What are the potash products? How should it be used? When should I replenish potash?

When it is time to supplement potash fertilizer, some farmers still do not know the importance of potash fertilizer, what potash products are and how they should be used, resulting in missing the opportunity to supplement potash fertilizer. Potassium is one of the three elements of fertilizer. Potassium in plants generally accounts for 0.2% of dry matter, 4.1% of dry matter, second only to nitrogen. Potassium participates in various life activities of plants in the process of plant growth and development. at the same time, it can also enhance the stress resistance and improve the quality of crops. In a word, potassium plays an important role in agricultural production.

1. Types of potash fertilizer

Potassium-bearing minerals, especially soluble potash mineral salts, are the main raw materials for the production of potash fertilizer, which can also be extracted from salt lake water, salt well water and brine.

⑴ 's nomenclature of potash fertilizer

Potash fertilizer belongs to a strong alkali acid salt, which corresponds to what acid radical it corresponds to, potassium nitrate corresponding to nitrate, potassium sulfate corresponding to sulfate, potassium chloride corresponding to hydrochloric acid, potassium carbonate corresponding to carbonate, and potassium phosphate corresponding to phosphate (monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, potassium polyphosphate, etc.). The organic potassium corresponding to the organic acid radical is called organic potassium (potassium formate, potassium acetate, potassium citrate, etc.), and the corresponding silicate radical is called potassium silicate.

Main products of ⑵

Plant ash-mainly contains potassium, phosphorus, calcium, magnesium, sulfur, silicon and various trace elements, but mainly potassium and calcium. It is a rapidly available alkaline potash fertilizer. Avoid rainy blisters when storing. Should not be mixed with ammonium nitrogen fertilizer, water-soluble phosphate fertilizer and fully mature organic fertilizer (such as human and animal urine) at the same time. Rich in calcium, can not be mixed with calcium superphosphate. It is suitable for all kinds of soils except saline-alkali soil, especially for acid soil. Plant ash can be used as base fertilizer, topdressing and covering seed fertilizer, as well as extra-root topdressing. The dosage is 50-100kg/ mu, and a small amount of water should be added to make it wet before application. When making base fertilizer, it is appropriate to apply it centrally, using ditch application or hole application, and covering soil after application. When topdressing, it can be foliar sprayed. When used as cover fertilizer, it is used as vegetable seedbed mulch. 1% plant ash water extract is used as extra-root topdressing to prevent aphids.

Potassium chloride-potassium content 60%, commercial fertilizer content 50% Mur60%, suitable for all kinds of soil except saline-alkali soil. Attention should be paid to the combined application of organic fertilizer, calcium magnesium phosphate fertilizer, phosphate rock powder or other alkaline fertilizer in acidic soil or soil with large amount of potassium chloride for a long time. Long-term application of potassium chloride in neutral soil should be combined with calcareous fertilizer. Potassium chloride should be applied reasonably or a small amount according to crop and soil conditions on melons and fruits vegetables and under protected cultivation conditions, and dichloride fertilizer made of potassium chloride and ammonium chloride is strictly prohibited. In the dry season, the amount of potassium applied to the soil needs to be increased appropriately. It can be used as base fertilizer and topdressing fertilizer, but not as seed fertilizer. When used as base fertilizer, it should be used in combination with organic fertilizer, phosphate rock powder and so on in neutral and acidic soil. Topdressing should be applied early, and the application rate is generally 5-15kg/ mu. The application amount of base fertilizer can be slightly more than that of topdressing. Chlorine-sensitive crops such as potatoes should not be used, potassium sulfate and other potassium fertilizers that do not contain chloride ions can be used. The advantages are low price, high potassium content, good fast solubility and neutral fertilizer. The disadvantage is that it dissolves and absorbs heat, absorbs moisture easily, contains chlorine, and a large number of long-term applications have certain side effects.

Potassium sulfate-contains 48% Mel 52% potassium, 18% sulfur, light gray or yellowish, soluble in water, high concentration of rapidly available potassium fertilizer, suitable for all kinds of crops and soils, especially suitable for chlorine-avoiding and sulfur-loving crops, such as potato, onion and garlic. In acid soil or long-term application, calcium magnesium phosphate fertilizer, phosphate rock powder or other alkaline fertilizer should be applied to prevent soil acidification and consolidation. It has a good effect on sulfur-deficient soil and vegetables that need more sulfur, such as onion, leek and garlic, so it should be used on crops that are sensitive to chlorine and like potassium and sulfur first. It is not suitable for use in aquatic vegetables. When applied in neutral and calcareous soils, organic fertilizers should be combined with organic fertilizers. For sandy soil with poor ability to conserve water and fertilizer, base fertilizer and topdressing should be combined and applied respectively. It can be used as base fertilizer, topdressing fertilizer, seed fertilizer and foliar fertilizer. It is suitable for early application as topdressing. The concentrated fertilization methods of strip application, furrow application and hole application were adopted as base fertilizer and topdressing, and the application rate was 7.5-15kg/ mu. The amount of fertilizer used for planting is 1.5-2.5kg/ mu. The concentration of foliar fertilization is 2% Murray 3%. The advantages are low price, high potassium content, not easy to absorb moisture, and can provide sulfur. The disadvantage is that it dissolves and absorbs heat, and it is weakly acidic, so it is a physiologically acidic fertilizer. The sulfur contained in it is easy to combine with calcium to form micro-soluble calcium sulfate, which can cause soil acidification and consolidation after application.

Potassium dihydrogen phosphate, which contains 52% phosphorus and 34% potassium, is a chemically neutral, physiologically neutral fertilizer with good water solubility. Generally, before and after flowering, it can be used to promote root germination and flower bud differentiation, provide energy for flowering and fruit setting; use during coloring period can promote powder coloring and increase fruit sweetness; use after fruit picking can promote branch ripening and improve fruit Lignification. It can be used for seed soaking, seed dressing, root dipping, root irrigation, foliar spraying and root application. It is economical and effective to use in the critical period of crop growth. Such as seed soaking and seed dressing before sowing, jointing stage, budding stage and booting stage of grain crops, and the best effect at seedling stage and full flowering stage of cotton, rape, peanuts, vegetables and potatoes. The advantage is that it is not easy to absorb moisture and the total content of phosphorus and potassium is high, so it is a necessary raw material for water-soluble fertilizer with high content of powder at present. At the same time, the supplement of phosphorus and potassium is less, and the effect is obvious. The disadvantage is that there are a lot of fakes, so please identify the regular manufacturers when you buy them.

Potassium nitrate, which contains 13.5% nitrate nitrogen and 46% potassium, is a chemically neutral and physiologically neutral fertilizer with good water solubility. long-term application will not lead to soil acidification. It is suitable for the expansion period of young fruit of fruit trees to the initial stage of coloring, and can promote the expansion of pulp cells. Due to the presence of nitrate nitrogen, it is not recommended to use it in the later stage of coloring, which is easy to turn green. It is easy to move in the soil, so it is suitable for topdressing crops, especially in the middle and late stages. The advantages are moderate price, good quick solubility, not easy to absorb moisture, neutral fertilizer, and fast absorption of nitrate nitrogen. The disadvantage is to dissolve and absorb heat to lower the ground temperature, which is easy to cause the accumulation of nitrite in crops under stress (prohibited in organic agriculture), which belongs to nitrate, and there are certain safety risks in the process of storage and processing.

two。 Effective application of potash fertilizer

The effective application technology of potash fertilizer is affected by many factors, such as soil type, fertility level, crop type, fertilization method and so on.

⑴ potassium application due to soil

The degree of potassium deficiency in soil is a prerequisite for the effective application of potassium fertilizer. first of all, the effect of soil available potassium content on the efficiency of potassium fertilizer should be considered. The fertilizer effect of potassium fertilizer is closely related to the abundance and deficiency of soil available potassium, that is, under the same other conditions, the lower the content of soil available potassium, the better the fertilizer effect of potassium fertilizer in the current season.

The soil with soil available potassium content less than 40 mg / kg is extremely deficient in potassium. Potassium has become a limiting factor for crop production and should be given priority to apply 5-10 kg per mu and 10-20 kg of potassium chloride or potassium sulfate no matter what kind of soil and crops. the effect of increasing yield is very significant. When the content of soil available potassium is 40-80 mg / kg, it is potassium-deficient soil, and the amount of potassium fertilizer per mu is about 5 kg. When the content of soil available potassium is more than 80 mg / kg, except for some cash crops that like potassium, food crops can be applied less or not. At the same time, the content of slowly available potassium, soil texture and ripening degree should be considered.

Soil slowly available potassium can not be directly absorbed and utilized by crops, and it is the source and backup of soil available potassium. When the content of soil available potassium is similar, the lower the content of soil slowly available potassium is, the slower the rate of conversion to available potassium is. Potash fertilizer tends to be more effective. However, as a guide for the application of potassium in the current season, the content of soil available potassium is the main basis.

Because of the low level of potassium in coarse sandy soil and the easy leaching loss of available potassium in soil, the effect of applying potassium in this kind of soil is often better than that in clayey soil, and the fertilizer effect of potassium fertilizer in high mature soil is generally lower than that in low mature soil. Because the former is rich in potassium, and has good soil physical and chemical properties, strong potassium supply capacity. The potassium content of soils in southern China is low, and the focus of potassium fertilizer application should be in the south, but the area of potassium deficiency in northern soils is gradually expanding, especially in some high-yield soils, the phenomenon of potassium deficiency is becoming more and more serious.

⑵ potassium application due to crops

Under the same condition of soil potassium deficiency, potassium fertilizer should be given priority to be used in potassium-loving crops, in the order of legume crops > potato, sugar beet, sugarcane, watermelon, fruit trees > cotton, hemp, tobacco > corn > rice and wheat. Potassium-loving crops are relative. No matter what crops are planted in the soils with serious potassium deficiency, the yield-increasing effect of potassium application is significant. In potassium-rich soils, potassium-loving crops often do not increase production.

The response of different varieties of the same crop to potassium fertilizer is also different. Taking rice as an example, the fertilizer efficiency of potassium fertilizer application of hybrid rice, dwarf and high yield stem rice is better than that of long stalk variety, Shantou rice and conventional rice.

Increasing or early application of potash fertilizer can enhance cold resistance, reduce freezing damage and increase yield of soybean, oil lai, wheat, fruit trees, rice and other crops in cold, drought, lack of sunlight and other harsh environment. For example, the contents of available potassium and slowly available potassium are higher in the black soil in Northeast China, but the experiments on soybean in recent years show that the application of potassium fertilizer can enhance the cold and drought resistance of soybean in cold and drought years, and the fertilizer effect is also obvious.

Application amount of ⑶ potash fertilizer

The amount of potash fertilizer also follows the phenomenon of diminishing returns. In potassium deficient soil, the yield of crops increased with the increase of potassium application, while the increase of yield per kilogram of potassium fertilizer decreased with the increase of potassium application. When the dosage exceeds a certain range, the output can not be further increased.

The suitable amount of potassium fertilizer should be determined by the content of soil available potassium, crop species and the balance of various nutrients. In the case of less potash fertilizer at present, it is generally unable to fully meet the needs of crops, and it is appropriate to use 3-6 kg potash fertilizer per mu. In potassium-deficient soils, it is generally possible to increase rice production by 5-10 kg per kilogram. The utilization rate of potash fertilizer in the current quarter is 40%, 50%. Crops with serious potassium deficiency and like potassium in soil, such as soybean, sweet potato, tobacco, sugarcane and so on, can be appropriately increased, while in plots where soil potassium deficiency is not serious and farmhouse fertilizer is sufficient, potassium fertilizer can be applied less or not.

Application period of ⑷ potash fertilizer

Potash fertilizer can be used as base fertilizer, seed fertilizer or topdressing fertilizer. Potash fertilizer is the same as phosphate fertilizer, the effect of base fertilizer or early topdressing is better, because the seedling value of crops is the critical stage of potassium and is very sensitive to potassium. Although the potassium absorption of crops at the seedling stage is less than 1% of the whole growth period, the individual at the seedling stage is small and the relative number is relatively large.

Application method of ⑸ potash fertilizer

After sowing, ploughing and pressing into the soil; strip fertilization with or near the seeds during sowing; shallow tillage (raking or weeding) after sowing; hole application; surface spraying; foliar spraying, etc.