As one of the three elements that require bentonite for plant growth, potassium fertilizer plays an extraordinary role, especially for tuber plants such as sweet potatoes, radishes, and potatoes, which are inseparable from potassium. Farmers are paying more and more attention to potassium fertilizers. Commonly used potassium fertilizers include potassium sulfate, potassium chloride, and potassium dihydrogen phosphate. However, potassium dihydrogen phosphate, as a phosphorus-potassium compound fertilizer, is usually used for foliar spraying. Here Let’s focus on potassium sulfate and potassium chloride. They are both potassium fertilizers, but what are their differences? Distinguishing the similarities and differences between the two is of great help for scientific fertilization.
Potassium dihydrogen phosphate: contains 52% phosphorus (P2O5) and about 34% potassium (K2O). It is a chemically neutral and physiologically neutral fertilizer with good water solubility. Generally, before and after flowering, it can be used to promote root germination and flower bud differentiation, and provide energy for flowering and fruit setting; use during the coloring period can promote powdering and coloring, and increase fruit sweetness; use after fruit picking can promote branch maturity and increase the degree of lignification of the fruit. Many people ask, which one is better, potassium nitrate or potassium dihydrogen phosphate? In fact, there is no such thing as which one is better. The key is how to use it. Both of them contain different elements. Potassium nitrate is a nitrogen-potassium binary compound fertilizer, and potassium dihydrogen phosphate is a phosphorus-potassium binary compound fertilizer. Therefore, different products should be used according to different periods. The nitrate nitrogen in potassium nitrate is easily lost by rain, so it is generally not recommended to be used in paddy fields. Regarding potassium nitrate and potassium dihydrogen phosphate, it can be understood that when crops require a large amount of nitrogen for growth, potassium nitrate is used; when crops require a large amount of phosphorus for growth, potassium dihydrogen phosphate is used. Use potassium nitrate during the expansion stage and potassium dihydrogen phosphate during the coloring stage. Use potassium nitrate during the normal growth period and potassium dihydrogen phosphate during the flowering and fruiting period. Strictly speaking, these two products cannot be regarded as simple potash fertilizers. Even potassium dihydrogen phosphate is classified as phosphate fertilizer in many categories.
Both of these fertilizers are quick-acting fertilizers, and the market price is higher than ordinary potassium fertilizers. Therefore, it is not recommended to be used as a base fertilizer, especially potassium nitrate, which is used as top dressing or extra-root fertilization. If possible, it would be better to use the two together. Many high-end water-soluble fertilizer raw materials will use these two things. Some friends said that water-soluble fertilizers using potassium nitrate and potassium dihydrogen phosphate as raw materials should be the conscience products of the industry.
The similarities between the two potassium fertilizers
Both potassium sulfate and potassium chloride are soluble in water and can be directly absorbed and utilized by crops. At the same time, they are all physiologically acidic fertilizers. When applied on acidic soil, they must be combined with alkaline fertilizers (calcium magnesium phosphate fertilizer, ammonium bicarbonate, plant ash), but cannot be mixed to prevent soil acidification. In addition, they are all inorganic fertilizers. The potassium ions separated after application can be adsorbed by soil organic matter. However, in soil lacking organic matter, potassium ions are easily lost with water, so they should be applied in conjunction with organic fertilizers and an appropriate amount of lime. Avoid affecting the structure and properties of the soil.
The difference between two types of potassium fertilizer
Potassium chloride: Contains high potassium oxide, generally 50% to 60% of non-foaming surfactant, can be dissolved in water, and has quick effects after application.
Potassium sulfate: Since potassium sulfate does not contain chloride ions, it has a wide range of applications and is suitable for a variety of chlorine-sensitive crops. It has a significant yield increase effect and can also improve product quality.
Differences in application scope
Application crops are different
Potassium chloride contains chloride ions, and its application in ramie and cotton fields can increase yield and fiber quality; however, when applied to chlorine-resistant crops that are particularly sensitive to chlorine, such as tea trees, tobacco, and ginger, the aroma will be reduced and the tobacco will be flammable. Deterioration; chlorine ions will reduce the yield and quality of chlorine-resistant crops such as beets, potatoes, sweet potatoes, and grapes. If these crops must use potassium chloride, it is best to compost it with organic fertilizer and then use it as base fertilizer, or apply it as early as possible. Potassium sulfate does not contain chlorine and has a wider application range than potassium chloride. It can be used in tobacco, sweet potatoes, sugar cane and other chlorine-resistant crops and cruciferous sulfur-loving crops, and is more effective than potassium chloride.
The application of soil is different
For rice fields with poor drainage and strong reducing properties, as well as rice fields where a large amount of undecomposed organic fertilizers are applied, potassium sulfate cannot be applied to prevent sulfide from reducing to hydrogen sulfide and poisoning the crop roots. Therefore, this type of rice fields are suitable for the application of potassium chloride. When potassium chloride is applied to rice fields, chloride ions are leached to the lower layers of the soil, which can avoid its adverse effects on crops. Moreover, chloride ions have a special inhibitory effect on Nitrosomobacterium in the soil, thereby reducing the denitrification loss caused by ammonium nitrogen fertilizers due to nitrification and denitrification. In the highly reducing rice field soil, the effect of applying potassium chloride is much better than that of potassium sulfate. For sulfur-deficient soils, such as paddy fields and cold soaked fields that are prone to floating mud after soaking in water and raking, potassium sulfate should be used.
Application methods vary
In addition to being used as base fertilizer and top dressing, potassium sulfate can also be used as seed fertilizer and root top dressing. The dosage of base fertilizer is generally 10 to 12.5 kg per mu, and the dosage of seed fertilizer is generally 1.5 to 2.5 kg per mu. The concentration of foliar spray fertilizer is 0.5% to 2%. However, potassium chloride cannot be used as base fertilizer and top dressing. Seed fertilizer and root top dressing, because chloride ions have a burning effect on seed germination and young stems and leaves. The amount of base fertilizer is generally 8 to 10 kilograms per mu, and the amount of top dressing is generally 5 to 7.5 kilograms per mu.
Potassium fertilizer has the function of enhancing cotton’s stress resistance and disease prevention effect. Therefore, insect-resistant cotton…�It is necessary to apply more potassium fertilizer.
