Soil and water conservation practices (SWCPs) play a crucial role in mitigating soil erosion, a global environmental challenge. However, their effectiveness varies across basins, and traditional design approaches often neglect heterogeneity within sub-basins, overlook farmers' preferences, and fail to consider the trade-offs between environmental benefits and economic costs. This study proposes a novel multi-objective optimization framework that integrates ecosystem service value (ESV) and life-cycle investment costs (IC) to optimize the layout of SWCPs at the sub-basin scale, using the Soil and Water Assessment Tool (SWAT) model coupled with a non-dominated sorting genetic algorithm. Fifteen SWCP scenarios (four individual and eleven combined) were evaluated based on their effects on streamflow (SF), sediment yield (SY), IC, and ESV. Results demonstrate that combined SWCPs lead to greater reductions in SF and SY than individual measures, with the combination of terracing, contour farming (CFA), and boulder check dams producing the highest reductions. Although higher IC generally corresponds to greater decreases in SF and SY, low-cost practices like CFA still offer significant benefits despite their lower ESV. The findings emphasize the necessity of balancing SF/SY reductions with IC and ESV, as strategies focused solely on minimizing SF/SY may lead to suboptimal outcomes. The optimized solution reduces SF by 36.84×10 5 m 3 and SY by 44.96×10 4 t, with a minimal IC of 4.61×10 6 CNY, while generating an ESV of 64.16×10 6 CNY. These findings offer valuable guidance for farmers and policymakers in selecting optimal SWCP configurations that balance cost efficiency, erosion control, and ecosystem service enhancement.
Li et al. (2026) studied this question.