مقايسه مقدار ذخيره كربن خاك در گونه‌هاي پهن‌برگ و سوزني‌برگ، مطالعه موردي: آبخوان كوهدشت

Comparison of soil carbon stock in broadleaved and coniferous tree species, case study:Kuhdasht Aquifer

ﺗﺮاﮐﻢ دي اﮐﺴﯿﺪ ﮐﺮﺑﻦ اﺗﻤﺴﻔﺮ در اﺛﺮ ﻓﻌﺎﻟﯿﺖ ﻫﺎي اﻧﺴﺎﻧﯽ، روﻧﺪ ﮔﺮم ﺷﺪن ﮐﺮه زﻣﯿﻦ را ﺑﺴﯿﺎر اﻓﺰاﯾﺶ داده اﺳﺖ. ﺟﻨﮕﻞ ﮐﺎري ﯾﮑﯽ از راﻫﮑﺎرﻫﺎي ﻣﺆﺛﺮ ﺑﺮاي ﺟﺬب دي اﮐﺴﯿﺪ ﮐﺮﺑﻦ و اﻓﺰاﯾﺶ ذﺧﯿﺮه ﮐﺮﺑﻦ در ﺑﻮم ﺳﺎزﮔﺎن ﺧﺸﮑﯽ و ﮐﺎﻫﺶ ﮔﺮﻣﺎﯾﺶ زﻣﯿﻦ اﺳﺖ. اﯾﻦ ﭘﮋوﻫﺶ، ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ﻣﻘﺎﯾﺴﻪ ﻣﯿﺰان ذﺧﯿﺮه ﮐﺮﺑﻦ ﺧﺎك در ﺗﻮده ﻫﺎي درﺧﺘﯽ ﻣﻨﻄﻘﻪ آﺑﺨﻮان ﮐﻮﻫﺪﺷﺖ و اراﺋﻪ ﺑﻬﺘﺮﯾﻦ ﻣﺪل رﮔﺮﺳﯿﻮﻧﯽ ذﺧﯿﺮه ﮐﺮﺑﻦ ﺑﺮ اﺳﺎس ﺗﻤﺎﻣﯽ ﻣﺸﺨﺼﻪ ﻫﺎي ﺧﺎك اﻧﺠﺎم ﮔﺮﻓﺖ. در ﻫﺮ ﯾﮏ از ﺗﻮده ﻫﺎي 20 ﺳﺎﻟﻪ اﻧﺠﯿﺮ، اﻧﺎر، ﭘﺴﺘﻪ، ﺑﺎدام زراﻋﯽ و ﺳﺮو ﻧﻘﺮه اي و ﻣﺮﺗﻊ ﺷﺎﻫﺪ، ﺗﻌﺪاد 10 ﮐﺮت 5×5 ﻣﺘﺮ ﺑﻪ ﺻﻮرت ﺗﺼﺎدﻓﯽ اﻧﺘﺨﺎب و داﺧﻞ ﻫﺮ ﮐﺮت از ﻋﻤﻖ ﻫﺎي ﺻﻔﺮ ﺗﺎ 10-30 ،10 و 30-50 ﺳﺎﻧﺘﯽ ﻣﺘﺮي ﺧﺎك، ﻧﻤﻮﻧﻪ ﺑﺮداري اﻧﺠﺎم و ﻣﺸﺨﺼﻪ ﻫﺎي ﺧﺎﮐﺸﻨﺎﺳﯽ )ﺑﺎﻓﺖ ﺧﺎك، ﮐﺮﺑﻦ آﻟﯽ، وزن ﻣﺨﺼﻮص ﻇﺎﻫﺮي، ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ، درﺻﺪ آﻫﮏ و اﺳﯿﺪﯾﺘﻪ ﺧﺎك( اﻧﺪازه ﮔﯿﺮي ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ ﻣﻘﺪار ﻣﯿﺎﻧﮕﯿﻦ ذﺧﯿﺮه ﮐﺮﺑﻦ ﺧﺎك در ﮔﻮﻧﻪ ﭘﺴﺘﻪ )54/94 ﺗﻦ در ﻫﮑﺘﺎر( ﺑﻪ ﻃﻮر ﻣﻌﻨﯽ داري )P<0/01( ﺑﯿﺸﺘﺮ از اﻧﺠﯿﺮ )50/23 ﺗﻦ در ﻫﮑﺘﺎر(، ﺑﺎدام زراﻋﯽ )31/53 ﺗﻦ در ﻫﮑﺘﺎر(، اﻧﺎر )27/09 ﺗﻦ در ﻫﮑﺘﺎر(، ﺳﺮو ﻧﻘﺮه اي )24/17 ﺗﻦ در ﻫﮑﺘﺎر( و ﻣﺮﺗﻊ ﺷﺎﻫﺪ )9/01 ﺗﻦ در ﻫﮑﺘﺎر( اﺳﺖ. در ﺑﯿﻦ ﺗﻮده ﻫﺎي ﻣﻮرد ﺑﺮرﺳﯽ، اﺟﺰا ﺗﺸﮑﯿﻞ دﻫﻨﺪه ﺑﺎﻓﺖ ﺧﺎك، ﻣﻘﺪار اﺳﯿﺪﯾﺘﻪ، ﮐﺮﺑﻦ آﻟﯽ، ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ و وزن ﻣﺨﺼﻮص ﻇﺎﻫﺮي ﺧﺎك، اﺧﺘﻼف ﻣﻌﻨﯽ داري را ﻧﺸﺎن ﻣﯽ دﻫﺪ )P<0/01(. ﻫﻤﭽﻨﯿﻦ، ﻧﺘﯿﺠﻪ رﮔﺮﺳﯿﻮن ﮔﺎم ﺑﻪ ﮔﺎم ﻧﺸﺎن داد ﮐﻪ ﺑﺎﻓﺖ ﺧﺎك و ﻣﻘﺪار اﺳﯿﺪﯾﺘﻪ ﺑﻪ ﺗﺮﺗﯿﺐ از ﻣﻬﻤﺘﺮﯾﻦ اﺟﺰاء ﺗﺄﺛﯿﺮﮔﺬار ﺑﺮ ﻣﻘﺪار ذﺧﯿﺮه ﮐﺮﺑﻦ ﺧﺎك ﺑﻮدﻧﺪ.

Increased concentration of atmospheric carbon dioxide due to human activities has resulted in accelerated global warming process. Forestation is the most effective way to absorb atmospheric carbon dioxide and store it in terrestrial ecosystems in order to reduce and mitigate global warming. This study aimed to investigate the comparison of soil carbon sequestration in various stands in ​​Kuhdasht Aquifer and to present the best regression model for carbon sequestration based on all soil characteristics. In each stand (20-year old) of Ficus carica, Punica granatum, Pistacia vera, Amygdalus lycioides and Cupressus arizonica species as well as control rangeland, a number of 10 sample plots (5×5 m) were randomly selected and soil samples were taken in each plot at 0-10, 10-30 and 30-50 cm depths. All soil samples were transferred to the laboratory in order to measure soil characteristics including soil texture, organic carbon, bulk density, electrical conductivity, lime percentage and soil acidity. The results showed that the highest value of carbon sequestration in soil of Pistacia vera stand (54.94 tha-1) significantly (P <%1) higher compared to other stands, followed by Ficus carica (50.23 tha-1), Amygdalus lycioides (31.53 tha-1), Punica granatum (27.09 tha-1), Cupressus arizonica (24.17 tha-1) and control rangeland (9.01 tha-1) stands. Results also showed significant differences (P <%1) between the studied stands in terms of soil texture, acidity, organic carbon, electrical conductivity and soil bulk density. Also, the result of stepwise regression indicated that soil texture and acidity were the most important components affecting soil carbon sequestration, respectively.