Among many elements we usually use, potassium fertilizer is the most important fertilizer. Potassium fertilizer is generally applied in the middle and late stage, which can sweeten and color the fruit due to the combination of phosphate fertilizer and accelerate ripening.
What kind of potash fertilizer is the best? In fact, it mainly depends on crops (such as watermelon, rice, sweet potato, corn, peach trees, etc. ), and determine what kind of potash fertilizer is the best time and use method. Today, I will explain to you the rational use of potash fertilizer.
Potassium fertilizers commonly used in the market are only potassium chloride, potassium sulfate, potassium nitrate, potassium dihydrogen phosphate and potassium phosphite.
1, potassium chloride
From the price point of view, potassium chloride is the cheapest, especially good in water solubility, and most suitable for field use. Because the salt content in potassium chloride is too high, most fields pass through the rainforest and have good salt tolerance, so using potassium chloride is the most cost-effective.
2. Potassium sulfate
Potassium sulfate is generally used in cash crops, and its price is slightly higher than that of potassium chloride. Generally, the price of potassium sulfate per ton is about 200 yuan higher than that of potassium chloride. However, potassium sulfate is an acidic fertilizer, and it will also cause soil acidification and root malabsorption when used in large quantities.
3. Potassium nitrate
Potassium nitrate is particularly water-soluble and generally suitable for topdressing, but the content of nitrate nitrogen in potassium nitrate is too high, with the content of 13.5%.
Although the content of 46% potassium fertilizer is already high, a large amount of potassium nitrate will cause the early fruit to expand rapidly, but it is difficult to color the late fruit, which is also the biggest disadvantage of potassium nitrate.
When it is used, a small amount of colored crops can be used in the early stage, and potassium nitrate is not recommended when it is mature in the later stage.
4. Potassium dihydrogen phosphate
Application of potassium dihydrogen phosphate in agriculture. There are many ways. Most of them are mainly applied by washing and foliar spraying. Potassium dihydrogen phosphate has a high content in both phosphate fertilizer and potash fertilizer.
Potassium dihydrogen phosphate contains 52% phosphate fertilizer, and 34% potash fertilizer is also a good water-soluble fertilizer. However, the dissolution of potassium dihydrogen phosphate has a certain saturation, which requires a lot of water to melt, and the dissolution time is slow.
At present, the best use in the market is instant potassium dihydrogen phosphate, that is, expanded potassium dihydrogen phosphate. This fertilizer is more soluble in water and easily absorbed by roots.
5. Potassium phosphite
Potassium phosphite is a new type of fertilizer in recent years. Because trivalent phosphorus in potassium phosphite has bactericidal effect when it is converted into pentavalent phosphorus, it is beneficial to plant disease prevention.
However, the conversion rate of phosphate fertilizer is low and the utilization rate of phosphate fertilizer is low. When using potassium phosphite, we must pay attention to the temperature problem. If the temperature is too high, it is easy to cause drug damage.
As for a small amount of potassium fertilizer, such as organic potassium, potassium carbonate, potassium polyphosphate, potassium pyrophosphate and so on. It is rarely used, so I won't explain it one by one today. Everyone should choose the right potash fertilizer according to their own plants and usage.