Final answer:
True, grassland soils generally have higher organic matter than forest soils because grasslands contribute extensively to the soil through their root and surface biomass, creating much thicker A horizons.
Step-by-step explanation:
It is true that soils developed in grasslands tend to have higher organic matter than those developed in forest settings. Grassland soils often exhibit much thicker A horizons with significant organic matter content resulting from both their root systems and the surface biomass that is returned to the soil annually. Forests contribute leaf litter to the soil surface, leading to a rich, organic layer over time; however, in grasslands, this effect is amplified due to both the root and surface mass of grasses. Additionally, grassland soils are typically considered more agriculturally productive than forest soils.