تاثیر نوع پوشش اراضی جنگلی و مرتعی بر انباشتگی عناصر غذایی خاک در منطقه ییلاقی کجور

ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺑﺮرسی اﻧﺒﺎشتگی ﻋﻨﺎﺻﺮ ﻏﺬایی ﺗﺤﺖ ﭘﻮﺷﺶ ﻫﺎی ﮔﻴﺎهی ﻣﺨﺘﻠﻒ در روﻳﺸﮕﺎه ﻫﺎی جنگلی و ﻣﺮتعی ﻣﻨﻄﻘﻪ ﻛﺠﻮر ﻧﻮﺷﻬﺮ ﺑﺮرسی ﺷﺪه اﺳﺖ. ﺑﺮای رﺳﻴﺪن ﺑﻪ اﻳﻦ ﻫﺪف، ﻣﻴﺰان ﻋﻨﺎﺻﺮ ﻏﺬایی ﻻﺷﺒﺮگ و ذﺧﻴﺮه ﻋﻨﺎﺻﺮ ﻏﺬایی ﺧﺎک در دو ﻧﻮع روﻳﺸﮕﺎه ﻣﺮتعی ﺑﺎ ﭘﻮﺷﺶ ﻏﺎﻟﺐ stachys byzantina و rhamnus pallasii و ﻳﻚ روﻳﺸﮕﺎه جنگلی ﺑﺎ ﮔﻮﻧﻪ ﻏﺎﻟﺐ ﺑﻠﻮط )quercus castaneifolia( در ﻣﻨﻄﻘﻪ ﻛﺠﻮر اﻧﺪازه ﮔﻴﺮی و ﻣﻮرد ﺑﺮرسی ﻗﺮار ﮔﺮﻓﺘﻪ ﺷﺪ. در ﻗﻄﻌﻪ ﻧﻤﻮﻧﻪ ﻫﺎ، ﺗﻌﺪاد 36 ﻧﻤﻮﻧﻪ ﺧﺎک از ﻋﻤﻖ 0-20 ﺳﺎنتی ﻣﺘﺮی و 36 ﻧﻤﻮﻧﻪ ﻻﺷﺒﺮگ ﺟﻤﻊ آوری ﺷﺪ. ﻧﻤﻮﻧﻪ ﻫﺎی ﺧﺎک و ﻻﺷﺒﺮگ در ﻗﻄﻌﻪ ﻧﻤﻮﻧﻪ ﻫﺎ ﺟﻤﻊ آوری و ﻣﻘﺪار ﻋﻨﺎﺻﺮ k ،mg ،ca ،n ،c و pدر ﻻﺷﺒﺮگ و ﻣﻴﺰان اﻧﺒﺎشتگی اﻳﻦ ﻋﻨﺎﺻﺮ در ﺧﺎک اﻧﺪازه ﮔﻴﺮی ﺷﺪ. ﻧﺘﺎﻳﺞ ﻧﺸﺎن داد ﻛﻪ ﻣﻘﺎدﻳﺮ ﻛﺮﺑﻦ آﻟﻲ و ﻧﻴﺘﺮوژن ﻛﻞ ﻻﺷﺒﺮگ در روﻳﺸﮕﺎه ﻣﺮتعی ﺑﺎ ﭘﻮﺷﺶ rh. pallasii ﺑﻴﺸﺘﺮﻳﻦ ﻣﻘﺪار ﺑﻮد. ﺑﻴﺸﺘﺮﻳﻦ ﻣﻴﺰان ﻛﻠﺴﻴﻢ و ﻣﻨﻴﺰﻳﻢ ﻗﺎﺑﻞ ﺟﺬب در ﻻﺷﺒﺮگ روﻳﺸﮕﺎه جنگلی و ﺑﻴﺸﺘﺮﻳﻦ ﻣﻘﺪار ﭘﺘﺎﺳﻴﻢ و ﻓﺴﻔﺮ ﻗﺎﺑﻞ ﺟﺬب )%1/36 و در ﻻﺷﺒﺮگ روﻳﺸﮕﺎه ﻣﺮتعی ﺑﺎ ﭘﻮﺷﺶ st. byzantina ﺑﻮده اﺳﺖ. ﻣﻴﺰان اﻧﺒﺎشتگی ﻛﺮﺑﻦ آﻟﻲ، ﻧﻴﺘﺮوژن ﻛﻞ،ﻛﻠﺴﻴﻢ و ﻣﻨﻴﺰﻳﻢ ﻗﺎﺑﻞ ﺟﺬب )ﺑﻪ ﺗﺮﺗﻴﺐ 1042088، 229408/3، 188396/8 و 7589/2358 ﻛﻴﻠﻮﮔﺮم ﺑﺮ ﻫﻜﺘﺎر( در ﺧﺎک روﻳﺸﮕﺎه جنگلی ﻧﺴﺒﺖ ﺑﻪ روﻳﺸﮕﺎه ﻣﺮتعی ﺑﻴﺸﺘﺮ ﺑﻮده اﺳﺖ و ﺑﻴﺸﺘﺮﻳﻦ ﻣﻴﺰان اﻧﺒﺎشتگی ﻓﺴﻔﺮ و ﭘﺘﺎﺳﻴﻢ ﻗﺎﺑﻞ ﺟﺬب )18920/28 و 300/976 ﻛﻴﻠﻮ ﮔﺮم ﺑﺮ ﻫﻜﺘﺎر( در ﺧﺎک زﻳﺮ ﭘﻮﺷﺶ st. byzantina ﺑﻮد. ﺑﻪ ﻃﻮر ﻛﻠﻲ ﻧﺘﺎﻳﺞ اﻳﻦ ﺗﺤﻘﻴﻖ ﻧﺸﺎن داد ﻛﻪ راﺑﻄﻪ ﮔﻮﻧﻪ ﻫﺎی ﮔﻴﺎهی ﻣﺨﺘﻠﻒ ﺑﺎ ﻣﻴﺰان اﻧﺒﺎشتگی ﻋﻨﺎﺻﺮ ﺧﺎک ﺛﺎﺑﺖ ﻧﺒﻮده و ﺗﺄﺛﻴﺮ ﮔﺬاری ﻣﺜﺒﺖ ﮔﻮﻧﻪ ﺑﻠﻮط ﺑﺮ ذﺧﻴﺮه ﻋﻨﺎﺻﺮ ﻏﺬایی ﺧﺎک ﻣﻲ ﺗﻮاﻧﺪ ﻧﺎﺷﻲ از ﻛﻤﻴﺖ و ﻛﻴﻔﻴﺖ ﺑﻬﺘﺮ ﻻﺷﺒﺮگ ﻫﺎی ﺗﻮﻟﻴﺪ ﺷﺪه اﻳﻦ ﮔﻮﻧﻪ ﻧﺴﺒﺖ ﺑﻪ دﻳﮕﺮ ﮔﻮﻧﻪ ﻫﺎی ﻣﻮرد ﺑﺮرسی در اﻳﻦ ﺗﺤﻘﻴﻖ ﺑﺎﺷﺪ.

the effects of forest and rangelands covers on accumulation of soil nutrient elements in kojour region

two habitats of rangelands that are dominated by stachys byzantina and rhamnus pallasii and a forest area is dominated by oak (quercus castaneifolia( were selected. in the plots, 36 litter and soil (0-20cm depth) samples were collected and conveyed to laboratory for measuring of the amounts of c, n, ca, mg, k and p elements in the litter and calculation of theirs storage in soil. the results showed that the amount of organic c and n of the litter (84.52 and 2.97%) were highest in rangelands of rh. pallasii. whereas the greater amounts of ca and mg (0.77 and 294.4%) found in forest litter, and also the higher values of k and p (0.31 and 149.0%) were observed in st. byzantina rangelands. the storages of organic c, n, ca and mg (1042088, 29298.3, 188396.88 and 7589.258 kg/ha, respectively) were increased in forest soils, but the st. byzantina rangeland cover improved the accumulation of p and k (18920.28 and 300.97 kg ha-1). in general, the findings of this research showed that the relationship between different plant species and the amount of accumulation of soil elements is not constant, and the positive effect of oak species on soil nutrient storage could be due to the quantity and quality of litter produced by this species compared to other species studied in this study.