What should you observe when identifying soils?

• A. Soil colour
• B. Groundwater level
• C. Vegetation type
• D. Slope direction

Answer: (A)

Soil colour is a key field observation because it reveals important information about the soil’s composition and drainage history. Dark colours typically indicate higher organic matter content and moisture retention, while red or yellow hues come from iron oxides and suggest well-drained, oxidizing conditions. Gray or mottled colours indicate periodic waterlogging and reducing conditions, which affect permeability and root growth. These colour patterns help identify soil horizons and overall soil suitability for applications like septic system absorption areas, since they relate to texture, structure, and drainage.

Groundwater level, vegetation type, and slope direction are informative about the site environment but do not directly identify the soil’s material properties the way colour does. They influence how soils form and function, but colour is the most immediate telltale sign of soil characteristics.