The potato has the characteristics of potash-like. Which stage needs the most potassium?

Potato has the characteristic of potassium-loving and has a great demand for potassium, so more attention should be paid to the application of potassium fertilizer in cultivation. For every 1000 kg potato tuber, it is necessary to absorb 5 kg of pure nitrogen, 2 kg of phosphorus pentachloride and 10.6 kg of potassium chloride from the soil. The absorption ratio of N, P and K is 1 ∶ 0.4 ∶ 2.1.The production of potato tubers requires absorption of 5 kg pure nitrogen, 2 kg phosphorus pentachloride and 10.6 kg potassium chloride.

Topdressing potato

After the application of potash fertilizer, first, it can increase the swelling and pressure of cells, make the cells more elastic, and regulate the opening or closing of leaf cells, which is beneficial for potatoes to absorb more carbon dioxide to make carbohydrates and form starches and sugars. Second, it can promote root development, absorb more water, alleviate water evaporation and improve drought resistance. Third, it can promote the development of stem cellulose, improve stem support, enhance potato lodging resistance, disease and insect resistance, facilitate the transport of organic nutrients (starch) from potato to storage organs (underground rhizome and fruit), and accelerate root expansion. In order to increase yield and improve quality.

Potash fertilizer is generally applied in two ways: base fertilizer and topdressing fertilizer. Nitrogen, phosphorus and potassium fertilizers are distributed, with 50% nitrogen fertilizer, all phosphate fertilizer and most potash fertilizer in the base fertilizer. The variety of base fertilizer can choose the concentration universal compound fertilizer or the combination of elemental fertilizer. 50% nitrogen and a small part of potassium used for topdressing can choose urea, ammonium nitrate and potassium sulfate.

In the application, we should seize the period when the potato needs the most potassium. One is the seedling stage. Apply 3 kilograms of potassium chloride or potassium sulfate or plant ash (including 7.5% available potassium) 25 kilograms per mu as base fertilizer, spread evenly during soil preparation, and mix soil fertilizer. Potash fertilizer can also be applied in seedlings, strip application or hole application of 2kg potash fertilizer per mu, the depth is about 10~15cm, after fertilization, irrigation and covering soil. Second, in the stage of tuber formation. With the same amount of potash fertilizer per mu, after the tuber expands or pods are needled, the application of crack fertilizer and tuber fertilizer can effectively accelerate the perfusion of stem and leaf organic nutrients into potato lumps. In the later stage of potato growth, 1% potassium sulfate or 0.3% potassium dihydrogen phosphate or 5% plant ash water (after soaking for 24 hours, take its clarification solution or filter solution), spray outside the root twice (the interval is 7-10 days). Can reduce leaf temperature, conducive to drought resistance, elimination of diseases and insect pests (combined with the prevention and control of diseases and insect pests), the effect is very significant.

It should be noted that the time of topdressing should not be too early, generally in the potato expansion period. Early topdressing, especially after applying a large amount of nitrogen fertilizer, will lead to the growth of the aboveground part of the potato and the formation of small potato lumps in the underground part. Potassium chloride and potassium sulfate are physiological acid fertilizers. Long-term application should prevent soil acidification and can be applied together with appropriate amount of lime. Potassium chloride is not suitable to be applied in saline soil.