At present, the foliar dressing has been widely used in production, especially in the middle and late stages of crop growth, which has the advantages of low cost, quick effect, and obvious effect. In order to improve the effect of foliar dressing, based on years of production experience, the following seven points should be mastered.
1, determine the best spraying period. Different crops have different best fertilization periods. Spraying has a narrow area of ​​seedling leaflets, less fertilizer absorption, and a lot of waste. The effect is not ideal. Late spraying delayed yellowing and aging of the leaves, and reduced the function of sucking fertilizer. Delayed late spraying of some crops will also cause late-maturing glutinous crops, which will affect yield and reduce the value of commodities. Crops that are harvested based on years of experience, such as soybeans, corn, etc. From the initial flowering period to the filling period is appropriate. During this period, the plants grew vigorously, requiring large amounts of fertilizer, strong leaf absorptive capacity, and good spray fertilizer effects. Stem and leaf as the object of harvest, such as cabbage, should be in the opening period; celery should be 25-30 days before the listing as well. Melon and pod fruit crops have better effect during the expansion period. Spraying the fertilizer in the best period can effectively increase the fertilizer utilization rate and achieve the effect of increasing production and income.
2, determine the appropriate amount and concentration. The number of foliar sprays and the concentration of spraying are different for different crop types. According to the comparison of production tests, the amount of medical liquid per mu for grain crops is 30-40 kg and the concentration is 1-2%. The amount of medicinal liquid for stem and leaf mu is 45-55 kg, the concentration is 0.5-1%, the spraying frequency is 2-3 times, and the crop with many leaves and hairs can also be added with some adhesives when sprayed, such as washing powder and soap. Liquid, etc., to enhance the adhesion of liquid fertilizer on the leaf surface, to extend the suction time of the leaves.
3, choose a good spray of weather and time. The good and bad effects of foliar dressing are related to the weather, temperature, wind speed and time of spraying fertilizer. In different crops, the mesophyll cell structure is tight, the pore size and the development time are different. When the leaves are sucking fertilizer, they need certain temperature and humidity. According to the physiological habits of crop leaves, spraying the weather should be selected in the cloudy morning or sunny morning or after 4 pm, avoid high temperature and strong light irradiation at noon, so as to avoid excessive evaporation of liquid fertilizer affect the effect of suction. When spraying fertilizer, the temperature should reach 25-30°C, and the liquid fertilizer's water temperature should be 20-28°C. The water temperature and the low temperature will affect the spray fertilizer effect. In the weather with excessive wind speed, the effect of top dressing is also not satisfactory. In addition, rain should be sprayed within 2 hours after spraying.
4, foliar spray fertilizer method. When the foliage is sprayed with fertilizer, the front and back surfaces of the blade are sprayed and sprayed as the standard. Production operations are generally more sprayed on the leaves and slower absorption, while spraying fertilizer on the back is less suction fat. Therefore, when the leaves are sprayed with fertilizer, they should be sprayed as far as possible on the back surface.
5, the choice of spraying plots. Foliage dressing is generally better applied in the following plots. First, plots with poor crop root growth after flooding, insufficient base fertilizer for defermented plots in the later stages, and crops that are prone to or have a deficiency The third is the desire to obtain high-yield, high-impact land plots, such as greenhouse vegetables, corn, and rapeseed varieties.
6, the season of leaf dressing. The suction strength of the leaves is closely related to the temperature. Generally, high-temperature fertilizer absorbs more fertilizer, and low-temperature weather absorbs less or even no fertilizer. Seasonally, the foliar dressing is mainly from early spring to late autumn. From the stage of crop growth, it is mainly the period from vegetative growth to vegetative and reproductive growth.
7. Select the appropriate fertilizer type. Foliage dressing should be based on the needs of the crop to determine the type of fertilizer, symptomatic under the fertilizer, fast-improving quick fill. Generally soluble in water-soluble chemical fertilizers (nitrogen, phosphorus, potassium, micro-fertilizer), biological bacteria and other fertilizers, with the use of. Fertilizers can be applied individually or in several combinations. Some fertilizers can be mixed with pesticides when they are used for foliar spraying, while others cannot be mixed, such as biological bacterial fertilizers and fungicides.