What is the correct method for spraying foliar fertilizer on fruit trees
Foliar feeding of fruit trees means mixing solid fertilizer into a water solution of suitable concentration and spraying it onto the leaves, so that it enters the tree through epidermal cells and stomata and takes effect. This method is simple and easy to carry out, uses little fertilizer, acts quickly, can meet the urgent nutrient needs of fruit trees, and helps correct nutrient deficiency symptoms. Scientific...
Foliar feeding of fruit trees means mixing solid fertilizer into a water solution of suitable concentration and spraying it onto the leaves, so that it enters the tree through epidermal cells and stomata and takes effect. This method is simple and easy to carry out, uses little fertilizer, acts quickly, can meet the urgent nutrient needs of fruit trees, and helps correct nutrient deficiency symptoms. Scientific application of foliar fertilizer to fruit trees can achieve twice the result with half the effort.
1. Choose the type of fertilizer according to its characteristics.
Fertilizers commonly used for foliar feeding that give good results include urea, monopotassium phosphate, potassium sulfate, potassium chloride, ammonium nitrate, ammonium phosphate, superphosphate, wood ash leachate, and some trace-element fertilizers. Fertilizers that volatilize easily, such as ammonium bicarbonate, are not suitable for foliar feeding.
2. Determine the spraying concentration and spraying period according to the type of fruit tree and the purpose of the topdressing.
The suitable concentrations for foliar feeding are generally: urea 0.3-0.5%, monopotassium phosphate 0.2-0.3%, ammonium phosphate 0.3-0.5%, boric acid 0.1-0.5%, borax 0.1-0.25%, ferrous sulfate 0.1-0.4%, wood ash 1-6%. To increase the fruit-setting rate of apples, pears, grapes, etc., spray 0.3-0.5% urea plus a 200-fold borax solution at the flowering stage; to promote fruit coloring, spray 0.2% monopotassium phosphate during the fruit-swelling stage; to increase the tree's nitrogen reserve nutrition, spray a high-concentration urea solution of 3-5% in autumn after fruit harvest. In the early stage of fruit tree growth, the fertilizer solution concentration should be low, and it can be appropriately increased in the middle and late stages.
3. Choose a suitable spraying time according to climatic conditions.
Foliar feeding should be carried out in relatively humid weather, and the fertilizer effect is best when the leaves remain moist for 30-60 minutes. To extend as much as possible the time the fertilizer solution remains on the leaf surface, it is best to spray in the early morning or evening when the air is humid and the dew has not yet dried; on a windless cloudy day, spraying can be done all day. If an appropriate amount of sticker is added to the fertilizer solution, the spraying effect can be noticeably improved.
4. Determine the number of fertilizer sprayings according to the movement of the fertilizer within the tree.
Nitrogen and potassium are highly mobile within the tree, so spraying once during the key growth period of the fruit tree is enough; phosphorus is less mobile than nitrogen and potassium, so it needs to be sprayed twice in a row according to the tree's growth conditions; zinc and copper are only partially mobile, and trace elements such as boron and calcium do not move, so they should be sprayed 2-3 times in a row to achieve the expected effect. In addition, while spraying foliar fertilizer, pesticides that can be mixed with it can also be added and sprayed together, which saves labor and time.