The main purpose of pear protected cultivation is to make pear fruits mature ahead of time and go on the market early, thus prolonging the supply period of fresh fruits. Therefore, when selecting varieties, we should choose the early-maturing varieties that are most suitable for the local ecological environment, such as July Crisp, Zaosheng Fengshui, Changshou, Cuiguan, Zaomeisu, Zhongli 1, etc. At the same time, because pear protected cultivation is to complete its growth and life cycle in a closed and limited space, we should choose varieties with relatively weak growth potential, short internodes, compact crown and early fruit, such as dwarf sweet water, Xishui, Golden Pear, New Century and Golden Twentieth Century. In addition, in order to enrich the market of early-maturing pears, we can also adopt excellent medium-maturing pear varieties with large fruit shape, such as Huang Guan and Xizilv.

(2) Reasonable close planting

Protected cultivation is a highly intensive and efficient agricultural production, so it is necessary to make full use of land resources and light energy resources. Most pear varieties have high germination rate and low branching ability. Within 1 ~ 2 years after planting, the amount of branches is small and the crown formation is slow. Reasonable close planting can improve the yield and benefit per unit area in the early stage, and achieve the goals of early fruiting, early high yield and early income increase; At the same time, we should also consider the continuous high yield in the full fruit period, which is conducive to ventilation and light transmission. Usually, the plant spacing of 1 m× 2 m, 1 m× 3 m or 1.5 m× 3 m is adopted in production, depending on the variety characteristics and modeling methods. If there is canopy phenomenon in the later stage, it can be drained or drained to maintain good lighting conditions in the shed.

(3) Configuration of pollination trees

Protected cultivation is in a closed environment, without exotic pollen. Most pear varieties have low or no self-pollination rate, or even no pollen at all. In order to ensure the normal fruit of pear trees, pollination trees must be strictly configured. Pollination varieties should meet the flowering period of the main varieties or 1 ~ 2 days in advance, with large pollen quantity and good affinity. The number of pollinated varieties planted depends on their excellent conditions. If the pollinated varieties are also excellent varieties, the ratio of pollinated varieties to main cultivated varieties can be 1: 1, and if the pollinated varieties are common varieties, 1: 4 or 1: 5 can be used. In order to facilitate management, the two varieties can be planted in proportion.

(4) The chilling requirement of pear trees

Promoting the early germination of pear trees is the main factor leading to the early maturity of protected cultivation fruits. Generally speaking, the earlier the cultivation measures such as plastic film mulching and greenhouse heating are carried out, the earlier the fruit ripens. However, this progress is not infinite. If it exceeds a certain limit, even if it is heated, the flowering period is not obvious in advance, and it is often difficult to obtain normal yield. Pear trees must undergo natural dormancy in winter to meet the low temperature accumulation required for dormancy, that is, cold energy is needed to germinate, blossom and bear fruit normally. Under the condition of protected cultivation, it is possible to break dormancy and promote growth by heating only after the cooling capacity required by trees is met. Therefore, we must choose varieties with low cooling capacity. It is best to know the cold requirement of varieties in order to provide theoretical basis for the determination of film mulching time.

(5) Adjustment of the environment in the facility

Including temperature, light, humidity, moisture, carbon dioxide concentration, etc., must meet the biological characteristics of pear trees and the requirements of environmental conditions in each growth and development period. Low temperature in germination facilities may affect the germination process, while high temperature also has obvious side effects. The temperature of flowering period (including day and night) is related to the development of flower organs, pollen germination, pollination, fertilization and early physiological fruit drop of fruit trees. If the regulation is not good, it will not only affect the yield of the current year, but also affect the normal growth and development of pear trees in the next year. Due to the influence of covering materials, the light in the facility is lower than that outside. In this sense, under the condition of insufficient light, protected cultivation leads to less assimilated nutrition delivered to fruits and other parts, which easily leads to insufficient growth of branches and leaves, less flowers, more physiological fruit drop, color difference of fruits and low sugar content. In protected cultivation, because the rain is blocked by the plastic film, sometimes the air humidity will drop and become a local dry state. For example, excessive evaporation of water in the bud during germination will cause physiological damage to the bud.