Rotten seed Under normal circumstances, no seedlings emerged 7 days after sowing, indicating that the seeds had rotted. In order to prevent rotten seedlings in the process of raising seedlings, sowing should be done in sunny and warm weather, using electric hot-bed or hot-breeding hotbeds to raise seedlings and thickening the cover to increase seedbed temperature. Freezing and cold damage Freezing damage refers to damage to plants caused by an ambient temperature below 0°C. Such damage is often devastating. Cold injury refers to the fact that in the absence of freezing, the ambient temperature is lower than the minimum temperature that the plant can tolerate, and the seedling growth is hindered. Measures to prevent cold injury and cold damage: First, artificially controlled temperature seedlings such as electric hotbeds are used. The second is to use the coal stove heating, plumbing heating, etc. to warm the greenhouse. The third is the use of multi-layer covering insulation, such as covering the film, deducting a small shed, cover straw and so on. The fourth is to strengthen the ventilation and hardening of seedlings, and increase the application of phosphorus and potassium fertilizers in seedbeds to improve the cold resistance of seedlings. The fifth is cultivator, which enhances the ability to absorb heat in the soil. Flood prevention root Roots are mainly caused by high humidity and low temperature. Prevention measures include: (1) Select a well-perforated soil as a seedbed and try to increase the temperature. (2) Control watering. When the seedbed is dry, the on-demand water is divided into pieces to prevent flooding. The ground does not turn white without water, and rainy days do not water. Once roots occur, they must be promptly ventilated and drained, or wet with fine dry soil or ash, or loose soil to increase soil evaporation. Anti-adult The leggy seedlings are caused by high seeding rate and high temperature and high humidity after emergence. Preventive measures include: (1) Strictly control the amount of seeding and time seedlings. When expanding the row spacing, prevent excessive shading. (2) Increase lighting as much as possible, even on cloudy days, make sure that the seedlings are exposed. (3) Control water and fertilizer. (4) Foliar application of 0.2% glutinous liquid fertilizer plus 0.2%-0.3% potassium dihydrogen phosphate, to promote the seedlings to grow strong, or use 5510-10010 chlorquat to inhibit seedling growth. Anti-aging Aging seedlings are caused by the age of the seedlings or the long time of the seedlings. Prevention measures include: (1) Strictly control the age of seedlings, and the length of seedlings should be appropriate. (2) The best method of controlling temperature is to use seedlings without water control. The time of low temperature during seedling growth should not be too long to prevent seedling ageing caused by prolonged drought. The 1010-3010 gibberellic acid was applied to the seedling bed of the aging seedlings with 500 times the euphobic liquid fertilizer or 300-500 times potassium dihydrogen phosphate to stimulate seedling growth. Sprout prevention Flash seedlings are mainly ventilated too quickly, causing seedlings to lose water quickly and cause the stems and leaves to dry and leaves wilting. Scientific ventilation is required during the nursery process, and ventilation is gradually performed from small to large. Open the South Gate before spring and open two in the spring. Anti-fouling There are two main reasons for the formation of stiff seedlings: First, the early spring is cold, the soil temperature at the seedbed is low, and the roots develop slowly to form rigid seedlings. Secondly, at the late stage of nursery, in order to prevent the seedlings from growing in length, they use less water or no watering. As a result, the roots of the apricot seedlings were severely affected by drought and formed rigid seedlings. In the early stage of nursery, try to raise the seedbed temperature and promote the development of roots. In the late stage of nursery, if the seedlings are long, the seedbed temperature should be reduced, the light intensity and illumination time should be increased, and avoid watering or watering. Gas poisoning In winter and spring greenhouses, unfermented organic fertilizer and ammonium bicarbonate are applied during seedling raising. The use of coal and plasticizers in the shed is prone to produce ammonia, carbon dioxide, chlorine, and other gases. The most effective prevention method is to enhance ventilation and scientific fertilization. . Prevention of injury Excessive application, excessive concentration, or drought on seedbeds can easily lead to phytotoxicity in vegetable seedlings. Preventive measures: (1) scientific and rational use of drugs. (2) Keep the seedbed moist before use. If phytotoxicity has occurred, spray water or relieve the drug promptly. Such as Fumei arsenic harm spray 0.2% zinc sulfate solution; dimethoate spray 0.2% borax or boric acid solution; paclobutrazol harm spray 0.05% gibberellin. Anti-miao hat “Dai Miao Miao†is when the cotyledon is unearthed, the belt is taken out of the soil, like a hat worn on the top of the cotyledon, which affects the normal development and photosynthesis of the cotyledon, which is mainly caused by the bed soil being too dry and the soil covering too thin. Preventive measures: (1) The bottom water of the seedbed should be poured, and the thickness of the cover soil should be uniform. Generally, small seed seeds cover 1-1.5 centimeters, medium seed 1.5-2 centimeters, and large seeds 3-4 centimeters. (2) Covering the bed with a plastic film to keep the soil moist. If a cap is to be worn, it can be sprayed with water. After the moisture is absorbed, brush the shell with a brush. Fiber Reinforced Plastics,Glass Reinforced Plastic,Reinforced Plastic,Frp Fiber Hebei Chunfeng International Trade Co., Ltd , https://www.cfcastiron.com