What is potash fertilizer made of and in what forms? The use of these substances in agriculture occupies an important place, since potassium oxide is necessary for the proper development of many plants. Raw materials for the production of these products are obtained in the Urals in the form of salts of cainite, sylvinite, carlinite, sheinite, and others. Simple products (cainite and sylvinite), as well as substances with a more complex chemical composition, are isolated by grinding by mechanical means.
What potash fertilizers are produced by the modern chemical industry? This is primarily kalimagnesia (potassium oxide - up to 25-26%, magnesium content - about 11-18%, does not contain chlorine), calimag (potassium oxide about 24%, also does not have chlorine in its composition), potassium salt (combined formula of sylvinite and potassium chloride, potassium oxide - more than 40%, high chlorine content).
Potash fertilizers for tomatoes are mainly represented by potassium chloride and potassium sulfate. The first of them is a white crystalline powder, soluble in water. Potassium chloride is made from sylvinite by removing impurities, resulting in a concentrate with a high proportion of nutrients (up to 62% potassium oxide). The resulting substance does not absorb moisture well, therefore it does not cake, can be stored in plastic containers and is easily delivered to land.
Potash fertilizers for tomatoes in the form of potassium chloride are introduced in the fall, so that excess chlorine “leaves” the lower layers of the soil and is inaccessible to the roots of the plant. But another substance - potassium sulfate - has no such drawback as the chlorine content in the chemical composition, which allows it to be the most used fertilizer of this class at present.
Portions of potassium sulfate are used as main or spring-summer potash fertilizers for tomatoes. Their chemical composition (about three percent magnesium, 18% sulfur and about 50% potassium oxide) helps prevent leaf wilt and get a good harvest. The amount of fertilizer is selected individually in each case, depending on climatic conditions, soil acidity, stage of crop rotation, plant varieties and other fertilizers applied. For example, the introduction of manure (nitrogen group) reduces the efficiency of the assimilation of potash fertilizers. Alfalfa planted in front of tomatoes will take a lot of potassium from the soil, and cereals, on the contrary, are not sensitive to this element.
To potash fertilizers for tomatoes were as useful as possible, it is necessary to calculate the application rate. To do this, it is advisable to find out how much potassium is contained in the soil (you can order a study in special laboratories). Then you need to determine how much pure substance a given variety needs (say 20 grams of potassium per square meter) and calculate the required amount of fertilizer. In our case, so that the plant receives 20 grams. potassium should be taken, for example, 40 grams of potassium sulfate, because it only half consists of the oxide of the element we need. A simpler, but less accurate way to determine the norm is to follow the recommendations on the packaging of one or another type of fertilizer.