International Symposium on
Drylands Ecology and Human Security
The Study of Ecological Degradation in Arid Regions of Iran
A.R. Keshtkar, A. Salajegheh & H.R. Keshtkar
Mountainous and Arid Regions Reclamation Department, Natural Resources Faculty, Tehran University, Iran
This paper investigated main factors of land and ecological degradation in Dahak river basin. The study area is located in the Lout Plain sand land (32° 25′ N, 58° 42′ E,) in the Northern part of Lout Plain, which belongs to the continental arid climate in the temperate zone. Mean annual precipitation is 155 mm, mean annual potential evaporation is 1375 mm, and the mean annual temperature is 15.9°C. The average annual wind speed is 3.4 m s− 1 and mean wind speed in the wind erosion season (summer) is 4.3 m s− 1. The thickness of the soil layer in the farmlands is about 30–45 cm and the soil consists mainly of coarse sand and silt; the C Horizon is sand aggraded during the Quaternary period. Crop monoculture dominates the cultivated land. In this system, the crop is planted at the end of April and harvested at the end of September, leaving the soil bare for about 7 months, from October through April of the following year. Wind erosion is very pronounced during the spring season. From the thawing of the frozen surface in mid-March until the sowing of crops at the end of April, the loose soil surface is dry and bare, and thus extremely susceptible to wind erosion In this region animal unit combinative are, camel 69.9%, sheep and goat 28.6% and cow 1.5% those 9 months of year graze in range. Dominant species in five plant types are Caligunum Fabago, Artemisia herba-alba, Peganum harmala, Salsola tomentosa, Seidlitzia rosmarinus, Haloxylon aphyllum and Alhaji camellorum. The studies show that camel over grazing, drought in recent years, wind erosion and socio-economic problems are main causes of ecological degradation in Dahak river basin.
Keywords: ecological, arid, Dahak, wind, erosion, Iran