What are the key points for autumn management of ginkgo trees?

Ginkgo (Ginkgo biloba L.) is a deciduous tree of the Ginkgoaceae family and the genus Ginkgo. Ginkgo appeared hundreds of millions of years ago and is the oldest relict plant among the gymnosperms left over after the Quaternary glaciation. The ginkgo trees still alive today are rare and scattered, and old trees over a hundred years old are no longer commonly seen. All other plants in the same class as it have already gone extinct, so ginkgo also enjoys the reputation of a living fossil. Its varieties and cultivars include: yellow-leaf ginkgo, columnar ginkgo, split-leaf ginkgo, weeping ginkgo, variegated-leaf ginkgo and 26 others in total.

Growth habits of ginkgo

Ginkgo is a rare tree species relict from the Mesozoic era and is native to China. Only Zhejiang Tianmu Mountain has trees in a wild state, growing in natural forests at an altitude of 500-1000 m on acidic (pH 5~5.5) yellow soil in well-drained areas, often mixed with coniferous and broadleaf species such as Japanese cedar, Torreya grandis and tupelo, and growing vigorously.

Ginkgo is a sun-loving tree that prefers appropriately moist but well-drained deep loam, and is suited to growing in subtropical monsoon regions with relatively favorable hydrothermal conditions. It can grow well in both acidic soil (pH 4.5) and calcareous soil (pH 8.0), but neutral or slightly acidic soil is most suitable. It does not tolerate waterlogged sites and is relatively drought-tolerant, though it grows poorly only in overly dry places, on rocky hillsides or in low-lying wet areas. Early growth is relatively slow, and its ability to sprout from the base is strong. Female plants generally begin to bear fruit after about 20 years, and 500-year-old large trees can still bear fruit normally. Generally, buds swell and leaves unfold from late March to early April, flowering occurs from early to mid-April, seeds mature from late September to early October, and leaves fall from late October to November.

Key points for autumn management of ginkgo trees

Autumn is the nutrient storage period for ginkgo trees. The key to autumn management of ginkgo trees is to maintain the assimilative function of the leaves, prevent early leaf fall, improve the cold resistance of ginkgo trees, promote root growth, and accelerate flower bud differentiation. 1. Soil, fertilizer and water management. Apply base fertilizer in autumn. Carry out around the Autumn Equinox. In production, fertilize according to the tree, that is, determine the amount of fertilizer based on tree age, tree vigor, amount of fruit borne, soil conditions, etc., but generally apply 1-2 kg of fertilizer per 1 kg of fruit, mainly decomposed organic fertilizer; the fertilization depth is generally 40-60 cm; use semi-ring-shaped trenches or radial trenches, and alternately open trenches around the outer edge of the canopy for fertilization. Foliar spraying. For ginkgo trees that are weaker in growth or have entered the full fruiting stage, start after fruit harvest and spray once a month with 0.2-0.4% urea and 0.3% potassium dihydrogen phosphate. Irrigation and drainage. Autumn is the late stage of vegetative growth. Reasonable irrigation is conducive to the production and accumulation of nutrients and to the formation of flower buds. At the same time, attention should also be paid to drainage to prevent ginkgo trees from becoming diseased due to waterlogging. Deep plowing and expanding the tree. Autumn plowing is carried out from August to November, before the soil freezes, to a depth of about 20 cm. Deep turning can be done for individual trees by digging a ring-shaped trench in the ground vertically below the edge of the canopy, or by digging strip trenches between rows to a depth of about 60 cm. When expanding the tree, do not cut thick roots, and pile topsoil and subsoil separately. When backfilling, mix the topsoil with rotten leaves, weeds, dry stalks or other farmyard manure and place it in the lower half of the trench, and put the original subsoil in the upper half of the trench. The tree can be expanded according to the spread of the ginkgo tree's root system. 2. Training and pruning. After ginkgo trees are harvested, bend and spread the angle of vigorous branches to moderate tree vigor and promote flower formation; pinch the new shoots twice to promote branching and cultivate branch groups; appropriately retract fruiting branches that have become significantly weak and drooping after fruiting; for vigorous water sprouts sprouting inside the canopy, take measures such as pinching and twisting shoots to control their vegetative growth; for water sprouts with no space to grow, remove them promptly. For orchards with excessively vigorous growth, spray paclobutrazol or the growth regulator PBO to control tree vigor so as to facilitate the formation of more flower buds. 3. Pest and disease control. After fruit harvest, ginkgo trees are often harmed by pests and diseases. Spray pesticides in a timely manner according to the actual situation to protect the leaves and increase nutrient accumulation in the tree. Fenvalerate 100-fold solution can be sprayed to control aphids; 40% dicofol emulsifiable concentrate 1500-2000-fold solution or 1000-fold pyridaben spray can be used to control red spiders. Spray fenpropathrin 800-1000-fold solution or fenpropathrin to control tent caterpillars and puss caterpillars.