Information Technology Reference
In-Depth Information
is maintained. Horticultural crops also initially rise to a similar level in the model and
empirically. However, empirically only melons play a role while in the model the
main share is garlic. The observed difference could be explained through small errors
in data which artificially favor garlic over melons, as discussed below. A more
significant shortcoming of the model is its inability to reproduce the empirical drop in
the area of horticulture after 1990. Irrigated vineyards rise to an approximately similar
level in the model and in empirical data but an intermediate drop (in official data) of
irrigated vineyards around 1990 is not captured by the model. The total irrigated area
and the water extractions resemble the development in areas of irrigated crops
discussed above regarding COP and horticultural crops and also the shortcomings of
the model to capture certain aspects of empirical data. The model captures the
developments of irrigated area and water extractions before 1985 but does not
reproduce a drop around 1985-1990 and a subsequent re-rise but simulation results
instead show a slight decline. The area subscribed to the voluntary AEP may be an
explanation for some of the observed differences (cf. [10] for discussion of this issue).
Irrigated crops - combined farm types
50
45
40
35
Paprica
Vineyards
Garlic
Melons
Traditional cereals
High yield cereals
Sugarbeet
30
25
20
15
10
5
0
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
year
160
900
800
140
700
120
600
100
500
80
400
60
300
40
200
100
20
0
0
1960
1970
1980
1990
2000
2010
1960
1970
1980
1990
2000
2010
year
year
Fig. 3.
The above figure shows irrigated crops. The small figures show the total irrigated area
(left) and water extractions (right), including some parameter variations. (Source: adapted from
[10])
