1. Excess nitrogen fertilizer 1. Symptoms The leaves of fruits and vegetables are large and dark green, the petiole and internodes are long, the plants are prolonged, the yellowing is sometimes seen between the veins (the lower leaves of the tomato are easy to curl), the buds are slender (the ovary is smaller). The fruit grows slowly, and it is easy to fall and drop fruit. Tomatoes are prone to umbilical rot, and celery is prone to heart rot. 2. Causes of fruit and vegetables vegetables prematurely before the fruit set to promote water and water, plant reproductive growth is inhibited, nutrient growth is too strong, poor ventilation and light, resulting in falling flowers and fruit. Excessive nitrogen affects the absorption of calcium by plants, resulting in tomato umbilical rot and celery heart rot. 3. Control methods 1 Cultivate strong seedlings to regulate water and fertilizer in the shed, so that the vegetative growth of fruit and vegetable vegetables is coordinated with reproductive growth. Seedlings should be timely before fruit set to prevent plant growth. The temperature in the shed is appropriately lowered, and the night temperature is maintained at 12 ° C - 14 ° C. 2 Balanced fertilization According to the demand for nutrition in different periods of vegetable growth, balanced fertilization of nitrogen, phosphorus and potassium is required, and nitrogen fertilizer is applied. 3 Appropriate calcium supplementation For the soil with more nitrogen fertilizer or nitrogen fertilizer accumulation in the early stage, in order to prevent the disease caused by calcium deficiency, foliar top dressing can be carried out with 0.5%-1% calcium chloride or 0.5% calcium nitrate. Fruit and vegetable vegetables are sprayed once every 7 days from the initial flowering period and sprayed three times in a row.
Second, high concentration of salt hazards Symptoms The leaves are dark green and have a hardening sensation, the heart leaves are curled, the young leaves and the flower buds have dry tips, and the plants are dwarfed. The shoulders of the tomato fruit have dark green stripes, which are distinct from the color of other parts of the fruit, and the fruit grows slowly. Plants that are seriously endangered may even appear wilting and withering. 2. The cause of excessive use of livestock excrement or excessive application of ammonium chloride or potassium chloride causes the chloride ions to accumulate in the tillage layer, causing the soil salt concentration to be too high, the root growth of the plant is blocked, leading to rooting and seriously affecting the plant. Growing. 3. Control methods 1 Livestock manure should be fully decomposed, and should be thoroughly mixed with the soil during application to avoid the single use of chemical fertilizer. 2 When the soil salt concentration is too high, the amount of irrigation and the number of irrigation should be increased. Salt should be drained during land recreation.
Third, the ammonia hazard 1. Symptoms Watery immersion occurs between the leaf margins or veins at the onset of the disease, especially in the case of continuous cloudy days, the leaves may appear wilting. After 2 days - 3 days, the affected part turned white or brown dry. 2. Causes After the application of unfertilized chicken manure and cake fertilizer, under the action of high humidity and high temperature in the shed, the ammonia is quickly fermented to produce crops. In addition, the application of ammonium bicarbonate and urea directly on the soil surface will also produce ammonia gas, which will cause damage to the leaves of the plant. If you use the pH test paper to take the water drop test in the shed, the ammonia value is very likely to occur when the pH value is >8. 3. Control method 1 Chicken manure, cake fertilizer and other organic fertilizers must be fully decomposed before application. Urea\ammonium bicarbonate should be dissolved in water or used in buried soil. Avoid partial application of nitrogen fertilizer. 2 Before and after fertilization, the ventilation should be increased. Especially the sheds with ammonia hazard should be quickly ventilated. For the lightly affected vegetable crops, water and fertilizer management should be strengthened, and the curtains should be shaded at noon to promote their growth.
Fourth, the nitrite gas hazard 1. Symptoms Nitrous acid gas hazards are highly prone to occur on consecutive cloudy days. At the beginning of the disease, the leaf margin and the tip of the leaf were water-soaked. After 1 day to 2 days, the diseased part was white and dry. In the case of acute hazards, many irregular white lesions appear in the leaves, and even the entire leaf is dry. 2. Causes of the disease Excessive application of nitrogen fertilizer, poor soil permeability, low ground temperature, hindered the nitrification process of nitrogen fertilizer, and nitrite nitrogen accumulated in the soil. When the soil is acidic (pH < 6), nitrous acid gas overflows from the soil and is toxic to vegetables. 3. Control method 1 Immediately ventilate and reduce the concentration of nitrous acid gas. 2 Use lime to neutralize soil acidity, and combine cultivating loose soil to increase ground temperature.
Second, high concentration of salt hazards Symptoms The leaves are dark green and have a hardening sensation, the heart leaves are curled, the young leaves and the flower buds have dry tips, and the plants are dwarfed. The shoulders of the tomato fruit have dark green stripes, which are distinct from the color of other parts of the fruit, and the fruit grows slowly. Plants that are seriously endangered may even appear wilting and withering. 2. The cause of excessive use of livestock excrement or excessive application of ammonium chloride or potassium chloride causes the chloride ions to accumulate in the tillage layer, causing the soil salt concentration to be too high, the root growth of the plant is blocked, leading to rooting and seriously affecting the plant. Growing. 3. Control methods 1 Livestock manure should be fully decomposed, and should be thoroughly mixed with the soil during application to avoid the single use of chemical fertilizer. 2 When the soil salt concentration is too high, the amount of irrigation and the number of irrigation should be increased. Salt should be drained during land recreation.
Third, the ammonia hazard 1. Symptoms Watery immersion occurs between the leaf margins or veins at the onset of the disease, especially in the case of continuous cloudy days, the leaves may appear wilting. After 2 days - 3 days, the affected part turned white or brown dry. 2. Causes After the application of unfertilized chicken manure and cake fertilizer, under the action of high humidity and high temperature in the shed, the ammonia is quickly fermented to produce crops. In addition, the application of ammonium bicarbonate and urea directly on the soil surface will also produce ammonia gas, which will cause damage to the leaves of the plant. If you use the pH test paper to take the water drop test in the shed, the ammonia value is very likely to occur when the pH value is >8. 3. Control method 1 Chicken manure, cake fertilizer and other organic fertilizers must be fully decomposed before application. Urea\ammonium bicarbonate should be dissolved in water or used in buried soil. Avoid partial application of nitrogen fertilizer. 2 Before and after fertilization, the ventilation should be increased. Especially the sheds with ammonia hazard should be quickly ventilated. For the lightly affected vegetable crops, water and fertilizer management should be strengthened, and the curtains should be shaded at noon to promote their growth.
Fourth, the nitrite gas hazard 1. Symptoms Nitrous acid gas hazards are highly prone to occur on consecutive cloudy days. At the beginning of the disease, the leaf margin and the tip of the leaf were water-soaked. After 1 day to 2 days, the diseased part was white and dry. In the case of acute hazards, many irregular white lesions appear in the leaves, and even the entire leaf is dry. 2. Causes of the disease Excessive application of nitrogen fertilizer, poor soil permeability, low ground temperature, hindered the nitrification process of nitrogen fertilizer, and nitrite nitrogen accumulated in the soil. When the soil is acidic (pH < 6), nitrous acid gas overflows from the soil and is toxic to vegetables. 3. Control method 1 Immediately ventilate and reduce the concentration of nitrous acid gas. 2 Use lime to neutralize soil acidity, and combine cultivating loose soil to increase ground temperature.
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