بررسی تغییر پذیری روان آب و تلفات خاک اندازه‌گیری شده در کرت‌های صحرایی

نوع مقاله : مقالات پژوهشی

نویسندگان

• فرخ اسدزاده ¹
• منوچهر گرجی اناری ²
• علیرضا واعظی ³
• سلمان میرزایی ⁴

¹ دانشگاه ارومیه

² تهران

³ دانشگاه زنجان

⁴ دانشگاه شهرکرد

https://doi.org/10.22067/jsw.v0i0.30931

چکیده

کرت های صحرایی به طور گسترده در مطالعات مربوط به اندازه گیری تلفات خاک و مدل سازی فرآیندهای فرسایش مورد استفاده قرار می گیرند. این تحقیق به منظور بررسی تغییرپذیری تلفات خاک و روان آب اندازه گیری شده از تکرار های مختلف کرت های صحرایی صورت گرفته است. برای این منظور هفت اندازة متفاوت کرت با سه تکرار در ایستگاه کوهین واقع در استان قزوین احداث شدند. کرت ها برای یک بازة زمانی 2 ساله به صورت آیش نگه داشته شده و مقادیر روان‌آب و تلفات خاک ناشی از هر رخداد به طور مجزا در کرت ها اندازه گیری شد. بر اساس نتایج، حداکثر مقدار ضریب تغییرات مقادیر مشاهده ای روان آب و رسوب در تکرار های کرت ها به ترتیب 60 و 80 درصد بود که این مقادیر در مقایسه با میزان تغییرات ویژگی های خاک در تکرارهای کرت ها زیاد بود. با افزایش میانگین تلفات خاک و روان آب در کرت های صحرایی ضریب تغییرات مقادیر اندازه گیری شدة روان آب و رسوب در تکرار های کرت ها به صورت توانی کاهش یافت. به دلیل احتمال خطای بیش تر در اندازه گیری تلفات خاک در مقایسه با روان آب، در بیش از 80 درصد موارد، ضریب تغییرات رسوب در تکرارهای کرت ها نسبت به ضریب تغییرات روان آب بیش تر بود. با افزایش ابعاد کرت ها نسبت ضریب تغییرات روان آب به ضریب تغییرات رسوب در تکرار های هر کرت کاهش یافت.

کلیدواژه‌ها

• خطای اندازگیری
• ضریب تغییرات
• فرسایش
• مدل سازی

20.1001.1.20084757.1394.29.3.12.9

عنوان مقاله [English]

Variability of Measured Runoff and Soil Loss from Field Plots

نویسندگان [English]

• F. Asadzadeh ¹
• manoochehr gorji ²
• A. Vaezi ³
• S. Mirzaee ⁴

¹ Urmia University

²

³ Zanjan University

⁴ Shahrekord University

چکیده [English]

Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes.
Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on storm basis using the collection tanks. The collected runoff from each plot was then mixed thoroughly and a sample was taken for determining sediment concentration by weight. The per-storm soil loss was then obtained.
Results and Discussion: A wide range of rainfall characteristics were observed during the study period.The results indicated that the maximum amount of coefficients of variation (CVs) for runoff and soil loss from replicated plots were 60 and 80 percent, respectively, which were considerably higher than the variability of soil characteristics from these plots. CV of runoff and soil loss data among the replicates decreased as a power function of mean runoff (R2= 0.661, P

کلیدواژه‌ها [English]

• Coefficient of variation
• Erosion
• Erosion Plot
• Soil Loss Measurement

مراجع

-Bagarello V., and Ferro V. 2004. Plot-scale measurement of soil erosion at the experimental area of Sparacia (southern Italy). Hydrological Processess, 18:141–157.

2-Bagarello V., and Ferro V. 2010. Analysis of soil loss data from plots of differing length for the Sparacia experimental area, Sicily, Italy. Biosystems Engineering, 105:411-422.

3-Boix-Fayos C., Martinez-Mena M., Arnau-Rosalen E., Calvo-Cases A., Castillo V., and Albaladejo J. 2006. Measuring soil erosion by field plots: Understanding the sources of variation. Earth Science Reviews, 78:267–285.

4- Boix-Fayos C., Martinez-Mena M., Calvo-Cases A., Arnau-Rosalen E., Albaladejo J., and Castillo V. 2007. Causes and underlying processes of measurement variability in field erosion plots in Mediterranean conditions. Earth Surface Processes and Landforms, 32:85-101.

5- Evans R. 1995. Some methods of directly assessing water erosion of cultivated land - a comparison of measurements made on plots and fields. Progress in Physical Geography, 19:115–129.

6- Gomez J.A., Nearing M.A., Giraldez J.V., Alberts E.E. 2001.Analysis of sources of variability of runoff volume in a 40 plot experiment using a numerical model. Journal of Hydrology, 248:183–197.

7- Gomez J. A., Vanderlinden K., and Nearing M. A. 2005. Spatial variability of surface roughness and hydraulic conductivity after disk tillage: implications for runoff variability. Journal of Hydrology, 311:143–156.

8- Gonzalez-Hidalgo J. C., Peña-Monne J. L., and de Luis M. 2007. A review of daily soil erosion in Western Mediterranean areas. Catena, 71:193–199.

9- Hudson N.W. 1993. Field Measurement of Soil Erosion and Runoff. FAO Soils Bulletin, vol. 68. FAO, Rome.

10-Nearing M.A., Gover G., and Norton L.D. 1999. Variability in soil erosion data from replicated plots. Soil Science Society of America Journal, 63:1829–1835.

11-Nearing M.A. 2000. Evaluating soil erosion models using measured plot data: Accounting for variability in the data. Earth Surface Processes and Landforms, 25:1035-1043

12- Parsons A.J., Brazier R.E., Wainwright J., and Powell D.M. 2006. Scale relationships in hillslope runoff and erosion. Earth Surface Processes and Landforms, 31:1384–1393.

13- Rejman J., Usowicz B., andDebicki R. 1999. Source of errors in predicting soil erodibility with USLE. Polish Journal of Soil Science, 32(1) : 13–22.

14- Rüttiman M., Schaub D., Prasuhn V., and Rüegg W. 1995. Measurement of runoff and soil erosion on regularly cultivated fields in Switzerland-some critical considerations. Catena, 25:127–139.

15- Sadeghi S.H.R., Mizuyama T., and Ghaderi-Vangah B. 2007. Conformity of MUSLE Estimates and Erosion Plot Data for Storm-Wise Sediment Yield Estimation. Terrestrial, Atmospheric and Oceanic Sciences, 18(1):117-128.

16- Sadegi H. R., Pourghasemi H.R., Mohammadi M., and Agharazi H. A. 2009. Applicability of Rainfall and Runoff Variables in Estimation of Storm-Wise Sediment Yield from Experimental Plots with Different Land Uses, Agricultural Sciences and Technology Journal (Water and Soil). 22(1): 113-122. (in Persian with English abstract)

17- Sadeghi S.H.R., Bashari-Seghaleh M., and Rangavar A.S. 2013. Plot sizes dependency of runoff and sediment yield estimates from a small watershed, Catena, 102:55-61.

18- Smets T., Poesen J., and Bochet E. 2009. Impact of plot length on the effectiveness of different soil-surface covers in reducing runoff and soil loss by water. Progress in Physical Geography, 32(6):654–677.

19- Vaezi A.R., Sadeghi S.H.R., Bahrami H.A., and Mahdian M.H. 2008. Modeling the USLE K-factor for calcareous soils in northwestern Iran. Geomorphology, 97:414–423.

20- Vaezi A.R., Bahrami H., Sadeghi H. R., and Mahdian M. H. 2009. Evaluating Erosivity Indices of the USLE, MUSLE, RUSLE and USLE-M Models in Soils of a Semi-Arid Region in Northwest of Iran. Iranian Journal of Watershed Management Science and Engineering, 2(4): 25-37. (in Persian with English abstract)

21-Wendt R.C., Alberts E.E., and Hjelmfelt-Jr A.T. 1986. Variability of runoff and soil loss from fallow experimental plots. Soil Science Society of America Journal, 50:730–736.

22-Wischmeier W.H., Smith D.D. 1978. Predicting Rainfall-Erosion Losses: A Guide to 22-Conservation Planning. U.S. Department of Agriculture. Agriculture Handbook. NO, 537