It is not appropriate to over-apply untreated manure. The use of farmyard manure in greenhouses must be fully decomposed, because no farmhouse manure after decomposing has pathogens and eggs. After the vegetables are applied, it is easy to spread the disease. In addition, if the farmhouse fertilizer is put into a greenhouse and then cooked, the ammonia produced will burn the seedlings.
It is not appropriate to apply fertilizers that tend to increase the concentration of soil solution. After potassium chloride, potassium sulfate, ammonium sulfate and other fertilizers are applied to the soil, acid ions, chloride ions, etc. are not easily absorbed by the crop and remain in the soil, which will increase the concentration of the soil solution and damage the normal growth of the crop. Therefore, fertilization in greenhouses should use ammonium phosphate, diammonium phosphate, urea, calcium superphosphate, ammonium nitrate, and special BB fertilizer.
It is not appropriate to use fresh human excreta. After the fresh human waste is applied to the greenhouse soil, due to the high temperature inside the greenhouse, it will soon decompose and decompose, affecting the absorption of water and nutrients by the crops, generating large amounts of ammonia gas, poisoning the crops, and then burning seedlings, resulting in severe The plants became brown and dry.
Topsoil fertilizer is not suitable. There are many opportunities for nitrogen topsoil application and contact with air. The ammonia produced by nitrogenous fertilizers can easily poison plants and also reduce fertilizer efficiency. The deep application of chemical fertilizers can reduce the accumulation of nitrate in crops and increase the utilization rate. The topdressing is applied with deep ditching. After the application, the soil is tightly closed and the water is promptly applied to dilute the fertilizer.
Topdressing fertilizer should not be excessive. Greenhouse topdressing should strictly follow the principle of “a small number of times†to prevent excessive fertilization. The excessive use of chemical fertilizers at one time not only causes waste, but also increases the concentration of soil salt and endangers vegetables. The limits for applying fertilizer once per acre for different soils are: 15 kg of ammonium nitrate sandy loam, 18 kg of loam and clay, 10 kg of urea sandy loam, 12 kg of loam or clay, 40 kg of superphosphate sand loam, 50 kg of loam or clay Diammonium phosphate sand loam 25 kg, loam or clay 35 kg.
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