What is the primary purpose of irrigation in agriculture?

The primary purpose of irrigation in agriculture is to supply water to an area of land. This is essential for growing crops, as water is a critical component for plant growth, allowing them to absorb nutrients from the soil and perform photosynthesis. Adequate water supply ensures that crops can thrive, especially in regions where rainfall is insufficient or unpredictable. Irrigation systems are designed to deliver the precise amount of water needed to maintain optimal moisture levels in the soil, which in turn supports healthy plant development and maximizes agricultural yields.

While the other options relate to important aspects of agricultural practices, they do not capture the core function of irrigation. For instance, draining excess water from fields is essential for preventing waterlogging but is an aspect of water management rather than irrigation itself. Improving soil structure may result from proper irrigation practices, but it is not the primary goal of irrigation. Cultivating alternative crops can be a result of various agronomic decisions but is not directly tied to the function of irrigation. Therefore, supplying water is the fundamental role that irrigation plays in supporting agriculture.