Specific yield is defined as what?

The correct answer is that specific yield is defined as the amount of water drained from the soil by gravity. This concept relates to the capacity of soil to release water due to gravitational forces, primarily relevant in the context of groundwater hydrology and soil science. Specific yield is a critical parameter because it indicates how much water can be extracted from a saturated soil layer, making it particularly important for understanding groundwater resources and the behavior of aquifers.

This definition emphasizes the importance of drainage processes and how different soil textures can influence the amount of water that can be readily removed from the soil after saturation. Understanding specific yield is essential for various applications, including agricultural practices, water management, and designing efficient on-site sewage treatment systems.

In contrast, the total water content in the soil refers to the overall amount of moisture present, regardless of its ability to drain. The soil's drainage capacity during rainfall encompasses a broader assessment that includes both gravity and other factors like soil permeability. Lastly, the water retained by soil after saturation is concerned with the water that remains held in the soil against the force of gravity, which does not reflect the concept of specific yield directly. Understanding these distinctions aids in applying specific yield effectively in environmental studies and engineering practices.