Calcium is an essential nutrient for plant growth. Almost 80% of fruit trees and vegetables have a high calcium demand. Root development, stem and leaf growth require significant amounts of calcium. Therefore, if you want your homegrown fruit to be of high quality and sell at a high price, it’s crucial to properly supplement calcium. Let’s take a look at the effects of calcium on crops and fruit trees.
A. The Importance of Calcium: Calcium is crucial because it participates in the formation of cell walls in the form of pectin. A calcium deficiency prevents cell wall formation, hindering cell division and the formation of new cells. Simply put, the beauty and appearance of fruit are closely linked to calcium. Calcium also influences the growth of root and stem apical meristems, affecting elongation, wood strength, seed germination, and the development of seeds and roots. Calcium prevents the extravasation of substances from cells and vacuoles, maintaining membrane integrity and preventing fruit from becoming soft and aging.
B. Harms of Calcium Deficiency: Calcium deficiency causes leaf color to fade, and young leaves lose their green color between veins and along their margins. Subsequently, pinhead-sized brown spots appear near the leaf margins. As the grapes grow, the leaf margins scorch, curl downward, and the top growth point of new shoots dies. Calcium also plays a crucial role in fruit growth. Calcium interacts with enzymes within the plant, preventing the outflow of pulp cell contents and the entry and growth of pathogens. Calcium in the fruit regulates the activity of enzymes involved in cell wall synthesis and degradation, reducing cell wall breakdown and maintaining fruit firmness and quality.
C. Types and Applications of Calcium Fertilizers
(a) Nitrate-Based Calcium Fertilizers: These primarily include calcium nitrate, calcium ammonium nitrate, calcium magnesium nitrate, and potassium calcium nitrate. These are the mainstream calcium supplements available for broadcast and flush applications. Advantages include affordability, good water solubility, and ease of use. As a neutral fertilizer, it doesn’t cause soil compaction or acidification, and its nitrate nitrogen is absorbed quickly, quickly showing its effects on leaves. However, there are drawbacks: Calcium ions in calcium nitrates are difficult to move, especially when sprayed evenly onto fruit for absorption. Furthermore, they should not be mixed with boron, potassium dihydrogen phosphate, or high-phosphorus water-soluble fertilizers, as reactions and precipitation can occur, affecting fertilizer effectiveness.
(b) Amino acid calcium: Amino acid calcium, also known as amino acid chelated calcium, uses amino acids as chelating agents to bind calcium ions. Plants can absorb calcium directly from amino acids, resulting in a higher absorption rate and better mobility than traditional calcium nitrates. Another reason for the effectiveness of amino acid calcium is that amino acids themselves have a positive effect on leaves and fruit, including sugar content, taste, and carbohydrate accumulation.
(c) EDTA Calcium: EDTA calcium is a calcium fertilizer chelated with EDTA. It is arguably the most efficient calcium fertilizer. It appears as a white, fluffy powder that crunches like snow when squeezed. EDTA calcium is very stable and does not readily react with phosphate or sulfate. It has excellent compatibility, eliminating the awkward reaction between calcium and boron. It can be transported up and down the plant body as EDTA moves. Because the raw material is relatively expensive and the calcium content is not very high, around 10%, finished EDTA calcium is relatively rare on the market. Manufacturers often use it as a raw material to produce chelated calcium fertilizers.
(d) Sugar Alcohol Calcium: Sugar alcohol calcium is a calcium fertilizer chelated with various sugar alcohols, such as mannitol and xylitol. Over 90% of finished sugar alcohol calcium fertilizers appear as a transparent blue liquid with a specific gravity of approximately 1.4-1.5. It is arguably the most mobile calcium fertilizer. Sugar alcohols are active components of plant protoplasm and are widely present in the phloem of plants. Plants treat sugar alcohols as their own, transporting them seamlessly throughout their bodies. They can be transported up and down the xylem and phloem in both directions, making them the only calcium fertilizer capable of this. Sugar alcohol calcium has become increasingly popular in the agricultural market in recent years, with increasingly affordable prices and widespread application.
(e) Other Calcium Fertilizers: Other calcium-containing fertilizers such as calcium magnesium phosphate, superphosphate, and quicklime are gradually being phased out. In contrast, silica calcium and calcined oyster shell powder are commonly used to condition acidic soils and supplement calcium. While calcium absorption and utilization rates are generally low, they are still effective in improving soil quality.
