“The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no community, because without proper care for it we can have no life.”
― Wendell Berry, The Unsettling of America: Culture and Agriculture
As a Turfgrass Warrior, you must have a thorough knowledge of soil. It is our operating environment. In today's battlespace, information on soil is considered as important as any weapon system. For this briefing, soil will be defined as: “That portion of the earth’s crust made up of mineral materials, organic matter (living and non-living), water, and air, that is capable of supporting plant growth." As soils develop, they usually form horizontal layers. A soil profile is a vertical sample cut that shows the layers – called horizons. There are four principle horizons – 0 through C – up to parent rock. See the soil horizons above. (Procedures for Soil Analysis, VanReeuwijk, 1995)
O) Organic matter: Litter layer of plant residues in relatively un-decomposed form. (There’s your thatch. More on that later.)
A) Surface soil: Layer of mineral soil with most organic matter accumulation and soil life. This layer eluviates (is depleted of) iron, clay, aluminum, organic compounds, and other soluble constituents. The A-horizon is regarded as a "biomantle".
B) Subsoil: This layer accumulates iron, clay, aluminum and organic compounds, a process referred to as illuviation.
C) Parent rock: Layer of large unbroken rocks. This layer may accumulate the more soluble compounds.
Therefore, soil has four components: mineral materials, organic materials, water and air. The mineral component is inorganic (lacking the element carbon) and has three types of particles: sand silt and clay. Soil “texture” refers to the size and relative proportion of each of these particles in the soil.
The organic component of soils usually ranges from 1 to 8 percent. Also called humus, the organic component has this decomposed organic matter. The organic matter also contains fungi, bacteria and organisms.
Water is taken up by turfgrass by its root system. Soil holds water and air in its pores. The texture and structure of the soil can determine the amount of water is available for uptake by the turfgrass.
Air fills the pores not filled by water. Turfgrass roots need soil oxygen for the uptake of water and nutrients and for growth. Soil micro organisms and other soil inhabiting organisms need oxygen for normal metabolic processes.
Understanding the soil in your AO (Area of Operation) is critical to mission success.