effects of rainfall intensity, underlying surface and slope gradient on soil infiltration

Upload: satria11

Post on 02-Jun-2018

213 views

Category:

Documents


0 download

TRANSCRIPT

  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    1/10

    Effects of rainfall intensity, underlying surface and slope gradient on soil inltrationunder simulated rainfall experiments

    Jun Huang, Pute Wu , Xining ZhaoCollege of Water Resources and Architecture Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China

    Institute of Water Saving Agriculture in Arid regions of China, Northwest A&F University, Yangling, 712100, Shaanxi, China

    National Engineering Research Center for Water Saving Irrigation at Yangling, Yangling, 712100, Shaanxi, China

    Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling, 712100, Shaanxi, China

    a b s t r a c ta r t i c l e i n f o

    Article history:

    Received 15 February 2012Received in revised form 14 September 2012Accepted 22 October 2012Available online xxxx

    Keywords:

    Simulated rainInltrationVegetationRecharge coefcient

    Knowledge of inltration patterns and process is very important in understanding and managing slopehydrological processes, crop irrigation, soil erosion, and so on. This paper describes a study in which simulat-ed rainfall events were used to study the effects of various factors (vegetation cover, rainfall intensity, andslope angle) on the soil moisture increase after rainfall and the inltration recharge coefcient. Soils hostingthree different plants (purple medic, PM; spring wheat, SW; and ryegrass, RS) were considered, along withbare soil (BL). These soil surfaces were tested with four different slopes (8.8, 17.6, 26.8 and 36.4%) andsubjected to ve different rainfall intensities (0.5, 0.75, 1.0, 1.5 and 2.0 mm min1). The following key resultswere obtained: (1) The water distribution in BL boxes differed signicantly from that in boxes with vegeta-tion cover, but all boxes with vegetation cover exhibited similar distributions. Vegetation cover signicantlyincreased the depth of the wetting front: under very similar conditions, the wetting front in the RS boxreached a depth of more than 35 cm, while that in the BL box reached only 25 cm. (2) Vegetation cover(especially ryegrass) yielded a greater soil moisture increase than did bare land. The overall average soilmoisture increase for RS boxes was 36.7 5.1 mm, about twice than that of BL. (3) The water storage afterrain across the whole soil prole initially increased and then decreased as the rainfall intensity rose. No

    differences in the average soil water content increase were found between various rainfall intensities.(4) As the slope increased from 8.8% to 36.4%, the water storage increase initially rose but then fell sharply.There were signicant differences (p=0.05) between the water storage increases for gradual slopes (8.8and 17.6%) and steep slopes (26.8 and 3.4%). (5) The recharge coefcient increased with increasing vegeta-tion cover but decreased with increasing rainfall intensity, slope gradient, and initial soil water content.The average value for boxes with vegetation cover was 1.5 times that for BL boxes. The vegetation coverwas the most important factor in determining the recharge coefcient.

    2012 Elsevier B.V. All rights reserved.

    1. Introduction

    Arid and semiarid regions cover a large proportion of global landsurface area (Arnon, 1972; Dregne, 1991). In these areas, soil mois-ture is the greatest limitation affecting vegetation restoration andcrop production (Chen et al., 2007; Moreno-de las Heras et al.,2011), especially, in the Chinese Loess Plateau (Fu et al., 2003; Wuet al., 2003). The amount of water inltrating the soil surface has adirect effect on the quantity of surface runoff and erosion, and therecharge of both soil and ground water (Liu et al., 2011). Inltration isthe process whereby water enters the soil and adds to the total soil

    moisture (Philip, 1957a; Lei et al., 1988). It is therefore an importantfactor in determining the soil moisture level (Bouwer, 1986; Hillel,1998; Shao, 1985). There are a number of factors that affect inltration,including the slope, rainfall regime, soil texture, soil structure, vegeta-tion, and so on (Leonard and Andrieux, 1998). Moreover the effects ofthese factors are often interdependent. Because it is quite difcult toinvestigate multiple factors at once when studying soil inltration,most previous studies have focused on only oneor twoof them. Howev-er, it is important to understand multi-factor effects on inltrationpatterns and processes in order to properly understand and predictthe impact of re-vegetation and cultivation, especially in light of theirinuence on soil moisture in regions where rainfall is the sole sourceof water replenishment (Wang et al., 2008).

    Soil inltration is highly dependent on rainfall intensity and therelationship between these two quantities has been studied in detail(Assouline and Mualem, 1997; Foley and Silburn, 2002; Hawke etal., 2006; Morin and Benyamini, 1977).McIntyre (1958)discovered

    Catena xxx (2012) xxxxxx

    Corresponding author at: Institute of Soiland Water Conservation, Chinese Academyof Sciences& Ministryof Water Resources,Yangling,712100, Shaanxi,China. Tel./fax:+ 8629 87011354.

    E-mail addresses:[email protected](J. Huang),[email protected](P. Wu),[email protected](X. Zhao).

    CATENA-01880; No of Pages 10

    0341-8162/$ see front matter 2012 Elsevier B.V. All rights reserved.

    http://dx.doi.org/10.1016/j.catena.2012.10.013

    Contents lists available at SciVerse ScienceDirect

    Catena

    j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c a t e n a

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013mailto:[email protected]://dx.doi.org/10.1016/j.catena.2012.10.013http://www.sciencedirect.com/science/journal/03418162http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013http://www.sciencedirect.com/science/journal/03418162http://dx.doi.org/10.1016/j.catena.2012.10.013mailto:[email protected]://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    2/10

    that the permeability of the skin seal (crust) is 2000 times lower thanthat of the underlying soil layers.Morin and Benyamini (1977)stud-ied the rate of inltration through bare and mulched soil under differ-ent rainfall intensities and concluded that the inltration rate is afunction of the accumulated rainfall depth and is signicantlyaffected by the impact of raindrops. Beven and Germann (1982)found that raindrop impacts can seal the soil, signicantly reducingthe rate of inltration.Rmkens et al. (1985)reported that rainfall

    drops can destroy or deform the arrangement of soil particles andthat the detached particles can clog the soil pores, again reducingthe rateof inltration. Assoulineand Mualem (1997) modeled sealingdue to rainfall as a function of rainfall intensity, the second momentof the drop-size density distribution, the maximal drop diameter,the compaction limit of the soil, and the soil's initial shear strength,which depends on the initial soil bulk density and water content.Abu-Awwad (1997)studied the inuence of surface crusts on waterinltration and redistribution, and found that sand columns couldsignicantly increase the amount of moisture stored in the soil andreduce the amount of runoff.Fohrer et al. (1999)conducted a seriesof laboratory experiments to study changes in the rate of inltrationand soil surface contention under continuous/subsequent rainfalland found that subsequent rainfall resulted in a much more rapiddecrease in the rate of inltration than did continuous rainfall. Inter-estingly,Foley and Silburn (2002)showed that the rate of inltrationincreased in parallel with the rainfall intensity, which appears to con-tradict previous ndings.Li and Shao (2006)studied the inuence ofrainfall intensity on inltration and redistribution, and identiedpower function relations between the position of the wetting front,the rainfall duration, and the rainfall intensity. Laboratory experimentshave also been conducted to investigate near-surface soil hydrologicconductivity under different rainfall intensities (Hawke et al., 2006).They found thatrainfall intensityhad an important inuence on soil hy-draulic conductivity. Schindewolf and Schmidt (2012)showed that thecumulative rainfall had the negative effect on soil inltration, using a31 m plot with a runoff-feeding device which was installed at theupper end of the plot under simulated rainfall events.

    The importance of vegetation cover in maintaining and improving

    soil stability and permeability is well known and has been discussedextensively (Branson et al., 1972; Coleman, 1953). Vegetation coveraffects soil inltration in two ways: (1) by changing the hydrologicalprocess of rainfall-inltration on slopes, and (2) by modifying thestructure of the soil pore spaces as a result of the formation of theroot system (Li et al., 1992; Yun et al., 2006). Field investigationsconducted by Marston (1952) in the Davis County ExperimentalWatershed demonstrated that vegetation cover of 65% or more signif-icantly reduced runoff and increased inltration.Galle et al. (1999)studied the water balance in a belt-shaped vegetation pattern inwestern Niger and created a simple water balance model to predictsoil inltration based on four years eld observations.McLeod et al.(2006)researched the soil water regimes of a Brown Chromosol onthe Northern Tablelands of NSW, Australia under three pasture types,

    and noted that the vigorous phalaris plus white clover pasture yieldedthe greatest potential for water storage. Wang et al. (2008)studiedthe inuence of vegetation on inltration and redistribution patternswith the aim of identifying tools for rebuilding desert ecosystems andsuggested that vegetationhad a signicant effect on inltration and re-distribution patterns in stabilized sand dunes. Schwartz et al.(2010)studied soil water redistribution under sweep tillage and in untilledcontrol plots and found that tillage with a sweep of 0.070.1 m signi-cantly reduced net waterstorage at soil depths above0.3 m but did notaffect the water content at depths 0.2 m. The effect of rock fragmentcover on soil inltration rate under Mediterranean conditions waswidely investigated (Agassi and Levy, 1991; Martnez-Murillo et al.,2012; Ruiz-Sinoga and Martnez-Murillo, 2009). They found that rockfragment cover could signicantly increase inltration and decrease

    evaporation.

    At present, there is no strong consensus in the literature regardingthe effects of the slope's gradient on soil inltration, although a num-ber ofeld and experimental simulated words have been conducted.Some workers have claimed that steeper gradients have a positiveinuence on inltration.Poesen (1986)studied ve different slopeangles and found that steeper gradients yielded reduced sealingbecause the raindrops hit the soil on steeper slopes at a more acuteangle with less kinetic energy per unit surface area. Janeau et al.

    (2003)also studied the in

    uence of the slope on in

    ltration undereld conditions, examining gradients ranging from 16 to 63%. Theirresults indicated that the steadynal inltration rate increased sharplywiththe gradient. However, othershave reported decreasedinltrationwith increasing slope angle due to a decrease in the depth of the over-land ow and reduced surface storage (Chaplot and Le Bissonnais,2000).Nassif (1975)reported that inltration capacity decreased asthe slope increased in laboratory experiments. Similar ndings werereported byJiang and Huang (1984),Jin et al. (1995)andYuan et al.(2001). Interestingly,Fu et al. (2008)found that the nature of the rela-tionship betweenthe slope gradient and inltrationchanged as thegra-dient increased, as did the likelihood of soil crust formation. Moreover,some other authors found that there is no relation between soil inltra-tion and gradients (Cerd and Garca-Fayos, 1997; Mah et al., 1992;Singer and Blackard, 1982).

    While there have been many reported studies on soil inltration,there is a need for more detailed investigations of multi-factor effectson inltration and soil moisture levels. To this end, we conducted aquantitative study on soil inltration and the factors that control itusing simulated outdoor rainfall events on a range of slope anglesand underlying surfaces. The objective of the study was to better un-derstand the differences between bare and vegetation-covered slopesin terms of (1) the position of the wetting front; (2) soil moisturestorage after rain; and (3) the variation of the recharge coefcient.

    2. Materials and methods

    2.1. Site description

    The experiments were conducted at the eld monitoring stationoperated by the Soil and Water Conservation Research Institute of theChinese Academy in Linghou, Wuquan Town, Yangling District, ShaanxiProvince. The Yangling District is located on the western GuanzhongPlain of Shaanxi Province, north of the Weihe River (E1075910808,N34143420). It is 7 km long from north to south and 16 km widefrom east to west, covering a total area of 94 km 2. The elevation of thedistrict is greatest at the northern end and falls gradually on movingsouthwards, from 540.1 m ASL to 418.0 m. There are three rivers on itsborders: the Weihe River, which runs along its southern border, andtwo smaller rivers that run along its eastern and northern borders, re-spectively. The district is spread over the terraces and the rst, second,and third oodplains of the Weihe, with the town of Wuquan lying thethird oodplain. The area has an arid-humid monsoon climate. The an-nual mean precipitation and evapotranspiration are 637.6 mm and884.0 mm, respectively.

    2.2. Rainfall simulator

    All experiments were performed with a portable needle rainfallsimulator as depicted in Fig. 1. Portable rainfall simulators of thiskind have been widely used for various purposes (Walsh et al., 1998)because they make it possible to gather data under controlled condi-tions over relatively short periodsof time (Navas et al., 1990). The rain-fall simulator has four components: (1) The Mariotte bottle, whichprovides a constant water level in the water tank to guarantee highrainfall uniformity. (2) The vibration motor, which produces a uniform

    distribution of raindrops across the catchment. (3) The needle plate.

    2 J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    3/10

    (4) The water tank, which has a volume of 1.7 m 1.2 m 0.25 m. For adetailed description of the rainfall simulator, seeTable 1.

    2.3. Soil box setup

    Most plot areas were less than 5 m2 used for simulated rainfall ex-periments since 1938 (Iserloh et al., 2010). In general, the soil box/plot size for lab-experiments were L W D= (12 m)(0.51 m)(0.220.5 m) (Adekalu et al., 2007; Dunj et al., 2004; Fohrer et al.,

    1999; Kato et al., 2009; Molina et al., 2007; Nassif, 1975; Pan andShangguan, 2006; Poesen et al., 1994; Poulenard et al., 2001; Vahabiand Nikkami, 2008). So, we set the soil boxes as 1.2 m0.8 m0.45 m. They were tted with four wheels to facilitate transportationand with a jack to allow their slope to be adjusted from 0 to 57.7%.The boxes had apertures at the bottom to allow free movement of soilwater.

    The clay content of the soil in Linghou, Wuquan Town, which is lo-cated on the third oodplain and terrace of the Weihe River is veryhigh; while the soil in the Yangling Water Saving Exhibition Garden,which is located on the rst oodplain and terrace of the WeiheRiver, is rich in sand particles. Both of them are quite different fromthat generally found on the Loess Plateau of our object of study. Inorder to get a similar texture soil with that generally found on the

    Loess Plateau, these two soils from these two sites were blended toyield a 1:1 w/w mixture that was gently crushed, passed through a10 mm sieve, and then air-dried to give an initial water content of610%. Finally, the sieved and dried soil was thoroughly mixed tominimize differences between treatments and packed into theboxes in four 10 cm layers to achieve a natural bulk density of around1.35 g cm3. Each layer of soil was lightly raked before packing thenext later to minimize the discontinuities between layers. Variouschemical and physical properties of the nal experimental soil areshown inTable 2.

    2.4. Treatments

    Five different rainfall intensities were employed in combinationwith four different slopes. The studied rainfall intensities were 0.5,0.75, 1.0, 1.5 and 2.0 mm min1; the studied slopes were 8.8%,17.6%, 26.8% and 36.4%. Three vegetation types were considered: rye-grass (Lolium perenne L), purple medic (Medicago sativa Linn) andspring wheat (Triticum aestivum), which are widely grown acrossthe Loess Plateau. Unplanted bare soil was also tested as a controltreatment, giving four underlying surface types: purple medic (PM),spring wheat (SW), ryegrass (RS) and the bare land control treatment(BL). Grazing grass and crops were sowed separately, using broadcastsowing; grass was sowed in early April of 2009 and crops in mid-March of 2009. Ryegrass and purple medic were mowed between 2and 5 times during the experiment, according to local managementpractices. The experiment began in mid-May 2009. In order to moni-tor the development of rooting depth during the whole experiment,we measured the maximum root length for three vegetations at 5th,

    June and 11th, August, 2009, respectively. The data are illustrated inFig. 2. During the whole detecting period, the root length of Purplemedic was the longest. But the root tillering of ryegrass was thelargest.

    2.5. Measurements and methods

    The runoff amount was measured using a 1000 ml standard cylin-

    der every 0.5

    20 min after runoff generation. After the deposition

    Aeration pipe

    Water inlet

    Mariotte

    flask of

    watering

    device

    Intake pipe

    Triangle

    bracket

    Four-legged bracket

    Water tank

    Needles plate

    Vibration motor

    Soilbox

    Height regulation bolt

    Fig. 1.The rainfall simulator and its components. (See Fig. 1 with PDF format).

    Table 1

    Technical details of the rainfall simulator.

    Technical conguration Parameter values

    Area 1.5 m1.0 mNeedles number Around 650Water supply Water level controlRainfall intensity 0.5, 0.75, 1.0, 1.5 and 2.0 mm min1

    Mean coefcient of uniformity > 80%Height of fall 1.2 mInside diameter 1 mmSpace between needles 40 mmDrop range 0.52 mmMean drop velocity 4.78 m s1

    Mean rainfall kinetic per unit area and time 0.2193 J m2 s1

    3J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    4/10

  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    5/10

    size. Studies ofAbu-Awwad (1997),Wang et al. (2008)andBao et al.(2012) revealed that soil moisture redistribution mainly occurred inthe depth of 020 cm, and there were no signicant changes in soilmoisture for layer of lower than 20 cm after rain.

    3.2. Soil water proles following the termination of rainfall.

    Fig. 5shows the average increase in soil moisture at differentdepths for four underlying surfaces with a slope angle of 8.8% afterapproximately 42 mm of rainfall. It is apparent that there were onlymodest differences between the different surfaces in terms of the in-crease in soil moisture for the 010 cm layer. However, in the deeperlayers, the increase in soil moisture was much more pronounced inthe boxes with vegetation cover than in the BL boxes. The average in-crease in soil moisture over the full depth of the box (i.e. between0 and 40 cm), the start time of runoff, and the runoff volume foreach surface type is shown inTable 3. We can see that vegetationsignicantly postponed runoff generation (Regs et al., 2010) and

    diminished the runoff amount. No differences in the start time of run-off were detected between four underlying surface boxes (p>0.05).There were signicant differences in the runoff volume (p= 0.05) be-tween vegetated-boxes and bare soil, but no differences between

    boxes with vegetation cover (p> 0.05). The observed increases arerather modest compared to those reported in some earlier eldstudies (Abu-Awwad, 1997; McLeod et al., 2006; Wang et al., 2008)due to boundary effects, since our soil boxes were relatively small.Many comparative studies reveal that the scale of plot has the signif-icant effect on slope runoff/inltration (Boers and Ben-Asher, 1982;Schindewolf and Schmidt, 2012; Smets et al., 2008a). It was notewor-thy that the ASMI for the 010 cm layer of the PM boxes was similarto that for the BL boxes. During the experiment, we found that a layerof ashy green biological crust was formed in the surface of the PMboxes, which reduced the roughness of the slope to some extent,increasing the amount of runoff and decreasing inltration (Bond,1964; Eldridge et al., 2000). But we did not identify the biologicalcrusts due to the limitation of equipment. The average soil moistureincrease for each layer decreased as the depth increased, especiallyin BL boxes. For the 010 cm surface layer in BL boxes, the averagesoil moisture increase was around 10 mm. Conversely, that for the1020 cm layer was 4.4 mm, i.e. approximately 56% lower, and theincrease for the 2040 cm later was only 2.8 mm. The ASMI thus

    decreased exponentially with the depth in the BL boxes. The moistureincrease also declined with depth in the boxes with vegetation cover,but the decrease was much less pronounced than in the BL boxes.Many led observations (Hu et al., 2006; Xu et al., 2003) revealedthat the soil moisture for upslope was smaller than that for downslope,

    45cm

    Soil surface

    Soil bottom

    5 cm

    15 cm

    25 cm

    35 cm

    Adjustable leg

    Width:80 cm

    Length:200cm

    Height:45 cm

    Up slope

    Down slope

    Runoff collector

    Soilsurfa

    ce

    Soilbotto

    m

    Fig. 3.Schematic diagram showing the apparatus used to measure soil moisture. Note: The red circles indicate where soil samples were taken to determine the soil moisture level.(For interpretation of the references to color in this gure legend, the reader is referred to the web of this article.)

    Fig. 4.Soil moisture redistribution in test cases A and B. Curves a and b indicate the soilmoisture content at different depths before and immediately after the termination ofrainfall, respectively; lines c, d and e indicate the inltration of soil moisture 4, 8 and

    21 h after the termination of rainfall.

    Fig. 5.Average soil moisture increment (ASMI) for each layer and slope position at the

    end of rainfall for four underlying surfaces.

    5J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    6/10

    and there was a signicant difference between them. However, no dif-ferences were found between upslope and downslope sampling sites(p=0.582) in these experiments, which might be due to the relativelyshort slope length. The only underlying surfaces between which therewas a signicant difference in soil moisture increase were BL and RS(p=0.05). Overall, our ndings indicate that vegetation can increasesoil moisture retention after rain at least somewhat compared to bareland, in other word, vegetation improve soil water storage to some ex-tent(Liu et al., 2000). This is likely to be important in arid and semi-aridregions.

    The histogram in Fig. 6 shows the soil moisture increases forve different rainfall intensities for a given total rainfall (approx.54 mm) with a slope gradient of 17.6% in RS boxes. It is clear thatthe relationship between rainfall intensity and the soil moistureincrease is complex and irregular; the ASMI for the different soillayers and positions differed without any clear trend or pattern. Forthe 010 cm surface layer, the soil moisture increase initially in-creased with the rainfall intensity but then decreased, peaking ataround 1.0 mm min1. However, for the layers between 10 and40 cm, the soil moisture increase decreased uniformly with increas-ing rainfall intensity. Higher rainfall intensities yield raindrops with

    more kinetic energy, which has two consequences that increase theamount of runoff and disfavor inltration. First, it destroys the struc-ture of the topsoil, decreases soil permeability, and increases thesplash erosion (Schmidt, 2010). Second, raindrop impacts might inducesome extent of soil sealing, preventing inltration (Abu-Awwad, 1997;McIntyre, 1958).Table4 summarizes theaverage increase insoil moisture

    content between 0 and 40 cm, the start time of runoff and the runoffvolume for ve different rainfall intensities with a constant amount ofrainfall. The start time of runoff and runoff volume decreased and in-creased with increasing rainfall intensity (eg. Martnez-Murillo et al.,2012). Regression analyses were conducted to study the relationshipbetween rainfall intensity (ri) and the total soil moisture increase for the040 cm soil layer (SW040 cm). The obtained tting equation wasSW040 cm=9.6ri

    2 +15.2ri+28.5 (r= 0.9315, F =6.553, p= 0.1324).This further conrmsthat increases in rainfall intensity are not conduciveto soil inltrationand may reduce the amount of inltration(eg. Fraser etal.,1999;Huang et al.,2010;Wischmeieand Smith,1978).ANOVAdidnotidentify any signicant differences between the different rainfall intensi-ties in terms of the average soil moisture increase (P> 0.05). But signi-cant differences were found in the start time of runoff and runoffvolume in these experiments (p= 0.05).

    For modest slopes, increases in the steepness of the slop gavehigher soil moisture increases. However, as the slopes became steep-er still, this relationship reversed. The overall soil moisture increasesat depths of 040 cm for four gradients in SW boxes with rainfall in-tensities of 0.751.0 mm min1 are shown inFig. 7and Table 5. Agradient of 17.6% was most favorable for soil inltration; similar nd-ings have been reported previously (Fu et al., 2008; Huang et al.,

    2010). The soil moisture increases for slopes of 8.8% and 17.6% slopewere more than twice as large as those for slopes of 26.8% and36.4%. The data of the soil moisture changes at depths of 040 cm re-vealed that soil permeability increasedrstly and reduced afterwardwith increasing gradient. Because more depositional crusts mightoccur on gentler slopes (Valentin, 1991), resulting in decreasing soilinltration. However, much runoff volume occurring on the steeper

    Table 3

    The average soil moisture increase at depths of 040 cm for four underlying surfaces.

    Underlying surfaces

    BL PM SW RS

    Average increase in soilmoisture at depths of040 cm/mm

    17.63.7a 31.83.6ab 32.74.9ab 36.75.1b

    Mean rainfall amount/mm 42.09.1a 42.38.0a 43.06.8a 41.79.5aStart time of runoff/min 4.55.1a 5.04.3a 5.54.6a 9.96.3aRunoff volume/l 18.6 7.0a 10.1 5.2b 9.5 3.5b 8.2 4.1bNumber of rainfall events 9 8 5 7

    Note: Meanstandard deviation within a row followed by the same letter are notsignicantly different at p=0.05 level using the least signicant difference (LSD)method. The same as below.

    Fig. 6.ASMI for each layer and slope position after the termination of rainfall for ve

    rainfall intensities.

    Table 4

    The average soil moisture increase at depths of 040 cm for ve rainfall intensities.

    Rainfall intensity/mm min1

    0.5 0.75 1.0 1.5 2.0

    Average increase in soil moisture atdepths of 040 cm/mm

    32.31.7a

    35.32.3a

    36.82.9a

    26.52.8a

    21.63.1a

    Mean rainfall amount/mm 55.33.9a

    53.52.0a

    54.82.3a

    54.81.5a

    53.01.6a

    Start time of runoff/min 17.0 6.9ab

    14.34.9b

    9.65.3abc

    5.54.1ac

    4.23.9c

    Runoff volume/l 10.33.4a

    13.73.3ac

    14.13.1bc

    15.45.0d

    18.64.6d

    Number of rainfall events 11 14 15 8 10

    Fig. 7.ASMI for each layer and slope position at the end of rainfall for four slope angles.

    6 J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    7/10

    gradient destroys the crusts and therefore favors greater inltration(Poesen, 1986). Janeau et al. (2003) also revealed this conclusionbased on 15 eld runoff plots. The start time of runoff decreasedwith increasing gradient in this study, which is opposite to the resultsofMartnez-Murillo et al. (2012). The soil moisture increase, the starttime of runoff and runoff volume for the 8.8% slope differed signi-cantly from those for the 26.8% and 36.4% slopes, as did that for the17.6% slope (p =0.05).

    3.3. Recharge coefcient

    The recharge coefcient denotes the percentage of the total rain-fall that ends up as inltration water. It thus provides a measure ofthe efciency of rainfall-inltration and also indirectly describes theproportion of the rainfall that is lost as runoff (Li and Shao, 2007b).The recharge coefcient is therefore an important parameter for un-derstanding the relationships between rainfall, runoff and inltration.If we letri,G,tandqrepresent rainfall intensity, slope gradient, rain-fall duration and total runoff amount, and assume that evaporationduring rainfall is negligible, the recharge coefcient (Rc) can beobtained by the following equation:

    Rc ritcosGq =ritcosG 1q=ritcosG 2

    When the rainfall is under manual control, riand tcan be heldconstant. Under such circumstances, the inltration recharge coef-cient is highly dependent on the rate or amount of inltration. Wecalculated the inltration recharge coefcient for 80 rainfall events;

    the mean values for different underlying surfaces are plotted inFig. 8. The smallest recharge coefcients were observed in BL boxes,uctuating between 19.5 and 95.8% with a mean value of 54.9%.This indicates that most of the rain that fell on the BL boxes endedup as runoff. Boxes with vegetation cover had greater recharge coef-cients than BL boxes, with an average value of 78.0%. More timewas needed to form a stable runoff ow in boxes with vegetation,which increased the time during which inltration could occur. Fur-

    thermore, roots in soil formed different sizes of non-capillary pores(especially Ryegrass, which produced quantities of roots), whichwould be expected to increase the rate of inltration to some degree(Li et al., 1992; Wang et al., 2005; Yun et al., 2006). The rechargecoefcients for PM boxes, SW boxes and RS boxes uctuated between57.9 and 98.3%, 60.9 and 94.3% and 56.1 and 97.1%, respectively,which is largely consistent with the results ofFu et al. (2008), whoinvestigated untilled elds using simulated rainfall. Variance analysisshowed that there were signicant differences (p=0.05) in the re-charge coefcients for BL boxes and vegetated-boxes, but no differ-ences among boxes with vegetation cover.

    The rainfall intensity, vegetation cover, slope, initial soil moisture,and other factors are all likely to affect the inltration recharge coef-cient. In order to conveniently compare the inuence of each factoron the recharge coefcient and minimize the error caused by differ-ences in dimensions between parameters, the raw data were stan-dardized according to formula(3).

    Xi xixmin = xmaxxmin 3

    whereXi,xi,xmaxand xminwere the standardized data, the raw data,the maximum value ofxiand minimum value ofxi, respectively.

    Regression analyses of these standardized data were conducted,yielding the relationship between the recharge coefcient and thefour factors shown in Eq.(4).

    Rc 0:5010:518ri 0:693cv0:207G0:259asm 4

    Here,Rc,ri,cv,Gandasmdenote the recharge coefcient (%), rain-

    fall intensity (mm min1), vegetation cover (%), slope gradient (%)and initial soil moisture (%), respectively. The model's high multiplecorrelation coefcient, r=0.867 (pb0.001), indicates that it has ahigh predictive capability (Table 6). All regression coefcientsreached a signicant level (Table 7). In addition, the variance inationfactors for the independent variables were far less than 10, indicatingthat there were no collinearity problems with the independent vari-ables, which further suggests that the tting model is reasonableand feasible.

    Eq. (4)indicates that the recharge coefcient decreases as therainfall intensity, slope gradient, and initial soil moisture increase,and that it increases with increasing vegetation cover. Increasingthe rainfall intensity would destroy the structure of the topsoil andform soil seals (Abu-Awwad, 1997; Chen and Cai, 1990; McIntyre,

    1958; Schmidt, 2010), which could reduce hydraulic conductivity(Hawke et al, 2006) and increase the runoff volume. Higher levelsof initial soil moisture would decrease the soil water potential andwater suction (Hawke et al, 2006; Philip, 1957b; Weigert andSchmidt, 2005), which is not conducive to soil inltration. Vegetationchanges the rainfall transformation process due to effects such as

    Table 5

    The average soil moisture increase at depths of 040 cm for four slope angles.

    Slope angles

    8.8% 17.6% 26.8% 36.4%

    Average increase in soil moisture at depthsof 040 cm/mm

    31.05.6a

    41.37.2a

    16.82.1b

    17.92.0b

    Mean rainfall amount/mm 45.7 9.1a

    46.79.3a

    45.79.0a

    45.49.4a

    Start time of runoff/min 12.8 4.8a

    15.64.8a

    6.33.9b

    5.85.0b

    Runoff volume/l 12.66.4a

    8.45.0a

    17.24.2b

    21.74.6b

    Number of rainfall events 11 12 19 19

    Fig. 8.Recharge coefcients for different underlying surfaces. Note: The same letter isnot signicantly different at p =0.05 level using the least signicant difference (LSD)

    method.

    Table 6

    Variance data for tting Eq.(4).

    DF SS MS F p

    Regression 4 1.420 0.355 17.428 0.000Residual 15 0.306 0.020Total 19 1.726 0.091

    7J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    8/10

    plant interception and retention (Llorens and Domingo, 2007). In ad-dition, the destruction of raindrop on the topsoil was diminished byvegetation. All the above may reduce the runoff volume and providesmore opportunities for water inltration. A comparison of the abso-lute values of the regression coefcients in Eq.(4)suggests that themost important factor in determining the recharge coefcient is thevegetation cover (Kato et al., 2009; Molina et al., 2007), followed bythe rainfall intensity and the initial soil moisture, with the slopebeing the least important. However, eld studies fromChen et al.(2011)concluded that slope gradient is as important as rainfall inten-sity and vegetation cover-and it may be more important than othertwo factors. This difference may be caused by the distinct conditionbetween simulated experiments at small scale and the eld study.Moreover, different growth periods of vegetation also exhibited var-ied inuence on slope runoff and inltration (Wu and Zhang, 2006).So the effect of slope gradient, vegetation cover and scale effect onslope runoff/inltration needs to further study.

    This experiment was conducted using the disturbed soil and underspecic conditions, which is a qualitative simulated study. Therefore,it may be difcult to transfer the results of this study to the eld dueto the effect of the specic experimental conditions on the results(Assouline and Ben-Hur, 2006; Romero et al., 2007). The total runoffcoefcient of this experiment was 27.3%17.1% with greater varia-tion, which was much larger than the value fromWei et al. (2007),but close to the results fromJaneau et al. (2003). The steady nalinltration of this experiment ranging from 0.0237 mm min1 to1.6793 mm min1 was close to the results fromJaneau et al. (2003),

    while slightly smaller than the results from Kato et al. (2009). Themean inltration rate of this study was larger twofold than that fromMartnez-Murillo et al. (2012).Molina et al. (2007)studied the effectof vegetation cover and land use on runoff generation in Andean hillyslope, and their results about runoff coefcient and time to runoff forbare/degraded land were similar with that of our studies, but forvegetated-lands or rangelands were very different. They also foundthat runoff generation is mainly controlled by the surface vegetationcover and land management.

    Bubenzer (1979)divided rainfall simulators into two types basedon compiling an inventory of 63 rainfall simulators that have beenused by researchers in recent years: (1) the drop former simulator(Adams et al., 1957; Black, 1972); and (2) the nozzle type simulator(Hart, 1984; Meyer, 1979; Pall et al., 1983; Schindewolf and

    Schmidt, 2012). Drop former simulators are mainly used on smallplot studies of inltration and soil splash. Nozzle type simulatorsare used on both large and small plot studies. In this study, we useda needle type simulator to simulate the natural rainfall intensity andamount for studying soil inltration under different underlying sur-faces. The mean fall velocity and drop diameter are 4.78 m s1 and0.52 mm, respectively, which are close to that from the studies ofSchindewolf and Schmidt (2012). However, there must be somedifference on rainfall characteristics (such as the drop diameter, fallvelocity and rainfall kinetic) between the natural rainfall and ourrainfall simulator, which was also conrmed byZhou et al. (1981).Splash erosion may be the main water erosion in these experimentsbecause of the small size of soil boxes and the needle type rainfallsimulator (Martnez-Murillo et al., 2012; Morgan, 2005; Schmidt,

    2000), which signicantly differed from the monsunal runoff plot and

    the natural rainfall.Alves Sobrinho et al. (2008)andSchindewolf andSchmidt (2012)installed a runoff-feeding device at the upper end ofthe runoff plot to increase the energy momentum of surface runoffand simulate the eld monsunal plot, and obtained the desired results.Vegetation can absorb raindrop kinetic energy (Greene and Hairsine,2004; Gyssels et al., 2005; Luce, 1997) to signicantly reduce theamount of splash erosion, especially in small scale runoff plots. Our re-sults showed that the treatment of PM, SW and RS were signicantly

    decreased the sediment yield compared to the bare soil treatment.Zheng et al. (2007) conrmed that the effect of vegetation on thesediment-reduction rate in the small plot was larger than that in themonsunal research area.

    Previous studies (Blschl and Sivapalan, 1995; Boers and Ben-Asher,1982; Li et al., 2005; Parsons et al., 2006; Poesenet al., 1994; SchindewolfandSchmidt,2012;Smetset al., 2008a) concludedthat the plot scale hasa dramatic effect on runoff/inltration measurement. This hasbeen con-rmed byPanini et al. (1997)andGmez and Nearing (2005). The vari-ation of runoff production andsoil inltration increased with decreasingplot areas (Raclot et al., 2009; Smets et al., 2008b).Puigdefbregas et al.(1998)andDe Giesen et al. (2011)noted that the opportunity for inl-tration increased with slope length increasing and more water mightenter into soil. Moreover, the soil depth also has an important effect onsoil inltration and redistribution. Generally, the depth of detecting thesoil inltration or wet front in the eld condition was generally about2.0 m (McLeod et al., 2006; Wang et al., 2008), and this might makemore sense. But, like most lab-experiments, it was impossible to achievefor this study due to the xed depth of soil boxes. Therefore, the resultsof this study are difcult to extrapolate data about runoff/inltration tolarger scale. Nevertheless, the results of this study also could be usedfor comparative purposes and provide some useful information for bet-ter understanding the difference between bare and vegetation-coveredslopes in term of soil inltration and water redistribution.

    4. Conclusions

    Vegetation can improve soil permeability and soil water storageafter rain. Our results showed that there are slight differences in

    water storage between BL boxes and boxes with vegetation cover atsoil depths of 010 cm. However, the difference becomes more pro-nounced in deeper soil layers. Over the entire soil prole between0 and 40 cm, the moisture increase in boxes with vegetation coverwas 1.82.0 times greater than that in BL boxes. ANOVA indicatedthat there were no signicant differences in moisture increase be-tween upslope and down slope sampling sites but that there was asignicant difference between BL boxes and RS boxes (p=0.05).

    After rainfall, thewater storage increment for the 010 cm soil layerincreased with the rainfall intensity, whereas that for the entire 040 cm prole initially increased and then decreased gradually with in-creasing rainfall intensity. The relationship between the water storageincrease for the 040 cm soil layer and rainfall intensity was describedby an inverted parabola, with the highest water storage increments

    (36.82.9 mm) occurring at a rainfall intensity of 1.5 mm min1

    and the lowest (21.63.1 mm) occurring at 2.0 mm min1. Therewere no signicant differences in the soil moisture increase for the dif-ferent rainfall intensities (p>0.05).

    On increasing the slope of the boxes from 8.8% to 36.4%, the soilmoisture increase initially rose and then fell gradually. The highestaverage soil moisture increase over the entire 040 cm soil prole(41.3 7.2 mm) was achieved at a slope angle of 17.6%; on increasingthe slope to 36.4%, the soil moisture increase declined sharply, to17.92.0 mm. ANOVA revealed that there was a signicant differ-ence in the water storage increase between gradual slopes (8.8%and 17.6%) and steep slopes (26.8% and 36.4%).

    Vegetation signicantly increased wetting front's migration dis-tance and could substantially increase soil water storage after rain,

    as well as prolong the soil redistribution process. We studied two

    Table 7

    Regression coefcient tests for tting Eq.(4).

    Coefcient Std. Error T p VIF

    Constant 0.501 0.091 5.497 b0.001ri 0.518 0.106 4.874 b0.001 0.263cv 0.693 0.094 7.369 b0.001 1.058G 0.207 0.136 1.523 0.148 1.900asm 0.259 0.127 2.039 0.059 1.762

    8 J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    9/10

    underlying surfaces (RS and BL boxes) under similar conditions andfound that the wetting front in the RS box reached a soil depth of3040 cm whereas in the BL box it reached only the 2030 cmlayer. Moreover, the soil moisture content in the RS box increasedby more than a factor of two whereas that in the BL box was muchless substantial. The water redistribution process continued in theRS box even after the BL box had almost achieved a steady state21 h after the termination of rainfall.

    The BL boxes had the lowest in

    ltration recharge coef

    cients of allsurface types studied, with an average value of 54.9% for 20 rainfallevents. The average value for boxes with vegetation cover was 1.5times that for BL boxes. We used regression analyses to express therecharge coefcient as a function of the rainfall intensity, vegetationcover, slope gradient, and initial soil water content. The expressionso obtained indicates that the recharge coefcient declines graduallywith increasing rainfall intensity, slope, and initial soil water content,and that it increases with the extent of vegetation cover. Moreover,the vegetation cover was the factor with the greatest impact on therecharge coefcient.

    Acknowledgement

    We would like to thank Dr. Juan Wang, Dr. Xidong Gao and Dr. MinLi for their valuable comments on this manuscript. This work was

    jointly supported by the Special Foundation of National Science &Technology Supporting Plan (2011BAD29B09), the Supporting Pro-

    ject of Young Technology Nova of Shaanxi Province (2010KJXX04),the Supporting Plan of Young Elites of Northwest A&F University,the National Natural Science Foundation of China (31172039) andthe 111 Project of the Chinese Education Ministry (No. B12007).

    References

    Abu-Awwad, A.M., 1997. Water inltration and redistribution within soils affected by asurface crust. Journal of Arid Environments 37, 231242.

    Adams, J.E., Kirkham, F., Neilsen, P.P., 1957. A portable inltrometer and physicalassessment of soil in place. Soil Science Society of America 21, 473477.

    Adekalu, K.O., Olorunfemi, I.A., Osunbitan, J.A., 2007. Grass mulching effect on inltra-tion, surface runoff and soil loss of three agricultural soils in Nigeria. BioresourceTechnology 98, 912917.

    Agassi, M., Levy, G.J., 1991. Stone cover and rain intensity: effects on inltration,erosion and water splash. Australian Journal of Soil Research 29 (4), 565575.

    Alves Sobrinho, T., Gmez-Macpherson, H., Gmez, J.A., 2008. A portable integratedrainfall and overland ow simulator. Soil Use Manage 34, 163173.

    Arnon, I., 1972. Crop production in arid regions. Learned Hill Books, vol. (1), p. 650.Assouline, S., Mualem, Y., 1997. Modeling the dynamics of seal formation and its effect

    on inltration as related to soil and rainfall characteristics. Water ResourcesResearch 33, 15271536.

    Assouline, S., Ben-Hur, M., 2006. Effects of rainfall intensity and slope gradient on thedynamics of interrill erosion during soil surface sealing. Catena 66 (3), 211220.

    Bao, B., Bi, H.X., Yun, L., Gao, L.B., Xu, H.S., An, Y., 2012. Response of soil moisture toprecipitation in Robinia pseudoscacia forestland in loess region of western ShanxiProvince, northern China. Journal of Beijing Forestry University 34 (2), 8489 (InChinese with English abstracts).

    Beven, K., Germann, P., 1982. Macropores and water ow in soils. Water ResourceResearch 18, 13251331.

    Black, P.E., 1972. Hydrograph responses to geomorphic model watershed characteristics

    and precipitation variables. Journal of Hydrology 17, 309

    329.Blschl, G., Sivapalan, M., 1995. Scale issues in hydrological modelling: a review.Hydrological Processes 9, 251290.

    Boers, Th.M., Ben-Asher, J., 1982. A review of rainwater harvesting. Agricultural WaterManagement 5 (2), 145458.

    Bond, R.D., 1964. The inuence of themicroora on the physical properties of soil. Fieldstudies on water repellent sands. Australian Journal of Soil Research 2, 123131.

    Bouwer, H., 1986. Intake rate: cylinder inltrometer [A]. In: Kiute, A. (Ed.), Methods ofSoil Analysis, Part I, Physical and Mineralogical Methods [C]: Madison,WI,AgronomyMonograph No.9(Second ed.): American Society of Agronomy.Soil Science Society ofAmerica, pp. 825844.

    Branson, F.A., Gifford, F.G., Owen, J.R., 1972. Rangeland hydrology. Range Science SeriesNo. 1. Society for Range Management, Denver, Colo., U.S.A., p. 84.

    Bubenzer, G.D., 1979. Inventory of rainfall simulators. Proc. of the Rainfall SimulatorWorkshop, Tucson, AZ, ARM-W-10/July 1979, pp. 120130.

    Cerd, A., Garca-Fayos, P., 1997. The inuence of slope angle on sediment, water andseed losses on badland landscapes. Geomorphology 18 (2), 7790.

    Chaplot, V., Le Bissonnais, Y., 2000. Field measurements of interrill erosion underdifferent slopesand plot sizes. Earth Surface Processes andLandforms 25, 145153.

    Chen, H.,Cai,Q.G.,1990. Experimental Study on theEffect of Slopeon Runoff andInltration.Experimental Research on Soil Erosion Law in Loess Plateau Region of Western ShanxiProvince. Water Power Press, Beijing . (In Chinese).

    Chen, L., Huang, Z., Gong, J., Fu, B., Huang, Y., 2007. The effect of land cover/vegetation onsoil water dynamic in the hilly area of the loess plateau, China. Catena 70, 200208.

    Chen, X.A., Cai, Q.G., Zheng, G.M., Li, J.L., 2011. Empirical soil erosion model for singlerainstorm in Chabagou drainage basin. Progress in Geography 30 (3), 325329(In Chinese with English abstracts).

    Coleman, E.A., 1953. Vegetation and Watershed Management. Ronald Press Company,New York, p. 412.

    De Giesen, N.V., Stomph, T.-J., Ajavi, A.E., Bagavoko, F., 2011. Scale effects in Hortonian sur-

    face runoff on agricultural slopes in West Africa: eld data and models. Agriculture,Ecosystems and Environment 142, 95101.Dregne, H.E., 1991. Arid land degradation: a result of mismanagement. Geotimes 36,

    1921.Dunj, G., Pardini, G., Gispert, M., 2004. The role of land use-land cover on runoff

    generation and sediment yield at a micorplot scale, in a small Mediterraneancatchment. Journal of Arid Environment 57, 99116.

    Eldridge, D.J., Zaady, E., Shachak, M., 2000. Inltration through three contrastingbiological soilcrustsin patterned landscapesin the Negev, Israel. Catena 40,323336.

    Fohrer, N., Berkenhagen, J., Hecker, J.-M., Rudolph, A., 1999. Changing soil and surfaceconditionsduringrainfall single rainstorm/subsequent rainstorms. Catena 37, 355375.

    Foley, J.L., Silburn, D.M., 2002. Hydraulic properties of rain impact surface seals onthree clay soils inuence of raindrop impact frequency and rainfall intensityduring steady state. Australian Soil Research 40, 10691083.

    Fraser, I., Harrod, T.R., Haygarth, P.M., 1999. The effect of rainfall intensity on soil erosionand particulate phosphorus transferfrom arable soils. Water Science and Technology39 (12), 4145.

    Fu, B., Wang, J., Chen, L., Qiu, Y., 2003. The effects of land use on soil moisture variationin the Danangou catchment of the Loess Plateau, China. Catena 54, 197213.

    Fu, B., Wang, Y.K., Zhu, B., Wang, D.J., Wang, X.T., Wang, Y.Q., Ren, Y., 2008. Experimen-tal study on rainfall inltration in sloping farmland of purple soil. Transactions ofthe CSAE 24 (7), 3943 (In Chinese with English abstracts).

    Galle, S., Ehrman, M., Peugeot, C., 1999. Water balance in a banded vegetation pattern:a case study of tiger bush in western Niger. Catena 37 (12), 197216.

    Gmez, J.A., Nearing, M.A., 2005. Runoff and sediment losses from rough and smoothsoil surfaces in a laboratory experiment. Catena 59 (3), 253266.

    Greene, R.S.B., Hairsine, P.B., 2004. Elementary processes of soilwater inltration andthresholds in soilsurface dynamics: a review. Earth Surface Processesand Landforms29, 10771091.

    Gyssels, G., Poesen, J., Bochet, E., Li, Y., 2005. Impact of plant roots on the resistance ofsoils to erosion by water: a review. Progress in Physical Geography 22, 189217.

    Hart, G.E., 1984. Erosion from simulated rainfall on mountain rangeland in Utah.Journal of Soil and Water Conservation 39, 330334.

    Hawke, R.M., Price, A.G., Bryan, R.B., 2006. The effect of initial soilwater content and rain-fall intensity on near-surface soil hydrologic conductivity: a laboratory investigation.Catena 65, 237346.

    Hillel, D., 1960. Crust formation in loessial soils. Transactions of the 7th InternationalCongress of Soil Science, Madison, Wisconsin, pp. 330339.

    Hillel, D., 1971. Soil and Water. Academic press, New York.Hillel, D., 1998. Environmental Soil Physics. Academic Press, New York.Hu, W., Shao, M.A., Wang, Q.J., 2006. Study on spatial variability of soil moisture on the

    recultivated slop-land on the Loess Plateau. Advances in Water Science 17 (1),7481 (In Chinese with English abstracts).

    Huang, J., Wu, P.T., Zhao, X.N., 2010. Impactof slope biological regulated measures on soilwater inltration. Transactions of the CSAE 26 (10), 2937 (In Chinese with Englishabstracts).

    Iserloh, T., Wolfgang, F., Ries, J.B., Seeger, M., 2010. Design and calibration of the smallportable rainfall simulator of Trier University. Geophysical Research Abstracts 12,EGU2010EGU2769 (02.-07.05.2010, Vienna, Austria).

    Janeau, J.L., Briquet, J.P., Planchon, O., Valentin, C., 2003. Soil crusting and inltration onsteep slopes in northern Thailand. European Journal of Soil Science 54 (3),543553.

    Jiang, D.S., Huang, G.J., 1984. Simulated experiment on the inuence of slope gradient onrainfall inltration. Bulletin of Soil and Water Conservation 4 (4), 1013 In Chinesewith English abstracts.

    Jin, C.X., Cai, Q.G., Wang, Z.K., 1995. An experimental study of inltration and erosion

    under slope gradients and vegetal covers. Chinese Geography 4, 62

    73.Kato, H.,Onda, Y., Tanaka, Y.,Asano, M.,2009. Field measurementof inltrationrate using anoscillating nozzle rainfall simulator in the cold, semiarid grassland of Mongolia. Catena76, 173181.

    Lei, Z.D., Yang, S.X., Xie, S.C., 1988. Soil Water Dynamics. Tsinghua University press, Beijing.(77 pp. In Chinese).

    Leonard, J., Andrieux, P., 1998. Inltration characteristics of soils in Mediterraneanvineyards in Southern France. Catena 32, 209223.

    Li, Y., Shao,M.A., 2006. Effects of rainfallintensity on rainfall inltration and redistributionin soil on Loess slope land. Chinese Journal of Applied Ecology 17 (12), 2271 2276(In Chinese with English abstracts).

    Li, Y., Shao, M.A., 2007a. Experiment studies on water and sediment movement for Lousoil during rainfall on Loess Slope Land. Journal of Soil and Water Conservation 21(4), 2933 (In Chinese with English abstract).

    Li, Y., Shao, M.A., 2007b. Experimental study on inuence factors of rainfall and inltra-tion under articial grassland coverage. Transactions of the CSAE 23 (3), 1823 (InChinese with English abstracts).

    Li, Y., Xu,X.Q., Zhu,X.M., 1992. Preliminary study on mechanism of plant roots to increasesoil antiscouribility on the Loess Plateau. Science in China 35 (9), 10851092.

    9J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments, Catena (2012),http://dx.doi.org/10.1016/j.catena.2012.10.013

    http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013
  • 8/10/2019 Effects of Rainfall Intensity, Underlying Surface and Slope Gradient on Soil Infiltration

    10/10

    Li, X.Y., Liu, L.Y., Gao, S.Y., Shi, P.J., Zou, X.Y., Hasi, E., Zhang, C.L., 2005. Microcatmentwater harvesting for growing Tamarix ramosissima in the semiarid loess regionof China. Forest Ecology and Management 214, 111117.

    Liu, G.C., Liao, X.R., Zhang, X.W., 2000. Practices of soil and water conservation for steepsloped-land in hilly area of Sichuan Basin. Bulletin of Soil and Water Conservation20 (6), 3941 (In Chinese with English abstract).

    Liu, H., Lei, T.W., Zhao, J., Yuan, C.P., Fan, Y.T., Qu, L.Q., 2011. Effects of rainfall intensityand initial soil water content on soil inltrability under rainfall conditions usingthe run off-on-out method. Journal of Hydrology 396 (12), 2432.

    Llorens, P., Domingo, F., 2007. Rainfall partitioning by vegetation under Mediterraneanconditions. Review of studies in Europe. Journal of Hydrology 335 (12), 3754.

    Luce, C.H., 1997. Effectiveness of road ripping in restoring inltration capacity of forestroads. Restoration Ecology 5 (3), 265270.Mah, M.G.C., Douglas, L.A., Ringrose-Voase, A.J., 1992. Effects of crust development and

    surface slope on erosion by rainfall. Soil Science 154, 3743.Marston, R.B., 1952. Ground cover requirements for summer storm runoff on aspen

    sites in northern Utah. Journal of Forestry 54 (4), 303307.Martnez-Murillo, J.F., Nadal-Romero, E., Regs,D., Cerd, A., Poesen, J.,2012. Soilerosion

    and hydrology of the western Mediterranean badlands throughout rainfall simula-tion experiments: a review. Catenahttp://dx.doi.org/10.1016/j.catena.2012.06.001.

    McIntyre, D.S., 1958. Permeability measurements of soil crusts formed by raindropimpact. Soil Science 85, 85189.

    McLeod, M.K., MacLeod, D.A., Daniel, H.,2006.The effectof degradation of phalaris+whiteclover pasture on soil water regimes of a Brown Chromosol on the NorthernTablelands of NSW, Australia. Agricultural Water Management 82 (3), 318342.

    Meyer, L.D., 1979. Methods of attaining desired characteristics in rainfall simulation.Rainfall Simulator Workshop Tucson, Arizona. Agric. Review Manual ARM-W-10,pp. 3544.

    Molina, A., Govers, G., Vanacker, V., Poesen, J., Zeelmaekers, E., Cisneros, F., 2007. Runoffgeneration in a degraded Andean ecosystem: ineration of vegetation cover and

    land use. Catena 71, 357370.Moreno-de las Heras, M., Espigares, T., Merino-Martn, L., Nicolau, J.M., 2011.

    Waterrelated ecological impacts of rill erosion processes in Mediterranean-dryreclaimed slopes. Catena 84 (3), 114124.

    Morgan, R.P.C., 2005. Soil Erosion and Conservation, Third ed. Blackwell Publishing,Oxford, UK, p. 303.

    Morin, J., Benyamini, Y., 1977. Rainfall inltration into bare soils. Water ResourcesResearch 14, 813817.

    Moss, A.J., Green, T.W., 1987. Erosive effects of large water drops (gravity drops) thatfall from plants. Australian Journal of Soil Research 25, 920.

    Nassif, S.H., 1975. The inuence of slope and rain intensity on runoff and inltration.Hydrological Sciences Bulletin 20 (4), 539552.

    Navas, A., Alberto, F., Machn, J., Galn, A., 1990. Design and operation of a rainfallsimulator foreld studies of runoff and soil erosion. Soil Technology 3 (4), 385397.

    Niu, H.,2009.Researchof antierosive mechanism and control indicators of biotec roadon theloess plateau. Master's thesis, NorthwestA & F University, Yangling, China InChinese with English abstracts.

    Pall, R., Dickinson, W.T., Beals, D., Mcgirr, R., 1983. Development and calibration of arainfall simulator. Canadian Agricultural Engineering 25, 181187.

    Pan, C.Z., Shangguan, Z.P., 2006. Inuence of grass and moss on runoff and sedimentyield on sloped loess surfaces under simulated rainfall. Hydrological Processes 20(18), 38153824.

    Panini, T., Torri, D., Pellegrini, S., Pagliai, M., Sanchis, M.P.S., 1997. A theoretical approachto soil porosity and sealing development using simulated rainstorms. Catena 31 (3),199218.

    Parsons, A.J., Brazier, R.E., Wainwright, J., Powell, D.M., 2006. Scale relationships inhillslope runoff and erosion. Earth Surface Processes and Landforms 31, 13841393.

    Philip, J.R., 1957a. The theory of inltration:1.The inltration equation and its solution.Soil science 83, 345357.

    Philip, J.R., 1957b. The theory of inltration: 5.The inuence of the initial moisture con-tent. Soil Science 84 (4), 329339.

    Poesen, J., 1986. Surface sealing as inuenced by slope angle and position of simulatedstones in the top layer of loose sediments. Earth Surface Processes and Landforms11 (1), 110.

    Poesen, J.W.,Torri, D., Bunte, K., 1994. Effects of rock fragments on soil erosion by waterat different spatial scales: a review. Catena 23, 141166.

    Poulenard, J., Podwojewski, P., Janeau, J.-L., Collinet, J., 2001. Runoff and soil erosion

    under rainfall simulation of Andisols from the Ecuadorian Pramo: effect of tillageand burning. Catena 45, 185207.Puigdefbregas, J., Barrio, G., Boer, M., Gutierrez,L., Sol, A., 1998.Differential responses

    and channel elements to rainfall events in a semi-arid area. Geomorphology 23,337351.

    Raclot, D., Le Bissonnais, Y., Louchart, X., Andrieux, P., Moussa, R., Voltz, M., 2009. Soiltillage and scale effects on erosion from elds o catchment in a Mediterraneanvineyard area. Agriculture, Ecosystems and Environment 134, 201210.

    Regs, D., Serrano-Muela, P., Nadal-Romero, E., Lana-Renault, N., 2010. Anlisis de lainltracin en elacin con el uso del suelo y su estado fsico en el Pirineo Central.

    In: beda, W., Vericat, D., Batalla, J. (Eds.), Avances de la Geomorfologa en Espaa20082010: XI Reunin Nacional de Geomorfologa. Solsona.

    Romero, C.C., Stroosnijder, L., Baigorria, G.A., 2007. Interrill and rill erodibility in thenorthern Andean Highlands. Catena 70 (2), 105113.

    Rmkens, M., Baumhardt, R., Parlange, J., Whistler, F., Parlange, M., Prasad, S., 1985.Rain-induced surface seals: their effect on ponding and inltration. AnnalesGeophysicae 4, 417424 (series B).

    Ruiz-Sinoga, J.D., Martnez-Murillo, J.F., 2009. Hydrological response of abandonedagricultural soils along a climatological gradient on metamorphic parent materialin southern Spain. Earth Surface Processes and Landforms 34 (15), 2047 2056.

    Schindewolf, M., Schmidt, J., 2012. Parameterization of the EROSION 2D/3D soil erosion

    model using a small-scale rainfall simulator and upstream runoff simulation. Catena91, 4755.Schmidt, J., 2000. Soil ErosionApplication of Physically Based Models. Springer, Berlin,

    Heidelberg, New York.Schmidt, J., 2010. Effects of soil slaking and sealing on in ltration-experiments and

    modelapproach.Proceedingsof the19thWorldCongress ofSoil Science: Soil solutionsfor a changing world, Brisbane, Australia, 16 August 2010, the physics of soil porestructure dynamics 2010, pp. 2932.

    Schmidt, B.L., Shrader, W.D., Moldenhauer, W.C., 1964. Relative erodibility of three loessderived soils in Southwestern Iowa. Soil Science Society of America Proceedings 28,570574.

    Schwartz, R.C., Baumhardt,R.L., Evett, S.R., 2010. Tillage effects on soilwaterredistributionand bare soil evaporation throughout a season. Soil & Tillage Research 110 (2),221229.

    Shao, M.A., 1985. Determining hydraulic parameters of unsaturated soils from soilmoisture redistribution. Journal of Institute of Soil and Water Conservation, AS &MWR 2, 4753 (In Chinese with English abstracts).

    Singer, M.J., Blackard, J., 1982. Slope angleinterrill soil loss relationships for slopes upto 50%. Soil Science Society of America Journal 46, 12701273.

    Smets, T., Poesen, J., Knapen, A., 2008a. Spatial scale effects on the effectiveness oforganic mulches in reducing soil erosion by water. Earth-Science Reviews 89,112.

    Smets, T., Poesen, J., Bochet, E., 2008b. Impact of plot length on the effectiveness ofdifferent soilsurface covers in reducing runoff and soil loss by water. Progress inPhysical Geography 32 (6), 654677.

    Vahabi, J., Nikkami, D., 2008. Assessing dominant factors affecting soil erosion using aportable rainfall simulator. International Journal of Sediment Research 23, 376386.

    Valentin, C., 1991. Surface crusting in two alluvial soils of northern Niger. Geoderma48, 201222.

    Walsh, R.P., Coelho, C.O., Elmes, A., Ferreira, A.J., Goncalves, A.J., Shakesby, R.A., Ternan,J.L., Williams, A.G., 1998. Rainfall simulation plot experiments as a tool in overlandow and soil erosion assessment, north-central Portugal. Geokodynamik 19 (34),139152.

    Wang, X.D., Li, G.B., Wang, D.W., 2005. Research on features and ecological function ofplant root channel. Journal of China Institute of Water Resources and HydropowerResearch 3 (1), 7478 (In Chinese with English abstracts).

    Wang, X.P., Cui,Y., Pan,Y.X., Li, X.R., Young, M.H., 2008. Effect of rainfall characteristics oninltration and redistribution patterns in revegetation-stabilized desert ecosystems.

    Journal of Hydrology 358 (12), 134143.Wei, W., Chen, L.D., Fu, B.J., Huang, Z.L., Wu, D.P., Gui, L.D., 2007. The effect of land uses

    and rainfall regimes on runoff and soil erosion in the semi-arid loess hilly, China.Journal of Hydrology 335, 247258.

    Weigert, A., Schmidt, J., 2005. Water transport under winter conditions. Catena 64,193208.

    Wischmeie, W.H., Smith, D.D., 1978. Predicting rainfall erosion losses: a guide to conser-vation planning. Agricultural Handbook No. 537. U.S. Department of Agriculture,Washington, DC.

    Wu, X.Y., Zhang, L.P., 2006. Research on effecting factors of precipitation's redistribu-tion of rainfall intensity, gradient and cover ratio. Journal of Soil and Water Conser-vation 20 (4), 2830 (In Chinese with English abstracts).

    Wu, P.T., Wang, Y.K., Feng, H., Fan, X.K., Gao, J.E., 2003. Innovation and development ofsoiland water conservationscience in China. Scienceof Soiland Water Conservation1(2), 8487 (In Chinese with English abstracts).

    Xu, X.X., Liu, W.Z., Gao, P., Mu, X.M., 2003. The discussion on soil moisture distribution-al diversity in hilly Loess Plateau region. Ecology and Environment 12 (1), 5255(In Chinese with English abstracts).

    Yuan, J.P., Lei, T.W., Guo, S.Y., Jiang, D.S., 2001. Study on spatial variation of inltration

    rates for small watershed in loess plateau. Journal of Hydraulic Engineering 10,8892 (In Chinese with English abstracts).Yun, X.X., Zhang, X.X., Li, J.L., Zhang, M.L., Xie, Y.Y., 2006. Effects of vegetation cover and

    precipitation on the process of sediment produced by erosion in a small watershedof loess region. Acta Ecologica Sinica 26 (1), 18 (In Chinese with English abstract).

    Zheng, M.G., Cai, Q.G., Chen, H., 2007. Effect of vegetation on runoff-sediment yieldrelationship at different spatial scales in hilly areas of the Loess Plateau, NorthChina. Acta Ecologica Sinica 27 (9), 35723581.

    Zhou, P.H., Dou, B.Z., Sun, Q.F., Liu, E.M., Liu, B.W., 1981. Preliminary study of rainfallenergy. Bulletin of Soil and Water Conservation 1, 5161 (in Chinese).

    10 J. Huang et al. / Catena xxx (2012) xxxxxx

    Please cite this article as: Huang, J., et al., Effects of rainfall intensity, underlying surface and slope gradient on soil in ltration under simulatedrainfall experiments Catena (2012) http://dx doi org/10 1016/j catena 2012 10 013

    http://dx.doi.org/10.1016/j.catena.2012.06.001http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.10.013http://dx.doi.org/10.1016/j.catena.2012.06.001