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Pedosphere 20(6): 736746, 2010

ISSN 1002-0160/CN 32-1315/P

c 2010 Soil Science Society of China

Published by Elsevier Limited and Science Press

Effect of Soil Erosion on Soil Properties and Crop Yields

on Slopes in the Sichuan Basin, China1

SU Zheng-An1,2, ZHANG Jian-Hui1,2 and NIE Xiao-Jun1,2

1Institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Conservancy,Chengdu 610041 (China)2Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China)

(Received January 7, 2010; revised June 2, 2010)

ABSTRACT

Roles of tillage erosion and water erosion in the development of within-field spatial variation of surface soil properties

and soil degradation and their contributions to the reduction of crop yields were studied on three linear slopes in the

Sichuan Basin, southwestern China. Tillage erosion was found to be the dominant erosion process at upper slope positions

of each linear slope and on the whole short slope (20 m). On the long slope (110 m) and medium slope (40 m), water

erosion was the dominant erosion process. Soil organic matter and soil nutrients in the tillage layer were significantly

related to slope length and 137Cs inventories on the long slope; however, there was no significant correlation among them

on the short slope, suggesting that water erosion lowered soil quality by transporting SOM and surface soil nutrients

selectively from the upper to lower slope positions, while tillage erosion transported soil materials unselectively. On the

medium slope, SOM, total N, and available N in the tillage layer were correlated with slope length and the other properties

were distributed evenly on the slope, indicating that water erosion on this slope was still the dominant soil redistribution

process. Similar patterns were found for the responses of grain yield, aboveground biomass, and harvest index for slopes.

These results indicated that tillage erosion was a major cause for soil degradation and grain yield reduction on the linear

slopes because it resulted in displacement of the tillage layer soil required for maintaining soil quality and plant growth.

Key Words: 137Cs inventory, linear slope, soil degradation, tillage erosion, water erosion

Citation: Su, Z. A., Zhang, J. H. and Nie, X. J. 2010. Effect of soil erosion on soil properties and crop yields on slopes

in the Sichuan Basin, China. Pedosphere. 20(6): 736746.

INTRODUCTION

There is a growing recognition that tillage erosion plays an important role in the redistribution of

soil within a slope landscape (Quine et al., 1999; Van Muysen et al., 1999; Quine and Zhang, 2002;

Kosmas et al., 2001; Nassen et al., 2002; Dercon et al., 2003; Van Oost et al., 2003, 2004; De Alba et

al., 2004; Li et al., 2004; Zhang et al., 2004a, b, 2006; Malo et al., 2005; Papiernik et al., 2005; Liet al.,

2007; Zhenget al., 2007). Goverset al. (1999) reported that the observed patterns of soil redistributionin fields did not agree with the predictions of standard water erosion models. Furthermore, the spatial

signatures of water erosion and tillage erosion are fundamentally different: soil loss by tillage will be

most intense on landscape positions where water erosion is minimal (i.e., convexities and near upslope

field borders), while soil accumulation by tillage often occurs in a place where water erosion is maximal

(e.g., hollows where overland flow concentrates).

As early as 1937, a study by Puhr and Olson (1937) reported the impacts of 50 years of cultivation

on selected soil chemical and physical properties in a few selected South Dakota soils. However, there

had been virtually no systematic study of tillage translocation and erosion until the first attempts were

1Supported by the National Natural Science Foundation of China (No. 40771027), the National Key Technology

R&D Program of China (No. 2008BAD98B04) and the National Basic Research Program (973 Program) of China

(No. 2007CB407206).2Corresponding author. E-mail: [email protected].

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EROSION EFFECT ON SOIL PROPERTIES AND CROP YIELDS 737

made in the 1980s and early 1990s (Goverset al., 1999). Since then, the importance of tillage erosion and

effect of tillage erosion on soil properties and grain yields have been demonstrated all over the world. Da

Silva et al. (1999) reported that tillage erosion, in the long term, altered soil profile and consequently

affected soil water-holding capacity, nutrient availability, and organic matter (SOM) reserve, and grainyields. Several studies prove that tillage erosion increases soil variability and degradation of surface soil

quality on convex slope positions, as well as spatial variability of crop production (Schumacher et al.,

1999; Kosmas et al., 2001; Papiernik et al., 2005). Kosmas et al. (2001) reported that tillage erosion

affected chemical properties of soils mainly in three important ways: loss in soil organic matter, loss in

soil nutrients, and exposure of subsoil with low fertility or high acidity. According to Quine and Zhang

(2002), tillage erosion was the dominant soil redistribution process and correlated closely with the soil

properties and grain yields, suggesting that soil redistribution by tillage was a major contributor to the

spatial variation in soil properties and crop production. In linear slope landscapes (Asia and Africa),

animal-drawn plough and manual hoeing was considered the primary tillage tool and also created tillage

erosion on hillslopes, with significant effect on soil degradation and grain yields (Thapa et al., 1999;

Turkelboom et al., 1999; Nyssen et al., 2002; Li et al., 2004; Zhang et al., 2004a, b, 2006).Although studies by Zhanget al.(2004a, b, 2006) and Ni and Zhang (2007) have clearly demonstrated

that runoff water is not the only erosive factor and tillage erosion has also greatly contributed to total

soil erosion and would be more severe than water erosion in some landscape positions in the Sichuan

Basin, China, these studies focused on the quantities of tillage erosion and impacts of tillage erosion

on soil quality, without addressing tillage erosion effects on grain yields. It is, therefore, urgent to

evaluate soil erosion and erosion-induced depletion of soil nutrients and reduction of grain yield, so as

to understand the process of soil degradation due to erosion and to establish sustainable ecosystems

and soil management practices to prevent the soils from further degradation or to facilitate restoration.

This study initiated to relate caesium-137 derived soil erosion rates and patterns to observed spatial

variations in surface soil properties and crop productivity, with specific objectives of: 1) to apply the137Cs technique to assess contemporary soil erosion and deposition patterns under a long-term cultivation

in the Sichuan Basin; 2) to investigate the spatial variation in surface soil properties and crop yields; and

3) to analyze the relationships between the contemporary (137Cs-derived) soil redistribution patterns

with surface soil properties and grain yields.

MATERIALS AND METHODS

The study area is located in Jianyang County (30 04 2830 39 00 N, 103 11 34104 53

36 E, 400587 m above sea level), Sichuan Province, southwestern China. This area is typical of hilly

areas of Sichuan and it has a humid sub-tropical climate, with a mean annual temperature of 17 C

and a mean annual precipitation of 960 mm. The erosive rainfalls between May and September account

for 62.3% of annual precipitation (Zhang et al., 2008). The land use in the area is characterized by dry

land cultivation where wheat (Triticum aestivumL.) makes up a large part of the crop rotation with

corn (Zea mays L.), sweet potato (Ipomoea batatas (L.) Lam.), groundnut (Arachis hypogaeaL.), and

rape (Brassica napus L.). After harvesting corn and sweet potato or groundnut, the fields are tilled

with a hoe during the late summer or early fall. Local farmers till their land one time at this stage in

order to improve seed bed conditions for seeding of winter wheat or rape as the next crop. Information

provided by farmers in the study area indicates that the fields have been cultivated for at least 100

years. The soil in the study area derived from purple mudstone and sandstone of Jurassic Age enriched

in CaCO3 (Tang et al., 1984), with a pH of 8 and a clay content of 250400 g kg1, is classified as a

Regosol according to the FAO soil taxonomy (FAO, 1988) and as a clay loam according to the USDA

soil taxonomy (Soil Survey Staff, 1996). When cultivated, the soil is highly susceptible to erosion and

the area represents one of the most severely eroded regions in China.

Most of the hillslopes in the study area have been dissected into slope segments and terraces; there-

fore, they are linear slopes and different slope gradients have evolved during the long-term agricultural

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738 Z. A. SUet al.

practice. In rare cases, relatively leveled surfaces on terraces have been created by large amounts of

engineering work. In the context of this study, however, attention was given to different lengths of linear

slopes with slope gradients between 9.1% and 25.1%. In the study area, hoeing is the dominant tillage

practice due to small patches of fields and steep hillslopes. Farmers are accustomed to till from thebottom of the field and gradually moving up the slope. The upper parts of the slope segments in the

study area are characterized by a thin soil layer, underlain by rock stratum, whereas thick soil layers

are found in the lower parts of the slope.

Soil sampling was carried out in March of 2006 (dry season) on three slopes, which are located

approximately 500 m apart each other. No systematic variations in soil texture of the Ap or the B

horizons were observed among the three slopes. The first slope is a long hillslope with a gradient

of 10.1% and a slope length of 110 m (Ge et al., 2007). The slope is steep in the upper and middle

parts and gentle in the lower part. The second is a medium slope with a slope gradient of 9.1% and a

slope length of 40 m. The third is a short slope with a slope gradient of 25.1% and a slope length of

20 m. The coordinates and elevation of each sampling point were measured using a differential global

positioning system (DGPS) with horizontal accuracy of a few centimeters. Soil samples were collectedat 5 m intervals along the slope transect using a 6.8 cm diameter hand-operated core sampler. For each

sampling point, two cores were collected along the soil profile to a depth depending on soil thickness ( i.e.,

down to bedrock) and then bulked to make a composite sample. In cases where a subsurface horizon B

was distinguishable below the plow layer (Ap), the two horizons were sampled separately. Soil samples

were air-dried, crushed, and passed through a 2 mm-mesh sieve. Coarse materials such as gravels and

roots were removed. Samples of the < 2 mm fraction were weighted and used for all subsequent analyses.

A subsample of the total core was then prepared for 137Cs analysis by carefully mixing a/(a+ b) kg

sample of the < 2 mm particle-size fraction from the plow layer (Ap) with b/(a+b) kg sample of the

< 2 mm particle-size fraction of the sub-plow layer (B), where a and b are the weights of the samples

from Ap and B horizons, respectively. This subsample was then packed into a plastic beaker, and 137Cs

activity was measured using a hyperpure lithium-drifted germanium detector (ORTEC, USA) coupled

with a Nuclear Data 6700 multichannel gamma-ray spectrophotometer with counting time from 40 000

to 60 000 s. The relative errors of test results were lower than 5%. The inventories of137Cs were originally

expressed on a unit mass basis (Bq kg1) and were then converted to an area basis (Bq m2) using the

total mass of the bulked core sample.

Soil physical and chemical properties were determined according to the regular analysis methods.

Soil particle-size fractions were determined by the pipette method following H2O2 treatment to de-

stroy organic matter and subsequent dispersion of soil suspensions by Na hexametaphosphate (ISSCAS,

1978). Soil bulk densities were determined using oven-dried weight and sample volume. Soil organic

matter was determined using wet oxidation with K2Cr2O7. Total N was measured by the classical Kjel-

dahl digestion method. The determination of total P and K was carried out using the NaOH digestion

method. Available N was measured using NaOH extraction and distilling. Extractable P and K were

determined using NaOH digestion and ammonia acetic extraction, respectively (Liu, 1996).Wheat grain yield and aboveground biomass were measured at the end of the growth period at 5 m

intervals along the transects of the slopes, using a reaping hook from two plots 1 m 2 each. The grains

and total biomass were weighed after wheat was dried in the laboratory. Harvest index was calculated

as the grain yield as a percentage of the aboveground biomass.

The efficient 137Cs reference inventory is used to eliminate impacts of 137Cs surface enrichment

during nuclear explosion period on the assessment of soil losses on cultivated sloping land (Zhang et al.,

2000). The efficient 137Cs reference inventory (Ae, Bq m2) is expressed as:

Ae= Ao(1 RI) (1)

where Ao is the 137Cs reference inventory (Bq m2) and RI is the runoff index. Using a runoff index

of 0.25 as measured by Lei et al. (2003) and a local 137Cs reference inventory of 1 927 Bq m2 from

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Zhang et al. (2004c), the efficient 137Cs reference inventory was calculated to be 1 445 Bq m2 (Zhang

et al., 2006). For an eroded site where a total 137Cs inventory (A, Bq m2) is less than the reference

inventory at year t (years), soil erosion rates can be expressed as (Zhang et al., 1990):

= 10dB

P

1

1

X

100

1/(t1963) (2)

where is the mean annual soil erosion rate (t ha1 year1), d the sampling depth (m), B the bulk

density of soil (kg m3),Xthe percentage reduction in total 137Cs inventory (X= (AeA)/Ae 100),

andP the particle size correction factor. In accordance with earlier study results in this area (Zhanget

al., 2004a, b), tillage erosion rates increase with increasing slope gradient and are inversely proportional

to the slope length:

R= (k3+k4S) 10/Ld (3)

whereR is the tillage erosion rate (t ha1 per tillage pass),k3 andk4 are the soil transport coefficients

(kg m1 per tillage pass), Sis the slope gradient (m m1), and Ld is the downslope parcel length (m).Simple linear regression analysis (Pearson product-moment correlation) was carried out to determine

the relationships between SOM, total N, total K, total P, available N, extractable K, extractable P, grain

yield, aboveground biomass, and 137Cs inventory. Analysis of variance was used to test the significance

of differences found between different positions of a slope. All statistical analyses were carried out using

SPSS software (version 11.5).

RESULTS AND DISCUSSION

Soil redistribution

For the long slope (Fig. 1a), 137Cs inventories were found to increase from the upper to lower slope

positions, being the lowest at the top and the highest at the foot position (100110 m), with the latterbeing 2 times higher than that of the former. On the medium slope (Fig. 1b), 137Cs inventories ranged

from a low value of 823.6 Bq m2 at the upper slope positions (05 m) to a high value of 1 386.8 Bq m2

at the foot slope positions (3540 m). Along the short slope transect, 137Cs inventories also increased

from the top to foot slope positions (Fig. 1c), with a 57.1% increase at the foot slope position compared

to that at the top of the slope. These suggest that soil loss occurred at the upper slope positions and soil

accumulation at the foot slope positions. This pattern of soil redistribution, characterized by soil loss

from the upper slope positions and deposition at the lower slope positions and the resultant increase in

soil depth from the upper to lower slope positions, is typical of tillage erosion in the study area (Zhang

et al., 2004a, b, 2006; Ge et al., 2007; Ni and Zhang, 2007). This result is also consistent with those of

the studies by Lobb and Kachanoski (1999), Van Muysenet al.(1999), Kosmasset al.(2001), Quine and

Fig. 1 Distribution of137Cs inventory a long the transects of a long slope (a), a medium slope (b), and a short slope (c).

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740 Z. A. SUet al.

Zhang (2002), Van Oostet al.(2003), Liet al.(2004), Maloet al.(2005), and Papierniket al.(2005). Fur-

thermore, the standard water erosion models show that water erosion is minimal near upslope field

borders (Govers et al., 1999). Therefore, the most serious erosion occurred at the upper slope position,

suggesting that tillage erosion redistributed soil in amounts, which decreased the effect of water erosionat that position on linear slopes.

The tillage erosion rates were much higher on the short slope than on the two longer slopes (Table

I). Tillage transport coefficients, k3 and k4, in the study area reach 30.7 and 141.3 kg m1 per tillage

pass, respectively (Zhang et al., 2004a). Based on one major tillage operation per year in the study

area, tillage erosion rates were estimated at 4.1, 10.9, and 33.1 t ha1 year1 for the long slope, medium

slope, and short slope, respectively (Table I). Tillage erosion rates being 7 times higher on the short

slope than on the long slope and 2 times higher on the short slope than on the medium slope suggested

that tillage erosion was more pronounced on short linear slopes. Compared with the contribution of

tillage erosion to the total erosion on the long and medium slopes (11.8% and 27.3%, respectively), the

contribution of tillage erosion was great (52.1%) on the short slope, showing that tillage erosion was the

dominant erosion process on the short slope, whereas water erosion was the dominant erosion processon the long slope and medium slope.

TABLE I

Lengths, gradients, 137Cs inventories, and erosion rates of the different slopes studied

Item Long slope Medium slope Short slope

Slope length (m) 110 40 20

Number of samples 12 9 5

Slope gradient (%) 10.1 9.1 25.1

Mean 137Cs inventory (Bq m2) 946.5289.54 1071.9773.27 758.30312.70

Tillage erosion rate (t ha1 year1) 4.1 10.9 33.1

Total erosion rate (t ha1 year1) 34.8 40.0 63.6

Contribution of tillage erosion to total erosion (%) 11.8 27.3 52.1

The< 0.02 mm particle-size fraction distribution of the tillage layer also demonstrated that tillage

erosion played a key role on the short slope, whereas water erosion was the dominant erosion process

on the long and medium slopes (Fig. 2). The< 0.02 mm particle size fraction in the tillage layer gra-

dually increased from top to bottom of the long slope and was negatively correlated with the elevation

(r = 0.80, P = 0.02, Fig. 2c). In contrast, the

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TABLE II

Descriptive statistics of tillage layer soil properties and crop properties on different slops studied

Slope Soil or crop Propertya) n Minimum Maximum Mean SDb) C.V.c)

%

Long Soil

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742 Z. A. SUet al.

slope, the tillage erosion accounted for more than 50% of the total erosion, indicating that tillage erosion

was a dominant erosion process within the short linear slope. Tillage erosion unselectively transported

soil materials downslope and thus induced insignificant spatial variations within the short slope, whereas

water erosion selectively transported soil fine particles, which had relatively more SOM, total N, andavailable N, and consequently caused notable spatial variations in these elements. Therefore, within

different landscapes, i.e., short, medium, and long linear slopes, different dominant processes of soil

redistribution caused different spatial variations in surface soil properties. Zhanget al. (2006), Ni and

Zhang (2007), and Geet al. (2007) reported similar results, but Quine and Zhang (2002) advocated that

soil redistribution by tillage was the most important process contributing to within-field soil variability

and that higher soil variability could be expected to develop in complex landscapes due to continuous

tillage operation. These differences could be explained by different landscapes (linear slope and complex

landscapes), and different types of tillage operations (downslope vs. upslope and downslope) and tillage

tools (hoe vs. tractor).

Fig. 3 Distribution of soil organic matter (SOM) and total N (TN) in the tillage layer on the long slope (SOMvs. slopelength: r = 0.71, P = 0.009; TN vs. slope length: r = 0.85, P = 0.001).

Fig. 4 Distribution of soil available N (AN), extractable P (EP), and extractable K (EK) in the tillage layer on the longslope.

Fig. 5 Distribution of soil organic matter (SOM), total N, and available N in the tillage layer on the medium slope.

Relationships between soil properties and 137Cs inventories

For the long slope, positive correlations between 137Cs inventories and surface soil properties were

found (Fig. 6), being significant at P < 0.01 with r values of 0.79, 0.87, 0.96, 0.73, and 0.90. On the

medium slope, available N and extractable K in the tillage layer were found to be systematically related

to 137Cs inventories (Fig. 7). However, no significant correlations between 137Cs inventories and surface

soil properties were found for the short slope, implying that SOM and soil nutrients in the tillage layer

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did not change significantly. According to Zhang et al. (2006) and Ge et al. (2007), the < 0.02 and

< 0.002 mm particle-size fractions were significantly correlated with total N, available N, extractable

P, extractable K, and SOM, and the fine particles were selectively transported by runoff from upslope

to downslope on the long slope. In contrast, tillage erosion transported soil materials from upslope todownslope unselectively. Therefore, the differences in the distribution of surface soil properties between

different landscapes were attributed to the differences in soil erosion process; tillage erosion was mainly

responsible for symmetrical distribution of surface soil properties at each position on the short slope,

whereas water erosion played a primary role in higher soil SOM and soil nutrients in the tillage layer at

the downslope positions on the long slope.

Fig. 6 Distribution of surface soil propertiesvs. caesium-137 (137Cs) inventories on the long slope. SOM = soil organicmatter.

Fig. 7 Distribution of available N (AN) and extractable K (EK) in the tillage layervs. caesium-137 (137Cs) inventories on

the medium slope.

Relationships between crop properties and 137Cs inventories

On the long slope, the mean grain yield distribution (Table III) was similar to that of 137Cs inven-

tories and soil redistribution by tillage erosion and water erosion (Fig. 1a). Mean grain yield and mean

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744 Z. A. SUet al.

aboveground biomass were found to be the lowest at the upper slope positions on the long slope where

the tillage erosion rate was the highest, whereas at the lower slope positions where soil aggradations were

identified, the grain yield and aboveground biomass were higher. On the medium slope, the grain yield

and aboveground biomass had high values at the foot slope positions where soil aggradations occurred,with no significant differences observed at the other slope positions. On the short slope, the grain yield

and aboveground biomass showed a gradual downslope increase.

The 137Cs inventory ratio of the upper slope position to the foot slope position showed a similar trend

to that for the grain yield and aboveground biomass. However, the value of the 137Cs inventory ratio was

obviously lower than those of the grain yield and aboveground biomass. On the long slope, the ratio was

0.41 for 137Cs inventory and 0.69 and 0.76 for the grain yield and aboveground biomass, respectively. On

the medium and short slopes, the 137Cs inventory ratios were 0.59 and 0.48, respectively, as compared

to the grain yield ratios of 0.89 (medium slope) and 0.82 (short slope) and the aboveground biomass

ratios of 0.88 (medium slope) and 0.93 (short slope). These indicated that the relationship between soil

redistribution and crop production was not a simple one in this field and therefore other factors must

be taken into account, integrating soil, water, plant, and air factors (Quine and Zhang, 2002).

TABLE III

Mean grain yield, mean aboveground biomass, and harvest index of wheat on the different slopes studied

Slope Position n Mean grain yield Mean aboveground biomass Harvest index

kg m2

Long slope Upper 6 0.400.01 1.040.11 0.38

Middle 8 0.430.04 1.240.13 0.35

Lower 6 0.540.02 1.210.06 0.45

Foot 4 0.580.01 1.360.01 0.42

Medium slope Upper 4 0.520.01 1.350.03 0.39

Middle 6 0.500.07 1.200.09 0.42

Lower 4 0.510.01 1.270.01 0.40

Foot 4 0.580.04 1.540.13 0.38Short slope Upper 2 0.480.01 1.260.03 0.38

Middle 2 0.560.11 1.380.27 0.41

Lower 2 0.610.11 1.450.34 0.42

Foot 2 0.580.07 1.350.21 0.43

On the long slope, the harvest index of wheat was found to be lower than 0.40 at the upper and

middle slope positions, greater than 0.40 at the other slope positions in each of the slopes. On the

medium slope, the harvest index was also lower than 0.40 at the upper slope positions, but was greater

than 0.40 at the middle and lower positions. It is interesting to note that the harvest index was lower

than 0.40 at the foot slope position of the medium slope, suggesting that the grain yield did not increase

as much as the aboveground biomass at that slope position. However, on the short slope, the harvest

index of wheat was lower than 0.40 only at the upper slope positions, and greater than 0.4 at allother slope positions. According to Liu et al. (1991), the harvest index of wheat averages 0.35 with a

maximum of 0.40 and a minimum of 0.30. This indicated that soil redistribution due to tillage erosion

and water erosion played an important role in redistributing nutrients and altering grain yields through

changing the depth of soil layer and surface soil properties. Therefore, tillage erosion could be a major

contributor to variation in crop properties in some landscapes, for instance the short linear slope, and

some landscape positions, i.e., upper slope positions of the long slope and medium slope.

CONCLUSIONS

Caesium-137 data indicated that soil erosion occurred at upper slope positions and deposition oc-

curred at the lower slope positions on the long slope, medium slope, and short slope. Further analysis of

soil particle-size fractions suggested that tillage erosion played an important role in the transfer of soil

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materials from the upper to lower slope positions. On the long slope and medium slope, water erosion

was suggested to be the dominant erosion process, while tillage erosion was the dominant erosion process

on the short slope. Surface soil properties were strongly related to 137Cs inventories and slope length

on the long slope, showing that soil redistribution determined the variation of surface soil properties onthis slope. On the short slope, 137Cs inventories were found to be correlated with slope length; however,

surface soil properties (particle-size fraction) were distributed evenly on the slope, suggesting that soil

redistribution by tillage was the most important process contributing to within-field soil variability.

On the medium slope, some surface soil properties, i.e., < 0.02 mm particle-size fraction, available

N, and extractable K, were found to be related to 137Cs inventories and other surface soil properties

were stochastically distributed, suggesting that water erosion was still the dominant soil redistribution

process. These results indicated that attention must be given to impacts of tillage erosion on soil degra-

dation within short slope landscapes, particularly at the upper slope positions. Water erosion selectively

transported soil materials, which could result in higher SOM, clay, and nutrients in the tillage layer at

the lower slope positions, while soil materials were relocated unselectively by tillage erosion, resulting

in inappreciable changes in soil chemical and physical composition. Therefore, water erosion loweredsoil quality by transporting surface soil nutrients and SOM selectively from the upper to lower slope

positions. Grain yields and aboveground biomass were found to increase from the upper to lower slope

positions in each slope. However, since the relationship between crop properties and erosion is complex,

more data (i.e., rainfall and soil moisture) for years with different weather and landform conditions are

required to explore these trends fully. It could be concluded that tillage erosion was a major cause for

soil degradation and grain yield reduction in the linear slopes because it resulted in displacement of

tillage layer soil required for maintaining soil quality and plant growth.

REFERENCES

Da Silva, J., Rafael, M. and Soares, J. M. C. N. 1999. Soil tillage and soil quality. In Proceedings of the Second

International Symposium on Tillage Erosion and Tillage Translocation, Leuven, Belgium, April. Abstracts. CatholicUniversity of Leuven, Belgium. p. 22.

De Alba, S., Lindstrom, M., Schumacher, T. E. and Malo, D. D. 2004. Soil landscape evolution due to soil redistribution

by tillage: a new conceptual model of soil catena evolution in agricultural landscapes. Catena. 58: 77100.

Dercon, G., Deckers, J., Govers, G., Poesen, J., Sanchez, H., Vanegas, R., Ramrez, M. and Loaiza, G. 2003. Spatial

variability in soil properties on slow-forming terraces in the Andes region of Ecuador. Soil Till. Res. 72: 3141.

FAO. 1988. Soil Map of the World. Revised legend. World Soil Resources Report 60. FAO, Rome.

Govers, G., Lobb, D. A. and Quine, T. A. 1999. Tillage erosion and translocation: emergence of a new paradigm in soil

erosion research. Soil Till. Res. 51: 167174.

Ge, F. L., Zhang, J. H., Su, Z. A. and Nie, X. J. 2007. Response of changes in soil nutrients to soil erosion on a purple

soil of cultivated sloping land. Acta Ecol. Sin. 27: 459463.

Institute of Soil Science, Chinese Academy of Sciences (ISSCAS). 1978. Analysis of Soil Physics and Chemistry (in

Chinese). Shanghai Science and Technology Press, Shanghai.

Kosmas, C., Gerontidis, S., Marathianou, M., Detsisa, B., Zafiriou, T., Van Muysen, W., Govers, G., Quine, T. A. and

Vanoost, K. 2001. The effects of tillage displaced soil on soil properties and wheat biomass. Soil Till. Res. 58: 3144.

Lei, X. Z., Cao, S. Y., Dai, H. L. and Dai, Y. B. 2003. Study on the benefits of sediment reduction and water resources

regulation by Changzhi Project in the Sichuan Basin. J. Sediment Res. (in Chinese). 5: 5258.

Li, S., Lobb, D. A., Lindstrom, M. J. and Farenhorst, A. 2007. Tillage and water erosion on different landscapes in

the northern North American Great Plains evaluated using 137Cs technique and soil erosion models. Catena. 70:

493505.

Li, Y., Tian, G., Lindstrom, M. J. and Bork, H. R. 2004. Variation of surface soil quality parameters by intense-donkey-

drawn tillage on steep slope. Soil Sci. Soc. Am. J. 68: 907913.

Liu, G. S. 1996. Soil Physical and Chemical Analysis and Description of Soil Profiles (in Chinese). Chinese Standard

Press, Beijing.

Liu, F. R., Jiang, N. S. and Lu, M. L. 1991. Dictionary of Modern Rural Economy (in Chinese). Liaoning Peoples

Publishing House, Shenyang.

Lobb, D. A. and Kachanoski, R. G. 1999. Modelling tillage translocation using step, linear-plateau and exponential

functions. Soil Till. Res. 51: 317330.

Malo, D. D., Schumacher, T. E. and Doolittle J. J. 2005. Long-term cultivation impacts on selected soil properties in the

northern Great Plains. Soil Till. Res. 81: 277291.

8/12/2019 1-s2.0-S1002016010600641-main

11/11

746 Z. A. SUet al.

Ni, S. J. and Zhang, J. H. 2007. Variation of chemical properties as affected by soil erosion on hillslopes and terraces.

Eur. J. Soil Sci. 58: 12851292.

Nyssen, J., Poesen, J., Moeyersons, J., Lavrysen, E., Haile, M. and Deckers, J. 2002. Spatial distribution of rock fragments

in cultivated soils in northern Ethiopia as affected by lateral and vertical displacement processes. Geomorphology.43: 116.

Papiernik, S. K., Lindstrom, M. J., Schumacher, J. A., Farenhorst, A., Stephans, K. D., Schumacher, T. E. and Lobb, D.

A. 2005. Variation in soil properties and grain yield across an eroded prairie landscape.J. Soil Water Conserv. 60:

388395.

Puhr, L. F. and Olson, O. 1937. A preliminary Study of the Effect of Cultivation on Certain Chemical and Physical

Properties of Some South Dakota Soils. AES Bull. 314. South Dakota State College, Brookings.

Quine, T. A., Walling, D. E., Chakela, Q. K., Mandiringana, O. T. and Zhang, X. 1999. Rates and patterns of tillage and

water erosion on terraces and contour strips: evidence from caesium-137 measurements. Catena. 36: 115142.

Quine, T. A. and Zhang, Y. 2002. An investigation of spatial variation in soil erosion, soil properties, and crop production

within an agricultural field in Devon, United Kingdom. J. Soil Water Conserv. 57: 5565.

Schumacher, T. E., Lindstrom, M. J., Schumacher, J. A. and Lemme, G. D. 1999. Modeling spatial variation in productivity

due to tillage and water erosion. Soil Till. Res. 51: 331339.

Soil Survey Staff. 1996. Keys to Soil Taxonomy. 7th edition. USDA Natural Resource Conservation Service, U.S.

Government Printing Office, Washington, D.C.

Tang, S. J., Sun, D. J., Luo, Y. F., Zhou, D. H., He, R. and Mao, J. H. 1984. The fertility of purple soil in relation to thecharacteristics of parent material in the Sichuan Basin. Acta Pedol. Sin. (in Chinese). 21: 123133.

Thapa, D., Cassel, D. and Garrity, D. 1999. Assessment of tillage erosion rates on steepland Oxisols in the humid tropics

using granite rocks. Soil Till. Res. 51: 233243.

Turkelboom, F., Poesen, J., Ohler, I. and Ongprasert, S. 1999. Reassessment of tillage erosion rates by manual tillage on

steep slopes in northern Thailand. Soil Till. Res. 51: 245259.

Van Muysen, W., Govers, G., Bergkamp, G., Roxo, M. and Poesen, J. 1999. Measurement and modelling of the effects of

initial soil conditions and slope gradient on soil translocation by tillage. Soil Till. Res. 51: 303316.

Van Oost, K., Govers, G., Quine, T. A. and Heckrath, G. 2004. Comments on managing soil carbon. Science. 305: 1567.

Van Oost, K., Govers, G. and Van Muysen, W. 2003. A process-based conversion model for caesium-137 derived erosion

rates on agricultural land: an integrated spatial approach. Earth Surf. Proc. Landforms. 28: 187207.

Zhang, J. H., Frielinghaus, M., Tian, G. and Lobb, D. A. 2004a. Ridge and contour tillage effects on soil erosion from

steep hillslopes in the Sichuan Basin, China. J. Soil Water Conserv. 59: 277283.

Zhang, J. H., Lobb, D. A., Li, Y. and Liu, G. C. 2004b. Assessment of tillage translocation and tillage erosion by hoeing

on the steep land in hilly areas of Sichuan, China. Soil Till. Res. 75: 99107.

Zhang, J. H., Quine, T. A., Ni, S. J. and Ge, F. L. 2006. Stocks and dynamics of SOC in relation to soil redistribution by

water and tillage erosion. Glob. Change Biol. 12: 18341841.

Zhang, J. H., Su, Z. A. and Liu, G. C. 2008. Effects of terracing and agroforestry on soil and water loss in hilly areas of

the Sichuan Basin, China. J. Mt. Sci. 5: 241248.

Zhang, X. B., He, X. B., Wen, A. B., Walling, D. E., Feng, M. Y. and Zou, X. 2004c. Sediment source identification by

using 137Cs and 210Pb radionuclides in a small catchment of the Hilly Sichuan Basin, China. Chinese Sci. Bull. 49:

19531957.

Zhang, X. B., Higgitt, D. L. and Walling, D. E. 1990. A preliminary assessment of the potential for using caesium-137 to

estimate rates of soil erosion in the Loess Plateau of China. Hydrol. Sci. J. 35: 267276.

Zhang, X., Quine, T. A., Walling, D. E. and Wen, A. B. 2000. A study of soil erosion on a steep cultivated slope in the

Mt. Gongga Region near Luding, Sichuan, China, using the 137Cs technique. Acta Geol. Hispanica. 35: 229238.

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