Environmental Erosion Research
پژوهش هاي فرسايش محيطي
E.E.R.
Literature & Humanities
http://magazine.hormozgan.ac.ir
1
admin
2251-7812
2717-3968
10.52547/jeer
6561
8888
45855/11/3/90
fa
jalali
1395
8
1
gregorian
2016
11
1
6
3
online
1
fulltext
fa
مقایسه اثر وتیور و پلیاکریل آمید بر شاخصهای پایداری ساختمان و فرسایش خاک
Comparing the Effects of Vetiver and Polyacrylamide on Soil Structural Stability and Erosion Indices
مدیریت و کنترل اثرات فرسایش محیطی
پژوهشي
Research
<p dir="RTL"><strong>فرسایش خاک یکی از مهم</strong><strong>ترین مشکلات محیط زیست، منابع طبیعی و کشاورزی در جهان است. پایداری ساختمان خاک عنصر کلیدی سلامتی خاک است که یکی از عوامل اصلی در ارزیابی عملیات کنترل فرسایش آن به شمار می­رود. پژوهش حاضر به منظور بررسی اثر سیستم کشت وتیور به عنوان یک</strong> <strong>ابزار</strong> <strong>بیو</strong><strong>مهندسی</strong> <strong>ارزنده </strong><strong>و پلی­اکریل آمید (</strong><strong><span dir="LTR">PAM</span></strong><strong>)، بر شاخص</strong><strong>های پایداری خاکدانه و ساختمان خاک و شاخص</strong><strong>های فرسایش آن در شرایط میدانی بر خاکی لوم در شیب </strong><strong>۵</strong><strong> درصد انجام شد. تیمار</strong><strong>های آزمایش شامل تیمار کشت گیاه وتیور (</strong><strong><span dir="LTR">VP۰</span></strong><strong>)، کاربرد </strong><strong><span dir="LTR">PAM</span></strong><strong> در دو سطح </strong><strong>۲۰</strong><strong> (</strong><strong><span dir="LTR">P۲</span></strong><strong>) و </strong><strong>۴۰</strong><strong> (</strong><strong><span dir="LTR">P۴</span></strong><strong>) کیلوگرم در هکتار، کاربرد همزمان وتیور و هر دو سطح </strong><strong><span dir="LTR">PAM</span></strong><strong> (</strong><strong><span dir="LTR">VP۲</span></strong><strong> و </strong><strong><span dir="LTR">VP۴</span></strong><strong>) و تیمار شاهد (</strong><strong><span dir="LTR">P۰</span></strong><strong>) بود. شاخص</strong><strong>های پایداری شامل میانگین وزنی قطر خاکدانه در حالت مرطوب (</strong><strong><span dir="LTR">MWD<sub>wet</sub></span></strong><strong>) و خشک (</strong><strong><span dir="LTR">MWD<sub>dry</sub></span></strong><strong>)، پایداری خاکدانه (</strong><strong><span dir="LTR">AS</span></strong><strong>)، شاخص پایداری (</strong><strong><span dir="LTR">SI</span></strong><strong>)، و درصد تخریب خاکدانه­ها (</strong><strong><span dir="LTR">PAD</span></strong><strong>) تعیین شد. بارش با شدت </strong><strong>۳۰</strong><strong> میلی</strong><strong>متر در ساعت به مدت </strong><strong>۳۰</strong><strong> دقیقه با استفاده از سامانه­ی شبیه­ساز باران، اعمال و رواناب</strong> <strong>و</strong> <strong>رسوب</strong> <strong>تولید شده­ی بارش جمع</strong><strong>آوری شد. نتایج نشان داد که وتیور و </strong><strong><span dir="LTR">PAM</span></strong><strong>، شاخص</strong><strong>های پایداری </strong><strong><span dir="LTR">MWD<sub>wet</sub></span></strong><strong>، </strong><strong><span dir="LTR">MWD<sub>dry</sub></span></strong><strong>، </strong><strong><span dir="LTR">AS</span></strong><strong>، </strong><strong><span dir="LTR">SI</span></strong><strong> را افزایش و </strong><strong><span dir="LTR">PAD</span></strong><strong> را کاهش دادند؛ البته تأثیر وتیور در افزایش شاخص</strong><strong>های پایداری بسیار بیشتر از </strong><strong><span dir="LTR">PAM</span></strong><strong> بود. همچنین وتیور و </strong><strong><span dir="LTR">PAM</span></strong><strong> ، شاخص</strong><strong>های فرسایش را کاهش دادند و کاهش فرسایش و رواناب و ضریب رواناب بیشتر تحت­تأثیر وتیور بود. به طور کلی، براساس نتایج این پژوهش کاربرد وتیور به عنوان یک روش بیو</strong><strong>مهندسی کم</strong><strong>هزینه و با</strong><strong>دوام برای افزایش پایداری خاکدانه و ساختمان خاک، و کاهش رواناب و هدر</strong><strong>رفت خاک در مناطق نیمه­خشک مانند ایران پیشنهاد می</strong><strong>شود.</strong></p>
<p><strong>Extended abstract</strong></p>
<p><strong>1- INTRODUCTION</strong></p>
<p>Soil erosion is one of the most important problems of the environment, natural resources, and agriculture in the world. Soil structure stability is the key element of soil health, the main factor in the improvement or degradation of soils, and the important point in evaluating the effects of land management and the operations practices to control soil erosion. Bioengineering systems and soil stabilizers such as chemical polymers are applied to increase the soil structural stability and resistance against degradative agents, and to control soil erosion.</p>
<p><strong>2- THEORETICAL FRAMEWORK</strong></p>
<p>Although many researches have been carried out to study the effect of PAM on soil strcutursl stability and soil erosion, most of them were conducted in the lab condition, and also the mixture of PAM with the bioengineering techniques, especially in field condition and semi-arid regions such as Khorasan Razavi province, was not studied. Regarding the potential of vetiver in soil conservation, it seems that the vetiver has been well adapted in most regions of Iran, and can decrease soil erosion. Therefore, this research was performed to investigate the effect of the vetiver cultivation system, as a valuable bioengineering technique, and polyacrylamide (PAM) on soil structure and aggregate stability indices and soil erosion characteristics in a loamy soil under field condition.</p>
<p><strong>3- METHODOLOGY</strong></p>
<p>The study was conducted in a loamy soil on slope of 5% in Agriculture Campus, Ferdowsi University of Mashhad. To apply the treatments, experimental plots (1 m × 1 m) were prepared in the given area. Experimental treatments include vetiver cultivation (VP0), PAM (20 (P2) and 40 (P4) kg ha<sup>-1</sup>), simultaneous application of vetiver and above PAM concentrations (VP2, and VP4. In addition, P0 (no PAM and vetiver) was regarded as control treatment. The undisturbed samples were collected to measure the structure indices before and after simulating the rainfall test. Structural stability indices including wet and dry mean weight diameter of aggregates (MWD<sub>wet</sub> and MWD<sub>dry</sub>), aggregate stability (AS), structural stability index (SI), and the percentage of aggregate degradation (PAD) were determined. The simulated rainfall intensity of 30 mm h<sup>-1</sup> during 30 minutes was applied on the treated soils, and runoff and sediment volume were collected. This study was performed based on the randomized complete blocks design and a factorial arrangement with 3 replications. The data pertaining to soil structural stability and erosion indices were analyzed using SPSS software.</p>
<p></p>
<p><strong>4- RESULTS & DISCUSION </strong></p>
<p>The results showed that vetiver and PAM increased the soil structural stability indices i.e. MWD<sub>wet</sub>, MWD<sub>dry</sub>, AS, and SI, and decreased PAD. However, vetiver enhanced the stability indices more than PAM. Also, vetiver and PAM decreased soil erosion indices, and the decrease in soil loss, runoff, and runoff coefficient was more due to the vetiver. The higher aggregation and structural stability, and as a result, the considerable reduction of aggregate degradation in the vetiver plots is due to the effect of high density of fine roots biomass and microbial activity associated with the rhizosphere of the vetiver grass. On the other hand, when the aggregate stability increases, the water infiltration will increase and runoff will decrease. Consequently, particle detachment and aggregate degradation, and transport of soil particles due to the rain drop impact and runoff decrease. Also, vetiver increases soil resistance against raindrops; soil erosion decreases runoff probably through binding soil particles, aggregation and creating the macro pores. Adsorption of the long chains of PAM polymer on the surfaces of soil particles and aggregates, flocculating the soil particles and binding them by PAM ledad to increase aggregation and aggregate stability, creates continuous and stable macropores in soils, and decreases aggregate degradation. Therefore, PAM increases water permeability and as a results decreases the runoff, coefficient of runoff and soil loss. However, the efficiency of PAM to decrease the runoff and soil loss depends on the concentration and viscosity of the dissolved PAM.</p>
<p><strong>5- CONCLUSIONS AND SUGGESTIONS</strong></p>
<p>Generally, the results of this research indicated that the vetiver system can be recommended due to the very low cost and long-term bioengineering technique to improve the soil structure; it increases aggregate stability, and decreases runoff and soil loss in thesemi-arid regions such as Iran.</p>
پایداری خاکدانه, حفاظت زیستی خاک, رواناب, هدررفت خاک, شبیهساز باران
Aggregate stability, Soil biological conservation, Runoff, Soil loss, Rainfall simulator
71
90
http://magazine.hormozgan.ac.ir/browse.php?a_code=A-10-465-1&slc_lang=fa&sid=1
Elham Amiri
Khaboushan
الهام
امیری
elham1575@gmail.com
10031947532846004063
10031947532846004063
No
فردوسی مشهد
Hojat
Emami
حجت
امامی
hemami@um.ac.ir
10031947532846004064
10031947532846004064
Yes
فردوسی مشهد
Ali Rreza
Astaraei
علیرضا
آستارایی
astaraei@um.ac.ir
10031947532846004065
10031947532846004065
No
فردوسی مشهد
Mohammad Reza
Mosaddeghi
محمدرضا
مصدقی
mosadeqi@iut.ac.ir
10031947532846004066
10031947532846004066
No
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