What are playas and what can they do for Kansas farmers? New study hopes to find out

This summer, Kansas researchers will join an international team to conduct a study looking at the interaction between playas and agriculture in western Kansas.

The results of the study will help farmers decide whether to farm through or around playas, small temporary wetlands, on their property.

“The goal of the study as I see it is just kind of understanding whether it is in the farmer’s benefit to go ahead and farm right through playas, or whether it’s in their long term benefit to protect them,” Mark Bowen, an assistant professor of geography at Minnesota State University Mankato who is involved in the study, said.

In addition, the results of the study will inform conservationists and policymakers how best to conserve playas.

“It’ll really help our efforts to do playa restoration and much more,” said Matt Smith, the conservation delivery manager for Playa Lakes Joint Venture, a regional partnership dedicated to preserving playas, prairies and landscapes of the western Great Plains.

“It’s going to help us understand more about the recharge aspect of playas as well,” he said. “It’s not whether or not they do recharge. We know they do. But having a fuller understanding of the amount of that recharge will be very important as well, and this is one of the first studies in Kansas to look at that.”

The study will be conducted by a team of researchers from the Kansas Geological Survey, the University of Waterloo, the Kansas Biological Survey, and Minnesota State University-Mankato in Groundwater Management District 1 in western Kansas.

What are playas and why do they matter?

Playas are small, shallow, intermittent wetlands that are disconnected from more permanent sources of water like rivers, streams and lakes. As a result, they only fill with water as a result of rain, snow or runoff from the nearby land. Playas can remain filled with water from a month to a whole season.

But while playas may be small, the nearly 22,000 in Kansas play a critical role in replenishing the waters of the High Plains Aquifer. Previous studies have estimated that playas recharge aquifers at nearly 10 times the area that surrounding land such as grasslands and prairies do. In addition, it is estimated that 95% of the water replenishing aquifers comes from playas.

So what gives playas this special trait?

Randy Stotler, a lead scientist on the project and an associate professor at the University of Waterloo and adjunct professor at the University of Kansas, explained that playas’ ability to recharge the aquifer comes from their soil composition.

He said that during dry periods, the clay bottoms of playas dry out and crack. When it rains, the water is able to seep down into the cracks and get deep into the soil. Eventually, the clay will absorb water and swell up, sealing the basin and holding a lot of water, forming a small lake.

“[They act] something like a water tower,” Stotler said. “There’s this reservoir of water and it’s able to seep down into the subsurface.”

Stotler estimates a larger playa may be able to replenish 3-4 inches of water a year. For a 4-acre playa, that would be enough water to support a few households for a year.

“The amount of recharge through playas will not make up for the amount withdrawn through irrigation,” Smith said. “But we do say that the amount of recharge can provide a sustainable amount of water for towns and for individual farms.”

In Groundwater Management District 1 where the study is taking place, water levels have declined nearly 11 feet in the past 25 years, according to a Kansas Geological Survey monitoring project.

What do playas have to do with farming?

Playas are often small and given that playas are often dry and relatively small, farmers might plant crops in them, hoping that the playa doesn’t flood that year.

“If you’re a farmer that happens to have three or four playas in their field, I can see how it would be a real burden to try and avoid these things,” Bowen said. “But I’ve also been out there enough when these things are storing water...the crops are either flooded out or you know they’re just not going to make it because of inadequate soil.”

In addition, planting over playas or plowing near them could result in soil piling up in the playa, possibly reducing their ability to recharge the aquifer. This study hopes to determine whether that is true or not.

“Our hypothesis is that in general, fields that are farmed have a lot more sediments that come in from the surrounding area that fills the cracks and so we don’t have the really good fast recharge pathways,” Stotler said. “[It’s] just a hypothesis, so it’s something that we’re testing and could be proven wrong.”

After wheat harvests are complete this year, Bowen will travel to western Kansas to collect soil samples, which will allow him to see how agriculture may change the rate of sediment accumulation and what impact the soil has on playas’ ability to store water.

More broadly, the study hopes to see whether planting in playas or conserving them results in a better economic outcome for the farmer long-term. As most of the playas in Kansas are on private lands, any conservation effort will require the landowner’s consent and providing a clear benefit for conservation might help.

“If more often than not, you’re coming out on the positive, conservation isn’t a winning argument, but if more often than not you’re coming out on the losing end of this bargain, you’d be much better off, you could actually maybe even get some economic benefit of enrolling it in a conservation program,” Bowen said.

If the study does find that conserving playas are in farmer’s interest, the study might also answer which playas should be of interest.

“What’s better to protect, several little [playas] in a field or one really big one? And that’s one we don’t know the answer to, so that’s kind of what the purpose of this study is,” Bowen said.

What’s next?

The researchers expect to have preliminary results next spring with the full results of the study coming by the end of next year.

For farmers interested in conserving playas on their land regardless of the outcomes of the study, Smith said that the U.S. Department of Agriculture and state agencies such as the Kansas Department of Agriculture have programs that provide assistance and funding for playa conservation.

For people who want to learn more about playas, he recommended visiting the playas on public lands managed by the Kansas Department of Wildlife and Parks near Dodge City.

Regardless of the outcome, the researchers hope that the study will bring about increased exposure to playas and their benefits.

“Playas are a really important resource for the state, and there’s a lot of potential there for conservation, and not only just protecting the environment, but also playas have a really good potential to sustain irrigation and agriculture on the High Plains,” Bowen said. “They’re certainly an underlooked resource and certainly an undervalued resource.”