Soil Basics

A picture of a soil profile. Soil scientists use soil profiles to study soil and its characteristics. (Photo credit: USDA NRCS Soils).

There is much more to soil than the small mineral particles some refer to as dirt. Soil is composed of mineral matter, water, air, and even organic matter. Each of these soil components has its own physical and chemical properties. The way these components interact together make soil a dynamic substrate in which we grow plants. Changes occurring to soil depth, site, climate, and other factors affect the properties of soil which are conducive to plant growth.

To begin understanding the basics of soil, review the following fact sheets.

Physical Properties

• Soils Basics—Part I, Physical Properties (University of Massachusetts Amherst Extension) is a fact sheet that discusses soil texture, structure, and biological influences.

Texture

Take a closer look at soil texture in the following articles:

• Soil Texture.(NASA and Soil Science Society of America) is a one-page article that helps to visualize the relative particle size differences between clay, silt, and sand.

• Soil Texture: determining soil texture (NASA and Soil Science Society of America) provides a process to estimate soil texture by feel. To determine soil texture, this article asks you to "Use the triangle to determine the soil texture of your horizon." A soil horizon is a layer of soil.

Structure

Take a closer look at soil structure and individual aggregate types or peds:

• Soil Structure (NASA and Soil Science Society of America).

Chemical Properties

• Soils Basics-Part II: Chemical Properties of Soil (University of Massachusetts Amherst Extension). Essential elements, cation exchange capacity, base saturation, soil pH and liming, and buffer pH are discussed here.