First, plant seedlings. Generally, after sowing, seedlings begin to emerge in 7 ~ 10 days, and 10 ~ 15 days. When the seedlings grow 2~3 true leaves, the mulch should be removed. When the seedling height 15cm, the seedling spacing 10~ 15cm, and the number of seedlings per mu is about 8000.
Second, transplantation. For green seedlings, it usually takes 3-4 years to leave the nursery. Because the top branches of seedlings have dense buds and short spacing, the trunk is easy to bend. In the spring of the following year, transplant annual seedlings according to the plant spacing of 40-50 cm and the row spacing of 70-80 cm, and cut off the trunk 3-5 cm from the ground after planting. Because Sophora japonica has the ability to germinate, it is easy to germinate in large quantities after cutting. When the sprouted branches grow to about 20cm, choose 1 upright and robust branches as the trunk, and smooth all other branches. Pay attention to tillering and lateral movement at any time in the future, and temporarily keep the weak lateral branches in the upper, middle and lower parts of the trunk, which is beneficial to prevent the trunk from bending. In this way, the seedling height in the second year can reach more than 3 meters.
Third, fertilizer and water management. The watering times of Sophora japonica seedlings should be determined according to climatic conditions, soil texture and other factors. Under normal circumstances, water should be poured 2-3 times from emergence to rainy season, and frozen water should be poured 1 time before the nursery freezes to prevent timely drainage in case of waterlogging; Before sowing, about 3000 kilograms of base fertilizer (mainly organic fertilizer or ring fertilizer) should be applied to each mu of nursery land. By early June, 8~ 10kg of available nitrogen fertilizer (such as urea) can be applied topdressing per mu in combination with watering, and urea can be applied topdressing in July ~ August (it is best to mix an appropriate amount of compound fertilizer 12~3 times, and the amount of fertilizer applied each time is about 30kg). Stop watering and fertilization after September to promote lignification of seedlings.
Fourth, plastic trimming. According to the need, it can be shaped and trimmed into three tree types: natural happy, cup-shaped and natural closed-axis trunk. Natural happiness refers to fixing the trunk when it is more than 3m long, selecting 3-4 branches with healthy growth and appropriate angles as the main branches, and removing the side branches and buds below the main branches in time. When cutting in winter, the main branches should be cut short and medium, leaving 50-60 cm to promote the growth of secondary branches and form small crowns; Cup-shaped, that is, keep three main branches like a natural heart, and cut two side branches from each main branch in winter to form six branchlets. In summer, the growth is controlled by coring, and two branches are cut off from each twig in the following winter to form a cup-shaped "three branches and six weights 12 branches". The trunk shape of natural combination means that after the main branches are retained, as long as the strong terminal buds and upright buds are retained in the future, pruning will be carried out to cultivate strong branches at all levels, so that the crown will continue to expand.