Manures with a particularly unpleasant odor -LRB- such as human sewage or slurry from intensive pig farming -RRB- is usually knifed -LRB- injected -RRB- directly into the soil to reduce release of the odor .

Liquid manure from pig/hog operations is usually knifed -LRB- injected -RRB- directly into the soil to reduce the unpleasant odors .
