Pioneer, KSU Research Shows No Negative Impact on Corn From Delaying Irrigation

Research provides early-season recommendations, irrigation management tips

DES MOINES, Iowa. – Research from Pioneer Hi-Bred, a DuPont business, and Kansas State University shows corn growers can safely delay the first irrigation without having a negative impact on yield.

A nine-year field study was conducted in northwestern Kansas to evaluate the effects of delaying the first irrigation on corn grain yield and its physiological components. Results from the Pioneer-commissioned study at the K-State Northwest Research and Extension Center in Colby, Kan., confirmed the corn vegetative stage prior to tasseling is the least sensitive to water stress.

“This type of research offers growers the ability to plan irrigation and use only the water needed – avoiding any unnecessary irrigation,” says Freddie Lamm, research irrigation engineer for K-State Research and Extension. “Depending on the subsequent season and irrigation systems, growers could save up to 2 to 3 inches of water.”

Corn proved to be more resilient to early-season water stress than expected, according to findings from the research study. If water stress was corrected by silking time and for the remainder of the season, yields remained unaffected. Fields with limited capacity wells, less than one-quarter inch of water a day, sandy soils and very low winter recharge of water in the soil profile, should begin irrigation at the V4 to V6 stages.

The study was conducted on deep silt loam soil using two Pioneer® brand hybrids and a subsurface drip irrigation system. The corn was planted between late April and early May. The two corn hybrid spilt-plots received six main irrigation treatments in a randomized complete block design.

Irrigation treatments were scheduled as needed by a climate-based water budget. The six irrigation treatments were imposed by delaying irrigation for either zero to five weeks, with the first irrigation treatment June 5 to June 15 and the final irrigation treatment July 10 to July 24. Corn typically begins to silk July 15 to July 20.

The available soil water in the top 4 feet of the soil profile gave the best indication of when to schedule the first irrigation. According to the study, growers can safely delay the first irrigation as late as tasseling when soil water reserves at planting are ample and their irrigation system can correct soil water deficits rapidly.

“This type of research offers growers sound agronoimc advice on how to better manage their irrigation schedules,” says Tom Doerge, Pioneer agronomy research scientist. “The research is particularly valuable to those who are impacted by declining water sources.”

Additionally, there was little or no effect on the grain-filling stage imposed by limiting water to the plant. Final grain yield largely was determined by the number of kernels per acre with little influence of delayed irrigation on kernel weight.

“By delaying the timing of the first irrigation treatment, growers can save time, money and water,” says Doerge.

The study was part of the Pioneer Crop Management Research Awards (CMRA) program that provides funds for agronomic and precision farming studies by university and USDA cooperators throughout North America.