Cultivation and Management of Hawthorn Tree in Alpine area

1. Hawthorn varieties suitable for cultivation in cold regions Selecting varieties suitable for local natural conditions is the key to the success of hawthorn cultivation in cold regions. When selecting varieties, we must put cold resistance in the first place, and also pay attention to good quality. 2~3 hawthorn varieties with same or similar flowering period should be planted separately in an orchard, and fruit setting rate can be significantly increased by cross-pollination. At present, Dawang, Shuanghong and Fucha are the main hawthorn varieties suitable for cultivation in cold areas (≥10℃ annual effective accumulated temperature 2600~2700℃).

2 hawthorn seedlings propagation methods planted hawthorn trees must choose grafted seedlings. After seeding seedlings with wild hawthorn seeds, when the seedling grows to a diameter of more than 0.5 cm (5 cm from the ground), grafting is carried out by adopting tender shoots of excellent varieties from July 20 to August 20. It can also be used in the spring of the second year before and after Qingming to split or use hard bud grafting method. In order to save economic expenditure, young wild hawthorn seedlings can also be dug back and planted directly in the production garden according to row spacing in spring and autumn. The seedlings planted in spring can be grafted in July. For wild hawthorn seedlings planted before freezing in autumn, the seedlings must be cultivated with soil more than 30cm or buried in the ground soil before freezing, the cultivated soil shall be removed around Qingming in the second year, and excellent edible varieties shall be selected for hard branch grafting or tender bud grafting in July. The seedlings grafted with hard branches can bear fruit more than one year earlier than those grafted with tender shoots, and can save the cost of buying seedlings.

3. Cultivation techniques: 4 m × 4 m or 5m×4m in row spacing in fertile plain. In hilly land and hillside land, the row plant spacing is 4 m × 4 m or 4m×3m. Whether it is sunny hillside or east slope or southeast slope, it should travel north and south, which is beneficial to ventilation and light transmission among hawthorn trees.

Dig holes before seedling planting. The length, width and depth of holes in fertile soil are 50cm×50 cm × 50cm. The holes in barren soil can be enlarged to 70cm×70cm and 50~60cm deep. Before planting, we must backfill decomposed fertile soil and farm manure to ensure sufficient nutrition for seedling growth in the early stage. 1~2 years old trees must strengthen field management, do everything possible to ensure that seedlings survive. In summer, weeding and loosening should be carried out in time, and water should be replenished in time if conditions permit during drought. Before freezing, the tree body should be painted white or tied with grass or cultivated to protect the young trees so as to survive the winter safely. Hawthorn trees are rarely thinned flowers and fruits, the load per plant is large, fertilizer and water and other technical measures if lax management, will affect the normal development and growth of fruit trees. The management in the growth period mainly includes: plowing the empty space between rows every year, plowing the tree tray in 1~2 years, and plowing after spreading farm manure before plowing each time. Farm manure to poultry manure and pig manure, deer manure, plant ash, hair, poultry feathers and other best. Rational application of nitrogen fertilizer, increase the amount of phosphorus and potassium fertilizer in later stage, trees over 10 years old, urea 250g per plant in early May, to supplement the nutrients needed for tree growth, flowering and fruiting. In the middle of July, 400~500g of nitrogen, phosphorus and potassium fertilizer were applied to each plant according to the ratio of 2:4:4 to promote fruit expansion and improve fruit quality. Fertilizer should be divided into dozens of holes (pits), the hole (pit) depth is not less than 15cm. The distance between the fertilizer hole (pit) and the tree is 80~100cm. After fertilization, soil is covered. If conditions permit, water immediately to accelerate the dissolution of fertilizer and promote the root system to absorb fertilizer as soon as possible. In summer, useless branches and dead branches should be cut off at any time. For some lateral branches that are not open enough, be sure to pull them with ropes or support them with sticks to make them reach the required angle.

4 pest control hawthorn tree pests are mainly leaf mites and peach fruit borer. Tetranychus mites mainly harm buds, tender leaves and flower buds. Select targeted pesticides during the occurrence period and use them according to the instructions. Peach fruit borer can make fruit lose edible value, resulting in significant yield reduction. The occurrence time of fruit borer is related to temperature and moisture at that time. The occurrence time and pest control time can refer to the occurrence rule of fruit borer on apple tree and pear tree, and can be controlled by using peaches, phoxim, dichlorvos and other pesticides.

5 plastic pruning Hawthorn tree plastic pruning basically comprehensive use of pear trees, apple trees and plum trees, peach trees the best part of the plastic pruning technology. When adopting the scattered layered shape, it is roughly the same as the shaping and pruning method of apple tree and pear tree; when adopting the natural round head shape or natural open heart shape of multiple main branches, it is basically the same as the shaping and pruning method of plum tree and peach tree. Hawthorn tree dry weaker, easy to tilt the center dry, partial dry, or partial crown. Once the central trunk of trees more than 10 years old is weak or slightly dry, the extension branches of the central trunk should be replaced. When the central trunk is seriously deviated and difficult to cultivate, it should follow its natural growth, remove the central trunk, change to a natural open heart shape, and leave 3~4 main branches in the whole tree. At this time, the tree shape is completely the same as the shaping and pruning method of peach and plum trees. Hawthorn tree pruning improper, easy to cause the fruit position shift. In order to stabilize yield and maintain good tree shape, when pruning, the bearing mother branches should be retracted in turn. Rejuvenate those fruiting for many years and drooping branches, should be in 3~5 years old branches on the more retractive. During the year, more mother branches should be thinned to keep the ratio of fruiting mother branches to developing branches at the lowest point of 1:1(or 2:1), and at the same time, multiple pruning should be carried out at the bud stage to thin out flower buds on some weaker branches. Crown closed seriously to sparse or withdraw some large branches, cut off some of the development of branches, so that the whole tree ventilation and light transmission.