Sustainable fertilizer from reclaimed urine: A farm-scale demonstration for hay production

Project Overview

Project Type: Partnership
Funds awarded in 2013: $14,876.00
Projected End Date: 12/31/2014
Region: Northeast
State: Vermont
Project Leader:
Kim Nace
Rich Earth Institute
Abraham Noe-Hays
Rich Earth Institute

Annual Reports


  • Agronomic: general hay and forage crops, grass (misc. perennial), hay


  • Animal Production: pasture fertility, feed/forage
  • Crop Production: municipal wastes, nutrient cycling, organic fertilizers, application rate management
  • Education and Training: demonstration, extension, farmer to farmer, networking, on-farm/ranch research, participatory research, technical assistance
  • Energy: solar energy
  • Farm Business Management: whole farm planning, new enterprise development, feasibility study
  • Natural Resources/Environment: indicators
  • Pest Management: sanitation
  • Production Systems: agroecosystems, holistic management, permaculture
  • Soil Management: organic matter, soil analysis, nutrient mineralization, soil microbiology, soil chemistry, soil quality/health
  • Sustainable Communities: community planning, infrastructure analysis, local and regional food systems, new business opportunities, partnerships, public participation, public policy, urban/rural integration, sustainability measures

    Proposal abstract:

    The Rich Earth Institute (REI) works at the intersection of the sustainable agriculture movement and the sanitation industry, where there is keen and growing interest in finding ways to close the food nutrient cycle. Done well, reclaiming the nutrients in human waste provides farmers with sustainable fertilizer while reducing nutrient pollution in our waterways. Attitudes and practices toward recycling human waste are beginning to shift as both food security and the high costs of ensuring clean water and treating sewage become more pressing concerns to planners, legislators, and citizens. There is a growing body of international research on such nutrient reclamation but the U.S. lags behind. The main method currently used – field application of sewage sludge – comes with substantial disadvantages. REI is conducting the first U.S. based practical research into truly sustainable approaches.

    In 2012, REI conducted scientifically controlled field trials demonstrating the utility of recycling human urine into fertilizer for agricultural crops. A grassroots effort, the success of this project has caught the attention of national leaders in the water quality and wastewater treatment industries as well as agronomists and EPA researchers. Local farmers and the community at large have been overwhelmingly supportive of this effort, and our farmer partners are eager to increase the scale of the operation. REI’s request to USDA for a SARE partnership grant is to replicate and expand this project, bringing it to scale and investigating the logistical, infrastructural, and cost issues that determine broader feasibility.

    Outreach will be through local presentations, a field day, electronic announcements including a video, and conferences.

    Project objectives from proposal:

    For this farm scale, SARE-funded project, urine will be transported to the farm using custom septage hauling services. It will be sanitized and then stored onsite until use. Methods of sanitization will be the same as those used in 2012, but using scaled-up equipment to assess their practicality at the farm scale. One treatment consists of storing urine in a tank within an unheated greenhouse that maintains a temperature of 20 degrees C or above for a period of at least 30 days. The alternate treatment involves heating batches of urine in a solar pasteurizer to 70 degrees C for 30 minutes. Either method on its own provides suitable treatment from a health perspective, and by testing both we will provide options for others who adopt urine recycling on their farms.

    REI will construct a solar pasteurizer that is optimized for labor efficiency. The first pasteurizer performed effectively, but was awkward to operate. The 2013 system will include automated monitoring of the temperatures of the urine and working fluid, and automated control of the circulator pump. The only demand on the operator will be to check an indicator light confirming that each batch is pasteurized, and to then operate a pair of hard-plumbed electric pumps to drain and refill the pasteurizer. Operator time and electricity usage by the circulator pump and transfer pumps will be monitored as part of the cost/benefit analysis.

    Although yield results from the 2012 trial were not available at the time of this application, it was apparent from the color and the visibly stronger growth of the hay that application at the rate of 50 and 100 pounds of nitrogen/acre had a pronounced effect on the yield and quality of the hay. Urine is clearly an effective fertilizer. The 2013 season will focus on refining treatment and application processes while following up with a second season of yield measurements.

    A practical challenge faced in the first season was the provision of water at the field to dilute the urine prior to application. This was done because the urea in stored urine transforms completely into ammonia which can damage plant tissues at high concentrations. There are reports of damage to sensitive plants by urine application, but no dilution guidelines exist for hay. Dilution may also reduce ammonia volatilization losses.

    In 2012 we used a 3:1 dilution factor, resulting in a 25% urine solution. There was no damage to the plants, but hauling three times as much water as urine proved logistically cumbersome and labor-intensive. To be practical as a fertilizer, the dilution factor must be kept to a minimum—to reduce labor requirements and to avoid soil compaction over the course of multiple applicator trips.

    Our study examines the effect of both dilution rate and the timing of rainfall on yield in urine-fertilized hay. As in 2012, we will conduct our study in two areas: an area of 4m x 4m randomized blocks with four replicate blocks per treatment, and a series of more extensive 18'x300' strips, one strip per treatment. The randomized blocks will allow for statistical analysis while the extensive strips will provide a tangible demonstration.

    Three strips will receive urine at three dilution rates: undiluted, 1:1, and 1:3. Two strips will be controls: synthetic fertilizer and no fertilizer, for a total of five conditions. Since water application rates are variable, there will be no water-only control.

    Randomized blocks will receive the same treatments, plus two more: undiluted urine with 1 cm simulated rainfall either one day before or one day after fertilization. This is to see if any negative effects from applying urine in its most convenient, undiluted form, can be mitigated by a well-timed rain.

    The total NPK application rate will be determined in consultation with UVM Extension, and will be equal for each fertilized plot. The volume of urine needed will be calculated using UVM testing data for ammonia, nitrate, soluble K, and total P. A mix of urea, potassium chloride, and triple superphosphate formulated to match the urine analysis will be used on control plots. Before fertilization, samples will be taken from each plot by soil probe for measurement of gravimetric soil moisture by drying.

    Any browning of the grass after fertilization will be documented. At the second cutting, hay on the extensive strips will be baled with the number of bales being recorded. Hay from each randomized block (excluding a 0.5m buffer) will be individually cut, collected, dried, and weighed, to allow for statistical analysis of yield variation. Five samples representing the treatments and control will be taken from the bales using a hay probe, (with 20 corings representing each strip,) and seven from the randomized blocks by grab sampling, with the four replicates combined in each sample. These samples will be sent to Cumberland Valley Analytical Services for their standard forage quality analysis, to determine if there is variation in forage quality between any of the treatments.

    In our analysis, we will look for statistical differences in the yield of randomized blocks fertilized at different urine dilution rates and with simulated rain. This will let us determine the minimum dilution level needed for urine application, eliminating unnecessary and labor-intensive transport of water, which our farmer partners have identified as the most challenging aspect of urine reuse.

    We will track the total investment in equipment and labor for treatment and urine application, in order to calculate the per-unit-volume cost involved in preparing and using urine-based fertilizer. Analysis by the University of Vermont laboratory of NPK levels in the treated urine, coupled with per-unit-volume treatment and application costs, will allow calculation of the cost of using urine compared to other common fertilizers. These results will allow interested farmers to assess the viability of urine reuse on their farms.

    Results from this project will be shared locally, throughout the state of Vermont, nationally, and internationally. REI is invested in making urine reuse a viable and recognized solution, and will focus on ensuring that the project is exhaustively documented to facilitate replication, and that results are broadly disseminated through audience-appropriate formats.

    At the local level we will share information with farmers through the Brattleboro Agricultural Advisory Committee. A meeting of these farmers is scheduled in November 2012 for the specific purpose of sharing the results of REI's first season. A power point presentation, brochures and testimonial from Jay Bailey will lay a foundation for discussion about the benefits and challenges to using this new fertilizer. These farmers will be invited to follow the second season closely via email updates and site visits to Fairwinds Farm.

    Because of local interest in this project already generated through word of mouth, newspaper articles, and radio announcements, we have been approached by several land owners who are interested in using urine and having a component of future study at their farms. We will continue to publish the evolution of the work of the REI via local media and pursue collaboration with farmers reached in this way.

    Results from the project will be available to farmers throughout Vermont via the Vermont Grass Farmers Association (VGFA). In January, 2013, we will attend the annual meeting of this organization to introduce the project and present initial findings. We will maintain contact with attending farmers through email and VGFA publications.

    We will submit our final findings to sustainable agriculture publications within the United States. Results will also be shared internationally with three organizations that have been at the forefront of developing practical methods for urine reuse: Eawag Aquatic Research in Switzerland, the Stockholm Environment Institute in Sweden, and the international online Sustainable Sanitation Alliance (SUSANA).

    All project results will be posted at, which has logged visitors from 39 states and 40 countries, and 1509 visits from New Englanders, since its deployment in February.

    Presentations about all of the projects at the REI are planned in Boston to EPA personnel, to participants at the New England Water Environment Association annual conference, and in Vermont to the legislators during their winter session. The REI will be represented at the winter NOFA conference.

    We will create a 15-minute video outlining the rationale for agricultural urine reuse and documenting our project findings. We will incorporate video shot by REI staff, as well as footage recorded by professional videographers. Already, two independent filmmakers have been documenting major events this project for use in their own productions; Lisa Merton and Alan Dater of Marlboro Productions and Elise Hugus and Daniel Cojanu of Inside Out Cape Cod. They have made their footage available to us for promoting the results of this work and their contribution is at no cost to the REI.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.