One. What kind of fertilizer is used for top dressing？

The top dressing can use urea, potassium sulfate, potassium nitrate, potassium dihydrogen phosphate, etc., and also can use a large number of element water-soluble fertilizers for extra-root dressing. Amino acids and trace elements can also be added to the fertilizer to promote the growth and development of crops. Generally speaking In addition to applying base fertilizer before planting, it can also be used for top dressing during the growth stage.

Two, top dressing method

1. Spread directly

After the crops are watered and rained, when the soil in the field is suitable and the soil is suitable for the ground, sprinkle the fertilizer directly between the rows of the crop. Although this method is more convenient, it will cause a small amount of fertilizer to volatilize, especially ammonium bicarbonate. Strong fertilizers, such as urea, potassium sulfate, and ammonium sulfate, can be sprayed directly, but they are only suitable for inconvenient field operations and when crops require more fertilizer.

2. Watering with water

When watering, fertilizer is applied to the soil with water, but it will cause waste and is easy to lose. The fertilizer efficiency cannot penetrate into the deep layer of the root system. The advantages are fast, labor-saving, time-saving, and labor-saving. It is suitable for sufficient fertility and large planting area. , Spreading when the labor contradiction is prominent, when planting crops in a large area, when there is a serious shortage of fertilizer, the first top dressing method can be adopted.

3. Deep buried fertilization

(1) Dig pits between plants and rows of crops, and then cover the soil after applying fertilizer. This method is less wasteful and more economical. However, the disadvantages are labor-intensive, inconvenient operation, and heavy labor. It is necessary to pay attention to the ditch and pit where the fertilizer is buried, and it should be more than 10cm away from the root base of the crop. If it is too close to the rhizome, the root system will be damaged.

(2) Because the fertilizer is concentrated and the concentration is large, this method is not suitable to be used during the period of vigorous crop growth and the summer when more water is needed. It can be used in the winter season, when the labor force is sufficient, and the crop growth is low. The fertilizer in the soil gradually dissolves and supplements the nutrients needed by the crop.

(3) The peak period of crop growth is often the peak period of fertilizer and water demand. Therefore, deep burial fertilization is generally used when the temperature is high. After fertilization, water must be carried out to reduce the concentration of fertilizer buried in the soil.

4. Mechanical application

(1) At present, drip irrigation technology has been widely promoted, and fertilization automation has gradually begun to spread. The specific method of topdressing in drip irrigation facilities is: install fertilization machines at the part where water flows into the drip irrigation main pipe, and dissolve the fertilizer in the fertilization machine to dissolve the drip irrigation. The main pipe is put into the suction pipe filter of the fertilizer applicator, and then the fertilizer can be watered and automatically flow into the soil of the crop roots.

(2) This method is generally not easy to volatilize due to the mulching film. Although the fertilizer is concentrated, the concentration is small and there is no loss. It saves labor and labor and has good fertilizer efficiency. This is a top-dressing method with great development prospects in recent years. It's just that the input cost is too high, so it is rarely used in large-scale production.

5. Extra-root topdressing

(1) Extra-root topdressing is spraying foliar sprays. When planting crops, the artificially created environment is more conducive to supplementing the nutrients needed by crops and can promote the growth of crops. It has the advantages of high yield and multiple results. It can be combined with spraying and topdressing foliar fertilizer to meet the nutritional needs of crops. The amount of extra-root topdressing is small, the fertilizer effect is fast, and it can also prevent the effective components in the fertilizer from being fixed by the soil, which is an economical and effective fertilization method.