Research aimed at corn production with limited irrigation
As the water goes, so goes agricultural production, especially corn production in the Texas High Plains.
A group of researchers, engineers and specialists are combining forces to help producers develop strategies to continue economically and efficiently growing corn on less water, according to a Texas AgriLife Research scientist.
In the Texas High Plains, corn is a major irrigated crop, and the current productivity is achieved mainly with irrigation from the Ogallala Aquifer, said Qingwu Xue, Ph.D., AgriLife Research crop physiologist and team leader.
"The declining water table, along with irrigation pumping restrictions by water districts, could soon challenge the sustainability of corn production at current levels," Xue said.
The team working to remedy this situation consists of AgriLife Research, the Texas AgriLife Extension Service and U.S. Department of Agriculture-Agricultural Research Service personnel.
"Our study is designed to look at limited irrigation, or the application of less irrigation water than the plants require for maximum production or full evapotranspiration," he said. "We believe this will be the primary practice in the future."
Evapotranspiration is the amount of water lost from soil evaporation and plant transpiration.
This study will focus on management practices that will maximize production and economic return on corn grown using less irrigation than what is required for maximum grain yield, said Brent Bean, Ph.D., AgriLife Extension agronomist.
"Producing maximum yield seldom provides the most economic return, and most certainly is not the most water-use efficient," Bean said. "Those last few bushels require much more water to produce than the first few bushels."
In a preliminary study conducted in 2011, it took 20 inches of water to produce the first 102 bushels of corn, he said. An additional 6 inches of water produced another 95 bushels. Maximum yield was reached by adding 7 more inches of water, but yield was only increased 8 bushels.
"Clearly maximum water-use efficiency was reached at some point well below maximum yield production," Bean said. "And lowering the yield goal where more corn is produced per inch of water will also allow the producer to lower other input costs such as planting fewer seed and applying less fertilizer."
The success of this project can lead to very significant water savings, Xue said. A reduction of just 1 inch per acre per year in irrigation on all the regional corn acreage would result in a total water savings of nearly 40,000 acre feet or 13 billion gallons.
While the team knows the savings can be realized, currently information is lacking to provide producers on best management practices to economically and efficiently produce corn with less water, he said.
This is especially true of the hybrids currently being developed by seed companies and AgriLife Research scientists, Xue said. These new hybrids have more drought tolerance and may yield better than traditional hybrids under limited irrigation.
Bean said the question is, "Do they require different seeding rates and does the planting date need to be changed compared to older hybrids in order to maximize their yield potential?"
Those are some of the management answers the study will provide.
Aflatoxin and spider mites also will be addressed in the study, Xue said, as these can be potential problems for corn production under dry and high temperature conditions.
Drought stress caused by reduced irrigation could accelerate occurrence and damage from both aflatoxin and spider mites, he said. However, the potential impact of either on corn yield, quality and water-use efficiency is largely unknown under reduced irrigation.
"We hope this project can provide critical information for corn producers to manage production risks, maintain sustainable yields and conserve irrigation water," Xue said. "The goal of the project is to lead to sustained profitability, reduced irrigation water use per acre and an increase in water-use efficiency."