**2.3 Assessment of soil fertility**

Analyses of soil samples taken from the orchards have shown that the majority of these soils are basic, limestone, and largely poor to moderately provided with organic matter (**Table 3**).


#### **Table 3.**

*Soil sites characterization.*

Previous studies have shown that the olive tree tolerates a wide pH margin, but values between 7 and 8.5 allow its best development [1]. Other studies have also shown that excellent yield and vegetative growth can exist on olive grove soils with low limestone content and 50% limestone [2]. Therefore, the pH and % limestone of the studied soils are favorable for good growth and good development of the olive tree. We found that the average soil organic matter content was higher in olive orchards associated with intercropping compared to those conducted in monoculture (**Table 4**).

These results could be explained by the residues of these crops associated with the olive tree that certainly contributed to a greater accumulation of organic matter in the soil.

Soil analysis results showed that soil nitrate contents varied between 1.8 and 71.4 mg.Kg−1 and between 1.5 and 40 mg.Kg−1, respectively, for the 0–30 cm and 30–60 cm layers. For available phosphorus, the soils presented contents ranging from 1.3 to 59.3 mg.Kg−1 for the 0–30 cm layer and from 1.4 to 41.7 mg.Kg−1 for the 30–60 cm layer. Exchangeable soil potassium fluctuated between 43.8 and 1456.5 mg. kg−1 for the 0–30 cm layer and between 34.4 and 997.7 mg.kg−1 for the 30–60 cm layer. According to the interpretation standards for soil analyses defined by the California Fertilizer Association [3], 50% and 84.5% of the studied soils are poor in phosphorus, respectively, for the 0–30 cm and 30–60 cm layers. In contrast, soil potassium levels were low to medium in 15.5% and 55% of olive orchards, respectively, for soil layers 0–30 cm and 30–60 cm.

These results confirmed the existence of a deficiency in the fertilization practices adopted by the farmers.

#### **2.4 Evaluation of the nutrient state of olive orchards**

Olive leaf analysis revealed low levels of N, P, and K that varied, respectively, from 0.22 to 0.60%, from 0.04 to 0.26%, and from 0.34 to 1.08%. The results showed that leaf macro elements levels were, in the majority of cases, below the deficiency thresholds cited in the literature [4]. In fact, all of the orchards studied require nitrogen inputs and almost 91% of the orchards need potassium fertilization. As for phosphorus, it caused less problems compared to nitrogen and potassium since only a third of the orchards sampled required phosphorus input.


**Table 4.**

*Soil organic matter in intercropping system.*

*Management of Olive Tree Fertilization in Morocco DOI: http://dx.doi.org/10.5772/intechopen.104644*

