How Growers Can Use Crop Inputs to Maximize Product Performance

• Soil texture and organic matter can impact herbicide rate selection.
• Jar tests help ensure products are mixing properly.
• Agitation keeps products from separating in the tank.

Modern ag science continues improving the efficacy of crop inputs. Growers today have more options for plant nutrition, managing pest resistance, controlling weeds and increasing profit potential. But variables still exist that compromise product efficacy. Experts say year-round attention to best practices is the path to optimum performance.

Input Performance is Elemental

There are three elements that affect nutrient and chemical availability to a plant. If the soil solution is on the acidic side — a pH below seven — you have iron and aluminum, which bind nutrients and chemical products to the soil so they're not as available to the plant.

Awareness of soil characteristics is fundamental to crop protection product performance, says Kelly Morgan, Ph.D., professor of soil fertility and water management at the University of Florida’s Southwest Research and Education Center.

“You typically have to put more product on soils with higher organic matter than you would in a sandy soil,” says Morgan, who specializes in soil ecosystems for agriculture. “That’s because the organic matter is going to tie-up some of the chemical you've put out.”

Another factor is the “soil solution,” which impacts plants’ nutrient uptake. “There are three elements that affect nutrient and chemical availability to a plant,” Morgan explains. “If the soil solution is on the acidic side — a pH below seven — you have iron and aluminum, which bind nutrients and chemical products to the soil so they're not as available to the plant.”

And the more acidic the solution is, he says, the tighter it binds. On the other hand, in the alkaline range — above a pH of seven — calcium is the culprit, keeping the crop from taking up the nourishment it needs, as well as the herbicides that would give it a jump on competing weeds.

Morgan recommends growers test the soil for each field annually. In the case of shorter-season crops, the interval should be increased to testing before each planting.

“A lot of growers have gotten away from regular testing. But we're trying to get them to go back to it, because if they just make the same applications they did last year, they may get different results,” Morgan says, noting that applying only what the soil needs is better for the environment and improves a grower’s bottom line.

Leon Hunter, agronomy service manager for Syngenta’s east Heartland region, says in his experience, growers do run soil tests regularly, as part of field planning.

“If a soil analysis indicates there are nutritional differences, be it micronutrients or macronutrients, growers can correct the soil pH,” he says. “Fertility and lime is one way to do that.”

Those corrections have a positive impact on herbicide use, Hunter adds, helping growers increase bushels overall.

Slow and Steady Wins the Race

Some common shortcuts to crop protection plans often adversely impact product performance. Using incompatible products, adding generics to name brands, and not following recommended mixing orders can all lead to problems. In some cases, those problems decrease yield and increase costs.

“If you mix something in the wrong order, it can waste a whole tanker load of product,” Matt Geiger, Syngenta agronomy service representative for south-central Illinois, says. He strongly recommends that growers who plan to mix new products do a jar test before going all-in on a full tank. Using a 2-liter bottle or a mason jar, Geiger measures out the products in the tank-mix in smaller amounts at the same ratio in the planned tank-mix to test compatibility.

“For example, if you want to spray 3 quarts/A of Acuron¹ corn herbicide, you’ll need 200 milliliters in the jar to equal the 3-quart spray rate,” he says. “Then you add products at equivalent rates of what they’d be in the field.”

Geiger calls it the mini spray tank and it gives growers a visual on whether the mix is uniform, also referred to as homogeneous, or needs to be adjusted.

“You’re using that to see if you get any sort of what we call flocculation — chunks, basically,” he says. “If the mixture stays clear and doesn't get cloudy or get these flocculation-type pieces in there, you're good to go.”

However, if you mix something in the wrong order, “it can go to what we call ‘cottage cheese,’ and sometimes you can’t get it back,” Geiger adds.

More Agitation, Less Aggravation

Insufficient agitation can undermine even a good mixture, especially if it includes fertilizer, which has a higher bulk density than the herbicide. Geiger says products can separate in the tank if you're not agitating.

For example, he says if a grower mixes up an entire tanker load of herbicide plus liquid fertilizer and does not agitate it, there is a chance of nonuniform application of the product across the field, or fields. The first part of the field may get a higher rate of fertilizer and a lower rate of herbicide, and the opposite toward the end. Agitation, especially in complicated mixtures, is very important to get a uniform application of product.

In fact, it’s such a big deal that Syngenta has a group of scientists with diverse specialties dedicated to the successful application of products for every kind of crop. Their focus is dose transfer: ensuring active ingredients reach the plants with minimal off-target movement or unintended damage. Scientists also thoroughly assess which application tools growers need for the job.

The head of the application technology group, Ram Ramalingam, Ph.D., says product familiarity, equipment calibration, and nozzles set for proper flow rate and spray pattern are key to make the best possible applications.

“We want to minimize the amount of active ingredients left in the tank and the frequency that clogged filters or nozzles affect a grower’s ability to complete the process. We also look at whether products are compatible in the tank or have sedimentation issues,” Ramalingam says. The group does extensive testing to ensure various common products are compatible. If the group finds products are not compatible, they notify commercial colleagues right away to get the word out to growers.

Time and Temperature Work Against Efficacy

Water also matters with application, Ramalingam says, and it’s not just its quality or pH that impacts products.

“Temperature plays a huge role,” he says. “As it gets hot, the rate of hydrolysis increases, and if you leave a mix in the tank for extended periods of time in broad daylight, it could also get really hot inside. In terms of losing efficacy, both time and temperature play a major role.”

Timing is perhaps the most important factor in product efficacy.

“One of the biggest mistakes I see is folks trying to wait until the weeds come up to do their weed control programs,” Geiger says. “They call it row-and-go. They want to make sure they've got rows of corn before they spray their herbicides, but weeds are much easier to control if they aren’t out of the ground yet.”

It's a risky choice because weeds can emerge and surpass 4 inches in height rather quickly, which is over the labeled size for species like waterhemp on many herbicide labels.

And then it rains.

“If you're out of the field for three days, that could result in 3 to 4 inches of weed growth and then your weeds are off-label,” Geiger says. “It's a lot more challenging to control weeds after they emerge.”

Ultimately, these experts agree, growers can implement a few simple management steps to help mitigate potential crop management issues. Testing soil, careful product selection, and timely and accurate applications provide crops with the conditions they need to thrive.

A tool is only as good as the way it is used, Geiger says, and even the most efficacious products must be used properly to maximize performance.

¹Always consult the product label for complete use and application information.