Common Shed Lack Factor and Its Remedial Measures
In the greenhouse, due to the continuous cultivation of vegetables, the soil nutrients in the shed can not meet the needs of the growth and development of vegetables, affecting the yield and quality of vegetables. The deficiency symptoms of common vegetables and their remedial measures are described as follows: 1. The symptoms of nitrogen deficiency are plant dwarf, lighter or reddish leaf color, and some of its leaves turn yellow; stem color is also often changed, and development is rapid and dry. After the brown, stem short and thin. Remedial measures: When nitrogen deficiency is found, timely nitrogen fertilizers such as ammonium sulfate and urea should be traced, but ammonium bicarbonate is generally not used in sheds. 2. Phosphorus-deficient plants grow slowly, but the leaves become smaller but do not lose the green, and even the darker leaves become darker and the stalks become thinner. Remedy: Apply calcium phosphate 50-100 kg/mu as base fertilizer; or apply 0.3%-0.5% potassium dihydrogen phosphate solution in the growth process. 3, The potassium-deficient leaves are light grayish green, and the leaf margins turn yellow and dry, and the stems are thin and hard. Remedy: Immediately chase fast-acting fertilizers, such as potassium sulfate, etc., and spray 0.3%-0.5% potassium dihydrogen phosphate solution. 4, magnesium deficiency old leaves lose green yellow and veins are still green, leaves become brittle, leaf margin roll, sometimes leaves appear purple. Remedial measures: Immediately after the discovery, the leaves were sprayed with 0.5% magnesium sulfate solution. 5, boron-deficient growth point atrophy, brown and dry, plant type plexiform, curved leaves, resulting in leaf burning symptoms. Control methods: Mushi 0.5 kg borax as a base fertilizer, but also foliar spray 0.1% -0.2% boric acid. 6, young copper leaves showed atrophy, weak plant growth, leaf color changes, white tips. Remedy: Foliar application of 0.05% copper sulfate solution, in addition, more application of organic fertilizer can also prevent the occurrence of copper deficiency syndrome. 7, lack of manganese leaf necrosis of young leaves, veins remain green, late leaves. Control measures: Try to keep the soil as neutral as possible. Apply 1-4 kg of manganese sulphate as base fertilizer, and also apply topdressing 0.2% manganese sulfate. 8, iron deficiency young leaves showed a retreat between the veins, yellow-white, when the whole leaf becomes yellow and white, dry. Remedy: Foliar application of 0.1% -0.2% ferrous sulfate solution.