Soil is complicated stuff. In fact, in my opinion we will never fully understand all of the different processes that happen in the soil, all of the relations, all of the millions and trillions of life forms. But we do have a basic understanding that healthy soil produces healthy plants, which in turn promote health in whatever life forms consume those plants.
We also know that the majority of the soil our food is being grown in these days is basically devoid of nutrition. I’m talking about agribusinesses, monocultures, cash crops (corn, wheat, soy); all grown with chemical fertilizer, herbicides, pesticides, fungicides and for all we know hundreds of other poisonous “cides”. Conventional agriculture sprays all of these toxic chemicals on the food we ingest and effectually kills all of the harmful bacteria, but also ALL of the beneficial bacteria and insects-which in turns destroys birds, frogs, and other animal populations who depend on these insects. So comparing organic/sustainable agriculture to conventional methods is pretty fascinating. In one case we have healthy soil→healthy plants→healthy animals and in the other we have poisoned soil→poisoned plants→poisoned animals? I mean it follows with the pattern that if the soil and the plants are toxic then the end result must be toxic.
Anyways back to soil.
Soil is essentially 50% solid material and 50% pore space (where air and water move through). The 50% solid material is composed of sand, silt, clay and organic matter in different percentages. The surface area of these three elements dictates the behavior of the soil. For example because clay has more surface area water and organic matter stick to its surface and water is held more tightly to the soil. Sand on the other hand holds much less water as you may have already noticed watching waves break on the shore of the ocean, the water seeps through the sand almost immediately.
Healthy soil forms aggregates. These are clumps of soil that form when the proper balance and combination of elements is reached. These aggregates form in the soil and allow macro and micro pores to form. Macro pores are large and water moves through these quickly, and micro pores are small and hold water well. Good soil contains both types of pores.
The ideal loamy soil combination is 40% sand (allows air in, roots breath, soil warms up), 40% silt (happy medium between sand and clay) and 20% clay (holds water). To reach this ideal takes some effort, but the 4th necessary element in our soil can help soil that is too sandy, clayey or otherwise. Meet the amazing stuff we call ORGANIC MATTER. Organic matter provides the glue that helps aggregates stick together, and is composed of live soil organisms that help create pore space and give our soil minerals and nutrition. Between 1-10% of the soil should be composed of organic matter.
A healthy, ideal loamy soil will roll into a worm like shape if you rub it between your hands but will break apart when you drop it. There are several ways to test different aspects of your home soil type, pH, etc but for now I will just provide a few tips:
- Add organic matter. Start a compost pile ( I will provide even more information on compost in later posts), you can add your own compost to your soil to get the right balance.
- Do not walk on your soil—this will compact the pores and not allow adequate water and air to move through the soil.
There are many more tips to come! Next post will focus on Creating a Garden Plan!