Objective:
To conduct research on the reuse of low-quality sources of water for irrigating high value fruit tree orchards. Olives are a natural candidate for utilization of low quality and recycled water, as they are considered moderately tolerant to salinity and highly tolerant to boron. The Research Objectives are: 1) demonstrate the potential of recycled water for olive irrigation; 2) evaluate the water requirements for olives; 3) determine effects of deficit irrigation on growth and production of olives; 4) develop irrigation regimes for efficient water management of olives based on potential evapotranspiration measurements and development of appropriate crop factors; 5) analyze monitoring methodology for water status and stress of irrigated olives.

Approach:
1. Collect meteorological data (wind speed; radiation; temperature (air and soil); relative humidity; rain) generated at the project site will be used to compare methods of calculating ETp (modified ¿Penman-Montheith¿ type ETp calculations and ¿Class A¿ pan measurements). 2. Water application quantities measured as percent return of ET will be compared to quantify effect of irrigation water quantity on growth of olive trees, yield and quality of oil produced. 3. Research will be conducted in a commercial olive orchard with general up-keep and horticultural practices in accordance with accepted commercial practice. The orchard will be drip-irrigated with local reclaimed wastewater. Continue application of the irrigation treatments; equivalent to 30, 50, 80, 100 and 120% of ETp (ETp X cover factor) to the two olive cultivars, 'Barnea' and `Souri¿, in accordance to experimental design of the year one. 4. Treatments will be given to blocks of 12 trees (3 rows X 4 trees). The statistical design will be randomized complete-block with six replicates per treatment. Each of the 60 experimental units will consist of three adjacent tree rows with 4 olive trees per row. The center 2 trees will be monitored while those surrounding will serve as border-guard trees. 5. Soil water potential will be monitored at three depths (30, 60 and 90 cm), below emitters using continuous-logged tensiometers at a single site for each treatment. Plant water status will be assessed 4 times during the irrigation season (April- October) by mid-day leaf water potential using a Scholander-type pressure chamber. 6. Mineral content of diagnostic leaves will be analyzed twice a year (mid- summer and mid-winter). Soil will be sampled under the emitter lateral twice (end of winter-March and September) and evaluated for water content. Saturated paste extracts from the soil samples will be analyzed for electrical conductivity, for nutrient concentrations and for concentrations of salt ions. Seasonal shoot growth will be evaluated in 4 shoots in each of the monitored trees (two per replicate) by measuring a labeled young shoot each year during April and September. 7. Each variety will be harvested according to its appropriate ripening stage. Yield will be determined for each monitored tree. Oil percentage will be measured in each replicate by chemical extraction. A sample of oil will be extracted from each replicate in a mill suitable for small quantities. Chemical quality parameters to be tested include: FFA (free fatty acids) and their composition; peroxide value; and UV absorbance. Total polyphenols will be measured in order to determine oil stability. Organoleptic quality testing will be conducted to determine both positive and negative aesthetic attributes.