Irrigation Sunset
“Since 2009, there has been a strong educational outreach, and water conservation efforts, to make producers aware of the aquifer situation across the Mid-South,” says Lyle Pringle, researcher at the Mississippi Agricultural and Forestry Experiment Station. “The goal is to ensure that the Delta will have water now and in the future.”

Irrigation: A game-changer for Mid-South agriculture

“The goal is to ensure that the Delta will have water now and in the future.”

1980 was a pivotal year for agriculture in the Mid-South. After a relatively wet June, the rains stopped across most of the region for all of July and well into August, and temperatures soared to 105 and 106 for days on end.

The drought that year brought a renewed interest in irrigation for the region’s cotton and soybean growers. Some even purchased and moved older, pressure-driven center pivot systems from Nebraska to the Mid-South in preparation for 1981.

More dry weather in ’81, and the growing popularity of catfish farming in the Mississippi Delta in the early 1980s, led growers to put down hundreds of new irrigation wells into an alluvial aquifer that seemed, at the time, to promise an unending supply of water. 

Researchers like Lyle Pringle remember the intense interest in watering crops. “The Delta Research and Extension Center obtained its first lateral move irrigation system in the 1982 growing season,” recalls Pringle, an Alexandria, La., native who earned bachelor’s and master’s degrees at Louisiana State University, and began working for Mississippi State University in 1982. 

“Producers began putting in pivot systems in 1980 and 1981, because 1980 was hot and dry, and 1981 was dry but not as hot. We put in a second lateral move system at Stoneville in 1984 because growers were wanting more answers about irrigation.”

‘A STRONG PRESENCE’

In one of the first irrigation studies, Pringle remembers Mississippi State University researchers hand-picking 40 feet of cotton at four locations, inside and outside of 40 center pivots located throughout the Delta region. “So, there was a strong presence of pivots by 1984,” he says.

Other land-grant universities began hiring irrigation specialists to try and get a better handle on how to best water crops. Phil Tacker, a young agricultural engineer, joined the University of Arkansas Extension Service in 1982.

Although the advantages of irrigation were obvious in drought years like 1980 and 1981, irrigation specialists had to work through ideas such as the one that cotton should be stressed to promote fruiting or, at the other end of the spectrum, that there was no such thing as too much irrigation.

“When pivots were prevalent across the landscape, it was not uncommon in some years to hear that producers were making more cotton outside the pivot than underneath the pivot,” says Pringle. “Irrigating too early, when there is still sufficient soil moisture in the profile, or an irrigation plus rainfall and several days of cloudy weather, can result in reduced yields by encouraging rank growth, shading within the plant, and abortion of flowers and young bolls.”

Tacker and other University of Arkansas researchers began to work on scheduling programs to help growers better time their irrigations. Sometimes it was something as simple as making checkbook deposit entries for a rainfall or irrigation event, and withdrawals when evapotranspiration occurred on hot summer days.

ADVENT OF POLYPIPE

As the 1980s continued to be hotter and drier than previous years, growers began to take another look at their irrigation systems. The need for improved drainage and the advent of flexible irrigation tubing or polypipe led many to level their fields with the idea that they could roll out the plastic film when they needed to irrigate. 

“The dry years spurred the move to more irrigation, coupled with the introduction of pivots and then polypipe, which made irrigation less labor-intensive, as compared to furrow irrigation with gated pipe,” Pringle says. “Then, in the 1990s, precision land grading with lasers allowed them to expand their furrow irrigated acreage even more.”

As farmers shifted to more corn and soybeans, many producers perceived that the nozzle packages on the pivots were not sufficient. “Most pivots in the 1980s were designed to apply 0.25 inches per day, when run continuously, whereas today they are designed for higher application rates,” he says. 

“The perception of pivots not being able to supply enough water, along with having to deal with non-irrigated corners, pivots getting stuck, and electrical issues, was such that when it was time to make a change with their aging pivot systems, many producers have chosen to precision land grade and furrow irrigate with polypipe.”

Meanwhile, irrigation specialists such as Tacker and Jim Thomas with Mississippi State University Extension Service were urging growers to monitor soil moisture with a soil probe or moisture sensor, and to make sure they had sufficient irrigation capacity to get around to all their fields in a timely manner.

“Jim Thomas was from northeast Arkansas, and then worked a few years in Kansas before coming to Mississippi,” says Pringle. “From working in those different locations, he knew the value of irrigation.”

Tacker and Thomas, both known for traveling their states tirelessly and working face-to-face with Extension agents and growers, conducted meetings and on-farm field days to help growers make better use of their water and their irrigation systems.

DECLINING WATER TABLES

Meanwhile, Earl Vories and Joe Henggeler, agricultural engineers with the USDA Agricultural Research Service and the University of Missouri, respectively, were working with growers in the Missouri Bootheel and northeast Arkansas on similar projects.

Each of them also recognized the growing problem with declining water tables across the region, a result of the irrigation demands of Arkansas’ 1 million-plus acres of rice and Mississippi’s rice and 100,000 acres of catfish ponds.

In 1989, the Mississippi legislature created the Yazoo-Mississippi Delta Joint Water Management District, tasked with creating a permitting system for irrigation wells across the state to try to conserve water supplies.

“Interest in water savings has been fueled by concerns over the mining of the aquifer and potential government intervention, while energy and time savings have been the drivers of adoption of these conservation practices,” says Pringle. “Unfortunately, as crop prices weaken producers may find it more difficult to fund some of these practices if payback is not immediate.”

Dean Pennington, professor of agronomy at Mississippi State who became the YMD’s longtime director, helped monitor water use through the permitting system and by providing information about water-saving technology.

SOFTWARE TOOLS

In the 2000s, the arrival of irrigation specialists, such as Drs. Jason Krutz at the Delta Research and Extension Center at Stoneville, Miss., and Chris Henry at the University of Arkansas, also helped growers to make greater use of computer tools such as the PHAUCET program and Delta Plastic’s Pipe Planner software.

Krutz, a native of Blytheville, Ark., conducted many on-farm demonstrations in which he used surge valves to improve the movement of water across furrow-irrigated fields, and Henry helped many growers improve pumping efficiency for their irrigation systems. 

“Mississippi, where furrow irrigation is a common practice, is the leading state in adoption of computerized hole selection (Phaucet or Pipe Planner), thanks to research and Extension efforts, along with industry support,” says Pringle. “Adoption of moisture sensors and surge valves is not as widespread, but has grown over the last few years.

“Some agricultural consultants and irrigation companies are offering irrigation services, where they install and monitor soil moisture sensors for producers. Adoption of these practices is more likely when a producer has seen it work on his farm.”

Dr. Stacia Davis, Extension irrigation specialist for the LSU AgCenter, has been working with moisture sensors to determine the impact of cover crop and tillage practices on moisture availability in Louisiana fields.

NEW FLOODING METHODS

Some of the biggest strides are occurring in rice, where researchers such as Dr. Joseph Massey, who now works with the USDA Agricultural Research Service Delta Water Management Research Unit at Arkansas State University, have developed new approaches to flooding the crop.

Massey’s work with Multiple Inlet Rice Irrigation (MIRI) systems while he was with the Yazoo Mississippi Delta program helped provide major savings in water and irrigation costs at a time when rice prices have been low around the world. 

Dr. Michele Reba, research leader for the USDA-ARS unit, is conducting trials across northeast Arkansas aimed at reducing water usage and helping growers make use of markets for carbon credits.

“Since 2009, there has been a strong educational outreach, and water conservation efforts, to make producers aware of the aquifer situation across the Mid-South,” says Pringle, who continues to work as a researcher for the Mississippi Agricultural and Forestry Experiment Station.

He points to the establishment of a volunteer metering program, at the 10 percent level of participation, by the Governor’s Delta Sustainable Water Resources Task Force, which brings several organizations together to develop and promote implementation of consensus-based solutions.

“The goal is to ensure that the Delta will have water now and in the future,” he says. “All these combined efforts show that more producers are aware of the problem, especially with the perceived uncertainty of available water in the future.

TAGS: Water
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