بررسي برخي خصوصيات شيميايي خاك در دو توده جنگلي گلازني‌شده و كم‌تر دست خورده در زاگرس شمالي (مطالعةموردي: جنگل‌‌هاي حوزه بانه، استان كردستان)

Investigating Some Chemical Soil Properties in the Pollarded and Less-disturbed Forest Stands in the Northern Zagros (Case study: Baneh forest, Kurdistan)

زﻣﯿﻨﻪ و ﻫﺪف: ﺟﻨﮕﻞﻫﺎي ﺑﻠﻮط زاﮔﺮس ﺷﻤﺎﻟﯽ از دﯾﺮﺑﺎز ﺟﻬﺖ ﺳﺮﺷﺎﺧﻪزﻧﯽ و ﺗﻌﻠﯿﻒ دام ﻣﻮرد اﺳﺘﻔﺎده ﺑﻮده و در ﻧﻬﺎﯾﺖ ﺗﻮﺳﻂ ﻣﺮدم ﺑﻮﻣﯽ ﻣﻮرد ﺗﺨﺮﯾﺐ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. از اﯾﻦرو در اﯾﻦ ﭘﮋوﻫﺶ ﺗﻼش ﺷﺪ ﺗﺎ ﺗﺄﺛﯿﺮ ﺳﺮﺷﺎﺧﻪزﻧﯽ درﺧﺘﺎن )ﮔﻼزﻧﯽ( ﺑﺮ ﺑﺮﺧﯽ ﺧﺼﻮﺻﯿﺎت ﺷﯿﻤﯿﺎﯾﯽ ﺧﺎك ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﯿﺮد. ﻣﻮاد و روشﻫﺎ: دو ﻣﻨﻄﻘﻪ ﺟﻨﮕﻠﯽ ﺑﺎ ﺣﺪاﻗﻞ ﻓﺎﺻﻠﻪ و ﺑﯿﺶﺗﺮﯾﻦ ﺗﺸﺎﺑﻪ ﺷﺎﻣﻞ ﻣﻨﻄﻘﻪ ﮐﻢﺗﺮ دﺳﺖﺧﻮرده ﺑﻪ ﻋﻨﻮان ﻣﻨﻄﻘﻪ ﺷﺎﻫﺪ و ﺗﻮدهي دﯾﮕﺮي ﮐﻪ ﻫﺮ ﺳﻪ ﺳﺎل ﯾﮏﺑﺎر ﺟﻬﺖ ﺗﻌﻠﯿﻒ دام ﺳﺮﺷﺎﺧﻪ زﻧﯽ ﻣﯽﺷﻮد، اﻧﺘﺨﺎب ﺷﺪﻧﺪ. در ﻫﺮ ﺗﻮده 10 ﻧﻤﻮﻧﻪ ﺗﺮﮐﯿﺒﯽ ﺧﺎك از ﻋﻤﻖ ﺳﺎﻧﺘﯽﻣﺘﺮي و در زﯾﺮ ﺗﺎج درﺧﺘﺎن ﺑﺮداﺷﺖ ﺷﺪ. درﻧﻬﺎﯾﺖ درﺻﺪ ﮐﺮﺑﻦ آﻟﯽ، ﻧﯿﺘﺮوژن، ﭘﺘﺎﺳﯿﻢ، ﻓﺴﻔﺮ، ﮐﻠﺴﯿﻢ و ﻣﻨﯿﺰﯾﻢ و ﻫﻤﭽﻨﯿﻦ 0-15 ﻧﺴﺒﺖ C/N ﺧﺎك اﯾﻦ دو ﻣﻨﻄﻘﻪ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﯾﺎﻓﺘﻪﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﺑﻪ ﺟﺰ ﻧﺴﺒﺖ C/N و ﻣﯿﺰان ﻣﻨﯿﺰﯾﻢ، ﺳﺎﯾﺮ ﻋﻨﺎﺻﺮ در دو ﻣﻨﻄﻘﻪ داراي اﺧﺘﻼف ﻣﻌﻨﯽ دار ﺑﻮدﻧﺪ. ﻣﯿﺰان ﮐﻠﺴﯿﻢ و اﺳﯿﺪﯾﺘﻪ در ﻣﻨﻄﻘﻪ ﮔﻼزﻧﯽ ﺷﺪه ﻧﺴﺒﺖ ﺑﻪ ﺷﺎﻫﺪ ﺑﯿﺶﺗﺮ ﺑﻮد، در ﺣﺎﻟﯽﮐﻪ درﺻﺪ ﮐﺮﺑﻦ آﻟﯽ و ﻧﯿﺘﺮوژن، ﭘﺘﺎﺳﯿﻢ، ﻓﺴﻔﺮ و ﻫﺪاﯾﺖ اﻟﮑﺘﺮﯾﮑﯽ ﻧﺴﺒﺖ ﺑﻪ ﻣﻨﻄﻘﻪ ﺷﺎﻫﺪ، ﮐﻢﺗﺮ ﺑﻮد. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﻃﺒﻖ ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه از اﯾﻦ ﺗﺤﻘﯿﻖ، ﺣﻔﻆ درﺧﺘﺎن و ﻋﺪم ﺳﺮﺷﺎﺧﻪزﻧﯽ آنﻫﺎ در ﻣﻨﻄﻘﻪ ﺷﺎﻫﺪ، ﺳﺒﺐ ﺷﮑﻞﮔﯿﺮي ﺷﺮاﯾﻂ ﺧﺎﮐﯽ ﻣﻨﺎﺳﺐ ﺗﺮي در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺗﻮده ﮔﻼزﻧﯽ ﺷﺪه ﻣﯽﮔﺮدد. ﺑﺎ ﮔﻼزﻧﯽ ﺗﻮدهﻫﺎي ﺑﻠﻮط و ﺑﺮداﺷﺖ ﺷﺎخ و ﺑﺮگ آنﻫﺎ از ﺟﻨﮕﻞ و ﻋﺪم ﺑﺮﮔﺸﺖ آنﻫﺎ ﺑﻪ ﺧﺎك ﺟﻨﮕﻠﯽ، ورود ﻣﻮاد آﻟﯽ ﺑﻪ ﺧﺎك ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ و اﯾﻦ ﺑﺮ روي ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ ﺧﺎك ﻣﻨﺎﻃﻖ ﺟﻨﮕﻠﯽ ﺗﺄﺛﯿﺮ ﻣﻨﻔﯽ ﮔﺬاﺷﺘﻪ و در دراز ﻣﺪت ﺑﺎﻋﺚ ﻓﻘﺮ ﻏﺬاﯾﯽ ﺧﺎك ﺧﻮاﻫﺪ ﺷﺪ.

Background and Objectives: A Northern Zagros oak forests have been pollarded since a long time ago and finally they have been destroyed by forest dwellers. This study was aimed to investigate the effect of pollarding on some soil chemical properties. Method: Two adjacent oak forest stands with similar physiography were selected including a less-disturbed area (as control stand) and pollarded stands that it periodically pollarded once every three years. 10 composite soil samples under the tree crown have been taken from 0-15 cm soil depth of each area. Finally, soil organic carbon, total nitrogen, C/N ratio, phosphorus, potassium, calcium, magnesium, pH and EC were analyzed. Findings: The results showed that all soil factors had significant differences in theses area except magnesium and C/N ratio. The amount of calcium and pH increased in pollarded area compare with control while soil organic carbon, total nitrogen, phosphorus, potassium and EC decreased. Discussion and Conclusion: The results of this study showed that preservation of trees and stop pollarding trees in control area can produce a better soil condition compare with pollard stands. People use trees foliage to feeding livestock by oak pollarding in this forest so that these pollarding activities of local dwellers can reduce the amount of soil organic matter content and soil nutrient reserves. The decreasing of soil nutrient reserves will be very harmful to conserve the soil fertility and productivity.