Soils developed in forest settings tend to have higher organic matter content than those developed in grasslands.

Soils developed in forest settings tend to have higher organic matter content than those developed in grasslands.

• A. True
• B. False
• C. Not necessarily
• D. Depends on region

Answer: (B)

Organic matter content in soil follows from how much plant material is produced and how quickly it breaks down, plus how that matter gets incorporated into the soil. Grasslands typically deliver a large, continuous input of fine roots and aboveground litter that decompose and mix into the mineral soil, building substantial soil organic carbon, especially in well-drained temperate grasslands where Mollisols form. Forests also produce a lot of litter, but a big portion often stays as a surface forest floor and decomposes more slowly in some climates, which can limit how much organic matter ends up in the mineral soil. Because of these dynamics, forest-developed soils do not universally contain more organic matter than grassland-developed soils; in many regions, grassland soils actually have equal or higher organic matter stocks in the mineral soil.

Organic matter content in soil follows from how much plant material is produced and how quickly it breaks down, plus how that matter gets incorporated into the soil. Grasslands typically deliver a large, continuous input of fine roots and aboveground litter that decompose and mix into the mineral soil, building substantial soil organic carbon, especially in well-drained temperate grasslands where Mollisols form. Forests also produce a lot of litter, but a big portion often stays as a surface forest floor and decomposes more slowly in some climates, which can limit how much organic matter ends up in the mineral soil. Because of these dynamics, forest-developed soils do not universally contain more organic matter than grassland-developed soils; in many regions, grassland soils actually have equal or higher organic matter stocks in the mineral soil.