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

This experiment started in 2014 with the objective to assess the effect of improved methods for nutrients recommendations in olive orchards in Morocco. Two on-farm experimental sites were selected with olive orchards in irrigated and rainfed areas of Marrakech and Essaouira provinces, respectively. The planting density was 204 and 25 trees/ha at irrigated and rainfed sites respectively. At each site, four treatments were used including: 1) plots without additional fertilization (control), 2) farmer fertilizer practice (FFP), 3) fertilization based on nutrient removal, and 4) fertilization based on foliar analysis. In the irrigated area, applied fertilizers were 0.66 kg N/tree in FFP; 0.46 kg N + 0.3 kg P₂O₅ + 0.36 kg K₂O/tree for the foliar analysis treatment; and 0.51 kg N + 0.20 kg P₂O₅ + 0.43 kg K₂O/tree for the nutrient removal treatment. In the rainfed area, applied fertilizers were: FFP (no additional fertilizers were applied by farmer); 0.24 kg N + 0.20 kg P₂O₅ + 0.50 K₂O kg/tree for the foliar analysis treatment; and 0.35 kg N + 0.20 kg P₂O₅ + 0.45 kg K₂O/tree for the nutrient removal treatment.

In both the irrigated and rainfed areas, the highest olive yields per tree were obtained when the fertilization program was based on foliar analysis. In irrigated olive orchards, the foliar analysis method produced the highest olive yield (59.7 kg/tree), which was 8.6 kg/tree, 11 kg/tree, and 26.4 kg/tree higher than the olive yields obtained with the nutrient removal method, FFP, and the control, respectively. In the rainfed olive orchard, foliar analysis produced an average olive yield of 125 kg/tree, which was 15 kg/tree, 46 kg/tree, and 48 kg/tree higher than the olive yields obtained by the nutrient removal method, FFP, and the control, respectively. In terms of olive oil content, no significant difference was observed between the foliar analysis and nutrient removal methods in irrigated olive orchards (average of 48.7%); however in the rainfed area, olive oil content was significantly higher under the nutrient removal method (43.6%) compared to the foliar analysis method (41.8%).