This article is from ECHO Asia Note #15
Soil quality, also known as soil health, is the capacity of the soil to function – how well it fills the roles we need it to, whether in a natural or managed ecosystem. There are a variety of measures used to gauge soil health and although we can use these characteristics as indicators of soil quality, ultimately soil quality is judged by how well it fulfills its functions. Many indicators require complicated and technical lab testing, but many can be carried out with locally available materials as well. Learning about your soil can be a good way to identify appropriate crops for your setting or look for potential problems.
Soil is a complex matrix of inorganic (mineral) particles, non-living organic (comprised of carbon) particles, air, water, and living biota. Soil functions generally fall into five categories: sustaining biological diversity and productivity, regulating water and solute flow, filtering and degrading organic and inorganic matter, cycling nutrients, such as nitrogen and carbon, and providing stability and support. Soils are evaluated in terms of both dynamic and inherent soil qualities; those that vary and do not vary based on use (respectively).
Understanding the many organic and inorganic parts that go into making up the soil can help us develop healthy, productive soil that fills our needs. At the ECHO Asia Seed Bank, we use a number of different production plots with very different site histories, and we were interested in comparing the relative strengths and weaknesses of each plot – both what crops these sites may be best suited for and how to improve the soils present in them.