What is the purpose of drainage systems in an irrigation context?

The purpose of drainage systems in an irrigation context is primarily to remove excess water from fields to prevent waterlogging. Waterlogging occurs when the soil becomes saturated with water, which can inhibit root growth, reduce oxygen availability, and lead to poor plant health. A well-designed drainage system ensures that excess water is efficiently removed from the field, allowing for optimal soil moisture levels that support healthy crop growth.

While other options touch on important aspects of irrigation, they do not specifically address the role of drainage systems. Enhancing soil fertility and recycling water usage are important for sustainable agriculture but do not directly relate to the mechanism of drainage. Similarly, distributing water uniformly across crops is pivotal for effective irrigation, but again, it does not pertain to the need for handling excess water, which is the core function of drainage systems.