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Moriana et al., 2GG6

Currently, no private farms exist that apply this technique. However, it is certain that, the maximum permissible irrigation set for certain crops, as well as, the offered recommendations of irrigation from the SIAR, consider these results to try to maximize the yields for that level of deficit. The clearest examples can be seen in the tree crops such as vineyard and the olive tree. In these crops, the curves of the Kc have been modified from the results obtained in the previous trials to reduce the recommendations of irrigation (Figure 24 and 25).

Kc Vineyard Kc evolution (var. Cencibel)

23/3 7/4 22/4 7/5 22/5 6/E 21/6 6/7 21/7 5/8 20/8 4/9 19/9 4/10 9/10 Date

Figure 24: Evolution of the Kc for the vineyard (cv. Cencibel) in the province of Ciudad Real (SIAR, 2007).

Kc Olive tree Kc evolution

23/3 7/4 22/4 7/5 22/5 6/E 21/6 6/7 21/7 5/8 20/8 4/9 19/9 4/10 9/10 Date

Figure 24: Evolution of the Kc for the vineyard (cv. Cencibel) in the province of Ciudad Real (SIAR, 2007).

Kc Olive tree Kc evolution

CM kfi CO

Date

Figure 25: Evolution of the Kc for the olive tree in the province of Albacete (SIAR, 2007).

The recommendations offered by the SIAR are evaluated in the field by means of the monitoring of several control plots. Given its growing importance in the region, a curve of Kc for the crop of pistachio is being developed.

3.3 Decision Support Systems Models

3.3.1 Economic Optimization Model for Irrigation Water Management (Modelo de Optimización Económica En La Agricultura de Regadío, MOPECO)

Many factors are involved in irrigation management, including water availability, product prices and market uncertainties, plus the constraints imposed by agrarian policies. All of these factors should be considered when designing an irrigation schedule. Through SIAR, CREA uses the MOPECO decision-making tool (Ortega et al., 2004a) to assist farmers in the development of irrigation strategies, while also determining correct depths of applied water, in order to economically optimize water use. Conventional irrigation management strategies are usually planned without deficit irrigation, even though the economical optimum will imply some degree of under-irrigation, depending on the crop, its water requirements and gross margin (Tarjuelo and de Juan, 1999; Ortega et al., 2004a). The MOPECO model is composed of two computing models:

Module I determines "Yield vs. Gross irrigation depth" for each crop and "Gross margin vs. Gross irrigation depth" functions (Figure 26).

Crop data

Maximum yield Stages duration Root depth Kc Ky ET group

Irrigation Management ETa/ETm objective

Daily climatic data

Climatic station data Effective rainfall (%)

Function

Gross margin vs. Gross irrigation depth

Figure 26: Module i sketch.

Crop data

Maximum yield Stages duration Root depth Kc Ky ET group

Daily ETo

Daily ETo

Irrigation Management ETa/ETm objective

Daily climatic data

Climatic station data Effective rainfall (%)

Function

Gross margin vs. Gross irrigation depth

Module II determines the distribution of crops that obtain the maximum gross margin (Figure 27).

Crops restrictions

Maximum irrigated area Maximum gross irrigation depth Max. and Min. set-aside area

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Farm restrictions

Maximum irrigated area Available volume for irrigation

-Optimizer -

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