Post-irrigation degradation of land and environmental resources in the Harran plain, southeastern Turkey.

Irrigation is a key factor in plant production systems. However, excessive and inappropriate water and soil management systems can cause significant environmental problems. The GAP (the Southeastern Anatolia Project, SEAP) is a multisectoral integrated regional development project. It aims to improve the economical and social welfare of the region as best as possible. The two main objectives of the GAP project include irrigation and energy production. Irrigation was introduced to the Harran plain in 1995, and it led to significant changes in the land use patterns. The use of high-yielding crop varieties and chemical inputs (fertilizers and pesticide usage) resulted in important increases in plant production. Conversely, there was also an increase in land mismanagement. This included practices such as excessive irrigation, intensive soil tillage, insufficient carbon, and soil nutrient cycling. These mismanagement practices lead to soil degradation, which in turn causes increased salinity in soil and groundwater, sediment and nutrient transportation with runoffs, soil erosion, contamination of surfaces and subsurface water sources with nitrates and pesticides, and greenhouse gas emissions. In order to balance yield losses due to the decreasing soil quality, fertilizers and other chemicals were used extensively. This considerably contributed to the environmental problems. Additionally, increasing welfare and population propagated urbanization on arable lands, i.e., the construction of houses, factories, and other agricultural facilities. This further degraded the land and the environment. In conclusion, land irrigation led to production increases, but at the expense of degradation in the environment and soil quality. Moreover, land degradation occurred and further degraded the environment. It is extremely important to improve soil and water management in order to minimize these impacts. The forementioned problems could be solved by improving irrigation efficiencies, good soil and water management strategies, formation of modern well-managed irrigation districts, and educating farmers. Agricultural subsidy-based sanctions could enable these solutions. This study used archived data and evaluations of earlier studies to examine important agroenvironmental influences of introducing irrigation in the Harran plain.