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Module 1: Quality Soil

Soil Contains What...?

Soil is: "A collection of natural bodies which have been synthesized in profile form from a variable mixture of broken and weathered minerals and decaying organic matter, which covers the earth in a thin layer, and which supplies, when containing the proper amounts of air and water, mechanical support and sustenance for plants."


There are four major physical components in soils. They are:

  • Mineral Matter
  • Organic Matter
  • Water (soil solution)
  • Air (gases)

This entire course is about how these four components interact to affect plant growth and surface playability.

Mineral Matter

shovel full of soil

Mineral matter is the solid portion of the soil that isn't and never was alive. Mineral matter is quite variable in size and composition. It ranges in size from small rock fragments of various kinds to colloidal clay which can only be seen using an electron microscope. The relative amounts of the various size particles determine the soil texture. The soil particles may act independently or form aggregates or groups of particles. The arrangement and degree of this association or aggregation determine the soil structure. These aggregates vary from granules to plates, blocks, or columns. Both soil structure and texture influence water and air movement in the soils.

Turf 235 Review: Soil Structure and Texture

At this time it might be a good idea to review the sections on soil structure and soil texture from Turf 235 (Courtesy of A. J. Turgeon).

Soil Properties soil environment

Soil serves as a medium for supporting plant growth and development. Its properties influence fertility, water relations, gas exchange, and physical support of plant roots. For turfgrass plantings, the soil and plant community should also provide a firm, but resilient, surface that resists compaction from traffic and use.

diagram showing the combination of solid particles and pore spaces that make up soil

A soil is a combination of solid particles and pore spaces. The particles may be composed of mineral or organic matter. The pores may be filled with water (and dissolved substances) or air.

image of ideal soil. ideal soil is well aerated, neutral to slightly acid pH, and contains ample water and nutrients

An ideal soil is well aerated to ensure that oxygen is not limiting to the growth and function of roots and soil inhabiting organisms. Its pH is slightly acid to neutral to limit the availability of toxic elements and to promote the availability of essential nutrient elements. And it contains an ample supply of plant-available water and nutrients.

soil science is made of two major branches - soil physics and soil chemistry

The two major branches of soil science are soil physics and soil chemistry. Soil physics deals with the physical properties of soils while soil chemistry deals with their chemical properties.


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