Scientific application technology of chemical fertilizer

After urea is applied unfavorable immediately watering: urea is applied after the soil, can become acyl ammonium very quickly, very easy with water loss, after applying accordingly unfavorable immediately watering, also do not apply before heavy rain.Urea can be applied as topdressing fertilizer outside the root, which can effectively prevent early aging of plants due to nitrogen deficiency in the middle and later stages of crops, but it should be noted to avoid burning seedlings due to fertilizer damage.Urea should not be used as seed fertilizer.
Phosphate fertilizer should not be distributed: it is difficult to be absorbed by crops due to its small activity.Therefore, in the application of phosphate fertilizer, should be used as the base fertilizer, and more concentrated application in the seeding ditch or nest, it is best to mix with organic slag fertilizer compost reapplication for a period of time.
Potassium fertilizer should not be applied in the later stage of crop growth: potassium in the lower stem and leaves of the crop can be transferred to the tender part at the top for reuse.Therefore, potash fertilizer should be applied in advance in the seedling stage of crops or in the early stage of reproductive growth, or as a one-time base fertilizer application.
Ammonium bicarbonate is suitable for deep application: because ammonium bicarbonate is very unstable, the most easy to decompose into ammonia gas and volatilization, and the higher the temperature, the greater the volatilization loss, so should not be used in the greenhouse greenhouse greenhouse, also can not be spread on topsoil, should be ditch application or hole application.
Avoid long-term use of ammonium sulfate: ammonium sulfate belongs to physiological acid fertilizer, if applied in the field for a long time, it will increase the acidity of the soil, damage the soil aggregate structure, make the soil harden and reduce the physical and chemical properties, which is not conducive to fertilizing the soil.
Chlorinated fertilizer should not be applied to saline-alkali land and chlorinated crops: ammonium chloride, potassium chloride and other chlorinated fertilizer applied into the soil after decomposition will lead to soil acidification over time, in the use of saline-alkali land, will aggravate salt damage.Chlorinated fertilizers applied to chlorine-resistant crops such as potato, watermelon and grape can reduce the starch and sugar content of the products and affect the yield and quality of the products.
Nitrate fertilizer should not be applied in paddy fields and vegetable fields: ammonium nitrate, sodium nitrate and other nitrate fertilizers are easy to produce denitrification and loss of nitrogen after being applied into paddy fields.Nitrogenous nitrogen fertilizer applied to vegetable fields will increase the nitrate content of vegetables exponentially, and can be reduced to nitrite in the human body, great harm to the human body.