Colorado corn study gets to root of issue

New research results on variations in corn root width, depth and density may have an impact on irrigation management decisions, say Mark Sponsler, CEO of the Colorado Corn Growers Association, which is funding the ongoing study.

“These findings can help growers more efficiently determine what kind of watering they should do,” he says of the probe conducted at the Irrigation Research Foundation, or IRF, in Yuma, Colo., for the past two years.

The names and performances of individual varieties are not as important as the discovery of the wide variations in root development that exists for corn plants. The Colorado study offers more information to corn producers about fine-tuning their irrigation.

“More research is needed,” Sponsler says, noting the results from the last two years reflect “new information in what is by far the most comprehensive study of its kind so far.”

Key Points

• Study of corn root architecture in Colorado has significance for producers everywhere.

• Major variations were found in hybrid root development.

• The information can help trigger more efficient irrigation decisions.

The eight varieties studied were hybrids known to be good performers in low-water conditions for northeast Colorado.

Farmers are being called on to tweak their irrigation inputs even further as new demands on limited water supplies continue to mount, Sponsler says. “In the environment into which we are headed, we anticipate the need to know exactly what plants need,” he says. “This study can help determine just that.”

In digs performed at 25, 55 and 100 days after planting, the IRF plots found differences among the varieties. Some roots were deep, some shallow and some illustrated a modified growth pattern.

Maximizing water use

“These varying characteristics definitely tell us that different rooting patterns warrant different management techniques in order to maximize water and nutrient uptake,” says Sponsler. “There are 2- to 3-foot differences between the most shallow and the deepest roots on the different varieties,” he says. “This suggests irrigation efficiency opportunities depending on the soil profile and water availability.”

For one thing, he adds, deeper roots may be able to tap into greater amounts of existing water, while shallow-rooted corn would need more irrigation volume.

“We believe these differences are worth considering in variety selection, deficit-irrigation water conditions and breeding,” he says.

While plant populations seem to matter, they varied by variety and flex vs. semi-determinant vs. fixed-ear characteristics, he explains. “In some instances, the lower populations out-yielded the higher populations of the same variety. Differences in rooting architecture may be a key factor in predicting population responses,” he says.

Results of the study include the following:

Evidence indicates a portion of nitrogen escaped lower limits of root zones due to deep percolation, but heavy rains were a factor in the study.

General shape and depth of the root architecture at 50 and 100 days after emergence provide information valuable to understanding varietal response to differences in water application placement methods.

More research needed

“While our study continues to raise more questions and begs of further investigation, the snapshot we already have of roots in corn plants should be an alert to folks that some significant differences are taking place below ground,” says Sponsler.

The study looked at roots well below the 36-inch level most tensiometers can read, he adds.

The Colorado Corn Growers Association will continue the study at the IRF for at least one more year.

This article published in the January, 2010 edition of IRRIGATION EXTRA.

All rights reserved. Copyright Farm Progress Cos. 2010.