Affects of Dairy Slurry Injection on Soil Health and Nitrogen Cycling.

Manure injection technology has been shown to provide advantages over broadcast applications. However, injection remains a small portion of total manure applications due to equipment or custom application cost. Identifying additional benefits of manure injection will make the technology more desirable. Therefore, we investigated soil health and nutrient cycling between application methods of dairy slurry. A lab study was conducted utilizing a closed volatility chamber system. Injection (INJ), surface applied (SURF), and control (CON) treatments were established in randomized complete block design. Ammonia release was quantified; soil nitrogen was analyzed at the end of the study. A portion of the soil was retained wet to perform carbon dioxide evolution and substrate induced respiration studies to estimate labile carbon and active microbial biomass, respectively. In addition, field sites were established in Spring 2016 to monitor the prior parameters with the exception of ammonia losses. Furthermore, yield and plant tissue nitrogen will be compared between treatments in the field sites. Preliminary results from the lab study indicate slurry injection reduces ammonia losses to levels similar to the control. In all cases, injected treatments retained higher soil inorganic nitrogen. If additional benefits to soil/plant nitrogen stocks or soil health are found, manure injection technologies will be a more attractive alternative to surface application.