Using washed-up semi-decomposed seagrass in sweet potato cultivation

Project Overview

Project Type: Research to Grass Roots
Funds awarded in 2020: $64,747.00
Projected End Date: 08/31/2023
Grant Recipient: College of Micronesia
Region: Western
State: Federated States of Micronesia
Principal Investigator:
Steven Young-Uhk
College of Micronesia

Project not moving forward due to PI role change as of November 2020.


No commodities identified


No practices identified

Proposal abstract:

Seagrass that has washed up on shore is abundant and has been used for centuries on Yap Islands in traditional agriculture. Traditionally, semi-decomposed seagrass is incorporated to create raised beds where crops are grown for several years or until a new crop takes its place. Sweet potato is a desirable food crop and is well suited to poor soil conditions, however the highly weathered, acidic, poor nutrient soils of Yap require amendments of organic material such as crop debris, compost or manure to be productive. While compost and manure are effective, they are costly, labor intensive, and in short supply. Washed-up seagrass is free, abundant, easily transported, and can be an inexpensive source for soil organic matter and nutrients. This project includes two studies that will be replicated at 20 on-farm sites to demonstrate yield and economic feasibility of growing sweet potato with semi-decomposed seagrass applied at 2 rates (medium and high) in raised beds (study 1) and in containers (10 gal. grow bags) (study 2), and both will be compared with commercial fertilizer (control). The outreach component of the project will be the on-farm trial demonstrations where other farmers, agriculture professionals, and interested individuals will be invited to visit and observe the studies. A workshop will be conducted to share and discuss the results with other farmers and agriculture professionals. A brochure will be developed and printed for distribution to the public. A short video recording will also be produced to highlight the successful production techniques. The video will be uploaded on YouTube with the link shared through our network contacts. We will publish a report to highlight our successes and challenges so that other island communities can gain from our experience.

Project objectives from proposal:

The overall objective of this project is to demonstrate the benefits achieved through applying semi-decomposed seagrass to sweet potato production. Farmers benefit by increasing their knowledge and ability to utilize a local resource (semi-decomposed seagrass) to produce a high-value crop (sweet potato), and they will gain economically when they sell their excess crop at the local market. Household food producers will benefit when they produce more food to feed their families, and affordable quality food is always in short supply in Yap. Society as a whole will benefit when trash is removed and properly disposed when seagrass is collected. Specific objectives are:

  1. Increase use of washed-up semi-decomposed seagrass as a soil amendment
  2. Increase yield and extend production cycle of sweet potato by applying semi-decomposed seagrass in raised beds
  3. Increase adoption of containers (10 gal grow bags) for sweet potato production in urban areas where agricultural land is scarce or not available
  4. Improve the economic return for sweet potato by substituting semi-decomposed seagrass for other more costly soil amendments (e.g., compost, manure, commercial fertilizer)
  5. Provide agricultural educators with on-farm demonstration sites for teaching venues targeted to farmers and household food producers
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.