Spray irrigation of an alfalfa field in Central Greece. Spray irrigation is a method for disposing of secondary treated municipal wastewater by spraying it on the land surface. The sprayed wastewater either evaporates into the air, soaks into the soil, or percolates through the soil and recharges the ground water. Alfalfa is a source of vitamins A, C, E, and K4, and minerals calcium, potassium, phosphorous, and iron. Alfalfa is a perennial flowering plant in the pea family Fabaceae and is cultivated as an important forage crop. The rainbow here is caused by refraction of the water droplets falling from the sprinkler where the sun is behind the drone.