Experience of Rapid Seedling raising of Green Walnut sown in Field

After several years of experimental research, the goal of sowing green walnut in autumn and breeding walnut seedlings in one year in the field has been achieved.

1 selection and arrangement of nursery sites

In order to raise walnut seedlings, sandy soil with flat ground, convenient irrigation and drainage, deep groundwater level, deep soil layer and convenient transportation should be selected as nursery land. 667m2 applied 50kg compound fertilizer and 2000kg organic fertilizer as base fertilizer, then ploughed and raked flat, planned zoning, dug drainage ditches and irrigation canals, and set aside roads.

2 seed selection and treatment

Green walnut, which is pest-free and fully mature, was harvested from robust trees in early September. It is best to sow seeds with harvest and store temporarily in a ventilated and cool place to prevent rot and mildew. If the quantity is too large to sow in time, you can also use a special walnut peeling machine for peeling treatment, and then store it in a ventilated and cool place, and remember not to expose it to the sun. Before sowing, the seeds should be picked and graded according to size, and the residual fruits such as diseases, insect pests and rotten fruits should be removed. In order to prevent rodent and bird damage, the seeds should be mixed or sprayed with pesticides before sowing.

3 sowing

Sowing in the first and middle of September, the plant distance was 15-20cm and the row distance was 40-45cm, which was flexibly mastered according to the fertility conditions. Wide and narrow row sowing can be carried out, first, it can improve ventilation and light transmission conditions, and second, it is easier to operate when grafting in the future. After the ground is leveled, spread white thread according to the designed row spacing, open the shallow trench of 5~10cm, and put the green walnut (or peeled nut) along the groove. The suture line of the seed is perpendicular to the ground and the direction of the seed tip is the same. After being set up, soil is taken from both sides to cover it to form a ridge higher than the 10~15cm of the ground. If wide and narrow rows are used, two narrow rows should be covered under a ridge. Water should be watered once according to soil moisture to ensure that there is no drought, so as not to affect the normal development of seeds.

4Seedling stage management

After 30 days of sowing, green walnut seedlings began to emerge one after another, and about 80% of the seedlings were exposed to the ground in 50 days. Due to the poor degree of Lignification, the aboveground parts will freeze to death in winter of that year. Cover it all with plastic film before freezing. In late March of the following year, buds grow out one after another. At this time, we should always pay attention to observation and tear the plastic film at the place of emergence in time every morning to prevent high temperature from burning the seedlings. The seedlings have basically come out in the first ten days of April. Spraying "92 ○" amino acid foliar fertilizer 30mL/667m2 or 0.3% urea solution once in late April and mid-May respectively to promote the rapid growth of seedlings, and at the same time pay attention to weeding and watering.

5 grafting

In the middle and last ten days of June, the grafting began when the seedlings with the ground diameter above 0.7cm accounted for more than 80%, and the grafting task was completed before July 15. Select the buds in the middle and upper part of the robust one-year-old branches on the mother tree or the buds in the middle and upper parts of the new branches on the improved seedlings, and pick the heart one week before grafting to promote the buds to be full. Square bud grafting was used in the grafting method. Take 2-3.5cm square sprouts with sprouts and take them with you. Leave a drain on the rootstock and tie it tightly with plastic strips from bottom to top to expose the buds, especially around the bud base.

6. After-service management

1) shearing anvil. After the completion of grafting, 2-3 compound leaves were left above the interface to cut the rootstock, and all the leaves below the grafting interface were removed. At the same time, the sprouts should be wiped out in time. About 10 days after that, the grafted buds began to germinate, and 3cm was left above the grafting interface to cut the rootstock twice to force the buds to germinate. Continue to smear buds and remove sprouting after the second cutting of the anvil.

2) unbind. When the 10cm of the grafting bud is high, use a blade to cut the back of the grafting bud from bottom to top to release the bound plastic sheet.

3) daily management. Timely ploughing and weeding, control of diseases and insect pests, in case of drought, timely watering.

7 out of the nursery

Grafted seedlings can come out of the nursery in the first ten days of November. The average height above the grafting interface is 35-40cm, and the highest is above 80cm. The root system should be protected when digging seedlings, and it is required to irrigate once a week before seedling emergence, so that the seedlings can absorb enough water and make it easy to dig. According to the transportation requirements and the size of the seedlings, the grafted seedlings were bundled into a bundle of 25 or 50 plants. Different varieties are bundled and labeled.