Building Soil and Plant Health with Compost and Compost Teas in Coffee Plantations

Final report for FS20-324

Project Type: Farmer/Rancher
Funds awarded in 2020: $12,443.00
Projected End Date: 09/30/2023
Grant Recipient: Finca La Jiba
Region: Southern
State: Puerto Rico
Principal Investigator:
Gabriela Medina
Finca La Jiba
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Project Information


As climate change begins to be a serious challenge to farmers it is precarious to have natural resources regenerate. By applying compost and compost teas large populations of beneficial bacterias, nematodes, fungi, and protozoa can correct deficiencies in soil food web regenerating soil health by increasing moisture and fertility and acting as organic/natural pesticides bettering plant health.

Project Objectives:

In a term of a year, we will do three applications of fifty yards of compost in a fifty by fifty experimental space producing three cycles of peppers. Every week we will apply twenty-five gallons of compost tea at a rate of five gallons daily for five consecutively days giving it a rest of two days between weekly applications. Before and after each producing cycle we will take a soil sample to measure soil fertility and biota. Insect scouting will be held monthly and pepper yields will be measured at the end of each producing cycle.  A control area of fifty by fifty will also be produced with the same variety of peppers to measure differences in yields, pest incidence, soil fertility, and biota. 

Compost and compost teas apply will be made and manage at the farm to ensure the best quality. For these, we will plant legume cover crops of Canavalia ensiformis which will be harvest every sixty days for composting with wood chips of Leucaena leucocephala an abundant bush on the island. At the end of the investigation control data will be compared with experimental results.  


Click linked name(s) to expand/collapse or show everyone's info
  • Maria Rosario (Educator)
  • Eric Schoenbohm - Producer


Materials and methods:

The experimental trials on this project were conducted with the means of bettering the soil condition with compost and compost tea applications. For each Robusta variety coffee tree an amount of 2 pounds of compost were applied in a term of 4 months. As a compost companion a solution of effective microorganism (EM) was spread to the soil each week for 4 months.

The compost pile of (4 ft long X 4 ft wide X 4 ft high) was made at the farm in a thermal process using hurricane Fiona wood debris and local grass. A 1:1 Carbon-Nitrogen ratio was implemented in the composting process. The compost was inoculated with Californian earthworm tea, EM and cow manure for bettering the thermal composting process. In a term of a month the thermal compost process was achieved and applied on the field.

At the application 2 cups of EM amendment was spread for each coffee tree. This amendment was made in an anaerobic fermentation using 1-part of Kombucha, 1-part of Molasses, 1-part Californian earthworm casting in 5 gallons of spring water for 21 days in a dark and fresh area.

Research results and discussion:

During the project soil, compost and EM sample were taken to measure fertility and biota. The microBiometer equipment was used to measure compost and EM biota activity.

microBiometer Microbial Biomass Results

Thermal Compost Effective Microorganism (EM)
513 ug C/ g 37.8 ug C/ ml

Fungal:Bacterial Ratio



* (ug C/ g) ug of microbial carbon per gram of soil 

These results demonstrate a normal activity for both compost and EM amendments.  

Plants grown with the compost and EM amendments demonstrated a more rapid and vigorous growth than plants without the applications. Plants without amendments application demonstrated nitrogen deficiencies while plants with applications were more healthy and greener. No pests or disease were noticed on either trial. 

The soil lab analysis demonstrated an increase on soil fertility after the compost and EM applications.


Before compost and EM applications

After compost and EM applications





2.4 meq/100g

1.1 meq/100g

Organic Matter



Estimated Nitrogen Release

196 lbs/acre

332 lbs/ acre


2 ppm 

7 ppm


37 ppm 

157 ppm


159 ppm 

286 ppm


463 ppm 

1297 ppm


27 ppm 

13 ppm

Cation Exchange Capacity 

6.3 meq/100g

10.4 meq/ 100g


20 ppm

10 ppm


1.0 ppm 

5.5 ppm


88 ppm

94 ppm


82 ppm

140 ppm


1.9 ppm

3.4 ppm


0.2 ppm

0.4 ppm

Exchangeable Al (1 NKCl) 

197 ppm

1.63 ppm


Participation Summary
2 Farmers participating in research

Educational & Outreach Activities

10 Consultations
1 Curricula, factsheets or educational tools
5 On-farm demonstrations
20 Webinars / talks / presentations

Participation Summary:

20 Farmers participated
1 Ag professionals participated
Education/outreach description:

A group of 20 farmers from nearby farms were selected to share the practices and results achieved in the project. 10 of these farmers were interested in a consultation of their coffee plantation and how could the compost and EM better their plantations. 5 on farm demonstrations were made as a practice adoption for a more sustainable production. Project factsheets were shared during the visits.

Learning Outcomes

10 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key changes:
  • Plant Resistance

  • Drought Tolerance

  • Soil Structure

  • Microorganism

  • Thermal Compost

Project Outcomes

5 Farmers changed or adopted a practice
1 Grant received that built upon this project
3 New working collaborations
Project outcomes:

This project investigation has helped us coffee farmers study a more sustainable way to deal with climate change problems. In Puerto Rico, mostly on the rural coffee area climate change has impacted many farmers productions. The projects evidence that the use of compost and effective microorganisms can better our soil structure, helping control erosion and drought problems that come with climate change challenges. The soil fertility was improved resulting in a more vigorous plant growth and resistance.

This is a way to better farmers economic returns for the farm production, enhancing the environments and soil conditions and helping farmers achieved a social advantage as they can continue harvesting a quality product from the best practices.

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.