the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
How do Microtopography Act in the Pedogenic Characteristics of Mudstone-derived Soils in Hilly Mountainous Regions?
Banglin Luo
Jiangwen Li
Jiahong Tang
Chaofu Wei
Shouqin Zhong
Abstract. The topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are defined as microtopographies. As a characteristic topographic condition 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 and developed into hill landforms by erosion of flowing water. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physiochemical, and geochemical attributes of profiles were analysed. The results showed that the soil thickness increased significantly with changes in the soil profile configuration from the summit to the toeslope, and the profile configuration changed from A-C to A-B-C. The migration direction of Ca and Na at the summit, backslope, and footslope changed from enrichment to leaching, whereas that of Al, Fe, and Mg changed from leaching to enrichment. At the summit and shoulder of the hillslope, weathered materials are transported away by gravity and surface erosion, and new rocks are often exposed; therefore, the characteristics of soil development is relatively weak. However, in flat areas such as the footslope and toeslope with sufficient water conditions, the long-term contact between water, soil, and sediment leads to further chemical weathering, resulting in highly developed characteristics. Microtopography can affect physicochemical properties, chemical weathering, and redistribution of water and materials, resulting in differences in pedogenic characteristics at different slope positions.
Banglin Luo et al.
Status: open (until 22 Apr 2023)
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CC1: 'Comment on egusphere-2022-1352', gangcai liu, 27 Feb 2023
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The spatial heterogeneity of slope soil in hilly region is very obvious. Through field investigation and sampling analysis, the author revealed the formation mechanism of the spatial heterogeneity of slope soil, which provides a new scientific basis for the improvement and management of slope soil in the study area. Therefore, this study has obvious innovation and scientific value.
Citation: https://doi.org/10.5194/egusphere-2022-1352-CC1 -
AC1: 'Reply on CC1', Chaofu Wei, 07 Mar 2023
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Thanks very much for your approval of this research, we will continue to work hard.
Citation: https://doi.org/10.5194/egusphere-2022-1352-AC1
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AC1: 'Reply on CC1', Chaofu Wei, 07 Mar 2023
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CC2: 'Comment on egusphere-2022-1352', Ningxiang Ouyang, 03 Mar 2023
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The terrain significantly impacts soil development, especially in soil morphology and physical and chemical properties. The manuscript studies the influence of microtopography on soil genesis by using soil samples formed by lacustrine sedimentary mudstones in the central Sichuan Basin. This is a good study, and its results are of considerable interest. Some minor revisions are list below.
Line166 Is the author comparing the RR value of B horizon soil at different slope positions?
Line194 The soil organic carbon content in layer B increased with the decrease in altitude. This conclusion is very interesting. Can the author explain the reason in detail?
Citation: https://doi.org/10.5194/egusphere-2022-1352-CC2 -
AC3: 'Reply on CC2', Chaofu Wei, 07 Mar 2023
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Thanks very much for your valuable comments on our research paper. After careful consideration, we maked the following reply:
Question 1: Line 166 compared the averages RR values for each profile horizon of the footslope and toeslope. A decreasing trend from the summit to the toeslope was observed in all horizons, and the RR values of the footslope and toeslope were similar. Thus, the RR values of horizon B were not described separately; instead, an overall description was provided in lines 168-170.
Question 2: Due to soil erosion, the surface soil with a high content of SOC at higher topography was detached, transported, and deposited along the slope. This gradual increase in soil thickness also led to the accumulation of SOC in horizon B. The leaching of dissolved organic carbon (DOC) in horizon A also contributed to the increase of SOC in horizon B. At the same time, compared to horizon A, horizon B was less affected by tillage and had lower microbial content. This allowed for more SOC to be preserved rather than mineralized by microorganisms, resulting in a relative enrichment of SOC.Â
Thanks again for your constructive comments. If you have any questions, please do not hesitate to contact us.
Citation: https://doi.org/10.5194/egusphere-2022-1352-AC3
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AC3: 'Reply on CC2', Chaofu Wei, 07 Mar 2023
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CC3: 'Comment on egusphere-2022-1352', Youjin Luo, 06 Mar 2023
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Topography is a key factor that controls soil genesis and strongly influences the physicochemical properties. The manuscript studies the influence of microtopography on soil genesis by using soil samples formed by lacustrine sedimentary mudstones in the central Sichuan Basin, to clarify the effect of microtopography on pedogenic characteristics. This is a very interesting topic for further understanding of regional soil formation has scientific value.
Citation: https://doi.org/10.5194/egusphere-2022-1352-CC3 -
AC2: 'Reply on CC3', Chaofu Wei, 07 Mar 2023
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Thanks very much for your attention to this study. If there are any questions about this paper later, please do not hesitate to contact us.
Citation: https://doi.org/10.5194/egusphere-2022-1352-AC2
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AC2: 'Reply on CC3', Chaofu Wei, 07 Mar 2023
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Banglin Luo et al.
Banglin Luo et al.
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