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Subsequent to the approval of the PNR, the JCCM has developed two new plans of action in the improvement and transformation of new irrigations in CLM. Both plans appear in the Decreto 95/2000 and in the Orden 28-07-2004.

The irrigable policy adhered to by the JCCM in the second period is the following:

• Improvement and consolidation of existing irrigations by means of the modernization of infrastructure.

• Optimization of the management of water resources by directly involving users.

• The creation of new irrigations that fulfill the following requirements: to have resources assigned in the corresponding Hydrological Plan; to adhere to the regional proposal of the PNR; edafoclimatic conditions of the zone must be adequate; and they are oriented towards traditional tree and herbaceous crops of low water consumption, within the guidelines of the CAP.

In this manner, the JCCM determines the priority of the different irrigable areas in the region that are capable of entering into the program of transformation, improvement and irrigation modernization.

3.2 Irrigation Water Management

3.2.1 The Irrigation Advisory Services

IAS services can play an important role in assisting users in adopting new techniques and technologies to increase productivity (economic or social), minimizing environmental risks and contributing to the sustainability of the agrarian sector (Smith and Muñoz, 2002). Such services can be provided by private companies, public or co-operative agencies. Financial sustainability is the critical point in the promotion of irrigation advisory services.

In CLM, two IAS exist for the irrigators. The first in operation was the Servicio de Asesoramiento al Regante (SAR) (1987), coordinated by the ITAP and directed by the Delegation of Albacete. Consequently, its application scope is provincial, and mainly advises the irrigators of HU 08.29. In 1999, the Servicio Integral de Asesoramiento al Regante (SIAR) was put into effect for the rest of the territorial scope of CLM, because of the importance a service such as this contributes to the region. SIAR is coordinated by the CREA of the UCLM and directed by the Regional Department of Agriculture, which is in charge of the general guidelines, promoting contact with farmers and providing meteorological data. Both services have similar theoretical foundations and their schemes of operation are similar. For this reason, only the SIAR is described.

The Irrigation Advisory Service of Castilla-La Mancha (El Servicio Integral de Asesoramiento al Regante de Castilla-La Mancha, SIAR)

The overall SIAR objective is to help farmers to achieve an efficient use of their tools of production, especially water, fertilizers and energy. Appropriate scientific and technical support is provided to farmers in order to optimize management, making agriculture a sustainable activity compatible with the environment.

SIAR acts in coordination with the farmers, having them participate in the suggestion of solutions to problems and providing useful feed-back. SIAR contributes as much as possible to farmers' capacity building, so that they can develop the tools required to make business-oriented decisions in the management of their farms. This initiative aims to channel technology to irrigated agriculture, bearing in mind the relevance of local experience, and also considering the divergence between research results and farmers' practices.

Some of SIAR's key activities for achieving an efficient and economic use of water for irrigation (English et al., 1990; Ortega et al., 1997; Taijuelo and de Juan, 1999; English, 2002; and Ortega et al., 2004a) are as follows:

• Irrigation scheduling. The timing and volume of irrigation must be specified according to standard scheduling criteria.

• Distribution network and on-farm irrigation systems. Both levels must be correctly designed, maintained and managed to achieve high-irrigation performance.

• Crop rotations to maximize the gross margin. Since agriculture is an economic activity, it is important to maximize water profitability. Water management plans must include deficit irrigation strategies, searching for maximum gross margin instead of maximum yield.

The following sections describe these activities in depth.

In order to develop these tasks, a multidisciplinary scientific team is available (agricultural engineers, hydrogeologists, electronic engineers, computer specialists, and economists). Together with researchers, a field engineer's team is in charge of collecting field data, providing information to farmers, and performing irrigation system evaluations.

The areas where SIAR operates are presented in Figure 18. These areas represent the main irrigated production systems in the region. The areas are strategically distributed to achieve a demonstration effect of the SIAR in the entire CLM region. All the pilot areas of SIAR are water-limited, except for those in Toledo and Guadalajara.

Figure 18: Pilot areas of SIAR.

There are several methods by which to disseminate information generated by SIAR:

• Internet. The information is available on the Internet through the web site of "Junta de Comunidades de Castilla-La Mancha" (http://www.jccm.es) or the CREA (http://crea.uclm.es) (Figure 19). Among the information provided on the web, the most valued by farmers is related to crop water requirements. Figure 20 presents an example of requirements published weekly in an area (Daimiel). The site includes other information, the most important being, fertilization advice and regional meteorological data.

Figure 19: Access page to SIAR of Castilla-La Mancha in the web site of JCCM.
Figure 20: Example of "water requirement" data corresponding to the irrigable area of Daimiel (Ciudad Real).

• Facsimile. Sending weekly information by fax to farmers. Farmers associations and cooperatives often use this method of dissemination. Managers have the responsibility of making this information available to their associates.

• Workshops. Informational workshops to present SIAR and to present to users the catalogue of available services.

• Communication media (newspapers, radio and local television). This method of information distribution has been employed to inform people of the activities of the SIAR.

The achievement of recommended water requirements, by farmers, has been very satisfactory. In the new pilot areas where the SIAR was applied in the 2000-2006 seasons, farmers have steadily increased their response to recommendations. About 360 farmers from all pilot areas directly collaborate with SIAR (Fig. 21) in the monitoring of their farms (crops, yields, water application, etc.). More than 1200 farmers receive irrigation advice, mainly through associations (irrigation districts, or cooperatives), and about 20% of the irrigated land in CLM (100,000 ha) benefits from SIAR irrigation advice.

There are great differences in the follow-up of irrigation scheduling among different pilot areas (Fig. 21). In all pilot areas where resources are scarce and application costs are high, the adherence to the irrigation advice is also high. In the pilot areas of the Tajo basin (Toledo and Guadalajara provinces) where water is not as restricted (farmers pay for the irrigation water by area instead of by volume), the adherence of SIAR is low. However, even these farmers resort to SIAR for consultations related to crop management or specific problems in their irrigation systems.

Albacete Ciudad Real Cuenca Guadalajara Toledo Castilla-La

Mancha

Figure 21: Progression in number of farmers who collaborate with SIAR in the action areas.

Albacete Ciudad Real Cuenca Guadalajara Toledo Castilla-La

Mancha

Figure 21: Progression in number of farmers who collaborate with SIAR in the action areas.

3.2.2 Water Requirements and Irrigation Scheduling

The methodology used to determine the irrigation requirements and irrigation scheduling is based on the FAO guidelines, taking into account the simplified daily water balance in the soil-plant-atmosphere set (Doorenbos and Pruit, 1992; Allen et al., 1998; and Pereira and Allen, 1999). The estimation procedure begins with the determination of reference evapotranspiration (ETo) and ends with the water balance, considering soil water content, the irrigation timing and the resulting gross irrigation depth.

ETo is calculated using the Penman-Monteith method (Pereira and Allen, 1999). This methodology, generally accepted in the literature for semi-arid areas, has been validated for local conditions by means of measurements in weighting lysimeters (Lopez Urrea, 2004). A 43 automated weather stations network has the sensors to calculate the ETo by means of the aforementioned method.

The crop ET (ETm) for different crops in each one of the pilot areas is determined from the crop coefficient (Kc) curve, and is established based on the literature and experience in the area (Doorenbos and Pruitt, 1992; Martin de Santa Olalla et al., 1992; Martin de Santa Olalla et al., 1994; Allen et al., 1994; Allen et al., 1998; Fabeiro et al., 2001; and Ortega et al., 2004b).

Table 14 shows the crops for which the water necessities are calculated in each one of the zones of study.

Table 14: Advisored crops by the SIAR.

Herbaceous crops

Horticulture crops

Tree crops

Alfalfa

Maize

Poppy

Melon

Onion

Pepper

Potato

Tomato

Garlic Green bean

Olive Peach Plum

Almond Apricot

Sugarbeet Sunflower

Wheat Wicker

Vineyard

Watermelon

In the other hand, ITAP has a lysimeter station consisting of three continuous weighing lysimeters with electronic data reading. Each of them is surrounded by a square protection plot of one hectare (Fig. 22). One of them is sewn with grass (Festuca Festuca arundinacea Schreb) and kept under ideal growth conditions with the aim of obtaining reference evapotranspiration values (ETo). Next to this lysimeter, there is an agro climatic station that has appropriate sensors to obtain the data needed for the estimation of evapotranspiration, and thereby comparing them to the results obtained by weighing. In the second plot, a rotation of crops is carried out in order to measure their ETm. Thus, it is possible to get the evapotranspiration values for each crop studied and the curves of crop coefficient (Kc) by comparison to the ETo calculated in the reference lysimeter. Finally, the third lysimeter is a monolithic with a depth of 1.70 m and is devoted to the study of grapevine irrigation (Montoro et al., 2002).

Figure 22: Lysimeter station of the ITAP in the experimental farm of "Las Tiesas" (Albacete).

The evaluation of various equations to calculate evapotranspiration (FAO-56 Penman-Monteith; FAO-24 Corrected Penman (I); FAO-24 Corrected Penman (II); Penman (1963); FAO-24 Blaney-Criddle; FAO-24 Radiation; Hargreaves (1985)) under the semiarid climatic conditions in the province of Albacete was performed. Average daily ETo values were measured with a continuous weighing lysimeter. This comparison was conducted from 215 observations carried out during the 3 years that the experimental work persisted. The conclusion of the work was as follows. In a semiarid climate, the FAO-56 Penman-Monteith method was the most precise in calculating average daily ETo, when comparing it to lysimeter

Controlled Deficit Irrigation test plots

Lysimeters and weather station

Other test plots measurements. The Hargreaves equation was the second most precise method, in spite of its simplicity (Lopez Urrea et al., 2006).

3.2.3 Field Irrigation Systems Evaluation

From the start of SIAR activities, 1301 irrigation system evaluations have been performed (Table 15). The methodology used for irrigation evaluation was derived from well-established references (Merriam and Keller, 1978; Merriam et al., 1980; Bralts and Kesner, 1983; Keller and Bliesner, 1990). In the case of stationary sprinkler irrigation systems, the norms ASAE S330.1 (2004), ASAE S398.1 (2004), ISO 7749/1 (1986), and ISO 7749/2 (1990) were applied. For center pivot, the ASAE S436.1 (2004) and ISO-11545 (1994) were adopted.

Table 15: Irrigation system evaluations (2000-2006)

System

Albacete

Ciudad Real

Cuenca

Guadalajara

Toledo

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