Chemigation—sometimes also known as fertigation—is the use of irrigation systems for the controlled and efficient application of fertilizer, herbicides, and other chemicals to crop fields or pasture. By using chemigation methods, farmers can both save money and avoid applying excess chemicals, which can leach into the soil. In this interview, Bob Gills, the director of global sales for Agri-Inject, the leading player in the chemigation market, speaks with Kris Polly, the editor-in-chief of Irrigation Leader, about the benefits of chemigation and why the method is well suited to markets like New Zealand, where it is not yet widespread.

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Kris Polly: Please tell us about your company, Agri-Inject.

Bob Gills: Agri-Inject is the worldwide leader of chemical injection systems for the agricultural market. A large portion of our business is in center-pivot irrigation, but we’re also used in subsurface drip and in greenhouses. And we’re not limited to just agriculture. We are also very popular in golf and athletic field chemical injection.

Kris Polly: So your technology allows fertilizers and herbicides to be added directly into the irrigation water of irrigation systems.

Bob Gills: Yes. You often hear the term fertigation, which refers to injecting liquid fertilizer through an irrigation system. But the more encompassing term is chemigation, which refers to the accurate and timely injection of fertilizer, herbicides, insecticides, and fungicides through an irrigation system. The terms are often used interchangeably.

Chemigation—and fertigation specifically—has been around for a while, and we’ve been in business since 1983, designing, selling, and supporting our fertilizer-injection systems. The market has been growing over time. Farmers are educating themselves on how and when a plant uses fertilizer, and they better understand how to apply fertilizer to minimize plant stress and maximize yield. The more farmers realize how an injection system can improve the overall management of their farm, the more attracted they are to our technology. We strive to be the fertigation thought leader; our solutions are now an integral part of the precision agriculture market.

Kris Polly: Recently you participated in a tour with a group of New Zealanders. Can you tell us about your role in that tour and your time with the participants?

Bob Gills: Earlier this year, I was in New Zealand for business, and while I was visiting a dealer that we’d signed up at the end of 2017, he mentioned an upcoming fertigation master class put together by IrrigationNZ. I decided to attend. That gave me the opportunity to meet Andrew Curtis and Steve Breneger from IrrigationNZ.

I was asked to make a presentation on fertigation and our practices in the United States. In my presentation, I discussed the value of fertigation from both a business and an environmental point of view. That caught the ears of a number of farmers and dealers, including Pāmu Farms, the largest state-owned farm in New Zealand. The whole thing developed from there, and it eventually led to my working on an itinerary for a U.S. visit by three New Zealanders, with it all culminating in a visit to Husker Harvest Days. Simultaneously, Andrew coordinated a tour with a much larger group, and we were able to get a combined group of 30 New Zealanders to converge at Agri-Inject headquarters in Yuma, Colorado, where they all spent the day learning about the tools we provide for chemigation and fertigation in the United States and the world and the value derived from reducing input costs, improving crop yield, and addressing environmental concerns.

Kris Polly: Based on your experience, what are some of the differences between New Zealand and the United States as far as the use of chemigation?

Bob Gills: Chemigation isn’t used very much in New Zealand. In fact, I spoke to one farmer who, when he had to apply chemicals late in season, hired a helicopter to drop chemicals over 60 irrigated acres. For the cost of one application, he could have paid for a system using known and proven chemigation methods. The other thing we discovered was that in New Zealand, center pivots are quite commonly used for dairy pasture irrigation, but granular fertilizer is applied using traditional methods. This is not very efficient, and it creates environmental issues. There is a need to measure and control the amount of fertilizer applied to the pastures. When too much is used, excess nitrogen is taken up and stored in the grass and consumed by the cows. The cows then release these nitrates back into the ground through urination, adding nitrates to the groundwater. To address this problem, we’re helping them with the just-in-time delivery of fertilizer. The objective of fertigation is to give the plant what it needs when it needs it—no more, no less. Our fertigation technology, in this case coupled with the center-pivot irrigation system, is the type of precision agriculture that today’s farmers need. It’s an all-around win for everyone involved, reducing input costs through the more–efficient use of nitrogen, improving crop yields, and reducing the contamination of groundwater by waste.

Kris Polly: It sounds like the New Zealanders were interested in what you had to show them in the United States.

Bob Gills: They were, and that’s why they were so interested in spending the day with us in Yuma. We’re beginning to develop some great relationships with farmers, dealers, IrrigationNZ, and the New Zealand irrigation schemes. The beauty of it is that fertigation affects two very important areas. First, the business: The farmer spends less on crop inputs without sacrificing yield, and in many cases even improving it. Second, the environment: Nitrogen use is much more targeted and controlled. The same environmental issues are found here in the United States—in Nebraska or out on the Delmarva [Delaware, Maryland, Virginia] Peninsula, for example. If the amount of nitrogen put down is more effectively managed, giving the plant what it needs when it needs it, then leaching and evaporation will be minimized, and everybody wins.

Bob Gills is the director of global sales at Agri-Inject. He can be reached at