Best Management Practice of Nutrient of Olive Orchards in Rainfed and Irrigated Areas of Morocco

This experiment began in 2014 with the objective to assess the effect of improved methods for nutrient recommendations in olive orchards in Morocco. Two on-farm experimental sites were selected in the irrigated and rain-fed areas of Marrakech and Essaouira provinces. The planting density were 204 trees/ha under irrigated and 25 trees/ha under rain-fed conditions. At each site, four treatments were used: 1) no additional fertilization (control); 2) farmer fertilizer practice (FFP); 3) fertilization based on nutrient removal (NR); and 4) fertilization based on foliar analysis (FA). Two olive varieties, Haouzia and Menara, were studied in both sites. The applied nutrients in the different treatments at the irrigated site in 2017 were 0.50 kg nitrogen (N)/tree for FFP, 0.50 kg N + 0.18 kg P₂O₅ + 0.41 kg K₂O/tree for FA and 0.52 kg N + 0.25 kg P₂O₅ + 0.88 kg K₂O/tree for NR. In the rain-fed site, nutrients applied in different treatments were: FFP (no additional fertilizers were applied by farmer), 0.27 kg N + 0.25 kg P₂O₅ + 0.60 K₂O kg/tree for FA treatment, and 0.35 kg N + 0.23 kg P₂O₅ + 0.55 kg K₂O/tree for NR.

No significant yield difference was found between the two varieties in the irrigated area, however a significant effect of fertilization treatment was measured. The FA and NR treatments produced similar average yields (59 kg/tree) that was significantly higher compared to the FFP (9 kg/tree) and the control (12 kg/tree) yields. In the rain-fed areas, the highest average olive yields (43 kg per tree) were obtained when the fertilization program was based on FA and NR methods with no significant difference between the treatments. Olive yield under both FA and NR treatments was significantly higher than FFP (11 kg/tree) and the control (13 kg/tree) treatments. There was no significant difference in olive oil content between the fertilizer treatments in both the rainfed and irrigated areas.