Frank said NU is studying both the effects Nebraska's unique environmental conditions have on biosolids and ways producers can apply them effectively. Organic nitrogen in biosolids is not immediately available to the plant. It has to undergo a transformation called mineralization after application. To determine mineralization rates, biosolids are applied to field plots in different quantities. Mineralization tubes measure the amount of nitrogen transformed.
Experiments also compare biosolids' effectiveness as a commercial fertilizer replacement.
A large volume of biosolids must be applied the first year to meet crops' nitrogen needs, Binder said, and heavy application makes the potential for nitrate leaching into groundwater a major concern. Unused nitrogen mineralizes over several years, producing nitrates that can contaminate groundwater if they leach below the plant root zone. The NU study's goals include developing recommendations for optimal application to reduce leaching. IANR researchers recently finished half of a four-year study. The project also examines how application time and method affect fertilizing value.