This seedling was carried out in Baiwa Forest Farm of Jinxiang County from 2003 to 2005. The forest farm is located in the southwest of Shandong, 4 kilometers south of Mamiao Township, Jinxiang County, with east longitude 1 17 06' and north latitude 35 25'. The soil is sandy fluvo-aquic soil with PH value of 7.5-8.2, groundwater level of 2-3m and salt content of 0.8- 1.3.
2.2 Selection of rootstocks
In order to meet the requirements of the current garden seedling standard, the rootstock should be a 2-4-year-old elm seedling with DBH 4-6cm, height above 3m, straight stem shape, vigorous growth and no pests and diseases.
2.3 Collection of scions
In early February, 1 year-old lateral branches with strong growth and full buds were collected from elm mother trees as scions, and the incomplete parts at the top were cut off, and both ends were sealed with wax, buried in the underground shade with wet sand, or sealed with double-layer plastic, and stored at low temperature of 5℃ for later use.
2.3 Grafting method
Grafting is carried out by bagging grafting in spring. At the end of March, when the sap began to flow, according to different purposes, the rootstock was cut at the target height of grafting (2.8m for high grafting and 1.5m for low grafting), and the incision was leveled.
Cut 4-5cm long scions, and cut a double-horse-ear section at the lower end. The cut surface should be smooth and spineless, with one side thick and one side thin.
At the cut of the rootstock, pry open the cambium of the rootstock with the wedge-shaped part of the cleaver, insert the wedge-shaped section of the scion between the phloem and xylem of the rootstock, and bind it with plastic film and the scion interface. Graft three scions evenly in three different directions of each rhizome.
2.4 Post-grafting management
After grafting 10- 15 days, the graft germinated and broke the membrane and survived. After 1 month, the graft and rootstock healed completely, and the plastic film at the grafting site was cut off.
Grafted seedlings are particularly vigorous, with tall stems and large leaves, unstable joint healing parts and easy to be blown off by the wind. When the grafted branches are too long, they should be trimmed in time, leaving about 20cm of first-class branches and cutting off the rest; Second, in windy season, the grafting part should be fixed and protected with brackets; Thirdly, the sprouting of rootstock should be removed in time after grafting survival, so as not to affect the growth of grafting. 3. 1 water
After grafting, the nursery should keep the soil loose and moist, and water it in time to ensure that the grafted seedlings germinate neatly and survive. According to the wet and dry conditions of the nursery, water it in time, and water it 6-8 times in normal years and growing seasons.
3.2 Fertilization
The first topdressing was applied in the first half of May. The fertilization amount is about 15-20kg/667m2, and the types of NPK compound fertilizer are suitable. The second fertilization is in the middle of June, and the amount of fertilization is 40-50 kg/667 m2, and it is appropriate to use half of compound fertilizer and urea. The third fertilization was carried out in the middle and late July, and the amount of fertilization was 40-50 kg/667m2, with diammonium phosphate as the main fertilizer.
3.3 Loosening and weeding
Loosen the soil and mow the grass once about half a month after watering, and loosen the soil to a depth of1-2 cm; Pay special attention not to damage or loosen the seedlings. In the future, according to the situation of weeds and soil hardening, loosen the soil and weed, and weed early, small and clean every time. The main purpose of plastic pruning is to cultivate a symmetrical, plump and ornamental crown. The method is to leave two secondary side branches outside each primary side branch grafted; Prune 30-40 cm secondary lateral branches in the spring of the next year to cultivate the crown. For the partial crown, it is necessary to pull the full crown to make its growth balanced.