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Desertification Indicator System for Mediterranean Europe


1. Definition

Name IRRIGATED AREA
Brief definition Land area under irrigation as a percentage of total arable land area
Unit of measure %

2. Position within the logical framework DPSIR

Type of Indicator Driving Force

3. Target and political pertinence

Objective The purpose is to show the degree of importance of irrigation within the country's agricultural sector, from the point of view of water and land resource utilization
Importance with respect to desertification This indicator shows to what extent arable land and water resources are already used in an intensive manner. It can indicate level of conversion of land to high input agriculture. Availability of irrigation water is linked to other intensification processes with potentially negative effects on sustainability, such as monoculture, selection of high yielding varieties to the detriment of genetic diversity, runoff and soil erosion, compaction, and salinization that lead to accelerated desertification process. Sustainability assessment of changes in the indicator is linked to water availability and soil suitability for irrigation
International Conventions and agreements The UNCCD emphasizes the development of sustainable irrigation programmes for both crops and livestock as a measure to prepare for and mitigate the effects of drought.
Secondary objectives of the indicator Extensive standing water area is linked to incidence of salinization. It also relates to conflicts in the use of water resources.

4. Methodological description and basic definitions

Definitions and basic concepts

Arable land is officially defined as "land under temporary crops, temporary meadows for mowing or pasture, land under market and kitchen gardens, and land temporarily fallow." That definition tends to equate arable land with cultivated land. The Food and Agricultural Organization's (FAO) definition of cultivated land is that under temporary (annual) crops, but some countries (outside the EU) may include perennial crops in cultivated land. Therefore, complications may arise from cross-country comparisons.

The way multiple cropping and intercropping are accounted for is not standardized and not always clear. Irrigation potential is determined on assumptions that vary from country to country. It should be based on annual/seasonal water and land resource availability (depending on topography, infiltration). As land and water resources do not always coincide, technological options (i.e. basin transfers, storage) should be judged by economic and environmental considerations. Except in a few cases, no consideration is given to the possible double counting of shared water resources. Mangrove, wetland and flood plains (resources with high environmental value) are usually, but not systematically, included in the irrigation potential. The concept of "water managed areas" includes "irrigated areas" (i.e. equipped with hydraulic structures) as well as cultivated wetland and valley bottoms without irrigation equipment.

Benchmarks Indication of the values/ranges of value Trend
Methods of measurement Irrigated area (area equipped with hydraulic structures) divided by arable land.
Limits of the indicator There are conceptual and methodological difficulties of interpretation. Some national data use a narrow definition while other data may be broadly defined. Some countries report areas with irrigation facilities, while others use areas provided with water, so the differences between irrigable areas and irrigated areas (areas where water is effectively used) is not clear. The indicator value does not capture the quality or conditions of both land and water resources. Knowledge of other factors such as crops grown, agro-ecological zone type, and distribution of farm size would be relevant to its interpretation. Other aspects of irrigation, including equity, efficiency, and importance to the overall national agricultural production are not reflected in the indicator. The indicator does not provide a measure of lands with irrigation potential.
Linkages with other indicators Water leakage; Irrigation potential realised; Area affected by salinity and water logging; Annual withdrawals of water; Groundwater reserves; Land use evolution.

5. Evaluation of data needs and availability

Data required to calculate the indicator Data on irrigated land and arable land.
Data sources Regional and National Agencies involved in the managing of water resources (i.e. Authority of Basin in Italy). Data on Arable land is available from Agricultural Census
Availability of data from national and international sources Recent data are available at the country level in FAO's AQUASTAT (1994/1995) which is directly based on official national data. Data are also available from national sources in some countries only. The data are estimated by countries at various periods and are then interpolated. Data from 1970s are available as part of country statistics in WAICENT

6. Institutions that have participated in developing the indicator

Main institutions responsible University of Basilicata
Other contributing organizations Universities of Lisbon, Murcia, Athens

7. Additional information

Bibliography Eurostat. 1997. Agriculture Statistical Yearbook 1997. Luxembourg.
Other references The lead agency is the Food and Agriculture Organization (FAO). The contact point is the Assistant Director-General, Sustainability Department, FAO; fax no. (39 6) 5225 3152
Contacts Name and address Prof. Giovanni Quaranta
Dipartimento Tecnico-Economico per la Gestione del Territorio Agricolo-Forestale
Università della Basilicata
Via Macchia Romana
85100 Potenza
Italia
quaranta@unibas.it