How to topdressing crops can increase yield?

How to topdressing crops can increase yield? Please introduce the method of topdressing crops, which is an important means to increase production and income, but we must pay attention to science in topdressing in order to achieve the effect of high yield and harvest. Three basis: according to the different acidity and alkalinity of the soil, the types of chemical fertilizer to be applied should be determined. In general, acidic chemical fertilizers such as ammonium sulfate should be selected in low-lying alkaline land; basic or neutral chemical fertilizers such as urea, ammonium bicarbonate and ammonia should be applied in acidic soil; sandy soil and sandy loam with poor water and fertilizer conservation capacity should be applied with non-volatile ammonium chloride, urea and other chemical fertilizers. At the same time, during the topdressing period, it is best to increase the times of topdressing and reduce the amount of fertilizer applied each time, so as to prevent the volatilization and loss of chemical fertilizer. The mixed application of ammonium chloride and urea in paddy field according to the nature and composition of chemical fertilizer can inhibit nitrification and reduce leaching loss, but it should not be used in saline soil to avoid chloride accumulation in soil and aggravate salt damage. At the same time, it can not be applied to taboo crops such as tobacco, sugar beet and potatoes so as not to reduce its yield and quality. Urea is suitable for all kinds of crops and all kinds of soil, but it can release fertilizer effect and be absorbed by crops through transformation in the soil. Therefore, when using urea as topdressing, it should be several days earlier than other nitrogen fertilizers, and at the same time, the soil should be applied deeply to improve the fertilizer efficiency. To prescribe the right medicine according to the types of crops, according to the demand supply, such as corn needs more nitrogen fertilizer, the application of base fertilizer and seed fertilizer alone can not meet the crop's need for nitrogen fertilizer, but also timely catch up with a certain amount of nitrogen fertilizer; soybean is also a crop that needs more nitrogen fertilizer, root nodule nitrogen fixation can only meet about 50% of the nitrogen fertilizer needed by soybean during the whole growth period, and the effect of topdressing nitrogen fertilizer in time is very good. Sunflower (4.060, 0.10, 0.10, 2.40%) because of its high plant, deep roots and large disk, it needs more fertilizer than Gramineae crops and can be applied with urea. First, master the need to grasp the critical period and maximum efficiency period of all kinds of crop nutrients, so that the early topdressing of wheat in the peak nutrition period can obviously increase the yield, and nitrogen fertilizer should be applied once at the 3-leaf stage to lay a good foundation for the cultivation of strong seedlings and large panicles; soybean can be topdressing secondary nitrogen fertilizer at the early flowering stage, which can reduce the rate of flower and pod drop, prolong plant life, and increase grain weight and yield. The peak period of nutrition absorption of maize is from jointing to trumpet mouth stage, and the second fertilizer should be applied before heading, rice should be fertilized once at green stage, jointing stage and heading stage, and sunflower can be fertilized at budding stage. Click to get more compound fertilizer application techniques