Goldberg, J. 2026. Ammonia volatilization from urine-derived fertilizers. Thesis, University of Michigan, Ann Arbor, MI.

Urine derived fertilizer (UDF) is a promising alternative to conventional Haber-Bosch derived fertilizer due to its favorable production requirements and renewable source. Nitrogen (N) from Haber-Bosch derived inorganic fertilizers is primarily lost through runoff and leaching, which cause numerous negative impacts on surrounding ecosystems. UDFs differ in chemical makeup and concentration from Haber-Bosch fertilizers. These compositional differences and their resulting interactions are important to understand in order to effectively incorporate UDF into agroecosystems and improve N use efficiency. Specifically, the performance of UDF across varying agroecosystems remains understudied, and it is uncertain how UDF may differ in N uptake and loss pathways relative to commonly-used fertilizers. To address these knowledge gaps, this experiment aimed to determine: 1) if the greater ammonia content in UDF relative to UAN 28% (Urea-Ammonium Nitrate solution, Fi) would lead to greater ammonia volatilization; 2) whether more sustainable agroecosystem management can reduce ammonia volatilization from UDF; and, 3) whether the co-application of compost reduces ammonia volatilization from UDF. We established a field experiment to measure ammonia volatilization from UDF and Fi within the ongoing Kellogg Biological Station Long-Term Agroecosystem Research Aspirational Cropping Systems Experiment, which compares the impacts of sustainable (“Aspirational”, ASP) and conventional (“Business-As-Usual”, BAU) agricultural practices. Acid traps were deployed to capture volatile ammonia for 9 days following 3 fertilization events. There was significantly greater ammonia volatilization from the UDF than the Fi in both the ASP (p = 0.000731) and the BAU (p = 5.28e-05) cropping systems. There was also significantly greater ammonia volatilization in the BAU system than the ASP system (p = 0.0256) in the first 3 days, but the loss of the data from 2 traps kept the 9 day observations from reaching significance in this model system. The co-application of compost did not have a significant effect on ammonia volatilization. Our findings suggest that the reduced volatilization in the ASP system is due to the reduced fertilizer input rather than demonstrably different rates of N assimilation or retention from UDF. Alternate application methods and timing for both the UDF and compost that reduce the UDF’s direct exposure to the atmosphere could mitigate ammonia volatilization and improve N assimilation and retention in the soil.

Associated Treatment Areas:

• ASP3 Aspirational
• BAU2 Business as Usual
• LTAR Research Context Info related to LTAR

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