Seedling raising techniques of sycamore in North China

Chinese parasol tree, also known as Firmia simplex, is a deciduous tree belonging to the genus Sterculiaceae. Its crown is oval, its trunk is straight and upright, its bark is bright green and smooth, its leaves are dense and shady, its adaptability is strong, and it grows rapidly. It is mostly planted as street trees and courtyards. At present, it is recognized by more and more people and has high promotion value and good market prospects. Now the Chinese parasol seeding seedling technology is introduced as follows.

1. Seed collection and preparation

Select 15~30-year-old mother trees with strong growth, straight stem shape and no diseases and insect pests for seed collection. Wutong seeds mature from late September to early October, with yellow wrinkled pericarp. The seeds are cracked before maturity, and the seeds are easy to scatter. They should be collected together with fruit stalks in time. After collecting seeds, spread them out and dry them, turn them 2~3 times a day, rub off the pericarp, and store them in dry or sand after removing impurities. As the seed coat of Chinese parasol thin, easy to lose water and dry and lose germination, to sand storage is good. 1000-seed weight is about 125g, germination rate is 85%~90%.

2 Selection and treatment of nursery land

2.1 Selection of nursery land

Choose soil layer deep, loose, rich in humus, good drainage soil, in acid, neutral and calcareous soil can grow, but should not be planted in stagnant depression or saline land. The roots are easy to rot after ponding, and they can die after 5 days of waterlogging.

2.2 Disinfection and herbicide spraying of nursery land

In order to prevent the damage of diseases and insects in seedling stage, soil disinfection can be carried out by applying 70% dixon powder 1~2kg/667m2 mixed with 50 times fine soil and evenly spreading it to prevent seedling diseases. At the same time, 3% carbofuran granules 1.5~2.5kg or phoxim 0.125%~0.2% solution mixed with soil can be sprayed to control underground pests. The Chinese parasol tree is not tolerant to grass shortage, so chemical weeding can be carried out 20 days before sowing. Available 50% acetochlor per 667m2 dosage 50mL mixed with 50kg water, uniform spray, valid for about 2 months.

2.3 soil preparation bed

In early winter, the nursery land can be deeply ploughed 30cm, broken into pieces to make it granular, and 1000kg of decomposed organic fertilizer can be applied per 667m2. Bed width 100cm, height 20cm, footpath width 40cm, length anywhere, dig drainage ditch around, so as to ensure that there is no ponding in the ditch when rain stops.

3 Disinfection and germination of seeds

The seeds are selected 30~40 days before sowing, and the seeds with sound development, fullness, large grain size and no diseases and insect pests are selected. Then the seeds are disinfected. The seeds can be soaked in 0.5% potassium permanganate solution for 2h(or 3% potassium permanganate solution for 30min), taken out and sealed for 30min, and washed with clean water for several times. Finally, soaking seeds in warm water for germination, soaking seeds in warm water at 60 - 80 DEG C (the water surface submerges the seeds for more than 10cm), taking out the mixed wet sand pile 20 - 30cm thick after 24 hours, covering with wet sacks or wet straw, placing in leeward sunny place for germination, watering 2 - 3 times a day, and sowing when more than 30% of the seeds have cracked mouths.

4 Sowing and covering

After spring soil thawing, it is carried out from late March to early April. The row spacing is 25cm, the seeding rate is about 15kg/667m2, the seeding should be uniform, and the soil should be covered at the same time. The thickness of soil covering is 1.0~1.5cm, and the thickness should be uniform to facilitate the emergence of neat seedlings. After sowing, cover with a layer of straw (preferably invisible to the ground) to keep the soil moist and unearthed for about three weeks.

5. Thinning of grass

When about 30% of cotyledons emerge after germination, the covering grass can be removed. When the seedling height is about 5 cm, the first seedling inquiry is carried out, when the seedling height is about 10cm, the second seedling thinning is carried out, the plant spacing is 20 - 30cm, and weeds are pulled out at the same time.

6 Fertilizer and water management

Different periods, different management measures, irrigation and fertilization should be adapted to local conditions.

6.1 irrigation

After sowing to the early stage of seedling growth, small water should be irrigated frequently to keep the soil moist, so as to facilitate the germination of seeds and the growth of seedling roots; in early July, seedlings enter the fast-growing period, increase the amount of irrigation, so as to achieve more and less times, and maintain the water balance of seedlings; in mid and late September, the high growth stops, and irrigation should be stopped to prevent the seedlings from not lignifying enough and affecting the safe winter.

6.2 Shi Yueba

After the emergence of true leaves, ammonium sulfate or ammonium bicarbonate can be applied at a rate of 30~35kg/667m2, divided into three times; phosphorus fertilizer is applied at a rate of 2.5~ 2.8 kg/667m2, with a concentration of about 0.7%~1.5%; potassium fertilizer is applied at a rate of 2 kg/667m2, with a concentration of about 0.5%. Generally spray 2 - 3 times. After September, in order to prevent excessive growth of seedlings, it is necessary to stop applying nitrogen fertilizer and increase phosphorus and potassium fertilizer to enrich seedlings and facilitate overwintering.

7. Cultivation of large seedlings

In the first two years after planting, we should often loosen the soil and weed, strengthen fertilizer and water management, pay attention to protecting young trees, and do not damage and trim the top of branches to avoid withering and destroying the tree shape.

8 Pest control

8.1 Psyllid parasol

Its nymph and adult gather on the back of leaves or young branches to suck. The white waxy floc secreted by nymph can block stomata, causing pale and atrophied leaves. At the same time, it is easy to cause mold parasitism. In severe cases, leaves fall early, branches dry, epidermis is rough and fragile, and it is easy to be broken by wind. Insect pests can be sprayed with 25% trichlorfon, marathon 800 times solution or 40% dimethoate 2000 times solution or 80% dichlorvos EC 1000~1500 times solution.

8.2 eucleidae

Larvae feed on the lower epidermis and mesophyll of leaves, and eat up leaves seriously, leaving only veins and petioles, which seriously affects plant growth. In winter, you can pick the cocoon or break the cocoon on the trunk to reduce the source of insects. 40% phoxim emulsifiable concentrate 1000 times solution, 45% beta-cypermethrin 1500 times solution and 20% luan 1000~1500 times solution shall be sprayed evenly in time during pest occurrence period.

9 winter cold

Winter to young trees to package grass cold, if conditions permit, every year before winter and early spring each fertilization, irrigation once.