How to choose a compound fertilizer? Remember these five reference criteria

Because compound (mixed) fertilizers contain a variety of nutrients needed by plants, they produce a significantly greater yield increase than single-element fertilizers, and this concept of fertilization has been recognized and accepted by the vast majority of farmers. However, due to various constraints, most farmers do not know that even if they buy qualified compound (mixed) fertilizers, improper selection or improper application can lead to reduced yields or even total crop failure. Therefore, I would like to offer a few superficial views on how to select a suitable compound fertilizer, for the reference of farmer friends only.

Local soil characteristics

For farmer friends in the alkaline soils of the north, an acidic compound fertilizer should generally be chosen; conversely, for farmer friends in the acidic soils of the south, an alkaline compound fertilizer should be chosen; for soils with low organic matter content, an organic compound fertilizer or an organic-inorganic compound fertilizer can generally be applied as a supplement.

In addition, for the alkaline soils of the northwest, it is generally not suitable to choose and apply compound fertilizers produced with citrate-soluble phosphorus, potassium chloride, or ammonium chloride as raw materials.

The crop variety being grown

For field crops, a nitrogen-phosphorus-potassium ternary compound fertilizer should generally be chosen; for economic crops such as vegetables and fruit trees, especially root crops, which need more potassium, a nitrogen-phosphorus-potassium ternary compound fertilizer with higher potassium content should be chosen; for chlorine-sensitive crops such as grapes, potatoes, tobacco, and sugar beets, it is not suitable to apply compound fertilizers with high chloride ion content produced with potassium chloride or ammonium chloride as raw materials.

Fertilizer properties

Farmer friends should ordinarily learn and grasp a little common knowledge about fertilizers, so that they have a clear idea when purchasing fertilizer. For example: the GB15063-2001 national standard stipulates that the effective nutrient content of compound (mixed) fertilizers is divided into three levels, high, medium, and low: high-concentration nitrogen-phosphorus-potassium content ≥40%, medium-concentration nitrogen-phosphorus-potassium content ≥30%, low-concentration nitrogen-phosphorus-potassium content ≥25%, not including trace elements and secondary elements; water-soluble phosphorus content ≥40%, etc. Different nutrient contents mean different application amounts and technical requirements, and of course different prices as well.

Fertilization method

To improve the fertilizer efficiency of compound fertilizers, different dosage forms of compound fertilizer should be chosen for different fertilization methods. For example, when used as a base fertilizer, granular compound fertilizer should be chosen, or a compound fertilizer containing slow- and controlled-release fertilizer should be chosen, as its fertilizer effect lasts longer and it helps improve the utilization rate of nitrogen. For humic acid compound fertilizers, the effect of base application is generally better than that of topdressing.

According to the principle of balanced fertilization

Farmer friends should ordinarily keep in contact with agricultural technicians more often, understand soil characteristics and the fertilizer requirements of crops, and it is best to combine this with soil testing and formulated fertilization, following the principle of balancing crop nutrition and making a reasonable formula according to the soil testing results, supplementing whatever is lacking, so as to achieve a balanced supply of crop nutrient elements. Finally, what needs attention is that the nutrients in compound fertilizers are relatively fixed, so they must not be chosen and applied blindly, nor applied as a single-element fertilizer, to avoid unnecessary losses and waste from doing so.