Key Techniques for Introduction and Cultivation of Emerald Pear in the Old Course of the Abandoned Yellow River Region

I. Overview of the Introduction Site

Xiangshui County is located in the northeastern part of Jiangsu Province, in a warm temperate monsoon climate zone, within the floodplain of the old course of the abandoned Yellow River. The average annual temperature is 13.9°C, annual precipitation is 912mm, extreme maximum temperature is 38.7°C, extreme minimum temperature is 17°C, frost-free period is 220 days, and precipitation is mainly concentrated from May to September. The introduction demonstration orchard has sandy loam soil with deep soil layers, medium fertility, good aeration, and a pH value of 7.2. A total of 1440 Emerald Pear trees and 350 Golden Pear trees were introduced, planted in spring 2001, with a spacing of 2×3m between plants and rows, and Golden Pear used as pollinator trees in a 4:1 ratio.

II. Introduction Performance

1. Production and fruiting habits. After 6 years of observation, young trees grow vigorously with an upright posture and thick branches. Six-year-old trees naturally exceed 4m in height with an average canopy spread of 3.1m. The budbreak rate is 79%, with weak branching ability, and fruiting is mainly on short fruit branches, supplemented by long and medium fruit branches. Current-year branches generally do not easily form flower buds, but after branch bending they easily form flowers, with abundant flowers and strong productivity. Trees begin flowering in the 2nd year after planting, with average yields per mu of 530kg in the 3rd year after planting, 1260kg in the 4th year, 1960kg in the 5th year, and 2360kg in the 6th year. The fruit is oblate, with an average single fruit weight of 260g. When naturally ripe, the skin is light green, the fruit dots are small, the fruit surface is smooth, and the rate of deformed fruit is very low. The flesh is tender, juicy, with a medium-sized core, soluble solids content of 13.1%, sweet taste, very few stone cells, and superior quality.

2. Phenological period. In the Xiangshui area of Jiangsu, Emerald Pear leaf buds sprout in late March, initial flowering occurs in early April, full bloom in mid-April, fruit ripens at the end of July, and leaves fall in mid-October.

3. Adaptability. Emerald Pear has strong adaptability to high-temperature and high-humidity ecological environments, and its resistance to black spot disease, ring rot disease, and pear psylla is significantly higher than that of "Sanshui" pears. Young fruiting Emerald Pear trees are prone to fruit cracking during the fruit enlargement to ripening stage, with a maximum cracking rate of 36%, especially severe when long drought is followed by rain. As tree age increases, fruit cracking gradually decreases year by year, with a cracking rate of 7.8% in 6-year-old trees.

III. Main Cultivation Techniques

1. Planting. In winter, dig planting holes 1m long, 1m wide, and 0.8m deep. When digging, topsoil and subsoil should be piled separately. Apply 40kg of decomposed organic fertilizer per hole. When backfilling in early spring, place topsoil at the bottom and subsoil on top, backfill in layers and firm each layer. The backfilled soil should exceed the ground level by 15cm. Plant in early spring of the following year.

2. Fertilizer and water management. For 1-2 year old young trees, apply light fertilizer frequently. Apply fertilizer once after budbreak and leaf expansion, using 0.5kg of fast-acting nitrogen fertilizer urea per tree each time to promote young tree growth and rapid canopy formation. In autumn, apply 25kg of decomposed chicken manure per tree, plus 1kg of nitrogen, phosphorus, and potassium multi-element compound fertilizer. During the fruit enlargement stage, apply 1-1.5kg of multi-element compound fertilizer. At the end of September, apply 30kg of decomposed chicken manure and 1kg of multi-element compound fertilizer per tree. Irrigate promptly after fertilizing to promote timely absorption and utilization of fertilizer by the trees. If drought occurs from after budbreak to the fruit enlargement stage, irrigate promptly. During summer and autumn rainy seasons, drainage should be done promptly.

3. Training and pruning. An open-center upper layer form is adopted. Shaping mainly uses three methods: positioning, light heading, and thinning. During the young tree stage, except for heading the central leader and main branch extension branches, other branches are mostly left unpruned. Cut and thin branches as little as possible, and make full use of valuable water sprouts and back branches by bending branches to open the angle and transform and utilize them. Branch bending should be completed by the end of May. The trunk is headed at 0.8m, and 3-4 main branches are selected for the first layer. Each main branch cultivates 2-3 side branches, with the basal angle of young tree main branches reaching 70 degrees. The second layer of main branches is 1.2m from the first layer, with 2-3 main branches selected, and the basal angle reaching 60 degrees. After main branches are selected, the top is cut off to open the center. Pay attention to summer pruning. This tree form and pruning method can promote the formation of medium and short fruit branches, ensuring early fruiting and high yield.

4. Flower and fruit thinning. Emerald Pear has a high fruit-setting rate, with each inflorescence capable of setting 3-8 fruits, and some inflorescences setting as many as 11 fruits, so strict flower and fruit thinning is necessary. In early April, when flower bud scales loosen and flower buds show white, thin out weak and small flower buds, cut off the upper half of flower buds, and retain leaf buds for leaf growth to increase effective leaf area. After physiological fruit drop, thin out undersized fruits, diseased and insect-damaged fruits, and upright fruits. Keep only 1 fruit per inflorescence, with fruit spacing of 15-20cm. Six-year-old trees should retain no fewer than 160 fruits per tree. Fruit thinning should be completed by the end of April.

5. Pest and disease control. In the Xiangshui area during the dry season in May, Emerald Pear is susceptible to pear psylla, aphids, and other leaf-feeding pests such as slug moths, star caterpillars, and pear lace bugs. The main pests damaging fruits are pear fruit sawfly and peach fruit moth. The main diseases are ring rot disease, brown spot disease, and iron and zinc deficiency symptoms. Diseases can be controlled alternately with 50% Tuzet at 800 times dilution or 50% mancozeb at 600 times dilution. Pests can be controlled with imidacloprid or aphid-mite net pyrethroid pesticides, etc. Zinc and iron deficiency can be remedied by supplemental application of zinc fertilizer and ferrous sulfate.