How to grow high-yield apples? These essential growing techniques must be mastered

As we all know, scientific and reasonable soil, fertilizer and water management techniques are the foundation for high quality, high and stable yield in orchards and for the longevity of fruit trees. So how exactly is it done? Which high-yield apple growing techniques need to be mastered?

1. Promote vigorous root growth and increase absorption capacity

Strengthening roots is a long-term task in fruit tree production. It should start with young trees: by loosening the soil and building up soil fertility, a strong root mass is promoted. After the trees enter full bearing age, the focus is on protecting the root system and preventing the fibrous roots from dying back, so as to maintain a strong absorption capacity.

2. Apply fertilizer at the right time to increase nutrient supply

In the annual growth cycle of fruit trees, before June the leaves have not yet fully grown and their photosynthetic capacity is weak. The nutrients needed for bud break, flowering, leaf expansion and shoot growth come mainly from the tree's stored reserves. After June, new shoots stop growing, the leaves fully expand and leaf area reaches its maximum. The nutrients needed for flower bud differentiation and fruit enlargement are supplied by the products of leaf photosynthesis, and the tree's growth and fruiting enter a stage dominated by the use of assimilates produced in the current year.

Generally, in the apple growth cycle, the early growth stage is dominated by vegetative growth and requires more nitrogen. By June, when flower bud differentiation begins, phosphorus uptake increases sharply. By August, as the fruit enlarges and its sugar content begins to rise, a large amount of potassium fertilizer is needed. Fertilization management should adapt to this pattern. The amount of fertilizer applied should be determined by tree age and crop load.

3. Prune rationally to keep strong branches bearing fruit

1. Reduce the number of branches to concentrate nutrient supply and cut down on ineffective nutrient consumption. If too many branches are left per mu, nutrients will inevitably be spread thin and tree vigor will tend to decline. Through pruning, surplus useless branches are removed so that nutrients are concentrated and the retained branches receive more nutrition, which favors vigorous shoot growth and promotes tree rejuvenation. During full bearing age, keep 60,000-70,000 branches per mu and thin out all surplus branches.

2. Increase the replacement rate of new and old branches to keep strong branches bearing fruit: after entering full bearing age, fruiting branches age with the years and their fruiting capacity declines, so fruiting branches should be properly renewed. Because Fuji is sensitive to pruning, the traditional heading-back renewal method is unsuitable; with Fuji, once you head back it sends out watersprouts, and once it sprouts watersprouts the tree shape becomes chaotic and tree vigor falls out of balance. Therefore, renewal of Fuji fruiting branches is mainly done by replacement. For trees 8-10 years old in bearing, when branches become thin and weak and the fruit is small, make deep notch cuts on the branch near the branch axis at the rear part of the branch to stimulate vigorous long shoots; after a year of slack training to promote flowering, keep strong branches bearing fruit to raise yield and quality.

3. Promptly thin out slender branches and old flowering branches to reduce ineffective nutrient consumption and improve the tree's light penetration and aeration.

4. Strengthen the transformation of vigorous branches and train weeping fruiting branch groups to enhance fruiting capacity.

5. Keep an appropriate number of fruiting branches: follow the standard of leaving 1 fruit per 40 cm on large branch axes and 1 fruit per 20 cm on small branch axes, and thin out surplus branches.

4. Limit yield to promote the formation of plump flower buds

The main contradiction in tree growth is that between reproductive growth and vegetative growth. The phenomenon of alternate bearing objectively exists. In an on-year, the tree bears more fruit, and most of its nutrients are used for fruit growth, while less is used for flower bud differentiation, resulting in many but thin and weak flower buds. Therefore flower bud quality is poor and the fruit set from them is hard to grow large; this is the main reason the fruit is on the small side in an off-year. Conversely, in an off-year, because fruiting is limited, the tree has ample nutrients, which favors the formation of plump flower buds. Flower bud quality is good, and the following year's fruit is generally larger, so fruit is large in an on-year.

Once apples enter full bearing age, yield must be strictly controlled. On the one hand this can effectively improve fruit quality; on the other hand it prevents excessive fruiting from weakening tree vigor. According to site conditions, tree vigor and the capacity for fertilizer and water supply, keep yield per mu between 3,000-4,000 kg. For orchards with deep soil, fertile soil, irrigation available, sufficient fertilizer and vigorous trees, yield can be kept at around 4,000 kg; otherwise yield should be appropriately reduced. Controlling yield balances the nutrient supply for vegetative growth and reproductive growth, promotes the formation of high-quality flower buds and raises the proportion of large fruit produced.

5. Increase the tree's stored nutrients

There are two obvious peaks in fruit enlargement. In the early stage of fruit growth, enlargement is mainly based on an increase in cell number; in the later stage of fruit growth, enlargement is mainly based on an increase in cell volume. The number of cells is closely related to the tree's stored nutrients. Generally, the more stored nutrients a tree has, the more cell divisions occur and the more the fruit can grow large; conversely, it is unfavorable to fruit enlargement. Therefore, increasing the tree's nutrient reserves is a key measure for producing large fruit. Taking comprehensive technical measures to increase the tree's nutrients is the main content of later-stage management of apple trees.

In short, fruit tree management must pay attention to observation and follow the laws of fruit tree growth and development. As long as these technical points are handled well and problems in production are promptly summarized and identified, full bearing age will arrive on schedule.