كليدواژه :
حجم آبكند , طول آبكند , كاربري زمين , شخم , مساحت زهكش
چكيده فارسي :
ﻓﺮﺳﺎﯾﺶ آﺑﮑﻨﺪي ﯾﮑﯽ از ﻣﻬﻢﺗﺮﯾﻦ اﻧﻮاع ﻓﺮﺳﺎﯾﺶ آﺑﯽ اﺳﺖ ﮐﻪ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺗﻮﻟﯿﺪ رﺳﻮب و ﺗﺨﺮﯾﺐ ﺷﺪﯾﺪ ﺧﺎك، ﻣﻄﺎﻟﻌﻪ آن
اﻫﻤﯿﺖ وﯾﮋهاي دارد. اﻃﻼﻋﺎت اﻧﺪﮐﯽ در ﻣﻮرد ﮔﺴﺘﺮش ﻓﺮﺳﺎﯾﺶ آﺑﮑﻨﺪي در ﻣﻨﺎﻃﻖ ﺗﺤﺖ ﮐﺸﺎورزي دﯾﻢ وﺟﻮد دارد. ﻣﻄﺎﻟﻌﻪ
ﺣﺎﺿﺮ ﺑﻪﻣﻨﻈﻮر ﺑﺮرﺳﯽ رواﺑﻂ ﺑﯿﻦ وﯾﮋﮔﯽﻫﺎي ﻣﻮرﻓﻮﻣﺘﺮي آﺑﮑﻨﺪ و ﺗﺄﺛﯿﺮ ﺑﺮﺧﯽ ﻋﻮاﻣﻞ زﻣﯿﻨﯽ )ﻃﻮل، ﺷﯿﺐ، ﻣﺴﺎﺣﺖ زﻫﮑﺶ،
ﮐﺎرﺑﺮي زﻣﯿﻦ و ﺟﻬﺖ ﺷﺨﻢ( ﺑﺮ ﮔﺴﺘﺮش ﻓﺮﺳﺎﯾﺶ آﺑﮑﻨﺪي ﺑﻪﻣﻨﻈﻮر ﺑﺮرﺳﯽ راهﮐﺎرﻫﺎي ﺣﻔﺎﻇﺘﯽ در ﺟﻬﺖ ﮐﺎﻫﺶ ﻫﺪررﻓﺖ
ﺧﺎك در ﭘﻬﻨﻪاي ﮐﺸﺎورزي ﺑﻪ وﺳﻌﺖ 900 ﮐﯿﻠﻮﻣﺘﺮ ﻣﺮﺑﻊ در ﺟﻨﻮب اﺳﺘﺎن آذرﺑﺎﯾﺠﺎن ﺷﺮﻗﯽ اﻧﺠﺎم ﮔﺮﻓﺖ. در اﯾﻦ راﺳﺘﺎ 223
آﺑﮑﻨﺪ در ﻣﻨﻄﻘﻪ ﺷﻨﺎﺳﺎﯾﯽ و وﯾﮋﮔﯽﻫﺎي ﻣﻮرﻓﻮﻣﺘﺮي ﺷﺎﻣﻞ ﻃﻮل، ﻋﺮض، ﻋﻤﻖ، اﺧﺘﻼف ارﺗﻔﺎع دو ﺳﺮ آﺑﮑﻨﺪ، ﻣﺴﺎﺣﺖ ﻣﻘﻄﻊ
و ﺣﺠﻢ در ﮐﻨﺎر ﻋﻮاﻣﻞ زﻣﯿﻨﯽ ﺷﺎﻣﻞ درﺟﻪ ﺷﯿﺐ، درﺟﻪ ﺷﯿﺐ زﻣﯿﻦ ﺑﺎﻻدﺳﺖ آﺑﮑﻨﺪ و ﻃﻮل زﻣﯿﻦ، ﺳﻄﺢ زﻫﮑﺶ و ﻋﻮاﻣﻞ
ﻣﺪﯾﺮﯾﺘﯽ )ﮐﺎرﺑﺮي زﻣﯿﻦ و ﺟﻬﺖ ﺷﺨﻢ( ﺗﻌﯿﯿﻦ ﺷﺪ. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ، آﺑﮑﻨﺪﻫﺎ در ﻋﺮﺻﻪﻫﺎﯾﯽ ﺑﺎ ﻣﺴﺎﺣﺖ ﺣﻮﺿﻪ زﻫﮑﺶ 1/5 ﺗﺎ
45/1 ﻫﮑﺘﺎر ﮔﺴﺘﺮش ﯾﺎﻓﺘﻪ، ﻃﻮل آنﻫﺎ از 52 ﻣﺘﺮ ﺗﺎ 2088 ﻣﺘﺮ و ﺣﺠﻢ آنﻫﺎ از 150 ﺗﺎ 35088 ﻣﺘﺮ ﻣﮑﻌﺐ ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ. ﻫﻤﺒﺴﺘﮕﯽ ﻣﻌﻨﯽدار ﺑﯿﻦ ﺣﺠﻢ آﺑﮑﻨﺪ و ﻃﻮل، ﻋﺮض، ﻋﻤﻖ، ﺷﺎﺧﺺ ﺷﮑﻞ و ﺳﻄﺢ ﻣﻘﻄﻊ آﺑﮑﻨﺪ وﺟﻮد دارد. ﻃﻮل آﺑﮑﻨﺪ ﻣﻬﻢﺗﺮﯾﻦ ﻣﺸﺨﺼﻪ ﻣﻮرﻓﻮﻣﺘﺮي آﺑﮑﻨﺪ ﺑﺮاي ﺑﯿﺎن ﮔﺴﺘﺮش آﺑﮑﻨﺪﻫﺎ در ﻣﻨﻄﻘﻪ اﺳﺖ. ﮔﺴﺘﺮش ﻓﺮﺳﺎﯾﺶ آﺑﮑﻨﺪي ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﻣﺴﺘﻘﯿﻢ اﺧﺘﻼف ارﺗﻔﺎع دو ﺳﺮ آﺑﮑﻨﺪ )51 /r=0(، ﻣﺴﺎﺣﺖ ﻋﺮﺻﻪ زﻫﮑﺶ )r=0/71( و ﻃﻮل داﻣﻨﻪ )78 /r=0( و ﺗﺤﺖ ﺗﺄﺛﯿﺮ
ﻋﮑﺲ ﺷﯿﺐ داﻣﻨﻪ و ﺷﯿﺐ زﻣﯿﻦ ﺑﺎﻻدﺳﺖ ﻗﺮار دارد. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﻃﻮل داﻣﻨﻪ ﻣﻬﻢﺗﺮﯾﻦ ﻋﺎﻣﻞ ﻣﺆﺛﺮ ﺑﺮ ﮔﺴﺘﺮش آﺑﮑﻨﺪﻫﺎ
در ﻣﻨﻄﻘﻪ اﺳﺖ. ﺑﻪﻃﻮري ﮐﻪ در داﻣﻨﻪﻫﺎي ﻃﻮﻻﻧﯽ، ﺗﻮﺳﻌﻪ ﻃﻮﻟﯽ آﺑﮑﻨﺪ و در ﻧﺘﯿﺠﻪ ﮔﺴﺘﺮش ﺣﺠﻤﯽ آﺑﮑﻨﺪ ﺑﯿﺶﺗﺮ اﺳﺖ. در
ﭼﻨﯿﻦ داﻣﻨﻪﻫﺎﯾﯽ اﺟﺮاي ﻋﻤﻠﯿﺎت ﺣﻔﺎﻇﺖ ﺧﺎك ﺿﺮوري اﺳﺖ.
چكيده لاتين :
Gully erosion is one of the most important types of water erosion, due to sediment production and severe soil degradation. There is a few information on development of gully erosion in agricultural rainfed areas. This study was carried out to investigate the relationship among gully morphometric characteristics and to find out the effect of land factors (gully length, slope, surface drainage area, land use and plough direction) on gully formation. Also, some conservation strategies for reducing soil losses were studied in a 900 km2 agricultural area in south of Eastern Azarbijan province. For this purpose, 223 gullies were identified in the study area and some characteristics including length, width, depth, elevation difference between the two sides of gully, cross section area and volume, along with land factors consist of slope gradient of land and upland, slope length, surface drainage area, and management factors (land use and plough direction) were determined. Based on the results, gullies have developed in the areas with a drainage surface ranged from 1.5 to 45.1 ha and their length varies from 52 to 2088 m and the volume is between 150 and 35088 m3. Significant correlations are found between gully volume and length, width, depth, shape factor and cross section area. The length is the most important morphometric characteristics to explain gully volume in the lands. Gully development is directly affected by land’s factors including the elevation difference between the two sides of gully (r= 0.51), surface drainage area (r= 0.71), and length (r= 0.78), while it inversely affected by land and upland slope. The gully length is the major factor controlling gully erosion in the area. So that in long slopes, the longitudinal development of the gully and consequently the volumetric expansion of the gully is more. In such areas it is necessary to carry out soil conservation practices.
