After the seedlings are unearthed, someone should be assigned to look after these birds. When the seedlings are all out, spray them immediately. 5%- 1% bordeaux mixture and then spraying 1 time every 7- 10 days for 3-4 times in a row can prevent the occurrence of damping-off disease.
Irrigation should be properly controlled during seedling growth period to promote root growth and development. The fast-growing period of seedlings is just in the high temperature and drought period after the middle and late June and before the rainy season. The temperature is high and the rainfall is low. It is necessary to irrigate in time and increase the irrigation times appropriately, and the irrigation amount will gradually increase. According to the soil moisture content, it needs to be irrigated once every 10- 15 days. Based on the principle of once irrigation, it is appropriate to use sprinkler irrigation or side irrigation. After entering the rainy season, reduce irrigation, pay attention to drainage and flood control, so that internal water does not accumulate and external water does not invade.
Topdressing and irrigation are combined in the fast-growing stage of seedlings. Ammonium sulfate is usually topdressing 2-3 times a year, with 4-6 kilograms of ammonium sulfate per mu, at the early stage of fast-growing seedlings 1 time, and topdressing again after half a month. You can also use decomposed human feces for topdressing. After each topdressing, it must be watered and washed in time to prevent seedlings from burning.
Platycladus orientalis can bear some shade at seedling stage, so it should be planted closely. When the seedlings get too close to affect the growth, it is time to remove the weak seedlings, the pests and diseases seedlings and the double seedlings. Generally, when the height of seedlings is 3 ~ 5 cm, the seedlings are thinned twice. After the seedlings are fixed, the amount of seedlings per square meter is about 150, and the yield of seedlings per mu can reach1500,000.
Weed and loosen the soil in time during the seedling growth period to achieve "early weeding, small weeding and large weeding". At present, chemical agents are mostly used for weeding, using 35% herbicide ether (EC), 2 ml per square meter, diluted with water and sprayed. Spraying 1 time after sowing or before emergence, spraying for the second time after 25 days and spraying continuously for 2 ~ 3 times can basically eliminate weeds. The dosage per mu is 0.8 kg each time. When the hardening of topsoil affects the growth of seedlings, loosen the soil in time, and the depth of loosening soil is about 1 ~ 2 cm, which should be carried out after rainfall or watering, and be careful not to touch the root system of seedlings.
The seedlings of Platycladus orientalis should be well protected against cold in winter. In cold and windy areas in winter, generally, frozen water is poured before the soil freezes, and then the soil is covered for cold protection or the wind wall is sandwiched for cold protection, or grass can be covered for cold protection. Production practice shows that covering soil has the best cold-proof effect, which is not only simple and labor-saving, but also beneficial to the safe overwintering of seedlings. However, it should be noted that the time of burying soil for cold protection should not be too early, and it is generally appropriate before and after beginning of winter before soil freezing; It is not too late to remove the cold-proof soil, and it is usually removed twice before and after Qingming after thawing; After moving the soil, make up the green water in time to prevent the seedlings from losing water and turning yellow due to the strong spring drought and wind.
Platycladus orientalis seedlings leave the nursery for two years and are transplanted in the spring of the following year. Sometimes in order to cultivate green seedlings, it is necessary to transplant them 2-3 times to cultivate large seedlings with developed roots, strong growth and beautiful crown, and then plant them in the garden. According to local experience, the survival rate of transplantation in March-April in early spring is relatively high, generally reaching more than 95%.
The transplant density depends on the culture cycle. Seedling raising after transplanting 1 year, plant spacing10cm× 20cm; Cultivation for 2 years, row spacing of 20 cm ×40 cm; Cultivation for 3 years, row spacing of 30 cm× 40 cm; To cultivate large seedlings over 5 years old, the row spacing is1.5m× 2.0m. Generally, it needs to be transplanted for many times to cultivate large seedlings, which is not only conducive to promoting the growth and development of seedling roots, but also to cultivate good crown shape and dry shape, and can improve the land utilization rate.
According to the size of seedlings, different transplanting methods are adopted, such as narrow slot transplanting, ditching transplanting and digging transplanting.
The management of seedlings after transplanting is mainly to irrigate them in time and thoroughly every time. When the soil moisture is suitable, timely adopt tending measures such as intertillage, weeding and topdressing. Except for shaping and pruning according to the requirements of landscaping, other measures are basically the same as those of general conifer seedling raising.