Organic Acids: Foliar Feeding and Plant Benefits
In 1947, Dr. William Albrecht wrote, “To be well fed is to be healthy.” This was as true then as it is today. For crops to be healthy, requires energy and nutrients, but crops can be no better (nutritionally) than the nutrient-template supplied them during the growing season. The supply depends on how available nutrient sources are for plant and crop use. Available means “plant-ready” or immediately ready for use. Applying “plant-ready” forms of nutrition helps your crop to be well fed. 
One way to feed your crop well, is by increasing the uptake efficiency of foliar nutrient applications. Uptake efficiency refers to the velocity of nutrient translocation from “source” to “sink”. A rapid plant and crop response is needed, at key stages of growth, to avoid crop and monetary losses. A foliar application that merely coats the canopy and isn’t absorbed is not efficient. Unless needed nutrients get into the plant and then into the fruit (sink), nutrient needs go unmet and complete benefit isn’t achieved. During the growing season, timing is a critical factor in crop development. For example, applying the right nutrition, at the right time, yields the right response, but the right nutrition applied late reduces the benefit or doesn’t help at all. Application timing is driven by temperature and nutrient availability (or unavailability) limits the efficiency of the growth process. Therefore a foliar spray application, with “plant-ready” nutrients, at the right timing, is a good option to ensure proper crop response.
Organic acids (O.A.) are not new to agriculture. In fact, they have been used for multiple decades because of the benefits they provide. While Humic acid (HA) and Fulvic Acid (FA) are classified as O.A., there are many more O.A. forms that are useful to growers; i.e. lactic, citric, gluconic, malic, etc. In Neoteric Agriculture, these are referred to as True Organic Acids (TOA), because of their high purity levels. Higher purity equals higher efficiency or “bio-availability”. TOA efficiency is due to their low molecular weight (small size). This makes them very effective natural chelators for more efficient nutrient translocation and growth response into plant and fruit tissue. Because TOA are in a “plant-ready” form, when combined with foliar nutrients, like calcium, magnesium, zinc, boron, etc., become “bio-available” as well. True Organic Acids also contain carbon rings, in their composition. Carbon buffers phytotoxicity risks in foliar nutrient applications and supplies a concentrated food (carbon-energy) source for plants and microbiology. On a pound for pound basis, True Organic Acids provide 2.25x more energy than sucrose.
Every stage of crop development is important and demands energy. This energy could come from stored carbohydrate reserves, foliar nutrient sprays, fertigations, etc. But, regardless of the source, if the energy runs short (energy deficit), it becomes the limiting factor to yield potential. All development stages are temperature driven; warmer temperatures speed stages up and cooler temperatures slow stages down. This makes early season nutrient decisions very time sensitive. Using “plant-ready” nutrient sources allows you to meet those nutrient demands in a timely manner more successfully and lessen the risks of energy deficiencies.
Foliar feeding is a proven way to supplement nutrition, especially when soil conditions cannot meet the demands of the plant development. For example, calcium is vital for good development, but in its elemental form it can’t supply plant energy unless combined with a carbon source like TOA. Calcium chloride (CaCl2) is a widely used and accepted calcium foliar-feeding source. It is water-soluble and proven effective, but the chloride must be factored into application rates to avoid plant tissue damage. When combined with TOA, the CaCl2 compound is split and the O.A. bond with both the calcium and chloride ions. This makes “bio-available” calcium as calcium lactate, -citrate or -gluconate and the chloride is carbon-buffered reducing phytotoxicity risk. Additionally foliar calcium is difficult to get absorbed into fruit versus leaves, as leaves are a much stronger calcium “sink” than fruit. This is why multiple foliar applications are needed, with fruit-surface contact through the growing season, for best efficacy. By incorporating a TOA, with your calcium foliar sprays, complete nutrient absorption is rapid for better plant health and fruit quality.
Plant leaves are an additional limiting factor to efficient plant uptake. You
know that foliar nutrient absorption rates are higher in young leaves versus old leaves. As leaves mature, a waxy cuticle develops, that layer serves to protect the plant. It helps to regulate evapotranspiration (ET) rates but also limits the amount of nutrient ion penetration. In many cases, the amount of epicuticular wax is greater with higher levels of environmental stress. This varies by species, but regardless, the waxy protective coating limits efficient foliar-nutrient uptake. Foliar nutrients combined with TOA are able to permeate the mature leaf cuticle because of their “bio-available” form and small molecular size. Their
size is small enough to be absorbed through the ectodesmata (plant pores) for a positive plant growth response. The ectodesmata are located on surface of leaves. The pore size is less than 1nm. These are much smaller than stomata and serve a different purpose. Because TOA are smaller than 1nm, this makes them an ideal nutrient chelator for higher absorption rates by plants and fruit. Synthetic chelating agents (EDTA, DTPA, EDDHA, etc.), are much larger molecules (higher molecular weight) and therefore not readily permeable into plant ectodesmata (pores), thus limiting nutrient uptake efficacy.
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| Cross Section of Leaf - P. Wojcik |
Ninety-five percent of plant mass is carbon, hydrogen and oxygen based
material (roots, wood, leaves, buds, fruit, etc.) and merely 5% is from other nutrients (fertilizer applications). Therefore nutrient focus should be on growing the healthiest canopy possible to take advantage of every daylight hour. Nutrient deficiencies limit photosynthetic efficiency and therefore plant and crop health. That’s lost opportunity. Applying foliar nutrients in “plant-ready” and “bio-available” forms supplements the crop when soil nutrient release is limited and supplies a rapid absorption response in order to maintain maximum yield potential. Both quantity and quality are a reality, when you foliar apply “plant-ready” nutrients with TOA, in your fertility plan.
Here’s to your crops’ success!
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