The dictionary defines soil as: “the upper layer of earth in which plants grow, or a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.”
But I like to think of soil as a community.
There are three main mineral components of soil: clay, sand, and silt. There's also a little bit of organic matter made from decayed plant and animal material. When organic matter is really really broken down, so it can't decompose anymore, it’s called humus, which shares a root with the word human.
In addition to minerals and organic matter, also in the soil are billions of microorganisms.
Microorganisms are tiny, tiny little life forms, like bacteria and fungi. These microbes, together with the roots of plants, make up the community of the soil.
Just like we humans need to get certain nutrients from our food to be healthy, so too do plants. Plants are sunlight powered to make their own food out of air and water. But just like we can't live healthily off of only carbs, there are some nutrients plants need that they can't get through photosynthesis.
Luckily they've developed a system of exchange with the soil microbes. The microbes are able to break down minerals in rocks or capture nutrients from the air; in this and other ways they get nutrients into forms that the plants can take up. In exchange, the plants feed the microbes sugars.
All this is happening under the soil's surface! This is what happens in healthy soils. This system of cooperation breaks down when the plants stop needing the microbes.
Why would they stop needing the microbes? When we heavily apply chemical fertilizers, the plants get addicted to the quick fix. They are freed from the slow process of relationship building, of having to share.
If the plants are annuals they'll be gone the next year, and the community system will have broken down. The next year's crop will need the chemical fertilizer to do well, because the relationship between plants and soil microbes had suffered.
It will take years to restore.
But degradation is preventable and restoration is possible! It just takes a lot of care, and learning to see crops not simply as products we take out of the land but part of a valuable community. And that all starts with soil: learning to see soil as more than just dirt… you might even think of it as sacred.