Case Study Site 5: Crete, Greece
Responsible partner: 17 - AUA
1. Geographical description
The study site of Crete is bordered to the north by the Sea of Crete and to the south by the Libyan Sea (Figure 6) and covers an area of 8336 km2. Cultivated land covers 42.0% of the island, while dry land is used mainly as pasture as the next most important land use covering 39.3% of the area. The island is characterized by sloping land with slopes >12% in 79.5% of the area, while only 6.9% is comprised of lowlands with slope <6%. The coordinates of the study site (coordination system: UTM-WGS – Zone 33 North) are: left: 452134.31250, right: 713874.3750, top: 3949935.0000, and bottom: 3864285.0000.
Figure 6. Location of Crete study site.
2. Main farming systems and typical agricultural management activities in the study area
Climatic and soil characteristics accompanied by EU policies on subsidizing crops in the last two decades, have greatly favoured the extensive expansion of olive and vine plantations in the area which provides farmers with higher incomes. Orange plantations and vegetables grown in greenhouses have been mainly expanded in the lowland areas of the island. High amounts of fertilizers have been applied up until the last decade. However, farmers have realized the negative impacts on the environment and the increasing cost of crop production and thus the amount of applied fertilizers have steadily decreased. Drip irrigation has been expanded in the cropland areas to ensure increasing crop production. However, the over-exploitation of the aquifers has resulted in deterioration of water quality (high soluble salt content), thereby affecting soil salinization. The lack of good quality water has stimulated the construction of small reservoirs for increasing water availability for irrigation.
The intensification of agriculture resulted in accelerated rates of soil erosion in the hilly areas of the island. Furthermore, water pollution of the aquifers has become an important issue due to over-fertilization of the land and overuse of plant protection chemical products. Land desertification due to salinization in the lowlands and due to soil erosion in the sloping areas has become an important issue. Organic farming and integrated land management practices have been established in some areas for the protection of soil quality and ecosystem functions.
3. Characteristic soils and soil quality monitoring practice
The soils of Crete reveal various stages of soil development. Cambisols are widely present on the island covering 43% of the total area. Leptosols are located mainly in mountainous areas covering 50.9%. Fluvisols and Luvisols are mainly located in the river floodplain areas and cover a small percentage. Soils have been formed in a variety of parent materials such as limestone, shale, marl, conglomerates, flysch, and alluvial deposits. The dominant parent material is limestone covering 48.0% of the total area, followed by marl at 19.1%. Soil texture is mainly characterized as moderately fine, and evident in 78.0% of the total area. The next important class is medium covering 13.6% of the area. Fine textured soils cover only 6.9% of the area. As Figure 7 shows, very shallow (depth 0-15 cm) and shallow soils (15-30 cm) are widely distributed throughout the island of Crete, covering 16.4% and 34.6% of the total area, respectively. Moderately shallow (30-60 cm) and moderately deep (60-100 cm) soils cover 14.1% of the area at 25.8% and 18.1%, respectively. Deep and very deep soils covers 8.4% of the island, and are characterized as the most productive soils. The high amount of rock fragment (RF) in the soils is an indicator of high degradation of the soils in the past. Soils with 40-60% RF in the soil surface covers 49% of the total area. The next important class of RF is 15-40% covering 29.3% of the total area. Concerning drainage, soils are characterized as very well or well drained (98%).
Figure 7. Spatial distribution of soil depth classes in the island of Crete (source: LEDDRA project, http://leddra.aegean.gr/).
The existing practices can be characterized as positive or negative in terms of soil quality monitoring. The following practices are mainly evident in Crete: (a) intensive cultivation of land accompanied by disk harrowing and application of fertilizers and pesticides (negative), (b) integrated land management in olive groves by applying measures for environmental protection (positive), (c) drilling wells and expansion of irrigation in olive groves and vineyards (positive/negative), and (d) overgrazing in pasture land (negative). Intensive cultivation which is widely evident in the area has mainly negative impacts causing problems of soil erosion, ground water pollution, and deterioration of soil physical and chemical properties (decrease in soil organic matter content, soil aggregate stability deterioration).
4. Ongoing research and innovation actions on soil improvement and monitoring
The following research or actions on soil improvement and monitoring are or were going on in the island of Crete:
- Research on assessment of land management practices on soil erosion and land desertification (Agricultural University of Athens).
- Integrated land management practice in olive groves by allocating extra subsidies.
- Project on development of agricultural soil database and assessment of land suitability for crop production and vulnerability to land degradation (Greek Ministry of Rural Development and Food).
- Research on Desertification Mitigation and Remediation of Land: a global approach for local solutions – DESIRE (www.desire-project.eu).
- Research on Land Ecosystem Degradation and Desertification: assessing the fit of responses- LEDDRA EU project (http://leddra.aegean.gr/).
5. Stakeholders to be included in the research
- EKO DIMITRA- Institute of Olives and Sub-tropical Plants of Chania
- Municipality of Hersonissos, Crete-Greece
- Municipality of Aliartos, Viotia-Greece