Soils developed in forest settings tend to have thinner surface horizons than those developed in grasslands.

Soils developed in forest settings tend to have thinner surface horizons than those developed in grasslands.

• A. True
• B. False
• C. Not sure
• D. Sometimes

Answer: (A)

Vegetation type shapes soil horizons through how much organic matter is added and how that organic matter is mixed into the mineral soil. In grasslands, a lot of plant material is produced and the soil is heavily mixed by roots and soil fauna, so organic matter is incorporated into the mineral soil efficiently. That leads to a deeper, well-developed A horizon. In forests, most litter sits on the surface as an O horizon and decomposes more slowly under cooler, sometimes more acidic conditions, so less organic matter is integrated into the mineral soil. Leaching and eluviation under forest conditions can also move material downward, but the surface mineral horizon remains relatively thin. Therefore, soils formed in forest settings tend to have thinner surface horizons than those formed in grasslands.

Vegetation type shapes soil horizons through how much organic matter is added and how that organic matter is mixed into the mineral soil. In grasslands, a lot of plant material is produced and the soil is heavily mixed by roots and soil fauna, so organic matter is incorporated into the mineral soil efficiently. That leads to a deeper, well-developed A horizon. In forests, most litter sits on the surface as an O horizon and decomposes more slowly under cooler, sometimes more acidic conditions, so less organic matter is integrated into the mineral soil. Leaching and eluviation under forest conditions can also move material downward, but the surface mineral horizon remains relatively thin. Therefore, soils formed in forest settings tend to have thinner surface horizons than those formed in grasslands.