At present, foliar top dressing has been widely used in agricultural production, especially in the middle and late stages of crop growth. It has the advantages of low cost, quick effect and good effect. In order to improve the effect of foliar top dressing, based on years of production experience, the following six key points should be mastered:

1. Determine the spraying period

Different crops have different spraying periods. Early spraying has small seedlings, narrow leaf area, and poor fertilizer absorption; late spraying leaves yellowing and aging, reducing fertilizer absorption, and some crops spraying late can cause greedy green and late maturity. Affect production and reduce commodity value.

2. Determine the appropriate dosage and concentration

The amount of fertilizer sprayed per mu for grain crops is about 30-40 kg, with a concentration of 1%-2%. The amount of spraying fertilizer for stems and leaves per mu is about 45-55 kg, the concentration is 0.5%-1%, and the spraying frequency is 2-3 times. When spraying crops with more hairy leaves, you can add some adhesives, such as washing powder, soap liquid, etc., to enhance the adhesion of liquid fertilizer on the leaf surface and prolong the fertilizer absorption time of the leaves.

3. Choose the weather and time for spraying

Different crops have differences in mesophyll cell structure, pore size, and unfolding time. The leaves need certain temperature and humidity to absorb fertilizer. The fertilizer spraying weather should be selected in the morning or after 4 pm on a cloudy or sunny day, and avoid high temperature and strong light at noon, so as to avoid the rapid evaporation of liquid fertilizer and affect the fertilizer absorption effect.

The temperature when spraying fertilizer should reach 25℃-30℃, and the water temperature of liquid fertilizer should be 20℃-28℃. Too low water temperature and temperature will affect the spraying effect. The effect of foliar topdressing in the weather with excessive wind speed is not ideal. In addition, it should be sprayed if it rains within 2 hours after spraying.

4. Selection of spraying plots

One is the plots where the base fertilizer is insufficient in the later stage. The second is the plots where crops are prone to appear or have some kind of deficiency disease. The third is to obtain high-yield, high-efficiency plots, such as nurseries, flowers, greenhouse vegetables, corn, rapeseed, etc.

5. The season of topdressing foliage

The strength of leaf absorption of fertilizer is closely related to the temperature. Generally, high temperature weather absorbs more fertilizer, and low temperature weather absorbs less fertilizer or even does not absorb fertilizer. In terms of seasons, topdressing of foliage is mainly from early spring to late autumn. From the perspective of crop growth stages, it is mainly the stage of vigorous vegetative growth to the stage of simultaneous vegetative growth and reproductive growth.

6. Choose the right type of fertilizer

Foliar top dressing should be based on the needs of crops to determine the types of fertilizers, fertilizer to the symptoms, quick effect and quick replenishment. It is generally recommended to use water-soluble foliar fertilizers containing amino acids.