At present, there are mainly potassium chloride, potassium sulfate, potassium nitrate and potassium dihydrogen phosphate in the market, which are widely used.
Characteristics of potash fertilizer
1. potassium chloride
Potassium chloride is a kind of quick-acting potassium fertilizer, which is easily soluble in water, and its content is about 60%, showing white, light yellow or purplish red crystals. It has good physical properties and can be used as base fertilizer and topdressing. The application of potassium chloride in acidic soil should be combined with lime and organic fertilizer.
Characteristics: Potassium chloride contains 50%~60% potassium oxide, which is a quick-acting fertilizer and is often used as base fertilizer and topdressing.
Advantages: low price, high potassium content and good instant solubility.
Disadvantages: chlorine, single long-term use is easy to cause soil hardening; Not suitable for saline-alkali land, it will aggravate the degree of saline-alkali land.
What are the potash fertilizers?
2. Potassium sulfate
Potassium chloride is a white crystal, easily soluble in water, and its content is about 50% ~ 52%. Besides being used as base fertilizer and topdressing, it can also be used as topdressing outside the root, and the suitable concentration of topdressing outside the root is 0.2%.
Features: Potassium content is about 50%, and sulfur content is about 18%. Potassium and sulfur are both essential nutrients for crops, and they do not contain chlorine, so they are more suitable for various soils and crops as base fertilizer and topdressing.
Advantages: low price, high potassium content, and sulfur besides potassium.
Disadvantages: It is a physiological acid fertilizer, and its sulfur is easy to combine with calcium to form slightly soluble calcium sulfate, which can cause soil acidification and hardening after application.
3. Potassium nitrate
Potassium nitrate is a colorless crystal with low hygroscopicity, easy caking, good physical properties and convenient use. It is a good water-soluble potash fertilizer.
Characteristics: Potassium nitrate contains 13.5% nitrate nitrogen and 46% potassium. It is a chlorine-free, potassium-free and nitrogen-free compound fertilizer made by dissolving sodium nitrate and potassium chloride together and then recrystallizing.
Nitrate nitrogen and potassium contained in it are essential elements for crop growth. Suitable for topdressing.
Advantages: moderate price, good instant solubility, belonging to physiological neutral fertilizer, which is generally not easy to cause soil acidification after long-term use.
Disadvantages: It is easy to cause the accumulation of nitrite in crops under adversity (organic agriculture is forbidden), which belongs to nitrate and has certain safety hazards during storage and processing.
The types, functions and characteristics of commonly used potash fertilizers are introduced.
note:
(1) In practice, potassium nitrate should not be mistaken for pure potassium fertilizer to avoid excessive application of nitrogen fertilizer to some crops.
(2) The nitrogen contained in potassium nitrate is nitrate, which is easily leached by water and difficult to use in paddy fields.
(3) It is the raw material for manufacturing gunpowder. During storage and transportation, special attention should be paid to preventing high temperature, and remember to contact with flammable substances to prevent explosion.
4. Potassium dihydrogen phosphate
Potassium dihydrogen contains 52% phosphorus (P2O5) and about 34% potassium (K2O). It is a chemically neutral and physiologically neutral fertilizer with good water solubility.
Characteristics: Phosphorus content is 52%, and potassium content is about 34%. Potassium dihydrogen phosphate can be used as base fertilizer, seed fertilizer, topdressing and seed soaking.
Advantages: the content of phosphorus and potassium is high, and phosphorus and potassium are supplemented at the same time, with less dosage and obvious effect.
Disadvantages: The disadvantage is that the price is higher and there are more fakes on the market.
Authentic potassium dihydrogen phosphate is relatively expensive because of its high effective nutrients. If the low-priced products must be counterfeit products, you should pay attention when you buy them.
The nutritional function of potassium can improve the intensity of photosynthesis, promote the formation of starch and sugar in crops, enhance the stress resistance and disease resistance of crops, and improve the absorption and utilization of nitrogen by crops.