Improving regional soil erosion assessment accuracy by integrating the oblique cross-slope tillage subfactor

Abstract

Regional soil erosion mapping is crucial for understanding erosion patterns and guiding conservation planning. The ridge–furrow direction is an important factor influencing soil erosion and can be quantified using the oblique cross-slope tillage subfactor (T_o). However, T_o has often been overlooked in regional assessments because of data and computational challenges. In this study, a novel methodology was introduced for calculatingT_o on a regional scale, including sample unit design, parcel-by-parcel furrow direction surveys, grid-by-grid T_o calculations, and interpolation to obtain regional T_o values. Using Northeast China (1.432 million km²) as a case study, 945 sample units (small watersheds of about 1 km² each) were designed based on a stratified systematic area sampling method. In total, 6,679 erosion parcels were delineated, and 7,283 tillage lines were digitized to calculate T_o. Soil erosion rates were assessed using the proposed method and compared with regional assessments that neglected T_o, with detailed survey-based T_o estimates within the sample units used as the reference values. The results showed that neglecting T_o led to a 30.1 % overestimation, whereas the proposed regional method reduced this overestimation to 6.3 %. The average T_o value across the study region was 0.805, and its distribution was closely related to topography, with higher values in gentler areas and lower values in steeper areas. These findings provide valuable guidance for soil conservation planning: maintaining north–south tillage in areas with slopes < 0.5°, adopting more contour tillage for slopes between 0.5° and 5°, and implementing terracing or additional measures on slopes &gt; 5°. The incorporation of T_o into regional soil erosion assessments is crucial, and the proposed method provides an effective and practical solution.

Keywords

Regional soil erosion mapping / CSLE / Furrow direction / Contour tillage / Oblique cross-slope tillage

Data availability

Data will be made available on request.

Declaration of competing interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Lixia Dong: Writing – original draft, Visualization, Methodology, Investigation, Formal analysis, Data curation.

Baoyuan Liu: Writing – review & editing, Visualization, Methodology, Funding acquisition, Formal analysis, Conceptualization.

Acknowledgements

This work was supported by the National Key R&D Project of China (Grant No. 2021YFD1500704) and the China Postdoctoral Science Foundation (Grant No. 2025M780299).

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