تغییرات مکانی مقاومت کششی ریشه سرخ‌بید (Salix elburensis) در حاشیه رودخانه کارون (مطالعه موردی: دشت سوسن)

نوع مقاله : علمی- پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، گروه جنگل‌داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

2 استاد، گروه جنگل‌داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

3 دانشیار، گروه جنگل‌داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

4 استادیار، دانشکده منابع طبیعی، دانشگاه تربیت‌مدرس، نور، ایران

5 دانشجوی دکتری، گروه جنگل داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

چکیده

پوشش­‌های گیاهی حاشیه رودخانه­‌ها با داشتن اثرات هیدرولوژیکی و مکانیکی مختلف می‌توانند عامل مهمی در بهبود ویژگی‌های پایداری خاک به­‌شمار آیند. یکی از مهم‌­ترین مشخصه‌های گیاه که بر پایداری و کنترل فرسایش تأثیرگذار است، مقاومت کششی ریشه گیاهان می‌باشد. هدف از این پژوهش، بررسی تغییرات مکانی مقاومت کششی ریشه درختان سرخ­‌بید (Salix elburensis) در فاصله­‌های مختلف از تنه و عمق­‌های مختلف خاک در بخشی از حاشیه رودخانه کارون (دشت سوسن) بود. پنج پایه برای نمونه­‌برداری سیستم ریشه به‌صورت کاملاً تصادفی انتخاب و از روش نمونه­‌گیری با سیلندر از هسته­‌های خاک استفاده شد. نمونه­‌گیری در سه عمق مختلف، در سه فاصله افقی و در چهار سمت درخت انجام شد. درنهایت، 97 آزمایش کشش موفق بر روی نمونه‌های ریشه‌ انجام شد. روابط بین نیروی کششی- قطر و مقاومت کششی- قطر با استفاده از مدل خطی و تعمیم‌یافته و آزمون والد- مربع کای مقایسه شد. بر اساس نتایج، در عمق‌های صفر تا 10، 20-10 و 30-20 سانتی­‌متری، میانگین مقاومت کششی به‌ترتیب 57/91، 46/96 و 46/27 مگاپاسکال بود. همچنین، در فاصله‌های 0/5، 0/75 و یک متری، میانگین مقاومت کششی به‌ترتیب 29/21، 76/81 و 28/75 مگاپاسکال برآورد شد. قطر ریشه و نیروی کششی از رابطه توانی مثبت و نمایی پیروی کرده، ولی بین قطر ریشه و مقاومت کششی رابطه توانی منفی مشاهده شد. نتایج آزمون والد- مربع کای نشان داد که تفاوت معنی­‌داری بین مقاومت کششی در سه عمق­ خاک و سه فاصله­ افقی وجود نداشت، اما قطر ریشه به‌عنوان عامل کوواریت تأثیر معنی­داری بر مقاومت کششی داشت.

کلیدواژه‌ها

عنوان مقاله [English]

Assessing spatial changes of roots tensile strength of Salix purpurea L. in riparian zone of Karun (Case study: Susan plain in Khuzestan province)

نویسندگان [English]

  • Soghra Keybondori 1
  • Baris Majnounian 2
  • Ehsan Abdi 3
  • Hamed Yousefzadeh 4
  • Azadeh Deljouei 5
1 M.Sc. Student, Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
2 Prof., Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
3 Associate Prof., Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
4 Assistant Prof., Department of Forestry, Faculty of Natural Resources, University of Tarbiat Modares, Noor, Iran
5 Ph.D. Student, Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
چکیده [English]

Vegetation in riparian areas, including trees with various hydrological and mechanical effects has an essential role in soil reinforcement. This is accomplished by increasing soil shear strength and inhibiting the higher layer of soil into the lower layers and reducing erosion by roots. The aim of this study was to evaluate the tensile strength changes of Salix purpurea L. trees in different trunk distances and soil depths. Therefore, five trees were randomly selected for root system sampling, which was done by using the soil core technique. Sampling was taken in three different depths, tree horizontal distances and in four directions of the trees. Finally, 97 successful tensile tests were performed on root samples. The relations between tensile force- diameter and tensile strength-diameter were analyzed and compered. The results showed the average of tensile strength of 57.91, 46.96 and 46.27 Mpa for depths 0-10, 10-20 and 20-30 cm, respectively. Furthermore, the average of tensile strength was 29.18, 76.81 and 28.78 Mpa for 0.5, 0.75 and 1 m distances, respectively. Root diameter and tensile force fallowed positive power and exponential trends. However, the association between root diameter and tensile strength followed a negative power trend. Results of Wald test showed no significant difference between tensile strength of three soil depths and three horizontal distances, though root diameter as a covariate parameter with a significant effect on tensile strength.

کلیدواژه‌ها [English]

  • Bioengineering
  • reinforcement
  • soil core sampling
  • tensile force

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