Strategic Approaches to Integrated Management of Land, Water and Livelihoods along an Aridity Gradient: Southern Tunisia site Regional Knowledge Exchange on Decision-support Tools and Models to Project Improved Strategies for Integrated Management of Land, Water and Livelihoods September, 2013, Djerba, Tunisia

Team BiophysicalSocio-Economic H. KhatteliM. Sghaier M. OuessarM. Abdeladhim K. NagazR. Bechir M. Ben Zaied A. Zerrim F. El Mokh A. Hachani

S1 (North): Tunis (semi arid) S2 (Centre): Sidi Bouzid/Kasserine (semi arid) S3 (South) : Medenine/Tataouine (arid) Study sites in Tunisia S1 S2 S3

Wadi Hallouf/Oum Zessar watersheds, Medenine Transect stretching from Plateau of Dhahar to the Gulf of Gabès (Mediterranean sea): 3 main basins: wadis of Hallouf, Oum Oum Zessar, Oum Ettamr). Area: around 1500 km2. Rainfall ranges between 160 mm (east, plain of Jeffara), 200 mm (central part, mountain of Beli Khedache) and less than 100 mm (west, plateau of Dhahar). Land use: East: olives, small scale irrigation; Central: fruit trees behind water harvesting structures; West: rangelands. Population: around inhabitants

MODELLING OLIVE GROVES VULNERABILITY TO CC

Images Landsat 5 and 7 Soil map Land use map HidroMOREHidroMORE NDVI Conceptuel Model Geométric and atmospheric correction climatic data: Baseline period, until 2030 and until 2090 collecting data Treatement 9

41 Slightly suitableModerately suitable suitable Baseline period28%46%26% Horizon %68%13% Horizon %76%0

GABION CHECK DAMS EFFICIENCY

WATER MANAGEMENT IN THE IRRIGATED AREA

Actions 1- Evaluation of on-farm irrigation scheduling of drip irrigated vegetable crops under arid conditions of Tunisia 2- Deficit irrigation of orchards : case study of citrus trees Location - Bedoui & Megarine in the arid part (R: 150 mm & ETo: 1500 mm)

Pilot site: Evaluation of on-farm irrigation scheduling of drip irrigated vegetable crops under arid conditions of Tunisia. - Water source: private shallow well having an ECi of about 5.8 dS/m, flow rate ranging between 3-4 l/s and a depth less than 35 m - Soil: Sandy soil texture (Clay: 6.77%, Loam: 12.68% & Sand: 80.55%) having low organic manure (<0.8%) - Vegetable crops: potato, carrot, green bean and pepper - Irrigation system: Drip irrigation method

Irrigation scheduling methods Two irrigation treatments based on the use SWB to estimate irrigation amounts and timing were compared to traditional farmer practice. Field monitoring Soil salinity and water content Ground canopy cover, stomatal conductance Yield and its components at physiological maturity Water supplies (I+R) (using water meter and rain gauge) Water productivity (WP) WP (kg/m3) = Yield (kg/ha) / irrigation water (m3/ha)

Results First year of experiment Data collected on Potato, carrot & green bean, Pepper experiment is still in progress

Pilot site Megarine: Irrigated field (55ha) with relatively fresh water (1-1.5 g/l) from a tube well. Pilot site serve testing technical itinerary for fruit trees Field experiments on improved water productivity by deficit irrigation and irrigation scheduling: Implications for saving water in citrus orchards Experiments in a drip irrigated citrus orchards are actually launched in the zone of Megarine, Médenine. (12 years-old ‘Meski Maltaise trees grafted on Bigaradier with tree spacing of 7x6 m) Four drip emitters per tree (4 l/h) connected to a double drip line, two per side of the tree, are used in the experiment

Pilot site: Improved water productivity by deficit irrigation and irrigation scheduling: Implications for saving water in citrus orchards

Irrigation treatments - Control treatment (FI-100) irrigated at 100% of - The DI treatments irrigtaed at 75 and 50% of ET (DI-75, DI-50) - FM irrigated according to farmer irrigation practice FM, DI & FI implemented during the active period of citrus corresponding to different phenological stages (flowering and initial fruit set, fruit growth, and maturity) and post- harvest For citrus experiment Irrigation strategies will be evaluated according to their impact on: - amount of irrigation water saving - vegetative growth (diameter fruits) - stomatal conductance - yield, fruit size, total soluble solids (°Brix) - water productivity - soil salinity

MPDELLING CLIMATE CHANGE IMPACT AND ADAPTATION STRATEGY ASSESSMENT ON CROP PRODUCTION

- Selected crop : potato - Model selection: Aqacrop - Meteorological data Médenine station Climate scenarios Minimum and maximum temperature and rainfall projections will be used as input for t the AquaCrop model and to estimate the future ETo using the FAO tool EToCalculator. - Modelling the impact of climate change on crop yield - Calibration and Validation of AquaCrop for Potato Field experiments ( ) in Médenine region Calibration and validation of the model Collection of weather data, soil characteristics and management inputs Calibration on basis of observed soil water content, biomass, yield and canopy cover Calibration by adjusting the crop input file Model validation is in progress - Model simulation After model calibration and validation, the model will be used to determine the impact of climate change through simulation of biomass and yields over periods. -

- Modelling the impact of climate change on crop yield Input data for AquaCrop obtained from the mean minimum and maximum air temperatures and total rainfall data from the downscaled GCM data sets, and reference evapotranspiration values). The AquaCrop model to predict potato yields under the following conditions: Current situation (simulate actual yields) ( ) Impact ( ): Projected climate for three time periods of ten years: , and (simulate yields under climate change scenarios) Adaptation scenarios ( ): Projected climate using recommended adaptation strategy i.e. DI/SI using the AquaCrop model

AGRO-SOCIO-ECONOMICS

Activity 4: Livelihood and quantification of benefits in terms of enhanced benefit/cost ratio The technico-socio-economic data-base is being under construction :Household Characteristics ; Livelihood strategy (Human Assets, Natural Assets, Physical assets (farm capital), Financial assets (farmer’s income and expenditure), Social assets); Farming system characteristics and Land resources ; Water harvesting techniques ; Resources bases (sources of water for agriculture). Household survey and data collection 139 Household’s surveys have been finalized in the study area. The aims of these technico-socio-economic surveys are to provide data for the three activities; Since the study site is a Watershed, the sample of the interviewed households was homogeneously distributed from up-stream to the down-stream area.

Activity 4: Livelihood and quantification of benefits in terms of enhanced benefit/cost ratio 104 complementary technico-socio economic surveys have been finalized in the study area (June-September 2013) : 74 surveys in the upstream and piedmont and 30 in the downstream area) The aims of these technico-socio-economic surveys are to calculate WLI indicators : Agricultural land (cultivated area and area under improved practices, gross margin per ha for target crops, on farm income, household income. The On-farm income and the Gross Margin Per Hectare will be calculated using the WLI approach.

Activity 4: Livelihood and quantification of benefits in terms of enhanced benefit/cost ratio Calculation and analysis of two type set of indicators: Indicators previously identified by WLI Tunisia team identified under the Sustainable Livelihoods Framework, (five types of asset: human capital, social capital, natural capital, physical capital, and financial capital); Most of the WLI 2012 indicators : Agricultural land (cultivated area and area under improved practices, gross margin per ha for target crops, on farm income, household income. The On-farm income and the Gross Margin Per Hectare will be calculated using the WLI approach. In parallel, there was also the collection of secondary data from technical services and regional statistics in order to characterize gross income (margin) per hectare for dominant crops (olives, figs, cereals, legumes etc.) and on other indicators in SLF in the watershed of Oum Zessar.

Starting of review of available methodologies and assessment frameworks and consultation of colleagues concerning water-related agroecosystem services to be quantified, Organization of a stakeholder’s workshop (13-14 June, 2013) in order to start discussion about scenarios (local development scenarios and climate scenarios) to be presented for discussion during the next Multi-stakeholders workshop (decision makers, scientists and actors). Economic assessment of climate change effects on agro-ecosystems

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