Calcium-magnesium sulfate (K₂SO₄·MgSO₄) is an important concentrated mineral fertilizer, the advantage of which is the absence of chlorine, making it the optimal choice for chlorine-sensitive plants growing in various types of soils. The product is available in the form of grayish-pink or gray granules or powder, easily soluble in water.
Purpose of using calcium-magnesium sulfate
Main purposes of application:
- Replenishing potassium deficiency (K₂O) to increase crop yield. Potassium plays a key role in overall plant development, especially in the process of fruit, tuber, bulb, and root formation and filling.
- Improving crop quality. This element contributes to increased sugar and vitamin content in fruits, vegetables, and berries (such as tomatoes, cucumbers, grapes, fruit trees, potatoes, beets) and enhances their shelf life during storage.
- Enhancing stress resistance: strengthens cell walls, providing plants with greater resistance to lodging, drought, frost, and certain diseases.
- Compensating for magnesium deficiency (MgO) - an important element for photosynthesis that helps combat chlorosis. Magnesium is the central atom in the chlorophyll molecule. If there is a deficiency, the process of photosynthesis is hindered, and the plant cannot produce nutrients. Magnesium deficiency manifests as interveinal chlorosis - yellowing of the leaves between the veins, while the veins themselves remain green. Calcium-magnesium sulfate effectively addresses this issue since magnesium activates a series of enzymes responsible for the plant's metabolism and energy.
- Supplying sulfur deficiency (S) for active protein and amino acid synthesis, such as cystine, methionine, and others. Additionally, sulfur is necessary for synthesizing vitamins (B1, biotin), coenzymes, and chlorophyll. Sulfur contributes to a more efficient use of nitrogen by plants and participates in the production of plants' protective substances.
Calcium-magnesium sulfate is especially beneficial for chlorine-intolerant crops, such as vegetables (potatoes, tomatoes, peppers, eggplants, and cucumbers), berry bushes (currants, raspberries, gooseberries), and fruit trees (apples, cherries, plums).
Many crops also require potassium and magnesium:
- Vegetables: tomatoes, cucumbers, potatoes, peppers, cabbage, beets, carrots, onions, garlic, legumes.
- Fruits and berries: grapes, apple trees, pears, cherries, plums, strawberries, currants, raspberries, gooseberries.
- Ornamental and flowering plants: roses, peonies, lilies, conifers, lawn grass (especially in case of yellowing).
- Cucurbits: watermelon, melon, pumpkins.
Methods of applying calcium-magnesium sulfate
Calcium-magnesium sulfate is applied to the soil in autumn before fruiting or in spring before planting/seeding to provide plants with nutrition throughout the season. The dosage depends on the type of crop and soil fertility (usually 15-40 g/m²).
During the growing season, calcium-magnesium sulfate can be applied as a solution (15-25 g in 10 liters of water) or in dry form with subsequent watering, 1-3 times per season with an interval of 10-20 days, during periods of active growth and fruit formation.
Foliar application (spraying) is effective for magnesium deficiency (interveinal chlorosis). The solution is prepared less concentrated (10-20 g in 10 liters of water) and applied in cloudy weather or in the morning/evening, avoiding bright sunlight. It can be combined with other types of foliar application (except for calcium and phosphorus).
Calcium-magnesium sulfate is suitable for various types of soils but is most effective in light sandy and loamy soils, peat and acidic soils where magnesium deficiency is often observed.
It is important to remember that calcium-magnesium sulfate does not contain nitrogen and phosphorus, so it should be used in conjunction with fertilizers containing these elements, as well as organic matter (manure, compost).
Follow the recommended dosages, as an excess of potassium can impede the absorption of calcium and magnesium by plants. Consider the specific needs of each crop and follow the instructions on the packaging. Calcium-magnesium sulfate shows the best effectiveness in cases of actual potassium, magnesium, or sulfur deficiency in the soil, which can only be determined through soil analysis.
