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نوع مقاله : مقالات پژوهشی

نویسندگان

دانشگاه زنجان

چکیده

آگاهی از میزان تغییرات رواناب و رسوب در رخدادهای باران می تواند در مدل سازی تولید رواناب و رسوب مفید واقع شود. از این رو این پژوهش با هدف بررسی تولید رواناب و رسوب خاکدانه ها طی رخدادهای یکسان باران در خاک کشاورزی به اندازه های مختلف خاکدانه انجام رسید. برای انجام این پژوهش، پنج کلاس اندازه خاکدانه از یک خاک لوم رس شنی به وسیله الک های مربوطه نمونه برداری شد. خاکدانه ها تا عمق 10 سانتی متری به پانزده فلوم با ابعاد 100 سانتی متر × 50 سانتی متر و عمق 15 سانتی متر در سه تکرار منتقل شد. سپس فلوم های محتوی خاکدانه در شیب 9 درصد قرار گرفته و تحت 10 رخداد باران شبیه سازی شده با شدت یکسان 60 میلی متر بر ساعت به مدت 30 دقیقه و فواصل زمانی پنج روز قرار گرفتند. در پایان هر رخداد مقدار رواناب و رسوب تولید شده در ظروف انتهای فلوم ها جمع آوری و اندازه گیری شد. نتایج نشان داد که تفاوتی معنی دار بین رخدادها از نظر رواناب (05/0p

کلیدواژه‌ها

عنوان مقاله [English]

Runoff and Sediment Production under the Similar Rainfall Events in Different Aggregate Sizes of an Agricultural Soil

نویسندگان [English]

  • S. F. Eslami
  • A. R. Vaezi

University of Zanjan

چکیده [English]

Introduction: Soil erosion by water is the most serious form of land degradation throughout the world, particularly in arid and semi-arid regions. In these areas, soils are weakly structured and are easily disrupted by raindrop impacts. Soil erosion is strongly affected by different factors such as rainfall characteristics, slope properties, vegetation cover, conservation practices, and soil erodibility. Different physicochemical soil properties such texture, structure, infiltration rate, organic matter, lime and exchangeable sodium percentage can affect the soil erodibility as well as soil erosion. Soil structure is one of the most important properties influencing runoff and soil loss because it determines the susceptibility of the aggregates to detach by either raindrop impacts or runoff shear stress. Many soil properties such as particle size distribution, organic matter, lime, gypsum, and exchangeable sodium percentage (ESP) can affect the soil aggregation and the stability. Aggregates size distribution and their stability can be changed considerably because of agricultural practices. Information about variations of runoff and sediment in the rainfall events can be effective in modeling runoff as well as sediment. Thus, the study was conducted to determine runoff and sediment production of different aggregate sizes in the rainfall event scales.
Materials and Methods: Toward the objective of the study, five aggregate classes consist of 0.25-2, 2-4.75, 4.75-5.6, 5.6-9.75, and 9.75-12.7 mm were collected from an agricultural sandy clay loam (0-30 cm) using the related sieves in the field. Physicochemical soil analyses were performed in the aggregate samples using conventional methods in the lab. The aggregate samples were separately filed into fifteen flumes with a dimension of 50 cm × 100 cm and 15-cm in depth. The aggregate flumes were fixed on a steel plate with 9% slope and were exposed to the simulated rainfalls for investigating runoff and soil loss (sediment). Ten same rainfall events with 60 mm h-1 in intensity for 30 min were applied using a designed rainfall simulator in the lab. The rainfall simulator had a rainfall plate with a dimension of 100 cm × 120 cm which has been fixed on a metal frame with 3m height from the ground surface. Runoff and sediment samples were collected using a plastic container placed the out-let of the flumes. Runoff generation of each flume was determined based on multiplying total content volume of the tank by volume proportion of water in the sample. Soil loss for each event was determined using multiply the container volume and sediment concentration of the uniform sample. Initial soil moisture was measured in the aggregate samples before each rainfall event in order to investigate its effect on the runoff and sediment variations in the event scales. Runoff, soil loss and initial soil moisture data were evaluated for normality before any statistical analysis using SPSS version 18 software. Differences of runoff and soil loss among different rainfall events were analyzed using the Duncan's test.
Results and Discussion: Based on the results, the soil was calcareous having 16% equivalent calcium carbonate. Low amount of organic matter (0.6%). The measured aggregate stability showed to be very low, indicating high susceptibility of the aggregates to water erosion processes. Significant differences were found among the rainfall events in runoff (p< 0.05), sediment (p< 0.001) and sediment concentration (p< 0.001) which were associated with aggregate breakdown by raindrop impacts in the rainfall events. Runoff and sediment were strongly increased from each event to other event. Significant relationship was found between sediment and runoff in the events (R2= 0.89, p< 0.001). However, sediment showed to have higher increasing trend as compared to runoff variation pattern in the event scale. Sediment value was very low in the first rainfall event due to high portions of the water-stable aggregates and low level of soil moisture. Difference in runoff from each event to other event was directly related to variation of infiltration rate. In the final events, aggregate disruption was strongly enhanced and remarkably decreased the soil infiltration rate so runoff and sediment significantly increased. After seventh rainfall event, sediment production was observed to be higher (2.93 times) as compared with runoff production and in consequence sediment concentration strongly increased. The difference in the infiltration rate among the rainfall events was attributed with differences in initial soil moisture and macropores.

کلیدواژه‌ها [English]

  • Aggregate
  • runoff
  • Sediment Concentration
  • Simulated Rainfall
1- Amezketa E., Singer M.J., and Le Bissonnais Y. 1996. Testing a new procedure for measuring water-stable aggregation, Soil Science Society of America Journal, 60: 5,888-894.
2- Assouline S. and Ben-Hur M. 2006. Effects of rainfall intensity and slope gradient on the dynamics of interrill erosion during soil surface sealing. Catena. 66: 211-220.
3- Baihua F., Lachlan, T.H., Newham C.E., and Ramos-Scharron 2010. A review of surface erosion and sediment delivery models for unsealed roads, Soil Science Society of America Journal. 24: 11,834-840.
4- Begueria H., Slopa C., Haink F., Aseto D., and Kanin, P. 2006. Water stability of aggregates in subtropical and tropical soils and its relationships with the mineralogy and chemical properties, Eurasian Soil Science, 42: 5,415-425.
5- Blanco H., and Lal R. 2008. Principles of Soil Conservation and Management. Springer Science, pp: 1-46.
6- Bouwer H., and Jackson R.D. 1974. Determining soil properties, pp. 611-627, Drainage for Agriculture, ASA Monograph Noumber 17, Madison, WI.
7- Canton Y., Sole-benet A., Asensio C., Chamizo S., and Puigdefabregas J. 2009. Aggregate Stability in range sandy soils relationships with runoff and sediment, Original research article Catena, Journal homepage, Elsevier, 14: 8,192-199.
8- Cattan D., Lan Z.H., and David AB. 2012. Effect of soil physical on runoff and sediment concentration under rain, Soil Science Society of America Journal, 20: 10,531-539.
9- Chapman H.D., and Pratt P.F. 1978. Methods of analysis for soils, plants and waters, Division of agricultural sciences, University of California, United State of America.
10- Cheng Q. Ma W., and Cai Q. 2008. The relative importance of soil crust and slope angle in runoff and soil loss: A case study in the hilly areas of the Loess Plateau, North China. Geo. J. 71: 117-125.
11- Culley J.L. B. 1993. Density and compressibility, pp. 529-540, soil sampling and methods of analysis, Lewis published in United State of America.
12- Duiker S.W., Flanagan D.C., and Lal R. 2001. Erodibility and infiltration characteristics of five major soils of southwest Spain, Catena, 34: 103-121.
13- Endale D. M., Fisher D. S., and Steiner J. L. 2006. Hydrology of a zero-order southern Piedmont watershed through 45 year of changing agricultural land use, Monthly and seasonal rainfall runoff relationship, Journal of Hydrology, 316: 1-12.
14- Foltz R.B., Copeland N.S., and Elliot W.J. 2009. Reopening abandoned forest roads in northern Idaho, USA: Qua sediment concentration, infiltration, and interrill erosion parameters, Journal of Environmental Management, 90: 2542-2550.
15- Gee G.W., and Bauder J.W. 1986. Particle-size analysis, pp. 383-411, Methods of Soil Analysis. Part 1, ASA and SSSA, Madison, WI.
16- Girmay G., Sing B.R., Nyssen J., and Borrosen T. 2009. Runoff and sediment associated nutrient losses under different land uses in Tigray, Northern Ethiopia, Journal of Hydrology, 376: 70-80.
17- Gupta O.P. 2002. Water in relation to soils and plants. Agrobios, India, pp: 31-34.
18- Hamidi Nehrani S., Vaezi A. R., Mohammadi M. H., and Saba G. 2011. Efficency of polyvinyl acetate in reducing runoff and sediment in a marl soil under rainfall events. .Iranina Jouirnal of Soil and Water Research, 43 (2), 179-184. (In Persian).
19- Hasanzadeh H., Vaezi A. R., and Mohammadi M. H. 2013. Runoff variation in the same rainfall events in different soil textures.Iranina Jouirnal of Soil and Water Research, 44 (3), 243-253. (In Persian).
20- Huntigton T.G. 2003. Climate warming could reduce runoff significantly in New England, USA, Agricultural and Forest Meteorology, 117: 193-201.
21- Jackson M.L. 1967. Soil chemical analysis, Prentice-Hall of India, Private Limited, New Delhi.
22- Jin K., Cornelis W.M., and Gabriels D. 2008. Soil management effects on runoff and soil loss from field rainfall simulation. Catena, 75: 191-199.
23- Keli Z., Shuancai L., and Wenyering P. 2002. Erodibility of Agriculture Soils in the Loess Plateau of China, In 12th ISCO, Beijing, 551-558.
24- Khazaee M., Sadeghi S. H. R., and Mirnia S. Kh. 2013. Comparsion of runoff and soil erosion in farest soils. 6th. Nation Seminar on Wtarershed Management Science and Management. College of Natural Resources and Marine Sciences, Tarbiat Modarres University, 8-9 Mars. (In Persian).
25- Kirkby M. J., and Morgan R. P. 2010. Soil erosion, John Wiley and Sons, New York.
26- Klute A. 1986. Methods of soil analysis, Agron. 9, Part 1, American Society of Agronomy, Madison, WI, United State of America.
27- Kramer G. 2010. Dynamic model of daily rainfall, runoff and sediment yield for a Himalayan watershed, Soil Science Society of America Journal, 36: 951-960.
28- Mohammadi. M., and Kavian E. 2010. Temporal variation of runoff and sediment in the plot scale. 12th. Iranian Soil Science Congress, Tabriz, 12-14 September. 1786-1788. (In Persian).
29- Nelson D.W., and Sommers L. E. 1982. Total carbon, organic carbon, and organic matter, pp. 539-579, Methods of soil analysis, ASA and SSSA, Madison, WI.
30- Rabinson B.S. 2006. The role of the plant cover in soil resistance and decrease erosion, Soil Science Society of America Journal, 19: 41-52.
31- Rhoades J.D. 1982. Cation exchange capacity, pp. 149- 157, Methods of soil analysis, Agronomy, Noumber. 9, chemical and mineralogical properties, Society. Agronomy, Madison. WI, USA.
32- Richard L.A. 1954. Diagnosis and improvement of saline and alkali soils, USDA Handbook 60, Washington DC, pp. 160.
33- Vaezi. A. R., Bahrami, H., Sadeghi. S. H. R., and Mahdian M. H. 2009. A new nomograph for estimating soil erodibility in some soils of the semi-arid regions in northwest of Iran. 13 (49), 69-79. (In Persian).
34- Vahabi J., and Mahdian M.H. 2008. Rainfall simulation for the study of the effects of efficient factors on runoff rate. Current Sci. 95: 1439-1445.
35- Valettea G., Prevosta S., and Lucasa L. 2006. A simulation of soil surface degradation by rainfall. Computers and Graphics, 30: 494–506.
36- Wallas P. H., Duson L. J., and Miyer I. G. 2013. Yearly soil erodibility variation in Sevil. Soil Science Society of America Journal, 25: 321-329.
37- Williams B.M., Martinez-Menaa S., and Deeksb L. 2004. Exponential distribution theory and aggregate erosion, Soil Science Society of America Journal, 6: 382-391.
38- Willy K.N. 2011. The role of the aggregate size in soil resistance and decrease erosion, Soil Science Society of America Journal, 10: 111-120.
39- Wu S.F., Wu P.T., Feng H., and Bu C.F. 2010. Influence of amendments on soil structure and soil loss under simulated rainfall China’s loess plateau. African Journal of Biotechnology, 9(37): 6116-6121.
40- Zhang K., Li S., Peng W., and Yu B. 2004. Erodibility of Agricultural Soils and Loess Plateau of China. Soil Till. Res., 76: 157-165.
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