"Fertilizer is applied in four seasons, and autumn is the most important." Fruit trees consume a lot of nutrients after germination, branching, flowering and fruiting in a year. Before fruit picking, base fertilizer should be applied in autumn in time, which plays an important role in tree recovery, overwintering and cold protection, flower bud differentiation and high quality and high yield in the second year.

1. The nutrients consumed by fruit trees during the period from germination in early spring to flowering and fruit setting are mainly the nutrients stored in the tree in the previous year. The best period for storing nutrients is the period from fruit harvest to defoliation. Applying base fertilizer in autumn can add nutrients to the tree.

2. In winter and spring, the temperature is low and the decomposition of inorganic fertilizer is slow. During this period, the application of inorganic fertilizer can not give full play to the fertilizer. After the organic fertilizer exerts its effect, it often forms the growth of new shoots of fruit trees, which has an adverse impact on the flower bud differentiation and fruit setting rate of fruit trees. Spring is in the period of nutrient accumulation of fruit trees, the aboveground part basically stops growing, and the leaf photosynthesis is still vigorous, which is conducive to transporting more nutrients to branches and stems.

3. Applying base fertilizer in autumn can make the soil loose, which is conducive to conserving moisture in orchards, preventing drought in winter and spring, increasing ground temperature and avoiding freezing damage to the roots of fruit trees.

4. Autumn is the peak period of root growth in a year. It has vigorous life activities and strong ability to absorb nutrients, which is conducive to delaying leaf aging, strengthening autumn leaf light cooperation industry and adding tree nutrient reserves.

5. In autumn, the soil temperature is high and the moisture content is good, which is conducive to the activities of soil microorganisms. The applied inorganic fertilizer decays quickly and is easy to be absorbed by the root system. In addition, organic fertilizer forms humus under the action of microorganisms, improves the content of soil inorganic matter, improves the aggregate structure of soil, improves soil permeability and the ability of fertilizer and water conservation, ensures the normal growth and development of fruit trees, promotes the high and stable yield of fruit trees and obtains economic benefits as soon as possible.

6. The application of base fertilizer in autumn is conducive to coordinate nutrient growth and reproductive growth. After the quick-acting nutrients in the fertilizer are absorbed, it can enhance the function of leaves, increase nutrient accumulation, promote the plumpness of flower buds, sprout early in the next spring, bloom neatly, grow strong spring shoots and grow in large quantities, which is conducive to maintaining strong and healthy tree vigor; Nutrients are easily absorbed and applied in spring after long-term decomposition in the soil, which enhances the early development of spring shoots and provides preparation for flower bud differentiation.

7. Improve the root growth environment and improve the stress resistance function of trees. Combined with autumn fertilization and deep ploughing of soil, it can optimize soil structure, improve soil permeability conditions, be conducive to root respiration, further strengthen the function of water and fertilizer conservation, and improve the ability of freezing and cold resistance.

8. Autumn is the vigorous period of root growth of fruit trees. The coarse roots injured by fertilization can heal quickly and promote new roots quickly, so as to add the number of absorbing roots, expand the absorption area of nutrient elements and greatly improve the utilization rate of fertilizer.