1 propagation method
1. 1 sowing and propagation
1. 1. 1 seed selection. The quality of cedar seeds will directly affect its germination rate. So we must choose fresh seeds, and the germination rate can be as high as 90%. At the same time, clear the empty grains.
1. 1.2 seed treatment. Before sowing, soak the seeds in potassium permanganate 1h, then rinse them, then soak them in warm water at 40℃ for 48 hours, and rinse them 1 time every day. Take them out to dry before sowing. Don't let the seeds contain water.
1. 1.3 site selection and soil preparation. Cedar is afraid of waterlogging and drought. It is best to plant in a place with low slope, good drainage and irrigation and flat terrain. The soil is preferably fertile and slightly acidic. When raising seedlings, it is best to use uncultivated plots instead of old nursery plots that have been planted for many years. Disinfect the soil before sowing, and mix the fine soil with carbendazim in proportion. If the soil is sticky, vermiculite, peat, sawdust or fine sand can be properly added to improve the water retention and air permeability of the soil. At the same time, the compound fertilizer and ferrous sulfate are evenly mixed, and the combination is turned into the seedbed.
1. 1.4 sowing. The best sowing date is in March or April, and the sowing amount is not more than 75kg/hm2. Because cedar seeds are not easy to obtain, the sowing method should be as far as possible, that is, the big head of the seeds is up, the spacing between plants is about 5cm, the row spacing is 15cm, and the covering thickness is less than 1cm[ 1]. Immediately after covering the soil, it should be compacted, covered with straw curtains and watered in time. When the seeds are unearthed after 2~3 weeks, remove the straw curtain, build a shade shed and water them in time to ensure the soil is moist. Topdressing can be carried out two weeks after the seeds are unearthed, and it is best to use natural fertilizers or quick-acting fertilizers and apply them in furrows between rows. After the seedlings grow up, loosen the soil in time, not too deep; In order to avoid soil hardening, loosen the soil immediately after rain.
1.2 cutting propagation
1.2. 1 cuttings collection. The age of mother tree is directly related to the survival rate of cutting. The younger the mother tree, the stronger its vitality, and the survival rate of cutting will also increase. Therefore, it is best to choose strong mother branches less than 5 years old as cuttings, the length of which is about 15cm, which is easy to take root. Collect cuttings in July and August, because the seedlings grow slowly at this stage, it is best to collect cuttings in the morning or evening, and ensure the freshness of cuttings during the collection process. Cut, cut, cut. In order to carry out photosynthesis better, some needles or spikes should be reserved.
1.2.2 cutting. Cedar can be cut all year round, but the main cutting season is spring, and the time is around April. Soil disinfection should be carried out before cutting in spring. When cutting, ditch first, then irrigate, and insert the cuttings into the seedbed to make the soil closely contact with the cuttings. The plant spacing is 5cm× 10cm, and the cutting depth is 8~ 10cm. If the oblique cutting method is adopted, the depth is 6~8cm. Water and shade in time after cutting (the best light transmittance is 30%~40%), which can effectively prevent water evaporation and avoid cutting wilting.
Post-planting management
2. 1 water and fertilizer management
After sowing, in order to ensure soil moisture, it should be watered immediately. Due to the high air humidity and low temperature in the early stage of sowing, it is necessary to cover the film in time, which is beneficial to improve the germination rate and ensure the orderly germination of cedar plants. Cutting propagation, if the water is insufficient, the survival rate of cuttings will be reduced due to water loss; Too much water, cuttings are easy to rot, and will also affect the survival rate of seedlings. Therefore, foliar spraying can maintain water balance and improve the survival rate. When the temperature is high in summer, it is necessary to increase the frequency of spraying water, which can not only maintain soil moisture, but also reduce the surrounding temperature and help cuttings take root. Tillage, weeding and irrigation can be carried out before topdressing, and potassium dihydrogen phosphate solution or foliar spraying can be used for comprehensive topdressing; During the fast-growing period of seedlings, urea was applied at an interval of 2-3 weeks, ranging from 37.5 kg/hm2 to 45.0 kg/hm2.
2.2 Cold and cool
Cedar is a positive tree species, which likes light and has strong shade tolerance. If the growth conditions are insufficient, it is easy to grow badly. The stage with the strongest shade tolerance is seedling stage, and it likes cool weather. The suitable annual rainfall is 600~ 1200mm, and the minimum temperature of shade tolerance is 25℃. It is best to plant it in the leeward. Cedar seedlings should be cold and warm in winter and protected from the sun and shade in summer. The most suitable environment for seedling growth is the area with weak light. If the light is too strong or exposed to the scorching sun, the leaves are more likely to be burned and even lead to plant death. Therefore, growers need to build a shed to shade the seedlings, the height of the shed should be above 1m, the light transmittance is 50%, and manual maintenance should be carried out regularly. Shading shed should be protected from cold in winter and light in summer, which is beneficial to the healthy growth of cedar seedlings.
2.3 Soil support
By reasonable pruning and cutting off the overlapping branches and leaves of the trunk, the number of branches and leaves can be reduced, and the ratio of root to shoot can be adjusted to a suitable ratio, which can not only improve the survival rate of seedlings, but also be beneficial to the cultivation of trees. Some cedars have few roots, large crown and serious imbalance in root-shoot ratio. If there is little rain in spring, with the increase of evaporation, the survival rate of plants will be greatly reduced. Therefore, if the local soil properties are not good and the seedlings have few roots, growers need to cultivate and support the soil. The root of cedar is cultivated with soil, about 40cm away from the plant, and then fixed with rope or iron wire. The number of ropes or iron wires for each cedar is 3-4, the cable-stayed fixed angle is about 120, and the height is 150cm. Soil-raising scaffold can effectively improve the growth quality of cedar plants.
2.4 Pest control
At the same time of fertilizer and water management, weeding should be done in time during intertillage to strengthen the defense of pests and diseases. Cedar pests are mostly cutworms and grubs, which can be trapped and killed by sweet and sour liquid and black light. When larvae harm the roots of plants, they can be killed with poison bait; Most of the pests on the aboveground part of seedlings are cutworms, which can be controlled by spraying 20% trichlorfon powder. Serious damping-off can occur in the late growth stage of cedar, which can be prevented by spraying carbendazim wettable powder1:1:100. In daily management, proper water control and enhanced illumination can not only improve the survival rate of seedlings, but also prevent pests and diseases.