In this work several performance
indicators such as the Annual Relative Irrigation Supply
(ARIS) and the Irrigation Water Productivity (IWP),
have been considered to evaluate the changes in the
cotton irrigation management due to the decoupling of
the European Union Subsidies. For this purpose, a
modern irrigation scheme, the Genil–Cabra Irrigation
Scheme (GCIS) located in Southern Spain, has been
selected. The total irrigated area is 6,900 ha with wheat,
olive and cotton as the main crops. The irrigation season
2004/05 was the period when the crop pattern and water
management trend changed dramatically. From this
year to the present the area cultivated with crops with
high water requirements like cotton, sugar beet and
maize has been reduced almost by half, while the area
with low irrigation requirement crops (winter cereals,
sunflower or olive) has increased of 37%. After the
decoupling of the EU cotton subsidies in 2006, the cotton
agricultural practices have changed toward a less
intensive production system, including both, lower water
application (ARIS for cotton decreased from values
higher than 0.8 to 0.5 in the irrigation season 2006/07)
and less agrochemical usage. In terms of sustainability,
the reform has increased the cotton irrigation efficiency
(IWP for cotton increased from around 0.7 €/m3 to 1.0
€/m3 in the irrigation season 2006/07) and has reduced
its environmental impact
