The compost or NPK fertilizer as its name suggests is a compost or fertilizer that is made up of the three elements or, better said, primary macroelements. These macroelements are nitrogen (N), phosphorus (P) and potassium (K).

Within the entire range of available fertilizers, we can say that NPK fertilizers are the most complete nutritionally speaking, since the three main essential macronutrients are provided to the crop or plant at the same time of application.

NPK subscription: How are the declared contents expressed?

It is important that we know when buying an NPK fertilizer what is its actual content and availability for the target crop or plant. We can always know this through the technical sheet of the product that the manufacturer must provide us by law.

In the technical sheet you must indicate the minimum declared content. In this case we must know the following:

In the first place, nitrogen has to be expressed in the form of Total N to later express what% is nitric N, ammoniacal N or ureic N.

Second, P must be expressed in the form of phosphorous pentoxide (P 2 O 5 ) and they must also indicate the amount in% of P that is soluble in water.

Finally, K must be expressed in the form of potassium oxide (K 2 O) and will indicate the% provided by said fertilizer.

The NPK fertilizer  can be complex or mixture. The difference between the complexes and the mixed ones is only that in the complexes each granule is made up of the same richness and in the mixed ones, each granule provides one or two macronutrients and their mixture adds the total richness.

On the other hand, an NPK fertilizer can also be solid or liquid. Depending on the method used to contribute it to the soil or to the plant, thanks to new technologies, it is possible to manufacture it solid, generally for extensive cultivation; soluble solids to apply them via fertigation to woody and horticultural crops, or to make them liquid which can be used in extensive crops and via fertigation. The NPK fertilizer solids or soluble solids are richer in NPK than liquids.

Soluble solid fertilizers can be used foliar route in certain crops. If we talk about the formulas or richness of NPK fertilizers we can say that there is a great variety of compositions. The best known formula of all and the most balanced is 15-15-15.

When to apply macroelements and what do they contribute to the crop?

The NPK high in N apply to the beginning of the cycle of the crop or in the growth phase. High in P are used in the implantation of crops or for their use in the moments before flowering and flower setting in the case of woody and horticultural crops. Finally, NPK fertilizers high in K are used in the final stages of the crop, coinciding with maturation and fruiting.

Thanks to NPK fertilizers and their wide variety of formulas, forms of presentation and richness, we can design a fertilization plan according to any crop to be successful.