Calcium
Calcium Introduction:
Growing nutrient-dense, high-quality fruits and vegetables is a challenge for growers every year. As you know, there is not one nutrient that is a “silver bullet” to ensure high-quality is a certainty, but applying calcium at the right stage of development plays a significant part in improving quality in all crops. The need for calcium during early development is critical for all fruit, nut and vegetable crops. But, let’s consider apples, where cropload and nutrient availability both play significant roles in plant health and crop quality.
Fruit Respiration and Mineral Uptake:
“Calcium is particularly critical for fruit quality and postharvest storability. Calcium is taken up more rapidly in the first half of the season, during the cell division period. As the fruit grows and a thicker waxy cuticle forms there is progressively less calcium uptake. This means that as the fruit is expanding but taking up less and less calcium, the calcium concentration in the fruit declines as harvest approaches. It has been found that uptake of calcium depends on the spur leaf area associated with the fruit. Again this focuses our attention on the early season activity. Early thinning removes fruit competition and therefore helps calcium uptake of the retained fruit.”1
Calcium at the Fruit Level:
“At the fruit level, Ca2+ movement from the peduncle towards the distal fruit tissue is also affected by different mechanisms, which define Ca2+ concentration in the distal-end tissue and fruit susceptibility to Ca2+ deficiency disorders. In the fruit, total tissue Ca2+ concentration decreases from the peduncle towards to the distal end tissue (Lewis and Martin 1973; Nonami et al. 1995). Accordingly, distal fruit tissue is more susceptible to Ca2+ deficiency disorders than fruit tissue at the peduncle region and Ca2+ deficiency symptoms usually begin in the distal tissue, eventually spreading to the whole fruit in severe cases (White and Broadley 2003; Ho and White 2005).”2
Timely applications of the needed nutrients for productive early development are critical for maximizing crop quality and plant health.
Source versus Sink:
What is a Source?
During early development, the primary source of nutrients and energy is the plant-stored reserves. This supply is accumulated in the previous growing season through nutrient management, plant photosynthesis and canopy nutrient resorption prior to dormancy. This supply is needed to sustain plant and crop development until the canopy matures and begins photosynthesizing and the soil temperature warms to 68°F for soil-fixed nutrient release to commence. But, these reserves can be supplemented with applications of “bio-available” nutrient formulations to improve plant development and crop quality.
What is a Sink?
“Developing apple fruits produce practically no carbohydrates themselves so they demand a continuous supply of carbohydrates from elsewhere in the tree. Another way of saying this is that fruit are a sink for carbohydrates. The carbohydrates required for early season growth of spur leaves, shoots and fruit during the period from bud break until bloom come from the remobilization of reserves that were accumulated in the previous year. Most of the reserves are used to fuel growth of the rapidly expanding spur leaves since they also are a sink for carbohydrates during this time. However the reserves in the tree are usually depleted by about bloom…
“Apple fruit are carbohydrate sinks for the entire season. Furthermore, during much of the cell division phase fruit are weak sinks, meaning they are not able to compete for carbohydrates as well as other sinks on the tree, particularly growing shoots.”
“Fruit are weaker sinks than shoots, so when the level of carbohydrates in the tree is low then fruit production can be limited due to a slowing down of the fruit growth rate. If there is a severe limitation in the supply of carbohydrates to growing fruit then they may even start dropping from the tree…”3
What is “bio-available”?
"Bio-available" refers to nutrients that are in a form readily absorbable and usable by plants. In this case, it means that calcium has been microbially-digested and converted into an ion-form of calcium. When a nutrient has been microbially-fermented and absorbed into the cells of microbes the nutrient becomes “bio-available.” A “bio-available” nutrient which has been absorbed into the cell of a microbe will also be readily absorbed into a plant cell. This significantly increases nutrient uptake efficiency. A natural byproduct of the microbial-fermentation process in the production of low-molecular weight organic acids (LMWOA), which are collectively called, “Bacillic acids.” These Bacillic acids bond with the calcium being microbially processed, which forms lactate-bound calcium. This nutrient-acid calcium formulation is 100% “bio-available” and designed to be fertigated or band-applied to moist soil where hair roots readily absorb it and translocate it via the xylem stream into the plant system. Based on 2021 WSU research, “... several studies have proven the ability of plant roots to directly take up small organic molecules such as low molecular weight organic acids (LMWOA), sugars, or amino acids, indicating that organic fertilizers of this nature could represent a direct source of nutrients for plant uptake.”4
What are Bacillic Acids and how do they interact with calcium?
Bacillic acids (BA) is a collective description of low-molecular weight organic acids (LMWOA) including lactic, citric, gluconic, and malic acids.
Here's how Bacillic acids interact with calcium:
Chelation: BAs can "grab and hold" or chelate calcium ions. This means they can bind to calcium to ensure efficient root absorption and plant translocation.
Preventing Binding: BAs like lactic acid can bond with calcium ions, preventing them from binding with other elements like phosphorus. This helps keep calcium available for plant and crop use.
Ionic-Calcium: Calcium lactate, calcium citrate, and calcium malate are examples of pure (ionic) calcium forms that are very effective and bio-available due to their association with BAs.
Bio-availability: When calcium hydroxide is added to a BA like lactic acid, it results in a fermented and naturally acidified calcium nutrient formulation, making it a "bio-available" molecule.
Plant Uptake: BAs have the proper pH and charges for efficient uptake and prevents calcium ions from attaching along the xylem pathway, which thereby ensures they reach the necessary sink in the plant.
Energy Boost: BAs can provide an energy boost to plants (bio-available carbon), which upon plant absorption releases pure ionic-calcium for plant use.
Through the use of lactate-bound calcium ,we have helped growers apply the needed calcium via fertigation or banded soil application in a single treatment. If you would like additional information about improving your crop quality, through the use of “bio-available” calcium, from Axiom Ag, contact us at the link below.
Here’s to your crops’ success!
References:
Lakso, Alan N. and Goffinet, Martin C. 2013 Apple Fruit Growth. New York Fruit Quarterly Vol. 21, No. 1, Spring 2013 http://www.hort.cornell.edu/expo/proceedings/2014/Tree%20Fruit/Apple%20Fruit%20Growth%20Lakso.pdf
Sergio Tonetto de Freitas, Elizabeth J. Mitcham, Book Editor(s):Jules Janick 2012 Factors Involved in Fruit Calcium Deficiency Disorders. Horticultural Reviews Vol. 40, 2012 https://doi.org/10.1002/9781118351871.ch3
McArtney, Steve. 2011 Apple Growth and Crop-load Management. Fruit Notes Vol. 76, Winter, 2011 http://umassfruitnotes.com/v76n1/a3.pdf
Opdahl LJ, Lewis RW, Kalcsits LA, Sullivan TS, Sanguinet KA. Plant Uptake of Lactate-Bound Metals: A Sustainable Alternative to Metal Chlorides. Biomolecules. 2021; 11(8):1085. https://doi.org/10.3390/biom11081085
