Effect of land management intensity on soil quality of Andisol in the Upper Brantas Watershed, Batu, Indonesia

Soil quality plays an important role in maintaining agricultural productivity, land conservation, and ecosystem resilience, especially in volcanic landscapes such as the Upper Brantas Watershed. This study assesses the impact of land management intensity (LMI) on the soil quality index (SQI) across varying land-use types and slope gradients. Using a stratified random sampling approach, soil samples were analysed for physical and chemical properties, while LMI was evaluated based on input intensity and soil conservation practices. Statistical analyses, including ANOVA and correlation analysis, were performed to determine the relationships among LMI, vegetation biomass, and SQI. The results revealed a negative correlation between LMI and SQI. The highest soil quality was observed in protected forests (SQI = 0.64–0.76; biomass = 541.4–675.2 Mg∙ha⁻¹) and pine–coffee agroforestry systems (SQI = 0.57–0.65; biomass = 387.1–475.7 Mg∙ha⁻¹). In contrast, upland farming (LMI = 0.68–0.71; SQI = 0.37–0.52) and pine–horticulture agroforestry (LMI = 0.50–0.56; SQI = 0.40–0.51) exhibited the lowest soil quality. Steeper slopes are associated with greater soil degradation, particularly in regions of intensive activity. These findings demonstrate that intensive land management accelerates soil degradation, while agroforestry and conservation-oriented land uses enhance soil health through increased organic matter inputs and reduced soil disturbance. The study underscores the importance of adopting sustainable land management strategies such as mulching, minimum tillage, and terracing to mitigate soil degradation. These insights are crucial for policymakers and land managers in developing effective soil conservation programs for sustainable watershed management.