2. Planting method: the taproot of walnut seedlings is very long, and the pit depth and width are 0.8- 1 m respectively. First, fill the topsoil and base fertilizer at the bottom of the pit, about 20 cm away from the pit surface. When planting, use scissors to cut off the seedlings with soaked roots and fully absorbed water, put them in the into the pit vertically, spread the roots around, then fill them until they are flush with the ground, then fill them with water and seal them.
Second, plastic trimming:
It is an important cultivation technique to make walnut bear fruit early, high and stable yield and reasonable shaping and pruning. The pruning period of walnut is different from that of ordinary fruit trees. This is done after the fruit is picked and before the leaves turn yellow. In North China, it is best to prune between "white dew" and "cold dew". Pruning at this time, although the temperature is low, the wound heals slowly, but the nutrient loss is less. Young trees can be pruned early because they have no fruit, and they can start from the "Summer Festival". Spring pruning is generally carried out around the "long summer". It's too late, because the branches and leaves are too big and consume too many nutrients, which is not conducive to the growth of trees.
1, young tree pruning: mainly to cultivate tree skeleton, lay a good foundation, quickly expand crown, and promote early fruiting and high yield. The tree shape of walnut is generally sparse and scattered, natural and happy.
(1) Sparse layer dispersion: the central dominant tree is obvious, and 5-7 main branches are divided into 2-3 layers, so that there are many branches in the tree, the crown is large and the yield is high. The key points of plastic surgery are: setting the height of trunk 1.5-2.5 meters, poor soil conditions, keeping trunk low, and rationally allocating the position and direction of main branches. The main branch spacing1-1.5m should not be too close. The first of the three main branches of the base is about 1.5m away from the main branch. If it is too close, it will form a door side, and the branch spacing around the crown should be reduced. Attention should be paid to maintaining the growth advantages of major central branches. Under normal circumstances, you can't change your head easily, which is an important feature different from other fruit tree pruning.
(2) Natural joy: the central main stem is not obvious, with 2-3 main branches, showing a 2-fork or 3-fork structure. In order to accelerate the crown expansion of young walnut trees, increase the number of branches, realize fruit setting and early high yield, summer pruning and autumn pruning can be used to promote more lateral buds to sprout new branches. In summer, when the growth of broken branches comes to an end, cut off the top 2-3 buds from the developing branches over 50 cm to promote the germination of lateral buds, enrich branches and increase the number of branches in the coming year. In autumn, the unfinished part at the top of the elongated developing branches or one-third to one-quarter of the branch length is cut off and cut on the plump outer buds in the middle and upper parts, so that the crown of the tree is expanded year by year and more developing branches are extracted. 1 year-old thin and weak branches that are too dense can be cut off appropriately.
2. Pruning of fruiting branches: The top bud of the fruiting mother branch of walnut is mixed flower bud, so it is generally not allowed to prune every branch, only the dense twigs, dead branches, disease and insect branches and overlapping branches are pruned, so as to make ventilation transparent and promote the growth of fully robust fruiting mother branches and developing branches.
(1) Pruning of fruiting mother branches: robust branches that grow around the crown 1 year are usually fruiting mother branches in the second year, and are generally not cut short. However, if there are too many fruiting mother branches, the crown will be closed, which will affect ventilation and light transmission. Therefore, it is necessary to prune some fine fruiting mother branches appropriately to stabilize the yield and promote the normal development of the tree.
(2) Pruning of extended branches: For the 15-30-year-old trees in full fruit, the 1 year-old extended branches extracted from the top of each main branch outside the crown can be cut short 2-3 buds below the terminal bud. If the top branches are not full, they can be cut off at the full buds to enlarge the crown and increase the fruiting parts.
(3) Pruning of long branches: Long branches are mostly germinated from hidden buds on the main branches of the inner room, which are more common in mature trees and aging trees. In the past, many people cut off contacts with the base, which is called "cleaning the room". In recent years, we have begun to use the fruits of long branches. According to the experience of Hebei, Shandong and other provinces, according to the growth position and growth intensity, the long branches in the open part of the inner chamber can be shortened by one-half to one-third, and fruiting branches can be formed after 2-3 years, which can supplement the gap, expand the fruiting range and achieve the purpose of three-dimensional fruiting.
(4) Pruning of drooping branches: retract at the bifurcation, and cut off dead branches of diseases and pests at the same time. Too dense drooping branches should be cut off year by year.
Walnut is a deep-rooted fruit tree, which needs deep and fertile soil and likes warm and humid climate. It is a semi-positive plant, and its pH value is 5.5 ~ 7.0, and 6 ~ 7 is the best. It is planted in low mountains with an altitude of 300 ~ 700 meters, with high and stable yield. The propagation of Carya cathayensis mainly depends on sowing and seedling raising. Can also be cut, roots or branches 1 ~ 2 years old. Transplanting and planting can be carried out after defoliation in autumn and before germination in the following spring, but planting in spring should be done sooner rather than later.
Carya is Carya of Juglandaceae. There are about 20 species, 4 of which are native to China. 1984 Zhejiang Forestry College discovered a new species in Jinzhai, Anhui Province. There are 1 1 species native to North America.
I. Distribution area
China's pecans are mainly distributed in Lin 'an, Chun 'an, Ji 'an and Tonglu in Zhejiang and Ningguo, Shexian, Jixi and Jingde in Anhui. In recent years, the planting area in Zhejiang Province is about 250,500 mu, with a total output of 6,300 tons, accounting for 85% of the total national pecan production, mainly produced in Lin 'an County.
Second, the significance of cultivation
Carya cathayensis nuts are delicious and edible, with an egg content of 7.23% and an oil content of 48% ~ 53%, most of which reach 69%. 27 ~ 30 kg of high-grade edible oil and industrial oil can be squeezed out per 100 kg of nuts. Shell can be used to make activated carbon, involucre can extract tannin, and wood can be used to make furniture and military industry.
Carya cathayensis has the characteristics of shade tolerance and strong adaptability to soil pH, and is a good tree species for building economic forests on barren hills and slopes. It also has the characteristics of late flowering, early harvest, no frost and cold damage in the fruit-bearing growth period, small shell and fruit volume, storage and transportation resistance and long service life, and can be harvested for many years once planted.
Third, cultivate characteristics
Carya cathayensis is an anemophilous flower. During male and female flowers and flowering, it is rainy, the temperature is lower than 10℃, or the temperature drops greatly, which is extremely unfavorable for pollination and fruit setting. Carya cathayensis is tall and dry, the terminal buds and nearby buds are easy to germinate, and the germination ability in the middle and lower parts is weak. In order to promote the early fruiting of young trees, the backbone branches can be appropriately shortened. For the convenience of management, the top of the tree is generally picked at the full fruit stage (10 ~ 15), and the height of the tree is controlled at about 5 meters.
Carya cathayensis is a deep-rooted fruit tree, which needs deep and fertile soil and likes warm and humid climate. It is a semi-positive plant, and its pH value is 5.5 ~ 7.0, and 6 ~ 7 is the best. It is planted in low mountains with an altitude of 300 ~ 700 meters, with high and stable yield. The propagation of Carya cathayensis mainly depends on sowing and seedling raising. Can also be cut, roots or branches 1 ~ 2 years old. Transplanting and planting can be carried out after defoliation in autumn and before germination in the following spring, but planting in spring should be done sooner rather than later.
Four, the main varieties and excellent varieties
1. Main types
C. Populus davidiana is about 30 meters high, with smooth epidermis, odd pinnate compound leaves and 5-7 leaflets. Nuts are oval or broadly oval, with large tops and thick shells. 1 kg has about 292 nuts. The nucleolus is very large, usually with four cracks. It tastes delicious after astringency removal, and can be used for frying or processing sweets and cakes, and can also be used for oil extraction.
2. Excellent varieties
Most round pecans belong to this type. The top of the nut is oval, the top of the fruit is sharp, the left and right halves are skewed, the size is asymmetric, and the shell is thick. The inner wall has two large partitions and six small partitions, and the shell is easy to peel and the nut is often complete.
The nut of flat fruit is oblate, with a slightly prominent top, a round base and a thick shell. The interior wall is divided into three big partitions and then into nine small partitions. Because there are many grooves in the shell, it is difficult to peel the shell, and most of the peeled kernels are incomplete.
Thin-shell species are mainly produced in Lin 'an area, with shell thickness of 0.08 ~ 0. 10 cm, kernel yield of 46%, oil yield of 72% and good quality. At present, the number of plants is small, so it should be propagated and popularized vigorously.
3. Scorch, Illinois
Carya cathayensis and Carya cathayensis belong to different species Also known as pecan, pecan. Native to the Mississippi River valley and the southern Gulf of Mexico. According to Professor Wu Gengmin's investigation, around 1900, American female missionaries were introduced to Jiangyin, Jiangsu, China. At present, the introduction is widely distributed in China, and there are many plants in Nanjing, Jiangyin, Huai 'an, Hangzhou, Lin 'an, Wenzhou and Xiamen, but no commodity base has been established so far.
Pecan nuts are delicious, which is the best quality among walnut trees. It can be eaten raw, fried or made into candy, and can also be used to extract oil. Wood is strong, tough and dense, and can be used for national defense or making exquisite furniture. Magnificent trees are suitable for street trees or trees beside rivers and reservoirs, and are easy to reproduce. Besides grafting, it can also take root by cutting, which is suitable for planting in the warm and humid environment in the south.
Many varieties of Carya cathayensis can't blossom at the same time because of the tall trees, inconvenient management and late entry into the high-yield period, so artificial pollination is needed to improve the fruit-setting rate.
Carya cathayensis is not produced as a processed commodity in China. After being graded, washed and shelled by factories in the United States, nuts are mostly used as raw materials for making candy, bread, ice cream or snacks.
Verb (short for verb) Harvest, process and sell.
Usually, the color of the involucre of the fruit changes from green or blue-green to yellow-brown, that is, it is mature. If the empty fruit is caused by poor fertilization and other reasons, it is not easy to separate it, so that good fruit and bad fruit can be distinguished. The pruned nuts should be steamed immediately, otherwise they will go bad easily. Nuts that can't be treated in time should be thinly covered in a ventilated place indoors and dried in the shade.
At present, the main processed products in China are salt and pepper hickory, hickory candy and so on. Due to the limited output, the demand exceeds supply, and the market prospect is good.
Treatment measures of walnut trees after freezing injury
After the walnut tree is frostbitten, anti-freezing measures must be taken as soon as possible to avoid affecting the yield and diseases in the coming year.
1, luggage protection
(1) 4-5 Freeze-damaged walnut trees. In order to prevent the frost damage from aggravating and rotting, we should immediately apply tree protector or paint the trunk.
(2) Clear the snow around the trunk in time after the snow, and the ground temperature will rise. After the surface is thawed, the trees less than 4 years old will be covered with plastic film with the trunk as the center, covering an area of about 1 m2.
2. Fertilizer and water
(1) Fertilize and water the soil immediately after thawing and before germination (first half of March). The annular or radial fertilization ditch method was adopted, and 50 kg of organic fertilizer and 0/-2 kg of urea were applied to the big trees. Apply 0.2-0.5 kg of urea to young trees and water them immediately after fertilization. Spraying the mixed solution of urea and potassium dihydrogen phosphate with the concentration of 0. 1-0.3% on the leaves, and topdressing outside the roots.
(2) After the soil is thawed, the pine trees and conditional woodlands should be ploughed and loosened as soon as possible.
3, timely pruning
(1) Before budding and leaf spreading (from mid-late March to mid-April), determine the frozen parts of branches of trees with frost damage level 2 or above, and prune them appropriately. Cut off the dead parts of branches, and apply 50 times solution of 3-5 degree sulfur mixed solution or 50% thiophanate-methyl wettable powder to the cut mouth for disinfection. Transport the cut branches out of the forest land and burn them centrally.
(2) In early and mid-May, select and keep the sprouting and tender branches on the pruned branches. Select and cultivate new trunk branches and fruiting branches, pruning branches, upright branches, over-dense branches, cross branches, etc. And restore the shape and shape of the tree as soon as possible.
(3) In the middle and late May, select and preserve the whole overground part and grafted part of frozen seedlings and saplings, select the trunk of new saplings to be cultivated and new branches to be grafted, cut off other new branches and bud grafting in summer.
4. Prevention and control of decay
(1) Walnut trees are prone to secondary diseases-rot after freezing injury. In early spring (early and middle April), once the rot disease is found, it should be prevented in time;
Scrape off the diseased spots: scrape off the rotten diseased spots with a sharp knife, and the scraping mouth becomes a "long shuttle shape" with smooth and complete edges. Scrape 0.5㎝ wide intact cortex from the lesion, leaving no diseased tissue.
Usage: Use 50 times solution of Shuguan bacteria or 50% thiophanate methyl wettable powder or 50% bacitracin wettable powder or 5- 10 Baume mixture to disinfect the scraped wound, and then brush Bordeaux solution to protect the wound.
5. Scratch protection
After curettage, wrap curettage with cloth or dark plastic strips to facilitate wound healing. Collect the scraped diseased tissues in a centralized way and transport them out of the forest land for burning. Never leave the scraped diseased tissue in the woodland. To prevent rot, we should "scrape early and scrape small" (China Plant Protection Network)
Cultivation techniques:
1, planting time:
Walnut is suitable for growing on warm sandy soil and black loam with deep soil layer and good drainage, and should be planted on sunny slopes and leeward. To develop walnuts in barren hills, we must first build terraces, dig large fish scale pits and do a good job in soil and water conservation. Planting time: early planting in spring after soil thawing, early planting in autumn after defoliation and early planting after soil freezing, and early planting in autumn before soil freezing after defoliation. In arid areas in spring, autumn sowing has a higher survival rate than spring sowing. The second spring sprouted early and grew strong. Seedlings planted in autumn should be ridged to prevent drainage. Methods: The trunk of seedlings was bent into an arch to fix the soil, and the trunk was not exposed. The next spring, I broke through the ground and straightened the trunk.
2. Planting method:
The taproot of walnut seedlings is very long, and the pit depth and width are 0.8- 1 m respectively. First, fill the topsoil and base fertilizer at the bottom of the pit, about 20 cm away from the pit surface. When planting, use scissors to cut off the seedlings with soaked roots and fully absorbed water, put them in the into the pit vertically, spread the roots around, then fill them until they are flush with the ground, then fill them with water and seal them.
Second, plastic trimming:
It is an important cultivation technique to make walnut bear fruit early, high and stable yield and reasonable shaping and pruning. The pruning period of walnut is different from that of ordinary fruit trees. This is done after the fruit is picked and before the leaves turn yellow. In North China, it is best to prune between "white dew" and "cold dew". Pruning at this time, although the temperature is low, the wound heals slowly, but the nutrient loss is less. Young trees can be pruned early because they have no fruit, and they can start from the "Summer Festival". Spring pruning is generally carried out around the "long summer". It's too late, because the branches and leaves are too big and consume too many nutrients, which is not conducive to the growth of trees.
1, young tree pruning: mainly to cultivate tree skeleton, lay a good foundation, quickly expand crown, and promote early fruiting and high yield. The tree shape of walnut is generally sparse and scattered, natural and happy.
(1) Sparse layer dispersion: the central dominant tree is obvious, and 5-7 main branches are divided into 2-3 layers, so that there are many branches in the tree, the crown is large and the yield is high. The key points of plastic surgery are: setting the height of trunk 1.5-2.5 meters, poor soil conditions, keeping trunk low, and rationally allocating the position and direction of main branches. The main branch spacing1-1.5m should not be too close. The first of the three main branches of the base is about 1.5m away from the main branch. If it is too close, it will form a door side, and the branch spacing around the crown should be reduced. Attention should be paid to maintaining the growth advantages of major central branches. Under normal circumstances, you can't change your head easily, which is an important feature different from other fruit tree pruning.
(2) Natural jubilation: the central leadership trunk is not obvious, with 2-3 main branches in a 2-fork or 3-fork structure. In order to accelerate the expansion of young walnut trees, it is necessary to pour mace to raise seedlings. Cut off the top 2-3 buds from the developing branches above 0 cm to promote the germination of lateral buds, enrich branches and increase the number of branches in the coming year. Before defoliation, autumn pruning is carried out, and the top of the extended developing branches or the unfinished part of one-third to one-quarter branches is cut off, and the cut is made on the plump outer buds in the middle and upper parts, so as to expand the crown year by year and extract more developing branches. 1 year-old thin and weak branches that are too dense can be cut off appropriately.
2. Pruning of fruiting branches: The top bud of the fruiting mother branch of walnut is mixed flower bud, so it is generally not allowed to prune every branch, only the dense twigs, dead branches, disease and insect branches and overlapping branches are pruned, so as to make ventilation transparent and promote the growth of fully robust fruiting mother branches and developing branches.
(1) Pruning of fruiting mother branches: robust branches that grow around the crown 1 year are usually fruiting mother branches in the second year, and are generally not cut short. However, if there are too many fruiting mother branches, the crown will be closed, which will affect ventilation and light transmission. Therefore, it is necessary to prune some fine fruiting mother branches appropriately to stabilize the yield and promote the normal development of the tree.
(2) Pruning of extended branches: For the 15-30-year-old trees in full fruit, the 1 year-old extended branches extracted from the top of each main branch outside the crown can be cut short 2-3 buds below the terminal bud. If the top branches are not full, they can be cut off at the full buds to enlarge the crown and increase the fruiting parts.
(3) Pruning of long branches: Long branches are mostly germinated from hidden buds on the main branches of the inner room, which are more common in mature trees and aging trees. In the past, many people cut off contacts with the base, which is called "cleaning the room". In recent years, we have begun to use the fruits of long branches. According to the experience of Hebei, Shandong and other provinces, according to the growth position and growth intensity, the long branches in the open part of the inner chamber can be shortened by one-half to one-third, and fruiting branches can be formed after 2-3 years, which can supplement the gap, expand the fruiting range and achieve the purpose of three-dimensional fruiting.
(4) Pruning of drooping branches: retract at the bifurcation, and cut off dead branches of diseases and pests at the same time. Too dense drooping branches should be cut off year by year.
Walnut is a deep-rooted fruit tree, which needs deep and fertile soil and likes warm and humid climate. It is a semi-positive plant, and its pH value is 5.5 ~ 7.0, and 6 ~ 7 is the best. It is planted in low mountains with an altitude of 300 ~ 700 meters, with high and stable yield. The propagation of Carya cathayensis mainly depends on sowing and seedling raising. Can also be cut, roots or branches 1 ~ 2 years old. Transplanting and planting can be carried out after defoliation in autumn and before germination in the following spring, but planting in spring should be done sooner rather than later.
Several excellent varieties of walnut
Several excellent varieties of walnut;
1, Xiangling: The tree is vigorous, erect and medium-ripe, with a single grain weight of 6.6 grams, bearing fruit in two years and a single plant yield of 6 kilograms in three years. Its shell is beautiful, the kernel rate is 60%, the flavor is good and the disease resistance is strong.
2. Liaohe 1: Late-maturing variety, with average single grain weight of 6g, yield of 5kg per mu in three years, and kernel rate of 55%.
3. Liaohe No.4: a late-maturing variety with an average fruit weight of 6.62g, high yield, 3-year-old plant yield of 5.5kg, kernel rate of 57%, and strong disease resistance.
4. Lin Zhong 1: Medium-mature variety, with an average single grain weight of 6.6 grams, kernel yield of 55%, and three-year yield per plant 10 kg.
5. Yuanfeng: The crown is semicircular, the branches are dense and short, and it is slightly brownish green, which is a male early-bearing variety. The measured flower bud rate is 64.2%, the average fruit setting rate per branch is 1.95, and the average fruit weight of nuts is 10.27- 13.48g, with 78 nuts per kg. The grain is full, yellow-skinned, slightly astringent and of medium quality. The grain yield is 46.25-50.5%, the grain fat content is 68.66%, the protein 19.23%, and the average grain yield is 385-400g/m2. The main characteristics of Yuanfeng walnut are high yield, resistance to black spot and anthracnose, and moderate nut quality.
6. Fenghui: Fenghui walnut is an early food species, with upright tree posture and medium growth potential. Its crown is semi-circular, mainly with short branches and middle branches, with an average fruit setting of 1.6/fruit and oblong nuts, with an average single fruit weight of 9.5- 15.4g and 75- 105 per kilogram. Shell thickness of 0.9~ 1.0mm is very easy to pick kernels, and kernels can be taken as a whole. Endotesta is light yellow, full of seeds, beautiful and fragrant, and it has no astringency. Grain yield is 54.6~6 1.2%, grain fat content is 6 1.7%, and protein content is 22.9%, with average crown width per square meter.
Walnut planting techniques:
I. Garden Construction and Planting
1. Garden selection
Walnut trees do not require high environmental conditions. It can be planted in areas where the annual average temperature is 9 ~ 16℃, the annual rainfall is 500 ~ 800 mm, and the altitude is 600 ~1200m. Walnut has wide adaptability to soil, but because it is a deep-rooted fruit tree with weak resistance, it is more suitable to choose deep and fertile loam with strong water retention. Walnut is a light-loving fruit tree, which needs sufficient light. It is best to choose the south slope to build a garden in mountainous areas.
2. Planting method and density:
The cultivation method of walnut should be determined according to the site conditions and management level. In hilly and mountainous areas with general soil, fertilizer and water conditions, the plant spacing can be 3 m× 4 m, and in areas with deep soil layer, good soil quality and high fertility, the plant spacing can be 3m×5m, or 5m×6m or 6 m× 7 m.
3. Pollination tree configuration:
Walnut is monoecious, cross-pollinated, and male and female flowers often do not meet. Moreover, walnut flowers are wind-borne flowers with large and heavy pollen grains and short effective pollination distance. It is best to choose 2 ~ 3 varieties that can provide pollination opportunities for each other when building a garden. If you choose a variety as the main planting variety, you can arrange a row of pollinated varieties every 2 ~ 3 rows. In principle, the maximum distance between main cultivars and pollinated cultivars should be less than 50m, and the ratio of pollinated cultivars should be 2 ~ 3: 1.
Second, planting techniques
1. Planting date:
Walnut has two planting periods: spring planting and autumn planting. Autumn planting is especially suitable for the northern spring drought and windy areas. Trees planted in autumn germinate early and grow vigorously, but pay attention to cold protection in winter (burying soil is the best method). It is suitable for spring sowing in areas with low temperature, good moisture conservation, deep frozen soil layer and windy winter. Spring planting can be carried out after the soil thaws in early spring.
2. Planting method:
Before planting, a 1m square planting pit should be dug, with surface soil on one side and deep soil on the other. At the same time, cut off the injured roots and rotten roots of the seedlings. Soak in water for half a day or soak the root system in mud to make the root system fully absorb water in order to survive.
When planting, the topsoil is mixed with soil manure or manure to fill the pit bottom, and then the seedlings are put in. It is best for two people to plant seedlings together, one to support the seedlings and the other to fill the soil. Nurses should master the planting depth and stretch their roots with their hands. When the roots of seedlings are completely buried by fine soil, the seedlings should be gently pulled upward to make the soil closely connected with the roots, and then covered with soil and buried densely. In this way, each root is scattered, the absorption range is large, and the seedlings are easy to survive.
The depth of hole seedlings should be the same as that of nursery, too shallow is vulnerable to drought, freezing injury and diseases, too deep, slow seedling emergence and unhealthy seedling growth. However, the soil quality varies from place to place, and the planting depth can also be different. Generally, the planting depth in sandy land can be slightly deeper, and the clay land is slightly shallower.
After planting, repair the tree tray, fully irrigate and pay attention to irrigation, otherwise the survival will be affected. After the water seeps out, cover a little soil under the tree tray and cover it with plastic film in spring.
For fields with clayey soil or gravelly substrate, it is necessary to appropriately increase planting holes, improve the soil by changing soil and increasing fertilizer, and create conditions for the growth of roots and seedlings in the future, otherwise even if the plants survive, the effect will be very poor.
3. Post-planting management:
(1) Check the survival and replant. Check the survival situation in time. If the seedlings die, they should be replanted in time.
(2) Before the soil freezes, the seedlings planted in autumn should be bent, buried with soil or covered with plastic bags. Plastic film should be made into a cylinder with a diameter of 20 ~ 25 cm, 7 ~ 8 cm higher than the tree, and filled with wet soil. Uncover the film, remove the soil and release the seedlings before germination in the coming year. For the seedlings planted in spring, in order to prevent the strong wind in spring, you can put a newspaper on the trunk, make it into a cylinder with one end sealed and a diameter of about 2cm, or buy a commercially available cold-proof plastic bag.
(3) After the seedlings germinate, they can be aired. For the height of drying, please refer to the plastic trimming section. The distance between the incision and the bud should be about 2cm, and the incision should be dried before painting.
Third, the management of young trees and trees at the initial stage of fruiting.
At the initial stage of walnut fruit bearing, the tree is in a stage where vegetative growth is greater than reproductive growth. The well-developed annual rings at this stage directly affect the formation of tree and the improvement of yield. In order to ensure the normal development of trees, prevent "small old trees" or die, and lay a good foundation for high and stable yield in the future. Therefore, the comprehensive management of young walnut trees should be strengthened after the garden is built.
1. Soil management:
Soil is one of the important environmental conditions for the growth of walnut trees. Soil conditions and management level restrict the growth and fruiting of walnut trees. In order to promote the growth of young trees, intertillage and weeding should be carried out many times every year to reduce soil moisture evaporation, improve soil ventilation, promote the decomposition of insoluble nutrients in soil and improve soil fertility. Generally, "weeding, hoeing after rain and hoeing after irrigation" should be done in the growing season every year. If there is not enough manpower, weeding must be done twice a year, once after flowering and once before lodging. These two weeding times should not only be timely, but also be deeply ploughed. So as to effectively control gras shortage and achieve that purposes of loosen soil, storing water and keeping moisture.
2. Garden fertilization:
Types of fertilizers: Different types of fertilizers have different application periods. According to the different nutrients contained in fertilizers, fertilizers are divided into two categories:
① Organic fertilizers are manure, compost, human excrement, cake fertilizer, green manure, etc. Organic fertilizer has complete nutrients, including not only main elements such as nitrogen, phosphorus and potassium, but also a variety of trace elements. Organic fertilizer is efficient and long-lasting, which can improve soil structure and regulate soil temperature. Fertilization should be based on organic fertilizer every year. Walnut orchards are mostly mountainous and hilly areas, with poor soil layer and low organic matter content. In order to ensure high and stable yield of walnut, a large amount of organic fertilizer should be applied every year.
② Inorganic fertilizer is generally called "chemical fertilizer". Generally, it has the characteristics of high nutrient content, strong quick effect and convenient application. However, this fertilizer contains no organic matter, only one or several main nutrients. On the one hand, long-term single use will harden the soil, on the other hand, it will unbalance the nutrition of plants. Therefore, it is generally used in conjunction with organic fertilizer. Inorganic fertilizer has fast effect, but its duration is short.
3. Fertilization period:
Walnut continuously absorbs various nutrients in the soil during the whole growth period. Its absorption of nutrients is unbalanced at different ages in a year, and there is a most critical period. Generally, from mid-August to 10, the soil moisture condition is also good, the roots are at the peak of autumn growth activities, and trees accumulate and store more nutrients, which is beneficial to growth and fruiting. Applying organic fertilizer in autumn can improve soil porosity, preserve moisture by snow in orchard, prevent soil drought in winter and spring, raise ground temperature and reduce rhizosphere freezing injury.
Topdressing: mainly topdressing chemical fertilizer, especially nitrogen fertilizer. Topdressing is applied in the critical period of walnut fertilizer demand or to adjust the relationship between growth and fruit, which is a supplement to the lack of base fertilizer. Topdressing is mainly carried out in the growth period of trees to ensure the high yield and robust growth of walnuts in that year. According to the growth and fruiting characteristics of young walnut trees, topdressing can be divided into the following three periods.
1) Before flowering, this period is the first growth period of roots, and it is also the competition period of nutrients needed for germination and flowering. Topdressing at this stage is beneficial to promote growth, reduce flower drop and improve fruit setting rate. This topdressing is mainly available nitrogen fertilizer, and ammonium sulfate, ammonium nitrate and urea can all be topdressing. The time is in late March. Fertilization amount is 30% of annual fertilization amount.
2) The main function after flowering is to reduce fruit drop, promote the rapid expansion of young fruits and the growth of new shoots, and prepare for flower bud differentiation. Available nitrogen fertilizer is the main type of topdressing, and appropriate phosphorus and potassium fertilizer should be applied at the same time. Top dressing accounts for 20% of the annual top dressing.
3) Generally, after entering the hard core stage, the fruit growth gradually slows down and the seeds begin to enrich. At this time, topdressing can meet a lot of nutrients needed for seed development. At the same time, it is also a critical period for flower bud differentiation, and sufficient carbohydrate accumulation is also conducive to flower bud differentiation, laying the foundation for high and stable yield in the coming year. It is mainly composed of compound fertilizer of nitrogen, phosphorus and potassium. Top dressing accounts for 20% of the annual top dressing.
4. Fertilization amount:
The fertilizer requirement of walnut trees varies with the age, tree vigor, fruit yield and environmental conditions. In medium fertility soil, urea is about100g, calcium superphosphate is 30g, and calcium superphosphate10g; Apply 10% potassium nitrate to each plant every year. Results In the early stage, 300g urea, 250g calcium superphosphate and 80g potassium nitrate were applied to each plant every year. The amount of base fertilizer is equivalent to 50 ~ 100 kg per plant, which is guaranteed to be applied every year.
5. Fertilization method:
① Root fertilization can adopt ring fertilization, furrow fertilization between rows, hole fertilization and radial furrow fertilization.
② foliar spraying: 0.3 ~ 0.5% urea, 0.3 ~ 0.5% potassium chloride and 1.0 ~ 3.0% calcium superphosphate leaching solution can be sprayed.
6. Orchard irrigation:
During the growth of walnut trees, the annual rainfall reaches 600 ~ 700 mm, and it is evenly distributed, which can basically meet the needs of growth and development. If the rainfall is insufficient or uneven, it needs to be supplemented by irrigation, and the regulation of soil moisture should be strengthened for both young trees and big trees.
The time, quantity and method of irrigation can be determined according to local climatic conditions, soil moisture, rainfall and the growth and development of walnuts. Irrigation is usually 3 ~ 4 times a year.
Irrigation period:
① Before and after irrigation in early spring, walnut needs to complete the complicated process of germination, leaf spreading, flowering and new shoot elongation. During this period, the northern region is the spring drought season. Irrigation in early spring before germination is very beneficial to promote early growth and prevent the harm of cold spring and late frost.
(2) It is easy to have high temperature and dry weather after irrigation in the northern region in midsummer and long summer, at this time, the leaves are easy to wilt, which hinders the normal transpiration and photosynthetic function. Especially for the planted 1 ~ 2-year-old trees, the root system is shallow and the early resistance is poor, so irrigation is needed at this stage.
(3) Irrigation before winter and sufficient irrigation before soil freezing, combined with base fertilizer application in autumn, can promote root absorption, increase the accumulation of stored nutrients and improve the accumulation level of trees.