1st Lecture on Soil Biology

Here is a short introduction to soil biology and how we will be working with nature to grow coffee.

I did this talk during the Nordic Roaster Forum in 2015. Being the first I have done on soil biology, I am sure there is a lot of details that needs further correction and explenations, but at least it will give you an idea of what we want to achieve with the project.


Methods and applications we use:

Planting shade trees - Helps us recover soil nutrients with their deep roots and leguminous species capture much needed Nitrogen and convert it into nitrates which are used by the coffee plant to grow

Compost - our compost pile is typically 30-40% pasture, 50-60% woody material such as brown straw, brown leaves and wood shavings and 10% cow manure.

Compost extract - as a soil drench to boost the micro organism population in the soil and a bit of organic seaweed as food for the micro-organisms so that they can continue growing in population.

Compost tea - as a foliar application to prevent leaf rust and cover the leaves in good organisms that will feed the plant through the stomates of it's leaves. Compost tea is also an excellent way to grow organisms when we don't have enough compost. It is injected in to the soil or sprayed on the soil around the tree.

Organic pest control - We use Beauveria bassiana (fungal) spores in our compost teas in order to kill leaf cutter ants. These ants eat the leaves off our shade and coffee trees and can wipe out a plantation in just a few days. They use the leaves to grow a fungi that they eat and the only way to get rid of them is to get rid of the queen that lives deep in to their nests in the soil. We use the compost tea to drench the nest and the Beauveria will start to grow on any soft bodied insect. Beauveria can also be used to control the coffee berry borer.

Mulch - We use corse wood shavings on the soil around the trunks of our trees as mulch. This preserves humidity in the soil and increases the fungal biomass in the soil around the trees. 

Cover crops - We are trying to establish a cover crop and have been trying to leguminous plants such as clover and perennial peanut with varying success.

Intercropping - So far we have tried to plant beans, Trephrosia, sun flower, yuca (cassava) and plantain around our coffee trees. None of them have been able to grow well due to dry soils and too much sun. We will be trying more and other crops in the coming years. The idea is to try to establish some temporary shade for our coffee trees until our shade trees have grown up and also to create more organic material and have more roots in the soil to feed the soil organisms.

Seed balls / seed bombs - inspired by Mr Fukuoka and his philosophy. We are mixing clay with compost and a bit of dirt. Then we add water and seeds. The mix of the day is Clover, Alfalfa and Oats. The balls are rolled by hand and will be distributed by scattering them on the top of the soil in our farm before we cut all the weeds to make a mulch/ cover. This will help the seeds sprout and make it easier for the plants to establish themselves. Our farm is still in desperate need of good cover crops to prevent the soil from drying out and eroding. A good cover crop will also suppress weeds and fix nitrogen as both Alfalfa and Clover are legumes.



Soil Food Web


Helpful definitions for readers  

Permaculture: the development of agricultural ecosystems intended to be sustainable and self-sufficient.

Organic: (of food or farming methods) produced or involving production without the use of mineral fertilizers, synthetic pesticides, or other agro- chemicals. However there are products that are allowed that is still harmful for beneficial soil organisms such as copper spray.

Biodynamic: Initially developed in 1924, it was the first of the organic agriculture movements. It treats soil fertility, plant growth, and livestock care as ecologically interrelated tasks, emphasizing spiritual and mystical perspectives.

Nematode: Beneficial nematodes are microscopic, non-segmented worms that attack soil-dwelling insects, eat bacteria and fungi without harming plants. In fact when they poop the nutrients they did not absorb become available to the plants to take up through their roots. There are also root feeding nematodes that feed on plant roots, but they are suppressed in healthy soils.

Cultivar: a plant variety that has been produced in cultivation by selective breeding.

Anaerobic: (in composting) decomposition using microorganisms that do not require oxygen to survive

Note: A Permaculture farmer can be Biodynamic and vise versa. Neither is mutually exclusive but each is unique enough not to confuse with the other.