Answer to Question #3:
The answer is D. Ideally corn would use 23.7 inches of water during the average year in central Iowa. Because soil water is not always readily available, the actual average water use is 21.9 inches, which results in some yield reduction because of water stress. In southwest Iowa the ideal water use is 25.1 inches and in the northeast district the water ideal is 22.7 inches.
webmaster@exnet.iastate.edu