Unpredictable weather, disease pressures, and insufficient nutrition can pose significant challenges for growers late in the season, jeopardizing months of hard work and effort. What can growers do to prepare and support their crops through the end of the season?
With expertise provided by Agronomist Elaina Robards.
The Late Season Nutrition Problem
Preparation for a successful harvest begins long before the end of the season and as early as the previous fall’s fertilizer application. Whenever growers apply their fertilizer, the goal is to ensure the crop has access to plenty of nutrition as it grows while minimizing loss. But by the time the crop has moved through most of the vegetative stage and started into the reproductive stage, the plants have taken up most of the nitrogen and phosphorus contained in earlier season fertilizer applications and the rest has leached out of the soil. To reap the benefits of a whole season of hard work, however, growers need to continue providing adequate nutrition through the end of the season.
“Approximately 40% of the nitrogen corn plants take in through the season is needed from tassel on,” explains Elaina Robards, Agronomist with Sound. “Growers really need to make sure their plants are not only getting nitrogen, but also the other nutrients the crop needs to finish the season strong.”
A successful harvest depends on adequate nutrition throughout the entire season.
With peak nutrient demand occurring between V10 and V14, growers need strategies to ensure adequate nutrition through the end of the season, but early season nutrition may have already run its course. Based on the unique characteristics of their soils and fields, Elaina says some growers have success with split-applying nitrogen at key moments during the season.
“Growers can spoon feed nitrogen as they see fit, based on how different fields are performing and what soil types they have,” she says.
Weather and Disease Pressures
Unfavorable and unpredictable weather conditions later in the season can present difficulties for growers and their crops. Drought can have a significant impact on yield, and because most fungicides need rain or irrigation to water them down, some growers may be forced to skip late-season applications.
“Last year, certain parts of Kentucky were extremely dry,” says Elaina, who covers Kentucky and Indiana. “Because of the drought, there was very little disease pressure, so many growers skipped a fungicide application to save money.”
The risks posed by disease pressures vary based on local conditions, but in general, water-stressed crops are more susceptible to insect and disease pathogens. Too much precipitation too late in the season, on the other hand, can impact yield and dry down before harvest.
“Weather is so unpredictable, but growers try to consider what weather patterns have been like in the past to determine what they might be like this year,” says Elaina. Still, unpredictable and unseasonable weather isn’t that unusual, so growers try to prepare their crop as best they can.
“There are so many factors for growers to weigh, including soil type, how each field is managed, and whether or not they front-load nitrogen,” Elaina says. “Growers know their fields and their management, so to support them, you have to understand their needs and what will work best for them.”
Grain fill is a critical time for the crop.
Preparing for End of Season Success
How a grower responds to late season weather can have a big impact on ROI. Faced with a dry end to the season, many growers will weigh the benefits of eliminating passes across the fields against yield impacts and current disease pressures. But when it comes to nutrition, by the time the end of the season actually arrives, Elaina says growers mostly just have to hope their earlier efforts will pay off.
“At some point, depending on your equipment and resources, you have to trust what you’ve already done and acknowledge that it’s out of your control,” she says. Instead, growers should look to the future, since preparation for a successful end of season occurs months or even years ahead of time.
“Grid sampling can help growers know if they have adequate amounts of each micro- and macro-nutrient,” says Elaina. She recommends growers grid sample their fields every few years and use the that knowledge to work to remediate their soils ahead of planting. Still, periodic grid testing isn’t a replacement for in-season scouting. If caught early enough, many nutrient deficiencies can be remediated during the growing season. And, because some nutrients like phosphorus can become tied up in the soil, tissue testing troublesome areas of the field can let growers know if deficiencies are in the soil or if nutrients are simply not plant available.
Late in the season, access to the nutrients and water microbes provide is critical.
For growers who find themselves running out of nitrogen by the end of the season or with fields that are prone to leaching, split applying and side dressing can help provide more consistent nutrition throughout the season. These smaller, more frequent applications can reduce nutrient loss and help respond to the crop’s in-season needs. Even growers with sufficient nitrogen late in the season may want to consider these practices as a way to improve their nutrient use efficiency (NUE) score and their ROI. By providing what the crops need and not more, growers can help reduce input costs and boost soil health.
“Unfortunately, there isn’t always an instant fix,” says Elaina. “Growers prepare to the best of their ability and then observe. If this crop doesn’t have what it needs right now, they will develop a plan to fix it for next year.”
Tapping into the Soil Microbiome
Healthy soils and the microbes that call them home provide a variety of benefits to a grower’s crop throughout the growing season. Soil microbes not only provide in-season access to plant-available forms of key nutrients, they also increase moisture retention, stabilize the soil, and increase roots’ access to nutrients and water. Late in the season, the access to nutrients and water that microbes provide is particularly critical, especially in areas experiencing drought pressure.
One way to support a robust soil system is with SOURCEⓇ, Sound’s microbiome activator. By mimicking the plant-to-microbe signal, SOURCE attracts beneficial soil microbes that can unlock access to phosphorus and nitrogen — up to 25 pounds of each, in fact.
Plants and soil microbes can work together to carry the crop across the finish line.
For Elaina, one big benefit of SOURCE is that it can be incorporated into existing management practices and it doesn’t require any extra passes, and considering how dry much of Kentucky was last year, that’s a big bonus.
“Some products need to be applied either mixed with water or don’t mix with other chemistries,” she says. “But SOURCE gets a free trip across the field — it can be applied as part of a fungicide or herbicide pass. And, as growers prepare for potential drought periods, it can help alleviate some of the stress on crops.”
SOURCE’s wide application window also helps growers tailor application to best meet their needs. As growers approach the end of the growing season, all their hard work throughout the last year is about to pay off. By strengthening the soil-plant connection, SOURCE can help growers finish strong.
“We might talk about specific nutrients, but they all work together to improve the overall health of the crop, whether that’s fighting off diseases, staying green longer, or providing more nutrients to the grain to increase test weight,” says Elaina. “We want to look at the farm holistically.”