**Table 5.**

*Regressions between olive yield and soil nitrate, available phosphorus, and exchangeable potassium content, according to the three water regimes of olive groves studied.*



**Table 6.**

### **2.5 Correlation between parameters studied**

We looked for correlations between the olive yield and the soil contents of nitrates, available P, and exchangeable K (**Table 5**) on the one hand, and between the olive yield and the leaf contents of N, P, and K (**Table 6**) on the other hand. But none of these correlations have been confirmed for the three existing water regimes (rainy conditions, gravity, and drip irrigation system).

A study carried out in Syria revealed that the olive yield variability was explained at 68% by the amount of potassium available in the root zone, followed by total N with 58% and mineral N with 44% [5]. The same study showed the absence of correlation between yield and leaf N and P contents and a significant correlation (26%) between yield and leaf K content.

We also studied the relation between olive leaf nitrogen, phosphorus, and potassium contents and soil nitrates, available phosphorus, and exchangeable potassium contents at the 0–30 cm layer, always for each water regime adopted by farmers (rainy conditions, gravity, and drip irrigation system). The results obtained showed that olive nutrition parameters are not linked to soil fertility parameters in these orchards. The same result was reported by a study carried out in Tunisia for P and K [6].
