Mineral fertilization can maximize the yield of crops, thus preserving soil fertility and improving the profitability of agricultural activity. The goal pursued is the maintenance of a good level of minerals in the soil, in conditions of assimilability, so that the plant absorbs them in the quantity they need and at the most precise moment.
Once the crop cycle ends, the soil must retain the same conditions in which it was at the beginning. The ultimate goal of fertilization will be to conserve and improve the fertility of the soil, that is, it is not enough with the restitution of the elements that the harvest has extracted.
With mineral fertilization crops are developed, but always maintaining soil fertility for the benefit of future harvests.
The yield of the crop is limited by the nutritional element that is in a smaller amount. An excess in any other nutrient will not compensate for the deficiency of the limiting nutritive element. Only the highest yields and the best quality harvests can be obtained, if there is a balanced balance of nutrients. As the doses of a fertilizer are increased, the increments of harvest that are achieved by each new unit of fertilizer diminish. The optimum economic yield will be reached at the point where the yield obtained by the harvests compensates the costs of the fertilizers. 
Most important needs of the crops: N - P - K
Nitrogen (N): It is determinant in the growth and development of the plant as it helps in cell multiplication. In addition to leadiing to protein production, it has been found that there is a direct relationship between nitrogen and vitamins contents. 
Phosphorus (P): During the germination and nascence, the phosphorus favors the development of the roots, providing vigor to the crop. It also helps flowering and fruit setting, as well as being part of phospholipids, enzymes.
Potassium (K): It improves the resistance of the crops since it is an activator of photosynthesis and regulates the reserve substances. It intervenes in the different enzymatic reactions and decreases perspiration.
A positive interaction between nitrogen and phosphorus is decisive in the initial moments of cultivation. In the same way that the availability of phosphorus and potassium is fundamental to facilitate the retention of water and the creation of proteins and sugars.