Does your cash crop rely on furrow irrigation? If so, you have likely dealt with the headache of busted poly pipe, and Extension Irrigation Instructor, Mike Hamilton at the University of Arkansas System Division of Agriculture understands the struggle.
“Poly pipe comes out of the box looking for a reason to blow up,” he said.
While some poly tubing problems cannot be avoided, others can be addressed before the pipe is ever rolled. Hamilton spoke with Farm Press to give five tips for setting up furrow irrigated acres to reduce your workload and improve your irrigation efficiency.
“The more water management tactics we apply to our irrigation design, the better we are going to be. We can increase our efficiency again and again with just a few practices.”
1. Use Computerized Hole Selection (CHS) software.
Incorporating CHS software into your furrow irrigated designs is a great way to improve water use efficiency. Hamilton said more than half of the furrow irrigated fields in Arkansas are set up with CHS.
“We started using the PHAUCET program years ago,” Hamilton said. “Then we started using Pipe Planner, and we saw our efficiency increase tremendously.”
PHAUCET was developed by USDA-NRCS engineers in Missouri. The no-cost CHS software requires manual measurements of the field boundaries and length of the furrow, then it determines the best hole size and spacing to achieve even water distribution along the poly tubing run.
Pipe Planner kicks it up a notch with a Google Earth feature that allows field boundaries to be drawn on an interactive map. Developed by Delta Plastics, Pipe Planner is a subscription based CHS program that considers all the variables for the best furrow irrigation design – even for pipe laid at an angle across the furrow.
“It is not going to be perfect, but we aim for 90% uniformity in our irrigation designs. There are a lot of variables, whether it is a wheel middle or soil type. Don’t expect 100% perfection, but I promise you that incorporating Pipe Planner is much more efficient than guessing,” Hamilton said.
2. Measure the elevation of the tubing run.
The elevation from the water source to the end of the tubing run dictates the pressure, and by knowing that elevation you can improve your irrigation design. This is true whether the water is falling downhill at 3 to 5 feet, or it is a precision leveled field with less than a 1-foot fall or rise.
While some rely on traditional surveying equipment mounted to an ATV or UTV, others are flying a drone with RTK capabilities. Both methods are extremely accurate, but Hamilton noted the benefits of using a drone.
“The accuracy of these drones is phenomenal. I can fly a drone 300 feet above the surface, connect it to the RTK network, and get the elevation of a tubing run within a half-inch accuracy,” Hamilton said.
Drone technology provides a detailed elevation map with more reference points, and Hamilton said it is a great option for when a field is too wet to drive a vehicle through. “You cannot fly a drone if there is water standing, but you can fly it when it is muddy and you do not want to risk leaving ruts with a vehicle,” Hamilton explained.
One drawback to using a drone is the soil must be bare to get the truest elevation reading, with no vegetation from cover crops or winter weeds to the cash crop. Hamilton noted that for fields with foliage, it is best to use traditional surveying equipment for the most accurate measurement.
3. Raise elevation buildups higher.
Elevation buildups placed in an irrigation design help to reduce the water pressure in the tubing run from start to finish. Hamilton said historically, many have placed their lay-flat irrigation tubing over barrels or half barrels to create inclines, but farmers are now increasing the elevation of these buildups to save on labor and time.
“I would rather put out five buildups at 2.5 feet as opposed to putting out 25 smaller buildups that are 12 inches each,” Hamilton said.
Farmers are getting creative, whether they are designing their own wooden or metal ramps or using jack stands. Others, Hamilton said, may mound up soil or arrange a full barrel with two half barrels beneath the tubing to create a transition.
See this Farm Press feature about Greene County farmer, Clay Smith and how he elevated the run to improve his irrigation water management.
4. Leave the pipe open at the end.
Hamilton prefers to leave the poly tubing open at the end, as opposed to tying it off with a knot.
“I do not like a knot at the end. If the pressure is too high, the tubing is going to rupture. I would rather the pipe be open, instead of it blowing up,” he said.
If the pipe is leaking water, Hamilton said you can idle down your power unit or raise your elevation buildups to stop the water from flowing out the bottom. “That is much better to me than a blow out, because once poly pipe blows up, you are starting over,” he affirmed.
Furthermore, by leaving the pipe open-ended in a Pipe Planner design, the CHS program will determine the pressure changes along the irrigation run and tell you where and at what incline to place the elevation buildups.
Hamilton said, of all the benefits of leaving the pipe open, “The best thing about having the open end is when you are punching holes. You don’t have to sprint to the end of the tubing!”
5. Remove air pockets from the tubing.
Air pockets that develop in irrigation tubing need to be removed. Hamilton said the trapped air not only restricts the flow of water, but also weakens the pipe, putting you at risk for a blowout.
This takes walking the poly pipe and releasing air pockets with something like the tip of an ink pen or the end of a wire flag. Hamilton said the air bubbles are easy to see and most farmers look for them as they walk the tubing run after punching holes in the pipe for irrigation.
“Whether the tubing is blue or white, you will see a little area at the top that is different colored. You can push on it and move it left and right. Those need to be removed or it will cause the pipe to get brittle in that area,” Hamilton said.
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