Drought Impacts on Overall Plant Health
Disease and nutrient deficiency might be secondary concerns.Watch for These
Strategies for drought management throughout the growing season from Pioneer experts.
Every year corn producers somewhere in the U.S. struggle with drought conditions. The extent of corn yield loss is determined by multiple factors, but the severity and length of drought are most critical.
The U.S. Drought Monitor is an excellent resource to monitor your local conditions and surrounding region. If your area is experiencing D1-D4 conditions, Pioneer experts have gathered some key data to help you stay on top of your agricultural water management this season and next.
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration. Map courtesy of NDMC.
The U.S. Drought Monitor map paints a grim picture across the major crop-growing regions, and as of the first week in July, 67 percent of the U.S. corn crop was experiencing some level of drought. USDA crop predictions of late aren’t stirring great optimism, either.
Nothing’s better than news from the front lines. Observations from five Pioneer field agronomists offer a firsthand look at crop and weather conditions going into July and what we can learn.
John Mick covers a six-county area in the south-central portion of Nebraska in his role as a Pioneer field agronomist. About 60 percent of the farmers he works with have irrigated operations and the remaining 40 percent are dryland or “rain-fed” farmers. Customers operate a mix of small, medium and large farms, with some as large as 10,000 acres to 12,000 acres. Corn and soybeans are the primary crops, but wheat and grain sorghum make up part of the crop mix in dryland areas.
According to the U.S. Drought Monitor, a third to one-half of Mick’s territory is experiencing extreme to exceptional drought.
“This started last summer, so it’s a long-term lingering drought,” Mick says. “A lot of older producers will tell you it’s as dry as they can remember. The soil root zone map from NASA better reflects some of the things we’re dealing with because we’re occasionally dry short-term. Because of our agronomic management practices, such as drought-tolerant hybrids, thinner seeding rates, no-till and other management practices, crops can endure very intense short-term drought if it has some subsoil moisture to draw upon.
“We had low rainfall through last summer, but the crop was able to carry itself from rain event to rain event based on subsoil moisture,” he adds. “The big concern from the start of this year continues to be the lack of subsoil moisture to carry dryland crops through. Common questions I’m getting about some fields are what to expect from corn going through this drought. It should be shoulder high; in some cases, plants may be only a foot or two feet tall.
Periodic, spotty rains are occurring, but the normal rainfall that covers a broad area isn’t happening.
Scott Eversgerd’s territory covers most of southern Illinois. Corn and soybeans evenly split the crop mix, though wheat is grown in the southern part of the state. He says dry weather presents interesting challenges.
“It’s been 10 or 11 years since we’ve had a dry year. Some folks forgot what a dry crop looks like. We’re spending a lot of time re-educating them on the issues and why we’re seeing them. Some younger farmers have never seen a dry year.” Eversgerd says.
Soils in Eversgerd’s territory are highly variable and there’s not much topsoil, most of which is thin and shallow. “In addition to dealing with this variability, the crop has stalled out,” Eversgerd says, “Once it’s not getting water, the first thing that shows in corn is the lack of nutrient uptake. We see the corn rolling in the middle of the day. Soybeans are much slower to nodulate, so they’re not producing their own nitrogen.”
Fewer than five percent of the acres in the territory are irrigated.
“We don’t have a lot of ways to mitigate drought in this area,” Eversgerd says. “Naturally, we can manage the crop and soil well by avoiding compaction, keeping the crop weed-free and following good nutrient practices.
“Most of this area received some much-needed rain from July 30 through July 5th. The early planted corn that was starting to tassel had the greatest risk of yield loss prior to the rain. We’ll evaluate these fields soon to determine how much yield was lost and how the plants are recovering. The soybean crop may have suffered some yield loss, but with continued flowering, a significant portion of any yield lost can be recovered. It will take continued rain to build good yields, but the crop is looking better.”
Optimism is strong. “We’ve had a lack of disease and a mild winter. Plus, we’re cutting a great wheat crop,” Eversgerd says. “In fact, it’s probably the best wheat crop most growers have ever cut. We know our soybean crop is mostly made in the second half of July and August, so we have the opportunity for it to be a decent crop.”
As agronomists evaluating hybrids, Eversgerd says they’re learning which hybrids can handle this situation well and which struggle.
Brad Mason is in his sixth growing season with Pioneer. He works with customers in western Illinois. Like other Field Agronomists featured here, a large part of his job is going on field calls with customers and Pioneer reps identifying issues, scouting problems and helping customers understand what crop conditions are and what’s coming up.
“We’re pretty dry throughout my geography,” Mason says. “This is the second driest year on record. We’re known for having popup storms in April and May. We didn’t get any then nor in June.
“We are fortunate that our dark soils hold water well. Because of this, our crop is holding on better than it should for the high temperatures we’ve experienced across most of our acres. The fringe acres: the timber farms, the lighter soils and the clay soils are struggling now. We usually don’t see this until August.”
The average farm size in Mason’s territory is about 800 acres, with typical variations. Corn and soybeans make up most of the crop rotation.
Mason says most forecasts show the area to be in a short-term drought that’s trending long-term, and through July and August, above-average temperatures and low rainfall are predicted.
“This is concerning knowing our moisture reserves aren’t going to be replaced anytime soon,” Mason says. “It’s fairly common for us to go 10 to 15 days without rain, but once we got to 30 days, concern grew quickly.”
Quickly and proactively addressing this, or any concern, is at the forefront of what a Pioneer Field Agronomist does.
“When it comes to things that are abnormal, whether it was tar spot a couple of years ago or with the floods in 2019 and now a drought situation, educating customers about what we’re doing in the field and minimizing surprises, we can help them understand what the current situation is,” Mason says. “Farming is risky enough. We want to provide some surety when we can.
“We’re getting ready to launch our plant health clinics and share with customers where the plant is, what we think it will look like if conditions stay the same or if we get in a wetter weather pattern. We’ll also discuss what types of fungicides might be needed and when and what the disease outlook is.”
Undoubtedly, the welcome rain that fell around July 4th was a hot topic during these clinics. The rain may have broken the dryness, but it didn’t erase the damage the prolonged dry spell had already done to the crops.
While the agronomists and sales reps try to help customers manage risk as much as possible, Mason notes there are only so many pre-season things to do about drought. They work with Pioneer reps to ensure products are placed properly because a stressful year like this is where the rubber meets the roads on hybrids. If they’re placed in the wrong soils and wrong environments, things may not go well.
Conversely, everyone is set up for the greatest possible success when the right hybrids are planted in the right soils and environments.
Mason cites the Pioneer® brand Optimum® AQUAMax® corn hybrids as products good for drought conditions.
“The way we get this drought tolerance is through our testing facilities in California and Chile where we put these hybrids through tests of true droughts we don’t typically experience in the central U.S. It is nice to have these trait ratings in our toolbox so we can offer the right solutions to challenges.”
Lance Shepherd serves Pioneer reps and customers in his native northeast Indiana where corn, soybeans and wheat are raised. Alfalfa, seed corn and seed soybeans are also grown in the region. Customers run farms of all sizes with the average farm size being 2,000 acres.
“Planting for this area started the week of April 10th and there was some planting progress until the beginning of June,” Shepherd says. “It was a wide planting season and most of our rain came before April or in the latter part of it. We’ve only received about 2.5 inches since May.
“This lack of rain is tapping into our moisture reserves, but it’s not as bad as some areas. We’ve not seen the corn wilt, just slow growth. Root development has been slow, as well. But the crop doesn’t look horrific. It’s just slow and steady. Most nitrogen side dressing took place in June, so the crop is responding to it.”
Shepherd adds that farmers in his region have been pushing for earlier-planted soybeans because they see yield advantages, some to the tune of 3/10/bu/day. There were a lot of beans planted in April and early May.
“Soybeans outplanted the corn progress this year. They were at full bloom the first week of July and the earliest corn will start tasseling the second week of it,” Shepherd says.
A mixture of soil types keeps Shepherd on his toes. From coarse, light-textured soils to heavy clay knobs to loams, his customers experience a range of plant health and growth speed. Plants in loam-type soil can be six inches to a foot higher than those in clay knobs and be at the same growth stage.
There are tools Shepherd uses to help customers plan for drought.
“There is always room for improvement,” he says. “The first thing to do is select the best product for a specific acre and use products with good drought tolerance. If you’re looking at Pioneer product guides, a 9 would equate to AQUAMax. But it doesn’t have to be AQUAMax. We have a lot of 8s, even 7s, to work with. What you want to do on drought-stricken soils is to get a stable, consistent hybrid that will perform well on those acres and have good drought tolerance.“Product choice is first and easy. You have to make sure your potassium soil test levels are adequate,” Shepherd adds. “Plants need potassium to open and close stomas. Consider low-till, no-till and cover cropping. Reducing soil disturbance is key to maintaining soil moisture.”
He emphasizes there is no one-size-fits-all approach to drought management. Worthwhile practices include ensuring there is as much plant-available moisture as possible, eliminating cover crops in a timely manner and testing and using select biological products.
“Remember,” Shepherd says. “It’s not always about the quantity of precipitation as much as it is the timing for producing a good crop.”
Aaron Vammer’s territory includes Colorado and a few Nebraska counties. His region is without drought, though a year ago, it was ravaged by the worst drought he has seen in his career. Even the old-timers in the area don’t remember it ever being that dry.
“We started last year with no soil moisture whatsoever,” Vammer says. “It never improved during the year. We got all the way to harvest with very little rainfall. Then we finally started getting snowfall in late November and December. We ended up with enough over the winter to make us feel pretty good. We stayed covered in snow most of the winter.
“Then, spring hit. April was dry and we all were nervous. In May, 10 inches of rain fell and we kept getting it through June. It’s been a blessing.”
Some areas had too much rain, especially in Vammer’s Nebraska counties. Tons of topsoil were lost and some fields were greatly damaged. Vammer’s dad has a weather station and in 12 years, this is the most rain he’s recorded.
“Last year about this time, we had corn that was getting about knee high and starting to dry out,” Vammer says. “It would fire a bunch of leaves; they’d get scalded and plants would die. But a lot of dryland corn kept hanging on and looked okay, although it never got those in-season rainfalls to help it do anything. If a plant finally put an ear on, it would have 20 to 30 kernels. That’s going to cause volunteer issues for the next season. Some guys tried chopping it, but it was hardly worth the diesel to do it.”
Irrigation water consumption was as high as Vammer has observed. Some Nebraska farmers came to the end of their five-year water allocations, and others had to use banked water they hadn’t used in previous years. Some Colorado pivot owners pumped 25 inches to 30 inches of water last year just to keep the crop going.
Colorado farmers’ wells near I-70 don’t have that kind of volume. So, instead of planting a standard irrigation population in the 30,000 to 34,000 plants-per-acre range, some plant as few as 18,000 plants per acre. Fields may get a pass of water every couple of weeks, but they’re managed as dryland corn.
Our Pioneer team had a few more insights on helping manage drought this season and in the future.
Even irrigated acres are experiencing low subsoil moisture. Many irrigation pumps can only supply up to 0.2” to 0.3” of water a day, yet the crop needs more moisture than irrigation can supply.
“Farmers rely on subsoil moisture as a bank account, of sorts, to meet the difference between what the crop is using and what we can apply during the intense period from around tasseling through milk growth stages,” John Mick says. “This year, we hit that point earlier than normal because we had less subsoil moisture, even under irrigation. Last April, I visited with some growers who irrigate, and they started irrigating sooner to apply more water and build up the subsoil amount. It was successful. We filled back the subsoil profile and got ready for irrigation season.”
For surface water irrigators using water from rivers or streams that often run dry in August, Mick says farmers switched to hybrids with shorter maturity thinking dry riverbeds might come early. They also planted hybrids with increased drought tolerance and, in some cases, reduced plant populations in some fields to help mitigate drought.
This year likely won’t create record yields, but farmers may see gains by using solid hybrid selection strategies, sound management practices and managing moisture as well as possible.
Despite the drought’s toll, Scott Eversgerd says what they observe in a year like this is the accumulation of 10 years’ worth of breeding progress in one fell swoop. Small genetic advancements have been made in hybrids since 2012, the last dry period in the area. Farmers don’t see the one-half to two bushels a year increase. Rather, they’ll experience the yield and plant hardiness all at once.
“In a way, it’s really neat to see what our research program has done because of this cumulative effect since our last dry season,” he says.
This season may be tough for area farmers, but more carry crop insurance today than in 2012. Eversgerd estimates 90 percent to 95 percent of farmers have some form of crop insurance.
“Crop insurance will not make you rich, and it’s probably not going to fully put you into the black, but it’s going to keep you from having to sell your farm,” he adds.
One good thing to come from last year’s drought is the realization of how hybrids have improved. Aaron Vammer said he can’t count the times he heard from customers last year telling him that if they had used hybrids from 10 or 15 years ago, they would have been dead by June. But the newer ones kept hanging on, finally making little ears.
“We have several hybrids with drought-tolerant traits, including our new Optimum AQUAMax hybrids that score a 9,” Vammer says. “There are some that score an 8 and compared to our old-school hybrids, they will rock and roll. This has been encouraging to see.”
Vammer says there was a lot of defensive population planning going into this season. It’s likely hybrids with good flex potential will have been planted on the more drought-prone acres. Growers with moisture monitors are observing moisture levels and timing irrigations appropriately. In the future, farmers will be quick to look at a hybrid’s drought score, blend that with the product history and make planting decisions.
Mick, Eversgerd, Mason, Shepherd and Vammer speak in unison when they attribute the drought tolerance, stability and durability of modern hybrids to the latest plant breeding and testing practices undertaken by researchers and plant breeders at Pioneer facilities worldwide. Customer observations confirm this thinking, as well.
While drought, or any other extreme weather, can cause myriad miseries, Mick says each experience gives us an opportunity to learn.
“We’ve seen things such as planter settings, how deep seeds were or weren’t getting planted that don’t necessarily show up with normal rainfall become significant issues,” he says. “An inch of rain makes everyone a good farmer, but when it doesn’t come, our mistakes show up. The opportunity here is to learn how to improve our management.
“We can hang our heads and feel down because of the drought or roll up our sleeves and try to learn from it and improve for the next one. We can learn more in a drought year by looking at crops and seeing what’s going on than when everything goes well.”
Dr. Stan Ehler, the late Kanas State University agronomist and Mick’s mentor, often said, “Everything speaks to you if you learn how to listen.”
Experiencing prolonged drought in-season? Here’s what to watch for and keep in mind before and after harvest.
“Plants keep from wilting by restricting the size, by regulating, the size of the openings. Just like a garden hose, how pressure builds up when you close off the opening.”
- Matt Montgomery, Pioneer Field Agronomist
“If we can alleviate corn drought stress around the blister stage, that's when we being to see yield shaved off the top. Planting a package of products spreads our risk.”
- Matt Montgomery, Pioneer Field Agronomist
Optimum® AQUAmax® hybrids are highly resilient in challenging conditions and responsive to favorable ones. These hybrids are bred to include key native traits that improve your crop’s root system and silk emergence, among other agronomic characteristics, to manage drought stress.
Optimum® AQUAmax® corn hybrids had an average yield advantage of 6.2 bu/A with a win ratio of 63 percent in on-farm competitive comparisons in water-limited environments in 2018. In favorable conditions, they offered an average yield advantage of 4.7 bu/A with a win ratio of 61 percent in on-farm competitive comparisons in 2018.
Optimum® AQUAmax® hybrids include key native traits designed to help withstand drought stress and protect against yield loss. Our hybrids are locally adapted and equipped with strong agronomics. In addition, they are available in a wide range of maturities and technology packages for insect protection and herbicide tolerance.
Pioneer® brand Optimum® AQUAmax® products were grown in 13, 623 on-farm comparisons across the United States against competitor brand products (+/- 4 CRM) in 2018. Water-limited yield data includes 240 competitive comparisons with a win ratio of 63 percent, and favorable environment includes 13,383 competitive comparisons with a win ratio of 61 percent. Water-limited environments are those in which the water supply/demand ratio during flowering or grain fill was less than 0.66 on a 0-1 scale (1=adequate moisture) using the Pioneer proprietary EnClass® system and in which the yield average of competitor brand hybrids at the location was less than 150 bu/acre. Favorable growing conditions are locations where yield levels were at or above 150 bu/acre on average, regardless of water supply/demand ratio. Precipitation levels are interpolated values based on local weather stations. Product performance in water-limited environments is variable and depends on many factors such as the severity and timing of moisture deficiency, heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. All hybrids may exhibit reduced yield under water and heat stress. Individual results may vary.