1. Garden selection
Walnut does not require high environmental conditions, as long as the annual average temperature is above 9 ~ 16℃ and the annual rainfall is above 800 mm, it can be planted. 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.
plant
In order to bear fruit early and improve the yield per unit area, we should carry out dwarf and close planting cultivation, select grafted seedlings and pull seedlings to realize early and high yield. Grafted seedlings can bear fruit in 2 ~ 3 years after planting, and enter the high-yield period in 4 ~ 5 years, the seedlings can bear fruit in 8 ~ 10 years, and enter the high-yield period in 15 years. At present, 3×2 (per mu11plant) is suitable for close planting gardens. Walnut is a dioecious fruit tree. Female flowers and male flowers on the same plant generally bloom at different times, so pollination between different plants is needed. Therefore, only the walnut orchards planted in pieces can achieve high yield. Walnut is most suitable for planting in autumn (September ~165438+1October) or before germination. Before planting, you can dig a big pit (80 cm long, 80 cm wide and 80 cm deep) and press in organic fertilizer, phosphate fertilizer and soil in layers, then plant it in the pit, water the roots, and cover the trees with weeds to survive. After planting, it should be fixed in time to prevent drought and seedling death.
Second, soil management.
1. culture
Deep ploughing and pressing green or organic fertilizer in walnut orchard is an effective measure for young trees to bear fruit early and big trees to produce high yield. Deep tillage can be carried out in spring, summer and autumn, before germination in spring and after rain in summer and autumn, with fertilization and burying weeds in soil. Deep tillage should be carried out year by year from the planting point, with a depth of 60 ~ 80 cm, but the thick roots with a diameter of 1 cm should not be damaged.
Young walnut trees grow slowly, so it is feasible to intercrop leguminous crops or green manure. Adult orchards are weeded with herbicides 2 ~ 3 times a year from April to September, with autumn and winter seeds 1 time.
fertilize the soil or land
The main components of walnut are nitrogen and potassium, and nitrogen is more than potassium. Increasing nitrogen application can significantly improve yield and quality. Phosphorus-deficient soil must also be supplemented with phosphorus and calcium, and organic fertilizer should be added at the same time. Fertilization of young trees should be based on the principle of thin application and diligent application. Top dressing should be applied once a month 1 time from the year of planting to germination, and base fertilizer should be applied once at the end of September. From the second year to the fourth year, fertilization should be carried out four times in March, June, August and 65438+1October every year.
Adult trees (4-5 years after grafted seedlings) can apply base fertilizer 1 time and topdressing twice a year. The base fertilizer is applied when the soil is deeply ploughed and green after fruit picking in autumn (September ~ 65438+1October), with 5000 kg of organic fertilizer (livestock manure), 50 kg of phosphate fertilizer, plant ash 100 kg and urea 15 kg. Topdressing is applied twice, the first topdressing is applied before germination, with pig manure water 1500 kg and urea 20 kg per mu. The second topdressing was carried out in hard core stage (June-July) to increase fruit weight and promote flower bud differentiation. 2500 kg of pig manure water, 30 kg of urea, 20 kg of potassium sulfate and 20 kg of calcium superphosphate can be applied per mu.
irrigate
Walnut enjoys wet, waterlogging and drought resistance, so irrigation is an effective measure to increase production. If the soil is dry and short of water during the growing period, the fruit setting rate is low, the peel is thick and the seed kernel is underdeveloped; Without irrigation after fertilization, fertilizer efficiency cannot be fully exerted. Therefore, irrigation should be done in time during flowering period, rapid fruit growth period, fertilization period and winter drought period.
Third, shaping and pruning
1. Pruning period
During dormancy, walnuts bleed and are not suitable for pruning; The most suitable pruning period is autumn, which is beneficial to the early healing of wounds in that year. Young trees do not bear fruit, and can start from the end of August in advance. Adult trees are suitable to start after fruit picking 10 months and before leaves turn yellow.
2. Young tree shaping
Walnut trunk is stout, and the advantage of terminal bud is particularly obvious. The development of terminal buds is fuller and fuller than that of lateral buds, and the crown layering is obvious. Combined with this feature, the shape of sparse layer of trunk is more suitable and easy to form. The shaping method is as follows: the height of the stem is 50-80cm (if the seedling is not high enough in that year, it can be shaped after the seedling has grown for one year), and the trunk is straightened without any pruning in that year to protect the terminal bud (if the terminal bud is damaged, it can be replaced with a strong bud first). After spring germination, the terminal bud will grow upright and serve as the main stem, and 5-6 buds at the lower part of the terminal bud will germinate lateral branches. In the second year, the second layer of main branches is also cultivated, and 2 ~ 3 main branches are left in the second layer (60 ~ 80 cm away from the first layer). In the third year, the main branch of the third layer is selected, and the main branch of 1 ~ 2 is reserved, which is 50 ~ 70 cm away from the second layer. 1 ~ 4 years, the main branches do not need pruning, and they can naturally branch and expand the crown. It usually takes 3 ~ 4 years to form, and the height of the tree is about 3 ~ 5 meters when it is formed.
Step 3 prune fruit trees
Walnut has entered the full fruit stage, the crown is still expanding, and the number of fruiting parts is increasing, which is prone to the contradiction between growth and fruiting. Ensuring high and stable yield of walnuts is the main task of pruning in this period. Therefore, in pruning, we should always pay attention to make good use of auxiliary branches and long branches, cultivate good branches, and deal with back branches and drooping branches in time.
From the initial stage of fruiting, it is necessary to cultivate strong fruiting branches in a planned way, constantly increase the fruiting parts and expand the fruiting area. Prevent the cavity of the crown from becoming empty, causing the parts to move outward. After entering the full fruit stage, it is necessary to strengthen the cultivation and rejuvenation of branches. The pruning methods of "putting first and then shrinking" and "removing back branches, leaving oblique branches and back branches" can be used in the culture branch group. Generally, no long branches are left at the beginning of the fruit, so as not to disturb the tree. The back branches should be controlled in time during the full fruit period so as not to affect the main branches and fruiting mother branches. The drooping branches are not full, the fruiting ability is poor, and only nutrients are consumed. The specific situation is specific.
Fourthly, artificial pollination and male inflorescence thinning
Artificial pollination of walnut can increase the fruit setting rate 10 ~ 30%. When the stigma of the female flower is split into an inverted eight shape and the stigma secretes a lot of mucus, the auxiliary pollination is carried out at 9 ~ 10 in the morning, and the effect is ideal.
During the development of male and female flowers, a lot of nutrients and water stored in the tree are needed, especially when the male inflorescence grows rapidly and the female flowers bloom in large numbers, the water in the tree often becomes the limiting factor for the growth and development of female flowers. Removing too many male flowers can reduce the consumption of nutrients and water in the tree, so that more nutrients and water can be supplied to the development and fruit setting of female flowers, thus improving the yield and quality, being beneficial to the growth of new shoots and enhancing the tree potential. The earlier the male flower thinning period, the more obvious the yield increase. The effect of sparse male flowers is the best from dormancy to expansion of male flower buds, but the effect of sparse male flowers is poor after the male inflorescence is obviously elongated. The number of "sparse males" should be determined according to the number of male flower buds and the ratio of mixed buds to female flower buds. If artificial pollination is not carried out, the male flowers should not be too sparse. For plants with many mixed buds and few or no male flowers, it is advisable to sparse them. The method of thinning male flowers can be combined with pruning, and the branches can be pulled down by hand with a wooden pole with a hook.
Five, pest control
1. Major diseases
1. 1 Walnut powdery mildew harms the buds and branches of leaves, causing early defoliation and even seedling death. It happened in July and August. At the beginning of the disease, the leaves turn green or cause macular. In severe cases, the leaves are twisted and shriveled, the buds germinate, and the leaves cannot be unfolded. A round white powder layer appears on the front or back of the leaf, and brown or black spots appear in the white powder in the later stage.
The control method (1) continuously removes diseased leaves and branches and burns them, strengthens management, and enhances tree vigor and disease resistance. ⑵ Spraying Bomei 0.2 ~ 0.3 degree stone sulfur mixture in early July.
1.2 walnut brown spot mainly harms leaves, fruits and twigs, and can cause deciduous leaves and dead branches. After infection, there is a small round gray brown spot in the middle, and the small black spots on the diseased spots are arranged in a concentric ring. After the disease spots increased, they withered, and the disease spots on the fruit surface were small and sunken. The tender seedlings are oval or irregular lesions. Infection occurs many times a year, with onset in May-June and peak in July-August.
Control method (1) Remove diseased leaves combined with pruning to remove diseased tips, and bury them deeply or burn them. ⑵ Spraying 1: 2: 200 times of Bordeaux solution or 500 ~ 800 times of 50% thiophanate methyl wettable powder before and after flowering and in mid-June.
1.3 walnut black spot is caused by a pathogen, also known as bacterial black spot of walnut. The main dangerous fruit is good in April-August. At the early stage of fruit damage, brown oil-soaked micro-bulges appeared on the surface, and then the diseased spots gradually expanded, subsided and turned black, with a small halo on the outer edge.
Control methods: (1) cultivate and cultivate disease-resistant varieties; (2) Keep the trees growing healthily, enhance the disease power, and timely remove pathogenic substances such as diseased fruits and leaves. ⑶ Spraying lime-broken mixture with 3 ~ 5 degrees before germination. Spraying 1: 2: 200 bordeaux solution or 500-800 times of 50% thiophanate-methyl wettable powder in May-June, and spraying 1 time before and after the young fruit stage of female flowers.
2. Main pests
2. 1 Walnut larvae harm walnut fruits and nuts, and the damaged fruits turn black and shrink, causing early fruit drop. Once a year 1 ~ 2 generations. The mature larvae overwinter in the deep soil of 65,438+0 ~ 3 cm under the crown or in weeds, stones and dead leaves, pupate in June ~ July, and lay eggs at the junction of two fruits or on the petiole of calyx depression. The newly hatched larvae climbed into the fruit after 65,438+0 ~ 3 hours, and the peak of fruit dropping was in August.
The control mode should be a combination of tree control and tree control. (1) Carefully plough the tree tray in winter and spring to eliminate the overwintering insect pupae. At the beginning of August, the fruits of pests on trees were removed and concentrated. (2) Before adult emergence, 50% phoxim emulsion can be sprayed on the soil under the liquid tree for 200 ~ 300 times, and then shallow hoe or cover with a thin layer of soil. ⑶ During the spawning period of adults, spray 2000 times every 10 ~ 15 days.
2.2 Walnut (also known as crocodile) is an important pest that harms walnut. Larvae swirls in the cortex of branches to feed, and the damaged branches swell and the epidermis turns dark brown, which directly destroys the conduction tissue, leading to dehydration and drying of large branches, and even the whole plant dies in severe cases.
Control method (1) Strengthen the cultivation management, enhance the insect resistance of trees, combine pruning and cutting off damaged branches from post-harvest to defoliation, and focus on burning. ⑵ Spraying 500 times solution of 25% carbaryl wettable powder or 800 times solution of 80% dichlorvos emulsion and 4000 times solution of 2.5% deltamethrin emulsion in adult stage.
2.3 Common thorn moths (commonly known as spicy seeds and octagonal thorns) include yellow thorn moth, blessing thorn moth, green thorn moth and flat thorn moth. The first instar larvae feed on the lower epidermis and mesophyll of leaves, leaving only reticular transparent spots on the epidermis. There are 1 ~ 2 generations in southern China every year. In early June, adults laid eggs on the back of leaves, and hatched into larvae from mid-July to early August, which began to harm leaves. In late August, the mature larvae cocoon and overwinter.
Control method (1) Combine pruning and shoveling out cocoons in autumn and bury them deeply. Adult emergence period (the first half of June), using black light to trap and kill adults every day. Remove insect leaves harmful to the colony, and immediately bury or trample the larvae to death. ⑵ When the larvae are seriously damaged, spray 600 times of 25% phoxim emulsifiable concentrate or 5000 times of 2.5% deltamethrin emulsion in the larval stage.