The biological characteristics of chestnut

1 The biological characteristics of chestnut

1.1 Chestnut morphological characteristics

Chestnut is a fagaceae, deciduous tree. The bark is rough and straight, with short hair on branchlets.

1.2 Chestnut biological characteristics and ecological habits

Chestnut has strong adaptability to various types of climates, and it can grow at an average annual temperature of 8-22°C, an absolute maximum temperature of 35-39°C, an absolute minimum temperature of -25°C, and an annual rainfall of 500-1500mm. . However, in the annual average temperature of 10 ~ 14 °C, annual rainfall of 600 ~ 1400mm where the best growth. Chestnut has a higher requirement for light, and lack of light will cause its internal branchlets to senile and die, and branches rapidly move outwards, seriously affecting yield.

After the chestnut seedlings are planted, they begin to grow slowly on the ground, and the underground part grows faster, and then the on-ground part grows faster. Generally, flowering results begin in 6-7 years, and fruitfulness occurs in about 15 years. Grafting seedlings can be flowered 4 to 5 years after planting.

2 Chestnut cultivation techniques

2.1 Seed collecting

Excellent varieties are the key to achieve high-yield chestnut cultivation. In the process of achieving improved varieties, it must be adapted to local conditions and appropriately planted. The mother tree should be selected as an excellent single plant with stable yield, high yield, good quality, early fruiting, robust growth, and no pests and diseases during fruit period. When the chestnut fruit is fully ripe, the hedgehog cracks and the fruit naturally falls off. The chestnut fruit picked up from the ground is selected and immediately mixed with sand.

2.2 Nursery

Due to the low survival rate of seedlings for layering and cutting of chestnut, the two methods of seeding and grafting are generally used in production.

For chestnut hi light, the nursery should be built at an altitude of 500m, with a sunny leeward and a hilly land or riverbank with a slope of 25 or less to ensure adequate water supply and good drainage. The soil depth is up to 50cm, the groundwater level is 1m, the pH is 5.5~6.8, and the soil is fertile sandy loam or gravel loam.

Chestnut sowing time, divided into spring and autumn sowing, spring sowing is the most common. In early April, use sandy seeds for seeding, using field or seedbed ditching, spacing (15 to 20) cm (25 to 30) cm, ditch depth 5 to 10 cm, and covering soil 3 to 5 cm, placing seeds horizontally The sowing rate per acre is 125-150kg. Autumn sowing can be properly thickened, cover the grass on the surface to prevent rat damage. Nursery management is the same as general hardwood species.

Chestnut breeding uses grafting, and vegetative propagation using real or wild rootstocks has become popular as the main breeding method for chestnut trees. This anvil is the most common, but also useful for wild species, in northern China, 2 to 3 years old chestnut seedlings are used as rootstocks, and in the south most wild chestnuts belonging to the same genus are used. Scions should be grown on strong, well-developed, good-quality, and good-quality adult plants with well-grown fruiting branches or development branches, and the mid- and lower-sections of the growth leggy shoots can also be used appropriately. Branching is generally performed when the buds of the rootstock start to sprout and the bark is easily peeled off. At present, chestnut grafting generally adopts cutting, splicing, and abdominal grafting, and bud grafting is rarely applied. After that, we must do a good job in the management of windproof pillars, de-emergence, topping and weeding, strengthening fertilization, loosening of interfaces, and prevention of pests and diseases to ensure the normal growth of seedlings.

Chestnut can be planted in winter and spring. Roots were selected from 2 to 3 year old seedlings, digging large holes, planting soil, and applying basal fertilizer before planting. After planting water, the water will be immersed and cultivated into earth piles to prevent wind shaking. Afforestation density, row spacing of dry fruit forest is 6m6m; row spacing of wood and fruit is 4m5m or 2m3m; row spacing of timber forest is 2m2m or 2m3m. Chestnut is a cross-pollination species. When planting, pay attention to the configuration of pollination varieties. The main cultivars are 4-8 lines, and 1 row pollination tree is configured. If the flowering season meets the rainy weather, artificial pollination should be carried out to remedy the shortage of self-pollination.

3 Chestnut tending management technology

3.1 kinds of crops

Lilin intercropping crops can be used as farms to improve the soil structure and improve soil fertility; it can also increase food income, and grow short and grow to achieve a double harvest of chestnut grains. The intercropping crops are preferably legumes such as peanuts, mung beans, broad beans and the like. After the expansion of Chenglin’s crown, green manure plants can be grown.

3.2 Soil Management

Practice has proved that the deeper turning of Liyuan, the physical and chemical properties of the underlying soil improved significantly, the ability to retain fertilizer and water retention was strengthened, the thickness of the living soil layer was deepened, and the depth of the root distribution was thickened. After the chestnuts were harvested in all parts of Hunan, they were fully grounded and their depth was 15 to 20 cm. Yiguang and other places in Jiangsu combine the turning green in the grass season; people in the chestnut producing area in North China plan the “tree tray” under the chestnut tree, and the first time in the late autumn or early spring, the planer is 15-20cm deep and the size is equal to the size of the canopy. It is better not to be late. The second time in August between "Shoushu" and "White Dew", a depth of 12 to 16cm, cut off the fibrous roots of the topsoil, and promoted the development of the root system to deeper layers. The relevant experiments showed that the deeper turning chestnut tree root 100cm100cm soil profile observed deep chestnut tree roots than non-deep chestnut tree increased by 34, less than 2mm absorption root increased by 32.

3.3 Fertilization and Irrigation

To make the chestnut tree productive and stable, the management of fertilizer and water must be strengthened, and fertilization is usually conducted three times a year. The base fertilizer was applied in the digging garden in the clear garden in winter. The fertilizer type was mainly organic fertilizer and fertilizer was properly applied. From March to April, the second fertilizer was applied. In general, 5 to 10 kg of decomposed human and animal manure and 0.3 to 0.5 kg of urea are applied to each plant. From July to August, to promote fruit enlargement, 0.5 to 1 kg of compound fertilizer and 40 to 50 kg of organic manure were applied to each plant. The fertilizer is applied around the edge of the canopy. In the winter, the organic fertilizer is applied in a circular groove, and in the spring and summer, the chemical fertilizer is used as a top dressing. The radial application or acupoint application should be applied. The fertilizer should be promptly filled after being applied. In the dry season, conditions should be promptly irrigated.

3.4 Shaping pruning

Chestnut is a light tree species, and light has an important influence on flower bud differentiation, leaf development, fruit setting, fruit yield and quality of chestnut. Therefore, chestnut tree pruning is very important. The crown shape of the chestnut is usually semi-circular in nature, with a height of 70 to 100 cm, 5 to 6 main branches, 2 to 3 floors, and 2-3 first floors. 2 to 1 and 2 to 3, 1 to 3, and 2 to 3 side branches per main branch, 1 to 1.5 m apart, 50 cm to the main branch in the layer, 60 cm to the first side branch from the trunk, and staggered side branches to avoid Opposite. The plastic work can be completed in about 7-8 years.

After the pruning, usually "clear pruning", or only remove dense branches, branches, disease branches and dead branches, other branches are generally not trimmed.

3.5 Pest Control

The common hazards of chestnut damage include chestnut bud blight, powdery mildew, anthracnose, chestnut rust, and chestnut blight. The pests include chestnuts, weeviles, chestnuts, hornbills, and various locusts. Pest prevention and control work shall strictly implement the plant quarantine system, use selected pest resistant varieties, use pesticides safely and rationally, control the amount of pesticides, focus on biological control, and reduce environmental pollution. Taking powdery mildew and anthrax pests as an example, after the occurrence of powdery mildew, diseased branches should be cut off and burned in time, and lime sulfur and sulfur powder should be used for spraying. For pests, the main focus should be prevention, and deep plowing should be carried out in winter. Immediately extinguished, and early sowing, the chestnut seedlings were preliminarily lignified. If the insect pests were serious, insecticides could be used in an appropriate amount.

3.6 Antifreeze in tree

In the area of ​​800m above sea level, antifreeze measures are mainly applied to the whitening method of tree trunks; in the areas of 800 to 1500m above sea level, methods are mainly used to cover grass between fruit trees or to wind the trunk with straw ropes. Where conditions permit, the orchard can be treated with irrigation to maintain soil moisture, so as to improve the cold resistance of the tree and make it safe for winter.

4 Chestnut harvesting and storage

The early maturing varieties of chestnut in China are mature in about mid-August and late, and the late-maturing ones will not mature until late October or early November. Most varieties mature in October. It is necessary to wait for the chestnut to turn from blue to yellow-brown, and 30% to 40% of the chestnut have a cruciform crack at the top. The chestnut fruit is tan. At this time, the best harvest is done, otherwise the nuts are not mature and the tissue is fresh and tender. High water volume is not conducive to storage.

The method of harvesting includes two methods of picking chestnuts and picking chestnuts. The real breeding area adopts the former, and most of the producing areas use the latter. The former has the disadvantages of long work and harvesting periods, while the latter can easily damage the crown branches. Affect the results of the coming year. The harvested fruits were piled in the cumulus for several days. After most of the ball crickets were cracked, they were sorted out and stored.

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