This article appears in the July 2021 issue of Potato Grower.

The best agronomists put real store into advising growers of the importance of a “playbook” for potato nutrition: what’s needed, why and when. So now that we’re into the season proper, here’s an overview of four products that should feature in your own potato nutrition playbook this year.

Cell Power Zynergy

Zynergy, a combination of copper, zinc and organic acids, is formulated to enhance bioavailability — how easily the potato plant can absorb and utilize the product. Dean Konieczka, consultant agronomist for Omex Agrifluids, says Cell Power Zynergy is ideal within an integrated crop management program.

“It enhances fungicidal activity,” he says, “because copper and zinc play vital roles in the crop’s immune system. Zinc maintains the integumentary system (comprising epidermis, leaf cuticle and plant hairs). It’s the plant’s first defense against physical damage and pathogenic attack. High levels of zinc help the plant be quick to suppress disease and exhibit rapid wound healing.”

Konieczka continues: “Copper is crucial in the production of phenolic compounds, a large group of plant metabolites that influence plant growth and defense mechanisms.”

Research from Nottingham University in the United Kingdom shows how Zynergy’s formulation enhances bioavailability of these micronutrients. Replicated trials observed how copper and zinc components improved the crop’s ability to withstand disease, including late blight.

Zynergy was compared against tank-mixed zinc oxide and copper sulfate, and the contact fungicide mancozeb. On a virulent strain of blight introduced to inoculated potato leaves, the formulated product outperformed the standard mix of copper and zinc, while both Zynergy and mancozeb held back the infection satisfactorily.

Applied to the variety Maris Piper, Zynergy produced a 14.5 percent increase in marketable yield when used in conjunction with fluazinam and a foliar feed.

“But remember, Zynergy is registered as a fertilizer, not a fungicide,” points out Konieczka. “It’s an additive, not a substitute, so don’t be tempted to cut back on any fungicide programs. Just use Zynergy for the benefits it brings to an integrated crop management system.”

Cell Power Size N

Cell Power Size N enables potato growers to more accurately meet their contract obligations. Its unique nitrogen formulation is an effective tool to manipulate tuber size and increase marketable yield.

A stabilized amine nitrogen (SAN) technology, Size N leverages recent research that revealed how plant regulatory functions are affected by different forms of nitrogen. By using appropriate types of nitrogen at each plant growth stage, growers can use nitrogen more effectively and efficiently.

Applications of urea amine to potato plants results in increased root production, reduced stem elongation, increased chlorophyll content and raised chlorophyll levels at bulking. Under typical circumstances, soil bacteria attack urea and prevent uptake by the plant. But Size N contains a chemically stabilized amine that remains available to the plant, in both foliar and soil-applied form.

“By compiling a revised fertilizer application featuring SAN, growers can better meet the demands of each market,” says Omex CEO Mike Williams. “For example, making SAN applications early — pre-tuberization — will increase numbers of smaller tubers between 1½ and 2½ inches. But if growers omit that early application and apply SAN at bulking stage, they’ll see an increase in the percentage of larger tubers in the 2½- to 3¼-inch category.

“This shift in yield content does not come at the price of a smaller yield number or weight,” says Williams. “Yield is increased over and above that attained using standard agricultural practice.”

Cell Power Slyce

The same expectation to get more from less forms part of the inspiration behind the recently introduced Cell Power Slyce, while also promising to help growers protect crops from extreme weather patterns.

Slyce is a liquid formulation, containing calcium nitrate and humic acid. Offering increased soil-available fertility and rapid nutrient release, it boosts crops’ defense against stress and disease. In trials, it provided the most efficient calcium delivery — crucial for plant structure above and below ground — against any other standard source.

“Slyce works on the plant and in the soil,” Williams says. “Applied after granular fertilizers such as DAP, MAP or KCl, it allows faster and more efficient release of their components.

“Increasing soil’s organic matter,” Williams continues, “Slyce enhances nutrient, water-holding and aeration capacities, while helping to regulate soil pH, allowing beneficial fungi to thrive. Slyce also promotes chlorophyll development and mobilizes potassium — essential in respiratory function — to boost crop resilience against hot weather and drought stress.”

Cell Power Damu

Potato growers know how a good yield relies on a precise balance between top growth and tuber development. And vegetative growth demands nitrogen. But as nitrate levels increase, so too do levels of the hormone auxin, leading to increased top growth at the expense of tuber development.

But the more nitrogen a plant absorbs, the more deficient it becomes in boron. So a vicious circle begins: Plants deficient in boron make even higher levels of auxin.

To address this, growers need to increase leaf boron status, which in turn increases the levels of cytokinins and gibberellins, which gives greater focus to root and tuber development. However, timing and quantity must be just right; boron has a fine line between deficiency and toxicity.

“This is where Damu comes into play,” says Konieczka. “It’s a high efficiency product that allows lower rates of boron to be more effective. It employs stimulants to increase the speed of uptake, as well as the pace of metabolism within the plant.”

Used during periods of excess vegetative growth, Damu can reduce auxin production and refocus on the crop on root growth.

“Used at a low rate during the bulking period, Damu will help growers maintain proper tuber development during periods of rapid growth,” Konieczka says. “They can also use it at a higher rate ahead of harvest to bulk tubers more quickly.”