Before sowing, expose the seeds to the sun for 2-3 days, then soak them in hot water at 60-70℃, blanch them properly to soften the peel, rub them, and wash the pulp with clear water. Another method is to soak in 0.5% potassium permanganate solution for 2~3 minutes before sowing, and then rinse with clear water.
Sowing ground should be well drained and flat. Before sowing, the nursery should be leveled, ridged and broken. The sowing period is from late March to early April, the sowing amount is 20-30g/m2, the row spacing is 20-25cm, and the ditch depth is 3-5cm. After sowing, cover the soil and press lightly. Plastic film mulching can be used when conditions permit, and seedlings will emerge 10~ 15 days after sowing. Neem tree has 4~6 seeds in each hole, which are clustered after emergence. When the seedlings grow to 5~ 10cm, set the seedlings according to the spacing of 15cm, and leave 1 strong seedlings in each cluster.
cutting
Every year in late February or early March, seedlings or branches with a diameter of 0.5cm are selected and cut into cuttings with a length of 15cm before cutting. The upper opening of the cut is flat and the lower opening is inclined. Cutting spacing1.5 ~ 20cm, row spacing 30 ~ 40cm, depth 1/3 length. After cutting, the surrounding soil is compacted. In early April, adventitious buds on cuttings germinated and unearthed one after another. When the seedling grows to 5~8cm, only 1 tiller is left, which is cultivated into a seedling stem, and the rest tillers are erased. Water and fertilizer management
Timely irrigation: Different seedling raising methods need different irrigation methods. Nursery seedlings should be watered after sowing and covered with plastic film to keep the soil temperature, which is generally not needed. After the plastic film is removed, water it moderately according to the drought situation in the nursery, so that it will be wet when it is dry. The seedlings in the nutrition bowl have no cover and the water evaporates quickly. Spray water once every morning and evening, and spray a small amount of water frequently. Spray more in hot season, less or no in rainy day, and avoid spraying water in hot noon.
Rational topdressing: Rational topdressing is the basis of cultivating big and strong seedlings, and the topdressing at seedling stage should be based on base fertilizer. In order to make the seedlings grow healthily, topdressing should be added during the seedling growth period. Topdressing is mainly quick-acting fertilizer, so it is necessary to master the principle of topdressing in stages and skillful application of seedlings, that is, to control the types and dosage of fertilizers according to the needs of different nutrient elements in different growth stages of seedlings. At seedling stage, nitrogen fertilizer and phosphorus fertilizer should be mainly applied to promote the root growth of seedlings. Nitrogen, phosphorus and potassium should be properly coordinated during the fast-growing period of seedlings. Because the seedlings grow fastest in this period and need fertilizer and water most, it is necessary to strengthen loosening soil and weeding. During the hardening of seedlings, potassium fertilizer should be given priority to and nitrogen fertilizer should be stopped.
Winter management
For newly planted young trees, measures should be taken to prevent freezing and keep warm in the first three winters, such as rooting, tying branches with straw ropes or building windbreaks.
Plastic trimming
The terminal buds of Melia azedarach can not develop normally, so that the trunk of seedlings tends to bend and the branches are low. Trunk can be cultivated by changing stems or cutting tips and smearing buds. Dry-reform method is to cut young trees planted 1~2 years before germination in early spring, and the height of the cut trunk is about 10cm from the ground. After sprouting, select 1 stout sprouting branches to cultivate the trunk. Shoot-cutting and bud-wiping method is to cut off the tip of 1/3~ 1/2 with a sharp knife and cut off the upper part of the main tip of young trees with an inclined plane before germination in early spring 2~3 years. After sprouting new branches, select 1 stout new branches near the incision to cultivate the trunk, and the rest buds are erased. The next year, the immature parts of the new shoots were cut off in the same way. Dead branches, pests and diseases should be cut off every year after defoliation or before germination in early spring. The pests of Melia azedarach include the larvae of Melia azedarach and Melia azedarach, and the leaf-eating larvae of Chrysopa japonica.
The disease of neem seedlings is mainly damping off, so we should always pay attention to the prevention and control of this disease during the whole seedling raising process. The commonly used methods are treating nursery soil with 50% chlorpheniramine at a dosage of 35g/m2；; Treating seeds with 0. 1%-0. 15% wettable powder solution; Spraying 0.067% 50% benomyl solution at seedling stage; Spraying 0.33% 72% agricultural streptomycin sulfate solution at seedling stage. The prevention and control of rice sheath blight should master the principles of early treatment, small treatment and treatment, and the incidence of seedling raising in nursery land should be controlled within 15%, and the seedling raising in nutrition pot should be controlled within 10%.
The main pests of neem seedlings are grubs and grubs, which can be mixed with wheat bran with 50% parathion EC before seedling raising and scattered on the seedbed.