First, choose the right type of fertilizer. According to the growth and nutrition of fruit trees, choose the appropriate type of external fertilization. In the early or early stage of fruit tree growth, in order to promote growth and development, the fertilizers sprayed mainly include zinc sulfate, ferrous sulfate, calcium sulfate, potassium chloride, auxin, hormones, and nutrients. In the middle or late stage of fruit tree growth, in order to improve the nutritional status of fruit trees, the fertilizers applied on the foliar surface mainly include urea, potassium dihydrogen phosphate, superphosphate, potassium sulfate, plant ash, ammonium nitrate, ammonium sulfate and some trace elements.
Second, choose the appropriate spray concentration. Fertilization outside the root of the fruit tree, the concentration is appropriate, in order to receive good results, the concentration is high, not only unhelpful, but harmful, usually the appropriate spraying concentration of various micro-fertilizer solutions: urea 0.3-0.5%, ammonium nitrate 0.1-0.3%, Potassium dihydrogen phosphate 0.2-0.5%, ash ash 3-5% leachate, decomposed manure 1-3%, boric acid or borax 0.2-0.3%, zinc sulfate 0.1-0.4%, ferrous sulfate 0.1-0.4%, nitric acid Calcium 0.3-0.4%, potassium chloride 0.3%, if it is necessary to high concentration, not exceeding 20% ​​of the specified concentration (small area test and then spray).
Third, choose the appropriate spraying period. The period of fertilization outside the root of the fruit tree must be determined according to the use of the tree species and the micro-fertilizer. Generally, the external fertilization is sprayed during the growing season, while the plant ash is applied during the fruit expansion period. The zinc sulfate is used to prevent and cure the lobular disease before the germination. Boric acid and borax are sprayed at the flowering stage to increase the fruit setting rate. In order to reduce the loss of micro-fertilizer in the spraying process, it is best to spray on cloudy days, and on sunny days, choose to spray in the afternoon to evening without wind, in order to prolong the wetting time of fertilizer solution on the leaves of fruit branches and enhance the absorption of plants. Fertilizer effect. Spraying fertilizer in the morning with dew will reduce the concentration of the solution and affect the fertilization effect. If it rains 3 hours after spraying, it should be refilled once on sunny days, but the concentration should be reduced appropriately.
Fourth, determine the appropriate number of spraying. Due to the limitation of concentration and dosage, it is difficult to meet the requirement of micronutrient for growth and development of fruit trees in 1 year. Usually spray 2-4 times a year, each spray, the interval is at least 1 week. For the lack of trace elements in the soil and the serious lack of fertilizer for fruit trees, it should be sprayed several times, and pay attention to the combination with soil fertilization. As for the nutrients (such as iron, boron, calcium, phosphorus, etc.) that are small or not moving in the fruit trees, it is necessary to pay more attention to the number of spraying.
5. Select the appropriate spraying site. Fertilization on the outer surface of the root requires fine droplets. When spraying, it should be uniform, meticulous and thoughtful. Pay special attention to spraying on the back of the growing upper leaves and leaves, because the new leaves absorb nutrients more than the old leaves and the back of the leaves. Fast speed and strong absorption capacity. Especially for peaches, pears, persimmons, apples and other fruit trees, the front of the stratum corneum is 3-4 times thicker than the back. It should be noted that the back of the leaves should be sprayed for absorption. Therefore, the outer leaves are fertilized, and both sides of the leaves are sprayed.
6. Reasonably carry out external mixed spraying. The reasonable mixing and spraying of micro-fertilizers, or mixed with other fertilizers or pesticides, can play the role of "one spray and multiple effects". However, it is necessary to pay attention to clarifying the physical and chemical properties of fertilizers and pesticides. It should be tested first to prevent chemical reactions, reduce fertilizer efficiency or cause fertilizer and phytotoxicity. All kinds of micro-fertilizers should not be mixed with alkaline fertilizers. For example, all kinds of micro-fertilizers cannot be mixed with alkaline fertilizers such as grass ash and lime. Zinc fertilizer should not be mixed with potassium dihydrogen phosphate solution. When preparing the mixed spraying solution, generally, a micro-fertilizer is first formulated into an aqueous solution, and then other medicines and fertilizers are directly added to the pre-formulated micro-fertilizer solution according to the dosage, and the mixed solution should be sprayed with the accompanying solution.
Fertilization technology outside the roots of fruit trees
In addition to the nutrients absorbed by the roots, the leaves can also absorb nutrients. Foliar fertilization is also called fertilization outside the roots. Take root fertilization and grasp the types, concentrations, periods, times and parts of the fertilizers to make up for the lack of roots. Can achieve better yield increase effect.
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