The Last Glacial Period, also known as the Ice Age, concluded nearly 12,000 years ago. As Earth thawed from its hundred-thousand year freeze, the scattered glaciations above the American High Plains were ablated and their ice melt gradually percolated through porous rock from modern Nebraska all the way to the Texas Panhandle. Alluvial flow from the Rocky Mountains buried nearly 3 billion acre-feet of freshwater in repose, forming the Ogallala Aquifer.

For millennia, the ice melt that had filled the Ogallala Aquifer remained relatively untouched. The hard limestone caliche that comprised much of its upper layer prevented most rainfall from recharging any potential depletion. As such, the nature of this aquifer, which underlies nearly 80 percent of the High Plains, seemed unknowable.

In 1904, the Supreme Court of Texas, borrowing directly from the Supreme Court of Ohio, affirmed this by declaring, “the existence, origin, movement and course of [the Ogallala Aquifer and other groundwaters in Texas], and the causes which govern and direct their movements, are so secret, occult and concealed that an attempt to administer any set of legal rules in respect to them would be involved in hopeless uncertainty.”

Groundwater management across the Ogallala would be defined by that same concession of opacity for decades to follow. With the advent of center-pivot irrigation in the 1940s, the High Plains exploded in agricultural productivity, drawing generously from this perceived boundless supply of groundwater.

According to a Scientific American essay on the Ogallala, the number of irrigation wells in West Texas alone leapt from just under 1,200 in 1937 to over 66,000 in 1971 and wheat, cotton and corn yields boomed commensurately. Farmland overlaying the Ogallala Aquifer became some of the most prolific in the world, producing over $20 billion worth of agricultural products annually. Not everyone considered this resource inexhaustible, though.

“Water was the first thing I asked about when I started farming in 1974,” recalls Dan Krienke, an Ochiltree County farmer who once served as President of the Texas Grain Sorghum Association and is the current Vice-President of the North Plains Groundwater Conservation District. “The man I was farming for at the time had just installed a new irrigation system, and I asked how he knew he would have sufficient groundwater to run it. He assured me the regional university models estimated plenty of water was available and that I should not care about it.”

Instead, Krienke, and many other professionals across the Sorghum Belt, chose to make a career of caring about it.

Now, nearly a half-century later, policymakers and the general public have begun to raise concerns about the health of the Ogallala Aquifer, as well. Agriculture’s contribution to declining water tables across the High Plains has become a subject of newspaper headlines, social media trends and even Congressional hearings.

“The annual groundwater level monitoring data collected… in the state all point to overall declining water levels within the Ogallala portion of the High Plains Aquifer in Kansas,” confirms Matt Unruh, Assistant Director at the Kansas Water Office.

The 2022 Kansas Water Plan, prepared by Unruh and his colleagues at the Kansas Water Office, paints an even more explicit picture: “Projections in some areas show no more than 20 years of water remaining if pumping continues at current rates. Other areas in west central Kansas have already reached the point of no return where many acres of once irrigated land have now been converted to dryland crops or pastures for cattle grazing.”

A common assertion made about the Ogallala’s depletion is that agricultural irrigation drives 90 percent of the current consumption. While accurate, this suggests that all production agriculture on the High Plains is monolithic in its needs. The truth is that there are meaningful delineations to be made between the specific crops and the practices used to raise them on the farms that overlay the Ogallala.

“We are headed toward eventual depletion of the aquifer,” says Jeff Zortman, a farmer in Fowler, Kansas who currently serves as Treasurer of the United Sorghum Checkoff Program. “We are located in a strong aquifer region. Even so, we are seeing drops in pumping rates. Knowing this, we are researching sorghum’s capability to compete with other irrigated crops such as corn and soybeans. Just having sorghum as a relief valve in a mix with more water-demanding crops is making a difference.”

“Just having sorghum as a relief valve in a mix with more water-demanding crops is making a difference.”

Unlike the early days of irrigation on the High Plains, there is little desire for opacity or uncertainty when it comes to water usage these days. In order to improve stewardship of this depleting natural resource, farmers and policymakers alike will need to better understand how crops like sorghum –The Resource Conserving Crop™–can uniquely contribute to key conservation initiatives.

Efforts to better quantify these crop-specific outcomes are already underway in some areas most acutely experiencing depletion of groundwater. In 2018, Kansas released a report on the trial period of its first Local Enhanced Management Areas (LEMAs), a voluntary conservation program that limited participating farmers in the Sheridan County 6 LEMA in northwest Kansas to, on average, a five year allocation of 55 inches per acre (roughly 20 percent less than historic use).

According to Unruh, operating under that resource constraint led participating farmers to plant “a significant increase in total irrigated sorghum acres of over 300 percent. [They] applied an average of 4.1 inches per acre, or 60.5 percent less groundwater than their counterpart in the control area used… This analysis also revealed increased cash flow for producers that grew irrigated sorghum.” Zortman has seen that same impact on his own operation.

“Sorghum has a God-given ability to efficiently convert water to grain,” he said. “It is logical to use efficient water-to-grain conversion crops when we are dealing with a limited water resource.”

While many sorghum farmers would likely echo this sentiment, Zortman believes that even more data on its water efficiency as it relates to profitability would go a long way in encouraging more sorghum acres along the Ogallala.

Krienke recalls when a proactive approach to better quantifying water use helped farmers preempt potentially overzealous policy changes, as well. Farmers in his North Plains Groundwater Conservation District already implemented consistent water metering when Texas published its first State Water Plan in the 1990s, which included estimations of groundwater use per district and suggested appropriate policy reforms for high consumers. Krienke and company were able to prove, through metering records, they had in fact used 27 percent less water than the state was estimating, which helped them to remain fully autonomous as a groundwater rulemaking entity.

In this sense, greater clarity and transparency are essential to conserving what remains of the Ogallala Aquifer. For tens of thousands of years, water that melted from the Ice Age lay in darkness beneath limestone and sediment across the heart of this country. We have only been able to study our impact on the aquifer for a few decades, less than one-tenth of one percent of the time that water lay untapped. There is much we still don’t know, but some truths have already been revealed by this newly shed light.

“Across my entire career as a farmer and a water planner, I’ve tried to make one thing clear,” Krienke reflects. “There are no silver bullets when it comes to conserving the Ogallala Aquifer. We are managing a declining resource. But there are a handful of silver BBs – crop rotation, residue management, later plantings, and so on – that can add up to a silver bullet. While I’ll never tell a farmer what to plant on their farm, sorghum fits very well into that approach to conservation.”

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This story originally appeared in the Summer 2023 Issue of Sorghum Grower magazine.