Basically, fertilization is used to enrich the soil and treat deficiency or prevent deficiency in plants, for this reason, knowing the soil and plant conditions is the first principle for recommending fertilizer.
Due to the different behavior of plants in different conditions, it is impossible to implement a single instruction in all recommendations and get the same result. Tracking the results of fertilizer recommendations during the growth stages (observing the state of plant growth, including changes in roots, leaves, and fruit) is mandatory, and in case of deficiency symptoms, the cause should be investigated and necessary changes should be made.
Examining soil conditions, including soil pH, the amount of soil organic matter and the soil conditions of each region (deficiencies or excesses of elements), water quality (acidity level and bicarbonate levels), the type of water system and nutrition carried out in the past, to determine the nutritional needs Current and recommended fertilizer is important.
Examining the results of soil testing is very useful, but it is not enough, because soil analysis generally does not determine the amount of elements accessible by the plant, and due to different reactions in soil conditions and sampling methods, it cannot be definitively relied upon.
Laboratory results and overall performance observations should be considered for fertilizer recommendations.