What does field capacity refer to?

• A. The maximum water retention of soil
• B. The moisture content at which soil is saturated
• C. The total amount of water stored after gravitational water has infiltrated
• D. The water content before rainfall occurs

Answer: (C)

Field capacity is understood as the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. It represents the point at which the soil is fully saturated with water but not so saturated that water is freely draining under the influence of gravity. This state allows for optimal conditions for plant roots to absorb water.

The correct answer reflects that field capacity represents the total amount of water stored in the soil after gravitational water has moved through and is no longer part of the freely draining water. This is a crucial concept in landscape management, especially when considering irrigation practices and soil health.

Other choices reference related soil moisture concepts but do not accurately describe field capacity. For example, maximum water retention of soil might refer to the soil's overall potential to hold moisture, while the moisture content at saturation refers to a different point when all soil pores are filled with water. The description of water content before rainfall is not relevant to field capacity and instead relates to pre-existing soil moisture levels. Understanding field capacity helps in making informed decisions about irrigation needs and managing water resources effectively in landscaping.