There is no rainwater leaching in protected areas such as greenhouses and greenhouses. With more fertilization, the salts in the soil will gradually move upward due to irrigation and accumulate in the soil surface. When the amount of fertilizer applied exceeds the absorption of vegetables and other crops, the salts in the soil will increase and the concentration of soil solution will increase. The concentration of soil salt in protected areas increases with the extension of the service life. The long-term use of chemical fertilizers has aggravated the accumulation of salts. Due to the problems of high salt content, acid hazards, and continuous cropping obstacles in the protected soils, it is necessary to gain advantages and avoid disadvantages in fertilization techniques in order to obtain continuous yield increase of crops. It is advisable to use organic fertilizers with more cellulose (higher ratio of carbon to nitrogen) to increase organic fertilizers. Organic matter will form organic colloids such as humic acid during the decomposing process. The colloids are strongly adsorbed and can adsorb semi-soluble mineral nutrients such as ammonium ions, potassium ions, and calcium ions and other cations around themselves. This adsorption is dynamic and releases into the solution when the concentration of the soil solution decreases. The application of organic fertilizers can increase the buffer capacity (regulatory capacity) of soil nutrients, prevent the accumulation of salts, and delay the process of secondary salinization of soil. The scientific monitoring of the spread of fertilization uses a conductivity meter to monitor the soil solution concentration. Fertility disorders occur in vegetables that exceed a certain EC value (soluble salt content in the substrate) and fertilization is stopped when appropriate threshold values ​​are found. Salts deep in the soil of soil protection areas are concentrated in the top soil layer. Generally, the salt index is 0 to 5 centimeters in soil, 100 to 5 to 25 centimeters in soil and 60 to 25 to 50 centimeters in soil. After the crops have been harvested, the land is turned deep and the topsoil rich in salt is turned to the lower layer. The lower soil containing less salt is turned to the upper layer to reduce the salt damage in the soil. Change the gaps, remove the film, rain, dissolve the salt, or wash and wash the salt. After the summer crops are harvested, remove the film and soak the salt. About 10 days in the rainy season, no film is applied, and it is a simple and feasible measure to eliminate the secondary salinization of soil. This will not only wash the salt, but also kill the germs, which will benefit the high yield and stable production of the crop. Deep basal fertilizer, limited application of top dressing chemical fertilizer as a base fertilizer deep application, when applied as a small amount of top dressing. Fertilizers and organic fertilizers are mixed and spread after being spread. Fertilizers are ploughed into the soil to prevent excessive fertilization on the soil surface to increase the salt content of the topsoil. When applying topdressing, strict control of the amount of fertilizer applied each time can increase the frequency of fertilization and avoid increase of soil solution concentration. Advocating top-dressing root dressings does not increase salt content in the soil. Urea, superphosphate, potassium dihydrogen phosphate, and some trace elements can be used as top-dressing varieties. Covering the ground with a plastic film or straw to cover the ground can reduce surface water evaporation, block soil salt from moving upwards, and suppress surface accumulation of salt. Surgical Drapes,New Nonwoven Drapes,Pediatric Universal Drapes,Banded Bag Surgical Drape Zhende Medical Co.,Ltd , https://www.zdmedicalproduct.com