Which process moves nutrients through soil primarily with the flow of water, carrying dissolved minerals along?

• A. Diffusion
• B. Adsorption
• C. Mass flow
• D. Transpiration pull

Answer: (C)

Nutrients move with the water flowing through the soil in a process called mass flow. When plants take up water, it moves toward the roots, and dissolved minerals ride along with that bulk movement. This means nutrient delivery depends on how much water is moving through the soil, driven by the plant’s water uptake and transpiration. Mass flow is especially important for nutrients that are highly soluble and not tightly bound to soil particles, such as nitrate and sulfate. By contrast, diffusion relies on concentration differences in the soil solution and becomes more important for less mobile nutrients or when roots are close together. Adsorption is the binding of ions to soil particles and isn’t a transport mechanism, while transpiration pull describes the driver of water movement itself rather than the transport of minerals.