How to Take the E Out of ET.

Evaporation for irrigated corn grown on bare soil, irrigated twice a week, is 35% of the crop water use. In 2007, Nebraska replaced California as number one in irrigated farmland acres. The number of irrigated acres and rainfed acres in Nebraska and declining groundwater levels and river flows and high variable precipitation are reasons needed to increase the efficiency of crop water use. With crop residue management, controlled traffic and a number of crop management practices one can reduce the evaporation of producing irrigated corn from 35% of the crop water use to as low as 15%. One also saves additional soil water by eliminating tillage. Each tillage operation reduces soil water levels by 0.75 to 2.0 cm. These cropping practices which reduce the E in ET also reduces of eliminates soil losses due to wind and water erosion. Weed population may be reduced as much as 80% using practices which reduce the E in ET. This paper will discuss rainfed, limited irrigation and fully irrigated crop production practices in helping take the E out of ET.