What should we pay attention to when applying fertilizer?

What should we pay attention to when applying fertilizer? How can fertilization be beneficial to crops? We do not ask experienced netizens to introduce that China is a country with a large population and agriculture. Fertilizer plays an important role in feeding 22% of the world's population with 7% of the world's land. however, the long-term improper use of fertilizer will cause soil consolidation, salinization or volatilization and waste, so the farming network collates several key points that need to be paid attention to in the process of fertilizer application, which are listed in detail below for netizens' reference. Point 1, compound fertilizer is not suitable to be used alone: because the nutrients of compound fertilizer are relatively fixed, it should be used in conjunction with other chemical fertilizers according to the needs of different soils, different crops, different periods of plants for various nutrients, and according to the growth of crops at that time. For example, diammonium phosphate contains 18% nitrogen and 46% phosphorus, which is used in crops that need more nitrogen, the amount is calculated according to phosphorus, and the insufficient nitrogen is supplemented with ammonium bicarbonate and urea. Second, the effect of decentralized application of phosphate fertilizer is inappropriate: decentralized application of phosphate fertilizer is easy to be absorbed and fixed by the soil, thus losing the fertilizer effect. Therefore, the contact area between phosphate fertilizer and soil should be reduced, and ditch application or hole application can be used and concentrated near the root system of crops. Third, ammonium sulfate is not good for long-term use: because ammonium sulfate fertilizer is a physiological acid fertilizer, long-term application in a piece of land will increase the acidity of the soil, so it will destroy the soil structure. In alkaline soil, ammonium ion in ammonium sulfate is absorbed, while sulfate ion remains in the soil and reacts with calcium to harden the soil. Point 4, ammonium bicarbonate cover soil effect is the best: ammonium bicarbonate cover soil depth should be more than 6 mm, generally after application, covering soil is the best. In addition, ammonium bicarbonate is not suitable for application in the greenhouse, which is easy to decompose into ammonia and volatilize. Point 5. The effect of potassium fertilizer topdressing in the later stage is not good: because potassium is transferred from the lower stems and leaves of the crop to the young part of the top for reuse, it is better to apply potassium topdressing or one-time basal fertilizer at the seedling or jointing stage of the crop. What is the function of zinc sulfate? what is the function of potash fertilizer?