Compost bin at 20° Outside and 100° Inside November 20, 2022
“Egad” you are probably thinking, “He is writing about compost again. Surely his brain is starting to rot.” This article is not exactly about compost but close. In Stevens County we have a “Soil Health Stewards” group hosted by the Conservation Districts. You can check it out or join on Google Groups. ne-wa-soil-health-stewards@googlegroups.com. Recently Greg Deponte posted a link to a video on youtube where Dr. David Johnson and his wife and soil research partner Hui-Chun Su talk about their bio-reactor. This sounds like a science fiction device but there are actually many variations already in use.
I had heard of their bio-reactor before. It has been around for over a decade. But this talk was particularly energizing for me because of all the information they included beyond how to build and use a bio-reactor. I will mention some details about construction but want to start as Dr. Johnson did with some notes on the current health of the world’s soils and their relation to human health. (You can watch the video yourself by searching for “Static Pile Fungal Compost Presentation”.) Here are some bullet points:
- The earth is losing soil at 10 times the rate of soil formation
- One ton of soil per acre is about the thickness of a piece of paper
- 40% of our original topsoil is all we have left
- 60% of the world’s aquifers are being depleted faster than they can recharge
- Farming takes 10 times as much fossil fuel energy as the food energy it produces.
- 70% to 90% of nitrogen and phosphorous fertilizer goes into rivers and lakes.
- We have about 110 documented dead zones (in the ocean) on this planet and they’re all related to the agricultural systems that we’re using right now.
- We have 156 species of herbicide resistant plants.
- In 1975 the chances were about 1 in 5,000 you’d have a child with autism, it’s one in 59 in 2018 (not causation but at least correlation)
- We’ve seen an 80% to 90% reduction in the nutrient values of food
This talk might seem like it is beginning to be one giant bummer. But actually it is just the opposite. Johnson goes on to show that all of these problems are totally unnecessary if we would just start creating soil health with biology instead of chemicals. Not only that but he demonstrates that these methods can increase production 5 to 25 times, even on played out soil.
He takes some time to describe the evolution of biology on planet earth pointing out that microbes have dramatically altered the gases in the air, the carbon in the soil and their own bio-diversity over billions of years. This section emphasizes that diversity, energy efficiency, community and abundance always go hand in hand and evolve to reinforce each other, not just in the world of microbes but in above ground crops as well. Two key points are that microbes can remediate chemically poisoned soil and that the higher the proportion there is of fungi to bacteria, the healthier the soil becomes.
To picture this he sites a common strategy in war. One of the first things combatants try to do is to disrupt the communication and supply lines of the enemy. In the soil, fungi are the lines of communication and supply. Their long hyphae carry signals about supplies and diseases. But they also carry water and nutrients to a plant’s roots multiplying its reach and resources many times. Plowing and tilling break up fungus and degrade the soil. In designing their bio-reactor, Johnson and Su wanted to develop as much fungi in their systems as they could. The key ingredients are lignins (think wood chips, sawdust, grass and leaves) moisture (They shoot for 70%) and air. They want every part of their pile of debris to be no more than 12 inches from fresh air. Manure, vegetable matter and worms are also key ingredients.
Although many composting systems boast that they have thousands of kinds of microbes and nutrients ready to turn back on the soil within 22 weeks, Johnson and Su show that if you wait a full year or more, you get four times as much diversity in the result. It is not a mulch as much as a squeezable clay-like putty. They don’t think of it as a soil amendment or nutrient but as an inoculant. They use it to coat seeds by diluting it with water and wetting the seeds. With just this coating at a rate of 2 pounds per acre, they saw a 5 time increase in production the first year with more each following year, not just on one crop or in a greenhouse, but on multiple kinds of crops from grains to cotton and more and in multiple kinds of soil and water conditions. No minerals or other fertilizers were added to fields in these tests, but nitrogen, phosphorous and numerous other nutrient minerals increased in these soils though the action of biology alone.
Many other things were covered in this presentation but realizing that biology itself is the key to restoring the soil is the major take-away. Thinking about this I looked into how to build a Johnson/Su bio-reactor. This is where the differences between creating a system in California and other warm States and building one in Northeast Washington became apparent. They want the bio-reactor to be filled all at once with 5 gallon buckets of wet leaf mulch or other feedstock, 75 of them. They want it to get to 160° for a few days; have worms added when it gets down to 80°; not freeze for a full year and be watered regularly in small amounts to maintain the 70% humidity. Johnson emphasizes that the challenges are constantly changing and you need to be observant and change with them. This system definitely needs to be reworked for N.E. Washington.
It is 20° or lower outside at night already. I have been amazed that the layers of sawdust and spent wine must in my most recent compost bin are melting snow on top and staying 100° deep inside. I’ve read that you can drive fence posts into the pile then remove them after a few days and the hole they create will keep the air passages open. I’m not sure this is going to give me a squeezable goop after a year, but it’s worth a try.