Walnuts are an important oil crop with high economic value. Walnuts are rich in nutrients and are widely favored by the market.
Walnut trees are strong, adaptable to the environment, have few diseases and insect pests, save labor, are easy to store and transport fruits, have a long life, and are managed differently in different seasons.
1.1 Moisture management
In late March to early April in spring, germination watering is required, especially in years when there is insufficient rain, it is necessary to water enough germination water to promote the differentiation of walnut buds, and the rapid growth of new branches and leaves, and the scope of germination watering includes young trees and fruiting trees.
Watering the sprouts can also lower the soil temperature, delaying the flowering period to avoid the hazards of late frosts.
In order to prevent the harm of rhizome weevil and aromatic wood beetle moth, it is necessary to turn the soil near the roots outward between early and mid-April to reduce the soil moisture content at the base of the roots, so as to achieve the purpose of controlling the above insect pests.
1.2 Fertilization
Walnut fertilization is mainly nitrogen fertilizer, such as urea, the amount of fertilizer of the fruit tree should be based on its yield as the standard, before the walnut germination, combined with the expansion tray, the application of ammonium bicarbonate 2 500 ~ 7 500 g / plant, sprinkling or ring furrow fertilization.
The amount of fertilization of young trees should refer to their diameter size, and the standard for applying nitrogen fertilizer of 50 g/cm is the standard. In order to prevent root burning, it is advisable to apply fertilizer to a distance of 40 cm from the trunk.
1.3 Shaping
Walnut trees should adopt different shaping methods in different periods, in the young tree stage, should be mainly to cultivate tree shape, not only to consider the opening angle, but also to properly cut the backbone branches and leaves, increase the proportion of short and medium branches, and promote their growth and formation as soon as possible, early fruit;
During the fruiting period of walnut trees, in order to maintain the overall growth trend and prolong the fruiting period, it should be appropriately truncated and retracted, and the over-dense branches and leaves should be cut off to ensure its good permeability.
Clean up in time after pruning, and apply callus antiseptic film to large wounds to protect the growth of healing tissues and prevent bacterial infestation.
1.4 Pest control
Clean up the weeds and fallen leaves in the garden in time, and concentrate on burning or fertilizer. It is recommended to spray 3 to 5 ° bé stone sulfur compound in late March, or 50% carbendazim wettable powder 1 000 times liquid, etc.
For the prevention and treatment of black spot disease and decay disease, you can use a knife to cut deep into the wooden part of the diseased place, and then apply the stone sulfur compound or carbendazim to the incision, and the incision interval is 1 cm.
Whitening can prevent the egg-laying hazards of walnut gidding insects, and is applied to the trunk of all small young trees and large trees below 1.2 m.
2.1 Soil fertilizer and water management
When expanding the walnut tree, the weeding work should be done well. In the period of drought and little rainfall, watering should be done in time to ensure soil moisture in the tree cavity and avoid excessive drought affecting the normal development of walnut trees in summer.
Walnut trees are still dominated by topdressing in summer, mainly applied during the rapid growth period of the tree body, which is a supplement to the base fertilizer in spring, and the fertilizer is mainly fast-acting fertilizers such as urea, compound fertilizer and ammonium bicarbonate.
Summer to topdressing 2 to 3 times is appropriate, according to the different fertility of the garden appropriate adjustment of the amount of fertilization, in general, with the growth of the number of years, the higher the amount of topdressing, specifically for the two-year annual consumption of 300g / year,
The three-year consumption is 500 g/year, the four-year consumption is 1 000-2 000 g/year, and the dosage is 5 000-7 000 g/year for more than ten years.
The first fertilization is mainly based on fast-available nitrogen fertilizer, the time is from the end of March to the beginning of April, in order to promote the growth of new shoots and flowering and fruit setting, and the amount of fertilizer should be sufficient, accounting for about 1/2 of the total fertilization of the year;
The second fertilization is still based on fast-available nitrogen fertilizer, the time is better from the end of May to the beginning of June, if it is the walnut fruiting period, nitrogen, phosphorus and potassium compound fertilizer can also be applied, the main purpose is to promote the rapid development of fruit, fertilizer application accounts for about 30% of the annual consumption;
The third fertilization should be based on nitrogen, phosphorus and potassium compound fertilizer, the time is from the end of June to the beginning of July, the dosage accounts for 20% of the annual dosage, and its role is mainly to provide sufficient nutrition for fruit development to ensure that the fruit is full.
2.2 Trimming
Summer pruning of walnut trees is particularly critical, which will directly affect the growth and yield of walnuts, and the following pruning principles should be followed: retain all newly germinated new shoots, and do not prune in summer;
All the buds of the rootstock are pruned; when the walnut new shoots are in full swing, usually in May, it is necessary to pay attention to timely heart picking; in order to promote branching, it can be cut from 10 cm at the tip when the new shoots are 40 to 50 cm;
In order to ensure good permeability, densely squeezed branches should be removed in time; in order to control growth, pbo (compound plant growth hormone) 200 to 300 times liquid should be sprayed in early July, and branches should be taken in August and September to achieve the purpose of flower bud differentiation.
2.3 Pest control
The main diseases that harm walnut trees are anthrax, black spot disease and decay disease, and the main insect pests include the American white moth, cloud-spotted sky cow, walnut lifting moth, thorn moth and scarab beetle.
For the prevention and treatment of anthrax and nigra, the spots should be scraped off in time after the appearance of symptoms of the disease, and 70% methyl tolbuzin, 50% carbendazim wettable powder 1 000 times liquid should be sprayed at the diseased place, or 5 to 10 ° bé stone sulfur compound should be applied.
For the insect infestation of cloud-spotted cattle, it should be manually culled in time, or inject 50% dichlorvos 50 times liquid into the worm hole for poisoning, or use a cotton ball soaked with insecticide to block the worm hole.
For the American white moth, 1 500 times of the liquid of urea no. 3 should be sprayed in time and the mesh curtain should be cut off. In order to do a good job in the prevention and control of insect pests such as lifting moths, stinging moths, scarab beetles, etc., spraying octyl thion liquid should be sprayed in mid-to-late May, and the urea or permethrin drug solution should be applied in early June.
3.1 Soil fertilizer and water management
Walnut tree autumn and winter fertilization should be selected after fruit harvest to before the fall of leaves, can be carried out at the same time as deep ploughing, fertilizer is mainly organic fertilizer, young trees are applied 25 ~ 50 kg / plant, the first fruit stage of walnut trees applied 50 ~ 100 kg / plant, the full fruit stage of the application of 200 ~ 250 kg / plant.
And water before freezing. In order to do a good job in the winter antifreeze of young trees, it is necessary to choose different aspects of protection of young trees according to the degree of cold, and can be buried, baled and other ways to resist the cold.
3.2 Trimming
Autumn pruning time should be selected between the harvest of the fruit and the yellowing of the branches, and the winter pruning focuses on the removal of large branches, dense branches, insect disease branches, and drooping branches.
3.3 Pest control
Deep ploughing orchards, first of all, can turn the eggs of diseases and insects out of the ground, destroy their living environment, make them freeze to death or be killed, and reduce the chance of survival of diseases and insects; secondly, you can loosen the garden, enhance soil permeability, and facilitate the growth of walnut tree roots.
The trunk is whitened, and the mixture made of sulfur powder, lime and water according to the ratio of 1:10:40 is applied to the walnut trunk, which can effectively prevent rot diseases and effectively resist pests such as cloud-spotted tianniu and walnut tumor moth.
Winter scraping is particularly critical, by scraping dry warped skin, sick skin, disease spots to reduce the number of diseases and insects, scraped off the bark should be transported out of the garden in time, and burned or disinfected after landfill.