Chestnuts are distributed in Liaoning, Beijing, Hebei, Shandong, Henan and other places in China. They are big, spherical, with thorns outside, and there are 2-3 nuts in the shell bucket. The famous variety is Liangxiang chestnut, which is produced in Fangshan Liangxiang, a suburb of Beijing. The fruit is small, about 5 grams, sweet and ripe in the middle of 10. Qianxi Li Ming, also known as "red skin" and "red hair", is produced in Qianxi, Xinglong and Guo Da, Hebei Province, weighing 7-9.5 grams, with red and brown skin, fresh and sweet taste and maturing in mid-September. Hong Guang chestnut in Laiyang, produced in Zhuangtou, Laiyang, Shandong Province, has large fruit, dark brown skin, bright color, good quality and sweet taste, and matures in early September; In addition, Castanea henryi, also known as Pearl Chestnut, is distributed in the Yangtze River valley and all parts of the south of the Yangtze River. The shell contains an oval nut, which tastes like chestnut. Castanea mollissima is the general name of trees or shrubs of Castanea in Beech family, with about 7-9 species, which are native to temperate regions in the northern hemisphere. Most species of chestnut are deciduous trees, with a height of 20-40 meters, and only a few are shrubs. All kinds of chestnut bear edible nuts, with simple leaves, oval or oblong shape, length 10-30 cm, width 4- 10 cm, and bristles on the edges. Monoecious, the male flowers are erect catkins, and the female flowers are single or several in the involucre. Nuts are enclosed in involucre, with dense spikes. The diameter of involucre is 5- 1 1 cm, and there are 1-7 nuts in one involucre. Chestnut was once the main tree species in the eastern United States, but it was almost extinct after being infected by a fungal disease, and chestnut trees in Europe and West Asia were also susceptible to infection. However, chestnut trees from China and Japan are resistant to this fungus, so they are now introduced to the United States to cultivate hybrid trees that can resist the fungus. Chestnut is one of the earliest cultivated fruit trees in China, with a cultivation history of about 2000 ~ 3000 years. The leaves are lanceolate or oblong, and the leaf margin is serrated. Flowers unisexual, monoecious; Male flowers are inflorescences. When it matures, the involucre splits and the chestnuts fall off. Nuts are purple-brown, yellow-brown or nearly smooth, and the flesh is yellow. Chestnut varieties in China contain sugar, starch, protein, fat, vitamins and minerals, which can be generally divided into two categories: northern chestnut and southern chestnut. Chestnut in North China has small nuts and waxy flesh, which is suitable for frying. The famous varieties are Ming chestnut, pointed chestnut and Ming chestnut. Chestnut in South China has large nuts and japonica pulp, which is suitable for vegetable use. There are nine varieties, such as Li Kui, Chestnut with shallow thorns and so on. This tree is very strong. The root system is developed with mycorrhiza. Drought-resistant and barren, suitable for mountain cultivation. Suitable for acidic soil. Multi-row sowing can also be grafted and propagated. Wood is dense, hard and moisture-proof. Branches, barks and involucres contain tannins, and tannin extracts can be extracted. Cultivation history Chestnut has a long history. Sima Qian in the Western Han Dynasty clearly recorded that "Yan, Qin and Li ... are all waiting with thousands of families in Qian Qian." In Historical Records and Biography of Huo Zhi. In the Biography of Su Qin, there is a saying that "Qin said to wait for Japan: the south has the favor of Jieshi Yanmen, and the north has the benefit of jujube and chestnut. Although the people don't work hard, they are full of dates and chestnuts, which is called abundance. " Lu Ji also commented on the Book of Songs in the Western Jin Dynasty: "All five parties have chestnuts, but those born by Yuyang and Fanyang are sweet and delicious, and the place is not as good as that." It can be seen that the working people in China have planted chestnuts as early as 4000 years ago. Castanea mollissima is mostly born in low mountains and gentle slopes and floodplains. Hebei (Qianxi-Chestnut Production Base, Kuancheng Manchu Autonomous County-Chestnut Production Base, Qinglong Funing-Chestnut Production Base), Shandong, Hubei (Luotian Macheng), Xinyang Luoshan and Zhenan in southern Shaanxi are famous chestnut producing areas. Growth characteristics like light, and insufficient light causes branches to die or bear no fruit. Not strict with the soil, like fertile, moist, well-drained sandy or callose loam, and have strong resistance to harmful gases. Avoid stagnant water and sticky soil. Deep roots, developed roots, strong germination, pruning resistance and many pests. In addition, its varieties are cold-resistant and drought-tolerant. The service life is over 300 years. Castanea mollissima has a wide crown and large branches and leaves, so it is suitable for planting alone or in groups on lawns and slopes in parks. It can also be used as tree species for afforestation and soil and water conservation in mountainous areas. At present, it mainly produces and grows dried fruits. Chestnut has been cultivated in China for more than 2000 years, and there are many varieties in various places, so we should pay attention to choosing local excellent varieties when breeding. Chestnut has strong adaptability, convenient cultivation and management, stable yield and is deeply loved by the masses. People in North China call chestnut a "hardcore crop", which is a good tree species combining greening and production. The planting techniques and growth characteristics of chestnut have wide adaptability to climate and soil conditions. The suitable annual average temperature is 65438 0.5—265438 0.8℃. Excessive temperature will lead to insufficient hibernation, poor growth and development, and low temperature will easily lead to frostbite. Chestnut likes moist soil, but it is afraid of rain and waterlogging. If there is too much rainfall, the soil will accumulate water for a long time, which will easily affect the growth of roots, especially mycorrhiza. Therefore, it is not suitable to develop chestnut orchards in low-lying and waterlogged areas. Chestnut is sensitive to soil PH value, and is suitable for growing in slightly acidic soil with pH value of 5-6. This is because chestnut is a high manganese plant, which can activate nutrients such as manganese and calcium under acidic conditions, which is beneficial to the absorption and utilization of chestnut. Xuzhou is located in the southern edge of Huangtan, with an annual average temperature of13.7-14.1℃ and an annual precipitation of 782-946 mm, which is suitable for the growth and development of millet trees. Cultivation and management techniques (1) Selection of chestnut orchard: The chestnut orchard should be sandy loam with low groundwater level and good drainage. Avoid planting in places with saline-alkali soil, low humidity and strong wind. In order to open up millet orchards in hilly areas, we should choose areas near mountains with gentle terrain and thick soil layers, and then gradually expand to areas with poor conditions. (2) Variety selection: the local excellent varieties are mainly selected, such as Paoche No.2, Chen Guo 1, etc., and Shi Feng, Jinfeng, Haifeng, Qingmao Soft Spine, Chushuhong and other varieties are introduced appropriately. According to different edible requirements, fried chestnut varieties should be given priority to, and excellent chestnut varieties should be developed appropriately, taking into account foreign trade export and domestic market demand. At the same time, early, middle and late varieties should be reasonably matched. (3) Rational allocation of pollination trees: Chestnut trees mainly spread pollen by wind, but because chestnut trees are dioecious and self-pollinated, a single variety often produces empty buds due to poor pollination. Therefore, new chestnut orchards must be equipped with 10% pollination trees. Practice has proved that it is better to use Chushuhong as pollination tree in Xinyang City. (4) Reasonable close planting: Reasonable close planting is the basic measure to improve the yield per unit area. It is advisable to use 30-40 plants per mu in plain chestnut orchards and 40-60 plants per mu in mountain chestnut orchards. It is planned to plant 60-11plant per mu in close planting chestnut orchard, and then gradually carry out alternate thinning. (5) Rational fertilization: Rational fertilization is an important basis for high yield of chestnut garden. The base fertilizer should be mainly soil mixed fertilizer, so as to improve the soil, improve the soil's ability to retain fertilizer and water, and provide more comprehensive nutrient elements. The best application time is autumn after fruit picking, during which the temperature is high and the fertilizer is easy to decompose; At the same time, it is in the new root stage, which is beneficial to absorption, thus promoting the accumulation of nutrients in the tree and playing a good role in the differentiation of female flowers in the coming year. Topdressing is mainly available nitrogen fertilizer, combined with phosphorus and potassium fertilizer, and the topdressing time is early spring and summer. Generally, topdressing is 0.3-0.5 kg urea per plant of newly planted fruit trees in spring, and 2 kg urea per plant in full fruit stage. After topdressing, water should be combined to give full play to fertilizer efficiency. Topdressing in summer is carried out from late July to mid-August. At this time, the application of available nitrogen fertilizer and phosphorus fertilizer can promote the increase of fruit grain number, full pulp and improve fruit quality. Top dressing outside the roots can be carried out many times a year, and the key points should be done twice. Spraying 0.3%-0.5% urea and 0.3%-0.5% borax for the first time in early spring when the basal leaves of branches turn from yellow to green, promotes the function of basal leaves, improves photosynthesis and promotes the formation of potted flowers. The second time is to spray 0. 1% potassium dihydrogen phosphate twice at intervals between1month and half a month before harvest, which is mainly used to improve photosynthetic efficiency and promote the transfer of nutrients such as leaves to fruits, and has a significant effect on increasing single grain weight. (6) Irrigation: Castanea mollissima likes water. Generally, watering once before germination and once during the rapid growth period of fruit is beneficial to the normal growth and development of fruit trees and the improvement of fruit quality. (7) Plastic pruning: Pruning chestnut trees can be divided into winter pruning and summer pruning. Winter pruning from defoliation to germination in the following spring can promote the growth of millet trees and the formation of female flowers. The main methods are cutting short, thinning branches, retracting, slow releasing, pulling branches and carving. Summer pruning mainly refers to germination, pit removal, emasculation and branch thinning in the growing season, and its function is to promote branching, increase female flowers, and improve seed setting rate and single grain weight. 1. Shortcut: Cut off part of annual branches. Short cutting can promote branching, enhance tree vigor, compact crown, reduce male flowers and adjust nutrient distribution. The leafy trees can be pruned in a delayed way, and they can be cut short after germination. 2. Retraction: it is a short cut of perennial branches. It is mostly used for perennial branches with weak growth, outward displacement of fruit and serious exposure in holes. 3. Drainage: that is, the coarse branches, light blocking branches and slender branches in the cavity are drained from the base. 4. Hat shears: cut short near the new sharp wheel mark in winter, and the coring time is different. Leave 2-4 small buds on the ring mark of the new tip, which is called movable cap pruning. If handled properly, only the small buds on the cap and the big buds under the ring mark can produce fruiting branches. Leaving no short buds on the ring mark of the new tip is called wearing a dead hat to prune, so that the big buds under the ring mark produce fruiting branches. Under normal circumstances, the weak branches wear dead hat scissors, and the strong branches wear live hat scissors. 5. Sustained release: Sustained release is irrelevant. Its main function is to disperse nutrition and relieve tree vigor. Slow-release pruning is often used for lush trees. 6. Branching and scribing: For the strong and vigorous auxiliary branches whose crown is not pitted, flatten them when the juice flows to the bud in spring, and scribble above the bud that needs to germinate, so as to make them grow strong and vigorous branches. When pruning in winter, the slowly released and leveled branches are retracted to the part where the strong branches are drawn. 7. Coring: When the new tip grows to 30 cm, remove the top of the new tip. Mainly used for flourishing branches, the purpose is to promote early fruiting of branches. Pick your heart 2-3 times a year. The new buds of the first fruit-bearing trees are long and lush. When the front branches of the fruit grow out, 3-5 buds are left for picking. After the top of the fruit is pitted, about three thick branches can be formed, which increases the proportion of fruiting branches and slows down the outward migration of fruiting parts. 8. castration: only a few male inflorescences are left on the branches, and the rest are gone. Its main function is to control nutrition, promote the formation of female flowers and improve the strength of fruiting. (8) Flower thinning and fruit pollination: In flower thinning, young flowers and inferior flowers can be directly removed by hand, and Mr. Wang's big flowers and good flowers should be kept as much as possible. Generally, it is advisable to leave 1-3 female flowers per fruiting branch. It is best to use fruit thinning scissors and leave 1 single bract on each node. When thinning flowers and fruits, we should master the principle of leaving more outside the crown and less inside. Artificial pollination should choose varieties with good quality, large grain, early heating period and easy peeling as pollination trees. When the anthers of the male inflorescence on a branch or most flower clusters in the male inflorescence just change from green to yellow, spread the collected male inflorescence on glass or clean white paper before 5 am, put it in a dry and windless place, turn it twice a day, and put the fallen pollen and anthers into a clean brown bottle for later use. When the polymorphic stigma of three female flowers in an involucre completely extends to the inverted yellow stone, dip the pollen on the inverted stigma with a brush or pencil with a rubber head. If the height of the tree is not convenient for dipping, it can be made by shaking gauze bags or spraying powder according to the ratio of pollen 1 serving and sweet potato powder filler of 5 parts. (9) Harvest and storage: 1. Harvest: There are two ways to harvest chestnuts: picking chestnuts and threshing millet. The method of picking chestnuts is to pick chestnuts manually after the chestnuts are fully heated and naturally fall to the ground. In order to pick chestnuts easily, weeds on the ground should be removed before chestnut buds break out. When harvesting, shake the tree first, and then pick up all the fallen chestnuts. Be sure to pick it up every morning and evening. The advantages of chestnut picking method are full chestnut, high yield, good quality and strong storage resistance. The chestnut beating method is to knock down the mature chestnut bracts in batches with bamboo poles, and then pick up the chestnut bracts and chestnuts. Harvesting in this way is usually carried out every 2-3 days. When the buds are opened, tap the twigs inward from the periphery of the crown to shake off the chestnut buds so as not to damage the branches and leaves. It is forbidden to lay all chestnut buds with different maturity at one time. The harvested chestnuts should be treated as soon as possible, because the temperature is high, the water content of chestnuts is high, the breathing intensity is high, and a lot of heat is generated. Chestnuts are easily moldy if they are not treated in time. The treatment method is to choose a cool and ventilated place, spread a thin layer of chestnut bracts with a thickness of 20-30 cm, water them every day, cool down and sweat for 2-3 days, and then thresh them manually.