American Institute of Certified Planners (AICP) Practice Exam

Which of the following statements is true regarding a soil profile?

1. It demonstrates the vertical arrangement of soil layers

2. It includes chemical properties of the soil

3. It reflects only surface soil conditions

4. It is primarily concerned with soil fertility

The correct answer is: It demonstrates the vertical arrangement of soil layers

The statement regarding a soil profile that is true is that it demonstrates the vertical arrangement of soil layers. A soil profile is a vertical section of the soil that reveals the various layers, or horizons, that exist from the surface down to the underlying parent material. These layers each have distinct physical and chemical properties due to weathering processes, organic matter accumulation, and other dynamic environmental factors. Understanding the vertical arrangement is pivotal for various applications, such as land use planning, agriculture, and environmental assessments, as different layers can affect water drainage, nutrient availability, and root penetration. The layers typically include topsoil, subsoil, and parent material, each contributing unique characteristics that influence soil behavior. While the other statements mention important aspects of soil characteristics, they don't accurately define the context of a soil profile. For instance, chemical properties play a role in soil analysis but are not the collective representation that a soil profile provides. Similarly, a soil profile encompasses more than just surface conditions, capturing a whole profile from the top down, and it is not solely focused on fertility, as it also illustrates physical and structural attributes that are crucial in understanding soil dynamics.