Document Type : Research Article

Authors

Department of Soil Science, Faculty of Agriculture, University of Zanjan

Abstract

Introduction: Rills are usually found on the sloping fields worldwide, especially in semi-arid slopes, where vegetation covers are often poor and soils are weakly aggregated. Rill erosion is recognized as an important process of water erosion on agricultural land in these regions and causes a grate amount of soil loss. Understanding rill erosion rate is important in the prediction of soil erosion and the prevention of soil loss in the lands. Rill erosion is often easy to observe but difficult to measure because of its complexity and stochastic nature. A common method used to determine rill erosion rate is measuring sediment concentration distribution of eroding rill flow under different flow rates. However, it is not only time-consuming but also had to measure. The volume Replacement Method is an easy method to estimate soil loss from rills in the sloped lands. Limited information is available concerning the ability of this method in different soil textures under slope gradients. Therefore, this study was conducted to evaluate the ability of the method to estimate rill erosion of semi-arid soils.
Materials and Methods: This study was conducted on three different soil textures i.e. loam, clay loam and sandy clay loam under four slope gradients including 5, 10, 15 and 20% using factorial arrangement based on completely randomized block design with three replications in the laboratory. A flume with 0.3 m width and 4 m length was subdivided into strips of 0.1 m width and 4 m length to imitate eroding rills. Soil samples for each soil texture were passed from 8-mm sieve and packed into the flumes at its bulk density in the field. Prior to each experimental run, the soil materials were pre-wetted to reach to water-holding capacity. Tap water was introduced into the rill from the upper end, through a water supply tank and a pump at a constant flow rate of 0.5 L.min-1. After erosion, the flume was lowered to the horizontal position for the measurements of eroded rill volumes. The rill volume was determined using soil samples passed from a 2-mm sieve. Soil loss mass eroded from soil surface was computed using rill volume and original soil bulk density packed into the flume. This value was considered as estimated value using the Volumetric Replacement Method for each soil texture under different slope gradients. The performance of the method was assessed using the measured data for each soil and slope gradient using error measures such as root mean square error (RMSE) and mean absolute error (ME).
Results and Discussion: Significant differences were found among soil textures and slope gradients as well as their interaction on rill erosion rate. The highest rill erosion rate was observed in clay loam (3.166 g.m-2.s-1), whereas sandy clay loam showed the minimum susceptibility to rill detachment (0.962 g.m-2.s-1). Higher fine particles (clay) and lower aggregation as well as weak aggregate stability are the major reasons for higher susceptibility of clay loam to rill erosion. The rill erosion was more sensitive to slope gradient than soil texture and the strongest dependency of rill erosion on slope gradient was found in clay loam (R2= 0.99). With an increase in slope gradient, rill erosion strongly increased except for loam. The Volumetric Replacement Method overestimated rill erosion in all soils and slope gradients. The highest overestimation was observed in sandy clay loam (RMSE= 2.72 g/m2.sec and ME= 7.02 g/m2.sec), whereas the lowest overestimation value was in loam (RMSE= 0.60 g/m2.sec and ME= 3.86 g/m2.sec). The performance of the Volumetric Replacement Method decreased in higher slope gradients and the highest overestimation was observed under 20% slope gradient (RMSE=1.86 g/m2.sec and ME= 3.84 g/m2.sec).
Conclusion: Rill erosion is strongly affected by soil texture and slope gradient. Particle size distribution, aggregates percentage and their stability can control the soil’s susceptibility to detach by concentrated water flow. The Volumetric Replacement Method showed higher uncertainty as evaluated in the semi-arid soil textures especially under steep slopes. The change of soil physical properties by water flow especially bulk density result in errors in determination of rill volume by using this method. The higher change of physical properties by concentrated flow occurs in fine soil textures and steeper slopes. Additionally, continuous sedimentation along the rills imposes other errors in estimating soil loss mass from the rills.

Keywords

  1. Aksoy H., Unal N. E., Cokgor S., Gedikli A., Yoon J., Koca K., and Pak G. 2013. Laboratory experiments of sediment transport from bare soil with a rill. Hydrological sciences Journal 58(7): 1505-1518.
  2. Asadi H., Aligoli M., and Gorji M. 2017. Dynamic Changes of Sediment Concentration in Rill Erosion at Field Experiments. JWSS-Isfahan University of Technology 20(78): 125-139. (In Persian)
  3. Bagnold R.A. 1966. An approach to the sediment transport problem from general physics. US government printing office.
  4. Blake G.R., and Hartge K.H. 1986. Bulk Density 1. Methods of Soil Analysis: Part 1—Physical and Mineralogical Methods, (methodsofsoilan1), 363-375.
  5. Bonilla C.A., and Johnson O.I. 2012. Soil erodibility mapping and its correlation with soil properties in Central Chile. Geoderma 189: 116-123.
  6. Casalí J., Loizu J., Campo M.A., De Santisteban L.M., and Álvarez-Mozos J. 2006. Accuracy of methods for field assessment of rill and ephemeral gully erosion. Catena 67(2): 128-138.
  7. Cerdan O., Le Bissonnais Y., Couturier A., Bourennane H., and Souchère V. 2002. Rill erosion on cultivated hillslopes during two extreme rainfall events in Normandy, France. Soil and Tillage Research 67(1): 99-108.
  8. Chen X.Y., Huang Y.H., Zhao Y., Mo B., Mi H.X., and Huang C.H. 2017. Analytical method for determining rill detachment rate of purple soil as compared with that of loess soil. Journal of Hydrology 549: 236-243.
  9. Chen X.Y., Zhao Y., Mi H.X., and Mo B. 2016. Estimating rill erosion process from eroded morphology in flume experiments by volume replacement method. Catena 136: 135-140.
  10. Chen X.Y., Zhao Y., Mo B., and Mi H.X. 2014. An improved experimental method for simulating erosion processes by concentrated channel flow. Plos one 9(6): e99660.
  11. Fallow D.J., Elrick D.E., Reynolds W.D., Baumgartner N., and Parkin G.W. 1994. Field measurement of hydraulic conductivity in slowly permeable materials using early-time infiltration measurements in unsaturated media. In Hydraulic conductivity and waste contaminant transport in soil. ASTM International.
  12. Felton G.K. 1995. Temporal variation of soil hydraulic properties on municipal solid waste amended mine soils. Transactions of the ASAE 38(3): 775-782.
  13. Fenli Z. 1989. A Research on Method of Measuring Rill Erosion Amount [J]. Bulletin of Soil and Water Conservation, 4.
  14. Gao Y., Zhu B., He N., Yu G., Wang T., Chen W., and Tian J. 2014. Phosphorus and carbon competitive sorption–desorption and associated non-point loss respond to natural rainfall events. Journal of Hydrology 517: 447-457.
  15. Ghose D.K., and Samantaray S. 2019. Estimating Runoff Using Feed-Forward Neural Networks in Scarce Rainfall Region. In Smart Intelligent Computing and Applications (pp. 53-64). Springer, Singapore. RMSE
  16. Goodarzi M.S., Amiri B.J., and Navardi S. 2018. Investigating the Optimization Strategies on Performance of Rainfall-Runoff Modeling. EPiC Series in Engineering, 3: 827-835. RMSE VAAAAAa ME
  17. Govers G., Giménez R., and Van Oost K. 2007. Rill erosion: exploring the relationship between experiments, modelling and field observations. Earth-Science Reviews 84(3-4): 87-102.
  18. Huang Y., Chen X., Luo B., Ding L., and Gong C. 2015. An experimental study of rill sediment delivery in purple soil, using the volume-replacement method. PeerJ 3: e1220.
  19. Jin K., Cornelis W. M., Gabriels D., Baert M., Wu H.J., Schiettecatte W., ... and Hofman G. 2009. Residue cover and rainfall intensity effects on runoff soil organic carbon losses. Catena 78(1): 81-86.
  20. Klute A. 1986. Water retention: Laboratory methods, Methods of Soil Analysis, Part I, A. Klute, 635–660. Am. Soc. Agron., Madison, Wisc.
  21. Kowalska J.B., Zaleski T., Józefowska A., and Mazurek R. 2019. Soil formation on calcium carbonate-rich parent material in the outer Carpathian Mountains–A case study. Catena 174: 436-451.
  22. Lei T.W., Zhang Q.W., and Yan L.J. 2009. Physically-based rill erosion model.
  23. Liu F., Zhang G. H., Sun L., and Wang H. 2016. Effects of biological soil crusts on soil detachment process by overland flow in the Loess Plateau of China. Earth Surface Processes and Landforms 41(7): 875-883.
  24. Ma Y., Lei T., and Xiusheng Y. 2015. Volume replacement method for partitioning contents of rocks, soil particles and water mixture. Transactions of the Chinese Society of Agricultural Engineering 31(9): 85-91.
  25. Miao C., Ni J., Borthwick A.G., and Yang L. 2011. A preliminary estimate of human and natural contributions to the changes in water discharge and sediment load in the Yellow River. Global and Planetary Change 76(3-4): 196-205.
  26. Mirhasani M., Rostami N., Bazgir M., and Tavakoli M. 2019. Threshold friction velocity and soil loss across different land uses in arid regions: Iran. Arabian Journal of Geosciences 12(3): 91.
  27. Najafi A., Solgi A., and Sadeghi S.H. 2009. Soil disturbance following four wheel rubber skidder logging on the steep trail in the north mountainous forest of Iran. Soil and Tillage Research 103(1): 165-169.
  28. Pansu M., and Gautheyrou J. 2007. Handbook of soil analysis: mineralogical, organic and inorganic methods. Springer Science and Business Media.
  29. Poesen J., Nachtergaele J., Verstraeten G., and Valentin C. 2003. Gully erosion and environmental change: importance and research needs. Catena 50(2-4): 91-133.
  30. Refahi H. 2015. Water erosion and control, Tehran: university of Tehran press, 8th Edition. (In Persian)
  31. Refahi H.G. 2003. Water erosion and control, Tehran: university of Tehran press.
  32. Ries J.B., and Hirt U. 2008. Permanence of soil surface crusts on abandoned farmland in the Central Ebro Basin/Spain. Catena 72(2): 282-296.
  33. Romero C.C., Stroosnijder L., and Baigorria G. A. 2007. Interrill and rill erodibility in the northern Andean Highlands. Catena 70(2): 105-113.
  34. Shen H., Zheng F., Wen L., Han Y., and Hu W. 2016. Impacts of rainfall intensity and slope gradient on rill erosion processes at loessial hillslope. Soil and Tillage Research 155: 429-436.
  35. Su Z.L., Zhang G.H., Yi T., and Liu F. 2014. Soil detachment capacity by overland flow for soils of the Beijing region. Soil Science 179(9): 446-453.
  36. Sumner M. E. 1993. Sodic soils-New perspectives. Soil Research 31(6): 683-750.
  37. Toy T.J., Foster G.R., and Renard K.G. 2002. Soil erosion processes, prediction measurement under simulated rainfall. Journal of Soil Science 150: 787-798.
  38. Vaezi A.R., and Ebadi M. 2017. Particle size distribution of surface-eroded soil in different rainfall intensities and slope gradients. Journal of Water and Soil 31(1): 216-29. (In Persian with English abstract)
  39. Walkley A., and Black I. A. 1934. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Science 37(1): 29-38.
  40. Wang Y.C., and Lai C.C. 2018. Evaluating the erosion process from a single-stripe laser-scanned topography: A laboratory case study. Water 10(7): 956.
  41. Yuequn D., Fang L., Qingwen Zh., Tingwu L. 2015. Determining ephemeral gully erosion process with the volume replacement method, CATENA (131): 119-124.
  42. Zheng F.L. 1998. Study on interrill erosion and rill erosion on slope farmland of loess area. Acta Pedologica Sinica 35(1): 95–103. (In Chinese)
CAPTCHA Image