What is the correct method for foliar feeding of fruit trees?
1. Types, timing and amounts of spray fertilizer. 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 spray 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; decomposed...
1. Types, timing and amounts of spray fertilizer. 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 spray 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; the concentration for decomposed human excrement and urine is 0.5% in the early stage and 10% in the late stage. For phosphorus fertilizer spraying, follow the principle of less in the early stage and more in the middle and late stages. Ammonium phosphate gives 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%. Potassium fertilizer is 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, soak 0.5 kg of ash in 5-15 kg of water for 24 hours, then filter out the residue and spray.
Trace elements. If small leaf disease was found in the previous year, spray a 3%-5% zinc sulfate solution one month before fruit tree budding, and 0.15%-0.25% during the growing period. When leaves are found to lose green color and turn yellow-white, spray 0.3%-0.5% ferrous sulfate solution once every half month during the growing period. If fruits are found to shrink and become deformed with dry spots on the surface, spray 0.3%-0.5% borax solution before and after flowering the following year.
2. Spraying time. To extend the leaf absorption time and improve fertilizer use efficiency, foliar feeding should be done before 10 a.m. and after 4 p.m., and spraying on a partly cloudy, windless day gives the best effect. Spraying nitrogen fertilizer during full bloom can increase the fruit-setting rate; spraying nitrogen fertilizer during the young fruit stage can promote young fruit enlargement; spraying nitrogen fertilizer in May and June, combined with phosphorus and potassium fertilizers, 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.
3. Spraying method. Foliar feeding can be done alone, or several fertilizers can be mixed and sprayed together or mixed with pesticides to save labor. However, when mixing, pay attention that fertilizers or fertilizers and pesticides mixed together 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, for example, various trace element fertilizers must not be mixed with alkaline fertilizers or pesticides such as plant ash and lime, and zinc fertilizer must not 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, or bubbling occurs, it indicates they can be mixed; otherwise they must not be mixed. When foliar feeding, spray from top to bottom, evenly and thoroughly, mainly spraying the underside of leaves.