What are the methods of using foliar fertilizer?

What are the methods of using foliar fertilizer? Do you have any netizens to introduce to me the usual methods of applying foliar fertilizer? there are 7 main points to pay attention to. Please refer to the following list for details. First, symptomatic fertilization is needed: in order to promote early development or increase 1000-grain weight in the later stage, nitrogen and phosphate fertilizer can be sprayed; nitrogen and potassium fertilizer can be sprayed to increase leaf area and promote vegetative growth; and micro-fertilizer can be sprayed to prevent physiological diseases caused by lack of trace elements. Second, the selection of fertilizer types: the fertilizers with good effect of foliar spraying include urea, potassium dihydrogen phosphate, potassium nitrate, potassium sulfate, ammonium sulfate, as well as the leaching solution of calcium superphosphate and plant ash, ammonium metaphosphate and most trace element fertilizers. Third, the mastery of fertilization concentration: if the concentration is too high, it is easy to produce fertilizer damage and cause unnecessary loss; if the concentration is too low, it will not get the desired effect. The suitable concentrations for foliar spraying of common leaf fertilizer are as follows: urea 0.5%-2%, calcium superphosphate leaching solution 2%-3%, potassium dihydrogen phosphate 0.3%-0.5%, potassium sulfate 1%-1.5%, plant ash leaching solution 5%-9%, ferrous sulfate 0.2% 10%, boric acid 0.02% 0.1%, borax, 0.05% sodium 0.2%, manganese sulfate 0.0% 1.0%, Zinc sulfate 0.01% potassium 0.05%, ammonium molybdate 0.02% potassium 0.05%. It should be noted that different crops have different concentration requirements for different fertilizers. Take urea as an example, the suitable spraying concentration is 1.5%-0.8% on rice and other gramineous crops, and 0.4%-0.8% on sweet potatoes, potatoes and peanuts. 4. Spraying method: the amount of nutrients absorbed by leaves during foliar fertilization is related to the time of wetting leaves with solution. The longer the wetting time is, the more nutrients are absorbed by leaves, the better the effect is. In general, better fertilizer effect can be obtained by keeping the leaf wetting time at 30-60 minutes. Therefore, the most favorable time for foliar fertilization is in the evening when there is no wind, and it is not suitable for foliar fertilization on rainy days, before rain or in the morning with dew; if it rains within 3 hours after foliar fertilization, it should be applied once after sunny days, but the concentration should be appropriately reduced. Fifth, several times of spraying: the concentration of foliar fertilization of crops is generally low, and the amount of absorption is also very small each time. Therefore, the frequency of foliar fertilization should not be less than twice. The mobility of nitrogen and potassium fertilizer in crops is very strong, so it can be sprayed once in the critical period of crop growth, and the mobility of phosphate fertilizer is inferior to that of nitrogen and potassium fertilizer, which should be sprayed twice according to the growth status of crops. generally, zinc, molybdenum, manganese, copper fertilizer and immobile boron and calcium fertilizers which are only partially moved in crops should be sprayed continuously for 2 times. 6. the best position for spraying: the green stems and leaves of crops are reasonable parts of spraying fertilizer, especially the young and vigorous green functional leaves have the best effect of receiving fertilizer. It is worth noting that when spraying fertilizer on dicotyledonous crops, it is necessary to spray equally evenly on the front and back of the leaves, while monocotyledonous crops only need to spray fertilizer on the front of the leaves from top to bottom. 7. the method of mixed use of fertilizer: the reasonable mixing of two or more kinds of foliar fertilizer can save spraying time and labor, and the effect of increasing yield will be more significant. However, foliar fertilizer must be mixed without adverse reactions or reduce fertilizer efficiency, otherwise, not only can not achieve the purpose of mixed use, but also easy to produce fertilizer damage. What should be paid attention to when foliar spraying urea? click to get more foliar fertilizer application methods.