Local farmer Brian Velde approached the Minnesota Corn Grower’s Association with an idea. He had come across an innovative underground irrigation system at a trade show, and wanted to try it out. The association gave him a grant to help with the cost of installation. The University of Minnesota is studying its effectiveness on different soil types. His field has a mix of sandy soil, and good heavy soil.

The system works using drip irrigation. It uses tape strips as “pipes” to bring the water to the plants. The strips are plowed 14-16 inches deep, every five feet along the field. The tape is laid in between every other corn row. The corn rows are set up with an RTK (Real Time Kinetics) GPS system to be 15 inches apart, within an inch of accuracy.

One strip feeds two rows of corn through an emitter on each side every 27 inches along the tape. The emitters are set up to be opened with eight pounds of water pressure, and then close when they aren’t letting water out so dirt doesn’t get in. The fact that it’s pressurized allows the strips to go up and over hills, since it’s not relying on gravity. They are also able to mix fertilizer in with the water to get the nitrogen directly to the roots. If a rodent chews a hole in it, he would be able to splice a section together to fix it. The seeds are tilled at a shallower depth, usually six to eight inches, so it doesn’t affect the lines.

Velde got a permit from DNR to pump water from the Yellow Medicine River. He has a sand filtration system and also mixes in the fertilizer as needed. The need for water is assessed by sensors planted in the field. Velde also takes weekly tissue samples from the plants and sends them to a lab that tells him if there are any specific nutrient deficiencies.

The field is set up in six sections. Two can be watered at a time. From the water filter, the water goes to a PVC pipe, which is set up along the length of the field. The tape strips are attached to the PVC pipes and then extend out across the field. There is another PVC pipe at the end to close the system, making sure water spread out to the plants. Velde estimated that up to 30% of water can be lost using center pivot irrigation if the day is hot with low humidity. That is not a factor with underground irrigation. The sandier soil isn’t able to hold as much water, but the heavier soil is easier to saturate and maintain for a while.

Velde planted three 60 foot “test strips,” areas without the irrigation system, and the results are dramatically visible. A huge advantage to this system is it helps “level the playing field” regarding the soil types farmers have. One acre of soil contains about 2 million pounds of dirt six inches deep. So, it’s simply not practical to replace the dirt across 150 acres.

The system also saves the farmer a lot of money on fertilizer. A typical farm will dump all the nitrogen the plants need before planting the seeds. This leads to waste from using more than needed.

One potential downside is that all drainage has to be installed before the irrigation system can be set up. Once the tape is planted every five feet, you can’t cut more drainage.

Nutradrip is the Kansas company that installed the system with Velde. Netafirm is the company that manufactures the equipment. Nutradrip has been in Kansas for 28 years. It’s unknown how long an irrigation system lasts, but Velde likened it to “like putting a plastic bottle in a landfill, it’ll be there a while.”

Underground irrigation has been used extensivly in the south, as well as California, especially areas with high value crops. but Velde is one of the first in Minnesota. The system is expensive to set up, and it’s somewhat unknown in the Midwest. The drip tape so far has lasted decades, so aside from maintenance, most of the cost is just getting it set up once.

The RTK system lets the auto steer drive the exact same path every year, accurate to within an inch. Studying the yield increase will help researchers come up with figures for how long it will take for the irrigation system investment to pay off. Velde mentioend some farms in the south have added 84 bushels per acre. The reason is the crops are getting perfect amounts of nutrients and water much more consistently. This helps reduce the amount of stress the plants experience from the weather.

Corn has the potential to produce 550 bushels per acre but most farmers around here are happy with 200.

Velde is planning to hold a field day on August 22nd from 1-4 p.m. at 2136 530 St. in Wood Lake. Anyone is welcome to come learn how the system works. There will be experts giving the presentations and displaying the equipment, including a session about how to achieve 400 bushel corn with this system.