**1. Introductıon**

Land degradation comprises human-induced processes that affect land resources and environmental sustainability. Land degradation is recognized as one of the most serious ecological and economical problems globally. Soil erosion, soil compaction, deterioration in soil structure, nutrient depletion, acidification, and salinization have been defined as major soil degradation processes [1]. The human activities such as fires, floods, soil loss (SL), and

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

yield reduction may affect land degradation directly or indirectly. In the twenty-first century, land degradation is considered an important factor affecting food security. The world's agricultural land that is seriously degraded is estimated to have reached up to 40% [2].

Land degradation in Turkey has been mainly in the form of soil erosion, agricultural mismanagement, deforestation, and overgrazing, and is a result of human activities for the last century. The most prominent result of soil degradation in Turkey has been soil erosion, which develops due to the region's climate, topography, soil, and land-use problems. In Turkey, 59% of rangelands, 54% of forest lands, and 71% of agricultural lands are under active erosion threat [3]. Furthermore, an area of 4.2 million ha has lost its productivity partly or completely due to salinity problems [4]. Topographic and climate conditions have made it necessary to combat soil erosion. In Turkey, 24.1 million livestock graze on pastures, but the pastures can no longer provide sufficient roughage for the livestock to feed, and the existing land cover on pasture areas are used intensively. Overgrazing, especially noticeable in Turkey's Mediterranean, Aegean, Southeastern, and Central Anatolia regions, damages vegetation, increases runoff, and promotes erosion. The surface coverage of pasture areas ranges from 15 and 30%. Severe water and wind erosion are visible in those areas. To avoid soil erosion, surface coverage should be increased in the pasture areas where misuse is taking place—an area of 21.7 million ha. The amount of grazing animals and their grazing time must be brought under control [5]. Land use has changed in significant ways over the last 100 years in Turkey due to agricultural expansion. For example, while pasture areas made up about 56.8% (44.2 million ha) of land use in 1940, today they are only 18.6% (14.6 million ha). Most of changes to land use occurred on pasture land that was converted to agricultural purposes [3].

The main objective of this study is to evaluate soil degradation regarding wheat yield (WY) as affected by deteriorated soil properties in the Çelikli basin, located in North Central Anatolia of Turkey.
