How Organic Material from Forests Can Improve Soil Health

Zarcero, Costa Rica – Henry Guerrero is a pioneer of organic agriculture in the mountains of Costa Rica. For decades, he has been implementing sophisticated fermentation techniques that incorporate organic material collected from a forest at the farm. 

In his biolaboratory at Finca El Guerrero, Henry cooks up precise recipes in a series of tanks – beginning with organic material collected from the forest floor. At the heart of it all is the health of the soil. The preparations he makes are designed to provide the soil with essential microorganisms and nutrients, boosting soil health and leading to healthy crops that nourish the local community. 

“For me, the secret [to being] a farmer is knowing how the soil recovers,” Henry says. 

Henry has been farming since he was 18. Several decades ago, he participated in a course led by Shogo Sasaki, an organic farmer from Japan, that dramatically changed his approach to farming. Before that course, Henry had already been trained to use techniques such as contour planting – a conservation practice designed to reduce soil erosion by enabling the soil to absorb more runoff. He had also learned how to use herbicides. Sasaki’s teachings incorporated organic techniques that allowed Henry to transition away from using herbicides.

Henry’s Tips for Collecting Forest Material

• Go into the forest and observe your surroundings, including the types of trees and other plants that are growing in the area. Look for plants that produce large amounts of organic matter, such as bamboo and caña brava, or wild sugarcane. 

• If there is a layer of leaves on the ground with decomposing leaves underneath them, that’s a great sign. 

• Taking small amounts of this organic material, including pieces of small branches or sticks, doesn’t harm the forest. 

“From the forest, I'm taking the source of biology to bring it back and start working with it, fermenting it, and multiplying it. It's used as a base,” Henry explains, adding that the forest floor contains both prebiotic and probiotic microorganisms. The fermentation process is based on techniques used to ferment and preserve food in Japan and other cultures before electricity was available, he says. 

Fermentation Process

During this phase, Henry also adds other ingredients such as ground rice, corn or wheat, additional microorganisms, and minerals. He also adds molasses and sugar cane to create a rich, amber-colored liquid mixture that gently bubbles and smells sweet. The sugar cane is cleaned without bleach to avoid harming the beneficial microorganisms in the mixture, which is later applied to the soil in the areas he cultivates. 

“It’s a very beautiful subject of patience, perseverance and rigor,” Henry says about his work in the biolaboratory. 

Henry's Agricultural Legacy

Henry’s children are also carrying on his farming legacy. As they grew up, he intentionally involved them on the farm, and his oldest son is now an agronomist. His 19-year-old daughter also works in the family-run bakery near the farm and is planning to study agronomy when she enters university.