… and making compost that will do that!

Scott with full bioreactor and ventilation placeholders

As my own way of addressing the climate challenge in retirement, I am making, sharing and applying a particular form of compost called fungal dominant compost (FDC). My teacher through YouTube has been Dr. David Johnson and I have developed a composting method partly based on his Johnson-Su model. There are many ways to make compost but for the purposes of introducing you to FDC, I will make a direct comparison of it to typical municipal compost made from yard waste.

FDC is a soil inoculant which can reintroduce a diverse army of fungal microbe workers into degraded soils whose normal fungi have been deeply reduced by fungicides, excessive fertilization and tillage.

How is FDC different from regular compost? FDC and conventional municipal windrow compost appear very similar, with the main differences being related to disturbance, temperature and digestion time as they are produced.

In conventional windrow composting, yard waste (and kitchen waste) biomass are chopped, mixed and turned repeatedly to oxygenate, rewet, homogenize and generally keep the decomposition process hot and quick.

A bioreactor ready for filling

While I use chopped, wetted, Fall leaves to make a leaf-mould FDC compost, it can be made from other forms of biomass placed gently in a wire mesh bioreactor with vertical natural chimneys to assure an oxygen supply to all parts of the pile. This composting process is slower, cooler, and static. The finished compost it produces is well cured and decomposed. This passively aerated, static system design has only one initial, moderate temperature, short duration thermophilic heating cycle. Gaseous emissions and water loss are reduced. Airborne fungal spores arrive and have their influence during the elongated cycle of decomposition. Non-disturbance for 12 to 24 months allows this compost to gradually become fungal dominant. Worms, if introduced into the biomass, enhance this development.

Aerial view of ventilation chimney caps

In windrows, the conventional compost pile will heat up repeatedly and reach temperatures of 55 to 80°C. At those temperatures, fungal growth is stunted and the main microbial decomposing processes are performed by bacteria. Windrows cool down gradually until they are turned/mixed again, which will spur another round of heating. Conventional compost is often used before it is fully cured (decomposed) driven by limited facility space as new biomass arrives continuously. This haste can lead to issues with phytotoxicity, toxicity which inhibits the growth of plants. The high temperatures and mixing also result in losses of water and nutrients, particularly nitrogen, through volatilization. More info.

Fungi are one of the most important and least understood members of the soil biology workforce. They are co-workers with bacteria, worms, protozoa, nematodes, archaea…etc. In the cycle of life, fungi are the decomposers. Soils with healthy levels of diverse fungi can hold more water and reduce the likelihood of plant stress in drought situations.

The finished product

Leaf-mould, which is one form of FDC, can retain 300 to 500 percent of its weight in water, compared to rich topsoil, which holds 60 percent of its weight. Foods grown in microbially healthy soils deliver higher nutritional density. Fungi contribute to weed and disease suppression. Fungi provide many of the services in soil that we over-ride when we resort to synthetic fertilizers and biocides. Fungi also play a central role in building persistent carbon levels in soil. 

How can I apply FDC to a plant or into soil? It is surprisingly easy. A compost extract can be made with 1 litre of FDC in 4 gallons of water, stirred vigorously. Seeds can be coated with this extract. It can also be sprayed on leaves, in a furrow, sprinkled or sprayed at the root zone of a seedling or a transplanted tree, or used to drench existing grass.

Whereas fertilizers and bacterial compost are largely consumed as food within one growing cycle, FDC, as an inoculant, primes or sets in motion a biological process which continues by degrees for as many years as the soil is managed regeneratively. 

Find out how to be an FDC Citizen Scientist at ONfungi.net

Scott Hortop, Senior Soil Carbon Advocate

4925 March Road, Almonte, Ontario

647 637 8838    F.R.Scott.Hortop@gmail.com

Putting Fungi to Work in Your Soil: