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Figure 13: Bottom water flux (positive downwards) during the crop irrigation period at current and 2025 climate conditions. Vertical bars indicate ETc variability.

As shown in Figure 11, average water looses in 2025 are lower than in current conditions. Sugarbeet maximum evapotranspirations will be higher in the future and hence the crop will use some of the water that is currently percolating. This relative increment of the water-use efficiency of the current irrigation management would be more evident during the first crop growing stages, as well as during the tuber formation period.

However, in the same way than the actual evapotranspiration shown in Figure 12, the water loosing variability will be much higher in the future. The variability is extremely large during the first crop-growing phases. Rainfall variability and temperature extremes are expected one of the most important consequences of Climate Change for the first half of the XXI century (IPCC, 2007; EC, 2007). It would have a significant effect in the water-use efficiency of the currently considered irrigation water managements.

Introducing Climate and Crop-Growth Simulation Tool to Support Agricultural Decision-Making: The "Users" Point of View

"Users" and "Developers" were invited to the final AGRIDEMA workshop, which was held in Valladolid, Spain, middle 2007. The results of the assessments report were presented, focusing on the "users" points of view regarding the limitations of the available climate and crop-growth modeling tools. Hence, the "developers" received a feedback on how to improve the corresponding tools. Furthermore, the "developers" also pointed out the current development of the tools. Some representatives of farmer organizations, insurance companies and policy makers were also present.

AGRIDEMA interactions between "Users" and "developers" yielded some interesting results. Regarding the GCM outputs, "users" complained on the data format and the time scale. Only the Canadian CCCMa model provides daily data in an easily-converted format, through a Web service. This became such model as the most used in the AGRIDEMA

framework. Besides, "Users" request to the national meteorological services to provide statistical (and/or) dynamical downscaled data of the most relevant GCM and emission scenarios. Such data can be used at each country in climate-change agricultural applications. Some of the "Users" and particularly the farmer representatives argue about the utility of RCM data, since the 2070-2100 seems to be extremely far for practical medium-term assessments. Farmers are mainly interested on seasonal or short-term applications. Furthermore, market prices, CAP, WFD and European or national policies can significantly influence farmer decision, besides of climate conditions. Particularly, CAP cross-compliance and the rural development funds can be an important instrument to introduce and evaluate climate-change adaptation measures in the European agriculture.

Concerning the weather generators, "Users" from the Mediterranean region pointed out that the main current approach, based on generating the variables needed for Priestly and Taylor evapotranspiration approach might not be useful. The Penman-Monteith approach has been largely recognized as the most adequate in dry conditions. "Users" took note about the facilities provided through the EU proposal ENSEMBLES. The availability of downscaled data from seasonal forecast and decadal scenarios could be an important encouragement for climate-risk agricultural assessments.

According to the AGRIDEMA results, DSSAT, WOFOST and CROPSYST are the most relevant crop-growth simulation models that are being used in Europe for climate-change risk assessments. The utility of crop models to support agricultural decision-making has been recognized. However, the "cascade approach" considered in many models to simulate soil water balance might be not adequate. This approach ignores capillary rising, which might be important in rainfed or deficit irrigation crop systems.

The AGRIDEMA participants strongly encouraged Universities and Educational politicians to held courses of current climate and crop-growth simulation tools. These tools are still unknown by most of their potential "Users", which has been considered as the main current limitation to introduce them in practice. Besides, they encourage also conducting demonstration proposals, addressed to calibrate and validate the simulation tools in several farm conditions. FP7 cooperation program aims to increase private investment rates in R+D in Europe. The demonstration proposals, funded by FP7, could count on farmers and agribusiness since they are interested in adopting reliable measures in order to reduce climate risks. The participation of agricultural applied-research or extension services in those proposals is crucial.

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