Define soil water holding capacity.

• A. The soil’s ability to retain water for plant use
• B. The soil’s drainage rate
• C. The rate of rainfall infiltration
• D. The soil’s salinity

Answer: (A)

Soil water holding capacity is the soil’s ability to retain water that plants can use. After excess water drains away, the remaining water between field capacity and the wilting point is what plants can actually access. The amount of this available water depends on soil texture and structure: clay and organic-rich soils hold more water because they have more surface area and smaller pores, while sandy soils drain quickly and store less. This concept is different from how fast water drains from the soil (drainage rate), how fast water enters the soil (infiltration rate), or the salt content of the soil (salinity), which can affect plant water uptake but aren’t about how much water is available to plants.