پديد آورندگان :
محمودآبادي, مجيد دانشگاه شهيد باهنر كرمان - دانشكده كشاورزي - گروه علوم و مهندسي خاك , زماني, سميرا دانشگاه شهيد باهنر كرمان - دانشكده كشاورزي - گروه علوم و مهندسي خاك , يزدان پناه, نجمه دانشگاه آزاد اسلامي كرمان - گروه مهندسي آب
كليدواژه :
دﯾﻨﺎﻣﯿﮏ ﮐﺮﺑﻦ آﻟﯽ , ﺳﺮﻋﺖ ﺑﺎد و ﺷﺪت ﺑﺎران , ﺧﺮدﺷﺪن ﺧﺎﮐﺪاﻧﻪ , ﻋﻤﻖ ﺟﺮﯾﺎن
چكيده فارسي :
ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري، ﯾﮑﯽ از اﻧﻮاع ﻣﻬﻢ ﻓﺮﺳﺎﯾﺶ در اراﺿﯽ ﮐﺸﺎورزي اﺳﺖ ﮐﻪ ﺑﺎﻋﺚ ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ از ﺳﻄﺢ ﺧﺎك ﻣﯽ ﺷﻮد. اﯾﻦ در ﺣﺎﻟﯽ اﺳﺖ ﮐﻪ ﮐﻤﺒﻮد ﮐﺮﺑﻦ آﻟﯽ ﺧﺎك در ﺑﯿﺸﺘﺮ ﻣﻨﺎﻃﻖ ﺧﺸﮏ و ﻧﯿﻤﻪ ﺧﺸﮏ اﯾﺮان، ﯾﮑﯽ از ﭼﺎﻟﺶ ﻫﺎي ﭘﯿﺶ روي ﺗﻮﻟﯿﺪ ﻣﺤﺼﻮﻻت ﮐﺸﺎورزي اﺳﺖ. در اﯾﻦ ﻣﻨﺎﻃﻖ، ﺑﺎرش ﺑﺎران ﻣﻤﮑﻦ اﺳﺖ ﺑﺎ وزش ﺑﺎدﻫﺎي ﻓﺮﺳﺎﯾﻨﺪه ﻫﻤﺮاه ﺑﺎﺷﺪ ﮐﻪ ﻣﻘﺎدﯾﺮ زﯾﺎدي از ﺧﺎك و ﮐﺮﺑﻦ آﻟﯽ را از ﺑﯿﻦ ﻣﯽ ﺑﺮد. ﻟﺬا، ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ ﻧﻘﺶ ﻋﻮاﻣﻞ ﻓﺮﺳﺎﯾﻨﺪه ﺑﺎد و ﺑﺎران ﺑﺮ ﻫﺪررﻓﺖ ﺧﺎك و ﮐﺮﺑﻦ آﻟﯽ و ﻧﯿﺰ ﻏﻨﯽ ﺷﺪﮔﯽ رﺳﻮب ﻃﯽ رﺧﺪاد ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري ﺑﺮﻧﺎﻣﻪ رﯾﺰي ﺷﺪه اﺳﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر، ﺑﺎ اﺳﺘﻔﺎده از ﺳﺎﻣﺎﻧﻪ ﺷﺒﯿﻪ ﺳﺎز ﻫﻤﺰﻣﺎن ﺑﺎد و ﺑﺎران، ﺗﺮﮐﯿﺒﯽ از ﺳﻪ ﺷﺪت ﺑﺎران )40 ،20 و 60 ﻣﯿﻠﯽ ﻣﺘﺮ ﺑﺮ ﺳﺎﻋﺖ( و ﭼﻬﺎر ﺳﺮﻋﺖ ﺑﺎد )ﺻﻔﺮ، ﺷﺶ، ﻧﻪ و 12 ﻣﺘﺮ ﺑﺮ ﺛﺎﻧﯿﻪ( روي ﺳﻪ ﺧﺎك ﺑﺎ ﺑﺎﻓﺖ ﻣﺨﺘﻠﻒ )ﺷﻨﯽ، ﻟﻮم ﺷﻨﯽ و ﻟﻮم(، ﻫﺮ ﯾﮏ در ﺳﻪ ﺗﮑﺮار اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ ﺑﯿﻦ ﺧﺎك ﻫﺎﯾﯽ ﺑﺎ ﺑﺎﻓﺖ ﻣﺨﺘﻠﻒ از 0/04 و 4/04 ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﻣﺘﺮ در ﺛﺎﻧﯿﻪ ﻣﺘﻐﯿﺮ ﺑﻮده اﺳﺖ. ﻧﺘﺎﯾﺞ دﻻﻟﺖ ﺑﺮ اﺛﺮ ﻣﺘﻘﺎﺑﻞ ﻫﻢ اﻓﺰاي دو ﻋﺎﻣﻞ ﻓﺮﺳﺎﯾﻨﺪه ﺑﺎد و ﺑﺎران ﺑﺮ ﻫﺪررﻓﺖ ﺧﺎك و ﮐﺮﺑﻦ آﻟﯽ داﺷﺖ. ﻫﻤﭽﻨﯿﻦ، ﺑﺮاي ﺳﺮﻋﺖ ﺑﺎد، ﯾﮏ ﺣﺪ آﺳﺘﺎﻧﻪ )ﻧﻪ ﻣﺘﺮ ﺑﺮ ﺛﺎﻧﯿﻪ( ﻣﺸﺎﻫﺪه ﺷﺪ ﮐﻪ در ﺳﺮﻋﺖ ﺑﯿﺸﺘﺮ از اﯾﻦ ﺣﺪ، ﻫﺪررﻓﺖ ﺧﺎك و ﮐﺮﺑﻦ آﻟﯽ ﺑﺎ ﺷﯿﺐ ﺗﻨﺪﺗﺮي اﻓﺰاﯾﺶ ﭘﯿﺪا ﮐﺮد. از ﻃﺮﻓﯽ، ﺑﺎ اﻓﺰاﯾﺶ ﻫﺪررﻓﺖ ﺧﺎك، ﻣﯿﺰان ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ از ﻫﺮ ﺧﺎك ﻧﯿﺰ ﺑﻪ ﺻﻮرت ﺧﻄﯽ اﻓﺰاﯾﺶ ﭘﯿﺪا ﮐﺮد. ﺳﻬﻢ ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ از ﻣﯿﺰان ﮐﻞ ﻫﺪررﻓﺖ ﺧﺎك ﺑﺮاي ﺧﺎك ﻫﺎي ﺷﻨﯽ، ﻟﻮم ﺷﻨﯽ و ﻟﻮم ﺑﻪ ﺗﺮﺗﯿﺐ 0/17 ،0/36 و 2/19 درﺻﺪ ﺗﻌﯿﯿﻦ ﺷﺪ. ﻫﻤﭽﻨﯿﻦ، ﻧﺴﺒﺖ ﻏﻨﯽ ﺷﺪﮔﯽ ﮐﺮﺑﻦ آﻟﯽ در رﺳﻮب اﯾﻦ ﺧﺎك ﻫﺎ، ﺑﻪ ﺗﺮﺗﯿﺐ 1/0 ،8/0 و 2/1 ﺑﻮد. ﺑﺮ اﺳﺎس ﯾﺎﻓﺘﻪ ﻫﺎي اﯾﻦ ﭘﮋوﻫﺶ، ﮐﺎﻫﺶ ﺳﺮﻋﺖ ﺑﺎد در اراﺿﯽ ﮐﺸﺎورزي ﺑﻪ وﯾﮋه ﻣﻨﺎﻃﻖ ﺑﺎدﺧﯿﺰ، ﺑﺮاي ﮐﻨﺘﺮل ﻫﺪررﻓﺖ ﮐﺮﺑﻦ آﻟﯽ در اﺛﺮ ﻓﺮﺳﺎﯾﺶ ﺑﯿﻦ ﺷﯿﺎري از ﺧﺎك ﺳﻄﺤﯽ ﭘﯿﺸﻨﻬﺎد ﻣﯽ ﺷﻮد
چكيده لاتين :
Interrill erosion is one of the most important types of erosion in agricultural lands, causing organic carbon (OC) loss from the soil surface. However, soil OC deficiency is a challenge facing agricultural production in most arid and semi-arid regions of Iran. In these regions, rainfall may be associated with high-speed winds that may remove large amounts of soil and OC. Therefore, the present study was carried out to investigate the role of wind and rain as erosive factors on the soil and OC losses and sediment enrichment during erosion events in some contrasting soils. For this purpose, using a simultaneous wind and rain simulator, combinations of three rain intensities (20, 40 and 60 mm h-1) and four wind speeds (0, 6, 9 and 12 m s-1) were introduced on three soils (sandy, sandy loam, and loam), each at three replicates. The results showed that the OC loss from the soils changed from 0.04 to 4.04 mg m-1 s-1. Synergistic interaction between rain and wind on OC loss was detected. In addition, a threshold limit (9 m s-1) was observed for wind velocity, above which soil and OC losses increased sharply. On the other hand, with increasing soil loss, the OC loss from each soil increased linearly. The contribution of OC loss in the total soil loss for sandy, sandy loam and loam soils was 0.36, 0.17 and 2.19%, respectively. Moreover, the enrichment ratio of OC in the sediments of soils was 8.2, 1.01 and 12.2, respectively. Based on the findings of this study, the wind speed reduction is recommended in agricultural lands, especially in windy areas to control the losses of OC due to interrill erosion.
