Degradation of soils as a result of long-term human-induced transformation of the environment in Iran: an overview

Human-induced soil degradation is a serious and complex environmental challenge in Iran. For a long time, human activities, namely the overuse of land, have been influencing the natural processes on and in soils; therefore, various types of soil degradation can be observed in many parts of the country. The understanding and the consideration of direct and indirect effects of human activities on soils are indispensable for the prediction of the human impact on soil degradation processes. There are many important direct and indirect anthropogenic causes that play an effective role in soil degradation; they have a significant relationship with the natural resource management in Iran. Population dynamics, deforestation, and overgrazing as main causes and salinization, alkalinization, water-logging, soil erosion, and desertification as main effects of human-induced soil degradation are highlighted in this overview. Population in urban areas of Iran strongly increased from 1936 (21% of total population) to 2010 (72% of total population). Nearly 5 million hectares of forest were converted to farmland and urban areas from the 1950s to 2008. The area of Iran's cultivated land was enhanced by more than four times. Livestock population is around three times higher today than the capacity of the rangelands. Regarding this overview the study of land management, soil degradation, and soil conservation in Iran needs an integrative approach. Therefore, a transdisciplinary model to assess environmental, economical and social factors (and thus sustainability), namely in arid and semi-arid areas, is offered too. The most important aim of this overview is the illustration of the principal causes of soil degradation in Iran, highlighting the important subjects for sustainable soil management. The overview also notes that our understanding about human-induced soil degradation in Iran is still at a rudimentary stage; therefore, some research topics need more attention in future.