Sheet Mulch Using Cardboard and NFTs

Progress report for FW19-348

Project Type: Farmer/Rancher
Funds awarded in 2019: $11,000.00
Projected End Date: 07/31/2022
Host Institution Award ID: G357-20-W7501
Grant Recipient: Takai Farm
Region: Western
State: Guam
Principal Investigator:
Glenn Takai
Takai Farm
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Project Information


Sheet Mulch Using Cardboard & Nitrogen Fixing Trees (NFTs)

In all the crops I grow the most problematic issue I face is weed management.  I have tried various methods of controlling weeds on different crops whether short or long term.  In Guam, weeds grow at a very fast pace.  Currently, I pull weeds along with hired help for fast growing crops such as cucumbers and long beans.  In longer term crops such as papaya, hot peppers and calamansi, I use herbicide and bush cutting (commercial high powered gas trimmers) to suppress weeds.  Bush cutting is a highly used method of grass cutting in Guam due to rocky uneven surfaces.  These bush cutters do extensive damage to crops and can be very costly.   A secondary problem is that my farm is cultivated year after year often without periods of fallow.  The soil has no time to recover and methods of building up soil are low to none.

I intend to approach this problem using sheet mulch as a solution.  Profit margins are impacted because the cost to control weeds coupled with reduced production.  Cardboard is an abundant resource in our remote island due to high imports creating much waste into the landfill.  I would like to research the effects of using cardboard and NFTs as sheet mulch to manage weeds as well as improve soil quality through adding organic matter.  The NFTs will be established along the perimeter of the farm to be used as a windbreak.  Commercial farmers on island often use plastic mulch and spray herbicide as a means to control weeds.  This solution provides organic matter into soils while recycling landfilled cardboard.  I will conduct a workshop as well as on site demonstrations for other farmers to observe.  The data I would collect will include labor hours saved through mulching, production, and compared pre and post soil samples.  

Project Objectives:


  1. Research the cost analysis and production of farmed crops with and without sheet mulch
    • data collection continues in gathering and prepping field for sheet mulching.
    • comparative results will presented upon completion of project
  2. Research the quality of soil before and after farming crops via soil samples
    • baseline soil sample has been completed
  3. Establish perimeter windbreak of Nitrogen Fixing Trees (NFTs)
    • Collected propagation material from UOG/AES research station
    • Plants have been propagated and maintained and are ready for planting.  Due to the pandemic, acquiring plant material, propagation timing, as well transplant date has been delayed.  Updated plant schedule will be in the next upcoming rainy season (beginning in May-June).
  4.  Create a storage facility for cardboard boxes on site
    • Storage facility will be purchased once it is locally available and in stock
  5.   Design a field layout having row plots of beds with and without sheet mulch
    • Farm field cleared and prepped for farm plots
    • Completed in partnership with technical advisor
  6. Mulch planted rows with proper amounts of cardboard and NFTs in accordance with proper carbon:nitrogen ratios
    • Established network of schools and local convenient stores for the mulching material within the vicinity of farm site
  7. Conduct a workshop showing the costs and considerations of sheet mulching, soil and plant health, and production


Months 1-3:  Research cost analysis and production of crops without sheet mulch.  Research soil quality and obtain initial soil sample

Establishment of NFTs.  This will involve seed collection and nursery establishment.  Seeds will be planted into trays and nursed until they are ready for transplanting.  During the time of seedling growth, site preparation will be done for perimeter windbreak planting.

Months 4-12:  Seedlings for windbreak will be transplanted and farm plots will be established.  Cardboard storage facility will be created

Months 13-15:  Crop rows will be mulched in accordance to design.  

Months 16-24:  Data collection & analysis.   Field day for other farmers to be held.


Click linked name(s) to expand
  • Mark Acosta - Technical Advisor


Materials and methods:

Materials & Methods

The design will begin with planting a double windbreak along the perimeter of the farm.  This windbreak will consist of NFTs.  This will provide the green manure to be paired with cardboard obtained from bins of schools and department and retail stores.  A recommended carbon to nitrogen ratio will be used by the local cooperative extension.  A storage facility will be established on farm site to protect the integrity of the cardboard boxes from inclement whether.  Once the NFTS have grown out, a single portion of the double windbreak will be harvested to mulch crop beds.  Prior to planting crops in crop beds, soil will be collected and taken to the local extension office for soil testing.  Next, field crops will be planted along with drip irrigation lines above crop beds.  Cardboard will then be laid and NFTs above so it will hold the cardboard from flying.  An equal number of rows will be planted with the sheet mulch as with non mulched rows.  Plants will be allowed to grow out to harvest and data will be collected.  The data to be collected will be: days to harvest, # of marketable fruit, & total yield.  Also, upon completion of the project, a post soil test will be taken to compare nutrient content in soil and organic matter %.  I will determine if the project is successful if the results of the data a favorable to mulched crop beds.

Year 1 update:  (Timeline was reset due to Farm Equipment (tractor) broke down.  The fuel pump broke and the manufacturer (Kubota) no longer made the replacement part.  Search and modification was required in order for the tractor to be operable.  This took a few months due to shipment into the island as well as part modification from a local hydraulic hose fabrication and repair shop.  The extension request was successful and greatly appreciated.  This is why the timeline was adjusted.  Since that time what has occurred is a as follows:

  1. Data collection continues in gathering and prepping field for sheet mulching.  Comparative results will be presented upon completion of project.
  2. Baseline soil samples have been completed via University of Guam Soils Lab.  
  3.  Windbreak seeds (Sesbania grandiflora) have been collected and planted from my technical advisor at the university.  Due to the pandemic, acquiring seeds and propagation timing, as well as transplant date has been delayed.
    Seeds were planted into D6 tray tubes and placed in a misting system until germination.  They have been growing in tubes for a few months, however, they have not been transplanted into the field due to dry season.  The are well established and can be planted into the ground upon the start of rainy season.
  4. A storage facility will be purchased once it is locally available and in stock.
  5. Windbreak planting perimeter field has been cleared, prepped, and maintained ready for NFTs to be planted.
  6. Farm field has been cleared and field has been prepped for farm plots for all crops.  Design was completed in partnership with my technical advisor.
  7. Established  a network of schools and local convenient stores for mulching material within the vicinity of the farm site.
Participation Summary

Educational & Outreach Activities

5 Consultations

Participation Summary:

Education/outreach description:

Educational Outreach Plan 

  1.  Workshops, conferences, and other community meetings.  (After year 2 when results are obtained)
  2. Extensions fact sheets on the use of sheet mulching with cardboard and NFTs on all field crops  (After year 2 when results are obtained)
  3. Field day at the farm site (During 2nd year after NFTs are established and are usable)
  4. Extension faculty and field agents will conduct presentations on the benefits of sheet mulching using cardboard and NFTs.  (After year 2 when results are obtained)
  5. Extension publications will be developed and disseminated both through local extension offices and through the internet as online PDF publications.  (After year 2 when results are obtained)

Edit 3/14/21 - As indicated in numbers 1,2,4, &5, these outreach activities as well as fact sheets will be conducted and produced respectively after year 2 when results are obtained

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.