Supporting soil fertility and late-season nutrient demands with SOURCE

Growers work all season to secure the pay-off of a good yield and high quality corn crop during harvest, starting with fall fertilizer application and soil preparation. With harvest a long way off, growers need to anticipate and keep up with plants’ changing demands, especially when it comes to providing enough phosphorus and nitrogen to support the crop through the end of the season.

As corn moves from its vegetative growth stage and into its reproductive growth stage, its need for nitrogen and phosphorus continues to increase. Will Llewellyn, Sound’s Senior Sales Agronomist, says the window for peak nutrient demand is around V10 to V14. He explains that early in the season, nutritional uptake increases gradually until it speeds up during peak demand. ​“It accelerates to the point where towards the end of that window, most of the fertilizer that has been applied in the fall and spring has generally run its course,” he says. ​“But that happens at a point in time where the plant is transitioning into a period that’s just as important as early growth: grain fill.”

Grain fill is a critical stage, not only for the plants themselves, but for growers; nutrient deficiency during grain fill could negatively impact both yield and quality and hurt a grower’s bottom line. ​“The plant is still pulling in a lot of nutrients and to ensure the quality of the crop, it needs to be fed through the rest of the season,” says Will.

The amount of those nutrients that corn still needs is significant too. ​“At VT, you still have 30% of your total nitrogen and 50% of your phosphorus needed,” says Erik Wolfe, Senior Product Marketing Manager for Sound. ​“There’s still a lot of demand during this grain-fill time.” 

With early season fertilizer at the end of its useful life and much of the crops’ growth still ahead, growers need ways to bridge the gap between fall and spring fertilizer applications and late season demand. 

“This is where soil health can pay off in a big way,” explains Will. ​“Healthier soils mean healthier, more active microbes that can bring nutrients into the root zone.”

To gain access to nitrogen and phosphorus, plants have evolved special relationships with root-dwelling soil microbes. In exchange for sugars, starches, and amino acids released by the plants’ roots, microbes convert phosphorus in the soil and nitrogen in the air into plant-available forms. Healthy soil microbiomes provide growers with a variety of benefits, including access to additional nutrients and better water retention, but building and maintaining soil fertility is an ongoing, long-term project. And even with healthy soils, Will says, ​“It’s still really important to get those nutrients in. Applying an activator to stimulate soil microbes is a really good solution; there just aren’t many other options.”

Erik agrees that growers’ options for bridging the late-season nutrient gap are limited. At this stage, he says, growers generally have an idea of what their crop needs, whether that’s more nitrogen or phosphorus or both. And while some growers may have pre-bought some nitrogen for in-season application, thus locking in their prices, many will find they didn’t pre-buy enough. 

“Right now, nitrogen is really expensive and can be hard to find,” he says, ​“and late season nitrogen is the most expensive nitrogen you’re going to apply, in any year, even when nitrogen is cheap.”

But while nitrogen prices are high this year, corn prices are also high (thankfully!), which means it’s a good time to take advantage of products that could give growers a few extra bushels.

“It’s advantageous for growers to try and increase yield to capture more benefit from current prices,” says Erik. ​“If they can add five more bushels an acre, that’s significant profit.”

Microbiome activators like Sound’s SOURCE for Corn are a good option for growers looking to stimulate the soil’s native microbes and provide the late-season nutrient boost the crop needs to increase yield and maintain quality. SOURCE can be used to reduce nitrogen or increase yield, improving a growers bottom line. With a wide application window — from V4 to R3 for corn — growers have plenty of opportunity to increase nutrient availability throughout the season. 

“Early application and late application of SOURCE both yield good results,” says Erik. ​“And it can be tank-mixed with a fungicide or herbicide.”

As corn enters the grain-fill stage, all of a grower’s hard work and effort throughout the season is poised to pay off. It’s vital that growers continue to support the crop’s nutritional needs, making sure the crop finishes the season as strong as it started.