The composition of compound (compound) fertilizer is complicated. Fertilizer users should apply compound fertilizer correctly according to the relevant instructions on the product package to avoid crop damage or production failure:

(1) Compound (combined) fertilizer is generally used as base fertilizer and top dressing, and cannot be used as seed fertilizer and foliar top dressing to prevent seedling burning.

(2) Compound fertilizers with the word "chlorine" marked on the product packaging bag. "Chlorine-avoiding" crops and saline-alkali land should be used as little as possible, preferably not. It is most suitable for the cultivation of paddy crops such as rice, because chloride ions can be leached to the lower layer with water and will not accumulate in the soil.

(3) Compound fertilizers without the word "chlorine" on the product packaging bag. Compound fertilizers that do not specify "chlorine" contain no ammonium chloride and potassium chloride, and the price of the product is higher. It is suitable for crops with higher economic efficiency or chlorine avoidance, including fruit trees. Tobacco and root crops, etc. The application of this series of compound fertilizers is better in saline-alkali soil.

(4) "Citrate-soluble phosphorus" is marked on the product packaging bag, indicating that the content of water-soluble phosphorus in the product is very low, and the product is suitable for application on the acidic soil south of the Yangtze River.

(5) The fact that "citrate-soluble phosphorus" is not marked on the product packaging bag indicates that the content of water-soluble phosphorus in the product is relatively high. The compound fertilizer is suitable for most soils and crops in my country.

(6) "Containing nitrate nitrogen" is marked on the product packaging bag. This compound fertilizer is not suitable for application on paddy field soil, so try not to use compound fertilizers marked with "nitrate nitrogen" when planting aquatic organisms. Generally speaking, the price of compound fertilizers containing "nitrate nitrogen" is generally higher than that of other compound fertilizers with the same nitrogen content. Therefore, compound fertilizers containing "nitrate nitrogen" are suitable for application on economic crops with higher economic benefits. Such as tobacco, vegetables, etc.

(7) "Containing nitrate nitrogen" is not marked on the product packaging bag. The compound fertilizer is suitable for paddy field and dryland crops.