What Is a Soil Profile?

This lab activity aims to introduce the concept of soil profiles and the language used by soil scientists. Through digging up a soil pit and observing different layers/horizons, students can classify and interpret the soil for various uses. Soil horizons, represented by the capital letters O, A, B, C, and E, are used to designate the master horizons, while lowercase letters are used for distinctions of these horizons. Urban soils, however, may not be fully related to natural soil-forming factors and may be manmade layers formed by the deposition of dredge, fill, and/or mixed materials. The activity requires a shovel and tape to collect and display the different soil layers. The soil properties, such as color, particle size, structure, and thickness, can be easily observed, while other properties such as chemical and mineral content require laboratory tests. The activity helps students understand how soil is formed and the factors that contribute to the differences in soil types. It also raises awareness of human activities that affect the soil in urban areas.