Key techniques of open field cultivation of big cherry

In recent years, the planting scope and production scale of big cherry have been continuously expanded, forming the production areas around Bohai Bay, the old route of the Yellow River, the low altitude of the Loess Plateau, the southwest highlands and the edge of the desert, covering more than 20 provinces in China. Shandong, Dalian and Qinhuangdao in the Bohai Bay area are the dominant producing areas.

The ability of big cherry cultivated in open field to resist disastrous weather is poor, and the cultivation technique is of great significance to improve the benefit.

I. Garden site selection

Big cherry is vulnerable to low temperature, drought and flood, strong wind, hail and other disasters. When building the garden, we should choose the land with high terrain, low groundwater level and not easy to accumulate water, and we can establish windbreak forest according to the need. At the same time, sandy loam or loam with deep soil layer, good air permeability and neutral to slightly acidic soil (pH 6.5-7.5) should be selected, and should not be stubble with peach trees. Deep soil ploughing must be carried out before planting in order to increase soil permeability and organic matter content and reduce soil bulk density. The soil with loose soil and high organic matter content has strong buffering capacity to Rain Water, which is more suitable for the cultivation of big cherry.

II. Selection of rootstocks and varieties

At present, big cherry rootstocks mainly include Daqingye, Gisela series, Mahari, Cuote and so on, which have their own characteristics and are different in drought resistance, waterlogging resistance, disease resistance and so on. Therefore, according to the actual situation to choose the corresponding rootstocks, such as Gisela No. 5 dwarfing effect, Mahari anti-root cancer.

According to the mature period, big cherry can be divided into early-maturing varieties (fruit development period 30-40 days), middle-ripening varieties (fruit development period 40-50 days) and late-ripening varieties (fruit development period more than 50 days). Early-maturing varieties include red lantern, yellow honey, Italian early red and so on. Pioneer and Na Weng are late-maturing varieties. The fine varieties of the corresponding mature period should be selected according to the local climatic conditions. In recent years, China has introduced some self-fruiting varieties, such as Stella, Rabins, Yanhong, Xinxing, etc., with good yield and quality, which is worth popularizing in production.

Third, shaping and pruning

The traditional big cherry tree shape is usually happy. In recent years, dry cultivation has been widely used in newly-built orchards. Spindle is a practical tree shape with early fruit and high yield in close planting cultivation. The planting density is determined according to site conditions, varieties, shaping methods and management level, and the row spacing is 2 × 5 m × 3 × 6 m. For the varieties with compact tree shape and high yield, such as sand honey bean, Zaoshengfan, Sparkry, Pioneer, etc., the plant row spacing can be 2 × 2.5 m × 4 m; for the varieties with strong growth, such as red lamp, Meizao, Samitt, etc., the plant spacing of 3 m × 4 m can be adopted.

After the big cherry is planted, the general varieties can begin to bear fruit after 3 years. Pruning in the growing season mainly used sprouting, coring, twisting and thinning, etc., coring and twisting were carried out on the branches of the same year from May to June, and overdense branches were thinned from July to August. Winter pruning is mainly to adjust the tree shape properly and update the fruiting branch group.

4. Pollination

Big cherry starts from flower bud germination, goes through the process of flowering, leaf spreading, shoot tapping, fruit development, flower bud differentiation, deciduous leaves, dormancy and so on. The fruit development period (from flowering to fruit ripening) is 30-60 days, and the cherry cultivated in open field begins to mature in late May.

Most big cherry varieties do not bear fruit or have low seed setting rate, so suitable pollination trees must be arranged in production, and the suitable cultivation ratio of main varieties and pollinated varieties is 3 ∶ 1 or 2 ∶ 1. The pollinated varieties had better choose the varieties with good fruit economic characters, large amount of pollen and basically consistent with the flowering period of the main varieties. It is found that Pioneer, Rabins, Steinler and Rainey are ideal pollination varieties.

Fifth, frost prevention during flowering

Big cherry is a kind of fruit tree which likes temperature and is not tolerant to cold. Open field cultivation requires an annual average temperature of 7 ℃ ~ 14 ℃. When it is higher than 15 ℃, it will blossom more and set fruit less. Low temperature, overcast and rain during flowering will lead to poor pollination and fertilization and reduce production. The critical temperature of freezing injury in the bud stage of big cherry is 1 ℃ ~ 2 ℃, and all buds under-3 ℃ will be frozen for more than 4 hours. Orchard smoking is an effective measure to prevent frost in spring, and the key of this method is to make smoke cover the orchard.

VI. Fertilizer and water management

After the big cherry entered the high-yield period, the level of fertilizer and water management not only affected the yield of big cherry in the same year, but also affected the production in the next year. It is necessary to master the type, quantity and period of fertilizer according to tree age, tree potential, soil fertility and fertilizer demand characteristics of varieties. Attention should be paid to several critical periods in fertilization. One is to apply base fertilizer in autumn, mainly organic fertilizer from September to November, with 2000-3000 kg per mu, supplemented with appropriate amount of nitrogen, phosphorus, potassium or micro-fertilizer. Second, topdressing before flowering, mainly nitrogen fertilizer, 1.5 kg urea per fruiting tree to promote germination and flowering. Generally speaking, topdressing should not be carried out during the hard-core development period, so as not to affect the fruit quality. The third is topdressing after fruit harvest. About 10 days after harvest, a large number of flower buds differentiate, and quick-acting compound fertilizer should be applied, mainly phosphorus and potassium fertilizer, 0.4-0.6 kg per plant, so as to increase nutrition accumulation and promote flower bud differentiation.

Watering big cherries can be carried out in the following key periods. Pre-anthesis water: from germination to flowering, it meets the water demand of leaf expansion and flowering, and is conducive to the formation of flower buds. Fruit-promoting water: after flowering to before fruit ripening. At this time, the tree grows vigorously, is the most sensitive to water supply, and can be watered for 2 or 3 times. Postharvest water: after fruit picking. At this time, the differentiation of flower buds is concentrated, and it is appropriate to wet the land with water. Frozen water: after applying base fertilizer in autumn, it should be poured thoroughly. During the period from the fruit whitening to the beginning of coloring, flood irrigation is strictly prohibited to prevent fruit cracking.