A detailed guide to foliar fertilizer application methods: master the correct spraying techniques
What are the application methods for foliar fertilizer? Could any reader tell me about them? There are 7 main points to note when applying foliar fertilizer normally, and you can refer to the following list for details (for reference). 1. Fertilize according to the problem: to promote early development or increase the thousand-grain weight later, nitrogen and phosphorus fertilizers can be sprayed; to increase leaf area...
What are the application methods for foliar fertilizer? Could any reader tell me about them?There are 7 main points to note when applying foliar fertilizer normally, and you can refer to the following list for details (for reference).
1. Fertilize according to the problem:
To promote early development or increase the thousand-grain weight later, nitrogen and phosphorus fertilizers can be sprayed; to increase leaf area and promote vegetative growth, nitrogen and potassium fertilizers can be sprayed; to prevent physiological diseases caused by a lack of trace elements, microelement fertilizers can be sprayed.
2. Selection of fertilizer types:
Fertilizers that work well for foliar spraying include urea, monopotassium phosphate, potassium nitrate, potassium sulfate, ammonium sulfate, as well as the leaching solution of superphosphate and plant ash, ammonium metaphosphate, and most trace element fertilizers.
3. Mastering the fertilization concentration:
If the concentration is too high, fertilizer burn is likely to occur, causing unnecessary losses; if the concentration is too low, the desired effect will not be achieved.
The suitable concentrations for foliar spraying of commonly used foliar fertilizers are: urea 0.5%-2%, superphosphate leaching solution 2%-3%, monopotassium 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%-0.2%, manganese sulfate 0.0%-1.0%, zinc sulfate 0.01%-0.05%, ammonium molybdate 0.02%-0.05%.
It should be noted that different crops have different concentration requirements for different fertilizers. Taking urea as an example, the suitable spraying concentration on rice and other gramineous crops is 1.5%-2%, while the suitable concentration on sweet potato, potato, and peanut is 0.4%-0.8%.
4. Spraying method:
During foliar fertilization, the amount of nutrients absorbed by the leaves is related to how long the solution keeps the leaves moist. The longer the moist time, the more nutrients the leaves absorb and the better the effect. In general, keeping the leaves moist for 30-60 minutes is necessary to obtain a relatively good fertilizer effect.
Therefore, the most favorable time for foliar fertilization is on a windless evening. Rainy days, before rain, or mornings with dew are all unsuitable for foliar fertilization; if rain falls within 3 hours after foliar fertilization, apply it once again after the weather clears, but the concentration should be appropriately reduced.
5. Number of sprayings:
The concentration of foliar fertilization on crops is generally relatively low, and the amount absorbed each time is also very small. Therefore, the number of foliar fertilization applications should generally not be less than two.
Nitrogen and potassium fertilizers are highly mobile within the crop, so during key growth periods, one spraying is enough; phosphorus fertilizer is less mobile than nitrogen and potassium fertilizers, so it must be sprayed 1-2 times consecutively according to the crop's growth condition; zinc, molybdenum, manganese, and copper fertilizers, which are only partially mobile within the crop, and immobile trace fertilizers such as boron and calcium, should generally be sprayed 2-3 times consecutively.
6. Best spraying position:
The green stems and leaves of crops are the proper site for fertilizer spraying, especially the young, tender, vigorous green functional leaves, which receive the best fertilizer effect. It is worth noting that when spraying fertilizer on dicotyledonous crops, the front and back of the leaves should be sprayed evenly, while for monocotyledonous crops it is enough to spray the fertilizer solution from top to bottom on the front of the leaves.
7. Fertilizer mixing methods:
Reasonably mixing two or more foliar fertilizers can save spraying time and labor, and the yield-increasing effect will also be more significant. However, after mixing foliar fertilizers, there must be no adverse reaction or reduction in fertilizer efficiency; otherwise, not only will the purpose of mixing not be achieved, but fertilizer burn is also likely to occur.
What should be noted when spraying urea on leaves
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