Key points of autumn pruning techniques for growing apples

1. The physiological characteristics of autumn: 1. In the late stage of shoot nutrition (August to November), a large amount of light and products from leaves were transported downwards into buds, fruits, branches and roots. 2. It is in the fruit ripening stage, including early, middle and late ripening varieties. 3. In the late stage of flower bud differentiation, continuous physiological differentiation and morphological differentiation. 4. It was in the late trough period of root growth (high temperature and trough period from July to August), autumn peak period from August to October and peak period after fruit harvest. 5. the whole tree is in a state of overwintering preparation, and the leaf light and products before defoliation are transported to buds, branches, stems and roots, which are stored for winter, spring root growth, bud differentiation and new shoot growth, flowering, fruit setting and young fruit development in the coming spring and summer.

2. Pruning principles: 1. Pruning according to the standard of three-thin and three-dense (that is, the distribution of branches and leaves of the crown is thinning at the top and density at the bottom, outside and inside, and big branches and twigs), so as to improve the ventilation and light transmission conditions and improve the quality of fruit and flower buds. 2. Cut off the young autumn shoots that are too prosperous, reduce the nutrient consumption, enrich the buds, promote the continuous differentiation of flower buds and improve the fruit quality. 3. From September to November (or before defoliation after fruit harvest), base fertilizer was applied to trench and cut roots, promote root development to depth, and increase absorption area and root supply capacity (such as cytokinins, etc.). 4. In order to further improve the fruit quality, bagging, shading leaves and fruit rotation should be carried out about 20 days before fruit picking. 5. In the process of pruning, the branches, leaves and fruits of diseases and insect pests must be cut off at any time to prevent the occurrence and spread of diseases and insect pests.