Final answer:
Irrigation is the method of supplying water to crops to assist growth, often essential in turning arid regions into productive farmlands and crucial for sustainable agriculture and water conservation.
Step-by-step explanation:
Irrigation is the process of supplying water to land or crops to help them grow, typically by means of channels from rivers or other water sources. In areas such as California's Central Valley, irrigation transforms otherwise arid land into highly productive farmland. Moreover, irrigation systems, like those in medieval Egypt, were integral to the rural economy, impacting food production and livelihoods. Efficient irrigation practices, such as the drip systems used in Israel, are also crucial for water conservation and sustainable agriculture.