1, the temperature of chestnut is suitable to grow in the range of annual average temperature 10- 17℃. During the growing period (April-65438+1October), the daily average temperature is 10-20℃, the winter temperature is below -25℃, and the suitable temperature for flowering is 17-27℃, below 15℃ or above 27℃. During the fruit growing period from August to September, the average temperature above 20℃ can promote the growth of nuts.
2. Castanea mollissima can be planted in the place with annual rainfall of 500-2000 mm, but the place with annual rainfall of 500- 1000 mm is the most suitable. Different phenological periods have different requirements and responses to water, especially during the filling period of chestnut in autumn. If the water is sufficient, it will be beneficial to the full growth of nuts and the increase of yield.
3. Light chestnut is a tree species with strong photophobia, and it needs sufficient light during its growing period. In the valley area where the average daily illumination time is less than 6 hours, the trees grow upright, with sparse branches and leaves, low yield and poor quality. Therefore, the selection of garden, the establishment of planting density, the way of shaping and pruning and other cultivation management should be considered according to the characteristics of chestnut's strong photophobia.
4. Castanea mollissima is suitable to grow in sandy loam with more organic matter and good ventilation, which is beneficial to the growth of roots and the production of mycorrhiza in large quantities. It does not grow well in the soil with high viscosity, poor ventilation and poor drainage (easy to accumulate water) in rainy season. Chestnut is sensitive to soil pH, the suitable pH range is 4-7, and the most suitable is slightly acidic soil of 5-6. Weathered soil in limestone mountain area is mostly alkaline, which is not suitable for developing chestnut. Granite and gneiss weathered soil is slightly acidic and breathable, which is suitable for chestnut growth. Chestnut adapts to acidic soil because it can meet the needs of chestnut trees for manganese and calcium, especially manganese. When the pH value is high, manganese is insoluble and cannot be absorbed and utilized by roots. Chestnut is a high manganese plant, and the content of manganese in leaves is above 0.2%, which obviously exceeds that of other fruit trees. However, in alkaline soil, the content of manganese in leaves will be less than 0. 12%, the color of leaves will turn green, and the metabolic function will be extremely low. Therefore, chestnut must be developed in slightly acidic soil areas.
Second, the cultivation techniques
1. There are two main propagation modes of chestnut: seedling propagation and grafting propagation. Although the method of seedling propagation is simple, low in cost and long in plant life, it can't maintain the excellent characters of varieties, and the difference between plants is great, which generally leads to late fruiting and low yield. Therefore, in recent years, the development of chestnut in various places has mostly adopted grafting propagation.
2. The selection, sowing and seedling propagation of chestnut varieties have two purposes, one is for rootstock, and the other is for direct production and planting. Seedlings used as rootstocks require robust growth, so nuts with full maturity, neat size and no insect pests and mechanical damage should be selected as seeds. Seeds directly used for the production and planting of seedlings must be collected from the mother trees with strong growth, high yield and high quality to ensure the good performance of future generations.
3. Sowing chestnut can be divided into autumn sowing and spring sowing. Autumn sowing is mostly in late autumn and early winter. The advantage of autumn sowing is that chestnut seeds need not be stored in sand, and they can be treated slightly after collection. However, due to the long-term planting of chestnut in the field in autumn, it is easily damaged by external climate, which affects the emergence rate. Spring sowing requires more than 30% seeds to germinate, or in the middle of March every year.
Sowing methods are divided into direct seeding and border seeding. Direct seeding means planting and building a garden directly according to the predetermined spacing without establishing a nursery. But the management is inconvenient and the effect is poor. At present, it is widely used in border sowing and concentrated cultivation. Nursery should be sandy loam with flat terrain, deep and fertile soil layer and good drainage. After deep ploughing, leveling and applying foot fertilizer, we made a border surface with a width of 0.8- 1m and a length of 5- 10m, and made a ditch with a row spacing of about 30cm and a depth of about 5cm on the border surface. If the soil is dry, it should be watered. After infiltration, plant with the spacing of 10- 15cm, and cover the soil with a thickness of 3-4cm. When sowing, the seeds should be laid flat in the ditch to facilitate the elongation of the primary rhizomes.
4. Seedling management: intertillage and weeding immediately after the seedlings are unearthed, which is especially important for direct seeding garden construction to ensure the growth of seedlings. After the seedlings grow 1 month, the nutrients in the seeds have been exhausted. Fertilization can be carried out twice in early June and early August, with urea application of about 5- 10 kg in 666.7 m square meters, and irrigation immediately after application. Chestnut seedlings are afraid of waterlogging. After fertilization, in addition to soil water shortage, drainage should be done in time in rainy season to avoid long-term water accumulation in nursery. It is also necessary to prevent and control pests and diseases in time to ensure that the seedlings are complete and strong.
5. The growth cycle of fertilized chestnut is divided into germination period, new shoot growth period, flowering period and fruit development period. Its fertilization is divided into base fertilizer and topdressing.
1. base fertilizer. Base fertilizer should be applied from the end of September to the beginning of 10. The base fertilizer should be organic fertilizer such as decomposed human and animal manure, soil miscellaneous fertilizer and decomposed cake fertilizer. Generally, each tree should be applied 15 ~ 20kg. Fertilization method: generally, ring ditches are dug along the periphery of the crown to fertilize. 2. Top dressing. Chasing three times a year, the first time is from the end of March to the middle of April before germination; Top-dressing the fruit fertilizer for the second time from the middle and late May to the early June; Top dressing for the third time from early July to late August can promote fruit fullness and increase yield, with 0.8 ~ 1 kg phosphorus and 0.5kg potassium nitrate applied each time. 3. Spraying fertilizer on the leaves. The first time was in the middle and late May, the second time was in the middle and late June, and the third time was in the middle and late July, and 0. 1% ~ 0.3% potassium dihydrogen phosphate was sprayed once each.
6. Skillfully prevent pests and diseases. In autumn and winter, the trunk can be coated with the mixture of the original solution of sulfur mixture, salt, quicklime, metalaxyl manganese zinc and water (1: 1: 6: 0.5: 20), which can prevent chestnut blight. First, scrape off the diseased tree. Powdery mildew can be prevented by spraying 0.3 Baume-sulfur mixture or 50% thiophanate-methyl 100 times solution at the initial stage of the disease; The control of chestnut weevil can be carried out by spraying 90% trichlorfon 1000 times solution or 800 times solution of dichlorvos in early June, and soaking nuts 10 minute in hot water at 50℃ after picking the fruit, which can kill the larvae in the fruit. The key to control chestnut borer is to scrape the overwintering bark with eggs in winter, coat the white trunk with sulfur mixture, and spray chlorpyrifos 1500 times or 1000 times in mid-May. The control of chestnut moth can be carried out by spraying 800 times mirex or 600 times isocarbophos when pests occur in July and August.