It is well-known that the application of hog manure to land is an economical and environmentally sustainable method for the utilization of the nutrients and other components in the manure. Manure application can increase soil quality and productivity, at least in the short term, on most soils. However, soil quality and productivity can severely reduced in the long-term unless precautions are taken with respect to the loadings and frequency of application of manures. Sustaining the hog industry, through good manure management, is one method to ensure the continued growth of the hog industry in the province. Excessive accumulations of phosphorus, metals such as copper and zinc, sodium and other soluble salts can reduce soil quality and productivity. The loading rates and period of time a soil or parcel of land can be used for manure application depends on soil properties and the concentration of various constituents in the manure. Manures vary in the concentrations of metals (such as opper and zinc), depending on the type of hog operation (feeder, sow, nursery or farrow to finish barns) because of the varying concentrations of these minerals used in the feed. Soils with pH values of less than 6.5 are sensitive to metal loadings of copper and zinc, and crop yield and quality may be reduced if metal applications are high. sodium and other soluble salts found in the manures, also depend on the mineral supplements in the feed, as well as the source of water used to operate the hog facility. any soils in Manitoba are highly sensitive to sodium and salt applications. Another concern is the ratio of nitrogen to phosphorus in the manures. If the nitrogen to phosphorus ratio in the manure is much less than the ratio of nitrogen to phosphorus removed by crops, and the application rate of the manures was based only on available itrogen, phosphorus will accumulate in the soil. The build-up of phosphorus in the long-term can result in phosphorus runoff to surface waters (a decrease in water quality) and may cause yield reductions.
This investigation was an exploratory study to determine whether or not decreases in soil quality
and productivity were likely to occur due to the long-term applications of manure to Manitoba
soils. Several types of hog manures produced by various hog operations in Manitoba were
examined, and the effects of these manures on soil quality and productivity were assessed.