Human urine is receiving new attention from farmers, researchers, policy makers, and the wastewater treatment industry. Long seen as a waste to simply be disposed of, two factors are forcing a reevaluation of its management: 1) increasing damage to water quality caused by nutrient pollution stemming from human urine in wastewater, and 2) the vast potential for fertilizer production using the nutrients in human urine.
The Rich Earth Institute has been at the forefront of urine-derived fertilizer (UDF) research since 2012, with undertakings that include developing the nation’s first community-scale urine fertilizer production program, and conducting SARE-supported research establishing urine as a viable and sustainable replacement for synthetic fertilizer in hay production.
Animal feed and forage crops are an ideal initial use for UDF, because they avoid the potential squeamishness people could feel about using UDF for food crops. This project has two goals that will facilitate adoption of UDF for feed crops: 1) quantify and manage nitrogen loss through ammonia volatilization, which is one of the most challenging aspects of using urine-derived fertilizer in hay production, and 2) determine, through collaborative farmer/researcher dialog, how current fertility management strategies and existing equipment can be adapted to incorporate UDF.
Project objectives from proposal:
Field Trials: We will determine relative rates of ammonia loss when urine-derived fertilizers (UDFs) are applied to perennial grass using different fertilizer preparation and application methods and under varying soil moisture and wind speed regimes. We will establish a range of conditions where UDFs can be applied with acceptable ammonia volatilization rates to enhance nitrogen retention in soils. By identifying surface application methods and conditions that minimize ammonia volatilization, we will increase the efficacy and economic benefit to grass farmers using UDFs.
On-site visits: In dialog with farmers from a diverse array of livestock farms, we will explore the best strategies and opportunities for using current or slightly modified equipment to use UDFs effectively on their farms for hay, corn, and other feed production while minimizing ammonia loss through tillage or judicious surface application. The documentation and dialogue will address fertility management practices (including use of liquid manures and digestates); equipment used; timing and weather conditions of application; and different soil management practices. The goal is to strategize with farmers the practices, tools, techniques, and critical research to make most effective use of UDFs under varying management conditions.