James Adkins gave a guest lecture last Wednesday about irrigation. He discussed the various types of irrigation that have been used historically as well as recent developments, such as Variable Rate Irrigation. VRI allows farmers to control the amount of water put out by irrigation over specific areas, improving efficiency and reducing water consumption.
I was surprised to discover that 68% of irrigated land is located in Asia. China and India specifically use a huge amount of their freshwater to irrigate crops, with India using approximately 20% of its electricity to pump water for irrigation.
In the United States, irrigation accounts for 37% of all groundwater used. About half of the irrigation in the U.S. is flood irrigation. Flood irrigation involves flooding a field with water in order to allow the soil to absorb it. This method of irrigation is considered to be inefficient. Flood irrigation is most prevalent in California, where 43% of farmland used flood irrigation.