Project Clearinghouse

FarmFuture

Sustainability Problem and Proposed Solution: 

Crop production currently relies on fertilizer; tillage; single use plastics; and long hours bending down to harvest, weed fields, and repair irrigation equipment. In recirculating aquaculture production, waste water rich in plant available nutrients is routinely expelled to flush solid waste from filters. Instead of disposing of this water, we are testing its efficacy as fertilizer in grow systems designed to maximize nutrient and water use efficiency and minimize labor.

Jump to: Contact | Project Description | Metrics for Success | Results
Project Categories: 
Land, Habitat, Watershed
Food
Awareness, Education & Engagement
Social Justice
Waste & Recycling
Water
Project Status: 
In Progress
Campus Organization: 
Carbon Fund
Center for Agroecology & Sustainable Food Systems
Affiliated Department, Unit or College: 
ENVS
Project Location: 
On campus

Center for Agroecology

Some happy baby red lettuces enjoy their water saving planters and fish effluent based fertigant!


Stakeholder Contacts: 
Contact NameEmail AddressContact NumberDepartment
Connor D Greenwood
cdgreenw@ucsc.edu
6267337778
ENVS

Project Description: 

FarmFuture is testing and demonstrating the potential synergies between agriculture and aquaculture. Using our newly designed SIPRs or Sub-irrigated Plant Recyclers, we plan to up-cycle the nutrients being expelled from our aquaculture system and utilize other forms of nutrient cycling such as in-bed composting, vermicomosting (composting with worms), and nitrogen fixing by cover crops to grow crops without the addition of fertilizer.

Our first trial tested the partial replacement of fertilizer with effluent and found that we could in fact grow crops, in this case lettuce, using an effluent based fertigant solution. Unfortunately we did not see a very large difference in plant growth across the three treatments, effluent based fertigant, non-effluent based fertigant, and unamended well water. This was likely due to the lettuce's shallow rooting zone, which limited their ability to uptake nutrients from the reservoir about a foot below them. This will be addressed this coming spring when we plant them with a brassica, likely kale, for our next growth trial.

Metrics for Success: 

I will consider the project a success if the SIPR beds produce marketable strawberries with minimal labor using our effluent. If we find that berry yields are similar between aquaculture waste water fed and fertilizer fed SIPR beds, it will suggest that in this application, effluent is as effective as fertilizer at increasing berry yield. If tap water fed beds perform as well as the waste water and fertilizer fed beds, it suggests that the vast majority of the bed's fertility is a result of the decomposing compost layer, submerged mulch layer, and cover crop planted prior to the cash crop. I will also consider the project a success if it inspires others to dive deeper into the benefits integrated agriculture aquaculture or sub-irrigation.

Next Steps: 
Purchasing all materials, constructing and cover cropping the beds, terminating cover crops and planting strawberries, collecting and analyzing data on yield and soil properties, assessing results and seeking grant opportunities to continue exploration into IAA and decoupled, soil based aquaponics,
Result Categories: 
Education/Outreach
Data Collection & Analysis
Results: 

Our SIPR beds will also allow us a water, nutrient, and labor efficient way of upcycling our waste water to produce crops. This will lower our own environmental impact over time, but will also demonstrate the benefits of integrating agriculture with aquaculture to both farm visitors, and industry stakeholders alike. Our project will also deliver preliminary data and results that will likely be used to help secure a larger grant to continue this work. The project is currently in its preliminary stages; however, it is my hope that the beds will stay in production for years to come with the support of members of the Kapuscinski/Sarker lab team. Anyone curious about the state of the beds is encouraged to visit the farm and see them for themselves, or reach out to me for an update. I will also track updates on the uscs_aquaculture instagram page.