Matters needing attention in spraying foliar fertilizer of soybean

Foliar fertilizer spraying of soybean has the advantages of low dosage, quick effect, high fertilizer efficiency and good effect, so it has been widely popularized and applied in recent years. However, because some farmers mistakenly believe that foliar fertilizer spraying is "beneficial and harmless, the more the better", there are some problems in practical application, such as choosing fertilizer types at will, increasing the amount of fertilizer at will, determining the time of spraying fertilizer at will, increasing the number of times at will, and so on. It not only affects the effect of foliar fertilizer spraying, but sometimes even causes varying degrees of damage to plants. Therefore, in the implementation of foliar spraying fertilizer for soybean, we should pay attention to the following points: (1) types of fertilizer. To see the seedling fertilizer: if the plant growth is slow, thin, short, the leaf color is yellow, belonging to nitrogen deficiency, foliar spraying fertilizer should be mainly nitrogen, with a small amount of phosphorus and potassium fertilizer; on the contrary, if the plant is tall, tender green, internodes long, nitrogen nutrition is sufficient, foliar spraying fertilizer should be changed to phosphorus and potassium, can not remain the same. (2) the concentration of fertilizer solution. Different crops have different tolerance to different fertilizers at different times. If the concentration of fertilizer solution is too high, it will often cause fertilizer damage to burning leaves. Especially when the temperature is high, the principle of "low is not high" should be grasped in the range of suitable concentration. In addition, in the plant seedling stage, the leaf tissue is young, the concentration of spraying fertilizer should be lower, and the concentration of fertilizer deficiency should be higher; the concentration of trace element fertilizer should be lower, and the concentration of common element fertilizer should be higher. The concentrations of different foliar fertilizers are generally as follows: urea 0.5% Mel 2.0%, calcium superphosphate 1% Mel 5%, potassium dihydrogen phosphate 0.2%-0.5%, boric acid 0.1% Mel 0.5%, ammonium molybdate 0.02% Mel 0.05%, zinc sulfate 0.05% Mel 0.2%. (3) time of spraying fertilizer. In terms of fertilizer spraying period, fertilizer should be sprayed in the middle and later stages of growth and development when the leaf area is large, and the effect is the best. Spraying fertilizer when the plant leaf area is small, not only waste more fertilizer, but also the effect is not ideal. Molybdenum fertilizer should be sprayed before soybean flowering, while boron fertilizer and zinc fertilizer should be sprayed at the early flowering stage. In terms of fertilizer spraying time, it should be sprayed sooner or later in the hot sun after the leaf dew is dry on a windless cloudy day or sunny morning. If there are water or dew on the leaves when spraying fertilizer, it will reduce the concentration of fertilizer solution and can not achieve the effect of fertilization. If the fertilizer is sprayed in the scorching sun and high temperature, the air humidity is small, not only the volatilization and waste of the fertilizer solution is more, but also the fertilizer solution dries quickly after spraying, the leaves are difficult to absorb, and the fertilizer utilization efficiency will be reduced, sometimes because the water on the leaves evaporates too fast. the rapid increase in concentration caused "burning leaves". (4) the times of spraying. Many farmers think that the more times of foliar fertilizer spraying, the better. In fact, it is generally sprayed 2-3 times, and each time should be sprayed at intervals of more than 7-10 days. For trace element fertilizer, the spraying times should not be too much and the concentration should not be too high, otherwise it would not only fail to increase production, but also cause trace element poisoning. In addition to considering the above four factors, we should also pay attention to three points: first, although the amount of foliar fertilizer is small, it must be fully dissolved and stirred before spraying; second, the back of the plant leaf has less cutin, more stomata and is easy to absorb, so foliar fertilizer spraying should be mainly on the back of the leaf and supplemented by the foliar surface. Third, some foliar fertilizers can be mixed with fertilizers or pesticides, but many can not be mixed at will, otherwise it will affect fertilizer efficacy and efficacy, and sometimes cause damage to plants. The foliar fertilizer produced by our company is divided into four categories: compound foliar fertilizer is mainly made of agricultural ammonium molybdate, which is rich in nitrogen, phosphorus, potassium, calcium, magnesium, iron, boron, zinc, copper, ammonium polyphosphate and other trace elements, mainly suitable for soybean, wheat, rice, corn and other crops, spraying 60g or liquid 300ml per mu, water 25-30kg, so that crops grow luxuriantly, leaves are rich, particles are full, and the yield can be increased by more than 20%. Nutritional foliar fertilizer: mainly suitable for vegetables, melons and fruits, this kind of foliar fertilizer has high contents of nitrogen, phosphorus, potassium, molybdenum and more than ten kinds of trace elements, and its main function is to provide various nutritional elements for crops and improve the nutritional status of crops. it is especially suitable for the supplement of various nutrients in the later stage of crop growth. Plant foliar fertilizer is mainly suitable for tea, tobacco, flowers, fruit trees and so on. this kind of foliar fertilizer contains substances that regulate plant growth, such as auxin, ammonium polyphosphate, calcium, magnesium, molybdenum, iron, boron and so on. the main function is to regulate the growth and development of crops, make the foliar thickening and thickening of crops, etc., suitable for the early and middle stages of plant growth. Biological foliar fertilizer: this kind of foliar fertilizer contains microorganisms and metabolites, such as amino acids, nucleotides, nucleic acids, and its main function is to stimulate crop growth, promote crop metabolism, reduce and prevent the occurrence of diseases and insect pests.