Drought Phenomenon and Soil Salinity

Drought phenomenon and soil salinity are known as the natural disasters affecting the human being life and natural ecosystems. In this book, the frequency and mode of drought in the previous decades and also a survey for forthcoming years is addressed by using some indices in different climatological environments of Iran. Informing and promotion of people knowledge about this issue should be a center of attention. Drought has increased recently, while better application of management strategies would have a significant effect on preventing this trend. Also, soil salinity as a degradation issue is one of the most destructive phenomena occurring in the soils of arid and semi-arid areas. Generally, in these regions the potential of evaporation is much more than the precipitation, which results in the salinity of soil leading to the reduction of fertility. Approximately, 20% of lands are affected by salinization. Forecasting studies indicates that soil salinity may be increased for the next years. Finally, to combat this threat, some approaches were presented for the reduction of soil salinity.