Soil – nutrient storehouse and dispensary, beneficial microbe incubator, carbon sink, flood control program – yes, it’s a resource worth cultivating, so to speak. Its physical characteristics, chemical properties, and its system of living organisms have been the drivers of where civilizations have flourished for most of mankind’s history. With good soil, “just add water” takes on a new meaning. And conversely, poorly managed or “worn” out soils have long been associated with declining societies.
Healthy soil is only about 45% minerals – the rest is air, water, and organic matter. You might think of it as a cake: a cake without much moisture or air would be a pretty sorry cake indeed!So how do you get and keep all that air and water in the soil? It’s all about building and maintaining structure: a framework. In perennial cropping systems this framework is rarely disturbed and can become better over time When it comes to “managed” soils, proper and timely cultivation is crucial to maintaining the physical structure needed so that it can maintain 50% or more air and water. Plant roots will then contribute to the structure as they grow through the pore spaces. It’s a win-win! And the carbon exudates (organic residue, sugars, starches, humus, humin, glomalin, etc) released by the growing plant roots encourage beneficial soil life and improve soil chemistry interactions as well.
The inherent chemical composition of soils is very resistant to change. Elements are not destroyed and the molecules and compounds making up “dirt” are very stable. But the way the chemicals in the soil interact can change – once again, that characteristic is heavily influenced by structure. A once productive soil that is “worn out” is usually one that has poor physical structure, low organic matter content and a corresponding lack of soil life – quantity and quality. Once the the physical structure is restored and the organic matter levels are improved, soil life increases and “Presto” – Good Soil! The desired chemical characteristics have been restored by the action of diverse and numerous soil organisms.
Soil that is well managed and cared for creates a wealth of healthy food in the form of healthy plants and animals. It also supports the adequate supply of raw materials for clothing and building. It is essential to the health and wealth of the human race. This section of Earthwise Academy will attempt to explain and document the science and wonder of what makes a good soil. The major topics below will be addressed in sections and in combination.