Key points

• Balanced nutrition is key for corn’s rapid growth phase from V7 to VT.
• Soil tests, tissue sampling and Field GX family distinctions help guide input plans.
• Micronutrients play an important role.

Like a child going through a growth spurt, a corn plant requires a lot of nutrition during its rapid growth phase. In fact, a plant can take up 50% to 60% of its nitrogen needs during that V7 to tasseling stretch, says AgriGold Agronomist Sam McCord.

A lot happens during the growth phase. Corn plants are adding many leaves and lengthening internodes within the stalk, root systems are going gangbusters and the plant is determining how many kernels it’ll have down each row. Adequate and balanced nutrition is especially critical during this period of rapid growth.

Level-set before the season begins

Setting yourself up for success through the rapid growth time frame starts before seed goes in the ground. “Start with a soil test,” McCord recommends. “That gives a baseline on what’s available in the soil that you can build on through the season.”

It’s also important to set an attainable yield goal. “If you have an idea of where you want to be, it can help you determine the amount of nutrients you need to apply to reach that goal,” McCord says. “Understanding what your ground can produce, what nutrients you have to begin with, and what you need to add to hit that target will help you reach that goal.”

Position crops to overcome weather challenges

Ideally, temperatures during the rapid growth period will be around 86 F during the day to encourage rapid growth and cool off to the 60s overnight, giving it a chance to reset, McCord says. That, plus adequate moisture, will help the crop thrive.

Obviously, you can’t control the weather. But a good fertility program can help compensate for stressful conditions — such as if drought moves in.

“A plant takes up nutrients with water. If it’s lacking a certain nutrient, it will pull in a lot of water as it tries to find more of that nutrient,” McCord explains. “If soils have balanced and abundant fertility for the plant to take up, it will use water a lot more efficiently.”

McCord typically recommends applying half to two-thirds of intended fertility ahead of or shortly after planting. “That gives you a window to come back and sidedress or make a post-application later in the season,” he says. “It also gives you the flexibility to adjust your nutrient applications if detrimental weather hurts your stand and lowers your yield goals.”

Macros and micros of note

Corn plants take up an abundance of nitrogen, phosphorus and potassium during the rapid growth phase, McCord says, adding that sulfur and zinc also play important roles.

“You want to be as efficient as possible with each nitrogen application. Whenever a nitrogen application occurs, I like to see sulfur go on with it,” McCord says. Sulfur improves nitrogen utilization and nitrogen stabilization, which ultimately helps yields. 

Another important micronutrient when it comes to nitrogen utilization is molybdenum. He explains, “You don’t need a big amount, but if you can apply it with your nitrogen, you should. It can improve efficiency and uptake.”

Are nutrients accessible to your corn crop?

Farmers also need to think through the nutrient balance. “Balance is one of the most challenging things to understand and apply,” McCord says, noting there are some that interact and others that do not work well together.

“A soil test can give you a gauge on what’s in the soil, but knowing whether they are available to the crop when it needs it is another story,” he says. An AgriGold agronomist can help you understand your soil test results and put them to use.

Tissue sampling can show whether nutrients are making their way into the plant, McCord continues, noting it gives a snapshot in time of what’s happening nutritionally within the plant. If farmers wait for visual evidence of a deficiency in the field to take action, they’ve likely already lost yield potential.

Fertility needs vary by Field GX^™ family

McCord recommends farmers pay attention to the Field GX^™ families their hybrids belong to. “Hybrid families play a role in terms of when and what amount of nutrients they need for optimal performance,” he explains.

“Field GX Family F, for example, will benefit from later nitrogen applications that will help it flex in kernel depth,” McCord explains. “Family B or Family A hybrids flex in length or girth, which means they require more nutrients earlier in the season.”

His final piece of advice is to follow the four Rs of nutrient management — right source, right rate, right place and right time. McCord says, “Getting those nutrients closer to the plant when it needs it will help you get the most bang for your buck on nutrients.”