تأثیر پوشش لاشبرگ و مازاد مقطوعات بر مقدار رواناب و رسوب در ترانشه های خاکبرداری و خاکریزی جاده های جنگلی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده منابع طبیعی، دانشگاه گیلان، صومعه سرا، ایران.

2 دانشگاه گیلان، دکتری

3 دانشکده منابع طبیعی، دانشگاه گیلان، صومعه سرا، ایران

4 دانش آموخته دکترای جنگلداری، دانشگاه گیلان

چکیده

احداث جاده‌های جنگلی یکی از عوامل ناپایداری دامنه‌های شیبدار است که سبب فرسایش خاک و آثار ناشی از آن می‌شود. هدف این پژوهش، بررسی تأثیر پوشش لاشبرگ و مازاد مقطوعات بر مقدار رواناب و رسوب در ترانشه‌های خاکبرداری و خاکریزی جاده‌های جنگلی در جنگل‌های استان گیلان بود. بدین منظور چهار ترانشۀ خاکبرداری و خاکریزی انتخاب و در هر ترانشه، چهار پلات 2 مترمربعی شامل بدون پوشش (طبقۀ 1)، پوشش 30 درصد (طبقۀ 2)، پوشش 60 درصد (طبقۀ 3) و پوشش 90 درصد (طبقۀ 4) و با شیب ثابت 30 درصد برداشت شد. اندازه‌گیری نمونه‌ها پس از هر بار بارش با شدت تقریبی 80 میلی‌متر در ساعت انجام گرفت. نتایج نشان داد که میانگین رواناب تولیدی در ترانشۀ خاکبرداری در پلات‌های با پوشش صفر (کنترل)، 30، 60 و 90 درصد به‌ترتیب 3/759، 6/748، 6/372 و 0/196 میلی‌لیتر در متر مربع، در ترانشۀ خاکریزی به‌ترتیب 6/216، 6/156، 1/77 و 5/69 میلی‌لیتر در مترمربع و میانگین رسوب در ترانشۀ خاکبرداری در طبقات مختلف به‌ترتیب 08/1، 96/0، 13/0 و 07/0 گرم در لیتر و در ترانشۀ خاکریزی به‌ترتیب 51/1، 06/1، 27/0 و 08/0 گرم در لیتر برآورد شد. نتایج تجزیۀ واریانس نشان داد که اختلاف معنی‌داری بین مقدار رواناب و رسوب ایجادشده در شدت‌های مختلف پوشش لاشبرگ و مازاد مقطوعات وجود دارد (05/0P< ). میانگین رواناب تولیدی در ترانشۀ خاکبرداری به‌طور معنی‌داری (05/0P< ) بیشتر از میانگین آنها در ترانشۀ خاکریزی در تمام درصدهای پوشش بود. نتایج نشان داد پوشش لاشبرگ و مازاد مقطوعات اثر معنی‌داری در کاهش رواناب و رسوب جاده‌های جنگلی دارد.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of litter cover and residuals on runoff and sediment in the cut slope and fill slope of forest roads

نویسندگان [English]

  • Seyed Reza Javadi 1
  • Ramin Naghdi 2
  • Mehrdad Nikooy 3
  • Mehrdad Mirzaei 4
1 Faculty of Natural Resources, University of Guilan, Someh sara, Iran.
2 Department of forestry faculty of natural resources University of Guilan
3 Faculty of Natural Resources, University of Guilan, Someh sara, Iran.
4 PhD graduated in Forestry Science, University of Guilan
چکیده [English]

One of the causes of instability of sloping hillsides is the construction of forest roads, which leads to soil erosion and its effects. The purpose of this study was to study the effects of litter cover and residuals on runoff and sediment in the cut slope and fill slope of forest roads in the forests of Guilan province. For this purpose, four cut slopes and fill slope were selected and in each of them, four plots (2 m2) with four litter cover and residuals including without cover, 30%, 60% and 90% and with a fixed slope of 30% was measured. Samples were measured after each rainfall with an approximate intensity of 80 mm/h. The results showed that the mean of runoff in the cut slope were 759.3, 748.6, 372.6 and 196 ml/m2, in the fill slope were 216.6, 156.6, 77.1 and 69.5 ml/m2, respectively. Mean of sediment in the cut slope were 1.08, 0.96, 0.13 and 0.07 g/l, in the fill slope were 1.51, 1.06, 0.27 and 0.08 g/l, respectively. The results of analysis of variance showed that there was a significant difference between the amount of runoff and sediment created in the litter cover and residuals classes (P<0.05). The mean of runoff produced in the cut slope was significantly (P<0.05) higher than their mean in the fill slope in all cover percentages. Results of the study showed that litter cover and residuals had a significant effect on reducing runoff and sediment in forests roads.

کلیدواژه‌ها [English]

  • Soil conservation
  • forest road
  • runoff and sediment
  • bioengineering
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