كليدواژه :
ﺟﻨﮕﻞﮐﺎري , ﭘﻬﻦﺑﺮگ , ﺳﻮزﻧﯽﺑﺮگ , زﯾﺘﻮده ﻣﯿﮑﺮﺑﯽ , ﻣﺸﺨﺼﻪ ﻫﺎي ﺧﺎك
چكيده فارسي :
ﺳﺎﺑﻘﻪ و ﻫﺪف: ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ ، شيميايي و زيستي خاك مي توانند به ﻋﻨﻮان ﻣﻬﻢ ﺗﺮﯾﻦ ﻣﺸﺨﺼﻪﻫﺎي ﺷﺎﺧﺺ ﮐﯿﻔﯿﺖ ﺧﺎك در ارﺗﺒﺎط ﺑﺎ ﺗﻐﯿﯿﺮ ﭘﻮﺷﺶ اراﺿﯽ و ﺗﻐﯿﯿﺮ اﻗﻠﯿﻢ ﻣﺪ ﻧﻈﺮ ﻗﺮار ﮔﯿﺮﻧﺪ .ﺟﻨﮕﻞﮐﺎري ﺑﺎ ﮔﻮﻧﻪﻫﺎي ﺑﻮﻣﯽ و ﻏﯿﺮﺑﻮﻣﯽ ﺟﻬﺖ ﺑﺎزﺳﺎزي اراﺿﯽ ﺗﺨﺮﯾﺐﯾﺎﻓﺘﻪ ﻃﺒﯿﻌﯽ ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ .اﺻﻮﻻً ﺑﺮاي ﻣﻄﺎﻟﻌﻪ ﮐﯿﻔﯿﺖ ﺧﺎك وﯾﮋﮔﯽ ﻫﺎﯾﯽ ﮐﻪ ﺑﻪ ﺗﻐﯿﯿﺮات ﻣﺤﯿﻄﯽ ﺣﺴﺎسﺗﺮ ﻫﺴﺘﻨﺪ در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﻣﯽﺷﻮﻧﺪ .وﯾﮋﮔﯽﻫﺎي زﯾﺴﺘﯽ و ﺑﯿﻮﺷﯿﻤﯿﺎﯾﯽ ﺧﺎك از ﺟﻤﻠﻪ ﺷﺎﺧﺺ ﻫﺎﯾﯽ ﻫﺴﺘﻨﺪ ﮐﻪ در ﮐﻮﺗﺎه ﻣﺪت ﺑﻪ ﺗﻐﯿﯿﺮات ﻣﺤﯿﻄﯽ و ﻣﺪﯾﺮﯾﺖ اﮐﻮﺳﯿﺴﺘﻢ واﮐﻨﺶ ﻧﺸﺎن ﻣﯽدﻫﻨﺪ .ﺧﺎك ﺑﻪ ﻋﻨﻮان ﺑﺴﺘﺮ روﯾﺸﮕﺎه، ﺷﺪﯾﺪاً ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﻧﻮع ﮔﻮﻧﻪ درﺧﺘﯽ اﻧﺘﺨﺎﺑﯽ ﻗﺮار دارد .ﺗﻮﺟﻪ ﺑﻪ ﻧﻮع ﮔﻮﻧﻪ و اﺛﺮ آن ﺑﺮ ﻣﺸﺨﺼﻪﻫﺎي ﮐﯿﻔﯽ ﺧﺎك ﺑﻪ ﻋﻨﻮان راﻫﮑﺎر ﻣﺪﯾﺮﯾﺘﯽ ﻣﻮﺟﺐ ﺣﻔﻆ ﮐﻤﯿﺖ و ﭘﺎﯾﺪاري ﻃﻮﻻﻧﯽﻣﺪت ﻋﺮﺻﻪﻫﺎي ﺟﻨﮕﻞﮐﺎري ﻣﯽﺷﻮد.
ﻣﻮاد و روش ﻫﺎ: ﺑﻪ ﻣﻨﻈﻮر ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ ﭘﻮﺷﺶﻫﺎي ﻣﺨﺘﻠﻒ ( اﻗﺎﻗﯿﺎ، زﺑﺎنﮔﻨﺠﺸﮏ، ﺳﺮو ﻧﻘﺮهاي و ﮐﺎج ﺗﻬﺮان ) اراﺿﯽ ﺑﺮ ﺷﺎﺧﺺ ﻫﺎي ﻓﯿﺰﯾﮑﻮﺷﯿﻤﯿﺎﯾﯽ، ﻣﯿﮑﺮوﺑﯿﻮﻟﻮژي و ﺗﺼﺎﻋﺪ ﮔﺎز دي اﮐﺴﯿﺪﮐﺮﺑﻦ ﺧﺎك، ﭘﮋوﻫﺶ ﺣﺎﺿﺮ در ﻣﺤﺪوده ﭘﺎرك ﭼﯿﺘﮕﺮ ﻣﻮرد ﺗﻮﺟﻪ ﻗﺮار ﮔﺮﻓﺖ .ﻧﻤﻮﻧﻪﺑﺮداري از ﻻﯾﻪ آﻟﯽ ( ﻻﺷﺒﺮگ)و ﻣﻌﺪﻧﯽ ( 20-0 ﺳﺎﻧﺘﯽﻣﺘﺮي) خاك به ﺻﻮرت ﺗﺼﺎدﻓﯽ ﺳﯿﺴﺘﻤﺎﺗﯿﮏ اﻧﺠﺎم ﭘﺬﯾﺮﻓﺖ ﻣﺸﺨﺼﻪﻫﺎي ﮐﯿﻔﯽ ﻻﺷﺒﺮگ ( ﮐﺮﺑﻦ و ﻧﯿﺘﺮوژن) جرم مخصوص ظاهري ، بافت رﻃﻮﺑﺖ، اﺳﯿﺪﯾﺘﻪ، ﮐﺮﺑﻦ آﻟﯽ، ﻧﯿﺘﺮوژن ﮐﻞ، ﻧﯿﺘﺮات، آﻣﻮﻧﯿﻮم، زﯾﺘﻮده ﻣﯿﮑﺮوﺑﯽ ﮐﺮﺑﻦ و ﻧﯿﺘﺮوژن، ﺗﺼﺎﻋﺪ دي اﮐﺴﯿﺪﮐﺮﺑﻦ و ( ﺟﺮﯾﺎن آن در دﻣﺎ و رﻃﻮﺑﺖﻫﺎي ﻣﺨﺘﻠﻒ ) در ﻣﺤﯿﻂ آزﻣﺎﯾﺸﮕﺎه اﻧﺪازهﮔﯿﺮي ﺷﺪ.
ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻫﻤﻪ ﻣﺸﺨﺼﻪﻫﺎي ﻓﯿﺰﯾﮑﻮﺷﯿﻤﯿﺎﯾﯽ ﺧﺎك و ﻻﺷﺒﺮگ ( ﺑﻪ ﺟﺰ ﮐﺮﺑﻦ) در ﺗﻮدهﻫﺎي ﺟﻨﮕﻠﯽ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺗﻔﺎوت آﻣﺎري ﻣﻌﻨﯽداري داﺷﺘﻨﺪ .ﻃﺒﻖ ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه، ﺑﯿﺶ ﺗﺮﯾﻦ ﻣﻘﺎدﯾﺮ ﻫﺮ ﯾﮏ از ﻣﺸﺨﺼﻪﻫﺎي دي اكسيد كربن متصاعد شده ( 1 ميلي گرم دي اكسيد كربن در متر مربع در روز )، زيتوده هاي ميكروبي كربن ( 510/31 ميلي گرم بر كيلوگرم ) و نيتروزن ( 0/13 ميلي كرم بر گرم ) خاك در توده جنگلي اقاقيا مشاهده شد. همجنين ، ﺑﯿﺶ ﺗﺮﯾﻦ ﻣﯿﺰان ﺗﺼﺎﻋﺪ دي اﮐﺴﯿﺪﮐﺮﺑﻦ در ﺷﺮاﯾﻂ رﻃﻮﺑﺖ ﻋﺮﺻﻪ ﻣﺸﺎﻫﺪه ﺷﺪ و ﺑﺎ اﻓﺰاﯾﺶ دﻣﺎ ﻣﯿﺰان ﺗﺼﺎﻋﺪ اﻓﺰاﯾﺶ ﯾﺎﻓﺖ.
ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺗﻐﯿﯿﺮ ﻧﻮع ﭘﻮﺷﺶ اراﺿﯽ ﺗﺨﺮﯾﺐﯾﺎﻓﺘﻪ و ﺟﻨﮕﻞﮐﺎري ﺑﺎ ﮔﻮﻧﻪﻫﺎي ﭘﻬﻦﺑﺮگ و ﺳﻮزﻧﯽﺑﺮگ، در ﻣﻨﻄﻘﻪ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺑﺎﻋﺚ ﺑﻬﺒﻮد ﺷﺎﺧﺺﻫﺎي ﺣﺎﺻﻞﺧﯿﺰي، ﺑﻪ وﯾﮋه ﺷﺎﺧﺺﻫﺎي زﯾﺴﺘﯽ ﮐﯿﻔﯿﺖ ﺧﺎك ﺷﺪ .ﺑﺎﻻﺗﺮﯾﻦ ﺳﻄﻮح ﺗﻨﻔﺲ ﻣﯿﮑﺮﺑﯽ، زﯾﺘﻮده ﻣﯿﮑﺮﺑﯽ ﮐﺮﺑﻦ و ﻧﯿﺘﺮوژن در روﯾﺸﮕﺎه ﻫﺎي ﺟﻨﮕﻞﮐﺎري ﺷﺪه ﭘﻬﻦﺑﺮگ و ﮐﻢ ﺗﺮﯾﻦ ﻣﻘﺎدﯾﺮ آن ﻫﺎ در اراﺿﯽ ﺑﺎﯾﺮ و ﻓﺎﻗﺪ ﭘﻮﺷﺶ درﺧﺘﯽ ﻣﺸﺎﻫﺪه ﮔﺮدﯾﺪ .ﻧﺘﺎﯾﺞ ﺑﯿﺎﻧﮕﺮ آن اﺳﺖ ﮐﻪ ﺗﻐﯿﯿﺮ ﮐﺎرﺑﺮي اراﺿﯽ و ﻧﺎﺑﻮدي ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ اﮐﻮﺳﯿﺴﺘﻢ، ﺑﺎﻋﺚ اﻓﺖ ﺷﺪﯾﺪ ﺷﺎﺧﺺﻫﺎي ﻣﺬﮐﻮر در ﻣﻨﻄﻘﻪ ﭼﯿﺘﮕﺮ ﺷﺪه اﺳﺖ، ﺑﻨﺎﺑﺮاﯾﻦ ﺗﻐﯿﯿﺮ ﮐﺎرﺑﺮي اﻧﺠﺎم ﯾﺎﻓﺘﻪ ﺗﻬﺪﯾﺪي ﺑﺮ ﮐﯿﻔﯿﺖ و ﺳﻼﻣﺖ ﺧﺎك در ﻣﻨﻄﻘﻪ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ اﺳﺖ ﮐﻪ در ﻣﺪﯾﺮﯾﺖ اﮐﻮﺳﯿﺴﺘﻢﻫﺎي ﻃﺒﯿﻌﯽ ﺗﺨﺮﯾﺐﯾﺎﻓﺘﻪ ﺑﺎﯾﺪ ﺑﻪ اﯾﻦ ﻣﻮﺿﻮع ﺗﻮﺟﻪ ﺧﺎﺻﯽ ﺷﻮد
چكيده لاتين :
Background and Objectives: Soil physical, chemical and biological properties can be considered as the most important features of soil quality indices related to land cover and also climate changes. Afforestation with native and non-native species were employed for rehabilitation of natural degraded lands. Usually due to the study of soil quality, some properties are regarded that are more sensitive to environmental changes. Soil biological and biochemical properties are the features that response to environmental changes and ecosystem management in the short term. Soil as the site bed is affected by selected species type. Regarding to species type and its effect on soil quality properties is as management algorithm that is due to quantity preserve and long term stability of afforested areas.
Materials and Methods: To aim studying the effect of different land covers (Robinia pseudoacacia, Fraxinus excelsior, Cupressus arizonica and Pinus elderica) on soil physicalchemical, microbiological and CO2 emission characters, the present research was regraded in the Chitgar park. Sampling was done from the organic (litter) and mineral (0-20cm) layers using of the randomly systematic method. Litter quality properties (carbon and nitrogen), soil bulk density, texture, water content, pH, organic carbon, total nitrogen, nitrate, ammonium, carbon microbial biomass, nitrogen microbial biomass, CO2 emission (and their fluxes in different temperature and moisture regime) measured in the laboratory.
Results: Results is indicating the afforested stands had significantly different effects on the whole of the physical-chemical properties of soil and litter (except carbon content). According to our findings, the highest amount of CO2 emission (1 mg CO2 m-2 d-1), microbial biomass of carbon (510.31 mg kg-1) and nitrogen (0.13 mg kg-1) were belong to Robinia pseudoacacia stand. In addition, the maximum of CO2 emission was occurred in field capacity moisture regime and higher temperature.
Conclusion: The change of degraded land covers, afforestation with needle leaved and broad leaved species, improved the fertility indices, especially biological indices of soil quality in the study area. The highest amount of microbial respiration, microbial biomass of carbon and nitrogen were found under afforested site with broadleaved species and the least amount were detected in bare land. The results are indicated that the land use change and destroying of ecosystem plant covers is due to a severe reduction of mentioned indices in Chitgar region. So, land use change is a treat for soil health and quality in study area that must be considered in management of degraded natural ecosystem.
