One, excess nitrogen fertilizer 1. Symptoms Vegetables Vegetables have large, dark green leaves, long petiole and internodes, long and easy plant growth, yellowing between leaves and veins (the lower leaves of the tomato tend to curl), and slender buds (small ovaries of the melons), Slow fruit growth, easy to drop, fruit drop. Tomato is easy to get rot of the umbilical rot, celery is easy to get heart rot. Second, the high concentration of salt hazards 1. Symptoms Symptoms of dark green leaves have sclerotic sensations, curly leaves, and dry tips at young leaves and scapes, and dwarfing. There are dark green stripes on the shoulders of tomato fruit, which are obviously different from the color of other parts of the fruit. The fruit grows slowly. Plants that are seriously endangered may even show wilting and withering. 1. Symptoms of symptoms appear at the beginning of the leaf margin or between the veins of the water, especially in sunny days, the leaves may appear wilting. After 2 days - 3 days, the affected area turned white or brown and dry. Tri Fold Wheelchair Ramps,Folding Suitcase Ramp,Suitcase Ramps For Scooters,Suitcase Ramps For Wheelchairs Active Life Healthcare Co.,Ltd , https://www.alh-med.com
2. Reasons for the occurrence of fruit and vegetables in the fruit before the premature application of fertilizer to promote waterlogging, plant growth inhibition is inhibited, vegetative growth is excessive, poor ventilation and light transmission, resulting in falling flowers and fruit. Too much nitrogen affects the plant's absorption of calcium, resulting in tomato umbilical rot and celery heart rot.
3. Prevention and control methods 1 Cultivate strong seedlings to regulate water and fertilizer in the shed, so that the vegetative growth and reproductive growth of fruit and vegetable vegetables are coordinated, and the seedlings should be timely planted before the fruit setting period to prevent plant growth. Properly reduce the temperature inside the shed. The night temperature is maintained at 12°C-14°C. 2 Balanced fertilization According to the demand for nutrients at different stages of vegetable growth, balance fertilization with nitrogen, phosphorus and potassium can be achieved, and nitrogen fertilizer should be avoided. 3 Proper calcium supplementation For soil with more nitrogen fertilizer or more nitrogen fertilizer accumulated in the early stage, in order to prevent the diseases caused by calcium deficiency, 0.5%-1% calcium chloride or 0.5% calcium nitrate may be used for foliar dressing. Fruit vegetables were sprayed once every 7 days from the beginning of the flowering period and sprayed three times in succession.
2. Causes Excessive use of livestock urine or excessive application of ammonium chloride, potassium chloride, chloride ions accumulated in the cultivation layer, causing excessive salt concentration in the soil, plant root growth is blocked, resulting in burning roots, seriously affecting the plant Grow.
3. Control methods 1 Livestock manure should be fully decomposed, and the application should be fully mixed with the soil to avoid single use of chemical fertilizers. 2 When the soil salt concentration is too high, increase the amount of irrigation and the number of irrigations. During the land reclamation, the salt should be drained.
Third, ammonia hazard
2. After the application of unfamed chicken manure and cake fertilizer, under the effect of high humidity and high temperature in the shed, rapid fermentation produces ammonia hazard crops. In addition, the direct application of ammonium bicarbonate and urea to the soil surface will also produce ammonia gas, which will cause plant leaf damage. If pH test paper is used to draw the water drop test in the shed, pH value >8 can easily cause ammonia hazard.
3. Control methods 1 Chicken manure, cake fertilizer and other organic fertilizers must be fully cooked before application, urea \ ammonium bicarbonate should be dissolved in water after use or buried soil application. Avoid partial nitrogen fertilizers. 2 Ventilation should be increased before and after fertilization, especially for sheds with existing ammonia hazards. The management of water and fertilizer should be strengthened for the light-vegetable crops that were damaged, and the curtains should be shaded at noon to promote their growth.
Fourth, nitrite gas hazard
1. Symptoms of nitrite gas are prone to occur when the symptoms are continuously cloudy. At the beginning of the disease, the leaf margins and tip were immersed in water, and the diseased part was white and dry after 1 to 2 days. In the event of acute damage, many irregular white lesions appear in the leaves, and even the entire leaf is dry.
2. The reasons for the occurrence of excessive nitrogen fertilizer, poor soil permeability, low ground temperature, so that the nitrification process of nitrogen fertilizers blocked, nitrite nitrogen accumulation in the soil. When the soil is acidic (pH 3. Control method 1 immediately ventilated to reduce the concentration of nitrous acid gas. 2 Use lime to neutralize soil acidity, combined with cultivator loose soil, increase the temperature.