Albizia julibrissin, also known as velvet tree, is a deciduous tree in the Fabaceae family and is a common street tree. It has strong adaptability to climate and soil. It likes sunshine but is intolerant of shade. The suitable growth temperature is 13~18℃. It can withstand low temperatures of -10℃ in winter. It is not tolerant to severe cold and waterlogging. Therefore, during the cultivation of Albizia julibriss seedlings, especially in winter, it is often As a result, Albizia julibrissin seedlings have difficulty overwintering, and a large number of seedlings dry up and die in winter. Based on many years of maintenance experience, the following will introduce to you the methods to prevent the overwintering seedlings of Albizia julibrissin seedlings from drying out and dying, for your reference and learning.

1. Reasonable dense planting

Albizia julibrissin seedlings should be planted reasonably densely to ensure good individual development of the seedlings. If the density is too high, it will easily cause serious canopy closure of the seedlings in the later stage, resulting in insufficient light for the suppressed seedlings. , the photosynthetic products are reduced, the phloem cells in the dry diameter have insufficient accumulation of water and nutrients, and the protective layer in the dry diameter is thin. After the leaves fall, a large amount of water flows back to the roots, leaving little remaining water. Because the phloem cell layer is thin, the pores are large, and the pores are large, the loss is serious, and normal physiology cannot be maintained. Needed, causing cell necrosis and seedlings drying up. According to practice, it is appropriate to have 4,000 annual seedlings per 666.7 square meters, 1,500 biennial seedlings per 666.7 square meters, and 800 three-year seedlings per 666.7 square meters. The density is too small, which is not conducive to cultivating the main trunk.

2. Apply nitrogen fertilizer in advance to promote early growth of seedlings

In recent years, some nursery households, in pursuit of maximum profits, often apply nitrogen fertilizer after August, causing frost on the saplings. The cells in the front shoots are still growing in large numbers, the new shoots are growing vigorously, the auxin concentration is too high, which affects the formation of abscisic acid, the stem diameter of the seedlings is thin, the phloem cells are thin, the stomata are not closed, and there are few photosynthetic substances accumulated, and the leaves have not fallen. When winter comes, the water in cambium cells freezes when exposed to cold, causing cell necrosis. The correct topdressing method is to topdress the current-year seedlings with quick-acting nitrogen fertilizer 2-3 times from May to July, topdress 2,500 kilograms of high-quality fertilizer before falling leaves, and topdress 2-3-year-old Albizia julibrissin seedlings 3 times from May to July after germination. The dosage of subnitrogen fertilizer per 666.7 square meters is 10 kilograms, 15 kilograms, and 15 kilograms respectively. Topdressing 15 kilograms of compound fertilizer per 666.7 square meters in August will cause the seedlings to slow down as the temperature gradually decreases. The skin cells will thicken, and the seedlings will grow from vigorous to strong and have strong cold resistance.

3. Timely prevention and control of insect pests in autumn

Albizia julibrissin seedlings are prone to damage from alfalfa aphids in autumn. The insects are purple-brown or green-brown, one generation above Albizia julibrissin, and overwinter with eggs. They begin to hatch into larvae in the first ten days of the month and transform into adults in 2-3 days. They reproduce rapidly and pierce and suck the backs of leaves or young shoots of petioles. If the prevention and control is not timely, it is easy to cause a large density of insects, serious damage to seedlings, and the damaged seedlings will be stained and fall off in large quantities. , photosynthesis is reduced, nutrient loss is serious, nutrient accumulation is reduced, tree vigor is weakened, the bark cells of the seedlings are underdeveloped, and their cold resistance is poor. In winter, the bark cells are easy to lose water and dry up and die. When insect pests are discovered, aphid or forest insect net should be sprayed promptly to effectively control them, so as to eliminate their harm to Albizia Julibrissin seedlings.

4. Avoid raising seedlings in low-lying areas

Avoid raising Albizia julibrissin seedlings on low-lying, heavy soil to reduce the harm of white silk disease on the roots of Albizia julibrissin. Low-lying, heavy soil has poor drainage and is prone to rain. Accumulation of water causes soil hypoxia, which is conducive to the occurrence and spread of white silk disease on the roots of Albizia julibrissin seedlings, harming the roots of the seedlings, causing the cortex of the seedling roots and stem bases to become discolored and rotten, with white silky hyphae and small brown sclerotia on the surface, causing overall The strain dies.

According to the biological characteristics of Albizia julibrissin seedlings and the growth conditions of the seedlings, effective preventive measures should be taken to reduce the drying out and death of seedlings in winter.