Irrigation Leader Magazine: David and John Thom on T-L’s Unique Hydraulic Pivots

T-L was recently featured in Irrigation Leader Magazine

By Kris Polly

Since it was launched as a family business in 1955, Nebraska-based T‑L Irrigation Company has grown into one of the biggest center-pivot irrigation companies in the world. In this interview, David and John Thom, descendants of T‑L Cofounder LeRoy Thom, talk with Irrigation Leader about their company’s proud history of innovation, which includes the breakthrough hydrostatic drive pivot, and how its products continue to make life better for irrigated farmers.

Irrigation Leader: Please tell us about your family’s business, T‑L Irrigation.

David Thom: The company was started in 1955 by my father, LeRoy Thom, and Gilmore Love, whose last initials form the name T‑L. I was 8 months old when they started the company. My father grew up on a farm in Ravenna,
Nebraska, so he lived through the dirty thirties here. He was 10 years old in 1935, and the drought left a real impression on him. He realized how much irrigation could benefit the state of Nebraska. After he graduated with an agricultural engineering degree from the University of Nebraska, he served as a naval aviator in World War II. By the time he finished flight training, the war had come to an end, so he didn’t see combat. After the war, he was a soil conservation agent for a few years in the Scottsbluff, Nebraska, area.

Then, he worked on a ranch in Montana for a while as an irrigation manager. He developed irrigation on that ranch, and then he came back and started T‑L in Hastings, Nebraska. Today, T‑L has around 225–300 employees worldwide, most of them at our Nebraska headquarters. Our products are used in 47 U.S. states and 80 countries. We have 200 dealers in the United States and around 50 international dealers.

Irrigation Leader: What were some of T-L’s first products?

David Thom: Back then, one innovative product that we manufactured and supplied was aluminum irrigation pipe that could be used on ground that wasn’t perfectly level. You moved it around by hand. From there, T‑L developed a tractor tow line. Instead of moving irrigation pipe by hand, you pulled a quarter-mile-long line back and forth across a quarter-section of ground. It could go across rolling ground, sandy ground, and ground that you couldn’t flood irrigate. T‑L also made gated pipe and a tow-line sprinkler. We had the first 10‑inch aluminum tube mill in the state of Nebraska. In those days, irrigation was pretty seasonal, so in the offseason, we also manufactured and sold Habco grain dryers and other things to keep salespeople busy during the winter.

Irrigation Leader: T‑L has come up with some innovative products throughout its history. Would you tell us about some of them?

David Thom: At one time, there were as many as 70 pivot manufacturers. When Valley’s pivot patent ran out in 1969, everybody jumped in. There were all sorts of pivots on the market, from water drives and air drives to oil drives and electric drives. All kinds of approaches were being experimented with. T‑L decided to go with the oil drive, for which we developed a patented guidance valve. That led us to our big breakthrough: the hydrostatic drive pivot. Our center pivots moved around at a constant rate, which allowed them to distribute water more evenly than the stop-start drive types that were out there. Today, continuous movement can be accomplished on some brands of electric drives, too, but it is an expensive added option and does not come standard, as it does for T-L systems.

Irrigation Leader: What are the advantages of continuous movement?

David Thom: The one big advantage is that you see an improved water pattern. The pivot doesn’t stop and water in one place; it is always moving at a continuous rate, no matter what speed you set it at. That’s really important with water, but maybe even more so with fertilizer. Say you’re making a one-pass fertilizer application. An electric pivot on a 60‑second timer starts and stops 2,880 times a day at the end tower alone, which creates a spoking pattern and results in lower production. A hydrostatic drive also gives you a much longer drive train life. If a pivot is going up a steep hill in the mud and it stops and has to get going again, it might spin out, whereas a continuously moving pivot can go right through some spots. With our patented alignment valve, we can also speed up one tower. No other pivot can do that. If one tower starts falling behind, it will automatically speed itself up, which helps it dig itself through a mud hole.

Irrigation Leader: What else should readers know about your hydrostatic system?

David Thom: We differentiate ourselves from other hydraulic drives because we’re hydrostatic, which means that our pivot is continuous movement, variable speed, and variable direction. Other companies have 480‑volt electricity, but ours is the one hydrostatic out there. We chose to go that way because farmers are more comfortable with hydraulic equipment than with electric, and they know how to repair hydraulic equipment.

John Thom: Our linear system was developed for us in 1979. It was designed for greater water coverage on rectangular fields and uses the same continuous movement technology and alignment valve as the center pivot. We have many different ways of guiding it. We have furrow‑guided systems, which have a wheel that runs down a little ditch, and wireguided systems, which use an above-ground cable. In 2014, we developed a GPS-guided system, which has real-time kinematics GPS that gives sub-inch-accurate readings. This technology is just like what is used by the GPS-guided tractor systems a lot of tractors use.

Irrigation Leader: Approximately how many gallons of hydraulic oil are in a system?

David Thom: That’s a good question. In a quarter-mile pivot, there are about 100 gallons of oil. That oil is a lifelong oil. You don’t need to change it. All you need to change is your filter, basically once a year.

Irrigation Leader: How would you compare your pivots to others as far as wind resistance?

David Thom: I’ve been around a lot of tornado damage after the fact, and the T‑L will stand up as well as or better than anybody else’s.

Irrigation Leader: In 2003, you developed a precision mobile drip irrigation system. Would you tell us about that?

David Thom: The precision mobile drip system was a knockoff of the low-energy precision application (LEPA) system that Dr. Bill Lyle developed in Texas in the 1980s. We went down and saw that technology and tried to adapt it to Nebraska, but it just didn’t work for us. Our soils were heavier, and it put too much water on too fast. We had some slope, so we were hydraulically leveling our farms with a LEPA system and it didn’t work for us. I thought that if we could figure out a way to spread the water out with a low-pressure dripper, we could make it work here. That’s where the pressure drip system came from. It took a while to find a drip system manufacturer that made emitters big enough that we could use a shorter hose—say, 10 feet instead of 20. When we finally found that, it worked out quite well. Today, it’s the most efficient sprinkler package on the market. One advantage of a drag-drip system like this is that the water makes direct contact with the soil and spreads out in the shape of a pyramid underneath the surface. You have a dry wheel track with no mud.

Irrigation Leader: Was the emitter that you were referring to developed just for you?

David Thom: No. The first one we used originated in mining applications. Now, we use a pretty standard irrigation emitter. One emitter is placed every 6 inches along the hose. We’ll drag 100 feet of hose on some drops as you get to the end of the pivot. We use a standard hard drip hose.

Irrigation Leader: Do you have any numbers on the expected life of your dragline?

David Thom: You know, we really haven’t seen any wear on the dragline, but it’s not too expensive to replace if you need to. The sprinkler package as a whole doesn’t really cost any more than a true LEPA system. It just spreads some water out wider so that you don’t have runoff problems.

Irrigation Leader: Do you have any problems with rodents chewing on the hoses?

David Thom: That can happen. I’ve seen hoses that have been bitten by raccoons. Repairing that is just a matter of cutting out the damaged segment and putting in a union. However, you don’t have the gopher problems that you have with buried drip lines. Draglines require more management than a regular sprinkler spray head. I have found that growers who have a need for the system really like it, and people who don’t really have a need for won’t mess with it.

Irrigation Leader: Can your pivots be powered by electricity as well as by diesel and propane?

David Thom: Yes. If you’ve got an engine running your well, we’ll belt-drive off it to run a hydraulic pump, and if you’ve got electricity, we run a separate small electric motor to run that hydraulic pump. We also offer a reverse turbine pump if you have excess water pressure, which is common in mountainous areas where there is pressurized water coming in. Basically, it’s a water pump running backward that will then run the hydraulic pump.

Irrigation Leader: What are the estimated additional water savings from your system?

David Thom: That depends on the dewpoints, the humidity in the air, and all kinds of other variables. Across the United States east of Nebraska, you don’t lose a lot of water to evaporation because the dew points are so high and the temperature of the groundwater is 55°. West of Nebraska, evaporation is substantial. The savings depend on the situation, but even if you save 10 percent, that’s huge.

Irrigation Leader: You mentioned that the continuous movement of your system plus the hydraulic nature results in less wear and tear on your overall equipment. How does the
life of your gearboxes differ from other drives?

David Thom: An electric pivot stops and starts every minute—2,880 times a day. We eliminate that, which gives us a longer drive train life. Needless to say, if you don’t maintain your gearbox and make sure it is full of clean grease, you’re still going to have gearbox failures, but if you do, the T‑L will outlive anything out there. Now, we see pivots being installed in desert climates where they run 3,000–5,000 hours a year—that’s where the T‑L will really shine. We’re the only pivot out there that really can stand up to those kinds of hours.

The main things we offer are worm gear drives and planetary gear drives. In the industry, the worm gears are standard. We call the planetary an upgrade.

Irrigation Leader: For those who aren’t mechanically minded, would you explain the difference between a worm gear and a planetary?

David Thom: They’re completely different in gear reduction. The worm gear has a 50:1 gear reduction. The planetary has a 68:1 gear reduction. The planetary system is the more efficient gearbox and potentially has a longer life. The planetary system is on a lot of other equipment—all front-wheel-drive tractors have a planetary-style gear that is similar to what we use with our planetary drive option.

Irrigation Leader: Is there anything you would like to add?

David Thom: Something that is new to the pivot industry is radial tire technology. That helps with wheel tracking. There are areas with heavy soils where pivots run long hours, and they get such deep tracks that they either have to put rocks in the tracks, build up a berm on the tracks, or get rid of their pivots. Low-pressure radial technology really cuts down on your tracks. That allows some farms to use pivots that they otherwise wouldn’t be able to.

Irrigation Leader: Do you have any innovations that you’re developing for the market?

David Thom: Right now, we have developed what we call the Precision Point Touch control panel, which has a full touchscreen display. This control allows the user to set application rates, set degree sectors to control multiple end-gun sprinklers, and tie in other equipment such as chemigation pumps so that they are controlled by our panel.

Now, we’re working to simplify that product by moving all the controls to the end tower; we are calling that our Edge Controller. We want to give the user the ability to not have to purchase a control panel and still have full control of their system with their phone, tablet, or computer instead. We’ve been able to run on mobile since 2012; now, we’re trying to get something that has higher quality and fewer issues. That is something that we’ve developed and tested in the last couple of years.

John Thom: The Edge Controller ties in with telemetry controls from a couple of companies we work with; then, the user can run all controls from their mobile devices.

Irrigation Leader: What should every farmer know about T‑L?

John Thom: Like what we said before, our continuous movement system is like no other. There’s also a safety factor: Lightning doesn’t give us the same problems that it gives electric pivots. Our systems are simple, reliable, and long lived.

Irrigation Leader: What is your message to your state legislature and your congressional delegation?

David Thom: Pivots can do the most with the water you have. Over the last 20 years, there’s been a movement to convert from flood irrigation to pivots. We’ve converted lots and lots of acres away from flood irrigation to pivots.

On our own farms, converting gravity irrigation to pivots reduced pumpage by about 40 percent. We’re pumping a lot less water today than we were 20 or 30 years ago, even though we’re irrigating more acres, and that’s a big benefit to the state of Nebraska. Irrigated acres are what makes this state go, and we want to be as efficient as we can. We like the natural resources district system that Nebraska has; it allows more local control of groundwater pumping. We’ve been in a drought for the last 2 years, and pivots have been the best way for us to manage our water.