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Erhan Akça 1, Selim Kapur 1, Memduh Serin 2, Bahri Çevik 3, Hari Eswaran 4 1 University of Çukurova, Department of Archaeometry, Adana, Turkey 2 İstanbul University, Department of Biology, İstanbul, Turkey 3 University of Çukurova, Department of Engineering, Adana, Turkey 4 USDA Natural Resources Conservation Service, Washington DC, USA ABSTRACT The Karapinar area occupies a desert fringe position in the Great Konya Basin of Central Anatolia. Grazing has been a way of life for centuries and the population gathered wood from the shrubs for fuel. The village has served crusades and hoards moving east west over Anatolia. In the middle of this century, due to rapid increases in animal population, the scanty vegetation was denuded and the land further exposed to the vagaries of climate. By the fifties, wind erosion had noticeably increased and active dune formation could be observed. The General Directorate of Rural Services responded by establishing an Erosion Control Camp (with the third author assigned as the soil conservationist). A soil survey was conducted in the early sixties and other management studies were initiated. The initial successes were encouraging and in the seventies an area of 14,000 ha was fenced off and the land set-aside as a wind erosion rehabilitation area. Today, about 30 years later, the site is known as "Köy Hizmetleri Toprak Tali İstasyonu or Soil Conservation Sub-station of the General Directorate of Rural Services" and has become a teaching and demonstration center for managing land prone to wind erosion. It is also fondly referred to as a monument to visionary thinking and good land management science. The purpose of the present study is to observe the major changes in the quality of the land resource. Aerial photographs, other documentation, the soil map of 1965, and historic climatic data were used to evaluate the conditions prior to application of mitigation technology. A new soil survey was commenced, samples were taken close to the points of the original sampling, recent aerial photographs were interpreted, and discussions were held with farmers and villagers in the area. The changes in the three decades are an example of the resilience of the ecosystem. The experiment is also an illustration of how processes of desertification can be thwarted through a managed ecosystem that ensures a balanced mixture of agricultural land use of ecosystem integrity. Land allocation for biodiversity, stabilization of moving sands, protection of the more fragile lands, and technically sound management of better lands, have cumulatively resulted in a truly sustainable land system in this desert margin. The study is quantifying the changes so that the ecosystem management principles can be duplicated elsewhere. INTRODUCTION The Anatolian Plateau is a vast undulating landform occupying the interior of Turkey. In the Southern part it is bounded by the Taurus mountain range as a result of which there is no drainage outlet. The Great Konya Basin, a closed basin with an area of about one million hectares, occupies the central part of the plateau and the study area, Karapinar Plain, is located on the southeastern part of the Konya Basin. Historically and traditionally, the region is used for grazing and in the last few decades, irrigation facilities have been introduced for cultivation of wheat and other cereal crops. Major constraints for land use are wind and water erosion and salinization. Being a closed basin, irrigation results in secondary salinization and though measures have been taken to reduce the intensity of this process, it remains a continuing struggle. The soils are generally sandy and silty and with the land being bare for extended periods during summer, it is extremely susceptible to wind erosion. The problem is compounded by low-input agriculture. Modern land management technology, such as minimum or zero tillage has yet to be introduced. During the dry summer months, average wind velocity is 18 to 25 m/sec, with a wind direction of north-northeast. Enterprising farmers have constructed windbreaks of poplar and other trees. Wind erosion and shifting sands reduce the quality of the land and an experimental station was established at Karapinar in 1962 to address the issue. Over-grazing by the increasing sheep flocks has denuded and prevented reestablishment of vegetation. Subsequent to a soil survey of the area (Groneman, 1968), a 14,000 ha of land was fenced-off. A hydro-geological survey provided information on ground-water resources. To prevent local farmers from gathering wood or graze their herds, a barbed wire fence was installed. Thirty-two wells, 60 to 70 m depth were dug to provide water. In designing the area, four sections were established to implement different kinds of conservation practices. Small tracts of land were set aside to serve as comparative study areas or control plots. Over the years, rehabilitation was commenced on the remaining areas. A first priority was stabilizing the dunes. These were vegetated using innovative technique to supply water for the young shrubs. Based on the soil map, the remaining undulating lakebed soils were selected for reforestation or to be used for irrigated agriculture. In the next decade, irrigating conduits were constructed and irrigation systems put in place. Early station records show that a prime challenge was to enhance the organic matter content of the soils while simultaneously ensuring that salinity levels were not being adversely affected. The purpose of the study was to evaluate the changes that have taken place in the last 30 years. The major focus is on soil properties and conditions because of the availability of the 1968 soil map and documentation. Discussions with other scientists who have worked in the area during the last two decades have provided additional information on productivity, changes in faunal activity, biodiversity, and the general ambiance of the area. These are summarized to emphasize the improvement in land quality and the related consequences. METHODS The soil map of Groneman (1968) was digitized and all other maps produced for the study were developed at the same scale and used as overlays. Aerial photographs taken at periods prior to the beginning of the station and recent ones (1989) were also interpreted and digitized to serve as overlays. The 15 sites sampled for characterization in the original study were located and re-sampled in 1998. Satellite samples were taken to monitor the depth of the sand, particularly at points close to dunes. Studies of other disciplines, particularly those related to vegetation, biodiversity, and productivity, were used to infer on aspects of land quality and resilience of the ecosystem. Physiographic Setting : The study area (Fig. 1) comprises a paleo-lake, which is one of the many lakes that formed in the Great Konya Basin of Central Anatolia, and adjoining beach deposits. On the west is an "old sand plain" of pre-Wurm age, loacted at an elevation of 1035 to 1050 m above sea level and about 35 m above the paleo-lake. The north of the paleolake is the basaltic lava flows of the Ketir-Mekeler system and which forms an obstacle for the northern transgression of the mobile sands. The dune field of Karapinar was mobile until the start of the rehabilitation program in 1960. The field is made of sand barchans grouped in-moving chain. They reach 240 m in length, 150 m in width, and about 40 m in height with a windward slope of about 5-20% and leeward slopes of about 30-60% (Erinc, 1962). The sand contains large amounts of shell fragments pointing to its lacustrine origin and some volcanoclastic fragments as inclusions. Roberts (1983) estimates the deposits to date to 13-11,000 BP. Geologists working in the area have recognized at least two generations of younger dunes. The older of the two are relatively stabilized by vegetation and it is the younger, present on the dried lake-floor bed that is mobile.  Mean annual rainfall of the area is about 277 mm with an evapotranspiration of about 780 mm. The rain commences about January and ends in mid-June. Winter soil temperature only exceeds 5oC in mid-March and so the available rainfall during the growing season is only about 80 mm. The soil moisture regime is weak aridic and the soil temperature regime is mesic (Soil Survey Staff, 1998). The period during which the land is bare and thus vulnerable to wind erosion is about 200 days. DISCUSSION AND CONCLUSION With intensified land use in the Great Konya Basin, soils are becoming degraded through erosion and salinity build up. A survey conducted in 1976 (Cangir, 1998) showed small area subject to degradational processes but this has increased in a repeat study in 1996 (Table 1). The best quality lands are most severely affected. About 1% of the Basin is now currently affected and most of the damage is irreversible.  The Karapinar Conservation area has now validated technology to contain wind erosion and minimize salinity build-up. One of the challenges is to transfer some of these technologies to the Konya Basin farmers. There are still other continuing constraints to sustainable land use in Karapinar, which requires yet other technologies. This deals largely with the areas under irrigation. Though the period during which the land is bare has been significantly reduced through cropping, crop residue removal and burning of straw both reduce carbon sequestration and make the land surface vulnerable to wind erosion. Minimum tillage and some straw incorporation into the soil needs to be dome to build-up the organic matter status of the soils. Biodiversity enhancement has yet to be adequately addressed. Experience is lacking and knowledge must be transferred from other parts of the world. Establishment of shallow farm ponds at strategic places would provide a water source to attract birds and other fauna. As human presence is very low at the site, it becomes an attractive recluse for wildlife. REFERENCES Cangir, C., Kapur, S., Boyraz, D. and Akça, E., 1998. The Problems of Agricultural Soils and the Strategies of Optimum Land Use in Turkey. M. Sefik Yesilsoy International Symp. on Arid Region Soils, 21-24 September 1998, Izmir, Turkey pp 464-472. Erinc, S. 1962. On the relief features of blown sand at the Karapinar surroundings in the Interior Anatolia. Review Geographical Institute, Univ. Istanbul. 8:113-130. Groneman, A.F. 1968. The soils of the wind erosion control camp area, Karapinar, Turkey. Ph D. Thesis, Agric Univ. Wageningen, Netherlands, 160 pp. Roberts, N. 1983. Age, paleo-environmental and climatic significance of Late Pleistocene Konya Lake, Turkey. Quaternary Research. 19:154-171. |