Optimizing Irrigation Water Management on the Global Change Context in a Mediterranean Region

Optimizing Irrigation Water Management on the Global Change Context in a Mediterranean Region CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Objetive To analyse the impact of Water Framework Directive, the Common Agricultural Policy Reform and the Climate Change on the management, the productivity and the economic efficiency of irrigation at farm level. CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Location: Central Part of the Guadalquivir Valley Crop: Irrigated Grain Maize CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Methodology CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero Crop Data Irrigation Data Socioeconomic Data Climatic Data WADI Political Scenarios CAP+WFD Climate Change Scenarios DSSAT Model Hydraulic Irrigation Model Seasonal Economic Optimization Model GCM Model & Downscaling INTERFACE

Crop, Soil and Climatic Data CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

The model proposed by Allen et al. (1998) was used to calculate a daily water balance in the soil-plant-atmosphere complex. Potential and actual evapotranspiration were estimated by the method of dual crop coefficients, taking into account the water stress conditions. Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

A mathematical model was developed in order to simulate all phases (advance, storage, depletion and recession) of furrow irrigation with free runoff. For drip irrigation system modelling, an Application Efficiency of 90%, a drip discharge of 2.3 L/h and a density of 6666 drips/ha were assumed. Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

The Jensen’s model (Jensen, 1968) was used to estimate the actual crop yield: In order to relate the yield response factors Kyi , calibrated from DSSAT results, to the sensitivity index of Jensen’s model, a polynomial function proposed by Kipkorir and Raes (2002) was used. Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Dynamic Programming was implemented as the method for economic optimisation, in which each irrigation event was considered as a stage of the process. As objective function, the maximization of net profit of agricultural production was defined. Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

The irrigation optimisation model used the daily values of reference evapotranspiration calculated in DSSAT for each climatic data series.

Daily evolution of basal crop coefficient was determined as the relation between potential transpiration and reference evapotranspiration calculated by DSSAT model.

Successive DSSAT simulations were run, by introducing different water stress levels in every phase of crop development. The values of yield response factors Kyi were determined through lineal regression between the relative yield and the relative evapotranspiration obtained by DSSAT for each individual period of crop growth.

Integration: DSSAT Model and the Irrigation Optimisation Model CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

The climate change scenario forecasted for the year 2020 were taken from the CGCM2 model outputs, provided by the Canadian Centre for Climate Modelling and Analysis.

The IPCC SRES A2 scenario for greenhouse gases emissions (IPCC, 2001) was considered.

In order to downscaling the forecasted climatic data, the outputs of LARS-WG weather generator were perturbing according to the CGCM2 results.

Climate Change Scenario CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Agricultural and Water Policies Combined Scenarios CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Irrigation Modernization Scenarios CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero Basic Level Medium Level High Level

Climate Change and Crop Water Requirements CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Crop Production Function CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Net Profit, Economic Efficiency... CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Irrigation Management CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Conclusions

Climate change scenario used in this study predicted an increment of net irrigation requirements in 40.2 mm.

Maize production experimented a remarkable loss in profitability and economic efficiency in the context of agricultural and water policies induced by the Global Sustainability and World Markets scenarios.

The irrigation systems based on medium levels of modernization were able of assimilate the new paradigm that transposition of the Water Framework Directive, the revision of the CAP and the climate change supposed.

CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero

Optimizing Irrigation Water Management on the Global Change Context in a Mediterranean Region CONSEJERÍA DE AGRICULTURA Y PESCA Empresa Pública Desarrollo Agrario y Pesquero