Definition of soil: The upper layer of earth in which plants grow, containing organic matter and mineral and rock particles, as well as many living organisms.
Soils vary hugely in composition and this drives their characteristics relating to water holding, nutrient cycling, gas emmissions, plant health and microbe populations.
Good soils provide the basis for abundant vegetative growth, as well as a thriving biological system underground. The health and status of a soil will directly, and significantly, impact the ecology of the area. However, it is very much a dynamic system which can be depleted or revived, and a fundamental principle of regeneration of landscapes, including ecological farming systems, is to build healthy soils.
Soil formation is closely linked to the underlying geology, and this in turn contributes to the characteristics such as drainage and mineral content. The four basic inorganic components are, from largest to smallest, gravel, sand, silt, and clay, which will be present in different proportions…
This is a huge topic, and despite the growing knowledge there remains significant gaps in our understanding of the living system in our soil, although this is changing.
This section introduces some of the major topics and assessments you can do on your own soils…