Why is deep application of chemical fertilizer the main factor in improving fertilizer efficiency?

Deep application of chemical fertilizer is a fertilization method based on the crop's nutrient requirements and soil properties, using formulated fertilization techniques and the principle of the fertilizer rhizosphere effect, applying chemical fertilizer to a certain depth in the plow layer so that crops can absorb it better, reducing volatilization losses of fertilizer, and improving fertilizer use efficiency. The effect is even better when mechanized deep application of chemical fertilizer is used. Mechanized deep application of chemical fertilizer means completing the deep fertilization operation at the same time as mechanized plowing, soil preparation, sowing, and intertillage, using mechanical methods to control technical indicators such as the depth, position, and quantity of fertilization. Because the deeply applied chemical fertilizer is distributed within the effective rhizosphere range of the crop, it helps the crop absorb it better and reduces volatilization losses caused by surface or shallow application of chemical fertilizer. The average utilization rate of nitrogen fertilizer can be increased from 30% to 40%; deep application of phosphorus and potassium fertilizer can reduce wind erosion losses, promote absorption, extend fertilizer effectiveness, and generally increase yield by 5%—15%. Mechanized deep application can also avoid burning seeds, improve efficiency, and reduce pollution. Deep application of chemical fertilizer can be divided into three types:

Deep application of base fertilizer

There are two methods for deep application of base fertilizer: first, spread the fertilizer and then plow; second, apply the chemical fertilizer into the furrow while plowing, with the second method being better. The required fertilization depth is 6 cm, the fertilizer band width is 3—5 cm, and the fertilizer discharge should be uniform and continuous with no obvious breaks.

Deep application of seed fertilizer

When applying seed fertilizer deeply, a certain thickness must be formed between the seed and the fertilizer, generally more than 3 cm, to meet the crop's nutrient needs during the seedling stage and avoid the risk of burning seeds and seedlings.

Deep application of topdressing

Deep application of topdressing means making small furrows or holes 10—20 cm from both sides of the plant rows, with a depth of 6—10 cm and a fertilizer band width of more than 3 cm, and paying attention to covering with soil after fertilization.