Farm Progress

Strategies for managing consumption and use at the farm include value propositions to mitigate undesirable evapotranspiration and ensuring the most value from the water consumed.

March 2, 2017

4 Min Read
WEIGH THE OPTIONS: When managing water use and consumption at the small watershed and farm level, producers should consider the relative value or cost of water and the effect on yield.

Editor’s note: This article is the latest in a series of articles discussing water consumption and use from a supply perspective and as it relates to watershed management concepts. This series will be produced in connection with the Nebraska Water Balance Alliance (NEWBA) and several of its associates.

There's an old saying that goes, "No single raindrop wants to believe it is to blame for the flood." When we talk about management to scale at the watershed level, it could be easy to dismiss the individual farm or watershed from responsibility in balancing a water budget at the larger scale. As we've discussed in recent articles, using a least-common-denominator approach could help meet the needs of the larger watershed, while allowing a localized approach at the smaller watershed and individual farm level.

The idea is to manage to a uniform goal and adopt your management strategies for your specific situation to reach that goal. In this case, the goal is to optimize water management to balance the water budget. "We can all have the same destination, but take different routes to get there," says Frank Kwapnioski of H2Options Engineering LLC of Lincoln and NEWBA adviser.

When managing water use and consumption at the small watershed and farm level, producers should consider the relative value or cost of water and the effect on yield. So, there may be some tradeoffs to consider. "What are the higher values from competing forms of consumption and use? As management takes shape or moves forward, some baseline or mechanism to measure against is needed," Kwapnioski says. "I believe the value proposition isn't just a direct one-to-one relationship; it's management of total water consumption to produce higher-valued outcomes, however they may be defined."

Value propositions
One specific example in dryland agriculture on the High Plains is residue management. Merle Vigil, research soil scientist at USDA's Agricultural Research Service in Akron, Colo., notes taller wheat stubble helps mitigate evaporative losses in several ways. Stubble helps mitigate evaporative losses by reflecting light and heat, protecting moisture from wind, trapping snow, minimizing the impact of rainfall on bare soil and improving infiltration.

"All of that ultimately impacts water storage. And you should be able to measure the increase in yields with increased soil water storage," says Vigil, adding that with 18 inches of stubble height compared to 10 inches, "We've seen anywhere from 1 to 3 inches more water in the soil. Some years it's as high as 3. But even if it's just an inch of more water storage, when you look at a water storage production function, 1 inch of water is worth 6 to 7 bushels of wheat. It can be as much as 15 bushels of corn depending on the rotation, 160 pounds of sunflowers and about 240 pounds of proso millet."

Cover crops are another value propositions, adds Ted Tietjen, NEWBA project coordinator who farms near Grant. This means considering not only what you're losing in increased evapotranspiration, but also what you may be gaining in improved organic matter, infiltration, water holding capacity and weed suppression.

"Right now one of the cover crops used is yellow field peas. It takes an extra 2 to 3 inches of water to plant field peas vs. chem fallow. Those 3 inches are worth about 24 bushels of wheat," Tietjen says. "If you get precipitation during the year to offset that, you're OK. Otherwise, you have a lag effect, because you have negative effect on the wheat crop behind it."

It's also worth considering specific crops or hybrids to plant based on consumptive use, notes Tietjen. There's a big difference in the amount of water used in 114-day corn compared to 97-day corn. "For every four days you add to the growing season for the crop, you also add an inch of water," Tietjen says.

"In rain-fed corn in the western half of Nebraska, you normally get enough to get to tassel. If you run out at that point, it's all downhill," Tietjen adds. "In July, if you have 4 inches left on your allocation, you look at growing degree days, and you can project how much water it's going to take to reach maturity. If you have rain, you can subtract the amount of rainfall you receive."

In water-short areas, where water consumption currently exceeds available water supplies, it may be necessary to consider changing from current cropping patterns to a less-consumptive cropping rotation. Although it isn't always an easy conversion, it could be necessary and supported by focused efforts to identify, develop and expand potential alternative markets.

Driving adoption
Whatever the value proposition is, it starts with measuring and learning, making use of tools like weather stations, soil moisture probes, flowmeters and atmometers to know how much water you have available and how much you're using. "If you don't measure what you don't know, how are you going to make a better decision?" asks Roric Paulman, NEWBA member who farms near Sutherland.

The challenge is the adoption curve associated with using the right technology to base management decisions on. "In the absence of doing something, you get no output," Paulman adds. "What's the technology at the entry level? If you do this entry level, what's the next step? How do you step into that space in a leadership role and engage the next layers?"

In upcoming articles, read about additional value propositions in larger watersheds and municipalities.

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