ارزیابی تاثیر پایـه هـای گـونه Pteropyrum aucheri بر مواد آلی ذره ای و پراکنش خاکدانه ها در مراتع خانقاه سرخ ارومیه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار دانشکده منابع طبیعی دانشگاه ارومیه

2 دانش آموخته کارشناسی ارشد مرتعداری دانشکده منابع طبیعی دانشگاه تربیت مدرس

3 استادیار دانشکده منابع طبیعی دانشگاه تربیت مدرس

چکیده

به منظور ارزیابی تاثیر گونه Pteropyrum aucheri   بر اجزاء ماده آلی خاک و پراکنش خاکدانه­ها، به عنوان شاخص حساس نسبت به تغییرات مدیریتی مرتع، نمونه­های خاک از دو مکان معرف تیپ­ گیاهی Pteropyrum aucheri - Astragalus microcephalus با خصوصیات فیزیکی تقریبا مشابه(شیب، جهت، ارتفاع) و غالبیت گونه Pteropyrum aucheri  ، اما متفاوت از نظر گونه­های همراه در ترکیب گیاهی، در مراتع خانقاه سرخ ارومیه مطالعه شد. برای این منظور در هر مکان، با توجه به پراکنش پوشش گیاهی و خصوصیات فیزیکی مراتع مورد بررسی، 6 عدد ترانسکت 100 متری که 4 عدد از آنها موازی با جهت شیب و 2 عدد از آنها عمود بر جهت شیب بودند،‌ بطور سیستماتیک در تیپ­های گیاهی مستقر و نمونه­های خاک با سه تکرار از لایه سطحی (عمق 15-0 سانتیمتر) و پائینی (30- 15 سانتیمتر) پروفیل­های حفر شده در ابتدا، وسط و انتهای ترانسکت­ها برداشت شد. سپس مقادیر شاخص­های خاک شامل؛‌ کربن، مواد آلی ذره­ای کربن (POM-C)،‌ ازت، مواد آلی ذره­ای نیتروژن (POM-N)، خاکدانه­های درشت و خاکدانه­های ریز و کربن موجود در خاکدانه­ها اندازه­گیری گردید. اطلاعات مربوط به پوشش گیاهی مکان­های انتخابی نیز در داخل پلات­های یک متر مربعی (60 عدد پلات) که با فواصل 10 متر از همدیگر در امتداد ترانسکت­ها مستقر شده بودند، ثبت و بر مبنای آنها، شاخص­های عددی تنوع و یکنواختی در مکان­های مذکور محاسبه شد. نتایج آنالیز واریانس نمونه­های خاک، نشان داد که بین مقادیر شاخص­ها در عمق­های مختلف خاک مکان­های مورد بررسی، اختلاف معنی­دار وجود دارد و در تمامی موارد بجز مقدار خاک دانه­های ریز، مقادیر شاخص­ها (شامل؛ مقدار کربن، نیتروژن، کربن آلی ذره­ای، نیتروژن آلی ذره­ای، درصد خاکدانه­های درشت، درصد کربن موجود در خاکدانه­های درشت و ریز)، در افق سطحی خاک بیشتر از افق پائینی می­باشد. ضمن اینکه مقادیر هر یک از شاخص­ها در مکان مرتعی شماره 1 به لحاظ تنوع گونه­ای بهتر، بیشتر از مکان مرتعی شماره 2 است. این امر بیانگر این است که اجزاء فیزیکی ماده آلی خاک، تغییرات بوجود آمده حاصل از تاثیر گونه Pteropyrum aucheri  را بر کمیت و کیفیت ماده آلی خاک می‌توانند توجیه کنند. ضمن اینکه نتایج مذکور، ظاهر شدن سریع تاثیر تغییرات مدیریتی در اجزاء نیتروژن و کربن ناپایدار را تایید و همچنین حساسیت پذیری مواد آلی ذره­ای خاک را در واکنش به تغییرات مدیریتی مرتع، اثبات کرد. بنابراین می­توان چنین نتیجه گیری کرد که داشتن اطلاعات پیرامون تغییرات مواد آلی ذره­ای و پراکنش خاکدانه­ها، به منظور مدیریت اکوسیستم­های مرتعی سودمند خواهد بود. 

کلیدواژه‌ها


عنوان مقاله [English]

Assessing the Impact of Pteropyrum Aucheri Species on Particulate Organic Matter and Soil Aggregate Dispersion

نویسندگان [English]

  • Javad Motamedi 1
  • Behnam Bahrami 2
  • Reza Erfanzadeh 3
1 Assistant Professor, Faculty of Natural Resources, Urmia University
2 Graduate Student of Range management, Faculty of Natural Resources, Tarbiat Modares University
3 Associate Professor, Faculty of Natural Resources, Tarbiat Modares University
چکیده [English]

In order to assess the impact of Pteropyrum aucheri on soil organic matter components and the soil aggregate dispersion, as the sensitive index of grassland management changes, soil samples were taken from two locations in area rangelands representing the Pteropyrum aucheri - Astragalus microcephalus vegetation types with similar physical properties (Slope, Aspect, Elevation) and dominance of Pteropyrum aucheri species but with different coexisting species in the species composition. For this purpose, in each location regarding the vegetation distribution and physical characteristics of the ranges under study, 6 transects that were 100 meters long were placed systematically in vegetation types while 4 of them were parallel to slope and 2 of them were perpendicular to the slope. Soil samples were taken with three replicates from surface horizons (depth of 0-15 cm) and lower horizons (depth of 15-30 cm) of drilled profiles at the beginning, middle, and end of transects. Then, the values of soil characteristics, including carbon, particulate organic matter carbon (POM-C), nitrogen, particulate organic matter nitrogen (POM-N), micro-aggregate, macro-aggregate, and the Carbon in the aggregate, were measured. The information related to the vegetation of selected areas inside one-squared meter plots (60 plots) with 10 meters long intervals deployed along the transects were recorded, and based on this information, numerical indices of diversity and evenness in the selected areas were calculated. The results of the ANOVA test of soil samples revealed that there is a significant difference between index values at different soil horizons of studied areas, and in all of the cases, excluding the amount of the micro-aggregate, the indices values (Including; C, N, POM-C, POM-N, Macro-aggregate, C-associated with macro and micro- aggregates) are more in surface horizons than the lower ones. Moreover, the values of each of the indices in number 1 grassland location was more than number 2 location since number 1 location has a better species diversity. This suggests that the physical components of soil organic matter justifies the changes resulted from the Pteropyrum aucheri species impact on the quantity and quality of soil organic matter. Furthermore, the above results confirm the hypothesis suggesting the rapid emergence of management changes in the components of nitrogen and unstable carbon. The results also prove the sensitivity of soil particulate organic matter to the pasture management changes. Therefore, having information regarding the changes of particulate organic matter and soil aggregate dispersion would be beneficial for the pasture ecosystem management. 

کلیدواژه‌ها [English]

  • vegetation distribution
  • Pteropyrum aucheri
  • soil aggregate
  • soil particulate organic matter
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