ABSTRACT Topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are referred to microtopographies. In hilly

mountainous regions, the redistribution of water and soil materials caused by microtopography is the main factor affecting the spatial heterogeneity of soil and the utilization of land

resources. In this study, the influence of microtopography on pedogenesis was investigated using soil samples formed from mudstones with lacustrine facies deposition in the middle of the

Sichuan Basin. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physicochemical, and geochemical

hillslope, weathered materials were transported away by gravity and surface erosion, exposing new rocks. As a result, soil development in these areas was relatively weak. In flat areas such

as the footslope and toeslope with sufficient water conditions, the addition of weathered components and the prolonged contact between water, soil, and sediment led to further chemical

weathering, resulting in highly developed characteristics. Microtopography may influence physicochemical properties, chemical weathering, and redistribution of water and materials, causing

variations in pedogenic characteristics at different slope positions. SIMILAR CONTENT BEING VIEWED BY OTHERS RESPONSE OF SOIL PARTICLES AROUND BEDROCK OUTCROPS TO SORTING OF ROCK SURFACE

FLOW DERIVED OUTCROPS IN A ROCKY DESERTIFICATION AREA Article Open access 29 July 2024 SOIL QUALITY CHANGES IN THE HORQIN SANDY AREA UNDER DIFFERENT ECOLOGICAL RESTORATION PATTERNS Article

Open access 15 March 2025 MINERALOGICAL COMPOSITIONS OF SOILS UNDER THREE GEOLOGICAL FORMATIONS IN SOME PARTS OF OGUN STATE, NIGERIA AND THEIR AGRICULTURAL POTENTIALS Article Open access 22

March 2024 INTRODUCTION Soil, as an independent natural body, sustains the lives and reproduction of various creatures on the land surface, while also developing and changing under the

control of the soil-forming environment. Pedogenesis refers to the evolution from the profile scale to the regional scale, encompassing significant changes in the soil under physical,

chemical, or biological conditions1. Among the five major soil forming factors, topography does not contribute new substances to the soil formation process. However, it strongly influences

the physicochemical properties of soils by affecting the redistribution of water, soil materials, and nutrients2,3,4. The variations in water characteristics, combined with intense erosion,

impact the redistribution of soil materials and elements during soil formation. This ultimately results in variations in the level of soil development across different parts of the

terrain5,6,7,8,9. Therefore, soils on steep terrain tend to have rather shallow, poorly developed profiles compared to soils on nearby, more level sites10. Furthermore, the large topographic

relief also results in orographic rain and temperature variations, which can affect the water and temperature conditions, as well as vegetation distribution, eventually impacting

pedogenesis. Small-scale topographic changes are defined as microtopographies. Microtopography refers to the concept that are relative to macrotopography, with amplitudes markedly smaller

than the hillslope or basin scales11. Compared to microtopography, the greater variation of climate conditions and parent material due to large-scale topography often results in spatial

heterogeneity of soil types. For instance, in the subtropical mountains of southeast China, the soils exhibit a vertical zonal distribution with yellow soil, yellow–red soil, and red soil

from the summit to the footslope of the mountains12. However, in a small-scale toposequence, the differences between soils are primarily a result of topographic effects. This is because the

soils in the sequence typically share the same parent material and have similar conditions such as climate, vegetation, and time10,13. A series of toposequences derived from granite,

sandstone-gneiss, limestone, and slate have shown that topography plays an essential role in pedogenesis14,15,16,17,18. Therefore, the difference between large- and micro-topography in the

impact on soil formation process makes it necessary to explore the pedogenesis under the influence of small-scale terrain, especially in hilly mountainous regions with little relief.

Compared to the equivalent background state, the presence of microtopography increases the proportion of rainfall infiltration11. Within the influence of microtopography, the rainfall

distribution pattern and surface operation mode are completely different. In addition, microtopography can control a series of geomorphic processes, such as collapse, transportation, and

accumulation, to alter the spatial redistribution of light, heat, water, nutrients, and soils in a small area, thus affecting vegetation growth3,4,19. The redistribution of water and soil

material caused by microtopography is the main factor in soil spatial variation and an poses an obstacle to the utilisation of soil resources13, especially in hilly mountainous regions.

Several studies have demonstrated the close relationship between small-scale landscape topography and soil physicochemical properties such as soil compactness index (bulk density, clay and

clay/organic matter ratio)7, pH3, weathering degree20,21,22, clay mineral composition23, and microbial community abundance4,24. These factors should be considered in small-scale

environmental analysis13. Specifically, microtopography characteristics are key factors that control soil pH in flysch regions across Switzerland by affecting pedogenesis processes and

vegetation3. Pal et al.25 discovered that presence of microtopography led to the formation of non-alkaline and highly alkaline soils on the upper and lower slopes, respectively, of the

southwestern Indo-Gangetic Plain. Botschek et al.26 noted that the organic matter content was highest in the mineral topsoil on the uphill slope, gradually decreasing towards the foot of the

slope. The current research on the influence of topography on soil formation or soil type primarily focuses on large-scale topography12. The topography of hilly areas (with a relative

height of less than 200 or 100 m) does not usually affect the higher classification types of soil. However, the redistribution of water and heat by microtopography can impact the lower

classification types of soil, such as soil species. Soil species are directly related to soil fertility and land use. There are large hilly areas in the world, and the redistribution of

water and temperature conditions by microtopography will have an important impact on soil formation. However, there are few relevant studies at present, so the study of microtopography on

soil formation has broad significance. The purple mudstone and sandstone in the middle of the Sichuan Basin were eroded by water, leading to the creation of hilly topography. Heat and water

are redistributed in different locations of topography, combined with severe soil erosion, resulting in differences in particle size distribution, nutrient content, water holding capacity,

drought resistance, and fertiliser retention. Therefore, the degree of soil development varies. Finding an effective solution for soil erosion and its related issues in this region is a

significant challenge we are currently facing. Moreover, the mudstone-derived soils that develop from purple mudstone undergo rapid physical weathering but slow chemical weathering,

resulting in the formation of soil particles (i.e., formation of a regolith) in approximately five years27. We hypothesize that in mudstone soil-forming regions with similar parent

materials, comparable climatic conditions, minimal relief of topography, and rapid physical weathering rates, the impact of microtopography might be dominant. Despite numerous researches on

soil water, nutrients, texture and erosion in Sichuan Basin27, there is a lack of research on soil formation characteristics of mudstone under the influence of microtopography. Therefore, we

selected five toposequences of soil derived from mudstone in the hilly regions of Sichuan Basin to explore their physicochemical, morphological, and geochemical properties. The aim of the

present study was to illuminate the weathering development and pedogenic characteristics of mudstone under the influence of microtopographic conditions, ultimately providing a basis for the

management of mudstone soil in mountainous and hilly regions. MATERIALS AND METHODS STUDY AREA The study area, Tongnan District and Dazu District, located in the central Sichuan Basin (Fig. 

1). The area is characterized by predominantly hilly topography and a subtropical monsoon climate. Vegetation types in the study area are consist primarily of subtropical evergreen

broad-leaved forests. The slope of the study area, calculated using a 12.5 m DEM, ranges from 0° to 69°, with a corresponding slope length factor varying from 0 to 55.64. In the period of

2001 to 2020, the multi-year average precipitation and temperature were 1125.4 mm and 18.1 °C, respectively. According to the third national land resource survey, the predominant land use

types in the study area were cultivated land and forest land, both of which account for more than 65% of the total land area (http://ghzrzyj.cq.gov.cn, http://www.cqtn.gov.cn). The soils

were classified as Cambisols in the WRB classification28. SOIL SAMPLING Five natural and typical toposequences were identified, and along each toposequence, five profiles were selected for

sampling based on the microtopography conditions. The sampling points were detailed in Table 1. According to the 1:200,000 regional geological map of China (https://geocloud.cgs.gov.cn) and

the field survey, the parent material of all the sampling points was purple mudstone of the Upper Jurassic Shaximiao Formation in Mesozoic. Additionally, in order to ensure uniformity, other

soil-forming factors such as climate (specifically rainfall and temperature) and organisms (mainly grasses and crops as the predominant surface vegetation, with soil animals detailed in

Table 2) were also investigated for each sampling point, in addition to the terrain (Table 1). Additionally, according to the formula reported by Caniani et al.29, the topographic index

(TPI) of each sampling point was calculated by using a 12.5 m DEM, which reflected the flow accumulation of each sampling point (Table 1). A higher TPI indicates a larger accumulation of

discharge, relatively low-lying terrain, and higher soil water content. Five soil samples with five repetitions each were collected at the summit, shoulder, backslope, footslope, and

toeslope positions of the hillslope (Fig. 2). Soil samples were collected from the excavated soil profiles, sampling from the toeslope to the summit based on soil genesis characteristics,

which were divided into horizons A, B, and C. The GPS locator was used to record the coordinates, altitude, and slope of the sampling points. Additionally, the morphological characteristics

of the soil profiles were recorded according to the _Field Book for Describing and Sampling Soils (version 3.0)_30 (Table 2). Soil samples were taken to the laboratory for chemical, physical

and mineralogical analyses, totalling 125 samples (approximately 500 g each). All the samples were air-dried. and then sieved through a 2 mm sieve after the removal of visible plant debris

for laboratory analysis. EXPERIMENTAL METHOD AND DATA ANALYSIS PHYSICAL AND MINERALOGICAL METHODS The soil bulk density was determined using the soil core (volume = 100 cm3) method. Prior to

conducting the soil particle size analysis (PSA), hydrogen peroxide was used to remove organic matter. The removal of iron oxide was achieved using a sodium bicarbonate-buffered, sodium

dithionite-citrate system, while sodium acetate was utilized to remove carbonate. Sodium hexametaphosphate was used to disperse soil particles and PSA was determined by pipette method32.

Soil porosity (_φ_) can be calculated by the following formula32, $$\varphi = \left( {1 - \frac{{\rho_{b} }}{{\rho_{p} }}} \right) \times 100$$ (1) where _ρ__b_ and _ρ__p_ represent bulk

density (g cm−3) and particle density, respectively. Particle density was determined by pycnometer method. X-ray diffraction (XRD: D8 Advance X-ray diffractometer, Bruker, Germany) was

utilized to analyze the mineral composition of soil samples. The soil samples were crushed to particle size < 1 mm, soaked in distilled water, and dispersed by ultrasonic wave. Carbonate

and organic matter were removed from the samples, and the clay particles were absorbed by suspension centrifugation to settle. After centrifugation, the samples were dried at a temperature

below 60 °C. The dried samples were ground with an agate mortar until the hands had no granular feeling, and then wrapped in paper for XRD determination. The X-ray diffractometer parameters

were set as follows: the radiation source was CuKα, the scanning speed was set to 2° min−1, the sampling step width was 0.02°, and the scanning range was 5°–45°. The diffraction data was

interpreted based on the X-ray diffraction pattern of soil samples, and then compared with known standard minerals data to identify the minerals types present in the soil. The percentage of

minerals in the soil was calculated by using the integral intensity of diffraction peaks on the diffraction pattern and the reference intensity of common minerals33. CHEMICAL METHODS A glass

electrode was used to measure the soil pH in a 1:2.5 soil/water suspension ratio. Soil organic carbon (SOC) content was determined using the dichromate-wet combustion method, and the C/N

ratio was calculated as the ratio of SOC to total nitrogen (TN) content (determined by the Kjeldahl method). Cation exchange capacity (CEC) was determined using the Na saturation method.

Each sample (0.5 g) was ground to 100 mesh (0.15 mm) in an agate mortar and formed into a tablet to measure the geochemical elements of the test soil using X-ray fluorescence

spectrometry32,34. These geochemical elements include macroelements, trace elements, rare-earth elements, and radioactive elements. The content and composition characteristics of

macroelements are widely used as indicators. Therefore, the geochemical elements in this study refer to the 10 macroelements35. The chemical index of alteration (CIA) is the measure of the

degree of the feldspar-to-clay conversion, which is proportional to the clay mineral/feldspar ratio. During chemical weathering, alkali metals are leached out from feldspar in the form of

ions, leading to the formation of clay minerals and simultaneous fluctuation in the molar content of Al2O3. Thus, CIA is defined as follows36, $${\text{CIA}} = \left( {\frac{{{\text{Al}}_{2}

{\text{O}}_{3} }}{{{\text{Al}}_{2} {\text{O}}_{3} + {\text{CaO}}^{*} + {\text{Na}}_{2} {\text{O}} + {\text{K}}_{2} {\text{O}}}}} \right) \times 100$$ (2) where all variables represent the

molar faction of macroelement oxides and CaO* is the molar faction of CaO associated with silicate minerals calculated using the McLennan method37. Generally, CIA values are below 50 for

unweathering with feldspar, 50–65 for weak weathering with plagioclase, 65–85 for moderate weathering with illite and montmorillonite, and near 100 for strong weathering with kaolinite and

chlorite. Additionally, CIA indirectly indicates the change in climate, with higher CIA values reflecting warmer and wetter climates. The chemical index of weathering (CIW) is conceptually

and computationally similar to CIA, except for the lack of K2O. Many scholars have found that the content of K in a sedimentary area is higher than that in provenance rock area, probably due

to K metasomatism or the addition of eolian dust undergoing diagenetic processes. To eliminate the interference of diagenetic K, the concept of the CIW was proposed by Holail and Moghazi38,

$${\text{CIW}} = \left( {\frac{{{\text{Al}}_{2} {\text{O}}_{3} }}{{{\text{Al}}_{2} {\text{O}}_{3} + {\text{CaO}}^{*} + {\text{Na}}_{2} {\text{O}}}}} \right) \times 100$$ (3) where the

oxides are given in molar faction and CaO* is calculated by the same method of the CIA. Chemical weathering increase is indicated by high CIW values. The Na/K molar ratio indicates the

extent of chemical weathering of plagioclase. Plagioclase is rich in Na, especially compared to potassium feldspar, which is rich in K. Plagioclase undergoes a higher rate weathering

compared to potassium feldspar10,35, resulting in an inverse relationship between chemical weathering intensity and the Na/K molar ratio39. The migration coefficient of element X (_MC__X_)

represents the migration and enrichment characteristics of soil profile relative to bedrock during pedogenesis40,41,42. Titanium (Ti) is commonly used as a stationary component to determine

the movement of other elements40, enabling for the inference of soil development degree and rate. The _MC__X_ can be calculated by the following formula, $$MC_{X} = \left( {\frac{{X_{soil}

}}{{X_{rock} }} \times \frac{{Ti_{rock} }}{{Ti_{soil} }} - 1} \right) \times 100$$ (4) where soil and rock subscripts in the formula represent the concentrations of elements X and Ti in soil

and bedrock, respectively. A _MC__X_ > 0 indicates that element X is enriched in the soil horizon relative to the parent rock and Ti, while a _MC__X_ < 0 indicates X is leaching or

migration in the soil horizon. STATISTICAL ANALYSIS METHODS One-way ANOVA and a mean comparison according to the LSD (_p_ < 0.05) were used to evaluate the differences in physicochemical

properties among landscape slope positions and soil profile horizons. Statistical analyses were conducted using SPSS 19.0. The distribution map of the sampling sites was drafted using ArcGIS

10.8, and the other diagrams were created using Excel 2016 and Origin 9.3. RESULTS SOIL MORPHOLOGY As shown in Table 2, the profiles with the pattern of A–C horizons were mainly

concentrated at the summit and shoulder of the hillslope, the profile at the backslope and footslope was the A–B–C horizon, and the toeslope was the A–B horizon within the excavation depth.

From the summit to the toeslope, the soil thickness increased significantly with the change in the soil profile configuration from 16.50 to 93.60 cm (_p_ = 0.000). In the study area, there

were three types of soil colour hues, including 10R, 2.5YR, and 5YR. The soil texture of horizon C was loam, whereas that of horizon B was mostly loam and clay loam. The soil texture of

horizon A was loam to clay loam, from the summit to the toeslope (Table 3). The main soil structure of each horizon was blocky or/and granular, and the organic matter accumulation in the

surface horizon, combined with mechanical ploughing, loosened the soil. The presence of a granular structure in the soil, typically characterized by loose porosity and good permeability, was

generally beneficial for improving soil structure. The cohesiveness of the soil in horizon A was non-sticky, slightly sticky, and sticky from the summit to the toeslope. The cohesiveness of

horizon B was mostly sticky, while that of horizon C was mostly non-sticky. Due to human cultivation or mechanical tillage, there was a small amount of intrusive material in the soil,

mainly consisting of brick, tile debris, and a small amount of coal cinder. The parent rock of mudstone soil was sedimentary rock, most lacustrine facies sedimentary rock deposited during

the Jurassic and Cretaceous periods, resulting in the presence of a small number of shells in the soil. SOIL PHYSICAL AND CHEMICAL PROPERTIES The bulk density and porosity of the soil

profiles at different slope positions were showed in Table 3. The bulk density of horizons A and B of the soil profiles gradually increased from the summit to the toeslope. Additionally, the

bulk density of horizon A was found to be lower than that of horizon B at all slope positions. The porosity in horizons A and B of the soil profiles also decreased gradually from the summit

to the toeslope. The porosity of horizon A was higher than that of horizon B. This was primarily due to clays and oxides (such as iron and aluminum oxides) were leached downward and

accumulated in the horizon B under the action of percolating water, leading to a decrease in porosity. Additionally, the topsoil was typically rich in organic matter and had higher porosity

compared to the subsoil. As indicated in Table 3, the content of sand and silt fractions in horizons A and B decreased gradually from the summit to the toeslope. Conversely, the clays

fraction content in horizons A and B increased gradually from the summit to the toeslope. As shown in Fig. 3, the pH of the different horizons showed an order of C > B > A, and with a

decreasing trend from the summit to the toeslope. The SOC content in horizon C was low, with no significant difference among the different slope positions (_p_ = 0.978). The SOC content in

horizons A and B gradually increased with decreasing slope elevation, and the difference in SOC above and below the backslope was significant (_p_ = 0.000). The accumulation of SOC in

horizon A at the footslope and toeslope was mainly due to soil erosion, cultivation and fertilisation, while the accumulation of SOC in horizon B was mainly caused by detachment,

transportation, accumulation, and burial of deep soil in the higher topography. The hilly terrain was conducive to the accumulation of SOC content at the footslope and toeslope. Part of the

P in the soil came from the parent rock, whereas the other part came from the application of chemical fertilisers and plant decomposition. Although phosphorus was generally considered to be

relatively immobile in the soil, it could also be redistributed through the erosion of phosphorus-containing soil particles, dissolution into runoff and migration along the slope, and

leaching into the ground. Therefore, the variation in phosphorus content was observed across different slope positions and profile levels during the soil formation process (Fig. 3). Total

phosphorus (TP) in the soil at the summit of the slope was significantly lower than that in the toeslope (_p_ = 0.043). The TP in the soil above the backslope was in the order of horizon B 

> C > A, whereas that in the footslope and toeslope was A > B > C. The TN content from the summit to the toeslope increased with decreasing slope elevation, and there was a

significant difference above and below the backslope (_p_ = 0.000), indicating that there was TN accumulation at the foot and toeslope. In general, the TN above the backslope was in the

order of horizon A > B > C of the soil profile, whereas that of the footslope and toeslope was horizon B > A > C (Fig. 4). The total potassium (TK) content from the summit to the

toeslope gradually increased with decreasing slope elevation. There was a significant difference between the summit, shoulder of the slope and footslope, and toeslope, indicating that K in

the soil accumulated at a lower topographic position (_p_ = 0.000). According to the different horizons, the TK in the soil above the backslope was in the order of horizon C > B > A,

whereas that at the footslope was horizon A > C > B (Fig. 3). There were differences in the CEC content among the different soil horizons. The average CEC contents in horizons A, B,

and C were 27.37, 29.67, and 28.36 cmol(+) kg−1, respectively. These results indicated that cations migrated and leached in horizon A, accumulating and becoming enriched in horizon B. The

CEC above the backslope followed the order of horizon C > B > A, while below the backslope it was B > A > C. As shown in Table 4, a noticeable negative correlation was found

between sand content and SOC, TN, TK, CEC, and bulk density, and a significant positive correlation was observed between sand content and pH and porosity (_p_ < 0.05). There was a

significant negative correlation between silt content and the levels of SOC, TN, TP, TK, and CEC, as well as a significant positive correlation between silt content and pH (_p_ < 0.05).

Additionally, there was a negative correlation between clay content and pH and porosity, but a significant positive correlation between clay content and SOC, TN, TK, CEC, and bulk density

(_p_ < 0.05). GEOCHEMICAL COMPOSITION AND CHEMICAL WEATHERING INDICES In general, the footslope and toeslope of the hillslope showed accumulation of Al, Fe, Mg, and K, and leaching loss

of Ca and Na compared with the summit and shoulder of the hillslope. There was a leaching loss of K in horizon A at the summit of the hillslope, while the variation in elements in each

horizon at the shoulder of the hillslope was not obvious (Table 5). As demonstrated in Table 5, Al, Fe, and Mg accumulated in horizon B, whereas the percentages of Ca and Na in horizon B

were lower compared to horizons A and C. Additionally, Si exhibited a trend of A > B > C across various soil profile horizons. Generally, weathering tended to be most intense nearest

the soil surface. Part of the weathering products formed in horizon A were leached downward under the action of percolating water, coupled with the weathering materials of horizon B itself,

which led to the accumulation of Al, Fe and Mg in horizon B. Simultaneously, minerals with low weathering stability were gradually destroyed and reduced, while quartz with high weathering

stability was enriched. This resulted in a sequential decrease in the percentage of Si from topsoil to subsoil. The leaching of Na and Ca was significant in horizons A and B (_p_ < 0.05),

whereas the leaching of Ca and Na was obvious in horizon B relative to horizon A in the hillslope. During the development of silicate soils, Na and Ca were leached first, followed by K, and

Al and Fe were relatively enriched. The soil in this study was in the stage of leaching of Ca and Na, the leaching of soil geochemical elements was not strong, and the degree of soil

development was weak. The effect of microtopography on soil chemical weathering was greater than that on the profile. The chemical index of alteration (CIA) exhibited an increasing trend,

whereas Na/K demonstrated a converse trend from summit to toeslope (Fig. 4a). The CIA values of summit, shoulder, backslope, footslope, and toeslope were 71.78, 73.17, 72.51, 74.55, and

74.55, respectively (Fig. 4b). The CIA values of horizons A, B, and C were 72.92, 74.37, and 72.61, respectively (Fig. 4c). There were significant differences in CIA values between horizons

A and B, B and C (_p_ = 0.000). The variation trend of chemical index of weathering (CIW) was basically the same as that of CIA. Furthermore, both CIA and CIW have similar indicators for

reflecting the degree of soil weathering. The variance _F_ value of the soil chemical weathering index under different factors demonstrated that the CIA, CIW, and Na/K of soil varied

significantly between different horizons at various slope positions. Additionally, there was a significant interaction between slope position and horizon (Table 6). Simultaneously, the CIA,

CIW, and Na/K values indicated that the soil in the study area had moderate chemical weathering, and the chemical weathering of the soil parent horizon remained at the same level from the

summit to the toeslope of the hillslope. The CIA, CIW, and Na/K values of horizons A and B showed a trend of initially increasing and then decreasing with decreasing slope elevation. Horizon

B at the footslope exhibited the highest degree of development, which indicated that the eroded and weathered material stripped and transported from higher landscape positions was deposited

into horizon B at the footslope duo to topographical influences. As shown in Fig. 5, the mobility of the elements varied at different landscape positions. The migration directions of Ca and

Na at the summit and backslope were completely opposite to that at the footslope. The average migration coefficients of Ca at the summit, backslope, and footslope were 1.43%, − 4.93%, and −

 33.43%, respectively. The average migration coefficients of Na were 16.15%, 1.73%, and − 18.43%, respectively, and the migration direction changed from enrichment to leaching. Al, Fe, and

Mg were first leached and then enriched from the summit to the footslope, which may be due to the higher sand content in the soil and relatively large intergranular pores, resulting in the

loss of elements under the action of rainfall and underground runoff. However, in areas with relatively low terrain, like the footslope, the abundant water conditions provided the ideal

environment for soil chemical weathering. This led to the leaching of Ca and Na, while Al and Fe became enriched. MINERALOGY CHARACTERISTICS The mineral composition of the soils was analysed

using X-ray diffraction (Fig. 6). There was an evident mineralogical similarity between the soils at different slope positions and horizons. The mudstone soils in this study were primarily

composed of illite, kaolinite, and an illite/smectite mixed horizon. The mineral composition of the soils closely resembled that of their parent rock. These results indicated that the clay

minerals in the soils originated mostly from the parent material and that they were only slightly influenced by soil-forming processes. DISCUSSION EFFECT OF MICROTOPOGRAPHY ON THE PHYSICAL

AND CHEMICAL WEATHERING OF THE SOIL AT DIFFERENT SLOPE POSITIONS The spatial heterogeneity in particle size distribution, pH, SOC, elements, and CEC across landscape positions were

influenced by microtopography43,44. A study conducted on the Moody and Nora soil system toposequences formed in calcareous loess in eastern Nebraske showed that sand, silt, and pH exhibited

an overall increasing trend from the top to the bottom of the slope. Inversely, clay particles, organic matter (excluding toeslope), and CEC showed a decreasing trend43. This is contrary to

our findings. The differences in particle size distribution among landscape positions may be attributed to soil erosion and the downward migration of clay particles under the action of

percolating water10. In the present study, the texture of horizon A primarily ranged from loam to clay loam. On one hand, due to the influence of surface runoff, partial clay particles

migrated along the slope and accumulate at the bottom45,46,47. On the other hand, under the action of percolating water, the smallest clay particles were leaching downward into the

underlying horizons, resulting in an increase in the percentage of clay in horizon B (Table 3). Zhong et al.48 also showed that the sand content and mineral sand of 0.25–2 mm in the soil,

developed by shale and mudstone, decreased from the top to the foot of the slope. In contrast, the clay content and aggregate content of 0.25–2 mm increased. The opposite trend in pH

observed may be attributed to the topsoil analyzed by Brubaker et al.43 being rich in Ca, and the Mg content increased continuously from the summit to toeslope. Although some leaching occurs

during the downslope migration, a considerable portion still migrates to the bottom of the slope, resulting in enrichment. The decrease in organic matter from summit to footslope may also

contribute to the increase in pH. In this study, the continuous enrichment of Al, leaching of Ca and accumulation of organic matter from the summit to toeslope resulted in the decrease of

soil pH. This was further illustrated by the significant negative correlation between pH and aluminum oxide and SOC in Table 4. The increase in SOC from the summit to the toeslope may be

related to soil erosion. A study of toposequences in olive grove in the Mediterranean also indicated that erosion caused the transfer of organic matter from the summit to the toeslope44.

Ouyang et al.17 conducted a study on the CEC value of soils developed in granite, slate, limestone, sandstone and quaternary red clay in mid-subtropical Hunan Province, China. This study

demonstrated that the CEC value was higher on the footslope compared to the backslope. The findings of the present study corroborate these results, showing that the CEC values on the

footslope and toeslope were higher compared to other landscape positions. This higher CEC value was attributed to the accumulation of SOC and clay particles, as indicated by a significant

positive correlation in Table 4. The degree of soil chemical weathering varied with changes in the slope position and soil depth. Topographic changes caused differences in chemical

weathering of the soil profile, mainly because the soil at the top and shoulder of the slope was mostly developed under natural conditions and rarely affected by human beings. In these

areas, soil weathering mainly depended on the changes in natural climate conditions and the effect of soil organisms. Conversely, at the footslope and other relatively low topographic

locations, soil moisture is retained, providing ideal moisture conditions for chemical weathering to occur. Meanwhile, the soil on the footslope and toeslope was affected by cultivation

practices. Irrigation alters the soil moisture status, tillage changes soil aeration conditions49, and fertilisation increases soil nutrient elements. These factors contribute to soil

mineral weathering and nutrient leaching, while also intensifying soil erosion50,51,52. Therefore, soil erosion caused by tillage promotes chemical weathering in the soil. THE REDISTRIBUTION

OF FLOW AND MATERIALS BY MICROTOPOGRAPHY RESULTED IN THE DIFFERENCE OF PEDOGENIC CHARACTERISTICS AT DIFFERENT SLOPE POSITIONS Water runs through the entire process of soil occurrence and

development. It plays a crucial role in soil formation by serving as the primary medium for transporting solids and ions within the soil53. Microtopography dominates surface hydrological

processes and affects water redistribution54,55, leading to variations in the physicochemical properties of soil at different slope positions15. In low-lying areas, the regolith is typically

more extensively weathered, and the soil profile is developed with greater intensity due to the accumulation of flowing water. This water saturation also restricts drainage and ventilation,

limiting the weathering of certain minerals and the decomposition of organic matter10. Therefore, even within a microdomain of tens of meters, the soil of the same genus also forms

different textures owing to the various properties. In this study, the physicochemical properties of the soil varied with the change in the slope position, particularly between the soil

above and below the backslope, with differences also seen among different horizons. The mudstone parent rock, exposed at the summit of the hilly mountainous region caused by erosion, is rich

in clay minerals and has a strong water absorption capacity. Therefore, it is easily weathered physically under the influence of moist heat expansion. Consequently, stony subsoil is

frequently formed at or near the summit of the slope48. Obi et al.46 showed that sand content is affected by rainfall and infiltration. Excessive rainfall, when surpassing infiltration,

leads to the redistribution of sand within the slope and soil horizon. This particular occurrence is commonly witnessed during thunderstorm weather conditions, subsequently compromising the

stability of the soil surface on the slope56,57. Additionally, the study findings indicate that the level of chemical weathering in horizon A at the footslope and toeslope was comparatively

lower than that of horizon B. This disparity can be attributed to the redistribution of soil materials brought about by microtopography3. This finding contradicts the results of other

toposequences, which indicated that horizon A (or topsoil) undergoes greater chemical weathering than horizon B (or subsoil)21,58. This could be due to severe soil and water loss in hilly

mountainous regions, where materials transported by upper erosion are deposited at the footslope and toeslope. Long-term contact between water and sediment leads to further chemical action,

resulting in soil with a high organic matter content and fine texture. This soil is then buried by a new round of denudation accumulation and self-weathered soil, eventually becoming a

B-horizon with a higher degree of development than the topsoil. CONCLUSION In this study, we investigated the influence of microtopography on the morphological characteristics,

physiochemistry, and geochemical attributes of the profiles. The results indicated that the morphological characteristics of the mudstone soil profile were mainly inherited and affected by

the parent material. From the summit to the toeslope, the profile configuration of the mudstone soil changed from A–C to A–B–C, and the thickness of the soil increased significantly. The

bulk density, clay fraction, soil organic matter, TN, TP, TK, and CEC increased from the summit to the toeslope of the hillslope, whereas the pH, porosity, sand, and silt fraction decreased.

The total contents of Ca and Na at the summit, backslope, and footslope decreased due to the continuous leaching along the downslope direction, while the total contents of Al, Fe and Mg

showed an opposite trend. The degree of soil development was relatively weak at the summit and shoulder of the hillslope, but higher at the footslope and toeslope. Microtopography may

influence physicochemical properties, chemical weathering, and redistribution of water and materials, leading to variations in pedogenic characteristics at different slope positions. DATA

AVAILABILITY All raw data can be obtained from the corresponding authors on request. REFERENCES * Leguédois, S. _et al._ Modelling pedogenesis of Technosols. _Geoderma_ 262, 199–212.

https://doi.org/10.1016/j.geoderma.2015.08.008 (2016). Article  ADS  Google Scholar  * Deressa, A., Yli-Halla, M., Mohamed, M. & Wogi, L. Soil classification of humid Western Ethiopia: A

transect study along a toposequence in Didessa watershed. _CATENA_ 163, 184–195. https://doi.org/10.1016/j.catena.2017.12.020 (2018). Article  CAS  Google Scholar  * Baltensweiler, A.,

Heuvelink, G. B. M., Hanewinkel, M. & Walthert, L. Microtopography shapes soil pH in flysch regions across Switzerland. _Geoderma_ 380, 114663.

https://doi.org/10.1016/j.geoderma.2020.114663 (2020). Article  ADS  CAS  Google Scholar  * Lv, W. _et al._ Microtopography mediates the community assembly of soil prokaryotes on the

local-site scale. _CATENA_ 222, 106815. https://doi.org/10.1016/j.catena.2022.106815 (2023). Article  CAS  Google Scholar  * Darmody, R. G., Thorn, C. E. & Allen, C. E. Chemical

weathering and boulder mantles, Kärkevagge, Swedish Lapland. _Geomorphology_ 67, 159–170. https://doi.org/10.1016/j.geomorph.2004.07.011 (2005). Article  ADS  Google Scholar  * Luo, J.,

Zheng, Z., Li, T. & He, S. Spatial variation of microtopography and its effect on temporal evolution of soil erosion during different erosive stages. _CATENA_ 190, 104515.

https://doi.org/10.1016/j.catena.2020.104515 (2020). Article  Google Scholar  * Parent, A. C. _et al._ Soil properties and landscape factors affecting maize yield under wet spring conditions

in eastern Canada. _Biosyst. Eng._ 99, 134–144. https://doi.org/10.1016/j.biosystemseng.2007.10.006 (2008). Article  Google Scholar  * Salako, F. K. _et al._ Soil strength and maize yield

after topsoil removal and application of nutrient amendments on a gravelly Alfisol toposequence. _Soil Tillage Res._ 94, 21–35. https://doi.org/10.1016/j.still.2006.06.005 (2007). Article 

Google Scholar  * Veneman, P. L. M., Jacke, P. V. & Bodine, S. M. Soil formation as affected by pit and mound microrelief in Massachusetts, USA. _Geoderma_ 33, 89–99.

https://doi.org/10.1016/0016-7061(84)90022-3 (1984). Article  ADS  Google Scholar  * Weil, R. & Brady, N. _The nature and properties of soils_ (Pearson Press, 2017). Google Scholar  *

Thompson, S. E., Katul, G. G. & Porporato, A. Role of microtopography in rainfall-runoff partitioning: An analysis using idealized geometry. _Water Resour. Res._

https://doi.org/10.1029/2009WR008835 (2010). Article  Google Scholar  * Felix-Henningsen, P., Liang-wu, L. & Zakosek, H. Distribution and genesis of red and yellow soils in the central

subtropics of southeast China. _CATENA_ 16, 73–89. https://doi.org/10.1016/0341-8162(89)90005-2 (1989). Article  CAS  Google Scholar  * Kokulan, V., Akinremi, O., Moulin, A. P. &

Kumaragamage, D. Importance of terrain attributes in relation to the spatial distribution of soil properties at the micro scale: A case study. _Can. J. Soil. Sci._ 98, 292–305.

https://doi.org/10.1139/cjss-2017-0128 (2018). Article  CAS  Google Scholar  * Silva, M. B. _et al._ Soils in the karst landscape of Bodoquena plateau in cerrado region of Brazil. _CATENA_

154, 107–117. https://doi.org/10.1016/j.catena.2017.02.022 (2017). Article  CAS  Google Scholar  * Maranhão, D. D. C. _et al._ Pedogenesis in a karst environment in the Cerrado biome,

northern Brazil. _Geoderma_ 365, 114169. https://doi.org/10.1016/j.geoderma.2019.114169 (2020). Article  ADS  CAS  Google Scholar  * Fonseca, J. D. S. _et al._ Soil–landscape relationship in

a sandstone-gneiss topolithosequence in the State of Amazonas. _Braz. Environ. Earth Sci._ 80, 714. https://doi.org/10.1007/s12665-021-10026-9 (2021). Article  ADS  Google Scholar  *

Ouyang, N. _et al._ Cation exchange properties of subsurface soil in mid-subtropical China: Variations, correlation with soil-forming factors, and prediction. _Agronomy_ 13, 741.

https://doi.org/10.3390/agronomy13030741 (2023). Article  CAS  Google Scholar  * McGraw, A., Ramsey, R. C., Obura, P., Matocha, C. & Shepard, C. Topographic gradients of soil physical,

chemical, and mineralogical properties in central Kentucky sinkholes. _Soil Sci. Soc. Am. J._ 87, 82–103. https://doi.org/10.1002/saj2.20478 (2023). Article  ADS  CAS  Google Scholar  *

Nagamatsu, D., Hirabuki, Y. & Mochida, Y. Influence of micro-landforms on forest structure, tree death and recruitment in a Japanese temperate mixed forest: Influence of landforms on a

Japanese forest. _Ecol. Res._ 18, 533–547. https://doi.org/10.1046/j.1440-1703.2003.00576.x (2003). Article  Google Scholar  * Phillips, J. D., Turkington, A. V. & Marion, D. A.

Weathering and vegetation effects in early stages of soil formation. _CATENA_ 72, 21–28. https://doi.org/10.1016/j.catena.2007.03.020 (2008). Article  Google Scholar  * Oliveira, D. P. _et

al._ Weathering and clay formation in semi-arid calcareous soils from Northeastern Brazil. _CATENA_ 162, 325–332. https://doi.org/10.1016/j.catena.2017.10.030 (2018). Article  CAS  Google

Scholar  * Pinheiro Junior, C. R. _et al._ Pedogenesis on Jurassic formations in the Araripe Basin, northeastern Brazil: Weathering and parent material. _CATENA_ 223, 106952.

https://doi.org/10.1016/j.catena.2023.106952 (2023). Article  CAS  Google Scholar  * Ouyang, N. _et al._ Clay mineral composition of upland soils and its implication for pedogenesis and soil

taxonomy in subtropical China. _Sci. Rep._ 11, 9707. https://doi.org/10.1038/s41598-021-89049-y (2021). Article  ADS  CAS  PubMed  PubMed Central  Google Scholar  * Wang, Y., Li, S., Lang,

X., Huang, X. & Su, J. Effects of microtopography on soil fungal community diversity, composition, and assembly in a subtropical monsoon evergreen broadleaf forest of Southwest China.

_CATENA_ 211, 106025. https://doi.org/10.1016/j.catena.2022.106025 (2022). Article  Google Scholar  * Pal, D. K., Srivastava, P., Durge, S. L. & Bhattacharyya, T. Role of microtopography

in the formation of sodic soils in the semi-arid part of the Indo-Gangetic Plains, India. _CATENA_ 51, 3–31. https://doi.org/10.1016/S0341-8162(02)00092-9 (2003). Article  CAS  Google

Scholar  * Botschek, J., Ferraz, J., Jahnel, M. & Skowronek, A. Soil chemical properties of a toposequence under primary rain forest in the Itacoatiara vicinity (Amazonas, Brazil).

_Geoderma_ 72, 119–132. https://doi.org/10.1016/0016-7061(96)00026-2 (1996). Article  ADS  CAS  Google Scholar  * Zhong, S. _et al._ Relationships between the lithology of purple rocks and

the pedogenesis of purple soils in the Sichuan Basin, China. _Sci. Rep._ 9, 13272. https://doi.org/10.1038/s41598-019-49687-9 (2019). Article  ADS  CAS  PubMed  PubMed Central  Google

Scholar  * IUSS Working Group WRB. _World Reference Base for Soil Resources, International soil classification system for naming soils and creating legends for soil maps_. (2022). * Caniani,

D., Pascale, S., Sdao, F. & Sole, A. Neural networks and landslide susceptibility: A case study of the urban area of Potenza. _Nat. Hazards_ 45, 55–72.

https://doi.org/10.1007/s11069-007-9169-3 (2008). Article  Google Scholar  * Schoeneberger, P. J., Wysocki, D. A., Benham, E. C., & Soil Survey Staff. _Field Book for Describing and

Sampling Soils_. (Natural Resources Conservation Service, National Soil Survey Center, 2012). * He, C., Wang, M., Liu, K. & Jiang, Z. GPRChinaTemp1km: 1 km monthly mean air temperature

for China from January 1951 to December 2020. https://doi.org/10.5281/zenodo.5111989 (2021). * Camobell, G. S. _et al. Methods of soil analysis, Part 4: Physical methods, number 5 in the

soil science society of America book series._ (Soil Science Society of America, 2002). * National Energy Administration. Analysis method for clay minerals and ordinary non-clay minerals in

sedimentary rocks by the X-ray diffraction. (2018). * Sparks, D. L. _et al. Methods of soil analysis, part 3: Chemical methods, number 5 in the soil science society of America book series_.

(Soil Science Society of America and American Society of Agronomy, 1996). * Tang, J., Han, Z., Zhong, S., Ci, E. & Wei, C. Changes in the profile characteristics of cultivated soils

obtained from reconstructed farming plots undergoing agricultural intensification in a hilly mountainous region in southwest China with regard to anthropogenic pedogenesis. _CATENA_ 180,

132–145. https://doi.org/10.1016/j.catena.2019.04.020 (2019). Article  CAS  Google Scholar  * Nesbitt, H. W. & Young, G. M. Early Proterozoic climates and plate motions inferred from

major element chemistry of lutites. _Nature_ 299, 715–717. https://doi.org/10.1038/299715a0 (1982). Article  ADS  CAS  Google Scholar  * McLennan, S. M. Weathering and global denudation. _J.

Geol._ 101, 295–303. https://doi.org/10.1086/648222 (1993). Article  ADS  Google Scholar  * Holail, H. M. & Moghazi, A.-K.M. Provenance, tectonic setting and geochemistry of greywackes

and siltstones of the Late Precambrian Hammamat Group, Egypt. _Sediment. Geol._ 116, 227–250. https://doi.org/10.1016/S0037-0738(97)00104-8 (1998). Article  ADS  CAS  Google Scholar  *

Pettijohn, F. J., Potter, P. E. & Siever, R. _Sand and Sandstone_ (Springer, 1987). Book  Google Scholar  * Nesbitt, H. W. Mobility and fractionation of rare earth elements during

weathering of a granodiorite. _Nature_ 279, 206–210. https://doi.org/10.1038/279206a0 (1979). Article  ADS  CAS  Google Scholar  * Kurtz, A. C., Derry, L. A., Chadwick, O. A. & Alfano,

M. J. Refractory element mobility in volcanic soils. _Geology_ 28, 683. https://doi.org/10.1130/0091-7613(2000)28%3c683:REMIVS%3e2.0.CO;2 (2000). Article  ADS  CAS  Google Scholar  * Xia, J.

_et al._ Migration and transformation of soil mercury in a karst region of southwest China: Implications for groundwater contamination. _Water Res._ 226, 119271.

https://doi.org/10.1016/j.watres.2022.119271 (2022). Article  CAS  PubMed  Google Scholar  * Brubaker, S. C., Jones, A. J., Lewis, D. T. & Frank, K. Soil properties associated with

landscape position. _Soil Sci. Soc. Am. J._ 57, 235–239. https://doi.org/10.2136/sssaj1993.03615995005700010041x (1993). Article  ADS  Google Scholar  * Lozano-García, B. &

Parras-Alcántara, L. Variation in soil organic carbon and nitrogen stocks along a toposequence in a traditional Mediterranean olive grove. _Land Degrad. Dev._ 25, 297–304.

https://doi.org/10.1002/ldr.2284 (2014). Article  Google Scholar  * Tsatskin, A., Sandler, A. & Porat, N. Toposequence of sandy soils in the northern coastal plain of Israel: Polygenesis

and complexity of pedogeomorphic development. _Geoderma_ 197–198, 87–97. https://doi.org/10.1016/j.geoderma.2013.01.001 (2013). Article  ADS  CAS  Google Scholar  * Obi, J. C., Ogban, P.

I., Ituen, U. J. & Udoh, B. T. Development of pedotransfer functions for coastal plain soils using terrain attributes. _CATENA_ 123, 252–262. https://doi.org/10.1016/j.catena.2014.08.015

(2014). Article  Google Scholar  * Corrêa De Medeiros, P. S., Do Nascimento, P. C., Inda, A. V. & Da Silva, L. F. Genesis and classification of soils from granitic hills in southern

Brazil. _J. South Am. Earth Sci._ 98, 102494. https://doi.org/10.1016/j.jsames.2019.102494 (2020). Article  CAS  Google Scholar  * Zhong, S., Wei, C., Ni, J., Xie, D. & Ni, C.

Characterization of clay rock-derived soils containing multi-mineral sand particles in upland areas of Sichuan Basin, China. _CATENA_ 194, 104737.

https://doi.org/10.1016/j.catena.2020.104737 (2020). Article  Google Scholar  * Wei, C., Ni, J., Gao, M., Xie, D. & Hasegawa, S. Anthropic pedogenesis of purple rock fragments in Sichuan

Basin, China. _CATENA_ 68, 51–58. https://doi.org/10.1016/j.catena.2006.04.022 (2006). Article  Google Scholar  * He, X., Xu, Y. & Zhang, X. Traditional farming system for soil

conservation on slope farmland in southwestern China. _Soil Tillage Res._ 94, 193–200. https://doi.org/10.1016/j.still.2006.07.017 (2007). Article  Google Scholar  * Ni, S. J. & Zhang,

J. H. Variation of chemical properties as affected by soil erosion on hillslopes and terraces. _Eur. J. Soil Sci._ 58, 1285–1292. https://doi.org/10.1111/j.1365-2389.2007.00921.x (2007).

Article  CAS  Google Scholar  * Zheng, J.-J. _et al._ Assessing soil erosion rates on manually-tilled hillslopes in the Sichuan hilly basin using 137Cs and 210Pbex measurements. _Pedosphere_

17, 273–283. https://doi.org/10.1016/S1002-0160(07)60034-4 (2007). Article  CAS  Google Scholar  * Schaetzl, R. & Anderson, S. _Soils: Genesis and Geomorphology_ (Cambridge University

Press, 2005). Book  Google Scholar  * Peñuela, A., Javaux, M. & Bielders, C. L. How do slope and surface roughness affect plot-scale overland flow connectivity?. _J. Hydrol._ 528,

192–205. https://doi.org/10.1016/j.jhydrol.2015.06.031 (2015). Article  ADS  Google Scholar  * Muscarella, R., Kolyaie, S., Morton, D. C., Zimmerman, J. K. & Uriarte, M. Effects of

topography on tropical forest structure depend on climate context. _J. Ecol._ 108, 145–159. https://doi.org/10.1111/1365-2745.13261 (2020). Article  Google Scholar  * Oguike, P. C. &

Mbagwu, J. S. C. Variations in some physical properties and organic matter content of soils of coastal plain sand under different land use types. 7 (2009). * Eneje, R. C. & Adanma, N.

Percent clay, aggregate size distribution and stability with depth along a toposequence formed on coastal plain sands. _Online J. Earth Sci._ 108–112 (2012). * Vanacker, V. _et al._ Land use

impacts on soil erosion and rejuvenation in Southern Brazil. _CATENA_ 178, 256–266. https://doi.org/10.1016/j.catena.2019.03.024 (2019). Article  CAS  Google Scholar  Download references

ACKNOWLEDGEMENTS Acknowledgement for the data support from “National Earth System Science Data Center, National Science & Technology Infrastructure of China. (http://www.geodata.cn)”.

FUNDING This study was supported by the Fundamental Research Funds for the National Natural Science Foundation of China (42077007), and the Startup Project of Doctor Scientific Research at

Southwest University (No. SWU120065). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * College of Resources and Environment/Key Laboratory of Eco-Environment in Three Gorges Region (Ministry of

Education), Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing, 400715, People’s Republic of China Banglin Luo, Jiangwen Li, Chaofu Wei & Shouqin Zhong * District

Agro-Tech Extension and Service Center of Shapingba, Chongqing, 400000, China Jiahong Tang * Key Laboratory of Arable Land Conservation (Southwestern China), Ministry of Agriculture,

Chongqing, 400715, China Chaofu Wei & Shouqin Zhong * State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China Chaofu Wei 

& Shouqin Zhong Authors * Banglin Luo View author publications You can also search for this author inPubMed Google Scholar * Jiangwen Li View author publications You can also search for

this author inPubMed Google Scholar * Jiahong Tang View author publications You can also search for this author inPubMed Google Scholar * Chaofu Wei View author publications You can also

search for this author inPubMed Google Scholar * Shouqin Zhong View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS Conceptualization, B.L. and

J.L.; investigation and data curation, B.L., J.L. and J.T.; methodology and formal analysis, B.L., J.L. and J. T.; writing-original draft preparation, B.L.; writing-review and editing, J.L.,

C.W. and S.Z.; project administration and supervision, C.W. and S. Z.; funding acquisition, C.W. and S.Z. CORRESPONDING AUTHORS Correspondence to Chaofu Wei or Shouqin Zhong. ETHICS

DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. ADDITIONAL INFORMATION PUBLISHER'S NOTE Springer Nature remains neutral with regard to jurisdictional claims

in published maps and institutional affiliations. RIGHTS AND PERMISSIONS OPEN ACCESS This article is licensed under a Creative Commons Attribution 4.0 International License, which permits

use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the

Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless

indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory

regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit

http://creativecommons.org/licenses/by/4.0/. Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Luo, B., Li, J., Tang, J. _et al._ Microtopography effects on pedogenesis in the

mudstone-derived soils of the hilly mountainous regions. _Sci Rep_ 14, 11998 (2024). https://doi.org/10.1038/s41598-024-62540-y Download citation * Received: 20 January 2024 * Accepted: 17

May 2024 * Published: 25 May 2024 * DOI: https://doi.org/10.1038/s41598-024-62540-y SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get

shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative KEYWORDS * Pedogenic

characteristics * Physicochemical property * Mudstone * Microtopography * Mineralogy * Toposequence