Acres Under Water

Improvements in Delta irrigation make a difference, other areas slow down

Story by Nancy Jorgensen

Despite wet conditions much of last year, irrigation paid off for farmers in Missouri and surrounding states, according to Joe Henggeler, who conducts an annual survey of Bootheel irrigators.

Our most significant finding is that bedding up [for furrow irrigation] is important to improving yields, whether you’re irrigating or not,” said Henggeler, Extension agricultural engineer at the University of Missouri’s Delta Research Center in Portageville.

“Using a scheduling tool to irrigate also yields good results,” Henggeler added. Over the years, farmers have increased use of schedules that chart optimal timing of irrigation for specific crops, existing moisture and soil type. The survey shows that only 19 percent of farmers use a scheduling tool—but they use scheduling more frequently for corn and soybeans than for cotton. Tools available include the Arkansas Scheduler computer program and Woodruff charts (see Web site at the end of this article).

Even if irrigators don’t use schedules, many benefit from observing neighbors who do. “Farmers watch their neighbors and they can tell who does a good job,” Henggeler said. He knows growers are learning better methods because they yield 25 bushels more of soybeans when irrigating today, compared to improved yields of just 11 to 13 bushels over dryland methods in earlier years of the survey.

It’s no surprise that irrigation improves yields. Henggeler’s 2008 survey showed that irrigation yields beat dryland by 54 percent for corn, 57 percent for cotton, 61 percent for single-cropped soybeans and 81 percent for double-cropped beans. The yield advantage decreased when you look at the average for 1987 to 2008, again indicating that farmers learned better methods in recent years.

Pivot and furrow costs comparable

About 59 percent of Bootheelers use pivot, while the rest use furrow. Last year, Henggeler believed that furrow irrigation was more cost efficient in the Bootheel, where water lies close to the surface, making it cheaper to pump. Now he thinks that if you’re irrigating Delta land that’s never been irrigated before, the up-front expense of pivots runs about $375 to $400 an acre, similar to the cost of land leveling and other expenses associated with furrow. At least that’s true for soybeans if you plant on beds under pivot. “The cost doesn’t differ as much as I thought,” Henggeler admitted.

Pivot costs compare with furrow in the Bootheel, but furrow irrigation won’t work in other parts of Missouri or surrounding areas. Furrow success depends on water being close to the surface. As Henggeler points out, you must dig deeper to hit water in irrigation areas like Audrain County, Mo., where it might cost up to $80,000 to sink a deep well compared to about $6,000 for a much shallower well in the Bootheel.

Once irrigation systems have been installed, ongoing expenses run about the same. “Pivot requires much more energy, but furrow can be more inefficient in terms of pumping, depending on variations in the water table,” Henggeler said.

The average irrigator surveyed spends $8.68 per acre to maintain and repair irrigation systems. While the cost of energy needed to pump water dropped in 2009, last year the most common fuel, diesel, cost $32 per acre; electric, in second place in terms of use, cost $20; and LP gas, $22.

In addition to analyzing survey results, Henggeler also downloads satellite photos of the Delta region from Google Earth to estimate acreage irrigated. He was surprised to see that about a quarter of pivot circles are incomplete, probably due to property lines or buildings cutting into fields. This brings up another consideration.

“Capital investment costs for a pivot are the same whether you run it in a full or a half circle,” he said.

“If you’re only able to use half of the circle, your per-acre investment costs double.”

Satellite maps confirm that irrigation continues to grow in the Delta. Henggeler also observes growth in the number of fields being laser leveled, pivots sold and new wells dug.

Irrigation growth varies

While Henggeler’s survey reaches a small sample, his results track with USDA’s Census of Agriculture, which reports on more irrigators.

Henggeler estimates at least a 3 percent annual growth in irrigated acres in Missouri. About 80 percent of the irrigated acres in the state are found in the Bootheel, but farmers also irrigate in north central, northwestern and other pockets. USDA’s recently released census for 2007 showed 3,613 Missouri farmers irrigate, an increase of 9 percent from 5 years earlier, but Henggeler believes USDA doesn’t count all the irrigators out there.

While Delta acres may be expanding, growth in the nation and the world may be slowing. Dirk Lenie, vice president of marketing and export sales for Lindsay Corp., manufacturers of Zimmatic pivot systems, reports that while sales boomed in 2008, Lindsay suffered a significant decline this year, prompting the Omaha-based company to reduce its workforce in response to lower demand.

“We’re still profitable, but farmers are holding onto their money right now,” Lenie said. “The drivers have not gone away—there’s a greater need to conserve water, and pivot automated systems use less water and less fertilizer.”

Nationwide, the USDA census Irrigation Survey, last compiled in 2003, revealed that of 53 million acres irrigated, 40 percent were pivot, 44 percent gravity flow, with the balance covered by other methods. Results of a 2007 census are expected later in 2009.

A few irrigation statistics can be gleaned from the overall 2007 ag census. It shows higher farm production expenses on irrigated acres in Missouri than on nonirrigated, but irrigators made a bit more on their investment.

Farm production expenses totaled $1.0 billion in 2007 on irrigated acres, or 17 percent of total expenses on all farmland (not just cropland) of $6.1 billion. By comparison, irrigators made 18 percent of the market value of all products sold, or $1.4 billion of $7.5 billion.

For more information, including irrigation schedules, visit the University of Missouri’s agricultural education site, http://agebb.missouri.edu, and click on Missouri irrigation.

Delta Center breaks new ground with pivot-irrigated rice

Farmers grow 3 million acres of rice in the U.S., with 200,000 acres of them in Missouri—virtually all in the Bootheel along the Mississippi River, where water is plentiful. Rice growers traditionally use flood irrigation, but a new project started last year at the University of Missouri-Delta Research Center is experimenting with a center-pivot irrigation system.

“We had a steep learning curve last year,” said Gene Stevens, extension crop production specialist at the Delta Center. “Often agricultural research involves tweaking an existing production system, but this research is truly breaking new ground.” Stevens is cooperating with Earl Vories, USDA-ARS, and Joe Henggeler, both irrigation engineers at the Delta Center.

In 2007, the pivot-irrigated rice used 30 percent less water than a neighboring flood-irrigated field, Stevens said, but rice farmers must produce high yields for pivot rice to be accepted. “It’s all about yield and price,” he said. Using a single application of dry urea nitrogen, rice only produced 90 bushels per acre. But yields climbed to 175 bushels when the same amount of nitrogen was split into five applications in weekly intervals using fertigation.

Fertigation involves injecting liquid fertilizer directly into irrigation water at the pivot point. It allows more flexibility in fertilizer timing and costs less than aerial applications traditionally applied to flood-irrigated rice.

“This project may help us improve rice yields with pivot irrigation, and it should also help farmers grow rice in fields that do not have enough clay for flood irrigation or where water’s in short supply,” Stevens said. The progress will be especially important to parts of the world where rice constitutes a staple food.

Disease and weed control present the biggest challenges, according to Stevens. He recommended planting a rice variety resistant to Blast disease. The University of Arkansas recently released Templeton, a variety with improved resistance. For weed control, several herbicide combinations were tested for grass and broadleaf weed control. Stevens warns that pigweed, especially Palmer Amaranth, must be sprayed when they’re small to achieve good control.

Funding for labor and supplies for the research is provided in a grant from the Missouri Department of Natural Resources and an agreement with USDA-ARS. In addition, Valmont Irrigation in Valley, Neb., which manufactures Valley center pivots, contributed the pivot system, along with Mid-Valley Irrigation, a dealer in the Bootheel.

“We have similar experiments going in Brazil, and we’re starting up in other counties,” said Jake LaRue, who manages international projects and products for Valmont. “A lot of things are coming together right now with new seed varieties, chemical applications, sprinkler packages and other technical changes. Within 5 to 10 years we can save a huge amount of water.”

Crystal ball murky for climate in ’09

 Pat Guinan can’t say if you’ll need irrigation or an umbrella this summer and fall.

Guinan, Missouri state climatologist, reports that the Climate Prediction Center’s latest outlook for Missouri forecasts “equal chances of above, below, and near normal temperature and precipitation for both seasons.”

The same holds true for states surrounding Missouri, with one exception: Most Iowans can expect below-normal temperatures.

In May, Guinan adds, river and streamflow levels were running near to above normal across much of the region. Soil moisture levels were also above normal across the northern and central Plains and a large part of the Midwest.

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