Best Times and Techniques for Fertilizing Fruit Trees, with Fertilization Techniques for Apple, Peach, Pear and Lychee

At present, many fruit growers in fruit tree growing areas lack relevant knowledge and have an insufficient understanding of the importance of fertilizing fruit trees, which may lead to reduced fruit tree yields and quality. So what are the best times and techniques for fertilizing fruit trees? The details are introduced as follows:

Main Misconceptions About Fertilizing Fruit Trees

1. The closer the fertilization point is to the tree, the better

Many fruit growers believe that if fertilizer is applied far from the tree, the roots will absorb it poorly and the nutrients will not be used, so they apply fertilizer very close to the tree, some less than half a meter from the root crown, and even dig out skeletal roots. The result is that root injury and root burning often occur, and the effect is often contrary to what was intended.

2. The more fertilizer, the better

Some fruit growers do not determine the amount of fertilizer comprehensively based on factors such as fertilizer type, tree vigor, tree size, yield and soil fertility conditions, but instead act blindly and think that the more fertilizer, the better. The result is an imbalance between tree nutrient supply and demand. In severe cases, roots are burned and trees die, and pests and diseases breed; in mild cases, vegetative growth and reproductive growth are imbalanced, with only trees growing, few fruits setting, or even no fruit at all.

3. Fertilization time based on busy and idle periods

Some fruit growers do not fertilize according to the fertilizer-demand period of the fruit trees, but according to whether labor is busy or idle. “When the trees need fertilizer there is no time to apply it, and when people are free the trees do not need fertilizer.” Fertilization that should be done in spring becomes summer fertilization, fertilization that should be done in autumn becomes winter fertilization, pre-flowering fertilizer that should be applied becomes post-flowering fertilizer, and post-flowering fertilizer becomes post-fruiting fertilizer. The best fertilizer-demand period of the fruit trees is missed, and the yield-increasing effect is greatly reduced.

4. Fertilizer types chosen arbitrarily

Autumn application of base fertilizer in orchards happens to conflict with autumn fertilization for wheat fields. Many fruit growers therefore arbitrarily use chemical fertilizers instead of base fertilizer, or use undecomposed crop straw instead of farmyard manure such as stable manure. Year after year this leads to reduced orchard fertility, weakened tree vigor, lower yield and poorer fruit quality.

5. Emphasis on underground fertilization and neglect of aboveground fertilization

Many fruit growers are accustomed to underground fertilization and either neglect or fail to clearly understand the role of aboveground fertilization, that is, foliar spraying. This leads to serious occurrence of physiological diseases such as yellow leaf disease, little leaf disease, fruit shrinkage disease and early defoliation disease, and reduces the photosynthetic function of leaves.

Correct Methods for Fertilizing Fruit Trees

1. The distance from the tree and the depth of fertilization should be appropriate

Fruit tree root systems are distributed over a very wide range. Generally, the horizontal roots of fruit trees are distributed 2-4 times the diameter of the canopy. Practice has shown that for fruit trees such as apple, pear, peach and apricot, the distance from the trunk when digging trenches or holes should preferably be at the outer edge of the vertical projection of the canopy, with a depth of 30-40 cm. At this position, the absorbing roots of the fruit trees are concentrated, and nutrient use efficiency is high.

2. Fertilization amount should suit the tree, the site and the fertilizer

Whether it is base fertilizer, slow-release fertilizer or quick-acting fertilizer, the general principles for determining the application rate are: young trees less than mature large trees; trees that have not fruited or are in the early fruiting stage less than trees in full fruiting stage; plots with poor fertility should receive more than relatively fertile plots. When applying autumn base fertilizer, the amount of stable manure applied is generally not less than 5000 kg per mu, of which high-quality and efficient chicken manure should not exceed 4000 kg. Long-acting complete compound fertilizers, microelement fertilizers and the like should be mixed into the base fertilizer, while chemical fertilizers such as urea, diammonium phosphate and potassium sulfate should be applied in split doses according to the different growth and development stages of the fruit trees. Where conditions permit, formula fertilization is encouraged.

3. Fertilization period determined by the tree

The fertilization period should be determined according to factors such as the different growth and development stages of the fruit trees, tree species and varieties. When busy farm work conflicts, fertilizer should still be applied even if workers must be hired, and the nutritional requirements of the trees must not be affected. For deciduous fruit trees, base fertilizer should generally be applied after fruit harvest or before harvest. Many fruit growers apply base fertilizer before the soil freezes or after it thaws in spring, which is very unscientific. Practice has shown that applying base fertilizer after fruit harvest or in the late stage of fruit maturity is of great significance for improving the photosynthetic function of fruit tree leaves, improving fruit quality and the level of nutrient storage in the tree, and enhancing the tree's stress resistance. Missing this period for base fertilizer application not only gives poor results, but may even have adverse effects. In addition, when tree vigor is weak, it may be applied earlier; when tree vigor is relatively strong, it may be applied later; for tree species and varieties that shed leaves earlier, it may be appropriately applied earlier.

4. Determination of fertilizer types

Fertilizer types should generally be determined according to factors such as the fertilizer requirements of the fruit trees and the types of fertilizers. Fruit trees need not only major element fertilizers such as nitrogen, phosphorus and potassium, but also microelement fertilizers such as boron, iron, zinc and copper. These nutrient elements come from organic fertilizers such as farmyard manure, crop straw, cake fertilizer and chicken manure, and also from chemical fertilizers such as urea, diammonium phosphate, potassium sulfate and various compound fertilizers. Only by combining organic fertilizers with chemical fertilizers, and major element fertilizers with microelement fertilizers, can the growth and development needs of different fruit trees at different stages be met. Overcome the practices in production of emphasizing nitrogen and phosphorus fertilizers, slighting potassium fertilizer, and neglecting organic fertilizers and microelement fertilizers.

5. Combine underground fertilization with aboveground fertilization

Underground fertilization is the main channel of fertilization, but because soil readily fixes certain nutrient components, the fertilizer use rate is reduced. Aboveground fertilization, that is, foliar spraying, is applied directly to the tree and has the advantages of saving cost and labor, rapid nutrient absorption and high use efficiency. It is especially effective against physiological diseases such as yellow leaf disease caused by iron deficiency, fruit shrinkage disease caused by boron deficiency, little leaf disease caused by zinc deficiency, and early defoliation disease caused by reduced leaf function. Therefore, attention should be paid to aboveground fertilization, and underground fertilization should be combined with aboveground fertilization.

Now that you have seen the correct fertilization techniques for fruit trees, next we will introduce the fertilization techniques for apple, peach, pear and lychee respectively!