A Roadmap to Soil Health
By Wilma Trujillo
Soil heath and quality is a lot like the weather. People talk about it, few understand it, and still fewer do anything about it. At least that has been the case in recent years.
For too long the concept of soil as part of the environment that needs protection has been neglected or misunderstood by the public and policymakers. In the 1970s, we recognized the need to clean up the air we breathe. In the 1980s, we recognized the need to clean up the water we drink. In the 1990s and 2000’s, we acknowledged problems in the soil and started studying specifically soil quality (soil functions)
As stated in the June 1995 issue of Agronomy News, the simplest definition for soil quality is “the capacity (of soil) to function”. An expanded version of this definition presents soil quality as “the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.” In 2013, the Natural Resources Conservation Service (NRCS) redefined soil health as the capacity of a soil to maintain its function and flow of ecosystem services given a specific set of physical, chemical, and environmental boundaries.
With respect to agriculture, the terms soil quality and soil health are used interchangeably to mean “the soil’s fitness to support crop growth without becoming degraded or otherwise harming the environment.
To understand soil health and how cultivation impacts it, we need to define soil. Soil is a heterogeneous natural body. It basically consists of solid particles (mineral particles), organic matter, water and air. Organic matter is one of the smallest components of the soil system, but plays an essential role in maintaining soil health/functions. Soil organic matter is derived from living organisms, such as plants and animals, and their by-products in the soil environment. When organic matter decomposes, it is transformed into different pools as sources of plant nutrients at various degrees of availability and eventually forms humus, the central building block of healthy soil. Therefore, the maintenance of soil organic matter is critical to the health and productivity of the soil; providing a stable soil physical structure for water storage, nutrient exchange with plant roots, aeration and a healthy microbial community will enhance soil health for healthy plant growth.
Four broad principles are used to sustainably maintain or improve soil health: Continue reading