What kind of eucalyptus seedlings?

What kind of eucalyptus seedlings? Please give a detailed introduction to guide eucalyptus seedling breeding can refer to the following methods: 1, seedling cultivation 1.1 seedbed preparation (1) seedbed specification bed width 1.2m, length generally less than 5m, trail width 5cm. (2) after shoveling the weeds and topsoil from the border, spray 25% trichlorfon oil 50-100g (active ingredient) or use fried rice as poison bait on the seedbed, especially the latter can effectively trap ground tigers, mole crickets and other underground pests. Then, lay a layer of yellow clay soil about 5cm thickness, and then lay a layer of seedling substrate about 1Ocm thickness (the substrate is screened with a sieve hole of 4mm diameter). The proportion of each component of seedling substrate was yellow mud core soil 4: burning soil 6, and 11kg compound fertilizer / m ~ 3 was added. It can also appropriately reduce the proportion of yellow mud core soil and burning soil with the right amount of river sand. (3) 40% formalin or 15OO*l0-6 topazine solution for soil disinfection was sprinkled through the seedling bed, and then methyl isosinophos was mixed with fine sand (usually 20% EC 300-400ml to make toxic sand 20-30kg, note that this product is the main toxic insecticide) evenly scattered on the seedbed, and then covered with film for at least 24 hours. It can play the role of soil sterilization and killing underground pests again. (4) after the above treatment, after 1-2 days of sun exposure and ventilation, the flat seedling bed can be scraped, drenched with water, and then evenly spread a thin layer of burning soil, scraped flat, and compacted with a plank. Wet the seedling bed with a sprayer before sowing, and sow seeds after leveling. 1.2 sowing time (1) sowing time combined with the weather conditions of the province and the practical experience of the Bureau for many years, sowing should be carried out in mid-late October, because the weather is still warm during this period, which is conducive to eucalyptus seed germination and seedling growth. The seedlings can come out of the nursery after 3.5-4.5 months, which coincides with the afforestation time of the following year in January-February. If the afforestation area is large, it can be sown in batches so as to facilitate the arrangement of labor during afforestation. (2) the sowing rate can be determined according to the following empirical formula: sowing amount = (2-3) x afforestation area (hm2) x afforestation density (plant / hm2) x seed number / g generally 2000-3000 seeds per square meter, so when preparing the seedbed, the seedbed area can be determined accordingly. (3) when sowing and sowing, each gram of seeds should be sterilized with 0.1-0.2g carbendazim or thiophanate-methyl, thiophanate, dimethazone and other pesticides, then add 20-30 times of sifted clean burning soil to mix well and spread. After sowing, the soil is covered evenly with fire, so that the seeds are not seen. After that, sprinkle the running water with a sprayer. Then covered with film insulation, the film vault is 45cm higher than the bed surface, in order to facilitate ventilation and ventilation. After the sowing work was completed, the solution of methyl isofenphos was sprayed around the nursery and the concentration was the same as that of soil disinfection. 1.3 during germination period, the optimum germination temperature of eucalyptus seeds is 25Mu35 degrees, and the relative humidity is 85% and 95%. If the temperature exceeds 35 degrees, open the two ends of the nursery bed in time for ventilation or sprinkle water on the film to cool down. For example, 50% shade net is used to cover the shade when continuous high temperature and long sunshine time. Eucalyptus seeds have been basically unearthed for 15 days to complete the germination process. During this period, the seedling bed must be kept moist, water should be drenched once in the morning and evening, and sprays should be used when water is drenched. Use it until 50% of the seedlings grow a true leaf. 1.4 the management of seedling stage is the seedling stage from seed germination to before the seedling is bagged, which is mainly the growth and development of root system. The key is the management of soil moisture, the over-dry root system is short of water and grows poorly, and too wet is easy to cause root disease. Generally, you can be drenched with water once in the morning and evening, only once in cloudy and rainy days, or every other day or 2-3 days according to the situation. The duration of seedling stage varies with different varieties, generally about 45 days. In case of sunny day, the film must be opened between 10:00 and 16: 00:00. With the further increase of sunlight, 50% shading net should be used to protect the seedlings from burns. The requirement for fertilizer in the small seedling stage is not high, so you can properly spray 1-2 times of quick-acting nitrogen fertilizer, such as urea, which should also be dilute rather than concentrated, and it is best to wash the seedlings with clean water after fertilizing, so as to prevent the young leaves from being burned by fertilizer. 2, the seedlings generally grow new roots in about a week after transplanting. If there is no frost at this time, the film can be opened. If the temperature is low and there is frost, the covering time should be extended. If a dead seedling is found in the film, it should be replenished in time. (1) after transplanting the seedlings into the bag, the water and fertilizer management should be watered once a day in the morning or evening to keep the container matrix moist. As mentioned above, the management of big seedlings is mainly to have sufficient fertilizer, basically fertilizing once a week, mainly nitrogen fertilizer, generally applying liquid nitrogen (urea) with a concentration of 2%, 5% liquid nitrogen (urea), in order to make the bag as high as 15-25cm after 50 days, you can go up the mountain for afforestation. If the growth is exuberant, water and fertilizer should be controlled. (2) Seedling grading when the seedlings are transplanted into the bag for one month, due to the influence of the microenvironment and the genetic differences among the seedlings themselves, the seedlings have shown differentiation between height and thickness, so they should be graded in time to facilitate future management. And provide uniform seedlings for afforestation up the mountain. (3) Seedling height control due to weather or other reasons. In the afforestation season, the seedling height can reach 30cm, but can not go up the mountain for afforestation. Measures should be taken to control the seedling height. Besides water and fertilizer control, the overgrowth of seedlings can also be controlled by moving seedlings and spraying trace PP333. When the seedling height reached 20~25cm, the root system of the seedling basically penetrated the bag. At this time, the bag should be moved in time to cut off the root, on the one hand, to prevent the main root from going into the ground, resulting in the excessive growth of seedlings; on the other hand, it can promote the development of fibrous root in the bag and cultivate seedlings with developed roots for afforestation. In the process of moving the bag, do not loosen the nutrient matrix, so as not to affect the survival. The bag should be drenched with water before moving, and then drenched again after removal. The seedlings should be moved in the morning and evening when the sun is strong in sunny days, but not in rainy days. If the weather can not go up the mountain for afforestation, the seedlings should be moved every 10 days until they can go up for afforestation. When the seedling height reaches 30cm, in the near future, those who can go up the mountain for afforestation, it is necessary to control their overgrowth, generally using 15%PP333 (50mur100) X10-6 spray, the effect is ideal. In addition, some people use the method of cutting the top to control its height growth. However, for the timber forest, we think it is worth being cautious to cut off the top advantage. Click to get more eucalyptus planting techniques click to get more flower planting techniques