تعيين خسارت اقتصادي ناشي از فرسايش خاك در كاربري‌هاي مختلف اراضي (مطالعۀ موردي: حوزۀ آبخيز بهشت آباد، استان چهارمحال و بختياري)

Determination of economic loss of soil erosion in different land uses (Case study: Beheshtakad watershed basin in Chaharmahal and Bakhtiari province)

ﻓﺮﺳﺎﯾﺶ ﺧﺎك ﺗﻮأم ﺑﺎ رﺷﺪ ﺟﻤﻌﯿﺖ، ﺗﺄﻣﯿﻦ آب، ﻏﺬا و اﻧﺮژي، ﺗﻐﯿﯿﺮ اﻗﻠﯿﻢ و ﮐﺎﻫﺶ ﺗﻨﻮع زﯾﺴﺘﯽ ﯾﮑﯽ از ﻣﺸﮑﻼت ﺑﺰرگ ﻣﺤﯿﻂ زﯾﺴﺘﯽ ا ﺳﺖ. ﭘﯿﺎﻣﺪﻫﺎي ﻧﺎ ﺷﯽ از ﻓﺮ ﺳﺎﯾﺶ ﺧﺎك را ﻣﯽﺗﻮان ﺑﺎ اﺑﻌﺎد ﻣﺨﺘﻠﻔﯽ ﻣﻮرد ﺑﺮر ﺳﯽ ﻗﺮار داد. از ﺑﻌﺪ ﻣﮑﺎﻧﯽ ﻫﺰﯾﻨﻪﻫﺎي ﻣﺨﺘﻠﻒ ﻓﺮ ﺳﺎﯾﺶ ﺧﺎك ﺑﻪ دو دﺳـﺘﻪ ﻫﺰﯾﻨﻪﻫﺎي درونﻣﻨﻄﻘﻪاي و ﺑﺮونﻣﻨﻄﻘﻪاي ﻗﺎﺑﻞ ﺗﻘﺴـﯿﻢاﻧﺪ. ﻓﺮﺳـﺎﯾﺶ ﺧﺎك ﺗﺄﺛﯿﺮ ﻣﻨﻔﯽ ﻣﺴـﺘﻘﯿﻢ و ﻏﯿﺮ ﻣﺴـﺘﻘﯿﻢ ﺑﺮ ﭼﺮﺧﮥ ﺗﻮﻟﯿﺪ و اﻗﺘﺼﺎد دارد. ﻫﺪف اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮآورد و ﻣﻘﺎﯾﺴﮥ ﺧﺴﺎرت اﻗﺘﺼﺎدي ﻣﺴﺘﻘﯿﻢ و ﻏﯿﺮﻣﺴﺘﻘﯿﻢ ﻓﺮﺳﺎﯾﺶ ﺧﺎك در ﮐﺎرﺑﺮيﻫﺎي ﻣﺨﺘﻠﻒ اراﺿﯽ در ﺣﻮزة آﺑﺨﯿﺰ ﺑﻬﺸﺖ آﺑﺎد اﺳﺖ. ﺑﻪ اﯾﻦ ﻣﻨﻈﻮر، ﺧﺴﺎرت ﻣﺴﺘﻘﯿﻢ ﻓﺮﺳﺎﯾﺶ ﺧﺎك در ﮐﺎرﺑﺮيﻫﺎي ﻣﺨﺘﻠﻒ اراﺿﯽ ﺑﺮ اﺳﺎس روش ﺟﺎﯾﮕﺰﯾﻨﯽ ﻋﻨﺎﺻﺮ اﺻﻠﯽ ﺣﺎﺻﻞﺧﯿﺰي ﺧﺎك ﺑﺎ ﮐﻮدﻫﺎي ﺷﯿﻤﯿﺎﯾﯽ ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ﺑﻪ ﻣﻨﻈﻮر ﺑﺮآورد ﻣﻘﺪار ﺧﺎك ﻓﺮﺳﻮده ﺷﺪه از ﺳﻄﺢ ﮐﺎرﺑﺮيﻫﺎي ﻣﺨﺘﻠﻒ از ﻧﺘﺎﯾﺞ ﻣﺪل SWAT در اﯾﻦ ﻣﻨﻄﻘﻪ اﺳﺘﻔﺎده ﺷﺪ. ﺧﺴﺎرت ﻏﯿﺮﻣﺴﺘﻘﯿﻢ ﻓﺮﺳﺎﯾﺶ ﺑﺮ اﺳﺎس ﻫﺰﯾﻨﮥ ﻣﺼﺮف ﺷﺪه ﺑﺮاي اﺣﺪاث ﺑﻨﺪﻫﺎي اﺻــﻼﺣﯽ ﺑﻪ ﻋﻼوه ﺧﺴــﺎرت ﻧﺎﺷــﯽ از رﺳــﻮبﮔﺬاري در ﭘﺸــﺖ ﺳــﺪﻫﺎي ﻣﺨﺰﻧﯽ ﺑﺮآورد ﺷــﺪ. از ﺧﺴــﺎرتﻫﺎي ﻣﺮﺑﻮط ﺑﻪ ارزشﻫﺎي ﻃﺒﯿﻌﯽ و زﯾ ﺴﺘﯽ ﺻﺮفﻧﻈﺮ ﺷﺪ. ﻃﺒﻖ ﻧﺘﺎﯾﺞ، ﺑﯿﺶﺗﺮﯾﻦ ﻣﯿﺰان ﺧ ﺴﺎرت اﻗﺘ ﺼﺎدي ﻧﺎ ﺷﯽ از ﻓﺮ ﺳﺎﯾﺶ ﺧﺎك ﻣﺮﺑﻮط ﺑﻪ ﮐﺎرﺑﺮي ﮐﺸﺖ دﯾﻢ ﻣﻌﺎدل 56 ﻣﯿﻠﯿﻮن رﯾﺎل در ﻫﺮ ﻫﮑﺘﺎر در ﺳﺎل ﺑﺮآورد ﺷﺪ؛ ﻋﻠﺖ را ﻣﯽﺗﻮان ﻗﺮارﮔﯿﺮي اﯾﻦ اراﺿﯽ در ﺷﯿﺐﻫﺎي زﯾﺎد و ﻋﻤﻠﯿﺎت ﻧﺎدرﺳــﺖ ﮐﺸــﺎورزي در ﻣﻨﻄﻘﻪ داﻧﺴــﺖ. ﻫﻤﭽﻨﯿﻦ، ﮐﻤﺘﺮﯾﻦ ﺧﺴــﺎرت ﺑﺮآوردي ﻣﺮﺑﻮط ﺑﻪ ﮐﺎرﺑﺮي ﺑﺎﻏﯽ ﺑﺎ 5/4 ﻣﯿﻠﯿﻮن رﯾﺎل در ﻫﮑﺘﺎر در ﺳﺎل ﺑﻮد ﮐﻪ اﻫﻤﯿﺖ ﺗﺎج ﭘﻮ ﺷﺶ درﺧﺘﺎن و رﻋﺎﯾﺖ ﺷﯿﺐ ﻣﻨﺎ ﺳﺐ در اﯾﺠﺎد ﺑﺎغ در ﺣﻔﺎﻇﺖ ﺧﺎك را ﻧ ﺸﺎن ﻣﯽدﻫﺪ. در اﯾﻦ ﺣﻮ ﺿﻪ ﭼﺮاي ﻣﻔﺮط و ﺑﻬﺮهﺑﺮداري ﻧﺎﻣﻨﺎ ﺳﺐ از ﻣﺮاﺗﻊ ﺳﺒﺐ ﺑﺎﻻ رﻓﺘﻦ ﻧﺮخ ﻓﺮ ﺳﺎﯾﺶ و ﺗﻮﻟﯿﺪ ر ﺳﻮب در ﻣﺮاﺗﻊ ﺑﺎﻻد ﺳﺖ و درﻧﺘﯿﺠﻪ 33/3 ﻣﯿﻠﯿﻮن رﯾﺎل ﺧﺴﺎرت ﻓﺮﺳﺎﯾﺶ از ﻫﺮ ﻫﮑﺘﺎر در اﯾﻦ ﮐﺎرﺑﺮي ﻣﯽﺷﻮد.

Soil erosion along environmental problems. The consequences of soil erosion can be examined from a variety of perspectives.the cost of soil erosion is divided into two categories of on-site and off-site costs. Soil erosion affects the production cycle and economics directly and indirectly. The purpose of this study was to estimate and compare direct and indirect economic losses of soil erosion in different land uses in the Beheshtabad Basin.To achive this, first sediment production by each landuse was initially determined by using SWAT model. NS and R² model coefficients for calibration were 0.72,0.73, and 0.66,0.71 for validation. Then direct loss of erosion was calculated based on the method of replacing the main soil organic fertilizer (NPK) by chemical fertilizers and indirect loss of erosion based on the loss caused by sedimentation behind the check dams inside the basin and reservoir dams outside the basin. According to the results, the highest amount of economic loss of soil erosion was related to rainfed farms equivalent to 56 million Rials per hectare Due to the fact that these lands are located on high slopes and also incorrect agricultural operations .The least amount was related to gardens,equal to 4.5 million-rials/hectare that indicated the importance of trees crown covering and observing the proper slope in the construction of gardens in the soil conservation. In this basin,excess grazing and improper utilization of rangelands have led to high erosion rate and sediment production in upstream rangelands and 3.33 million-Rials/hectare economic losses of erosion in this land use.