Application technology and matters needing attention of compound fertilizer

Compound fertilizer has the advantages of high nutrient content, few by-components and improving the physical and chemical properties of fertilizer. The following aspects should be considered in the scientific application of compound fertilizer. 1. Select suitable varieties according to crop fertilizer requirements and soil characteristics. China has a vast land and a wide variety of crops. Suitable varieties should be selected according to the characteristics of soil fertilizer supply and nutrient demand of various crops in different areas. The compound fertilizer with high content of nitrogen and phosphorus should be selected for general grain crops, the compound fertilizer with high content of phosphorus and potassium should be selected for legume crops, and the ternary compound fertilizer suitable for soil and crops should be selected for some cash crops. In addition, soil properties and climatic conditions are also very important reference factors. For example, the compound fertilizer of nitrophosphate series should not be selected in southern rice producing areas; the compound fertilizer containing wolfberry soluble phosphorus is more suitable for acid soil; for saline-alkali soil and chlorine-sensitive crops, chlorine-containing compound fertilizer can not be selected. 2. According to the rotation system, the suitable varieties are selected according to the rotation system, and the varieties of compound fertilizer suitable for the upper and lower crops in a rotation cycle are also different. For example, in the wheat-maize rotation system, the wheat seedling stage is in the stage of low temperature growth and is particularly sensitive to phosphorus deficiency, so the varieties of compound fertilizer with high phosphorus should be selected, while the summer corn production stage is in the stage of high temperature, the soil releases relatively more phosphorus, and can make use of the after-effect of applying phosphate fertilizer in wheat stubble, so the varieties of compound fertilizer with low phosphorus can be selected. 3. Application techniques of different forms of compound fertilizers ① nitrate compound fertilizers are easy to lose nitrogen in rice fields, and more annual rainfall can also lead to nitrate loss in hilly tea areas. For the seedlings and young trees of fruit trees, the effect of ammonium compound fertilizer is better, and after mature and fruiting stage, nitrate compound fertilizer is more beneficial to the absorption and transportation of fruit trees. ② in paddy field, the yield of compound fertilizer containing potassium chloride is higher than that of compound fertilizer containing potassium sulfate, so it is suitable to choose compound fertilizer containing potassium chloride in paddy field. However, some crops are sensitive to chlorine, such as tobacco, grapes, potatoes and other taboo crops, potassium sulfate compound fertilizer should be used. According to the previous concept, the application of chlorine-containing fertilizer in the tea garden is easy to produce "chlorine damage", and the tea plant is also included in the taboo chlorine crop. 4. Although the formula of applying compound fertilizer in combination with elemental fertilizer is determined according to the nutrient demand of crops and the characteristics of soil fertilizer supply, it is difficult to fully meet the actual demand, so when applying compound fertilizer, it is very necessary to adjust the proportion of nutrient elements with elemental fertilizer according to the growth of crops in the field, so that it can finally meet the requirements of crop nutrition. 5. The application mode of compound fertilizer is composed of phosphorus or phosphorus and potassium, and most of them are granular, which dissolves more slowly than powdered unit fertilizer, so it is generally used as base fertilizer, seed fertilizer and topdressing fertilizer. ① base fertilizer, also known as base fertilizer, is the fertilizer used in soil preparation and ploughing. The application of compound fertilizer can meet the needs of crops for a variety of nutrients at seedling stage, which is conducive to strong seedlings, so adequate base fertilizer is the basis for high crop yield. The amount of base fertilizer is closely related to crop types and soil properties. ② seed fertilizer refers to the fertilizer used when sowing or transplanting. When using compound fertilizer as seed fertilizer, it is generally not suitable to plant fertilizer, and the direct contact between fertilizer and seedlings should be avoided, and fertilizer particles should be kept at a certain distance from seeds or seedlings in the soil. ③ topdressing refers to the fertilizer applied in the process of crop growth. The characteristics of topdressing application are relatively flexible, and suitable fertilizer application should be selected according to the symptoms of different periods of crop growth.