Özet:

Irrigation is the most important practice that guarantees high agricultural production in arid and semi-arid regions. Notwithstanding, various problems may arise in irrigation practices. These problems result from the imbalance among soil, plant and water relations. The fact that the farmers do not know how much water, when and which irrigation method to apply causes inappropriate irrigation practices. In addition, the use of primitive irrigation methods of low efficiency by the farmers is also very common. This does not only hinder sustainable irrigated farming but also leads to salinity and alkalinity problems, thus resulting in the loss of fertile soils. Monitoring and evaluation of groundwater (GW) depths as well as salinity of GW and soil to ensure the sustainability of irrigated agriculture and water management is a necessity in agriculture. Because GW depth and salinity, and soil salinity are among the most important factors that negatively affect production in agricultural areas. Poor irrigation water management, low irrigation efficiency, the inadequacy of in-field drainage systems etc. are the main reasons for drainage and salinity problems in irrigation areas. This study aimed at monitoring changes in soil salinity by conducting the salt balance work in a large irrigation scheme (9 495 ha), located in the Lower Seyhan Plain, in southern Turkey. Field studies were carried out in the hydrological year 2008. Research results showed that the salt balance equation resulted in a closure error of ΔS= -2.84 Mg ha-1. Results indicated that the amounts of salts exported by drainage flows were greater than the salts imported by precipitation and irrigation water. In turn, not only precipitation in the winter but also irrigation applications in the summer season are effective in leaching salts out of the root zone. This is due to poor irrigation efficiency and high drainage fraction in the District.

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