Dalbianco et al. (2026) Water infiltration and saturated hydraulic conductivity in an agricultural watershed with pedogenetic discontinuity

Identification

• Journal: Scientific Reports
• Year: 2026
• Date: 2026-04-02
• Authors: Leandro Dalbianco, Jean Paolo Gomes Minella, Gizachew Ayalew Tiruneh, José Miguel Reichert
• DOI: 10.1038/s41598-026-46420-1

Research Groups

• Soils Department, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
• Department of Natural Resource Management, Debre Tabor University, Debre Tabor, Ethiopia
• Soils Department, Federal University of Pelotas (UFPel), Santa Maria, RS, Brazil

Short Summary

This study investigates soil hydraulic properties, including infiltration and saturated hydraulic conductivity, across different hillslopes and soil layers in a tobacco-cultivated watershed characterized by pedogenetic discontinuities. It reveals significant spatial heterogeneity in these properties, with surface layers showing the highest conductivity due to tillage, and highlights the critical influence of pedogenetic discontinuities on hydrological response.

Objective

• To investigate soil hydraulic properties (granulometry, bulk density, water retention, steady-state infiltration rate (Is), and saturated hydraulic conductivity (Ksat and Keff)) across different hillslopes, slope positions, and soil layers within a tobacco-cultivated agricultural watershed with pedogenetic discontinuity.

Study Configuration

• Spatial Scale: An agricultural watershed, specifically a tobacco-cultivated watershed, encompassing different hillslopes, slope positions, and soil layers.
• Temporal Scale: Field measurements and laboratory analyses conducted at a specific point in time to characterize soil hydraulic properties.

Methodology and Data

• Models used: No specific hydrological simulation models were explicitly used in this study. The methodology focused on direct measurement and characterization of soil properties.
• Data sources:
  • Field measurements of steady-state infiltration rate (Is).
  • Laboratory analyses of soil samples for granulometry, bulk density, water retention (from saturation to permanent wilting point), and saturated hydraulic conductivity (Ksat and Keff).

Main Results

• Saturated hydraulic conductivity (Ksat) ranged widely from 0 to 1.075 × 10⁻⁴ meters per second (0 to 387 millimeters per hour).
• The highest Ksat values were consistently found in surface layers, attributed to intense tillage practices associated with tobacco ridge construction.
• Steady-state infiltration rate (Is) showed high variability, ranging from 1.11 × 10⁻⁶ to 1.117 × 10⁻⁴ meters per second (4 to 402 millimeters per hour).
• Effective saturated hydraulic conductivity (Keff) also varied significantly, from 0 to 6.22 × 10⁻⁵ meters per second (0 to 224 millimeters per hour).
• Acrisols exhibited some low infiltration values, while midslope positions generally showed higher Is across different soil types.
• A linear relationship was observed between Keff and Is (coefficient of determination, r² = 0.67).
• Ksat of the surface soil was not found to be related to Is.
• More permeable soils (higher Ksat) were associated with lower bulk density and reduced water retention under both wet and dry conditions.
• In surface layers, Ksat correlated positively with water retention near field capacity.
• Keff related directly to Is and gravel content but inversely to water retention at the permanent wilting point.
• Is correlated positively with fine sand content and saturation water retention, and negatively with bulk density.
• The observed spatial heterogeneity in soil hydraulic properties reflects the combined influence of texture, compaction, land use, and microtopography in sloped terrains.
• Pedogenetic discontinuities significantly shape soil horizon development and hydrological response, particularly under saturated conditions.

Contributions

• Provides an enhanced understanding of soil hydraulic properties in complex agricultural landscapes characterized by pedogenetic discontinuities and gravelly soils.
• Quantifies the impact of specific agricultural practices (e.g., tobacco farming tillage) on surface soil hydraulic conductivity.
• Highlights the critical importance of incorporating factors like pedogenetic discontinuities, texture, compaction, land use, and microtopography into hydrological models and watershed management strategies.
• Improves the prediction of infiltration, runoff, and chemical transport, thereby aiding in better land and soil management, especially for mitigating subsurface erosion risks in similar environments.

Funding

• Coordination for the Improvement of Higher Education Personnel (Capes)
• SindiTabaco (Finance code 001)

Citation

@article{Dalbianco2026Water,
  author = {Dalbianco, Leandro and Minella, Jean Paolo Gomes and Tiruneh, Gizachew Ayalew and Reichert, José Miguel},
  title = {Water infiltration and saturated hydraulic conductivity in an agricultural watershed with pedogenetic discontinuity},
  journal = {Scientific Reports},
  year = {2026},
  doi = {10.1038/s41598-026-46420-1},
  url = {https://doi.org/10.1038/s41598-026-46420-1}
}