Searing sunlight, cracked earth, withered plants, wizened cattle—these are the images of climate change. And in parts of the world, a lack of water is driving farmers out of business and threatening the food supply.

Not here. Minnesota farmers can expect more water. And longer growing seasons. What could be better, right?

But in fact, water—too much at times and too little at others—could soon be a major problem for state producers. U of M researchers are trying to help the agriculture industry adapt to our shifting climate and prepare for more dramatic changes ahead.

“Farmers are very receptive to research,” says Jeff Strock, a researcher at the University’s Southwest Research and Outreach Center near Lamberton, Minnesota. “At the end of the day, I’m not advocating for them to do one thing or another. I’m trying to give them a whole bunch of tools in their toolbox.”

Trends and predictions 

“We’ve gotten warmer and we’ve gotten wetter,” says Kenneth Blumenfeld (B.S. ’01, M.A. ’05, Ph.D. ’08), senior climatologist in the Minnesota State Climate Office and a professor in the College of Food, Agriculture, and Natural Resource Sciences (CFANS). Most of the warming so far has occurred as milder winters and warmer nighttime lows. As a result, the U.S. Department of Agriculture (USDA) plant hardiness zones familiar to all gardeners have crept northward 100 to 250 miles.

And the frost-free growing season is now longer. In the town of Milan in southwest Minnesota, three generations of a single family have kept official weather records since the late 1800s. Says Blumenfeld, “We can see that the average frost-free season has lengthened by two to three weeks.”

But with that warmth has come water. And the timing of rain and snowfall hasn’t always been helpful.

 Rain has come as one deluge after another: the kinds of rains that flood fields and tear gullies through topsoil. Minnesota’s wettest year was 2019. The record for the wettest state weather station on record—Harmony in the southeast—occurred in 2018. In 2007 the town of Hokah, also in the southeast, received more rain in a single storm than had ever been recorded in Minnesota: 15.1 inches. Blumenfeld is betting that at least one of these records will be broken before he retires.

A “tendency in the data” suggests more of the year’s precipitation may come in spring. “When people are out doing that field work, they can’t get a break because it’s raining all the time,” says Blumenfeld. Then, during the critical growing season of June, July, and early August, “the apparent shutting of the spigot,” he adds.

“Unless there is some kind of geological or astronomical cataclysm, we know that those trends are going to continue,” Blumenfeld says. 

The Fourth National Climate Assessment released by the U.S. Global Change Research Program in 2018 agrees. The frost-free season will increase by as much as a month in the Midwest as a whole by late this century. Humidity will increase. The pattern of soggy springs and droughty summers will become more pronounced.

Too much and too little 

 Precipitation moving to extremes means a greater chance both of floods and of drought. That’s the worrisome trend that most concerns John Baker, an adjunct University professor and research leader for the USDA Agricultural Research Service. Several years ago, he and colleagues gathered crop insurance claims: “When we analyzed those more closely, three-quarters were water-related, and the thing that surprised us was that it was pretty much equally divided between losses due to excess water and losses due to drought—often in the same county, in the same year.”

Baker says farmers will increasingly struggle with too much water and too little. The University has experimented with using a low-growing perennial such as clover to hold water and soil, and planting corn and soybeans right into the cover crop. But during drought, the cover crop competes with the main crop for water. Says Baker, “You try to come up with something that’s going to work in the wet years, and it causes you problems in the dry years.”

Baker is now coauthor of the update to the Midwest section of the National Climate Assessment. He says the newest update will confirm much of what was predicted in the previous version: Extremes of wet and dry will make crops more vulnerable to existing stressors such as invasive species, insect pests, and plant diseases.

 According to the 2018 assessment, “Projected changes in precipitation, coupled with rising extreme temperatures before mid-century, will reduce Midwest agricultural productivity to levels of the 1980s, without major technological advances.”

Changing crops 

 As our climate changes, researchers expect crops to move into new areas of the Midwest. “We have certainly seen an expansion of the corn and soybean belt to the northwest—more grown in the Dakotas than previously,” says Baker.

Mostly, farmers are simply trying new crops in existing fields. But in some cases, former grasslands have been plowed up and forests cleared. The change may be due to demand and rising prices, or to climate change. Either way, the effect is the same: loss of natural habitat, increased runoff and erosion, and demand for groundwater if irrigation is employed.

In central and north-central Minnesota, as industrial forest has been sold, potato fields have expanded into the sandy pinelands. In some cases, groundwater appropriation for irrigation has reduced cold water supporting nearby trout streams, such as the Straight River near Park Rapids and Little Rock Creek north of St. Cloud.

That has motivated conservation organizations such as The Nature Conservancy, which is concerned about the quantity and quality of water flowing into the Rum, Pine, and Crow Wing Rivers, which feed the Mississippi and help supply the Twin Cities with drinking water. Recently, The Conservation Fund, an effort founded by the former head of The Nature Conservancy, bought more than 72,000 acres of forestland from the PotlatchDeltic timber corporation and conveyed it to the state, says Rick Biske (B.S. ’01), program director for the Conservancy chapter in Minnesota, and North and South Dakota. 

“I think without this protection it would have been cleared and converted, irrigated on sandy soils,” says Biske. “We’re fortunate in Minnesota to be at the headwaters of America’s river. It’s a national resource, and it’s critically important that we protect it and sustain it in the face of these demands on land-use conversion and climate change.”

Irrigating sand Minnesota irrigates only 4 percent of its farmland, but it uses a lot of groundwater to do it, says Vasudha Sharma, an assistant Extension professor who has studied irrigation water management in the Midwest and Great Plains. And the volume of groundwater use is increasing steadily. [See graph, left.]

In addition to reducing aquifers, irrigation can leach nitrogen fertilizer into groundwater. “That’s the major issue that we are facing here in Minnesota,” Sharma says. “We irrigate sand. And if you irrigate more than the soils can hold, it tends to leach.” 

Sharma is trying to help farmers use less water with better results. One technological fix is using soil moisture sensors at field locations to determine the actual need for irrigation. It’s an efficient way to conserve water, but few farmers are using them. A second strategy is to vary water application by soil type. “There are many different soil types in a single field,” Sharma says. Some, like sand, drain quickly. Others hold water. Not all need to be irrigated at the same rate.

“The next step is to invest or put more effort into developing the best management practices so we irrigate efficiently for profitable crop production and also reduce our environmental impact,” she says.

Another way to conserve water is recycling: capturing and reusing water draining from fields, says Jeff Strock at the U of M's Southwest Research and Outreach Center near Lamberton. 

For 150 years, Minnesota farmers have battled an excess of water on their fields by installing tiling and drainage ditches to remove water quickly. However, that drainage can account for increased storm runoff to nearby streams and excess nitrogen and other water quality problems. 

Drained water is a wasted resource, in Strock’s view. So at Lamberton, Strock and colleagues have built four ponds to collect drainage. “And then we’re reusing that water during the growing season to supplementally irrigate our crops,” he says. “It’s something that people are beginning to get interested in, especially as we’ve seen these repeated patterns of dry summers.”

Drainage water recycling promises several benefits: More production and profit. Lower peak flows running off farm fields into nearby waterways. And less groundwater use.

Another possible response to changes in our weather patterns is to switch crops and farming methods, something the University Research and Outreach Centers in Lamberton, Waseca, and Grand Rapids are exploring with the Minnesota Long-Term Agricultural Research Network (LTARN).

 “At the end of the day, we know that with the climate changing [plant types] are moving north,” says Strock. “Then what are we going to grow?” The network aims to experiment with new varieties and new crops raised with different cropping systems.

And the state of Minnesota is working with the University on its Forever Green Initiative. It’s an attempt to develop profitable conservation crops, such as intermediate wheatgrass, that can fill a number of roles—perennial food crop, forage, soil carbon builder, organic sponge to hold water. Says Strock, “It could have a very big impact on flooding and nutrient loss during other parts of the year because you’ve got more storage capacity in the ground.” (See related story “Clean Water with Kernza”)

High-resolution models 

To help farmers plan for a warmer, wetter future, the University has teamed up with the Minnesota Corn Growers Association. Heidi Roop, director of the University’s  Minnesota Climate Adaptation Partnership, is leading the development of sophisticated new climate models, with resolution down to 3-mile-square cells, to provide projections about changing temperature, soil moisture, precipitation variability, drought exposure, and other climate-related variables out to the end of the century. The models will give farmers and the industry highly localized information about suitable crops, risk, and worthwhile long-term investments.

Says Roop, “We have lots of farmers thinking about what will this mean for access to water, and thinking about how this might inform plans for savings or getting loans to drill new wells, or how you might have a productive and economically viable farm moving forward under climate stress.”

 The future push and pull over water— how to get it, where to send it—may even have an impact on the state’s water law, which, as in many Eastern states, gives wide latitude to riparian owners to use water. (See related story “Who Owns Our Water?”)

“The fact is, [water rights law is] always changing in response to new circumstances and conflicts that arise,” says Minneapolis lawyer Louis Smith, who practices water resource law and teaches a University water law class. Over time, he says, state courts have recognized “the interest of other parties to the natural flow of the stream for public and community purposes.”

 In Minnesota, the Department of Natural Resources permits the large-scale use of surface and groundwater, balancing the needs of agriculture, industry, power generation, transportation, communities, and fish and wildlife to an adequate supply.

So far, says Smith, the state has been both well prepared and ill prepared to contend with competition for water. “We’re well prepared in that the riparian system— there are legal principles that are flexible that will look at balancing competing interests.” But, he says, “we’ve been ill prepared as a matter of our community understanding of the science to recognize the limits of the resource and the need to proactively plan and manage.”

Minnesotans have been spoiled by our apparent abundance of water, believing our only problem was to drain the excess when we had too much.

“I think for many years we thought we’re a water-abundant state, there’s no limit to groundwater, no problem!” says Smith. “What we’re learning is water is not an unlimited resource.”

Sidebar: Irrigation and Agriculture

According to the Minnesota Department of Natural Resources (DNR), Minnesota has over 500,000 irrigated acres of farmland which use about 81.5 billion gallons of water annually. 

As of 2017, Minnesota had more than 68,800 operational farms, generating more than $18 billion in agricultural products. The DNR notes that the “recent upward trend of water use increases the strain on water supplies, threatening the sustained operation of Minnesota farms. As much as 90 percent of this water in Minnesota comes from groundwater. The aquifers where groundwater is extracted usually replenish [more slowly] than the rate at which water is used.” 

That’s why careful irrigation strategies are critical, taking into account soil type, crop type, temperature, and evaporation, as well as sprinkler design, such as precision or micro irrigation. Drip irrigation applies water directly to plant roots to minimize evaporation, and scheduling techniques can prevent salinity buildup in soils. 

The U of M provides extensive information on irrigation strategies. Learn more at extension.umn.edu/soil-and-water/irrigation