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IRRIGATION SUSTAINABILITY IN THE LAND USE/SOIL SYSTEM IN
SOUTH ITALY: RESULTS FROM A GIS SEMPLIFIED APPROACH AND
FUTURE METHODOLOGICAL DEVELOPMENTS
Andrea Fais1, Rosario Napoli , Pasquale Nino , Paolo Bazzoffi , Nicola Laruccia
2
National Council For Research in Agriculture
Soil Study and Conservation Institute
Florence
1
2
3
National Institute of Agricultural Economics
Rome
INTRODUCTION
•Irrigated agricultural productions about 72 % of total agriculture’s GDP Southern Italy
Regions.
•The total area covered by irrigated crops is about 1.600.000 hectares (60 % of the total
water consumption).
•Water networks and irrigation utilities have a low degree of efficiency, with significant losses
of water (differences between sources water availability and water availability in irrigation
areas) from sources to field. The full utilisation of the available water means the possibility of
reducing the environmental impact of water use.
•The evaluation of water volumes needs very detailed information on land use, Crop Water
Requirements per crop, Irrigation techniques, and Water costs.
•The EU has financed, inside Reg. (CEE) n. 2081/93 – QCS 1994/99, the Operative
Programme (P.O.) “Water Resource, in Objective 1 Italian Regions”. This project was finalised
to the realisation of a geographic information system for water resources management in
agriculture (SIGRIA). INEA has collected data on irrigation infrastructure and on crop water
requirements in all the Southern Italy Regions Land Reclamation and irrigation Consortium
(Italian administrative structure for irrigation water management). The following information
are available thanks to this P.O.:
•Land use map CASI 3 (1:50.000 scale, and 4th level CORINE Land Cover nomenclature);
•Land Reclamation and irrigation Consortium irrigated areas and waterworks maps;
•Nominal crop water requirements (N CWR): the volumes value used in the irrigation
Consortia to define the water cost (tariff €/ha);
•Real crop water requirements (R CWR). The R CWR is based on the calculation of effective
water volumes, utilising a SWAP implemented application, that has been validated on 5
Consortia test sites;
•The information about irrigation techniques (Sprinkler - Drop – Flowing)
STUDY AREA
The work covers all the irrigated
areas of (EU) Objective 1 Italian
Regions (Figure 1). Data were
collected and organised at “Land
Reclamation and irrigation
Consortium” and regional (NUTS
II) level.
In South Italy
66
“Consortia”
manage an area of
8.358.165
hectares
IRRIGATED AREAS IDENTIFICATION: ADMINISTRATIVE BOUNDARIES
Land Reclamation and irrigation
Consortium are organised in two
principal
administrative
and
physical-territorial
units:
Comprensori and distretti (in the
picture). The boundaries of this
administrative
and
physicalterritorial
units
have
been
acquired throw direct inquire
beside the Land Reclamation and
irrigation Consortium
Capitanata Consortium
boundaries (Puglia Region)
IRRIGATED CROP GEOREFERENCED DATABASE – 1.LAND USE MAP
CORINE
code
Land
use code
211
211
Not irrigated arable
land
2121
Irrigated industrial
crops - spring – summer
cycle
2122
Irrigated Horticulture at
summer - autumn spring cycle
2123
Irrigated Horticulture at
spring – summer cycle
2124
Nurseries
2125
Greenhouses
213
Rice field
2211
Irrigated vineyards
2212
Not Irrigated vineyards
2221
Irrigated fruit and
berries plantation
2222
Not Irrigated fruit and
berries plantation
2231
Irrigated olives groves
2232
Not Irrigated olives
groves
231
Irrigated pastures
232
Not Irrigated pastures
212
213
Description
221
222
Different alphanumeric data (administrative and
statistics information) on crop surfaces were
integrated, using G.I.S. procedures, with CASI 3
cartographic data (land use classes/polygons),
inside administrative aggregations (municipalities,
administrative irrigated areas).
223
231
IRRIGATED CROP GEOREFERENCED DATABASE – NOMINAL CROP
WATER REQUIREMENT MAP
Crop evapotranspiration (ETc)
calculation is based on the
following FAO two step approach:
1.Reference
evapotranspiration
(Eto) computing;
2.Crop
coefficient
(Kc)
application,
that
take
into
account the differences in the
crop canopy and aerodynamic
resistance
relative
to
the
hypothetical reference crop.
ID
Polygon
1
2
CASI 3
code
2121
3
Description
%
He
crop
21211
Sugar beet
60
30
21213
Maize
40
20
21221
artichoke
43
30
21222
cauliflower
7
5
21223
salad
21
15
21224
potato
29
20
21231
tomatoes
17
15
21232
aubergine
9
8
21233
water melon
15
13
2122
ETc  ETo  K c
The final value refers to each land
use polygon taking into account the
irrigation techniques. It represents
the Nominal Water Volumes to use
per each map unit.
Data base
code
He
Polygon
50
70
2123
86
21234
melon
12
10
21235
asparagus
47
40
IRRIGATED CROP GEOREFERENCED DATABASE – IRRIGATION TECNIQUES
1. Information available on 275.617 he (circa 70% of the irrigated surface). The
main irrigation techniques are: - Sprinkler 58,9%; - Drop 27,2%; - Flowing 8,90%
2. In the actual dynamic, the abandon of flowing and the constant decrement of the
sprinkler techniques are both in favour of the drop system, especially on the
irrigated orchards. This process tends to reduce the utilised volumes per ha,
incrementing the on farm irrigation investment. But it actually seems to not
produce any results on the water costs.
3. The Nominal CWR (Ncwr) doesn’t take into account the differences between the
irrigation techniques inside a single irrigated land use.
Irrigation techniques (he)
Region
Flowing Submersion
Campania
Infiltration
Sprinkler
Drop
Total Region
66
65
5.514
7.115
362
13.122
Puglia
506
0
0
37.944
16.920
55.370
Sicilia
3.645
200
500
11.407
25.703
41.475
Sardegna
20
4.118
23
39.731
15.637
59.529
Calabria
1.993
730
0
6.902
681
10.306
Abruzzo
15.551
11
0
44.215
89
59.866
0
0
0
1.615
311
1.925
2.735
0
2.527
13.532
15.230
34.024
24.516
5.124
8.564
162.461
74.932
275.617
Molise
Basilicata
Total
IRRIGATION INFRASTRUCTURE INVESTMENTS AND WATER COSTS
Data on water costs (as well as the information related to irrigation networks, and related areas,
nominal CWR and irrigation techniques) has been collected on the 66 Consortia (Land Reclamation
and irrigation) surveys, based on the Q2 SIGRIA questionnaire. Data are up-dated till 1997.
200.000
EQUIPPED AREA (HA)
180.000
IRRIGATED AREA (HA)
160.000
140.000
120.000
100.000
80.000
60.000
40.000
20.000
0
The
efficiency
of
the
irrigation
infrastructure investments is based on the
ratio between areas equipped with irrigation
waterworks and irrigated areas (from 26 to
81 %). This significant difference is mainly
due to a structural insufficient water
availability to irrigate all the equipped area.
In second order, 20-25 % of this difference
is due to the normal rotation/crop shifts
inside a Comprensorio. In some cases the
irrigated areas is larger then the equipped
one. This is principally due to the private
underground water utilisation.
The unitary cost of the irrigation
infrastructures is used to quantify the
efficiency of the investments analyse.
Irrigation Infrastructures Investments (III) = average cost hectare/year of both public (IIIpub.:
adduction and distribution pipelines, plus waterworks nodes) and private (IIIpriv.: rolls and sprinkler
– IIIs - or micro-irrigation tools - IIIi) investments at Italian level (yearly amortization cost =
depreciation time: 30-40 years for pipelines; 12-15 for farm irrigation tools)
IIIs = IIIpub/ha + IIIpriv. s = 400 €/ha + 397 €/ha = 797 €/ha
IIIi = IIIpub/ha + IIIpriv. i = 400 €/ha + 788 €/ha = 1.188 €/ha
Water cost
•The infrastructures investments, both public and private, concern not only the yearly
irrigated area, but all the area equipped with pipelines, and consequently the on-farm field
water distribution equipment.
•It’s pretty clear that with the micro irrigation cost the farmer pays ad indirect additional
water cost, without any tangible direct benefits (in most cases, it doesn’t correspond to a
reduction of the tariff per hectare). Benefits that are instead completely for rural and
urban communities, and environment, having this irrigation technique direct effects on
water use savings.
Unitary Cost €/mc per Consortium
€_mc
0,350
0,300
0,250
0,200
€_mc
0,150
0,100
0,050
0,000
1
6 11 16 21 26 31 36 41 46 51 56 61 66 71 76
Consorzi
SOILS DATABSE AND IRRIGATION SOIL SUITABILITY MAP - 1
Drop soil suitability
Sprinkler soil suitability
The National Soil Database (from
the ISSDS/CRA database) is the
basis adopted to the irrigation
suitability evaluation. The United
States Bureau of Reclamation
methodology, modified by the
ISSDS during the project POM
INEA in the southern regions
(POM
IRRIGAZIONE,
19982002), has been adopted for the
evaluation procedure.
The soil map units layer is
comprehensive of:
1.Soil Cartographic Unit Code,
linked to a Soil Typological Unit in
the SIGRIA soil database;
2.Irrigation
suitability
class
codes, for the three major types
of irrigation techniques (Drop,
Sprinkler
and
Flowing/Submersion)
3.Major limitation suffix, (e.g.: PE
= slope, T = texture, D = drainage,
etc.);
4.Slope code class and related
range of values.
SOILS DATABASE AND IRRIGATION SOIL SUITABILITY MAP - 2
Sprinkler soil suitability in NW Sardinia Island
Not Suitable (N) Mod. Suitable (S2)
Suitable (S1)
Several soil features and qualities taken into account
to evaluate the irrigation suitability (surface and
internal soil).
•A matching table defines the type of limitation on
the basis of the maximum limitation criteria (the
strongest limitation determines the suitability class).
•For the slope classes, adopted the main irrigation
techniques (Drop, sprinkler and flowing) thresholds.
LAND SUSTAINABILITY TO IRRIGATION PRACTICES AND
EVALUATION OF REAL CROP WATER REQUIREMENTS
Starting from the FAO Land productivity index concept, the relationship between
the productivity index and water volumes has been estimated, based on the
assumption that the overall agronomic efficiency of water use (Fag ) doesn’t change
in the time.
•For each map unit with same soil, land use, and irrigation technique, the soil
suitability reduction factors has been directly related to the nominal normalized
water needs in the calculation of the real crop water requirement (Rcwr)
•Applying the reduction factor to the optimal CWR, the lesser suitable is the soil
the higher is the CWR value, we proposed the
•Irrigation economical and technical Efficiency Index: Ieff = Rcwr/Nwcr
•The Ieff represents the ratio between this two values The range may be variable
from 1, that is the optimal situation, to 2.5, for the not suitable soils.
Soil suitability class for specified S1 –
irrigation techniques
suitable
S2 – moderately
suitable
S3 – marginally
suitable
N – not
suitable
IEff values
1.25
1.67
2.60
1.0
Values of Ieff for the Land Units of Italy Southern Regions
RESULTS - 1
The irrigation suitability of the soil of
the South Italian Land Reclamation
Consortia irrigated areas defined with
the integration of related GIS layers.
•The Ieff index, defining the efficiency
of
irrigation
water
use
per
crop/soil/irrigation technique, allows to
calculate the extra amount of water/ha
due to an inefficient water use in not
suitable landscapes (Δ CWR mc/ha).
•Value applied on the whole irrigated
surface inside the Consortia equipped
area to have the total extra water (Δ mc
CWR) per Consortium and Region.
RESULTS - 2
•The data of the total Δ CWR in Southern Italian Region (425.228.118 mc)
represents about the 34 % of the total CWR, more or less the same quota
of the unitary value (1039,6 mc/ha).
The Δ CWR is actually wastewater or waste money (about 22 M€, based on
an average unitary irrigation water cost of 0,052/m3), but, with
appropriate rural and agricultural policies it should be considered as
saveable water for irrigated area expansion, or for other uses.
•Particularly attention has to be paid on the opportunity of expanding the
irrigated areas already equipped with irrigation waterworks, but that are
actually non irrigated for lack of water. Presently the ratio between areas
equipped with irrigation waterworks and irrigated areas is very low in
several Consortia (in table 10: Pipeline use % is about 50 % in the whole
area).
•Considering the total Δ CWR as volumes utilisable to increase the
irrigated area (G column), the total irrigated surface could rise to 553.228
hectares, with an average relative increase of 17, 6 %, and the yearly
infrastructure investment could decrease to 1.181 €/year/ha.
CONCLUSIONS
The present work tries to give the baseline information to
evaluate the efficiency in irrigation water use.
The IEff index allows to determine the additional water
wasted in an irrigation area, on the basis of the irrigation
suitability of the land use/soil/irrigation technique system.
After a first analysis of the wastewater and infrastructures
investment costs, two main considerations:
1. Farmers pay a unitary water cost that is generally far away from the
real cost; this also considering that infrastructural investments are
completely founded by the public, and are not included in water costs;
2. The low irrigation water cost compensates farm irrigation
waterworks yearly costs, particularly significant for the drop
systems;
3. The low water cost contributes to an inefficient agricultural water
use; the perfect evaluation of the real/optimal crop water
requirement will allow the farmer to pay water at least on the basis
of the real volumes of irrigation, or to reduce the unitary water
volumes.