Deep row incorporation of biosolids using hybrid poplar trees involves the placement of biosolids into trenches that are immediately covered with overburden, eliminating odor problems, and maintaining the biosolids in a fairly stable, anaerobic environment. The site is then planted with hybrid poplar trees, the roots of which provide a natural recycling system that utilizes the nutrients over a six-year period in most cases. This study reports the migration of nitrogen in the study area.