اثر فرسایش آبی بر تنوع زیستی خاک در اکوسیستم‌های خشک

نوع مقاله : علمی -پژوهشی

نویسنده

استادیار گروه جغرافیا، دانشکده ادبیات و علوم انسانی، دانشگاه فردوسی مشهد

چکیده

فرسایش خاک به عنوان یک فرایند ژئومورفیک علاوه بر تلفات خاک، اثرات شدیدی بر تنوع زیستی خاک دارد. دینامیک تنوع زیستی خاک می­تواند شاخصی برای ارزیابی میزان سازگاری اکوسیستم­ها در برابر تغییرات محیطی باشد. از آنجا که اکوسیستم­های خشک و نیمه­خشک نقش مهمی در انتشار کربن به اتمسفر دارند، عملکرد فرآیندهای فرسایشی می­تواند شرایطی را برای توقیف کربن و متعاقباً اثرات مثبت در راستای افزایش سازگاری این اکوسیستم­ها در برابر تغییرات محیطی فراهم آورد. در این مطالعه با هدف بررسی اثرات فرسایش آبی بر تنوع میکروبی خاک، نمونه­های خاک از بخش­های مختلف سه مخروط افکنه برای اندازه­گیری فعالیت­های آنزیمی، کربن زیست توده میکروبی، کربن آلی، کربن آلی ناپایدار (محلول)، توزیع اندازه ذرات خاک و رطوبت خاک برداشت شد. نتایج نشان داده است، میزان کربن آلی و نیتروژن کل در سایت­های رسوبی به­طور معنی­داری کمتر از سایت­های فرسایشی بوده است. در حالی که بیشترین میزان کربن آلی محلول و کربن زیست توده میکروبی در سایت­های رسوبی دیده شده است. همچنین در مقایسه با سایت­های فرسایشی، فعالیت آنزیم­ کاتالاز بیشترین مقدار را در نمونه­های مربوط به سایت­های رسوبی نشان داده است. براساس این یافته­ها، معدنی شدن و تجزیه کربن آلی در سایت­های فرسایشی و رسوبی به شدت مرتبط با تغییر در ویژگی­های بیوژئوشیمیایی خاک است. به طوری­که از مجموعه ویژگی­های زیستی خاک، اثرگذاری کیفیت کرین در افزایش ارتجاع پذیری اکوسیستم­ها بسیار مهم‌تر از کمیت کرین می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Impact of water erosion on soil biological diversity in arid ecosystems

نویسنده [English]

  • neda mohseni
Assistant Professor, Department of Geography, Faculty of Letters and Humanities, Ferdowsi University of Mashhad
چکیده [English]

Soil erosion is a geomorphic process that can increase soil losses and affect the dynamics of soil biological diversity. Soil biological diversity can considers as an indicator for assessing adaptation rate of arid ecosystems against environmental changes. This study evaluates variations in soil microbial diversity and physiochemical properties in erosional landscapes. Since, arid and semi-arid ecosystems have a critical role in flux of carbon dioxide to atmosphere; many erosional landforms belonging to these ecosystems can occur a condition for sequestrating carbon and subsequently positive impacts for increasing resilience level against environmental harshness. One of the common landforms in arid landscapes is alluvial fan. Soil samples were collected from different topographic positions of the three alluvial fans for measuring enzyme activities, particle size distribution, soil water, soil microbial activity, and soil organic carbon. The findings showed that different positions exhibit different conditions in terms of carbon mineralization and sequestration causing the heterogeneous dynamics of soil biological properties.

کلیدواژه‌ها [English]

  • Geomorphic process
  • Water erosion
  • Biological diversity
  • Enzyme activities
  • Arid ecosystem
  1. -Berhe, A.A. and Kleber, M., 2013. Erosion, deposition, and the persistence of soil organic matter: mechanistic considerations and problems with terminology: Earth Surface Processes and Landforms, v. 38, p. 908-912.
  2. -Blake, G.R. and Hartge, K.H., 1986. Bulk density. In: Klute, A. (Ed.), Methods of Soil Analysis, Part 1, Physical and Mineralogical Methods, American Society of Agronomy and Soil Science, Madison, WI, p. 363–375.
  3. -Bremner, J.M., 1996. Nitrogen-total. In: Sparks, D.L. (Ed.), Methods of Soil Analysis,
  4. Part 3, Chemical Methods. SSSA-ASA, Madison, WI, p. 1085e1121.
  5. -Caldwell, B.A., 2005. Enzyme activities as a component of soil biodiversity: a review: Pedobiologia, v. 49, p. 637-644.
  6. -Chance, B. and Maehly, A.C., 1995. Assay of catalase and peroxidase, In: Colowick, S. P., and N. D. Kaplan (eds.), Methods in Enzymology, Academic Press, New York, v. 2, p. 764–791.
  7. -Chaplot, V. and Poesen, J., 2012. Sediment, soil organic carbon and runoff delivery at various spatial scales: Catena, v. 88, p. 46-56.
  8. -Dungait, J.A., Ghee, C., Rowan, J.S., McKenzie, B.M., Hawes, C., Dixon, E.R., Paterson, E. and Hopkins, D.W., 2013. Microbial responses to the erosional redistribution of soil organic carbon in arable fields: Soil Biology and Biochemistry, v. 60, p. 195-201.
  9. -Hou, S., Xin, M., Wang, L., Jiang, H., Li, N. and Wang, Z., 2014. The effects of erosion on the microbial populations and enzyme activity in black soil of northeastern China: Acta Ecologica Sinica, v. 34, p. 295-301.
  10. -Huang, J., Li, Z., Zeng, G., Zhang, J., Li, J., Nie, X., Ma, W. and Zhang, X., 2013. Microbial responses to simulated water erosion in relation to organic carbon dynamics on a hilly cropland in subtropical China: Ecological engineering, v. 60, p. 67-75.
  11. -Jacinthe, P.A. and Lal, R., 2001. A mass balance approach to assess carbon dioxide evolution during erosional events: Land Degradation & Development, v. 12, p. 329-339.
  12. -Kemmitt, S.J., Lanyon, C.V., Waite, I.S., Wen, Q., Addiscott, T.M., Bird, N.R., O’donnell, A.G. and Brookes, P.C., 2008. Mineralization of native soil organic matter is not regulated by the size, activity or composition of the soil microbial biomass—a new perspective: Soil Biology and Biochemistry, v. 40, p. 61-73.
  13. -Kirkels, F.M.S.A., Cammeraat, L.H. and Kuhn, N.J., 2014. The fate of soil organic carbon upon erosion, transport and deposition in agricultural landscapes—A review of different concepts: Geomorphology, v. 226, p. 94-105.
  14. -Lal, R., 2003. Soil erosion and the global carbon budget: Environment international, v. 29, p.437-450.
  15. -Lal, R., 2005. Soil erosion and carbon dynamics, Soil & Tillage Research, v. 81, p. 137–142.
  16. -Li, Z., Xiao, H., Tang, Z., Huang, J., Nie, X., Huang, B., Ma, W., Lu, Y. and Zeng, G., 2015. Microbial responses to erosion-induced soil physico-chemical property changes in the hilly red soil region of southern China: European Journal of Soil Biology, v. 71, p. 37-44.
  17. -Mabuhay, J.A., Nakagoshi, N. and Isagi, Y., 2004. Influence of erosion on soil microbial biomass, abundance and community diversity: Land Degradation & Development, v. 15, p. 183-195.
  18. -Makoi, J.H. and Ndakidemi, P.A., 2008. Selected soil enzymes: examples of their potential roles in the ecosystem: African Journal of Biotechnology, v. 7, p. 181-191.
  19. -Mchunu, C.N., Lorentz, S., VandenBygaart, A.J., Gregorich, E.G. and Helgason, B.L., 2015. Cropland C erosion and burial: Is buried soil organic matter biodegradable? Geoderma, v. 239, p. 240-249.
  20. -Novara, A., Keesstra, S., Cerdà, A., Pereira, P. and Gristina, L., 2016. Understanding the role of soil erosion on CO2-C loss using 13C isotopic signatures in abandoned Mediterranean agricultural land: Science of the Total Environment, v. 550, p. 330-336.
  21. -Olson, K.R., Al-Kaisi, M., Lal, R. and Cihacek, L., 2016. Impact of soil erosion on soil organic carbon stocks: Journal of Soil and Water Conservation, v. 71, p. 61A-67A.
  22. -Park, J.H., Meusburger, K., Jang, I., Kang, H. and Alewell, C., 2014. Erosion-induced changes in soil biogeochemical and microbiological properties in Swiss Alpine grasslands: Soil Biology and Biochemistry, v. 69, p. 382-392.
  23. -Polyakov, V.O. and Lal, R., 2008. Soil organic matter and CO2 emission as affected by water erosion on field runoff plots: Geoderma, v. 143, p. 216-222.
  24. -Rowell, DL., 1994. SoilScience: methods & applications.,(Longman Scientific & Technical: Harlow, UK). Soil science: Methods and applications, Longman Scientific and Technical, Harlow, UK.
  25. -Shi, W., 2011. Agricultural and ecological significance of soil enzymes: soil carbon sequestration and nutrient cycling, In Soil enzymology, p. 43-60.
  26. -Smith, S.V., Sleezer, R.O., Renwick, W.H. and Buddemeier, R.W., 2005. Fates of eroded soil organic carbon: Mississippi basin case study: Ecological Applications, v. 15, p. 1929-1940.
  27. -Stallard, R.F., 1998. Terrestrial sedimentation and the carbon cycle: coupling weathering and erosion to carbon burial: Global Biogeochemical Cycles, v. 12, p. 231-257.
  28. -Stott, D.E., Andrews, S.S., Liebig, M.A., Wienhold, B.J. and Karlen, D.L., 2010. Evaluation of β-glucosidase activity as a soil quality indicator for the soil management assessment framework: Soil Science Society of America Journal, v. 74, p. 107-119.
  29. -Trivedi, P., Anderson, I.C. and Singh, B.K., 2013. Microbial modulators of soil carbon storage: integrating genomic and metabolic knowledge for global prediction: Trends in microbiology, v. 21, p. 641-651.
  30. -Van Oost, K., Beuselinck, L., Hairsine, P.B. and Govers, G., 2004. Spatial evaluation of a multi‐class sediment transport and deposition model, Earth Surface Processes and Landforms: The Journal of the British Geomorphological Research Group, v. 29, p. 1027-1044.
  31. -Vance, E.D., Brookes, P.C. and Jenkinson, D.S., 1987. An extraction method for measuring soil microbial biomass C: Soil biology and Biochemistry, v. 19, p. 703-707.
  32. -Walkley, A.J. and Black, I.A., 1934. Estimation of soil organic carbon by the chromic acid titration method: Soil Sci, v. 37, p. 29-38.
  33. -Walling, D.E. and Moorehead, P.W., 1989. The particle size characteristics of fluvial suspended sediment: an overview: Hydrobiologia, v. 176, p. 125–149.
  34. -Wang, X., Cammeraat, E.L., Cerli, C. and Kalbitz, K., 2014. Soil aggregation and the stabilization of organic carbon as affected by erosion and deposition: Soil Biology and Biochemistry, v. 72, p. 55-65.
  35. -Wei, S., Zhang, X., McLaughlin, N.B., Chen, X., Jia, S. and Liang, A., 2017. Impact of soil water erosion processes on catchment export of soil aggregates and associated SOC: Geoderma, v. 294, p. 63-69.
  36. -Wei, S., Zhang, X., McLaughlin, N.B., Yang, X., Liang, A., Jia, S. and Chen, X., 2016. Effect of breakdown and dispersion of soil aggregates by erosion on soil CO2 emission: Geoderma, v. 264, p. 238-243.