Correct Methods and Techniques for Spraying Foliar Fertilizer on Fruit Trees
Spraying Period and Dosage 1. Nitrogen fertilizer should generally be used in the early and late stages of fruit tree growth, appropriately combined with phosphorus and potassium fertilizers. An appropriate spraying concentration can effectively promote new shoot growth, increase fruit yield, and benefit flower bud differentiation. The concentration for urea is 0.2-0.3% in the early stage and 0.3-0.5% in the late stage; for decomposed human manure...
Spraying Period and Dosage
1. Nitrogen fertilizer Generally, it should be used in the early and late stages of fruit tree growth, appropriately combined with phosphorus and potassium fertilizers. An appropriate spraying concentration can effectively promote new shoot growth, increase fruit yield, and benefit flower bud differentiation. The concentration for urea is 0.2-0.3% in the early stage and 0.3-0.5% in the late stage; for decomposed human manure, the concentration is 0.5% in the early stage and 10% in the late stage.
2. Phosphorus fertilizer The principle of less in the early stage and more in the middle and late stages should be followed for spraying. Ammonium phosphate has the best effect, at a concentration of 0.5-1%; the concentration for potassium dihydrogen phosphate is 0.2-0.5%; the concentration for superphosphate extract is 1-3%.
3. Potassium fertilizer Mostly used in the middle and late stages. It can effectively promote fruit coloring, improve fruit quality, and enhance disease resistance. The concentration for potassium sulfate and potassium nitrate is 0.3-0.5%; for plant ash, use 5-15 kg plus 0.5 kg of water, soak for 24 hours, then filter out the residue and it is ready for spraying.
4. Trace elements If leaves lose their green color and turn yellow-white, spray a 0.3-0.5% ferrous sulfate solution once every half month during the growing season. If fruits are found to be shrunken and deformed with dry spots on the surface, spray a 0.3-0.5% borax solution before and after flowering the following year.
Spraying Time
Spraying works best on a semi-cloudy, windless day, preferably before 10 a.m. and after 4 p.m. Spraying nitrogen fertilizer during full bloom can increase the fruit-setting rate; spraying nitrogen fertilizer during the young fruit stage can promote young fruit expansion; spraying nitrogen fertilizer in May and June, combined with phosphorus fertilizer, can effectively promote flower bud differentiation; spraying phosphorus and potassium fertilizers in the late stage can increase fruit sugar content and promote coloring; trace elements can be sprayed before and after the flowering period.
Spraying Method
Foliar spraying can be done alone, or several fertilizers can be mixed and sprayed together, or mixed with pesticides, to save labor. However, when mixing and spraying, care must be taken that the fertilizers, or the mixture with pesticides, do not cause fertilizer burn or pesticide damage. Urea is a neutral fertilizer and can be mixed with many pesticides. Pesticides and fertilizers with different acidity and alkalinity must not be mixed, such as various trace element fertilizers, which cannot be mixed with alkaline fertilizers or pesticides such as plant ash and lime; zinc fertilizer cannot be mixed and sprayed with superphosphate. Before mixing fertilizer with pesticide, first take a small amount of each solution and put them into the same container. If no turbidity, precipitation, bubbling or similar phenomena occur, it indicates that they can be mixed; otherwise, they must not be mixed. When spraying foliar fertilizer, spray from top to bottom, evenly and thoroughly, mainly spraying the undersides of the leaves.
The effective period of foliar spraying is generally only 12-15 days, and it needs to be done more than 2-3 times consecutively. Long-term spraying will affect root growth and weaken the physiological function of the root system, so on the basis of soil fertilization, foliar spraying should be used as an auxiliary measure for rapid nutrient supplementation.