Chippewa County Extension crops and soils agent Jerry Clark and Shawano County Extension agriculture agent Jamie Patton don't have a crystal ball, but they are predicting a bright future for Wisconsin corn yields. Clark and Patton believe that by 2046, Wisconsin may replace Iowa and Illinois as the heart of the Corn Belt.
During the next 30 years, state corn yields, which now average 160 bushels per acre, are expected to climb to an average of 220 bushels per acre. Clark and Patton believe corn yields in Wisconsin may average more than yields in Iowa and Illinois.
"We have some farms in northwestern Wisconsin, as well as many areas across southern Wisconsin, that already are getting yields in that 200- to 220-bushel range," Clark notes.
Clark and Patton believe a combination of factors — including warmer weather, a longer growing season, better corn genetics, and improved farming practices and technology — will boost corn yields across the Badger State.
"We have been increasing corn yields about 2 bushels per year since hybrid corn started in the 1930s," Clark says. "We've been on a steady climb due to breeding, hybrid selection, better equipment and planting techniques, improved pest management, and GMOs. If we stay on that trajectory of increasing yields by 2 bushels per year for the next 30 to 40 years, we are talking about another 60 to 80 bushels per acre."
Clark admits these estimates may be a bit conservative because they don't take into account the impact of warmer temperatures, which are more conducive to higher yields.
"So, that could actually bump up yields 3, maybe 4 bushels per year over the next 30 years," Clark explains. "That would make most of the state Zone 5, which is what northern Illinois and southern Iowa are now. Much of Wisconsin is currently in Zone 3 or 4."
It has been documented that there is more carbon dioxide in the atmosphere now than in the late 1950s, Clark says.
"If there is more CO2 in the atmosphere, plants use more CO2 during photosynthesis, and that could also help yields."
According to the Center for Climatic Research at University of Wisconsin-Madison, part of the Wisconsin Initiative on Climate Change Impacts, by 2050 winters will be warmer in Wisconsin than they are now.
"Summers will be warmer, too," Clark says. "There are going to be more hot summer days. But the biggest change will be warmer winters. There will likely be more precipitation in the winter, but much of that could be in the form of rain instead of snow. They are showing winter temperatures in Wisconsin warming by 6 to 12 degrees by 2055. The average temperature could be 9 degrees warmer throughout the year than it is now. Our average temperature is 47 degrees [F] now, so that would put the average temperature in the mid-50s."
Clark explains the difference between climate and weather this way: "Climate is what you expect, and weather is what you get. On Feb. 27, 2014, in Eau Claire we had a record low of 22 degrees below zero, and on the same date in 2016, we had a record high of 59 degrees. That is an 81-degree temperature change. That's not what you expect, but that's what we got."
In general, Clark says winters will trend warmer over the next 30 to 40 years. "Some years, we may not see that. But overall, we will," he says. "We'll still see some below-zero temperatures, but we have to look at averages, and this is what they are predicting."
Longer growing seasons have already contributed to higher crop yields. Parts of the state are already seeing longer growing seasons than they were a generation ago.
"The Central Sands has seen their growing season lengthen by three weeks since the 1950s," Clark says. "Much of the southern and central parts of the state have a growing season that is two weeks longer than it was in 1990."
The Center for Climatic Research looked at 55 different ecological indicators — such as the date flowers started blooming and the first sighting of robins — between 1935 and 1947, and compared them to the period from 1976 to 1998.
"They looked at those two time periods and found that 37 of those 55 indicators were earlier [during the later period]," Clark says.
The Center for Climate Research has already observed that the frost-free period is between nine days and two weeks longer now than it was 25 years ago.
"This allows us to grow longer-day hybrids, which typically outyield the shorter-day hybrids," Clark notes. "So if we have a two-week longer growing season, then soon we could grow 120-day hybrids in northern Wisconsin. In southern Wisconsin, we could be looking at growing 120- to 130-day hybrids."
There won't be as big of change in the summer as in the winter. But nights in summer will be warmer. Over the 20-year average that was studied, typically four to five nights each summer were above 70 degrees in Madison.
"The prediction is that we could see 18 to 20 nights above 70 degrees in Madison," Clark says. "If we have warmer nights, then plants won't respire [resting period for plants] as much; cooler nights usually relate to better yields. If the nights are hotter, that would diminish yields a bit. But south of here, corn in Iowa and Illinois will likely be impacted even more greatly than Wisconsin's corn."
The Center for Climatic Research is predicting Madison will have between 20 and 25 days above 90 degrees by 2055. "Right now we have about eight days each summer, on average, above 90 degrees in Madison," Clark says.
With the longer growing season, insect and disease pressure will increase because there could be more generations of insects, and the diseases could start earlier and persist throughout the growing season, Clark says. "Also, more insects could overwinter. Annual weeds could be more aggressive with milder winters. And we could see weed species change. Those weeds that northern Illinois and Iowa deal with now could be migrating north to Wisconsin."
Precipitation affected, too
Precipitation is expected to increase by 20% to 25% during the winters.
"The number of extreme rainfall events of 2 or more inches of rain in 24 hours will increase to about five during a 10-year period," Clark says. "I think this is a very conservative estimate. We had three 4-inch rain events in Chippewa County last year, and in September we had 7 inches of rain over two days in parts of the county. Their extreme rain estimate seems low based on the past couple of years, but it should average out over the next 30 to 40 years."
Warmer weather and increased rain will impact fieldwork. According to Clark, Iowa has already been receiving more rain from April through June.
"Over the past 15 years compared to the 15 years before that, Iowa saw a decrease of four workable field days between April and June due to increased rain. If our precipitation goes up, we could lose field days, too. Even though we are going to have a longer growing season, we could have fewer days in the spring to work in the fields," he notes.
Will Wisconsin soils be able to support higher corn yields? An Iowa native, Patton believes Wisconsin soils can support higher corn yields.
"Our soils, particularly in the southern half of the state, are already supporting really high yields," Patton says. "In the north oftentimes, because of recent glacial activity, we have more sands and gravel in the soils. Additionally, our northern Wisconsin soils are mostly forest-derived, which means they typically contain less organic matter than the soils in the southern part of the state.
"That does not mean our northern soils can't produce high yields," he says. "They just require more attention to detail. Farmers in the north need to maintain and build their soil organic matter levels because these organics are important in storing and providing nutrients to plants. Also, soils with more organic matter often hold more plant-available water, making organic-rich soils more resilient during times of water stress. In essence, soil organic matter acts like a sponge, helping us to store water and nutrients, which in turn helps us grow great corn crops.
"My bigger concern with climate change is not being able to support higher yield potentials, but rather as we keep getting more heavy and intense rain events, the fact is that we may suffer significant episodes of soil erosion," Patton says. "We need to be preparing for these soil loss events."
Patton recommends farmers begin monitoring erosion on their fields and consider installing conservation practices, such as grassed waterways, terraces, field buffers and borders where needed on their farms to reduce erosion and to prevent soil sediments from washing into nearby streams, rivers and lakes. "We should also consider doing more strip-cropping, especially on hilly land."
She would also like to see more farmers embracing reduced-tillage or no-till farming methods. "We know the more residue we leave on the field, the lower the soil erosion rates. With improved equipment, hybrids and management techniques, we are finding no-till systems can compete profitability-wise with conventional-tillage systems, even in northern climates. However, if farmers are nervous about switching directly to no-till, they can start with strip till or reduced till," she explains. "Once they get comfortable with those practices and the change in management needs, the next step would be to transition to no-till. "
Patton also recommends farmers plant more cover crops. "Cover crops are currently the new 'in' practice, but they can be an excellent way to reduce erosion during non-cash crop times of the year."
Patton says farmers need to be proactive. "Soils take hundreds to thousands of years to form," she explains. "We can see that our weather patterns are changing. We need to take steps to protect that soil so we can continue to produce food for the next generation and beyond."
Patton is busy getting information out to farmers, other Extension ag agents and agronomists on how to manage soils, pests and production inputs, while utilizing new technologies and new production techniques.
"Agriculture involves lifelong learning," she says. "Things are changing, and we have to keep learning."
Read a related story about the difference between global warming and climate change on the next page.
The changing climate
Jerry Clark, Chippewa County Extension crops and soils agent, says the climate is always changing.
"It doesn't mean that we have to get into a discussion about greenhouse gases. The climate has been changing since the earth began spinning," he explains. "None of us was here when we had glaciers, and that was a natural change. Man may be contributing to climate change, but it has been changing over time anyway."
Many people are confused about global warming, climate change and if they are the same or different. According to Clark, the definition of global warming is "the increase in the average temperature due to increased concentrations of greenhouse gases in the atmosphere."
Clark defines climate change as "changes in climate variables such as precipitation, snow, wind patterns, sea level and extreme events, in addition to temperature changes."
So is global warming the same as climate change?
"Not exactly," Clark explains. "Global warming represents only temperature increase on a global scale, whereas climate change refers to changes in climate variables such as precipitation, snow, wind patterns, sea level, and extreme events, in addition to temperature changes. Also, the term climate change doesn’t only talk about changes on a global scale, but also on a regional scale. Climate change is a more complete term as opposed to global warming, and that is the reason why it is used more often in the scientific community."
Shawano County Extension agriculture agent Jamie Patton says climate change is leading to different weather throughout the country.
"When I talk about climate change, it's not necessarily that it's just getting hotter. It's about extreme events," Patton says. "If you live in Southern California, the last few years have been hot and extremely dry. If you live in Iowa, parts of that state just went through another extreme flood event. Overall we are trending warmer, but three years ago was one of the coldest winters on record. This year we were plenty wet, while in 2012 much of the country was in a drought."
Patton says, "We are lacking consistency in our weather patterns, and that is what I see as the biggest challenge facing agriculture in the future. That unpredictability is going to be problematic as farmers try to manage inputs to optimize profitability and sustainability. We have great hybrids available — hybrids that can grow well in wet conditions, dry conditions, during short seasons and optimal seasons. But we can’t choose the right hybrid, the right nutrient and pest management regime, or the right conservation practice if we’re uncertain about the next weather pattern we are going to face."