How do water levels in the soil impact crops?

Minnesota cornWhat if farmers could input their farm data into a computer model that would help them decide whether to invest in drainage systems? Or how much fertilizer (enough, but not too much) to take maximum advantage of current soil moisture conditions?

A four-year research project funded by the Minnesota Corn Research & Promotion Council (MCR&PC) is looking at the interrelationship of drainage, soil type and farmer management decisions to the vigor of crop plants and, most importantly, the amount of grain they yield.

“We’re looking at water that might be stored in the soil profile for the crop,” said University of Minnesota Soil Physicist Jeff Strock. “We’re looking at water that might be evaporated up into the atmosphere, we’re looking at water that might be percolated down to deeper ground water or returning to a river.  We are looking at the water balance from a smaller scale, a field scale, to find ways we can add more water, save more water for the crop during the growing season.”

Strock is leading a team of seven scientists, working at three sites across southern Minnesota and eastern South Dakota, to conduct this farmer-funded research. In Waseca and Milroy, Minn., and Beresford, South Dakota, researchers have placed an array of soil temperature and moisture sensors in various locations of both drained and undrained farm fields. In addition, the team pulls up plants at each site to assess root size. Recording grain yield for the locations helps bring the relationship of all these factors into focus.

Starting in the coming year and for the two following years, they will also gather leaf area index data — how big do the corn plant’s leaves get — as an additional data point.

This research that follows the water trail through the soil could provide proof that drainage systems help alleviate flooding and soil loss. Or show which drainage systems don’t deliver this kind of benefit.

“This could have a very large impact from both economic and environmental stewardship perspectives,” said Strock. “Do we have nutrients flowing down the river, or are they stored in the soil profile for plant use, which is what we and the farmers want to see happen. The goal is to help the farmer keep the water there, and keep the nutrients there where the crop can use them.”

With the observed changes in climate in the upper Midwest — rainier springs followed by drier summers — helping the individual farmer understand how to work with the prevailing soil moisture conditions on his or her own farm becomes more and more critical.

“These three distinct locations have distinct soils that we are working on,” said Strock. “They are representative of the areas. They are present in millions of acres of corn production across the region. We can’t select all the soils present in these areas, but that’s where the modeling comes in. Once we understand the behavior in the six soils we are working with, we can develop the models to understand how water behaves in the other soils.

We’re not only just looking at soil and water, but also how management affects the crop. What makes this project unique is that we are looking at both above ground and below ground characteristics of the plants. What’s the leaf area index? What’s the root geometry?”

Strock was one of dozens of presenters who displayed data and talked about his work with farmers during the MN AG EXPO 2015. EXPO provided an opportunity for Strock and other researchers to show farmers firsthand the methods and goals of their research projects, and detail how corn check-off investments are working for farmers in support of goals like land stewardship and environmental conservation.

Minnesota corn farmers support about $4 million in research projects annually. You can learn more about these efforts in Minnesota Corn’s “Research Summary” and “Research Directory” publications.

To learn more about Strock’s research, check out the below video from MN Ag EXPO 2015.


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