Regenerating soil organic matter
Plants breath carbon dioxide, taking it out of the atmosphere and returning the carbon to the soil. Plants directly move carbon into the soil both while alive, as exudates which are exchanged with microbes for necessary minerals, and after the plant dies and decays in the soil. Once in the soil, the carbon goes through cycles of life and death as microbe or fungi, soil creature or plant. Most of it re-emerges back into the atmosphere in a fairly short time frame. But some ends up in a form that is no longer food for decay micro-organisms – in a form that is stable for tens or perhaps hundreds of years.
This stable soil organic matter is good stuff. It includes humus and glomalin, the substance that causes soil to clump together, or aggregate. It holds water, a lot of water. It is the essence of tilth, that ephemeral quality of excellent soil.
If we are to regenerate soil, we need to move carbon from the atmosphere and turn it into life. There are a number of ways to do that.
- Do all of the things we talk about on this web site to make plants grow well.
- Grow plants, grow plants, grow plants. This means growing something even if it isn’t a crop. Even if you are just going to mow it down. Plant root exudates are key to building soil carbon and soil life.
- Grow diversity. Communities of seven or more species do much better than a single species, or even a community of six species. Experiment with multi-species in a single plot.
- Don’t till unless you really have to. Tillage is hard on fungi, especially arbuscular mycorrhiza (AMF), the fungi that form associations with plant roots. AMF farms the soil to benefit the plant and it makes glomalin to boot.
- Make the best compost possible to go in the soil. We make bokashi vermicompost, a potent source of nitrogen and life.
- Incorporate livestock into the farm. We know it’s a good idea; we don’t live in a place where it is practical. Worms are our livestock. We encourage you to check out experts on the subject.
- Use the poorly made compost as mulch. The compost that did not heat up, or perhaps still has viable seeds, or isn’t quite done – this is great mulch. This includes most compost you can buy.
- Use mulch where you can. Mulch has so many benefits in terms of keeping the soil moist and providing something for the decay micro-organisms to eat. However, be aware that it can be slug and snail habitat, so use mulch with a fine granularity if this is a problem in your garden.
- Incorporate activated biochar. Well-made biochar is the underlying mineral responsible for the long-lived fertility of terra preta. More on this later.
- Soil is the digestive system of the plant. Appropriate amounts of water and air are necessary for digestion to work. These set an appropriate environment not just for roots to penetrate but for microbes to thrive.
It is the soil biology that really regenerates soil. In order to build the soil biology our soil needs to be an active participant in the cycle of plant growth, death and decay.