ارزيابي تغييرات ردپاي آب محصولات زراعي حوضه درياچه اروميه با استفاده از روش LMDI

Evaluation of Water Footprint of Crop Production Variability in Lake Urmia Basin using LMDI Method

شاخص­ هاي مؤثري مانند ردپاي آب لازم است در تخصيص بهينه منابع آب مدنظر قرار گيرند. در اين مطالعه ازﺷﺎﺧﺺ ردﭘﺎي آب ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﻣﺼﺎرف ﻣﺴﺘﻘﯿﻢ و ﻏﯿﺮﻣﺴﺘﻘﯿﻢ آب در ﺳﻪ ﺑﺨﺶ ﻣﻨﺎﺑﻊ آب آﺑﯽ، ﺳﺒﺰ و ﺧﺎﮐﺴﺘﺮي، ﺑﻪﻣﻨﻈﻮر ﺑﺮآورد ﻣﯿﺰان ﮐﻞ آب ﻣﺼﺮﻓﯽ ﺗﻮﺳﻂ ﻣﺤﺼﻮﻻت زراﻋﯽ در ﺣﻮﺿﻪ درﯾﺎﭼﻪ اروﻣﯿﻪ اﺳﺘﻔﺎده ﮔﺮدﯾﺪ. ﺟﻬﺖ ﺗﺤﻠﯿﻞ ﺟﺪاﮔﺎﻧﻪ ﻋﻮاﻣﻞ ﻣﺆﺛﺮ در روﻧﺪ ﺗﻐﯿﯿﺮات ردﭘﺎي آب، روش LMDI )ﺷﺎﺧﺺ ﻟﮕﺎرﯾﺘﻢ ﻣﯿﺎﻧﮕﯿﻦ اﻧﺤﺮاﻓﺎت( ﺑﻪﮐﺎر ﮔﺮﻓﺘﻪ ﺷﺪ. اﯾﻦ ﺷﺎﺧﺺ ﻣﺠﻤﻮع وزﻧﯽ ﻧﺮخ ﺗﻐﯿﯿﺮات ﻧﺴﺒﯽ ﭘﺎراﻣﺘﺮﻫﺎي ﻣﺆﺛﺮ را ﻧﺸﺎن ﻣﯽدﻫﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻋﻠﯽرﻏﻢ روﻧﺪ ﮐﺎﻫﺸﯽ در ﻫﺮ ﺳﻪ ﺟﺰء ردﭘﺎي آب ﻣﺤﺎﺳﺒﻪ ﺷﺪه در ﻃﻮل ﺳﺎلﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ )2003-2010(، ﺗﻐﯿﯿﺮات ﻧﺎﻣﻨﻈﻤﯽ در ﻣﯿﺰان ﻫﺮ ﺟﺰء ﺳﻪﮔﺎﻧﻪ ردﭘﺎي آب در ﻃﯽ دوره ﻣﺬﮐﻮر وﺟﻮد دارد. ﻋﺎﻣﻞﻫﺎي ﺳﯿﺴﺘﻢﻫﺎي آﺑﯿﺎري و ﻧﺤﻮه ﻓﻌﺎﻟﯿﺖﻫﺎي ﮐﺸﺎورزي در ﻣﻨﻄﻘﻪ ﺑﻪﻋﻨﻮان ﻋﻮاﻣﻞ اﻓﺰاﯾﻨﺪه و ﻋﻤﻠﮑﺮد ﮔﯿﺎه ﺑﻪﻋﻨﻮان ﻋﺎﻣﻞ ﮐﺎﻫﻨﺪه در ﺗﻐﯿﯿﺮات ردﭘﺎي آب ﺷﻨﺎﺧﺘﻪ ﺷﺪﻧﺪ. ﺑﯿﺸﺘﺮﯾﻦ ﻣﻘﺪار ردﭘﺎي آب ﮐﻞ ﻣﺮﺑﻮط ﺑﻪ ﺳﺎل 2004 ﺑﻮده ﮐﻪ در آن ﻣﻘﺎدﯾﺮ ردﭘﺎي آب آﺑﯽ، آب ﺳﺒﺰ و آب ﺧﺎﮐﺴﺘﺮي ﺑﻪﺗﺮﺗﯿﺐ 23419، 8832 و 2437 ﻣﺘﺮﻣﮑﻌﺐ ﺑﺮ ﺗﻦ ﻣﯽﺑﺎﺷﺪ. ﻫﻤﭽﻨﯿﻦ ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار ردﭘﺎي آب ﮐﻞ در ﺳﺎل 2006 ﻣﺸﺎﻫﺪه ﺷﺪ و ﻣﻘﺎدﯾﺮ ردﭘﺎي آب آﺑﯽ، آب ﺳﺒﺰ و آب ﺧﺎﮐﺴﺘﺮي در اﯾﻦ ﺳﺎل ﺑﻪﺗﺮﺗﯿﺐ 7562 ،19056 و 2076 ﻣﺘﺮﻣﮑﻌﺐ ﺑﺮ ﺗﻦ اﺳﺖ.

The effective indices such as water footprint should be considered in optimal allocation of water resources. In this study, the water footprint index with considering the direct and indirect water consumptions in three components of blue, green and grey water resources was applied to evaluate the total amount of water consumption in crop production of Lake Urmia basin. The LMDI (Logarithmic mean divisia index) approach was applied to determine the impact of the different factors on the variability of water footprint. The LMDI index showed the weighted sum of relative changes in the effective parameters. According to the results, although a reduction trend in the calculated water footprint components during the studied years (2003-2010) was observed, there were some irregular trends and changes in the amount of each component of water footprint at the same period. Irrigation systems and agricultural activities in the region were identified as increasing parameters while crop yield was a decreasing parameter in the water footprint changes. The maximum amount of total water footprint was related to 2004, in which the blue, green and grey water footprint values were 23419, 8832 and 2437 m3 ton-1, respectively. Also, the minimum amount of total water footprint was related to 2006, in which the blue, green and grey water footprint values were 19056, 7562 and 2076 m3 ton-1, respectively.