MANHATTAN, KANSAS – A recent field study shows irrigating corn fields before planting increases yields.

The study was conducted from 2006 to 2009 by the Kansas State University Research and Extension Southwest Center and showed preseason irrigation treatments increased overall corn yields by an average of 16 bushels per acre. It also found that both crop water use and water use efficiency tended to increase with well capacity and preseason irrigation.

Alan Schlegel, agronomist-in-charge at the Tribune Unit where the study was conducted, said optimum plant populations also varied with irrigation levels.

"A plant population of 22,500 plants per acre was adequate with the lowest well capacity and without preseason irrigation," he said. "However, if preseason irrigation was applied, a higher plant population increased yields even at the lowest well capacity."

The study evaluated three different plant populations at preplant irrigation levels of 0 and 3 inches and at well capacities of 0.1, 0.15 and 0.2 inches per day. Soil water measurements were taken at regular intervals throughout the growing season. Crop water use was calculated by adding soil water depletion and in-season irrigation and precipitation, while water use efficiency was figured by dividing grain yield by crop water use.

SOURCE: Kansas State University Extension