Response of Mature Olive Trees - Switching from Conventional to Drip Irrigation

1. Response of mature olive trees to switching from
conventional to drip irrigation in dry area of Morocco-
Assessment of fruit and oil quality and composition
Abderaouf El Antari(1,*), Lhassane Sikaoui(1), Abdelaziz Bouizgaren(1),
Mohammed Karrou(2), Hakim Boulal(2), Mohammed Idrissi(1), Yamna
Ouguas(1), Vinay Nangia(3), Theib Oweis(3)
(1) INRA, CRRA Marrakech, BP 533 Morocco
(2) ICARDA, Rabat, Morocco
(3) ICARDA, Amman, Jordan

2. In Morocco, the area of irrigated olive trees increased in
the last decades to reach 35% of a total of around one
million hectares.
Most of this irrigated area is cultivated under traditional
inefficient surface irrigation system.
To overcome this inefficiency of water use, new saving
irrigation methods such as drip irrigation have been
promoted by the Government.

3. The objective of this research is to study the response of
mature olive trees to switching from conventional to drip
irrigation.

4. For this purpose :
 A trial was conducted in a 36-years old irrigated olive
orchard (var. Picholine marocaine) at the Tessaout
experiment station of INRA Marrakech characterized by a
hot and dry summer Mediterranean climate.
 Five treatments are tested :
T1= Flood irrigation (farmer’s use)
T2= Minimum tillage with drip irrigation (100% x ETc)
T3= Minimum tillage with drip irrigation (70% x ETc)
T4= Deep tillage with drip irrigation (100% x ETc)
T5= Deep tillage with drip irrigation (70% x ETc)

5. Estimated fruit yield under the five studied treatments.

6. Olive average weight under the five studied treatments.

7. Maturity index of olives under the five studied treatments
Treatments Maturity index
T1 (Flood irrigation) 2.2 b
T2 (Min Till 100 % ETc) 3.04 a
T3 (Min Till 70 % ETc) 2.87 a
T4 (Deep till 100 % ETc ) 2.94 a
T5 (Deep till 70 % ETc ) 2.69 a

8. Oil yield (Kg/Ha) of olives under studied treatments
Treatments Maturity index
Oil yield
(Kg/Ha)
T1 (Flood irrigation) 2.2 b 1244,0
T2 (Min Till 100 % ETc) 3.04 a 1531,4
T3 (Min Till 70 % ETc) 2.87 a 1607,0

9. Treatments Viscosity (%)
Color index
L* a* b*
T1 (Flood irrigation) 3.27 ab 69.79 -6.58 46.77
T2 (Min Till 100 % ETc) 3.44 ab 54.68 -3.02 28.19
T3 (Min Till 70 % ETc) 3.82 b 59.82 0.14 15.02
T4 (Deep till 100 % ETc ) 3.72 ab 38.62 -0.03 23.75
T5 (Deep till 70 % ETc ) 3.16 a 36.23 0.18 21.94
Viscosity and color index of olive oils obtained under studied treatments.

10. Treatments E232 E270
Oil
bitterness
Total poly-phenols
(ppm)
T1 (Flood irrigation) 1.41 0.106 0.900 292.46
T2 (Min Till 100 % ETc) 1.56 0.091 0.540 236.96
T3 (Min Till 70 % ETc) 1.60 0.103 0.510 222.83
T4 (Deep till 100 % ETc ) 1.54 0.087 0.464 183.80
T5 (Deep till 70 % ETc ) 1.43 0.092 0.554 201.97
Specific extinction, bitterness and total poly-phenols of
olive oils obtained under studied treatments.

11. Treatments
C16:0 C16:1 C18:0 C18:1 C18:2 C18:3 Mono/Poly
T1 (Flood irrigation)
9.83 0.57 2.62 74.05 11.31 0.97 6.10
T2 (Min Till 100 %
ETc)
9.85 0.57 2.83 73.38 11.82 0.95 5.87
T3 (Min Till 70 %
ETc)
10.14 0.62 2.47 73.78 11.33 1.00 6.13
T4 (Deep till 100 %
ETc )
9.86 0.57 1.81 75.02 11.10 0.99 6.29
T5 (Deep till 70 %
ETc )
9.77 0.57 2.21 75.67 10.11 0.98 6.91
Mayor fatty acids content of olive oils obtained
under studied treatments

12. Sensoriel profils of positif attributs under
deficit and full irrigation

13. Specific aromatic profils under deficit and
full irrigation

14. Hedonic test
The organoleptic quality of extracted olive oils was tested
by 60 farmers in a hedonic test :
80% of participants had appreciated and prefered oil produced
under deficit irrigation.

15. Conclusion 1/2
 highest olive fruit yield and fruit olive weight were obtained under
deep tillage and deficit irrigation.
 maturity index was shown no significant effect between minimum
and deep tillage, and between full and deficit irrigation
 olive oils from the various treatments were quite viscous and the
higher values were obtained under minimum tillage with deficit drip
irrigation (T3).
 No significant effect of oil color index was noted between studied
treatments
 The specific extinction values indicated that olive oils obtained
under all studied treatments had a high potential stability

16. Conclusion 2/2
 the high values of total phenols content and bitterness were
obtained with flood irrigation treatment (T1).
 The composition of the total fatty acids of olive oils did not show
significant differences among studied treatments.
 sensory evaluation of olive oil indicated that under deficit irrigation
(70% x ETc), the expression of sensorial positive attributes was more
intense and the specific aromas were clear with a good expression,
harmony and complexity of attributes.
 80% of participants in hedonic test had appreciated and preferred
oil produced under deficit irrigation

17. Thank you