Soil

From Envirowiki

Soil is a substance that lies on top of the earth's crust, and is made up of minerals (rock, sand, clay, etc.), as well as all types of living organism, and dead organic matter. Soil is generally considered "healthy" when it has a high diversity of biotic content, as this shows that levels of toxics are low enough, and nutrients and water levels are adequate.

Soil is the basis of all rich ecosystems, and is created in a positive feedback cycle, where the existing life forms help to reduce toxicity levels, then die, adding hummus and non-living organic matter to the existing soil. This process fortifies the soil's nutrient levels, and its ability to store water.

Composting replicates this natural process, and can help to make damaged soils healthier.