More than a third of Montana’s water is used for agricultural purposes.
That number could be higher if farmers start using groundwater and other natural resources.
But, a new study published in the journal Science Advances suggests there are ways to reduce water use without harming local ecosystems.
The researchers found that farmers can use water in the form of reclaimed groundwater to grow crops.
They also use it to help the environment by releasing nitrogen and phosphorous into the atmosphere and the soil.
“In the past, when farmers were relying on groundwater, we’ve had a lot of water that was in the soil that was not being used, but we know that groundwater can actually be very good for the environment, too,” said senior author Michael Fazio, a hydrologist at Montana State University in Bozeman.
The new study looked at the amount of water in groundwater in seven different areas of Montana and found that the most water used was from the land’s surface.
That included the water on top of lakes, streams and reservoirs.
“The land surface is one of the most important factors in water use,” Fazios said.
“There’s really no way to avoid it.
It’s very difficult to do.”
In some cases, the water used in the study was not from the surface, but was from groundwater that was pumped from the aquifer below.
“So, you’d be able to reduce the amount you use by a large amount,” Fizio said.
For example, if a farmer uses reclaimed groundwater for irrigation, that water can be used for irrigation on a large surface area.
But if the water is stored in the aquifier, that land surface area is lost and the land water use decreases.
Water use could be reduced by reusing it to water crops and planting other plants on the same land, Fazios said.
That may not sound like much of a big deal, but it’s a big difference from the amount used in past research.
“It was actually quite a big shift,” Fizzio said, noting that it would take 10 times more water to do the same amount of irrigation.
The research team found that if farmers were using reclaimed groundwater at the same rate as they were using land surface water, the amount they would use per acre was still low, about 6.5 gallons per acre.
But, that would decrease to about 1.2 gallons peracre.
“A lot of people think that if you just stop using groundwater, that you would be able and you would not have a problem,” Fonzio said “But if you use groundwater in a very high enough rate, you’re actually going to be able.”
The researchers compared water use per water use area in the Great Basin with other parts of the country, and found no evidence that the rate of use was decreasing in other areas of the Great Plains.
The water use study also found that in some places, the rates of water use are increasing.
For instance, a large portion of the study’s land surface used groundwater in areas that had low groundwater levels.
And that land use is increasing.
“If you have a really, really, very low groundwater level in the desert, and you have low water use, you might see some improvements in the land use of the desert,” Fuzio said.
“But if it’s high, it’s going to have a very negative impact on the desert’s biodiversity.”
So, if the amount a farmer was using for irrigation was high, and water usage was increasing, the land surface could become very dry and vulnerable to erosion.
The paper says the best way to reduce soil erosion and water use is to use more water in agriculture and improve soil quality.
The study did not address the impact of drought or water scarcity on water use.