Characteristics of cropland: Crete and Messara Valley

Authors: Constantinos Kosmas, Katerina Kounalaki, Mina Karamesouti

Editor's note 30 Apr 2012: Text source D111-2.2. The first section "Greece climate, soils and agriculture" will be deleted. It is expected that this same information will be contained in D131.

Greece climate, soils agriculture

Greece is located between the latitudes 34° 48' 02'', 41° 44' 58'' Northern latitudes and 19° 22' 41'', 29° 38' 27'' Eastern longitudes. It includes over 2000 islands, 75 of which are inhabited, and covers a total area of 131,191 km². The maximum length from north (Rodopi) to south (Crete) is 727 km, while the maximum width is 570 km. The majority of the Greek land area is mountainous with steep slopes. Approximately 49 percent of the surface area has slopes greater than 10 percent, and only 36 percent comprises lowlands with slope less than 5 percent. Areas at elevation greater than 800m occupy 28.6 percent of the country. The highest elevation is Mount Olympus at 2,917 m.

Crete is the largest island in Greece and is located in the south of the country (Figure 1).  The island of Crete covers an area of 8313.3 km².  The length is 250 km while the widest part of the island is 56 km. The narrowest part of the island is 12 km, and is located in the eastern part of the island close to Ierapetra city. Crete is a rugged, mountainous island with high variation in altitude within relatively short distances. Due to its predominantly steep terrain and adverse climatic and bio-climatic conditions, the island faces significant soil erosion problems.  In total, 79.5 percent of the surface area is comprised of slopes greater than 12 percent and only 6.9 percent of the land comprises lowlands with slope less than 6 percent. 

Figure 1. Location of the study site, Crete. Source: (Author C. Kosmas)

Mountain soils in Greece are extremely eroded due to the steepness of slopes, are shallow and poor (Leptosols, FAO classification system) (Fink et al. 1998), and useless for agricultural activity. On the uplands, the steep slopes, combined with the removal of natural vegetation (fire, cultivation, overgrazing), have caused soil erosion and the prevailing soils are characterized as Cambisols, Luvisols, and Regosols. Due to their low fertility and productivity it is questionable whether these lands should be used as cropland (Kosmas et al. 1998). The lowland soils are more productive. They can be subdivided into three main groups. The first group includes soils formed after reclaiming former lakes such as Gianitsa, Tenagi Filipon, Kopais and Karla. These are the most fertile soils, characterized by high productivity (mainly Mollisols and Fluvisols). The second group includes cultivated soils of moderate to high fertility, temporarily flooded and characterized by a shallow groundwater table (hydromorphic counterparts of Fluvisols, Cambisols, Luvisols, Vertisols, etc.). The third group includes lowland soils with low organic matter content and with moderate to poor fertility. Therefore, soil fertility is mostly determined by texture, the type of clay and soil depth. About 150,000 hectares of land in the lowlands contains amounts of soluble salts to such a degree that they need reclamation before any use. Based on soil, climate and topography characteristics, land of high potential quality represents 19 percent of the total land surface (CORINE 1990), 18 percent is of moderate quality and 57 percent of low potential quality. Much of the low quality land is used for traditional, low capital intensity farming systems which are important in maintaining the characteristic Mediterranean landscapes.

The climate of Greece belongs to the Mediterranean type, according to which most rains fall in the cold period October-March whereas the summer months July-August are almost without precipitation. The amount of rainfall ranges from 780 to 1,280 mm per year in the western part of Greece, this amount being reduced by about half in the eastern part, which ranges from 380 to 640 mm per year. As far as temperature is concerned great variation exists. Greece lies between the isotherms of 14.5°C and 19.5°C. During the cold period, temperature increases with decreasing latitude, whereas in the warm period and especially between May and August temperature increases from the coast to the mainland and particularly the plains. In winter, the lowest temperatures occur in northern Greece reaching occasionally -20°C whereas in the southern parts and Aegean islands, temperature scarcely falls below 0°C. In the summer, temperatures greater than 40oC may occur in the lowlands of the Greek mainland, contrary to the islands and coastal areas, which rarely reach 40°C due to the northern winds locally named “etesians”, and local winds. With regard to sunshine duration, certain Greek regions have some of the highest number of hours of sunshine in southern Europe. The western coast of Peloponnesus together with the Ionian coast and the Aegean islands have more than 3,000 hours of sunshine per year. The remaining coasts have about 2,500 hours and inland this figure is approximately 2,300 hours.

Agriculture plays a major role in the Greek economy. Together with forestry and fishery, its contribution to the country's economy is about 18.5 percent. Greek agriculture has rapidly modernized since the late 1950s when self-sufficiency in wheat production was attained. Since then, soil amelioration and mechanization, application of fertilizers, pest-disease control, introduction of improved varieties, and expansion of the total irrigated area have led to a dramatic increase in agricultural output (Sala et al. 1998).

The country's food situation had already substantially improved before Greece’s entrance into the European Union in 1981. After that, agricultural development focused on maximization of fodder and cash crop production which resulted in intensive arable cropping on all fertile, irrigable lands. Further mechanization and expansion of the irrigated area to 1 million hectares were realized soon after the country became a full member of the European Union (Boyatzoglou 1983).  

Greece adopted a system of farming cooperatives as early as 1915 to streamline farming efforts. These cooperatives have been supported by successive governments. After the 1980s, the cooperatives were greatly enhanced and received a large percentage of agricultural loans. Furthermore, the European Union has allocated to Greece a number of subsidies to bolster its agricultural sector, but it continues to perform poorly. To expand the market for Greek food exports, the Ministry of Agriculture established a private company (Hellagro SA) to assist Greek companies in selling their products through the internet. Private stockholders will hold the majority share in Hellagro, and financing will come from e-commerce, commission, investment opportunities and joint ventures (Boyatzoglou 1983).  

In recent decades, Greek agriculture has been characterised by an increasing diversification of fruit crops for export. Furthermore, the area of land under arable production has decreased due to high a degree of degradation, or as a result of changes in land use. As Figure 2 shows, the land available for production per head of population has changed from 0.34 in 1968 to 0.23 (ha/person) in 2008 (World Bank 2011). 

Figure 2. Change of arable land area per person with time in Greece. Source: (World Bank 2011)

 Greece had managed to achieve a fast-growing economy after the implementation of stabilization policies in recent years, at least, prior to the global financial crisis of 2008–2009. Greece has a predominately service economy which (including tourism), accounts for over 70 percent of GDP. Greece realigned its economy as part of its EU membership, which began in 1981 (Petmezas 2005).  Although agriculture accounts for 20 percent of the work force, its role in the economy is declining. In 2000 agriculture accounted for 9 percent of GDP, compared with 25 percent in the 1950s. Agriculture has been further affected by the current economic conditions of Greece and the global recession.  

Cropland in Greece

Cropland in Greece covers 3,896,344 ha or 30 percent of the Greek territory.  Arable land (including temporary crops, temporary meadows for mowing or for pasture and land temporarily fallow) is the most extensive, covering 2,221,900 ha (Greek Agricultural Statistical Service 2001). Tree crops (except vines) cover 998,213 ha; vineyards 132,083 ha, and others (vegetables) 116,348 ha. Land corresponding to fallow covers an area of 427,800 ha.

As Figure 3 shows, cropland is mainly found in the plains of Thessaly, Macedonia, Thrace, Peloponnesus, and Crete. The main arable crops are corn, wheat, barley, sugar beets, cotton, and tobacco, while the main crop trees are apples, pears, peaches, apricots, oranges, olives, and vines.  A wide range of seasonal and out of season vegetables are also cultivated, such as tomatoes, melons, watermelons, cucumbers, potatoes and strawberries. While agriculture is not a thriving economic sector, Greece is still a major EU producer of cotton and tobacco. Greek olives—many of which are turned into olive oil—are the country's most renowned export crop. Grapes, melons, tomatoes, peaches and oranges are also popular EU exports. Wine is a widely exported product and is expected to increase in terms of production.

Figure 3. Distribution of various types of cropland in Greece.  Source: (Author C. Kosmas based on CORINE 2000 data)

As shown in Figure 4 below, the total area of cropland in Greece has declined in past decades due to low land productivity and land abandonment. The area under arable crops has decreased from about 2,700,000 ha in 1961 to 2,180,000 ha in 2003. Arable crops have been replaced by tree crops such as olives and the area covered by trees has therefore increased from 510,000 ha in 1961 to 1,000,000 ha in 2003. Vineyards show a slight decrease in area over time, while the area under vegetable cultivation remains relatively stable. 

Figure 4. Change in cropland area in Greece over time. Source: (Greek Agricultural Statistical Service 2003)

Olive groves in Greece occupy an area of about 717,400 hectares with about 140 million trees cultivated by 686,000 families. Olive oil production in Greece has increased from circa 186,000 tonnes in 1971 to 330,000 tonnes in 1995 and to 451,000 tonnes today. Olive oil production in Greece represents 23 percent of total European Union production.

Olive groves in Greece are usually intensively cultivated. Soils are usually ploughed once in mid-spring and in several cases are treated once or twice a year with herbicides. Another management practice which is related to organic olive oil production is no tillage and no pesticides.  Fertilizers are usually applied once during winter or early spring. If water is available, olives are irrigated 3 to 5 times during the dry period, applying the water usually by drip irrigation. Some of the management practices applied in olive groves which have significantly improved production include:

  • Pruning for rejuvenation or fruit production at the time of harvesting which significantly affects production.
  • Fertilizer input using mainly nitrogen or phosphate fertilizers, increasing plant growth and production.
  • Weed control by mechanical cultivation or herbicides applied once per year, early in spring for conserving soil water and facilitating harvesting.
  • Complementary irrigation applied in areas with low rainfall or in years with limited rain, particularly during spring, which contributes to greater production.
  • Dacus or other pest and disease control, which is of great   importance for both yield and quality. Dacus control is applied to all olive groves by the Regional services of the Ministry of Agriculture in collaboration with local Co-operative unions.

Irrigated land in Greece today covers about 37.9 percent of the national cropland area or 1,476,714 ha. The area of irrigated land has doubled compared to the decade 1960-1970 (Figure 5).  The over-exploitation of ground water for irrigation of summer crops has had adverse consequences on soils due to intrusion of sea water and salinisation. Additionally, increasing tourism in the last 40 years has exerted a significant impact on the environment and in particular on land-use patterns and the allocation of water resources. In order to meet the high water requirements and to protect the intensively cultivated plain areas, multiple use water reservoirs (irrigation and consumption) have been constructed or are under construction in Greece. Fourteen large water dams have been constructed along the main rivers in which the water stored is mainly used for electricity production and irrigation. The total water storage capacity of these dams is 9,551 million m³. Ground water recharge is another management practice to improve ground water quality and to avoid soil salinisation. For example, on the Argolis plain, which is facing severe problems of intrusion of brackish water and soil salinisation, recharge of the aquifers is achieved by supplying good quality spring water through wells during the winter period (Sala et al. 1998).

Figure 5. Change in percentage of irrigated land over time in Greece. Source: (Greek Agricultural Statistical Service 2009)

Cropland in Crete

Cropland in Crete covers an area of 313,376.9 ha (including fallow land) or 37.7 percent of the total land area. The Prefecture of Heraklion has the greatest area of cropland (Table 1). The most extensive cropland in Heraklion is located in the Messara valley. Olive and vine plantations are the main trees, covering a large part of the lowlands and hilly areas, but also parts of the uplands. The most significant expansion of olive groves occurred during the last forty years after maquis and shrub vegetation were eliminated (Figure 6). Vine plantations declined significantly due to destruction by phylloxera. New plantations, with increased resistance to phylloxera, have appeared in the area in the last decade. Cereals drastically declined in Crete after 1950 and were replaced mainly by olive trees or vines.

Table 1: Area of cropland and fallow land in Crete by category and geographic region, 2006

Geographic region Cropland area (in ha)
Total (including fallow land) Arable land Garden, raisins Vines and compact plantations Crop trees Fallow land
Crete 313376.9 30017.2
8549.5 25522.8 190082.2
59205.2
Heraklion 145140.8 15198.5
3749.2 19418.8 83770.9 23002.3
Lassithi 55421.6
 4911.5 2049.2  2330.3 30628.3 15502.3
Rethimno 51848.5 
6204.2 1045.1 1856.1
28605.4  14137.7
Chania 60966.0 
3703.0
1706.0 1917.6 47077.6 6561.8

Source: Greek Agricultural Statistical Service 2006.

Figure 6. Change in cropland area (ha x 10³) in Crete over time. Source: (Greek Agricultural Statistical Service 2006)

 Olive groves are found across Crete, covering 193,724 ha or 23.5 percent of the total area.  The island of Crete, and especially the Messara valley, faces significant problems of water resource over-exploitation due to the expansion of irrigated cropland, such as olive groves. Although the Valley receives on average about 600mm of rainfall per year it is estimated that about 65 percent is lost to evapotranspiration, 10 percent as runoff to sea and only 25 percent goes to recharging the groundwater (Vardavas et al. 1996). An extensive network of pumping stations has been installed since 1984 in which rain-fed olive groves have been converted to irrigated olives. The consequences are an increase in crop production accompanied by a dramatic drop of up to 20m in the groundwater level in some places, and intrusion of brackish water in the aquifers.

2014-11-28 10:50:14