How to choose and buy high quality compound fertilizer?

How to choose and buy high quality compound fertilizer? Please introduce the methods for the selection and purchase of high-quality compound fertilizer can refer to the following methods: first, scientific selection of compound fertilizer according to the nature of fertilizer. At present, a considerable number of compound fertilizers sold in the market do not meet the national DB15063-94 standards. According to the national standard, the effective nutrient content of compound fertilizer (compound fertilizer) is 40% of the total amount of nitrogen, phosphorus and potassium of high concentration (≥), and 25% of nitrogen, phosphorus and potassium of low concentration, excluding trace elements and medium elements; the content of water-soluble phosphorus is 40%, the content of water molecules is less than 5%, and the particle size is 1mm to 4.75mm. Therefore, when choosing and purchasing compound fertilizer, we should not only look at the trademark and nutrient content, but also pay attention to the manufacturer and the place of origin. In addition, there are two kinds of potassium in compound fertilizer, one is potassium chloride, the other is potassium sulfate. Potassium chloride contains chlorine, which is not suitable for crops that avoid chlorine. Where there is no "S" symbol on the compound fertilizer bag, the potassium is potassium chloride. Avoid chlorine crops such as grapes, potatoes, tobacco, sugar beets, etc., must not be used, must choose the compound fertilizer marked with "S" symbol on the fertilizer bag, that is, the compound fertilizer composed of potassium sulfate. 2. Scientific selection of compound fertilizer according to crop varieties nitrogen, phosphorus and potassium compound fertilizer should be selected for field crops, nitrogen, phosphorus and potassium ternary compound fertilizer should be selected for high-yield wheat fields; powdered compound fertilizer should be used for closely planted crops such as wheat, rice and millet; granular compound fertilizer should be used for sparse planting crops such as corn. Vegetables, especially fruits and vegetables, root vegetables and fruit trees and other cash crops need more, so we should choose nitrogen, phosphorus and potassium compound fertilizer with high potassium content and low nitrogen content. 3. Scientific selection of compound fertilizer according to soil characteristics for soils with slightly alkaline, low organic matter content (soil ph is generally about 8.0) and lack of available nitrogen and phosphorus, acid compound fertilizer should be selected, such as monoammonium phosphate or humic acid nitrogen, phosphorus and potassium compound fertilizer, nitrogen and phosphorus compound fertilizer is suitable. However, alkaline compound fertilizer, such as diammonium phosphate, should be selected for a few red clay or acid brown soil. Fourth, according to the fertilization method, the scientific selection of compound fertilizer is to improve the fertilizer efficiency of compound fertilizer, and different dosage forms of compound fertilizer should be selected in different application methods. Granular compound fertilizer must be selected when it is used as base fertilizer, and the higher the hardness of the particles, the better, and the fertilizer effect is the longest. The selection of compound fertilizer composed of ammonium nitrogen in compound fertilizer is beneficial to improve the utilization rate of nitrogen. If used as topdressing, powdered compound fertilizer should be selected, and it should be noted that the content of water-soluble phosphorus in compound fertilizer phosphorus should be more than 40%, and nitrogen should be composed of ammonium nitrogen and nitrate nitrogen. In general, the effect of basic application of humic acid compound fertilizer is better than that of topdressing. Click to get more compound fertilizer application techniques