Maximizing the Value of Water

By Christine Hunt

"Irrigation contributes billions of dollars a year to Nebraska's economy. And that's just looking at how much grain is produced and sold, and how much diesel fuel and other inputs are used. Irrigation manufacturing provides additional benefits to the state. If you look at the multipliers of how that works through local communities, it adds to the value of irrigation. I think many of our rural communities realize that irrigated agriculture is important to their sustainability," said Derrel Martin, professor of irrigation and water resource engineering in the Department of Biological Systems Engineering at the University of Nebraska-Lincoln. "I think people across the state are interested in how we utilize and value our water resource," he said.

Nebraska's Water Resources
"There is a finite supply of water," said Martin. "In Nebraska, the state receive, on average, about 22 and a half inches of precipitation a year. That's the average across the state. That's our main source of water year in and year out." Nebraska does have the High Plains (Ogallala) Aquifer that stores a vast volume of water; however, according to Martin, the issues arising today are really related to the flow of water in streams, not the volume of water in the aquifer.

Demands on Nebraska's Water
Groundwater feeds many streams in Nebraska. As groundwater is pumped for irrigation, the water elevation may drop over time and can affect stream flow, said Martin. With more irrigated land than any other state, Nebraska is facing issues with maintaining stream flow; for example, in the Republican and Platte River Basins, said Martin. "That's what's driving a lot of water policy and water management issues at the resource level, not at the farm level necessarily, but at the watershed or Natural Resource District level," he said. "Not just in Nebraska, but all across the western United States."

Almost 94 percent of the land in Nebraska is owned by a private entity, someone trying to make a living, said Martin. "What can be done that enhances their opportunities while not being at odds with managing the watershed. I think that's where we've evolved to today, " said Martin. "We're taking a bigger, more holistic picture of looking at the water resources that we have and trying to ascertain where the water goes and where it come from. In the end we have to decide how much water is available to use and how to manage the water. How can Nebraska's water use be sustainable?"

Managing Water While Protecting the Watershed
UNL's Department of Biological Systems Engineering, along with graduate students and extension educators, form a team that takes a dual view of managing water, said Martin. The team looks at water management at the farm level so farmers can be profitable and efficient, but also studies how that water use impacts the watershed, he said.

There are times it might be best for the farmer to be as efficient as possible and use every drop of pumped water for crop use, said Martin, "That doesn't necessarily enhance the watershed. You have to look at where the water goes that we pump from groundwater or that we divert from streams. When you pump water from groundwater and it goes to your center pivot, how much of that water might evaporate into the air? How does water evaporate off the canopy. When you use surface irrigation, does the water soak into the soil or run off the field?" he said.

Through years of research and the use of computer modeling and simulation programs, Martin and his colleagues answer these questions, as well as many others. Research enables the team to make predictions and look at how management strategies or new designs might affect water balances, Martin said.

The Water Optimizer -- Value from Each Drop
Martin and the team, along with UNL Professor of Agricultural Economics Ray Supalla, created the Water Optimizer though 25 years of research. The Water Optimizer is a computer program developed to help producers and water policy analysts maximize the value from the limited water available for irrigation, said Martin.

A significant portion of Western Nebraska is affected by water allocation programs, which means a producer is given a set volume of water to use, either annually or on a multiyear basis, he said. As a result, producers must look at which strategies to use in terms of what crops to plant and how much water to allocate to each crop. Decisions become more complex when producers have more than one irrigated field if they are able to move water back and forth between those fields, he said.

The Water Optimizer program allows producers to enter the raw production costs, commodity values and their own production goals. The program then determines the alternatives that produce the maximum net return for the producers. Martin went on to explain if an agricultural producer wants to use half of the field for corn or soybeans in a rotation, the program is designed to allow for that.

Growth in Technology
Technology is rapidly becoming available to producers that will allow them to better monitor soil and crop conditions in the field, "I think we are really on the cusp of that," said Martin. As farms increase in size, producers don't have time to find the sensor in the field and read it by hand, he explained. Today, equipment installed in the field can send messages by satellite or wireless networks to a producer's computer or phone. Cell phones can also be used to remotely turn a center pivot on and off, monitor what the pivot is doing and even get warning signals if a pivot has a problem, he said.

Today they're developing irrigation systems that allow the producer to divide the center pivot field into different sectors, said Martin, applying a different amount of water to each sector. It's another way producers can get more value out of their water, he added.

Martin believes the use of electronic technology in farm fields will be more common in the next decade. The researchers' challenge is to make the technology effective and reliable, as well as measure and monitor conditions at a cost that is reasonable to producers, he said.

Making Research Relevant
Sometimes in research settings, we're reluctant to step forward until we think we know everything about the problem, said Martin, comparing research to peeling back the layers of an onion. "Every time one layer is peeled back, there's another layer. You're smarter. You learned something, but you are not done" he said.

"We're often not willing to say that we already know a lot. We need to get reliable information utilized now rather than waiting until we've got all the way to the core of the onion," said Martin. The public can't wait until we get to the core. We'll never be there."

"I think we need to make sure that what we do is relevant to stakeholders and not just those in Nebraska but across the Great Plains Region," said Martin. "We try to ensure that what we do matters to people."

The Need for Sociological Research
Research is needed to find out what matters to producers and communities, Martin said- not just the hard sciences, but also the social sciences. We need to learn how producers think, what kind of information delivery they want, who they trust. "I think we need to do more, to really understand our stakeholders and clients," he added.

Past research shows that when people are not limited to how much water they can pump and they all raise the same crop in the same county, there will be a wide range in the amount of water applied, said Martin. It's the same weather, the same crop, the same county, the same soil, but there is a huge variation in how much water people apply, he said. Researchers are interested in the reasons for that, what tools producers are using for their decision making and what barriers they wish to avoid. "I think we need to do more to understand these issues," he said.