坡面草带分布对坡沟水土流失的防控作用及其优化配置
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摘要
深化植被措施对坡沟系统水蚀过程的调控机理及其优化配置,成为土壤侵蚀研究关注的焦点问题。该研究以坡沟系统为研究对象,利用室内模拟降雨试验,结合三维激光扫描和微地貌分析技术,辨析了不同植被空间配置方式的水土保持功效,动力调控途径,提出了低覆盖度下调控侵蚀的植被优化配置。结果表明:从减水减沙的角度,不同位置的草带布设更具有直接拦沙的水土保持功效。水蚀动力的角度,草带对其坡面上方来水来沙和下方径流产沙的水蚀动力过程和侵蚀产沙过程分别发挥出缓流拦沙和滞流消能的水土保持功效,且这2种功效调控侵蚀的作用范围和作用强度与草带布设位置密切相关。草带位于坡面中下部,兼具较好的缓流拦沙和滞流消能的双重水土保持功效。依靠缓流拦沙的功效可以有效减缓坡面范围内的侵蚀强度;依靠滞流消能的功效能够有效减缓坡面下部和沟道范围内的侵蚀程度。植被在坡沟系统中的位置参数指标与侵蚀产沙量之间满足二次幂函数关系,该指标在0.571～1.200之间,为植被调控侵蚀最优布设区域。在此区域内布设植被,能够有效发挥出植被的双重水土保持功效。该研究有助于加深坡沟系统植被配置对土壤侵蚀产沙过程以及对水动力过程的作用机理的理解。
Understanding of the spatial configuration of vegetation regulated erosion and sediment transport of slope–gully systems is the key to manage erosion and sediment yield as well as to regulate the sediments in a watershed. A slope–gully system is the basic component of a watershed. Understanding the occurrence and development of erosion in slope–gully systems remains an essential problem in research related to the mechanisms of soil erosion dynamic, as well as the key to prevent soil and water loss in a watershed. Revealing the occurrence and development mechanism of the water erosion process in slope–gully systems, clarifying the regulation mechanisms of vegetation on the water erosion process in slope–gully systems, and proposing reasonable regulation and control modes have become the focuses of current studies on soil erosion. In this study, the slope-gully system was used as the object, using indoor simulated rainfall experiments combined with three-dimensional laser scanning technology and microtopography analysis technology. Such system discriminated the soil and water conservation function, dynamic regulation approach on water and sediment, and proposed the optimal vegetation pattern for regulation on the erosion at low vegetation coverage. The results showed that grass strips in different positions performed better in direct sediment interception function than performed in water storage function considering the water and sediment reduction. However, considering the water erosion dynamics, the grass strip could respectively exert runoff retardation sediment interception function on runoff and sediment from up-slope and exert runoff detention elimination energy function on runoff and sediment in the lower part during water erosion dynamic process and erosion sediment process. The regulation scope and strength of the two functions on water erosion dynamics were closely related to the configuration mode. When the grass strips were placed at the middle-lower part of the slope, they could play a better dual role in soil and water conservation functions. The erosion from the slope above the grass strip can be effectively mitigated by the effect of retarding runoff and intercepting sediment. In addition, the rapid increase in runoff velocity and "peak discharge" into the gully could be effectively weakened by the effect of retaining runoff and eliminating energy, thereby significantly reduced the sediment yield on the lower part of the slope and in the gully. A quadratic function could be used describe the relationship between the relative position of vegetation and sediment yield in the slope–gully system. The relative position indicator was between 0.571-1.200, which was the optimal regulation scope of vegetation on erosion. When grass strip was planted in the area, it could effectively exert both the best soil and water conservation effect of runoff retardation sediment interception function and runoff detention elimination energy function, and the regulation scope could extend each section from the slope to gully to achieve better effect of erosion reduction. The relative position indicators still need to be corrected and perfected based on experiments and observations. The information can be useful for better understanding the effect of vegetation on erosion sedimentation processes and hydrological processes in a slope-gully system.
Understanding of the spatial configuration of vegetation regulated erosion and sediment transport of slope–gully systems is the key to manage erosion and sediment yield as well as to regulate the sediments in a watershed. A slope–gully system is the basic component of a watershed. Understanding the occurrence and development of erosion in slope–gully systems remains an essential problem in research related to the mechanisms of soil erosion dynamic, as well as the key to prevent soil and water loss in a watershed. Revealing the occurrence and development mechanism of the water erosion process in slope–gully systems, clarifying the regulation mechanisms of vegetation on the water erosion process in slope–gully systems, and proposing reasonable regulation and control modes have become the focuses of current studies on soil erosion. In this study, the slope-gully system was used as the object, using indoor simulated rainfall experiments combined with three-dimensional laser scanning technology and microtopography analysis technology. Such system discriminated the soil and water conservation function, dynamic regulation approach on water and sediment, and proposed the optimal vegetation pattern for regulation on the erosion at low vegetation coverage. The results showed that grass strips in different positions performed better in direct sediment interception function than performed in water storage function considering the water and sediment reduction. However, considering the water erosion dynamics, the grass strip could respectively exert runoff retardation sediment interception function on runoff and sediment from up-slope and exert runoff detention elimination energy function on runoff and sediment in the lower part during water erosion dynamic process and erosion sediment process. The regulation scope and strength of the two functions on water erosion dynamics were closely related to the configuration mode. When the grass strips were placed at the middle-lower part of the slope, they could play a better dual role in soil and water conservation functions. The erosion from the slope above the grass strip can be effectively mitigated by the effect of retarding runoff and intercepting sediment. In addition, the rapid increase in runoff velocity and "peak discharge" into the gully could be effectively weakened by the effect of retaining runoff and eliminating energy, thereby significantly reduced the sediment yield on the lower part of the slope and in the gully. A quadratic function could be used describe the relationship between the relative position of vegetation and sediment yield in the slope–gully system. The relative position indicator was between 0.571-1.200, which was the optimal regulation scope of vegetation on erosion. When grass strip was planted in the area, it could effectively exert both the best soil and water conservation effect of runoff retardation sediment interception function and runoff detention elimination energy function, and the regulation scope could extend each section from the slope to gully to achieve better effect of erosion reduction. The relative position indicators still need to be corrected and perfected based on experiments and observations. The information can be useful for better understanding the effect of vegetation on erosion sedimentation processes and hydrological processes in a slope-gully system.
引文
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[16]Nearing M A, Simanton R, Norton D, et al. Soil erosion by surfacewaterflowonastony,semiaridhillslope[J].Earth Surface Processes and Landforms, 1999, 24(8):677-686.
[17]Shen H O, Zheng F L, Wen L L, et al. An experimental study ofrillerosionandmorphology[J].Geomorphology,2015,231:93-201.
[18]Vermang J, Norton L D, Huang C, et al. Characterization of soil surface roughness effects on runoff and soil erosion rates under simulated rainfall[J]. Soil Science Society of America Journal, 2015, 79(3):903-916.
[19]García-Ruiz J M. The effects of land uses on soil erosion in Spain:A review[J]. Catena, 2010, 81(1):1-11.
[20]Nadal-Romero E, Lasanta T,RegüésD, et al. Hydrological response and sediment production under different land cover inabandonedfarmlandfieldsinaMediterraneanmountain environment[J].BoletínddelaAsociacióndeGeógrafos Espa?oles, 2011, 201(55):303-323.
[21]BestAC.Thesizedistributionofraindrops[J].Quarterly Journal of the Royal Meteorological Society, 1950, 76(327):16-36.
[22]Zhang X, Yu G Q, Li Z B, et al. Experimental study on slope runofferosionandsedimentunderdifferentvegetation types[J]. Water Resources Management, 2014, 28(9):2415-2433.
[23]Zhou J, Fu B J, Gao G Y, et al. Effects of precipitation and restorationvegetationonsoilerosioninasemi-arid environmentintheLoessPlateau,China[J].Catena,2016,137(137):1-11.
[24]ReyF.Effectivenessofvegetationbarriersformarly sediment trapping[J]. Earth Surface Processes and Landforms,2004, 29(9):1161-1169.
[25]Li Grag, Abrahams A D, Atkinson J F. Correction factors in the determination of mean velocity of overland flow[J]. Earth surface Processes and Landforms, 1996, 21(6):509-515.
[26]Darboux F, Davy Ph, Gascuel-Odoux C, et al. Evolution of soil surface roughness and flowpath connectivity in overland flow experiments[J]. Catena, 2001, 46(2):125-139.
[27]于国强,李占斌,李鹏,等.坡沟系统水蚀过程调控措施的作用机理研究[M].北京:科学出版社,2017.
[28]宇涛,张霞,李占斌,等.不同草带覆盖位置条件下坡沟系统侵蚀产沙差异性[J].水土保持学报,2018,32(6):22-27.Yu Tao, Zhang Xia, Li Zhanbin, et al. Study on difference of erosionsedimentunderdifferentvegetationpattern[J].Journal of Soil and Water Conservation, 2018, 32(6):22-27.(in Chinese with English abstract)
[29]Jin K, Cornelis W M, GabrielsD, et al. Residue cover and rainfallintensityeffectsonrunoffsoilorganiccarbon losses[J]. Catena, 2009, 78(1):81-86.
[30]WangB,ZhangGH,ShiYY,etal.Soildetachmentby overland flow under differentvegetation restoration models in the Loess Plateau of China[J]. Catena, 2014, 116(5):51-59.
[31]WeiW,ChenL,FuB,etal.Theeffectoflandusesand rainfallregimesonrunoffandsoilerosioninthesemi-arid loess hilly area, China[J]. Journal of Hydrology, 2007, 335(3):247-258.
[2]García-RuizJM,Lana-Renault N,BegueriaS,etal.From plottoregionalscales:Interactionsofslopeandcatchment hydrologicalandgeomorphicprocessesintheSpanish Pyrenees[J]. Geomorphology, 2010, 120(3/4):248-257.
[3]Fu B J, Liu Y, LüY, et al. Assessing the soil erosion control serviceofecosystemschangeintheLoessPlateauof China[J]. Ecological Complexity, 2011, 8(4):284-293.
[4]Pan C Z, Shangguan Z P. The effects of ryegrass roots and shoots onloesserosionundersimulatedrainfall[J].Catena,2007, 70(3):350-355.
[5]Fu B J, Chen L, Ma K, et al. The relationships between land use and soil conditions in the hilly area of the Loess Plateau in northern Shanxi, China[J]. Catena, 2000, 39(1):69-78.
[6]Vásquez-MéndezR,Ventura-RamosE,OleschkoK,etal.Soil erosion and runoff in different vegetation patches from semiarid Central Mexico[J]. Catena, 2010, 80(3):162-169.
[7]Fu W, Huang M,GallichandJ, et al.Optimization of plant coverage in relation to water balance in the Loess Plateau of China[J]. Geoderma, 2012, 173-174:134-144.
[8]WeiW,ChenL,FuB,etal.Theeffectoflandusesand rainfallregimesonrunoffandsoilerosion inthesemi-arid loess hilly area, China[J]. Journal of Hydrology, 2007, 335(3):247-258.
[9]Antonello A, Maria A, Filomena C. Remote sensing and GIS toassesssoilerosionwithRUSLE3DandUSPEDatriver basin scale in southern Italy[J]. Catena, 2015, 131:174-185.
[10]Sun W Y, Shao Q Q, Liu J Y, et al. Assessing the effects of land use and topography on soil erosion on the Loess Plateau in China[J]. Catena, 2014, 121(121):151-163.
[11]Mohammad A G, Adam M A. The impact of vegetative cover type on runoff and soil erosion under different land uses[J].Catena, 2010, 81:97-103.
[12]XuGC,ZhangTG,LiZB,etal.Temporalandspatial characteristics of soil water content in diverse soil layers on landterracesoftheLoessPlateau,China[J].Catena,2017,158:20-29.
[13]Fattet M, Fu Y, Ghestem M, et al. Effects of vegetation type on soil resistance to erosion:Relationship between aggregate stability and shear strength[J]. Catena, 2011, 87(1):60-69.
[14]Curran J C, Hession W C. Vegetative impacts on hydraulics and sediment processes across the fluvial system[J]. Journal of Hydrology, 2013, 505(8):364-376.
[15]王龙生,蔡强国,蔡崇法,等.黄土坡面细沟形态变化及其与流速之间的关系[J].农业工程学报,2014,30(11):110-117.WangLongsheng,CaiQiangguo,CaiChongfa,et,al.Morphologicalchangesofrillonloessslopeandits relationshipwithflowvelocity[J].Transactionsofthe Chinese Society of Agricultural Engineering(Transactions of theCSAE),2014,30(11):110-117.(inChinesewith English abstract)
[16]Nearing M A, Simanton R, Norton D, et al. Soil erosion by surfacewaterflowonastony,semiaridhillslope[J].Earth Surface Processes and Landforms, 1999, 24(8):677-686.
[17]Shen H O, Zheng F L, Wen L L, et al. An experimental study ofrillerosionandmorphology[J].Geomorphology,2015,231:93-201.
[18]Vermang J, Norton L D, Huang C, et al. Characterization of soil surface roughness effects on runoff and soil erosion rates under simulated rainfall[J]. Soil Science Society of America Journal, 2015, 79(3):903-916.
[19]García-Ruiz J M. The effects of land uses on soil erosion in Spain:A review[J]. Catena, 2010, 81(1):1-11.
[20]Nadal-Romero E, Lasanta T,RegüésD, et al. Hydrological response and sediment production under different land cover inabandonedfarmlandfieldsinaMediterraneanmountain environment[J].BoletínddelaAsociacióndeGeógrafos Espa?oles, 2011, 201(55):303-323.
[21]BestAC.Thesizedistributionofraindrops[J].Quarterly Journal of the Royal Meteorological Society, 1950, 76(327):16-36.
[22]Zhang X, Yu G Q, Li Z B, et al. Experimental study on slope runofferosionandsedimentunderdifferentvegetation types[J]. Water Resources Management, 2014, 28(9):2415-2433.
[23]Zhou J, Fu B J, Gao G Y, et al. Effects of precipitation and restorationvegetationonsoilerosioninasemi-arid environmentintheLoessPlateau,China[J].Catena,2016,137(137):1-11.
[24]ReyF.Effectivenessofvegetationbarriersformarly sediment trapping[J]. Earth Surface Processes and Landforms,2004, 29(9):1161-1169.
[25]Li Grag, Abrahams A D, Atkinson J F. Correction factors in the determination of mean velocity of overland flow[J]. Earth surface Processes and Landforms, 1996, 21(6):509-515.
[26]Darboux F, Davy Ph, Gascuel-Odoux C, et al. Evolution of soil surface roughness and flowpath connectivity in overland flow experiments[J]. Catena, 2001, 46(2):125-139.
[27]于国强,李占斌,李鹏,等.坡沟系统水蚀过程调控措施的作用机理研究[M].北京:科学出版社,2017.
[28]宇涛,张霞,李占斌,等.不同草带覆盖位置条件下坡沟系统侵蚀产沙差异性[J].水土保持学报,2018,32(6):22-27.Yu Tao, Zhang Xia, Li Zhanbin, et al. Study on difference of erosionsedimentunderdifferentvegetationpattern[J].Journal of Soil and Water Conservation, 2018, 32(6):22-27.(in Chinese with English abstract)
[29]Jin K, Cornelis W M, GabrielsD, et al. Residue cover and rainfallintensityeffectsonrunoffsoilorganiccarbon losses[J]. Catena, 2009, 78(1):81-86.
[30]WangB,ZhangGH,ShiYY,etal.Soildetachmentby overland flow under differentvegetation restoration models in the Loess Plateau of China[J]. Catena, 2014, 116(5):51-59.
[31]WeiW,ChenL,FuB,etal.Theeffectoflandusesand rainfallregimesonrunoffandsoilerosioninthesemi-arid loess hilly area, China[J]. Journal of Hydrology, 2007, 335(3):247-258.