Fertigation is defined as the process of injecting fertilization, dissolved in irrigation water, permanently during the whole season according to the needs of each crop. Irrigation and fertilization are two relevant factors (in that order) and fundamental pillars associated to the delivery of essential chemical elements and the contribution of water demand. Therefore, our technical irrigation system can directly determine our project’s success, since it will help us reach the proposed objectives that determine the productive potential of the orchard, from the formation stages up to the productive ones; without leaving aside the weather, health, productive management and the combination variety/rootstock.

The effective and rational nutritional program is one of the keys to achieving our goals, but we must begin by understanding that each chemical element contributed as a fertilizer is essential to the lifecycle of cherry trees, since each one has a specific purpose, the way they move (or not) in soil and inside the plant, and the ability to express its deficiencies and excesses. From the above, it is important to understand and know that adult leaves are the indicator for the nutritional state of mobile elements, while new leaves are for the immobile elements that appear in the adapted table (Table 1).

The question that arises ahead is: how to achieve plants acquiring access to said chemical elements? To obtain the answer for plant nutrition, we must look at the subsoil, where the roots live, which carry out the absorption of nutrients from the soil solution to the plant, through an active transportation of ions; this requires energy and its accumulation is carried out against a concentration gradient, following synergisms and antagonisms according to their charges, in general terms, nutrients of equal ionic charges tend to compete, while those with different charges tend to favor their entry into the roots. These nutrients are available thanks to the transportation through water and irrigation and are transferred to the different organs of the plant by transpiration and by conduction through vascular bundles.

Now that we know that cherry trees need different essential chemical elements, how do we fertilize? The answer comes through an irrigation system, which is useful for delivering the nutritional contributions through each irrigation done according to the seasonal water demand and phenologic stage that we commonly call fertigation, which has some benefits:

• Application of water and nutrients directly to the volume of the active root zone, increasing the efficiency of fertilizer use, reducing loss and environmental impact. 
• Precise application of nutrients according to the specific demand for each phenologic stage of the cherry tree.
• Easy automation of fertilization work.
• Greater application uniformity in every irrigation, making a continuous application process without deficit periods.
• Possibility of utilization of low quality waters and soils. 
• Greater efficiency in machinery use, avoiding traffic with the fertilization work.
• Better productive performance.

Despite the benefits presented by the use of the fertigation method, we must consider that not all fertilizers are suitable for this, since this kind of method requires fertilizers to have a minimum solubility and to have compatibility between them.

In order to avoid incompatibility between fertilizers, as a prevention measure, we suggest being able to count on at least two preparation tanks.

Constructing a fertigation program:

For the construction of an adequate program for each case, it is necessary to take into consideration the following aspects:

1. Knowing the productive system (soil, health, climate/weather, nutrition, irrigation, phenology) in depth.
2. Knowing the adequate diagnostic techniques.
3. Determining needs and objectives to reach in the season.
4. Defining economical aspects.

Currently for the cultivation of cherry trees, the balance method is the most used by consultants and agronomists, and it is expressed in the following formula:

Where:

• Dose of the fertilizer is the quantity of nutrient, which must be transformed to the commercial product to be used, expressed in kg/ha.
• Demand is the need for fertilizer to be used during the phenologic stage, whether it is formation or production, considering in the latter the demand of nutrients per ton of fruit per hectare.
• Supply is the contribution of the soil for each nutrient, considering keeping a standard reserve in the soil.
• Efficiency of the fertilizer for each nutrient and according to the fertigation, being able to fluctuate between 30% and 85%.

Without a doubt a nutritional program assembled considering these aspects will have success in the objective sought, always taking into account the productive potential of the orchard.

The fertigation format should be the nutrition base of the soil from the operational and technical point of view, considering the efficiency of the use of fertilizers and the capacity that we have as an industry to manage this work.

We must not forget that the important basis of this nutrition method is governed by quality, implementation and management of the irrigation program; therefore having a system in place is the first step to achieving nutritional and productive objectives.