Fine-scale erosion under soil conservation practices: selective sediment transport and runoff in terraced and non-terraced no-till hillslopes

Purpose This study quantified sediment losses under no-till management with and without agricultural terraces and to evaluate the particle-size distribution of sediment exported during rainfall–runoff events. Materials and methods The study was conducted in two macroplots, with an average area of 1.54 ha each, under no-till management: one with agricultural terraces (NT + T) and the other without terraces (NT), located in the east-central region of Paraná State, Brazil. A total of 24 rainfall–runoff events were monitored between 2023 and 2025. Rainfall was recorded using a pluviograph, and surface runoff and suspended sediment concentrations were sampled at an H-flume. Total sediment yield and particle-size distribution of the transported sediment were subsequently determined. Hydrosedimentological variables were compared using the nonparametric Wilcoxon test, while particle-size distribution was evaluated using confidence intervals. Results and discussion The NT system exhibited higher runoff volumes and greater sediment losses. In contrast, the NT + T treatment significantly reduced both runoff and sediment yield, and no surface runoff was observed during lower-intensity rainfall events. Particle-size analysis indicated a predominance of the silt-equivalent fraction (2–50 μm), with no significant differences between macroplots. This result highlights the selective nature of the erosion process and underscores the environmental risks associated with the transport of fine particles, which are more prone to carrying nutrients and contaminants. Conclusions No-till management combined with agricultural terracing was effective in mitigating water erosion, contributing to soil and water conservation and enhancing the sustainability of agricultural production on sloping land.