Precision field drainage comes of age
Eyeballing it is for the birds. Laser guidance is history.
November 21, 2011 By John Dietz
Eyeballing it is for the birds. Laser guidance is history. Today’s best tool for doing accurate field drainage is a system that uses software, hydraulic machine controls and GPS-guided RTK to slice through potholes and drain fields.
|Robert Deacon uses the AGPS-Ditch Pro system on a large farm in the Red River Valley. The secondary GPS receiver on the scarper improves drainage accuracy. Photos by John Dietz.
East of the Red River near Niverville, Manitoba, Uli Gehrer replaced his laser-guided system in 2006 to cut farmable field drains with one of Canada’s first AGPS-Ditch Pro guidance systems using RTK guidance. Gehrer turned it into a local service, after he ditched his own fields. Five years later, Gehrer says, there were more bids for his drainage service than he could handle. “You get payback fairly quickly. You’re moving half the dirt, you’re spending half the time and it’s far more accurate than anything else,” says Gehrer.
In the Red River Valley, the ditching season for field drainage is the short time between harvest and freeze-up. When conditions are good, farms can put 300 hours into field drainage. It can take up to a week to do a full drainage program on a difficult quarter-section.
|The ISOBUS connector harmonizes the different manufacturer electronics.
Ideally, the shallow-sloping drain will be good for a few years. Eventually, tillage and other field work will interrupt or undo the drain and water will pond again. Then, the crew returns to clean and maybe recut the field drains.
One of the technology leaders for field drainage guidance is AGPS-Ditch Pro. John Deere (Surface Water Pro Plus) and Trimble (Field Level II) also offer field drainage software products using RTK-GPS.
Prior to 2005, first eyeballs and then lasers were used for cutting farmable drains.
“When you changed from eyeballing it to laser, that was fairly substantial. When we changed to Ditch Pro, that change was about tenfold better than the first one,” says Gehrer.
Drainage work turned serious after Manitoba’s 2011 harvest. Manitoba dealer KNR Ag Sales & Service, Brunkild, Manitoba, was swamped with calls and sales. The dealer had sold about four systems in four years; this year, it sold about a dozen in less than two months.
|BOTTOM: RTK-based drainage can build a drainage down to one foot per mile.
AGPS-Ditch Pro is machine-control software for creating or recutting surface ditches. According to the Ohio-based company, Advanced Geo Positioning Systems, this software calculates optimum slopes and grade breaks, and then provides a guided or automated control while cutting.
Grade accuracy is described as equal to one foot per mile, or 0.02 percent. With extra modules, Ditch Pro can be used for laying drainage tile, building municipal ditches and even for final grading on highway construction.
According to Mark Williams, AGPS manager, Ditch Pro was built specifically for the flat Red River Valley areas as a surface-working 3-D version of software already in use for tile drainage. However, it also will work in hilly or pothole areas, he says.
Ditch Pro is more user-friendly today. It can be installed on any tractor. It can work with any RTK-GPS equipment. Software upgrades have been frequent. One recent change enables operators to record the drainage map, reposition the RTK base, and exactly recut the earlier ditches.
The most recent major upgrade, says Williams, puts in a new function. In addition to cutting, it now allows operators to fill and raise low areas with excavated material as an alternative to only cutting and removing material.
“We can fill now to bring up the lowest spot, so the water still drains. Suppose a small pothole is only six inches deep. You may be able to make the ditch through that hole just three inches deep, and take excess dirt from the rest of the ditch to build up the pothole. It’s still drained. Water will run into it, but there would be no standing water in what was the pothole,” says Williams.
RTK has clear advantages. RTK is more accurate on long shallow slopes. RTK operates over a greater distance without resetting. RTK with Ditch Pro could cut ditches that defied the laser system.
With the AGPS software and RTK signals, Gehrer can ditch down from the highest location or up from the lowest discharge point. He can also zigzag and curve to connect low spots rather than draining each low location to a ditch.
“It can figure out the elevation of 10 low spots you want to connect,” Gehrer says. “It will make your minimum slope from hole to hole, not just one straight line from beginning to end. In the end, you move about half the dirt you would with a laser.”
“The machine control has become much smaller, less cumbersome and easier to install in the last couple years,” says Robin Karlowsky, KNR Ag Sales owner-manager. Retail cost for the basic package – a field computer, software and hydraulic blade control – now is approximately $10,000 to $12,000. An annual software insurance package is recommended.
Karlowsky says, “Suddenly, people see other choices than eyeballs and lasers, and they want to look at them. They’re realizing they can be more efficient and save money with the new tools for doing drainage. Years ago, it took a while for GPS to start; once it did, it was a landslide.”