Healthy soil means healthy food, which means healthy people! Caring for our soils is caring for ourselves.

A good soil consists of 45% minerals (sand, silt, or clay), 25% water, 25% air, and 5% organic matter. Most soils aren’t naturally like this, but thankfully theres lots we can do to adjust them.The main goal of most soil building is to create more humus, which is organic matter (material that is or once was living) that is decomposed. Humus acts as a literal sponge for nutrients, and the more you have in the soil, the more productive plants will be. Increasing life content (bacteria, fungi, and micro-organisms) is another major goal.

 

Many of our soils are now deficient of most nutrients and fairly devoid of life due to the use of chemical fertilizers. Giving a garden an N-P-K cocktail is like sticking in an IV, the plant is fed a huge supplement of nutrients which it already naturally knows how to receive. Plants receive nutrients by releasing exudates out from the roots, molecules full of starches and sugars to draw in bacteria, who will feed on the them. Protozoa come to feed on the bacteria, and they all release nitrogen as they produce waste from eating and when their bodies decompose after death. Plants even know how to release many different exudates who can attract varying bacteria to bring whatever nutrients they need help with. It’s a system of extreme effectiveness that’s evolved since the beginning of life on earth. When we direct wire a plant a synthetic version of nutrients, the plant stops releasing exudates because it has no need to. But this creates a vicious cycle of addiction, as the plant will keep needing more and more chemicals. Without the abundance of life in the soil that is fed by roots, necessary functions of maintaing that healthy balance of water, air, and organic matter aren’t met, and that leads to nutrient leeching and erosion.

Soil tests are a human-created way to read what’s going on underground, but the soil uses its own language through the presence of weeds. Soil is full of seeds, and when it needs something, it will activate a plant can relieve the negative systems. For instance, mats of creeping buttercup likely means the soil is compacted, as the roots of buttercup are designed to loosen and aerate poor draining soils. Thistles do a great job at extracting silica, so seeing them pop up everywhere means a possible deficiency. We can do our best to listen to the needs of the soil we see from the weeds that pop up and replace the unwanted plants with useful ones that benefit us. In the case of creeping buttercup in compact soils, we could replace a patch of it with black currents, for example, which perform the same function and give us a tasty yield.

 

Composting, mulching, and cover cropping are the key to feeding the soil! We practiced these skills, along with basic soil testing, in the community gardens at Tui.

Other methods we talked about but didn’t get to practice are Hugel Kulture (burying logs under soil to slowly release nutrients and contribute fungus), worm farms (feeding food scraps and human waste to worms in bins to break it down and excrete worm castings, containing quickly accesible nutrients), and leaf moulds (bins full of fallen deciduous leaves, kept moist to develop fungus and turn into almost pure humus).

My knowledge of soil science was greatly expanded as I learned about how and why we need to work with this complex system of life that lies beneath our feet. Nothing excites me more than a handful of rich soil, moist, fluffy, and crawling with creatures!