Farm-Scale Application of Concentrated Urine-Derived Fertilizer: Evaluation of a Roller Pump for Precise and Consistent Side Dressing of Sweet Corn

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Commodities

• Vegetables: sweet corn

Practices

• Crop Production: application rate management, nutrient cycling
• Sustainable Communities: local and regional food systems

This project builds upon two previous SARE Partnership projects with John Janiszyn, who operates Pete's Stand in Walpole, NH, with field sites in Vermont.  In these previous projects, we designed a gravity-fed method for applying sanitized urine fertilizer to his sweet corn, followed by successful experiments using a urine concentrate to increase application efficiency. This project will give further attention to the method of dosing the urine onto the field, addressing needs for both consistent dosing rates and minimal ammonia volatilization. We will design a ground-driven peristaltic (or "roller”) pump system to dispense urine concentrate into crop rows, and we will evaluate its efficacy through quantitative testing, farmer feedback, and leaf tissue analysis of fertilized crops. The roller pump system design will be documented in a short video and made accessible to farmers interested in adopting urine-fertilization technology. 

This project will evaluate the ease of use, effectiveness, and consistency of a customized fertilizer applicator using a ground-driven "roller pump" for applying a sanitized, concentrated urine-derived fertilizer to sweet corn. We will purchase a multi-tube roller pump and the necessary auxiliary component parts to assemble a complete system that can 1) consistently deliver the desired amount of urine fertilizer per acre (adjustable by the farmer), 2) cover the urine fertilizer with soil immediately upon application to prevent ammonia loss, and 3) be easy to operate and maintain. Furthermore, we will test the practical limits of the system’s dosing rates and discover any mechanical weaknesses. We will monitor urine-fertilized crops for signs of healthy development (visually and through tissue analysis), and note any differences in health from synthetically-fertilized crops. From this assessment, we hope to determine the potential for this applicator to be used for other crops and application contexts. Desired outcomes of the roller pump system testing include:

Deliver a consistent and correct urine fertilizer volume per acre 

1. There is no variation in the quantity of fertilizer dispensed over a set distance when the tractor is driving at different speeds
2. The drive wheel consistently powers the pump as the tractor moves over the ground, even when encountering bumps, divots, etc.
3. The pump provides a practical flow rate for urine concentrate and delivers urine at the correct depth and location relative to row crops
4. There are no differences in plant development and overall health during the growing season between plants receiving urine fertilizer or synthetic fertilizer 

Ammonia volatilization is limited during application

1. The urine fertilizer is immediately buried in soil upon application to the ground
2. Little to no ammonia odor is present following application

The roller pump system is easy to operate and maintain and contexts for its potential use are understood

1. The farmer-partner reports an easy-to-operate user experience with minimal challenges
2. There are no mechanical failures or signs of wear/weakness in any system components
3. The system is expected to be useful for other crops and application contexts besides sweet corn
4. The system limits are understood through a determination of the maximum and minimum practical dosing rates possible