There are certain nutritional deficiencies that are very difficult to counteract through traditional fertilization, due to soil conditions, weather, etc... Adequate fertilization can be used to accelerate growth, when it does not grow at the desired rate, or to counteract a lack of microelements (Fe, Mn, Zn, Cu, Mo, B), trace elements (Ca, Mg, S) and also macroelements (N, P, K). Many of these nutrients move to deep layers of the soil with the rains, or are degraded by oxidation, which means that, while they are not available to the plant, they can contaminate aquifers or groundwater. The high precision that endotherapy allows when supplying nutrients means that this technique has been the subject of numerous studies by renowned researchers around the world, demonstrating that, by injection into the trunk, the amount can be reduced by up to 90%. fertilizer products, water and energy, compared to traditional fertilization (fertigation, spraying, or soil amendments), with the consequent environmental benefit, and especially the benefits for crops, which increase in quantity and quality. It is the lack of iron (iron chlorosis), by far, the most difficult to counteract and, therefore, the one that has led to the most research. But not only this deficiency, but also that of other microelements and trace elements is counteracted in a highly effective, evident and long-term manner, by means of endotherapy, which may even have to be applied once every 2-3 years.