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Greenhouse seedlings
The use of plastic greenhouses to cultivate tree seedlings can not only improve the quality of seedlings, speed up the growth of seedlings, shorten the seedling-raising cycle, but also increase the amount of seedlings per unit area and improve the land utilization rate. First, the planning of seedling nursery land in order to facilitate the operation and management of the principle of content, including roads, drainage, irrigation canal, seedbed configuration, etc., to minimize non-productive area, improve the utilization of land within the shed. The main road should be set along the long side of the shed and the secondary road should be perpendicular to the main road. The width of the main road is 50-60 cm, and the width of the auxiliary road is 30-40 cm. Rows and irrigation channels can be combined with road planning. Low bed operation is generally used in the shed. The trail is 10 to 15 cm above the bed surface. The direction of the seed bed is perpendicular to the main road. The bed width is 1 to 1.2 meters, and the length of the bed depends on the width of the shed. If sprinkler irrigation equipment is used, the layout of pipes should facilitate the operation of the nursery. Second, before the preparation of seedlings First, in accordance with the plan to build a bed, soil preparation, when applied to the base fertilizer, and soil disinfection, the soil crush and stir, flatten the bed. The use of container seedlings for coniferous seedlings is beneficial to the cultivation of good quality seedlings, and can also increase the utilization rate of greenhouses. Choose a container cup with a quality that is not easily damaged. The choice of nutritious soil depends on the seedling variety. The container filled with nutritious soil was neatly discharged into the nursery bed. Third, the sowing and seeding technology varies depending on the species. Take the Chinese pine as an example to introduce the following. The date of sowing depends on the number of planned nurseries. The spring can be planted in early March, autumn sowing in late September to early October, and can be cultivated twice a year. Before sowing the seed bed should be filled with bottom water, and then sprinkle water on the container cup with a watering can, moisten the cup of soil 2 ~ 3 cm deep is appropriate. Seeds should be disinfected and germinated prior to sowing, until 70% to 80% of the seed splits can be sowed. Each cup is broadcasted with 3 to 4 capsules, and the cover soil is 1 cm thick. The water is then sprayed with a watering can and the amount of water is moistened with the skin. If the seedlings are planted directly on the seedbed, they must be thoroughly immersed in the bottom water. Before sowing, loosen the soil, drill and sow seedlings, sow about 50 grains per metre, and cover the soil 1 to 1.5 centimeters thick. IV. Post-broadcasting management 1. Temperature control The optimum temperature for the growth of seedlings in the shed is 25°C to 30°C, and the temperature must be controlled artificially. In the late autumn and early winter, the focus is on warming and heat preservation, paying attention to the confinement of greenhouses, reducing the area and frequency of ventilation, and covering grass curtains outside the greenhouse during the night. Cloudy grass can not be rolled during the day. In the late winter and early spring (from late April to early May), the temperature rises slightly, and the temperature difference between days is relatively large. It can be ventilated at the highest temperature in the afternoon. After mid-May, the temperature outside the shed increased, and the temperature in the shed increased. The temperature was between 22°C and 30°C throughout the day. When the temperature in the shed rises to 30°C, cooling measures must be taken. The method is spraying, spraying water, cooling water, opening doors and windows, rolling up the bottom plastic, and implementing a large area of ​​ventilation. When the temperature reaches 35°C, all the shed film should be removed, and shading can be used to shade it when necessary. 2. Moisture management container Seedlings should be sprinkled with water according to the circumstance. Seedlings of P. tabulaeformis are sprinkled once every 1 to 2 days, and should not be excessively humid. In order to reduce temperature and increase humidity, water is sprayed on seedbeds and roads at the same time. 3. Ventilation When the air temperature outside the shelter is lower than 10°C, close the louvers at night and open the doors and windows in the morning for ventilation. When the temperature outside the shed reaches 20°C to 25°C, the doors and windows are opened at night and all the side windows and skylights are opened during the day. When the temperature rises to 30°C, the surrounding film is rolled up to a height of 1 meter. When the temperature drops to 20°C in the afternoon, the film is put down and part of the louvers are closed. In June, all shed films will be removed. In windy weather, all ventilation windows and doors and windows in the greenhouse should be closed to prevent the wind from tearing the film. 4. The soil management should be top-dressed in a timely manner and then combined with top-dressing. In the early stage, nitrogen and phosphorus fertilizers were the main components, and phosphorus and potassium fertilizers were the main components in the later stage. Each growth cycle is applied 5 to 6 times. The container seedlings are manually weeded once every 10 to 15 days, and the bed seedlings can be weeded with a small amount of loose soil. 5. Diseases and Insect Pests Controlling the coniferous tree seedlings is mainly blight. Adhere to prevention, strict seed and soil disinfection, pay attention to ventilation, spring sowing should not be too late. As long as these links are taken care of, we can basically prevent the occurrence and spread of blight. When the temperature is high, the temperature is lowered, ventilation is enhanced, and blight does not occur. Production practices have shown that chemical agents are not as effective as controlling temperature and humidity in the shed and strengthening ventilation and ventilation. 6. Withdraw sheds and keep seedlings in order to enhance the resistance of seedlings in the shed and adapt to the external environment. It is necessary to timely withdraw the shed and pay attention to the process of hardening the seedlings before the shed. That is, first remove the 1/4 to 1/2 of the upper film, and then gradually withdraw the film. The premature withdrawal of the film has adversely affected the growth of the seedlings and even resulted in the death of the seedlings.