What is compound fertilizer? What are the advantages of mixed application? What are the points for attention?

What is compound fertilizer? What are the advantages of mixed application? What are the points for attention? Compound fertilizer refers to the chemical fertilizer which contains nitrogen, phosphorus and potassium at the same time or only any two of them. For example, the compound fertilizer containing any two of the three elements is called binary compound fertilizer, and the fertilizer containing nitrogen, phosphorus and potassium is called ternary compound fertilizer.

Fertilizer mixing refers to the mechanical mixing of two or more kinds of simple fertilizers or compound fertilizers. Its advantages include:

① can select suitable fertilizer varieties according to different soils and different crops, and prepare them according to the appropriate proportion.

② can not only exert the interaction between nutrients, but also save the labor of fertilization by applying multi-component fertilizer at one time.

③ can improve some bad physical and chemical properties of fertilizer, such as moisture absorption, caking and high content of free acid.

Note: points for attention in mixed use

① fresh compost and barnyard manure can be mixed with plant ash and lime because the former will produce organic acids in the decomposition process, affecting the activity of microorganisms. Adding 2%-3% lime or 5% plant ash can adjust acidity and promote fertilizer ripening.

② superphosphate can be mixed with an appropriate amount of plant ash, because calcium superphosphate usually contains 5% free acid. For example, mixing 5% of plant ash with phosphate fertilizer can eliminate the adverse effects of free acid in phosphate fertilizer, while the fertilizer efficiency of phosphate and potash will not be reduced.

③ plant ash can not be mixed with mature human feces and urine, because the main component of plant ash is potassium carbonate, and its aqueous solution is alkaline, while nitrogen in mature human feces and urine exists in the form of ammonium carbonate, which will volatilize ammonia when it encounters alkali, resulting in nitrogen loss and reducing fertilizer efficiency. According to the experiment, after mixing 1 part of plant ash and 1.5 parts of human feces and urine for 3 days, the loss of nitrogen cable can reach 27%.

However, not all fertilizers can be made into mixed fertilizers. When considering the mixing of several fertilizers, three principles should be followed:

① did not cause fertilizer nutrient loss or decrease in fertilizer availability. Ammonium nitrogen fertilizers such as ammonium sulfate or compound fertilizers containing ammonium nitrogen, and water-soluble phosphate fertilizers such as calcium superphosphate can not be mixed with alkaline fertilizers such as plant ash and lime nitrogen, so as to avoid nitrogen loss and reduce the effectiveness of phosphorus.

② will not produce bad physical properties.

③ is beneficial to improve fertilizer efficiency, work efficiency and reduce fertilizer cost.