Need a yield boost? Consider subsurface irrigation

SLIDESHOW: What an SDI system that delivers a corn yield bump of 45 bushels looks like.

Russel Winter is nearing his 81st birthday but that is not stopping this Montgomery County farmer from trying a new irrigation technique.

Before planting soybeans this year, Winter decided to rip up a 14-acre field and install a subsurface drip irrigation system. "I have been wanting to do something for this field for 10 years when it comes to irrigation," he says. He uses center pivots on other farm fields near Bellflower, Mo., but this field was irregular in shape and slope. "It is hilly, long and narrow," Winter explains. "Above ground irrigation just would not work."

Then he talked with University of Missouri Extension agronomist Rusty Lee. "He told me about this tape thing, and I decided to give it a try," he says.

What is SDI?
Subsurface drip irrigation is a low-pressure irrigation system that uses buried plastic drip tubes or tape to provide water to crops. It has actually been around since the 1960s, but is gaining momentum in dry, hot, windy areas where there is limited water supply.

According to MU agronomist Kelly Nelson, subsurface drip can reduce water use by 25% compared to sprinkler irrigation. Nelson has been researching SDI in Missouri for more than a decade.

He finds farmers with SDI systems are avoiding crop stress by using smaller amounts of water applied more regularly. Instead of imitating a couple inches weekly, SDI allows farmers to add less than an inch more frequently.

SDI is about providing the right amount of water, in the right place at the right time. The result is higher yields.

Proof is in the plots
In the neighboring Warren County, Lee is part of an SDI study using drip irrigation to manage water on no-till test plots rotated in corn and soybeans on his own farm near Truxton, Mo.

The study looks at the impact of SDI on yields when placed at 12 and 16-inch depths. It was replicated four times with a check strip where no drip tape was installed. Corn was planted at higher populations of 38,000 plants per acre.

"Last year was a real good year for growing corn in our area," Lee says. "We made the highest dryland corn yields averaging 200 bushels per acre." Still, he saw greater yield gains ranging from 45 to 60 bushels per acre in those areas with SDI. "Our highest yield of the study was 272, that was in a year when corn was growing about as good as it has ever grown in Truxton," he adds.

It was enough to convince Winter to give SDI a try.

Project design
An SDI system is unique to each farm. "One size, one design, does not fit all," Lee says.

Winter has 14 acres within a SDI system. The black 15 mil drip tape with emitters spacing of 24 inches sits 16 inches below the surface and 60 inches apart. There is a 3-inch PVC pipe that receives water on one end of the field and a 4-inch pipe on the other that feeds the system. It is buried 38 inches deep.

It took roughly 200 manpower hours to install the piping system and make the connections.

An adjacent 8 -acre pond provides the water. A hose extends 30 feet into the pond. A revolving screen constantly moves to keep algae from clogging up the intake hose.

A 30-year-old PTO pump was brought back to life and with the help of a tractor will deliver the water to and through the system. Winter says he will run it 12 hours for a .4 inch application of water.

An SDI system costs roughly $700 per acre to install and about $31 per acre in energy expense if using an electric well pump system. However, Lee finds using a conservative increase in corn of 41 bushels per acre and prices of $3.50 per bushel, results in $158 more per acre for the farmer.

Future of farm
Winter says he will continue adding new farm technologies to the operation. He says SDI makes sense because it increases production and conserves water.

"I am always willing to try something new," he says. "You can't just sit still in agriculture. You will be left behind."

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