were visited once and seven were visited from two to seven times during pump-out from agitated lagoons. Several of these were visited at the start and finish of pump-out, as well as periodically in between. At most sites, a pail was filled from the drop-out valve on the umbilicus during actual field application. The manure in the pail was well-stirred and four 1-L subsamples were taken immediately after one another in polyethylene bottles. Samples were analyzed by the Freshwater Institute Analytical Laboratory for pH, conductivity, density, ammonium-nitrogen (NH4-N), total dissolved nitrogen (TDN), particulate nitrogen, dissolved phosphorus (dissolved P), particulate P, and particulate carbon (particulate C, i.e., a
measure of the particular organic matter). Eighty of the 121 samples of manure were analyzed for 31 metals and minor elements by inductively coupled plasma spectrometry, and for % moisture by Norwest Labs. Some or all of the values for Ag, As, Bi, Pb, Sb, Se, Sn, Ti and V were below the limits of detection for the method. These are not considered further here.