Calcium nutrition for fruit trees supports yield and quality

(Sponsored) Blink twice and it’s May. 2021 is moving quickly. But it’s not too late to plan calcium nutrition strategies for fruit trees and maintain yield potential across tree fruit, says agronomist Francisco Rivera of California-based OMEX® Agrifluids.

“You never know how a year’s going to turn out,” Rivera said. “But that uncertainty doesn’t mean you can’t plan ahead as far as nutrition is concerned. If you’ve made sure to give the tree all it could possibly need in terms of essential nutrients and elements, then you’re priming it to deliver the best possible yields. If you don’t give a tree the best, it can’t deliver the best.”

Rivera explained that fruit demands a wide range of nutrients, and heavy crops can leave trees dangerously low. “Nitrogen for vegetative growth and bud formation; potassium for growth, water optimization and fruit development; and calcium for high-quality, disease-free fruits,” he said. “Among these, calcium nutrition for fruit trees is the one to watch.

The golden rules of calcium

Rivera outlined three golden rules of calcium nutrition for fruit trees.

Rule 1: Crops cannot store excess calcium.

Unlike potassium, calcium cannot be stored long-term. “Once trees top-up their calcium storage in the calmodulin proteins between the cell wall and membrane, any excess is ejected through the leaves, even if fruit is deficient,” Rivera explained.

This makes testing unreliable. “Not only is there no connection between leaf tissue calcium and fruit tissue calcium, but the difference between acceptable levels and deficiency can be as small as 2ppm — outside any analytical tolerances.”

Rule 2: Calcium only moves upward.

“Plants can move it from one place to another because it’s not phloem mobile,” Rivera said. Instead, calcium travels through the xylem, following water. This explains why drought, waterlogging, or wind can lead to calcium-related quality problems such as bitter pit in apples.”

Rule 3: Auxin controls calcium uptake.

Rivera noted, “Calcium transport into cells is directly influenced by plant hormone auxin. If there’s no auxin present, crops won’t absorb calcium properly, irrespective of how much is applied.”

Developing fruit absorbs calcium well, but as fruit matures and cell expansion replaces cell division, calcium uptake declines rapidly.

Technology to improve calcium absorption

Understanding these rules helped British agri-tech company Levity Crop Science create new technologies to improve calcium nutrition for fruit trees. Through a partnership with OMEX®, growers in the U.S. now have access to LimiN® and LoCal®.

“This technology is like nothing else in the market,” Rivera said. “When we evaluated the Levity tech as an additive to our own products, we couldn’t wait to incorporate them.”

• LimiN®, used in Cell Power® SizeN®, stabilizes amine nitrogen to emphasize root growth and a compact habit, improving a tree’s ability to supply calcium to fruit.
• LoCal® mimics auxin, allowing crops to absorb calcium even when uptake would normally be limited. It is used in Cell Power® Calcium Gold and Calcium Platinum.

Product recommendations for fruit growers

For apples and pears, Rivera recommends starting with Cell Power® SizeN® K, applied four times at two quarts per acre through drip irrigation. “This reduces nitrogen from other sources while increasing fruit load and size,” he said. Growers should also apply Cell Power® Calcium Gold or Calcium Platinum up to five times at two quarts per acre, beginning at flowering, to reduce bitter pit and russeting.

Cherries and stone fruit benefit from four applications of Cell Power® SizeN® at two quarts per acre to maintain roots, shape, and fruit load. Rivera suggests applying Cell Power® Calcium Gold and Calcium Platinum at flowering. “Apply at 1 pint/acre, then top up after two weeks with a final one ahead of harvest. This will reduce cracking and increase yield.”

Learn more at www.OMEXusa.com.

The product names and brands referenced here are registered and trademarks of OMEX® Agrifluids, Inc.

© OMEX® Agrifluids, Inc. 2021.