Explanation:

There are two main ways that farmers and ranchers use agricultural water to cultivate crops. 

1) Rain-fed farming
2) Irrigation
Rain-fed farming is the natural application of water to the soil through direct rainfall. Relying on rainfall is less likely to result in contamination of food products but is open to water
shortages when rainfall is reduced. On the other hand, artificial applications of water increase the risk of contamination.
Irrigation is the artificial application of water to the soil through various systems of tubes, pumps, and sprays. Irrigation is usually used in areas where rainfall is irregular or dry
times or drought is expected.