Most of the non-irrigated areas in the southeast of the Harran Plain are irrigated by groundwater. The aim of this study is to determine the importance of 13 underground irrigation water sources operating in the agricultural areas of Ohali village in southeast of Harran Plain in Sanliurfa province in terms of some quality characteristics and irrigation. In this context, the waters belonging to 13 underground wells were analysed and examined in terms of irrigation water quality. According to the results of the analysis, the electrical conductivity of water samples was measured between 1127-4090 µS/cm. The SAR value of irrigation water was found to be between 1.05-3.41 and the %Na value was between 16.2% - 31.8%. In the evaluation made according to four different classification systems, in general, waters 6, 7, 8 and 9 were determined as the worst quality in all classification systems. These waters are described “unsuitable” irrigation water. Considering that the plants which have high water consumption such as cotton and corn are cultivated in the region, it is foreseen that if the necessary precautions are not taken, the salinity in the soil will increase and yield losses will be high. It is imperative that these areas, which cannot be irrigated within the scope of GAP irrigation project, be irrigated with clean water as soon as possible. However, an appropriate drainage system must be installed in the area.

“Partido” is a tobacco growing area which extends for some 3000 hectares among the municipalities of San Antonio de los Baños, Güira de Melena and Alquízar in the Cuban province of Artemisa. Predominant soils are Red Ferralitic (Rhodic Ferralsol according to the World Reference Base), with a strong tendency to alkalinization which has a negative impact on the quality of their agricultural use. The aim of this research was to quantify the geographical extension of the degradation process, to determine how deep it happens along the soil profile and to establish its possible relationship with the quality and quantity of water applied to tobacco fields. The chemical, physical and mineralogical analyses of two test pits carried out in the area were compared: one profile without agricultural use with one characteristic soil profile under continuous production. After being subjected to the same irrigation regime in laboratory conditions, it was concluded that degradation affects to 89.56% of the area of tobacco soils evaluated. This phenomenon occurs very deeply along the soil profile and happens downwards, causing the accumulation of calcium and the loss of sodium and potassium in the superficial horizon, what is shown in pH rises. Such processes, associated to irrigation water and to insufficient rainfall regime which are traditional in the territory, have led to changes in the mineralogical composition of these tobacco soils appearance of minerals such as gibbsite which was absent in uncultivated Red Ferralitic soils, which involve the modification of soil classification at gender level.