The nutrient distribution of fruit trees is uneven. Generally, the parts with high polarity or vigorous metabolism get more nutrition and grow vigorously. Because of the different activities of different organs in different developmental stages, the nutritional competitiveness of different organs is inconsistent. For example, in the bud stage and flowering stage, it is mainly the competition between flowers and leaves. The growth of new shoots and the development period of young fruits are mainly the competition between new shoots and young fruits. The fruit expansion period of flower bud differentiation is mainly the nutritional competition between fruit and flower bud or the competition between excessive branches and leaves and flower bud and fruit. Excessive flowers and fruits inhibit the growth of roots, branches and leaves, affect the differentiation of flower buds and the growth and development of fruits. Excessive growth of branches and leaves inhibits fruit growth and flower bud differentiation.

The assimilation products made by leaves are first supplied to the local branches and the nearest branches and fruits, and the nearest branches get more, which is the phenomenon of "nearby supply" of nutrition. The assimilation products of vegetative branches can be transported to other short branches and fruiting branches on the same mother branch besides their own consumption.

Apples absorb nutrients three times a year. First, during germination, it mainly uses the nutrients stored in the previous year to transport them to germination and flowering, and then new buds and fruits flourish (the number of fruit cells increases). The two compete fiercely for nutrients, and the stored nutrients are decreasing day by day, so the assimilated nutrients in leaves can only be supplied locally. Second, during the flower bud differentiation and fruit expansion, photosynthetic nutrients produced by leaves are the main ones. Under normal circumstances, the contradiction between flower bud differentiation and fruit nutrition distribution is prominent. The contradiction between the growth of new shoots and the differentiation of flower buds is prominent in trees with too fast growth of new shoots. Third, when the fruit is ripe, the growth of branches and leaves has all stopped, the differentiation of buds and the growth of roots continue, and the nutrients absorbed by leaves and roots are mainly stored.

The relationship between vegetative growth and reproductive growth is mainly manifested in the relationship between the growth of branches and leaves of vegetative organs and the fruit development and flower bud differentiation of reproductive organs. Vegetative growth is the basis of reproductive growth. Only on the basis of suitable branches and leaves can more fruits be produced and good fruits be produced. Nutritional growth and reproductive growth compete for nutrients. If the branches and leaves grow too vigorously, they will use a lot of nutrients to inhibit the formation of flower buds, or cause flowers and fruits to fall, which will affect the development of fruits. If the growth of branches and leaves is weak and the accumulated nutrition is insufficient, it will also affect the formation of flower buds and fruit setting; On the other hand, excessive flowering and fruit consumption will weaken the growth of vegetative organs, weaken trees, reduce yield and quality, and inhibit the formation of flower buds.

Only by adopting reasonable cultivation measures, balancing the relationship between vegetative growth and reproductive growth, and keeping the amount of branches and leaves in a reasonable proportion can we achieve high yield, stable yield and high quality. When pruning, the strong trees are lightly cut and lengthened to make them blossom and bear more fruits, the length is controlled by the fruit, and the crown is topped by the fruit; Properly prune weak trees, less fruit, strengthen growth potential, and finally unify the contradiction of long fruit, so as to realize early fruit and early harvest of young trees and high quality and high yield of big trees.