Olive oil is a basic constituent of the Mediterranean diet. Consumption has significantly increased in the past few years owing to its nutritional value and recognized benefits for human health. Traditionally, olive (Olea europaea L.) is a tree species grown in arid environments, with little rainfall occurring during the periods of major plant water demands.
Many adaptive anatomical and physiological mechanisms allow it to withstand damage caused by drought stress reducing vegetative growth and yield performance.
Olive cultivation is steadily expanding throughout many countries, in response to increased oil consumption. Efforts are being made towards improving the agronomic practices aimed at increasing yields and reducing costs while maintaining oil quality without harming the environment.
Some of the technical targets include the reduction of alternate bearing and mechanizing cultivation and harvest. Under such schemes optimizing the water regime is essential for best tree growth and oil production while ensuring efficient water use by the crop.
Irrigation affects the olive yield, fruit size distribution (fresh weight and volume) and qualitative characteristics of the fruit. In addition to morphological and biochemical changes, soil water availability influences phenology and time of fruit maturation.
Today, throughout the Mediterranean region, it is common to find the conversion of traditionally raised rain fed olive orchards to irrigation in an effort to improve productivity. However, the availability of water for irrigation is decreasing due to increased alternative demands for water mainly by industry and households, high energy costs of pumping and distribution as well as decreased water quality.
Future scenarios predict that in most Mediterranean countries where olive cultivation is concentrated per capita, availability in 2025 will decrease by 50% with respect to 1987. Therefore, new innovative sustainable technologies are needed not only for raising and sustaining olive productivity per hectare but also to achieve a consistent supply of quality fruits.
Parallel to meeting a growing olive oil demand on an international level, the challenge for olives is to be competitive in the global market and be supplied at a lower cost while using scarce and expensive resources such as water and fertilizers.
Food and agro-industrial crop Climatic change and water scarcity concerns Rising fertilizer and labor costs Leaching and washing away of nutrients by runoff Low water and fertilizer use efficiency Low oil productivity per hectare under rain fed dry lands Promising crop and expanding market
Why is drip needed?
Economic importance of olives in meeting growing oil demand. Recognized health benefits. To conserve water, increase water and fertilizer use efficiency and optimize olive fruit and oil yields.
Name of the cooperative
Iksal irrigation cooperative
Location: Iksal irrigation cooparative, Iksal (32° 94′ 0″ N-latitude, 35° 08′ 0″ E-longitude), Afula, Israel
Area: 80 ha
Crop variety: Souri
Crop spacing: Row to row – 7.0 m and plant to plant – 8.0 m
Seed rate: 178 rooted cuttings/ha
Plant population at harvest: 178 trees/ha
Other related details
Year of planting: 1994;
irrigation commencement year: 2001;
crop age at the start of irrigation: 7 years;
harvesting season: End of October- end of December every year
Climate: Arid climate with hot summer and mild winter, frost free
Maximum temperature: 18 – 31°C
Minimum temperature: 9 – 21°C
Mean vapor pressure: 9 – 20 hPa
Mean wind speed: 6.2 – 11 km/hour
Sunshine duration: 2.4 – 9.4 hours
Rainfall: 641 mm/year; effective rainfall: 520 mm/year
Reference crop evapotranspiration: 1394 mm/year
Moisture availability index: -0.54
Other climate-related indicators: Aridity index: 0.46
Soil physical properties: Clayey soil texture
Soil pH: 7.9
Bulk density: 1.3 – 1.4 g/cm3
Water table: Below 6 m
Soil chemical properties: N (20 mg/kg), P (<5 mg/kg), K (2.5 meq/100 soil) Soil salinity (ECe): 1.95 dS/m
Waer source: National water carrier system
Power source: Gravity pressure
Agro-solution: What has been done?
Subsurface drip irrigation (SDI) system Head control unit, main and sub-main pipes besides Ram integral dripline 16 mm diameter, with a lateral spacing of 7.0 m, emitter spacing of 0.75 m and emitter flow rate 2.3 Liters/hour. Each tree row was irrigated by one dripline laid 1.0 m away from the tree trunk parallel to the rows below the soil 0.15 to 0.25 m depth. Year of drip system installation: 2001
Agronomic and technical support
Crop water requirement and irrigation scheduling: Depth and frequency of water application; water quality consideration and measurement of applied water.
Soil and water analysis, estimation of nutrient dose, selection of fertilizers and compatibility, application skill via drip system and foliar diagnosis for nutrient deficiencies. System operation and maintenance: Pressure reading, valves operation, measurement of applied water. Cleaning of filters, fertilizer tank, acid treatment, chlorination, etc. Training and capacity building: Soil water plant relationships, drip irrigation and fertigation principles, benefits, limitations and utility; water quality and herbicide usage.
Improved olive fruit yield: Conventional rain fed orchard – 4.6 tons/ha and with subsurface drip yield of olive fruit increased by 174% (12.6 tons/ha). Improved olive oil yield: Conventional rain fed orchard – 1.1 tons/ha and with subsurface drip yield of olive oil increased by 118% (2.4 tons/ha). Improved olive oil quality: Similar free fat acid (FFA), increase in fruitiness; and decreased bitterness and pungency in comparison to overhead sprinkler irrigation. Irrigation water requirement: Conventional rain fed, only rainfall, and with subsurface drip 3500 – 4000 m3/ha (350 – 400 mm/ha). Economic indices: Higher net returns by subsurface drip in comparison to rain fed crop. Additional benefits: Uniform canopy development, higher fruit size, improvement in fertilizer use efficiency, management flexibility, less weed growth and uniform irrigation of olives on undulated terrains.
Drip irrigation of rain fed traditional olive orchards in Israel is a feasible eco-technological and economically viable technological option. Use of scarce water resources in a sustainable way in olive farming brings larger area under olive cultivation. Higher productivity and fruit quality characteristics, edible oil security, health benefits and increased income for farmers. Olive best management practices – Subsurface drip irrigation (SDI) and Fertigation scheduling.
Grow More: 172% olive fruit and 115% oil olive yield
With Less: Fertilizers, weed and olive bitterness