1. Working Group 2 Report Introduction Definition of terms Water Use Efficiency related to Water Productivity WUE as a ratio; WP related to production or value

2. Water Use Efficiency Definitions as defined in presentations of Working Group 2 members during the Wasamed Workshop 30.09. – 04.10.05

3. Water Use Efficiency DefinitionsAdditionsUsed by Above- ground Biomass WUE = Above-ground Biomass (kg)M. Todorovic et al. (E)T c (m 3 ) Yield WUE = Yield (kg)M. Todorovic et al. (E)T c (m 3 ) WUE g,b (kg/m 3 ) =Yield or biomass (kg/m 2 ) Subscripts g, and b indicate grain yield and biomass Karaa et al. ET (m 3 /m 2 ) WUE and System efficiency level of the source, conveyance and storage of water, and on the farm level Nofall et al. Water application efficiency Water conveyance and distribution efficiency Aggelides et al WUE= Crop Yield Blümling et al. (Evapo-)Transpiration Classical efficiency = Rootzone storage Blümling et al. Main System Supply WUE-Terms and Definitions

4. WUE definitionsAdditionsUsed by Intrinsic WUE = A (CO 2 exchange rate) denotes the efficiency of each stomatal conductance unit in relation to assimilation of CO 2 Bort el al. Stomatal conductance to water vapour (9) Gas exchange WUE (instantaneous) = A (mmol CO 2 ) represents the amount of transpired water per assimilated CO 2 Used at leaf level T (mol H 2 O) Instantaneous WUE (corrected) = (Photosynthesis + Dark Respiration) Used at the level of the ear Transpiration rate WUE biomass (integrated) =Accumulated Dry Matter(kg) Used at plant level H 2 O transpired Crop WUE (water productivity) grain yield Used at crop level H 2 O evapotranspired

5. WUE-Definitions WUE definitionsAdditionsUsed by Physical (absolute) efficiency = using the least possible amount of water Hydrological/engineering approach: focuses on the way to divert water sources to satisfy all demand using less water Billi et al. Economic efficiency: =derive the maximum net benefit to society Economic approach: focuses on costs and values to balance supply and demand Economic indicators and indices of water use efficiency combine physical and economic data and also account for multi-period relationships. Institutional efficiency = assess the functioning of an institution regarding water Policy-related indicators of water use account for how water is used to meet social goals (ex: poverty alleviation) Environmental efficiency =optimal natural resource conservation Technological efficiency extracting more valuable products for the same amount of inputs

6. WUE-Chain WUE definitionsUsed by Gate Reservoir = Reservoir output x farmgate x field x root Reservoir input x reservoir output x farmgate x field Harvest Rootzone = W ET X W transp X m C02 assim. X m plant X harvestHsiao et al. W rootzone X W ET X W transp. X m C02 assim X plant Overall Consumpt. Transpiration Assimilation Biomass Harvest efficiency Efficiency Efficiency Efficiency Efficiency Efficiency

7. Water Productivity Definitions as defined in presentations of Working Group 2 members during the Wasamed Workshop 30.09. – 04.10.05

8. Water Productivity DefinitionsAdditionsUsed by WP= Crop Yield (kg) or Value (€) Fereres Water used (m 3 ) IWP = (kg)Fereres (m 3 ) Marginal WP = Value (€)Fereres Water used (m 3 ) WP = Revenues ($)P. Polycarpou 1(m 3 ) of water WP = Grain yieldBort et al. evapotranspiration WP=Output (US$)Nofal et al. unit of water (m 3 ) WP-Terms and Definitions

9. Water Productivity DefinitionsAdditionsUsed by WP Billi et al Profit per unit of water consumed Billi et al Crop WP = (kg) The eco-physiological aspects of WUE and WP -> crop water productivity Aggelides (m 3 ) Agricultural WP = (Value of the produce + value of the outflow) Blümling et al. Available water (unit)    m j Wj W Q Zj PR 1    time tdmt RFWD PA PUW,,

10. Definitions agreed (research focus) Biomass WP=Biomass/Etc Yield WP=Yield/Etc Socio-economic WP=Value/Etc

11. Definitions agreed (management focus) Yield WP = yield/IWU Socio-economic WP = values/IWU Denominator is scale-dependent

12. WUE definitions through the water efficiency chain (based on Hsiao) WUE definitionsUsed by Gate Reservoir = Reservoir output x farmgate x field x root Reservoir input x reservoir output x farmgate x field Harvest Rootzone = W ET X W transp X m C02 assim. X m plant X harvestHsiao et al. W rootzone X W ET X W transp. X m C02 assim X plant Overall Consumpt. Transpiration Assimilation Biomass Harvest efficiency Efficiency Efficiency Efficiency Efficiency Efficiency

13. Other indicators Irrigated/irrigable land ratio, to be considered at farm, basin and country scale (depends on water availability and cropping pattern and management practices) Water used in agriculture/total water use Volume of water available for irrigation /irrigable land Volume of water used in irrigation/irrigated land

14. Other indicators IndicatorRelation to sustainability Irrigated/irrigable land ratio, to be considered at farm, basin and country scale (depends on water availability and cropping pattern and management practices Institutional aspect Water used in agriculture/total water useSocietal aspect Volume of water available for irrigation /irrigable land Productivity aspect Volume of water used in irrigation/irrigated land Efficiency aspect

15. Recommendations To develop guidelines (tool box) for: 1)the quantitative assessment of WUE and WP 2) deficit irrigation of various crops based on the sensitivity to water stress at different growing stages To emphasize the needs of farmers in the WP assessments