Leaching is defined as what?

• A. Downward movement of dissolved nutrients through soil.
• B. Upward movement of nutrients.
• C. Lateral movement along the surface
• D. No movement, nutrients fixed

Answer: (A)

Leaching is the downward movement of dissolved nutrients through the soil, driven by infiltrating water. When rainfall or irrigation water moves through the soil profile, it dissolves soluble nutrients and carries them deeper, beyond the upper root zone. This can reduce nutrient availability for plants in the surface layers and potentially transport nutrients to deeper layers or into groundwater. The rate and extent of leaching depend on soil texture and structure: well-drained, sandy soils allow more rapid downward movement, while clayey soils with higher cation exchange capacity hold nutrients better and slow the process. This contrasts with upward movement, lateral movement along the surface, or no movement at all, which describe different soil processes.