Why Even Corn Can Get a Bad Night of Sleep
By Christina Stella , Reporter/Producer Nebraska Public Media
Jan. 20, 2021, 5:45 a.m. ·
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In 2020, a stubborn enemy emerged for corn farmers across the Great Plains: drought. Today, about half of the U.S. is in drought, with large swaths of Nebraska, Iowa, Oklahoma, Kansas, and Illinois impacted.
A little dry or warm weather can be a boon for getting work done on the farm. Brian Fuchs, a climatologist at the National Drought Mitigation Center at the University of Nebraska-Lincoln, says, for example, farmers in many pockets of the region enjoyed a rainless, temperate September, allowing them to finish harvest in record time and get a head start on prepping the farm for winter.
“Most producers would say, hey, if it was a warm January, that's actually going to be good for me because it's less stress on livestock, and I can still continue to do farm work,” Fuchs explained.
Yet these weather patterns create risky tradeoffs, posing another hidden risk for plants — hotter nighttime temperatures. That’s expected to become an increasing problem for corn crops that are just trying to get some sleep.
Timing is key
Corn has evolved to expect hot, sunny days and dark, cool summer nights.
During the daytime, the plant photosynthesizes, eventually turning sunlight, air, and water into corn.
At night, it stops that process and enters a state similar to rest — respiration — releasing carbon through its pores. An exhale at the end of a long day on the farm.
But adverse conditions like drought and heat can confuse the plant’s internal “schedule” and cause it to veer off course. Warm and dry evening conditions can especially pose risks to how efficiently the crop will function the following day.
“When nighttime temperature increases to where they're uncomfortable, one of the first things that start to happen to them is that they start to respire more,” said Walid Sadok, an agronomist at the University of Minnesota.
“One of the consequences of that is, by losing that carbon, they reduce the yield potential, because that's less carbon being invested to build [in the daytime].”
The plant also loses critical supplies of water, leading to poor pollination and dehydration. Sadok says the effects are similar to getting a bad night’s sleep.
“We noticed that the following day that photosynthesis — which is the ability to basically do work, capture that carbon from the atmosphere, use light energy — they are less good at that,” he explained.
The stakes are higher early in the growing season: just a few late spring evenings over 50 degrees can sabotage a farmers’ yield prospects. Fuchs says farmers do their best to plan, but conditions can change in a heartbeat.
“This is the time of year that they're buying their seeds, their inputs … and so they're really reliant on the best knowledge going forward: ‘Hey, is it going to be a drought year in 2021? I should prepare for that,’ on the flip side, ‘Hey, it looks like it's going to be a wetter year,’” he said.
“But it seems like a lot of these have really developed quite rapidly, that it really hampers that decision-making process.”
That’s partly why 2020 proved lucky for Great Plains farmers. Despite severe, widespread drought across the Midwest last summer, most farmers were largely spared from losses because drought spread more aggressively in the middle of the season, instead of the critical first few weeks.
Nebraska harvested a record corn crop, despite the entire state suffering from drought by the end of the summer.
Farmers have never enjoyed the luxury of predictability, and agricultural scientists like Sadok say that becomes truer every day.
Climate change is expected to make drought, heat waves, and warmer nighttime temperatures more common — and in some cases, more influenced by each other — in coming decades.
“There is no doubt that the frequency of those extreme events is on the rise,” Sadok said. “We need to kind of make crops more resilient to stresses like drought, high temperature, high nighttime temperatures fast enough to fulfill the needs of a growing population.”
Sadok learned first-hand how drought can impact society as a child in the north African country of Tunisia. Once a major granary of the Roman empire, wheat has remained the country’s staple crop for thousands of years. But the area is prone to recurrent drought.
“As I was growing up, I witnessed turmoil and social unrest because of a sharp increase in bread prices, because of those droughts … people took to the streets and the government severely cracked down on those protests,” he recalled.
“We had those kinds of issues continuously, every five to eight years … so you grow up realizing how important it is in terms of your day-to-day life.”
He eventually realized how many other parts of the world struggle with cyclic drought, including the Midwest. Now, his search for hardier plants begins in virtual reality with crop modeling. The method uses computer models to test how changing a plant’s genes would impact its field performance.
“We run the simulation hundreds and thousands of times, and we see how many times the model, based on historical weather data, has resulted in yield gains,” he said.
If all goes well, the variety is tested in an environmentally controlled chamber that mimics the conditions of a field. Modeling for climate predictions can feel like playing several simultaneous levels of a video game or a strange, cellular round of whack-a-mole.
“We have high nighttime temperature, high daytime temperature. We have soil moisture deficit. We have air drying … each of these things impact different parts of the plant's life,” Sadok explained.
It takes diligent trial and error to understand why some moves work while others don’t.
“Maybe you work on something to mitigate high nighttime stress, but if you improve [that] stress tolerance, you make the plant more susceptible to drought. There are these kinds of trade-offs.”
That’s because a corn plant has more genes than us — about 12,000 extra. Its genetic code is tightly woven, spanning thousands of years of migration, climate change, and adaptation.
Plus, countless varieties need to be adapted for different environments across the world. A home run breed for Nebraska carries no guarantees in Tunisia. “What we are discovering is that you can improve a variety to be more tolerant in one environment, but it could be really a loser in another,” Sadok said.
There’s much work to be done to create enough varieties for farmers to use globally. But Sadok says real hope is on the horizon, and scientists are making good progress.
“We can navigate our way out of this. We can work incrementally,” he emphasized. “And as with everything complex, there are no miracles, but science, logic and reasonableness can lead us to the solution.”
A Holistic Approach
Yet stronger plants alone will not save farmers. Tala Awada, a plant ecophysiologist at the University of Nebraska-Lincoln, says some impacts of climate change, including overall warmer nights, require a bigger toolkit to manage future risk.
“That's something that we can't really address independently. It has to be holistically, looking at the system as a whole,” she said.
Training farmers to manage their land with more sustainable practices is a key part of the puzzle. A warmer, drier world demands smarter water and fertilizer application.
“Instead of going, let's say with regular pivot irrigation, you can go with variable rate irrigation, you can go with drip irrigation,” she said.
There’s also a growing market for precision agricultural equipment that allows farmers to drive their decisions with real-time data and AI.
“You can go with using sensing technologies — and that's where the science is moved — to drive management practices, such as when you put your nutrients in, when you water ... all of it is technology driven.”
Farm shows floors are increasingly packed with precision technology companies looking to demo, and there’s a general feeling that younger farmers are more eager to invest.
But the cost makes these tools inaccessible to many who are just starting their business or taking the reins of their family’s farm.
“All these technological advancements and innovations are driving many of the solutions, but they have to be two things — affordable and manageable,” Awada emphasized. “Give me three buttons to click … don't give me 50 questions to answer to get to one decision.”
Farming has always been risky, but scientists continue to develop better prediction tools for extreme weather events, including drought. But that will take time, Awada says.
Plus, there are no promises technological advancements will be enough to protect farmers indefinitely. Ultimately, the best defense prevents climate change from escalating, requiring a shared global investment in curbing greenhouse gas emissions.
“Are they willing to invest in it? Are they willing to adopt it? So if you think about it this way, holistically, then you get an answer.”
Editor's note: We corrected a previous version of this story that misidentified Brian Fuchs as affiliated with the U.S. National Drought Center. Our article now reflects that he works at the National Drought Mitigation Center.
Harvest Public Media is a reporting collaboration focused on issues of food, fuel, and field. Harvest covers these agriculture-related topics through an expanding network of reporters and partner stations throughout the Midwest. Follow Christina on Twitter: @c_c_stella
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