Acacia also known as cashmere tree, leguminous, deciduous trees, beautiful branches, beautiful cashmere flowers, rich aroma, long flowering period, is one of the excellent greening tree species in North China. However, during the breeding process of Acacia seedlings, the seedlings of Acacia seedlings often die and die due to improper management measures. In order to understand the law of Acacia seedlings and to solve the problem of dry and dry seedlings during the wintering period of Acacia seedlings, I investigated the causes and scientific experiments in practice and summarized the causes of the dryness of the Acacia seedlings during the wintering period and took corresponding measures and achieved ideal results. effect. The introduction is as follows for reference. 1. Acacia seedlings should be planted closely to ensure good individual development of seedlings. If the density is too high, it can easily cause severe canopy closure at the late stage of seedlings, resulting in insufficient photosynthesis of pressed seedlings, reduction of photosynthetic products, and insufficient accumulation of nutrients in dry phloem cells. Dry trails have a thin protective layer. After defoliation, a large amount of water flows back to the roots. The remaining water is small. Because the phloem cells are thin, the stomata are large, and the loss is severe, normal physiological needs cannot be maintained, resulting in cell necrosis and dry seedlings. According to the practice, 4,000 seedlings per year are 666.7 square meters, 1,500 seedlings are 666.7 square meters for two-year-old seedlings, and 800 per 666.7 square meters for three-year seedlings. The density is too small, which is not conducive to cultivating trunks. Second, topdressing nitrogen fertilizer in advance to promote early-onset seedlings In recent years, some nursery families have pursued the greatest profits. Often after August, they also applied topdressing nitrogen fertilizer, causing the seedlings of the seedlings to fall down. The cells at the tip of the seedlings are still in a large number of divisions. The growth of the shoots is long and the growth hormone concentration is too large, affecting the abscisic acid. In the formation, the stem cells of the stem diameter of the seedlings were thin, the stomata were not closed, and there was little accumulation of photosynthetic material. Under the condition that the leaves did not fall, they entered the winter, but only the cells in the formation layer became cold and the cells became necrotic. The correct top-dressing method is that when the annual seedlings are planted in May-July, they can apply 2-3 times of available nitrogen fertilizer. Before falling leaves, 2500 kg of quality circle fertilizers are applied, and 2-3 years of Albizia chinesis sprout to the end of July, respectively. For nitrogenous fertilizers, the dosage for each 666.7 square meters is 10 kg, 15 kg and 15 kg, respectively. In August, the application rate of compound fertilizer was 15 kg per 666.7 m2, prompting the seedlings to gradually decrease with the temperature, the high growth rate continued to slow down, the skin cells were thickened, and the growth of the seedlings changed from strong to strong and the cold resistance was strong. Third, the fall of the timely prevention and control of Acacia seedlings harm, Acacia seedlings fall susceptible to the harm of aphids, the insect purple brown or green brown, in the Acacia last year, the egg winter, in early August began hatching larvae, 2- After three days, the adult was changed rapidly, and the breeding was rapid, and the back of the leaf blade or the shoot was tendered. If the control was not timely, the density of the insect population was very large, the seedlings were seriously damaged, the seedlings were tainted, and many of them fell off. Photosynthesis was reduced, and the nutrient loss was serious. The accumulation of nutrients decreased, the tree vigor weakened, and the skin cells of the seedlings were poorly developed, and the ability to resist cold was poor. In the winter, the skin cells in the skin were prone to dehydration and death. Fourth, to avoid cultivating seedlings on low-viscosity, heavy soil, and reduce the damage caused by white jujube disease in the roots of Albizia julibrissin. Poor low-lying viscous and heavy water will cause poor water in the soil and cause soil hypoxia, which is beneficial to the roots of Albizia julibrissin. Occurs, spreads, and harms the roots of the seedlings, causing discoloration and rot in the cortex of the seedling roots and stem bases. White jujube-like mycelium and brown nucleus are found on the surface, resulting in the death of the whole plant. Control methods: 1. Choose a flat sandy soil with good drainage. 2, timely drainage after heavy rain, to avoid long-term accumulation of water, to prevent root oxygen deficiency. 3. Loose soil in time when the soil is compacted to increase soil permeability and ensure oxygen supply. 4. Apply 25 kg of ferrous sulfate every 666.7 square meters to disinfect the soil and reduce the incidence of pathogenic bacteria. 5, to predict the occurrence of the disease in time, if a small amount of leaves are found to be yellow, the tree vigor is weakened, the root can be inspected, and the germs are found to be infected. 500-800 times of the anti-virus liquid can be used to irrigate the root, or the individual plants can be The land is thoroughly cleared and destroyed to prevent further infection of the mycelium. In short, Albizia julibrissin seedlings must be based on the law of growth of Albizia julibrissin, rational close planting, scientific fertilization, and timely prevention and control of pests and diseases. According to the actual conditions of seedling growth, adopting the correct technical measures can effectively prevent and control the occurrence of overwintering seedlings withered and died. Good economic benefits. Urit Medical,Medical Analyzer,Medical Test Paper,Laboratory Analyzer Changchun Medicon Technology Development Co., Ltd , https://www.teststrip.pl