ῐ
J. Jpn. Soc. Soil Phys.

No. +*2, p. /-ῌ0/ ῍,**2῎

Evaluating Inﬂuence of Di#erent Cover Materials on
Runo# and Sediment Loss from Bare Upland
Soil Using Laboratory Rainfall Simulator
Taisuke ONISHI*, Makoto KATO* and Taku NISHIMURA*** United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology,-ῌ/ῌ2 Saiwai-cho, Fuchu-shi, Tokyo +2-ῌ2/*3 Japan** Graduate School of Agricultural and Life Science, University of Tokyo,+ῌ+ῌ+ Yayoi, Bunkyo-ku, Tokyo ++-ῌ20/1 Japan
Abstract
The use of composted organic matter as soil surface cover is recently viewed as a potential
application for erosion control similarly to straw cover. However, limited information on thee#ect of these cover materials on erosion from bare soil is available. This study evaluates twocover materials, rice straw and cattle manure compost, with a focus on the relationship between
soil surface coverage (expressed in arealῌ) and soil loss from bare upland ﬁeld. A clay loam
Andisol was packed into a +., m *.-/ m *.+, m soil box with a slope of +.ῌ and subjected tosimulated rainfall of ./.+ mm hr+ for +** minutes. The soil surface was either left bare or wascovered with rice straw (Oryza Sativa L.) or cattle manure compost at a surface coverage of -* areal
ῌ for straw, -/ arealῌ for compost, and 0* arealῌ for both materials. During the simulated
rainfall, surface runo# was periodically collected to determine sediment concentration andinﬁltration rate. As the coverage rate increased from -* or -/ to 0* arealῌ, the straw and compost
covers acted to signiﬁcantly reduce the sediment concentration. The observed reduction in
sediment loss from the covered soils resulted from the direct interception of raindrops andtrapping of sediment by the cover ; however, neither cover material was able to reduce the runo#
rate. The total runo# volume was higher for compost-covered soils than for bare or straw-coveredsoils. This result may reﬂect the development of a depositional crust over the soil surface. Suchcrusts formed in sediment-trap areas close to pieces of the covering material.
Key words : Cattle manure compost, Surface coverage, Runo#, Erosion, Surface crust+.

Introduction

Soil erosion occurs where the bare soil surface is exposed to rainfall. Plant residues suchas rice straw have been conventionally used
for erosion control and soil conservation insloping upland ﬁelds in Japan (Yamamoto etal., +33/). However, in recent times, rice straws
are chopped and spread over the paddy soil byusing a harvesting machine while the amountof land for rice paddies has been decreasing,and biomass-energy use of the straw is consid-

ering. Under this situation, the use of straw asan organic resource for upland ﬁeld soil conservation has become limited. It is therefore necessary to investigate more e#ective and lesslabor-intensive soil conservation measures using alternative materials (Nakao et al., ,**,).
Livestock manure compost has been traditionally applied to agricultural ﬁelds in Japanas an organic fertilizer or soil amendment. Recently, its application is accelerated as a renewable use of organic waste for sustainable farming (MAFF, ,**,, Shimizu, ,**/). Many studies

῏

54

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were focused on the nutrient release performance of livestock manure compost in the soil
and/or on the improvement of soil physicochemical properties (e.g. Nishida et al., +33/ ;Kawata et al., +330 ; Kato and Yoneda, ,**+),
however, few studies have focused on the application of livestock manure compost and its
e#ect on soil erosion upon sloping uplandﬁelds in Japan (Watanabe and Kawabata, +32*).
From this perspective, an investigation of theuse of animal waste compost for soil conservation as an alternative to rice straw would bevaluable in Japan.
Some studies showed the performance of organic materials in minimizing sediment loss
and runo# (Foltz and Dooley, ,**- ; Benik etal., ,**-). Foltz and Dooley (,**-) showed agreater reduction in both sediment loss andruno# with a cover of wood strand (thin rectangular wood piece) than for a straw cover forthe same surface coverage, 1* areal῍. Other
than plant residues, Agassi et al. (+332) showeda reduction in surface runo# rate with highapplication rates (0*, +,*, and +2* t ha+ in dry
weight) of composted municipal solid waste.
Faucette et al. (,**.) demonstrated reductions
in runo# and sediment loss by covering the soil
with a / cm thick layer of aged poultry litter,composted poultry litter, biosolids, and yard
waste. They found reduction in runo# andsediment loss by covering with these composts
except for the application of the poultry litter.
Previous studies have also documented thee#ects of surface-applied livestock compost on
runo# and soil loss from ﬁeld plots (Gilley andEghball, +332) and laboratory soil boxes (Vadas
et al., ,**.) under simulated rainfall. Gilley andEghball (+332) applied simulated rainfall of 0.
mm hr+ for + hour to no-till ﬁeld plots where
beef cattle compost was spread over a sorghum
residue at a cover rate of ,-῍. The application
rates (dry weight basis) for the compost were
either ,..1 t ha+ to satisfy corn phosphorus requirement or +,0 t ha+ for that of nitrogen.
They reported no signiﬁcant di#erence in runo# rate and soil loss following the application+*2

,**2

of compost under the no-till conditions.
In the above-cited studies, the composts wereapplied to soil surface with huge amount (ῌ0*t ha+) (Agassi et al., +332) or to form grossly
thick surface compost-layer above soil (Faucette et al., ,**.). Too much compost application, however, might cause a risk of nitrate pollution of ground water and may create anaerobic condition following rainfall event (Faucette et al., ,**/) which is harmful to plant seedgermination. And in Japan, some studies pointed out that too much compost application may
cause the problem of excess potassium andphosphorous application to soil (i.e. Goto andEguchi, +331 ; Nanzyo and Yamada, ,**/), which
diminishes plant growth. Also, too much application of composts may rise risk of groundwater pollution by leaching of compost derived
chemicals. From this point of view, compost
application should be limited and a surface
cover rate might be less than +**῍. It is therefore important to evaluate the relationship between soil surface coverage by livestock manure compost and erosion rates in sloping upland ﬁelds in Japan. Investigations of the e#ectiveness of various surface coverages in termsof minimizing soil loss may help farmers to
adopt more e#ective practices, especially forsoil conservation purpose, of surface mulching.
Previous studies have reported reductions insoil loss with increasing soil surface coverage(Singer and Blackard, +311 ; Greene et al., ,**.),
however, the single e#ect of compost applied
at relatively low rate (i.e. low coverage rate) on
runo# and soil loss from bare soil remains
unclear. Also, the relationship between surface coverage and changes in surface runo#
and inﬁltration rate is still not fully understoodand requires further study (Ruan et al., ,**+ ;Greene et al., ,**.).
The objective of the present study is to evaluate two cover materials, cattle manure compost and rice straw in relatively small amounts,
from the relationship between soil surface coverage, runo# and sediment loss from bare upland soil. We also discuss changes in funda- : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator

mental soil surface hydrological properties following the application of cattle manure compost.
Furthermore, soil erosion is complicated phenomenon, and many factors, such as antecedent soil moisture content and timing and intensity of rainfall, a#ect soil loss. In this study, we
employed laboratory experiment under simulated rainfall to control experimental condition
for precise discussion on interrill erosion as interacted by surface treatments. Also in evaluating surface coverage, a grid sampling method(Singer and Blackard, +311 ; Foltz and Dooley,,**-), similar to the photographic method(Laﬂen et al., +32+), has often been employed.
However, it can involve operator-induced andsystematic errors in determining surface coverage and be less accurate (Han and Hayes, +33*).
It is necessary to adopt precise evaluation ofcoverage to consider relations among extent ofsoil surface coverage, surface cover materialand soil loss. Recent image analysis technique
can help to improve accuracy of surface coverage evaluation and was employed in this study.
,.

Materials and Methods,. + Soil and soil-box preparation
In the present study, we used a clay loam
Andisol (.2.3ῌ sand, --.3ῌ silt, and +1.,ῌ clay)
as a typical sloped upland soil in Japan. The
soil was sampled from an upland ﬁeld of theField Science Center of the Tokyo Universityof Agriculture and Technology (TUAT). Soilpassed through a - mm mesh screen was pack-55

ed into a soil box of +., m in length, *.-/ m inwidth, and *.+, m in depth (Fig. +) at a bulk
density of *.0, Mg m-. The soil was packed at
a mass wetness of 1/ῌ using a wooden soil
tamper at an increment of +./ cm layers to forma 0 cm thick soil layer upon a / cm thick gravel
layer. A cotton cloth was inserted at the boundary of the soil and gravel layers to support
the soil structure. Discontinuities between thefour +./ cm thick layers were minimized by
disturbing the surface of each layer (Singer
and Walker, +32-) using a sharp metal rod prior
to packing the overlying layer. The box had aslope of +.ῌ (2), which is an upper-limit of thestandard slope for reclaimed upland ﬁelds inmountainous areas of Japan (MAFF, ,**0). A
metal ﬂume at the lower end of the box anddrainage outlets (f+/ mm) at the lower frontof the box were connected to collect surface
water and percolated water. In this study the
packed soil represents a ﬂat surface such as
seed bed, which is particularly vulnerable toerosion (Kleinman et al., ,**.), especially under
the high rainfall intensity. However, it is ourintention to evaluate di#erent contributes ofcover materials to runo# generation or sediment transport under such an erosive condition.
,. , Rainfall simulation
Simulated rainfall was applied using a nozzleoscillating-type rainfall simulator (Niebling etal., +32+) from +.2 m above the soil surface. We
used two veejet 2*+** nozzles (Spraying System CO., USA). The rainfall was set at an av-

Fig. + Schematic of the soil box used in this experiment.

56

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erage of ./.+ mm hr+ for +** minutes. The rain
intensity had a coe$cient of variance of *.*within the +., *.-/ m rainfall area, as determined from 0/ small rain gauges with a crosssectional area of approximately +3.0 cm,. Meyerand Harmon (+313) reported this rainfall simulator can represent raindrop size distribution
and rainfall energy of gentle natural rainfall insouthern part of USA with operating waterpressure of .+ KN m, and water drop hight of,.. m. In this study, we selected water operating water pressure of -../ KN m, instead of .+KN m,, since former number could give us
more even distribution of rainfall intensity.
Also, height of the rainfall simulator was +.2m
due to dimension of the experimental room.
Thus, expected rainfall energy was a little bit
lower than the natural rainfall. For the simulated rainfall, we used tap water with a meanelectrical conductivity of *., dS m+.
Runo# and subsurface drainage were collected at /-minute intervals during the simulated
rainfall. Samples of surface discharge werecollected and weighed to determine the runo#
rate and sediment concentration. To determine the inﬁltration rate, the runo# rate wassubtracted from the rain intensity. The steadystate was determined as the ﬁnal ,* minutes of
the total +**-minute rainfall event according tothe observed changes in runo# hydrographs
for ﬁve surface conditions. Four replicates weremade for bare soil, three for applied straw, andtwo for applied compost.
The surface cover materials were applied byhand to obtain the desired surface coverage (*,-* or -/, and 0* arealῌ). This was done immediately prior to the start of the rainfall. Several
hours following the half of rainfall period
when rapid drainage from the soil had ceased,
undisturbed soil samples (n+*) were takenfrom the box using a stainless steel cylinder, /.+cm in diameter and /.* cm in length, to measure
the saturated hydraulic conductivity of thesurface soil by the falling head method (Kluteand Dirksen, +320).

+*2

,. -

,**2

Cover materials and determination of
the coverage rate
Rice straw (Oryza Sativa L.) and cattle manure compost that had been composed for six
months were obtained from the Field Science
Center of TUAT. Wood shavings and chips
were mixed with the cattle manure to control
moisture content. The carbon/nitrogen ratioof the soil was ++.- while that of the compost
was +*.- as determined by using a CN coder(MT-1**Mark,, Yanaco CO., Kyoto, Japan).
Dried rice straw was cut into lengths of +*ῌ+/
cm prior to application. The carbon/nitrogenratio of the dry rice straw was not determinedin this study. It is typically much higher thanthat of the cattle manure compost, and about/* (Nishida et al., +33/), or in some case morethan 1* (Fujiwara, ,**-).
Prior to the experiment, two di#erent methods to determine the soil surface coverage,
image analysis using ImageJ software version+.,.o, which is public domain software produced by the National Institute of Health, USA(Reinking, ,**+), and conventional grid sampling method (Foltz and Dooley, ,**-) werecompared and evaluated. Surface photographs
consisting of covered and uncovered regions
were used for image analysis. The separationof these two area-types was made using an
automated binarization routine implemented
to the ImageJ software. The threshold adjustment is similar to that described by Chen et al.
(,**.). For calibration, we took sample photographs of straw cover within *.., m, quadrate
frames installed at the soil surface. In the grid
sampling method (GS), a clear gridded screen
was projected onto a photograph of the straw
cover. The surface coverage is then determined by dividing the number of grids that
contain straw bodies by the total number ofgrids (Singer and Blackard, +311).
Figure , shows the relationship between application rate in dry weight and surface coverage rate. The plotted surface coverage, as afunction of application rate for both compost
and rice straw, is ﬁtted by a power equation (Y : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator

aXb, where Y is the surface coverage, X is theapplication rate, and a and b are constants).
The dry mass weight of the cover materials
applied to the soil surface prior to the rainfall
experiment and corresponding coverage rates
are summarized in Table +. The error of the GS
in the obtained surface coverage is demonstrated by changes in the coverage rate ofstraw as determined by using two di#erent
grid sizes, +,+ and -0 grid points for the same
area (Fig. ,). The surface coverage rate of theFig. , Relationship between mass application
rate of cover materials (dry rice straw
and dry cattle manure compost) andsoil surface coverage. For rice straw,
the data were determined by image
analysis (IA) and grid sampling (GS)with two total grid point numbers (-0,+,+), measured at nine di#erent locations over the test area. The data presented by Singer and Blackard (+311)
with the GS (/,3 grid points) is also
shown (vertical bars denote standard
deviation).

GS with +,+ grid points are greater than that of
the GS with -0 grid points for each application
rate of the rice straw. The total number of grid
points was changed from +,+ to -0 by doubling
the grid interval after determining the coverage with +,+ points. The GS with +,+ grid
points showed similar result to the result ofSinger and Blackard (+311) that employed thesame grid interval as the GS with +,+ grid
points in this study. To achieve a more consistent determination method, image analysis wasused to determining the coverage rate of applied compost in the present study.
,. . Data analysis
We analyzed saturated hydraulic conductivity, steady-state runo#, and inﬁltration rates
among the di#erent surface conditions (baresoil, coverage of -* or -/, and 0* arealῌ for thetwo materials) using the non-parametric MannWhitney U-Test to identify signiﬁcant di#erences (P*.*/ or *.*+). In this study, saturated
hydraulic conductivity after rainfall had a nonparametric distribution for all surface conditions. For the runo# rate, a series of measured
data collected at /-minute intervals during thesteady-state was averaged among replicates ofeach surface condition and paired among all
the conditions to analyze the measured di#erences. Only the average values of steady-state
runo# and inﬁltration rates are reported foreach condition.
-.

Results and Discussion

Patterns of runo#, sediment concentration, and soil loss
The packed soil had a high saturated hy--. +Table + Dry weight of each cover material with given surface coverage applied on a soil box.
Cover materials and surface coverage as determined by image analysis

Dry weight (t ha+)
g m,

57

Rice straw-* areal ῌ(SC -* areal ῌ)

Rice straw
0* areal ῌ(SC 0* areal ῌ)

Cattle manurecompost-/ areal ῌ(CC -/ areal ῌ)

Cattle manurecompost0* areal ῌ(CC 0* areal ῌ)

+4/
+/*

-4/
-/*

-4*
-**

04*
0**

58

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draulic conductivity (1.., mm hr+) that wasmuch greater than the rainfall intensity of theexperiment (./.+ mm hr+). Despite this, runo#
occurred during the simulated rainfall for all
the surface treatments (Fig. -). Runo# rates
during the +** minutes of the rain event are
shown in Fig. -. Vertical bars in the ﬁgure show
the standard deviations of replicates. The runo# rate for compost-applied soil exceeded thatfor bare soil. This result is contrary to thegeneral concept that surface contact cover may
reduce surface runo# if the cover is su$ciently
close to soil surface and not be carried away by
the runo# (Marshall et al., +330). All soil surface conditions showed near steady-state run-+*2

,**2

o# when cumulative rainfall of approximately-* mm was applied.
Figure . shows changes in sediment concentration during the rainfall event for each surface condition. Sediment concentrations were
calculated as the mass of transported solid
particles per unit volume of runo# water, i.e.,grams per liter of runo#. Sampled sediments
contained both soil particles and particles
derived from composted material. Very few
coarse compost materials were transported
into bed of the ﬂume, while ﬁner particles fromthe compost were mostly suspended in runo#
water. It was easy to identify the color of runo# water from the soils with and without ap-

Fig. - Runo# from Andisol with di#erent surface coverage and mulching material. Rain intensity
was ./.+ mm hrῌ+ (vertical bars denote standard deviation).

Fig. . Changes in sediment concentration of Andisol with di#erent surface coverage and mulching material. Rain intensity was ./.+ mm hrῌ+ (vertical bars denote standard deviation).

 : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator

plied compost during the rainfall simulation.
In all conditions, the sediment concentration
decreased slightly with increased rainfall duration.
Progressive changes in cumulative sedimentloss for each surface condition during the +**minutes of rainfall are compared in Fig. /. Sediment loss from covered soils was signiﬁcantly
less (approximately /*ῌ) than that lost frombare soil, even with just -* (for straw) or -/ (forcompost) arealῌ surface coverage.
Sediment loss was greatly reduced when thesoil surface was covered at a surface coverageof 0* arealῌ. This held true for applications ofboth rice straw and cattle manure compost.
For straw-covered soil, we observed the directinterception of raindrops by pieces of straw.
This mechanism acted to reduce soil detachment by raindrop impact, and accordingly led
to a reduction in soil loss (Singer and Walker,+32-). As reported previously, straw lying across-slope can capture transported soil particles as a microsediment pond (Meyer et al., +31* ;Singer and Walker, +32-). We also observed theinterception of raindrops and capture of sediments by applied compost material. Fibers ofwaste wood mixed into the cattle manure compost contributed to the interception of raindrops. During the runo# event, some solid
composted matter was disintegrated by rain-

59

drop impact, while a portion of the waste wood
fraction was displaced from its original position by raindrop impact.
The relationship between the average steadystate runo# rate of each surface condition
during the ﬁnal ,* minute of rainfall and soil
surface coverage rates is shown in Fig. 0. The
observed changes in steady state runo# rates
were not signiﬁcantly di#erent (P*.*/) between the various surface conditions except
for the application of compost at a surface
coverage of 0* arealῌ, which showed greater
steady-state runo# than the other covered conditions and bare soil (Fig. 0). Cumulative sediment loss at the end of rainfall event for all
surface conditions and varying surface coverage rates are plotted in Fig. 1. Sediment loss
was reduced with increasing surface coveragefor both covering materials (Fig. 1). However,extent of the reduction in sediment loss may
have been smaller for the compost cover thanthat of the straw covers.
-. , Changes in soil surface permeability
The hydraulic conductivity of the uppermost / cm layer of soil decreased signiﬁcantly
during the rainfall event. The saturated hydraulic conductivity of the surface soil prior to
rainfall was 1.., mm hr+, decreasing to +1.-ῌ,1.* mm hr+ following rainfall. However, there
was no signiﬁcant di#erence (P*.*+) in theFig. / Cumulative sediment loss of Andisol with di#erent surface coverage and mulching material. Rain intensity was ./.+ mm hrῌ+ (vertical bars denote standard deviation).

60

 +*2  ,**2

saturated hydraulic conductivity of soil samples among uncovered, straw-covered, and compost-covered conditions (Table ,). A signiﬁcant di#erence (P*.*+) was only observed forsoils with compost application at -/ and 0*
arealῌ. Cover materials that remained on thesurface of the soil were carefully removed prior
to taking undisturbed soil core samples to alleviate breaking soil structure upon inserting

Fig. 0 Relationship between steady-state runo# rate (during 2* to +** min. period ofrain event) and soil surface coverage.
Data with the same letter are not signiﬁcantly di#erent at P*.*/. Rain intensity was ./.+ mm hr+ (vertical bars
denote standard deviation).

the steel cylinder. This could have enhanced
the saturated hydraulic conductivity of the undisturbed soil. The removal of covering material, both compost and straw, that acts as animpermeable media potentially enhanced hydraulic conductivity.
McIntyre (+3/2) reported a decrease in saturated hydraulic conductivity related to the formation of a surface seal. In this study, weFig. 1

Relationship between cumulative sediment loss (for +** min.) of Andisol with
di#erent surface coverage and mulching material. Rain intensity was ./.+
mm hrῌ+ (vertical bars denote standard
deviation).

Table , Comparison of steady-state inﬁltration rate and saturated hydraulic conductivity ofwhole core soil after rain and that of surface crust part. Average inﬁltration rate of eachcondition at the steady-state, 2* min to +** min of runo# event, is shown. Standard
deviation in parentheses.
Surface
Condition
Bare Soil
SC -* areal ῌ
SC 0* areal ῌ
CC -/ areal ῌ
CC 0* areal ῌ

Steady-State
Inﬁltration
Rate (mm hr+)*,*4+ a *4/
+34/ a *40
+34- a *42
+34. a +4*
+04+ b *40

Saturated Hydraulic Conductivity after Rainfall
Whole Soil Core (mm hr+)**Surface Seal Layer (mm hr+),+4. a ++41
+342 a  24+,-4- a +/42
,14* ab +143
+14- ac  24+Average : ,+42
 -41

+413 -43ND
*43/++4+,*43* .4+2
*43+ 2412

Mean values that have the same letters are not signiﬁcantly di#erent at ;* the *.*/ probability level,** the *.*+ probability level.
ND, no data.

 : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator

observed the development of a seal at the surface of covered soils. Visual observation indicated that state of the surface seal development was di#erent between the bare soil andthe covered soils. Only the bare soil surface
showed the seal development over the entire
area of it. The saturated hydraulic conductivity of the seal layer was calculated using asimilar method to that presented by McIntyre(+3/2) :LtotῌKtotlcῌkcluῌku
where Ktot is the saturated hydraulic conductivity of the entire soil column, kc is the saturated
hydraulic conductivity of the surface seal
layer, ku is the saturated hydraulic conductivity of the layer beneath the seal, lc is the thickness of the seal, lu is the thickness of the underlain layer, and the total depth of the soilcolumn was / cm (Ltotlclu). The thicknessof the surface seal layer, lc, was assumed to be*., cm, as a distinct boundary observed between the thin dense layer at the surface andthe subsoil underneath. The surface *., cm
thick layer was easy to remove and separate
from the sub-layer. For each coverage condition, one sample for every replicate was used todetermine the saturate hydraulic conductivityof the seal layer. Due to this limitation in thenumber of available soil core samples for measuring the hydraulic conductivity of the seal,
we did not undertake a statistical comparisonof di#erences in the permeability of seal layers
among di#erent conditions. No data could beobtained for the soil with -* arealῌ cover bystraw due to structural disturbance of the surface seal that occurred when collecting undisturbed core samples.
The surface seal layer showed signiﬁcantly
low saturated hydraulic conductivity, withvalues ranging from approximately + to +* mm
hr+ in the bare soil and the three covered soils(Table ,). The considerable low saturated hydraulic conductivity of the surface seal resulted in reducing the soil surface permeability. However, this function of the surface seal

61

could be more signiﬁcant in the bare soil surface than that in the covered soils where theseal formation is limited to partial area of thesoil surface.
The steady-state inﬁltration rates and saturated hydraulic conductivities of core samples
are summarized in Table ,. For bare soil, thesteady-state inﬁltration rate was close to thesaturated hydraulic conductivity of the undisturbed core soil sample. There was no signiﬁcant di#erence between steady-state inﬁltration rates (P*.*/) and the saturated hydraulicconductivities (P*.*+) of the soil under all
covering conditions except the 0* arealῌ compost cover for the inﬁltration rate. The di#erence between the average inﬁltration rate
under 0* arealῌ compost cover and the average hydraulic conductivity of all ﬁve conditions was /.1 mm hr+. This is greater than thedi#erence between the average inﬁltration rate(+3.0 mm hr+) for all other conditions and theaverage hydraulic conductivity of all ﬁve conditions (,+.2 mm hr+, Table ,). Our observations indicated that wet compost clumps acted
to seal the soil surface and provided obstacles
to inﬁltration of surface water. The presence ofcompost clumps as an additional seal appears
to explain the low degree of inﬁltration observed for a compost cover of 0* arealῌ.
-. - E#ects of surface cover on surface hydrological processes and sedimenttransport-. -. + Sediment concentration - inﬁltration
relation
Figure 2 shows the relationship between inﬁltration rate and sediment concentration at /minute sampling intervals during the +**minute rainfall event for all soil surface treatments. Di#erent trends were observed for thecovered and uncovered soil. The uncovered
bare soil showed a decline in inﬁltration ratewith increasing sediment concentration, while
covered soils showed a sharp fall in inﬁltration
rate at lower sediment concentrations relative
to bare soil. For bare soil, only eroded anddeposited ﬁne soil particles were considered to

62



+*2

,**2

Fig. 2 Trends of inﬁltration rate with sediment concentration for each treatment. Dash-dot line
indicates average inﬁltration rate of all treatments at steady-state. Mean rain intensity was./.+ mm hrῌ+.

reduce the inﬁltration rate of the soil by clogging pores and developing seal. At the sametime, some of the deposited ﬁne particles werere-detached by raindrop impact or runo# water. Steady-state inﬁltration rates were similar
for covered and uncovered soils, with average
rates of +2.0 and ,*.+ mm hr+, respectively. For
average steady-state inﬁltration of all the treatment, as indicated by the dash-dot line in Fig.
2, the sediment concentration of soil with acoverage rate of 0* arealῌ was approximately,/ῌ that of uncovered soil. If the ﬁne soil
particles transported in runo# is a main cause
for soil pore clogging and thus for the decrease
in inﬁltration rate, the sediment concentrationof the covered soil should be as high as that of
the bare soil since both soil showed similar
reduction in permeability. However, the soils
covered by straw or compost showed rather
low sediment concentration (Fig. .). As mentioned above, some of the detached ﬁner soil
particles in the covered soil were transported
by runo#, trapped by surface cover, and deposited on the soil surface. In this way, soil loss
could be reduced, and trapped soil particles
locally form depositional crust that could re-Fig. 3 Morphological feature of soil surface
with compost application after rainfall.
Arrows indicate where transported particles are deposited to form surface seal(relatively smooth area).

duce inﬁltration rate. The depositional crust
was developed mostly in sediment-trap areas
close to the covering material fractions. Fig. 3
shows compost applied to the soil surface. The
photograph shows the partial formation of asurface seal, which is visible as the relatively
smooth area in the photograph.

 : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator-. -. ,

E#ects of cover-material on runo#
generation
A decrease in inﬁltration rate under surfacecovered condition can be attributed not only tosealing but also to runo#-generation process
induced by the characteristics of the cover material. As stated previously, we observed suspended compost particles in runo# water forthe case with applied compost. These ﬁne particles may also have clogged surface soil poresand thereby acted to reduce the inﬁltration
rate. Barrington and Madramootoo (+323) investigated changes in inﬁltration rate for aclay loam soil under water-ponding conditions
by pouring sterilized manure solution onto thesoil surface. They found that a decrease in inﬁltration rate resulted from the trapping bysoil pores of particles derived from the manure.
Moreover, they reported that retention of manure-derived solids by pores was inﬂuenced by
the adsorption of manure-derived organic particles by clay components of the soil.
In the present study, the straw-covered soil
showed a decrease in inﬁltration rate with alesser increase in sediment concentration thanthat recorded for bare soil (Fig. 2). The lower
concentration of sediment was due to the trapping of sediment by straws, as the microsediment pond. Under rainfall, the microsedimentpond was puddled by raindrop impact. Particles were displaced and sorted according toparticle size during the puddling that formed adepositional crust (Le Bissonnais et al., ,**/) inthe vicinity of pieces of straw. Therefore, thestraw-covered soil showed a decrease in inﬁltration rate and increased runo# with lower
sediment concentrations (Fig. 2).
..

Conclusions

Two soil cover materials with di#erent surface coverage, rice straw as conventional
mulching material and cattle manure compost
as an alternative, were applied to a clay loam
Andisol with a slope of +.ῌ. Under simulated
rainfall, soil loss was signiﬁcantly reduced bysurface cover even with low soil surface cover-63

age. The compost cover at -/ arealῌ whichcorresponds to the application rate of - t ha+ in
dry weight could reduce the cumulative sediment loss less than /*ῌ of that from the baresoil. However, surface runo# from the soils
covered with rice straw or cattle manure compost was not reduced at coverage rates of -* or-/, and 0* arealῌ. Trends in soil loss describedin the present study involve a decrease withincreasing surface coverage rate, however,runo# behavior varied more with the nature of
the surface-covering material than with coverage rate.
The results of this laboratory study showed
an adverse impact of the surface cover, whichis generally considered to improve rain inﬁltration thus reduce runo#, on surface runo#. In
this study, a decrease in inﬁltration and related
runo# increase were observed for soil with acompost cover at 0* arealῌ (0 t ha+ in dry
weight). The increased runo# could be a major
factor to transport ﬁne compost particles into
downward slope, and then utility of the compost as organic resource could be degraded.
Regarding the e#ects of slope, rain intensity,and soil type used in this study on simulated
runo#, soil conservation beneﬁt is not assured
for the compost cover at 0* arealῌ. Further
investigations on the transport of ﬁne solids
and nutrients in runo# from surface appliedcompost under di#erent experimental conditions (i.e., slope, rain intensity) would be needed.
References
Agassi, M., Hadas, A., Benyamini, Y., Levy, G. J.,
Kautsky, L., Avrahamov, L. and Zhevelev, H.
(+332) : Mulching e#ects of composted MSW
on water percolation and compost degradation
rate. Compost Sci. Util., 0 (-) : -.ῌ.+.
Barrington, S.F. and Madramootoo, C.A. (+323) :Investigating seal formation from manure inﬁltration into soils. Trans. ASAE, -, (-) : 2/+ῌ
2/0.
Chen, Y., Monero, F.V., Lobb, D., Tessier, S. andCavers, C. (,**.) : E#ects of six tillage methods
on residue incorporation and crop performance in a heavy clay soil. Trans. ASAE, .1 (.) :

64



+**-ῌ+*+*.
Faucette, L.B., Jordan, C.F., Risse, L.M., Cabrera, M.,
Coleman, D.C. and West, L.T. (,**/) : Evaluation of stormwater from compost and conventional erosion control practices in construction
activities. J. Soil Water Conserv., 0* (0) : ,22ῌ
,31.
Faucette, L.B., Risse, L.M., Nearing, M.A., Gaskin, J.
W. and West, L.T. (,**.) : Runo#, erosion, andnutrient losses from compost and mulch blankets under simulated rainfall. J. Soil Water
Conserv., /3 (.) : +/.ῌ+0*.
Foltz, R.B. and Dooley, J.H. (,**-) : Comparison oferosion reduction between wood strands andagricultural straw. Trans. ASAE, .0 (/) : +-23ῌ
+-30.
Fujiwara, S. (,**-) : Method of composting and its
usage  from the principle to the practical .
p. +++. Rural Culture Association, Tokyo, Japan (in Japanese).
Gilley, J.E. and Eghball, B. (+332) : Runo# and erosion following ﬁeld application of beef cattle
manure and compost. Trans. ASAE, .+ (/) :+,23ῌ+,3..
Goto, S. and Eguchi, H. (+331) : Ca, Mg and K release
rates from some green manure and composts
under ﬁeld conditions. Jpn. J. Soil Sci. Plant
Nutr., 02 : 0.*ῌ0.. (in Japanese with an English
abstract).
Greene, R.S.B. and Hairsine, P.B. (,**.) : Elementary processes of soil-water interaction andthresholds in soil surface dynamics : A review.
Earth Surf. Process. Landforms, ,3 : +*11ῌ+*3+.
Han, Y. J. and Hayes, J. (+33*) : Soil cover determination by image analysis of textural information. Trans. ASAE, -- (,) : 02+ῌ020.
Kato, T. and Yoneda, K. (,**+) : E#ects of long-term
application use of compost on the physicochemical properties of andosol and yields ofcabbage and Japanese radish. J. Jpn. Soc. Soil
Phys., 21 : -ῌ+1 (in Japanese with an English
abstract).
Kawata, A., Itami, K., Kyuma, K. and Kosaki, T.
(+330) : The e#ect of organic matter on dispersibility of clays  A case study of Hikigawa reclaimed agricultural land  Soil Phys.
Cond. Plant Growth Jpn., 1/ : -+ῌ-2 (in Japanese with an English abstract).
Kleinman, P. J.A., Sharpley, A.N., Veith, T.L.,
Maguire, R.O. and Vadas, P.A. (,**.) : Evaluation of phosphorus transport in surface runo#
from packed soil boxes. J. Environ. Qual., -- :+.+-ῌ+.,-.
Klute, A. and Dirksen, C. (+320) : Hydraulic conduc-+*2

,**2

tivity and di#usivity : Laboratory methods.
pp. 021-1-.. In A. Klute (ed.) Methods of soil
analysis. Part +. Agron. Monogr. 3. ASA and
SSSA, Madison, WI.
Le Bissonnais, Y.L., Cerdan, O., Lecomte, V.,
Benkhadra, H., Souchere,◊
V. and Martin, P.
(,**/) : Variability of soil surface characteristics inﬂuencing runo# and interrill erosion.
Catena, 0, : +++ῌ+,..
Li, F. and Chaplin, J. (+33/) : Analysis of random
and systematic sampling methods for residue
cover measurement. Trans. ASAE, -2 (/) : +-/-ῌ+-0+.
Marshall, T. J., Holmes, J.W. and Rose, C.W. (+330) :++. Soil erosion and conservation. p. -+.. In Soil
Physics, -rd edn. Cambridge University Press,
Cambridge, United Kingdom.
McIntyre, D.S. (+3/2) : Permeability measurementof soil crusts formed by raindrop impact. Soil
Science, 2/ : +2/ῌ+23.
Meyer, L.D. and Harmon, W.C. (+313) : Multipleintensity rainfall simulator for erosion research on row side slopes. Trans. ASAE, ,, :+**ῌ+*-.
Meyer, L.D., Wischmeier, W.H. and Foster, G.R.
(+31*) : Mulch rates required for erosion control on steep slopes. Soil Sci. Soc. Am. Proc., -. :3,2ῌ3-+.
Nakao, S., Takagi, A. and Hosokawa, M. (,**,) :Water erosion control practices and its e#ects
on sloping upland ﬁelds. Jour. JSIDRE, 1* (1) :0+3ῌ0,, (in Japanese).
Nanzyo, M. and Yamada, K. (,**/) : Changes inchemical properties and water-percolation ofsoils overlaid with cattle manure compost. J.
Jpn. Soc. Soil Phys., 33 : ./ῌ/. (in Japanesewith an English abstract).
Niebling, W.H., Foster, G.R., Natterman, R.A.,
Nowlin, J.D. and Holbert, P.V. (+32+) : Laboratory and ﬁeld testing of programmable plotsized rainfall simulator. pp. .*/ῌ.+.. In Erosion
and sediment transport measurement. International Association of Hydrologic Sciences Publication, +--, Oxfordshire, United Kingdom.
Nishida, I., Tatekawa, M. and Koyama, K. (+33/) :E#ect of organic matter applications for thevegetative cultivation on reclaimed ﬁeld. Bull.
Nara Agri. Expt.Sta., ,0 : /-ῌ0* (in Japanesewith an English summary).
Reinking, L. (,**+) : ImageJ version +.,.o, updated
August ,*, ,**+. http : //rsb.info.nih.gov/ij/
docs/pdfs/ImageJ.pdf (accessed ,**1ῌ+,ῌ+-).
Ruan, H., Ahuja, L.R., Green, T.R. and Benjamin, J.
G. (,**+) : Residue cover and surface-sealing : Evaluating Inﬂuence of Di#erent Cover Materials on Runo# and Sediment Loss from
Bare Upland Soil using Laboratory Rainfall Simulator
e#ects on inﬁltration : Numerical simulations
for ﬁeld applications. Soil Sci. Soc. Am. J., 0/ :2/-ῌ20+.
Rural Development Bureau, The Ministry of Agriculture, Forestry and Fisheries of Japan(MAFF) (,**0) : A planning - farm ﬁeld improvement (upland) - In Design criteria forland reform project program, draft revisions(in Japanese). http : //www.ma#.go.jp/www/public/cont/,**0*+*.seisaku_+e.pdf (accessed,**1ῌ*3ῌ+3).
Shimizu, N. (,**/) : Measures of support to promotea system for utilization of organic resources
A case of livestock manure utilization. Tech.
Rep. Natl. Inst. Rural Eng. Japan, ,*- : .1ῌ/0.
Singer, M. J. and Blackard, J. (+311) : Evaluation ofwild oat straw as a soil erosion retardant using
simulated rainfall. Agron. J., 03 : 2++ῌ2+..
Singer, M. J. and Walker, P.H. (+32-) : Rainfallruno# in soil erosion with simulated rainfall,
overland ﬂow and cover. Aust. J. Soil Res., ,+ :+*3ῌ+,,.
The Ministry of Agriculture, Forestry and Fish-

eries of Japan (MAFF) (,**,) : Chapter III :Section , The roles of farming, forestry andﬁshing villages in making sustainable use of
biomass. In Annual report on food, agriculture
and rural areas in Japan FY ,**, (summary).
http : //www.ma#.go.jp/hakusyo/kaigai/,**,
a_rep.pdf (accessed ,**1ῌ+,ῌ+-).
Vadas, P.A., Meisinger, J. J., Sikora, L. J., McMurtry,
J.P. and Sefton, A.E. (,**.) : E#ect of poultry
diet on phosphorus in runo# from soils
amended with poultry manure and compost. J.
Environ. Qual., -- : +2./ῌ+2/..
Watanabe, T. and Kawabata, T. (+32*) : E#ects offarmyard manure on soil-erosion and soil fertility of an inclined ﬁeld. Bull. FUKUI Agr.
Exp. Sta., +1 : /+ῌ/3 (in Japanese with an English summary).
Yamamoto, H., Osozawa, S., Ishihara, A. andHanano, Y. (+33/) : E#ects of straw mulch on
soil erosion from steep slopes in Shikoku,
Japan. Soil Phys. Cond. Plant Growth Jpn., 1+ :.+ῌ.0 (in Japanese with an English abstract).

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