**1. Introduction**

With an area of around 1.17 million hectares, 60% of which is cultivated in rainfed conditions, the olive tree occupies a preponderant place in the national arboreal sector. It plays an important role in promoting the economy and employment as it contributes 5% to the agricultural gross domestic product (GDPA) and generates around 100,000 permanent jobs. Despite the continuous increase in its area, in response to the State's strategy (Green Morocco Plan) to reach 1.22 M ha by 2020, its production remains low and below the potential of the sector, especially in the rainfed system where yields in olives rarely exceed 3 T.ha−1. This low yield is the result of two main factors, which are as follows:


Fertilization, the subject of our chapter, is a very important cultivation technique for all agricultural production; it provides the crop with the nutrient requirements necessary for its growth and development. However, the majority of Moroccan olive growers, especially small farmers, consider the olive tree to be a hardy species that does not require maintenance. Also, the absence of fertilization standards for the olive tree, adapted to each agro-climatic region, leaves Moroccan olive growers with the obligation to follow traditional fertilization practices or in the best cases to fall back on recommendations obtained in other countries. Hence, the fertilizers brought by the Moroccan olive growers are, in the majority of cases, random both for quantity and quality, because it is not based on soil or vegetal analyzes.

All this prompted us to ask the following questions:

