Calcium, magnesium and sulfur play a major role in plant physiology and a continuous supply is required to maximize yield and quality at harvest. Omya processes pure, high quality raw materials into ultrafine powder for highly efficient products. Available as granules, liquid or powder formulations, our products can be applied precisely using standard equipment to give maximum flexibility for the grower.
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All plants rely on a readily available supply of 17 key nutrients for productive growth and development (Epstein and Bloom, 2005). Carbon, hydrogen and oxygen are available to the plant through the air and water, whilst the remaining nutrients must be accessible from the soil. The three key secondary nutrients are calcium, magnesium and sulfur.
These elements are essential for plant structure and energy generation and, although they are needed in smaller amounts than the macro-nutrients, nitrogen, phosphorus and potassium, significant quantities of each are still required throughout the growing season.
Nutrients are transported from the roots to the rest of the plant via the xylem and the more mobile nutrients can be relocated to other parts of the plant in times of deficiency. Calcium has low mobility and sulfur becomes immobile when it is integrated into other molecules, therefore a continual supply of both must be available from the soil.
Lack of calcium affects cell wall structure and strength, leading to collapse of cell walls. For example, in crops such as lettuce or cabbage, calcium deficiency results in the margins of inner leaves turning brown and becoming necrotic, known as tipburn. In fruiting plants, blossom end rot is caused by calcium deficiency.
Sulfur is a constituent of the amino acids cysteine and methionine, which are used to build up proteins. These two amino acids are known as ‘essential’ amino acids, as they are unable to be produced by animals further up the food chain. Livestock therefore rely on plants for cysteine and methionine. Sulfur is also necessary for the synthesis of coenzymes, chlorophyll and secondary plant compounds. As a constituent of sulfolipids, it is a structural component of biological membranes.
Magnesium is essential for the transport of carbohydrates from the leaves to the roots. Plants deficient in magnesium will break down chlorophyll to access more magnesium, visible as interveinal chlorosis in older leaves, resulting in lower photosynthetic rates and ultimately poorer plant and crop performance.
Most nutrients are readily available to the crop at pH between 6 and 7 but, where soils become more acid, plant nutrition will be impaired as macro-nutrients become unavailable for uptake. Soil nitrogen, for example, stays in forms that plants find difficult to assimilate or, if transformed too late, are lost through leaching. In acid soils, phosphates are tied up, remaining inaccessible to the plant, and the potassium remains fixed to soil clays.
