To address the issues of “over-liming” and “under-liming” arising from within-field soil heterogeneity during the amelioration of acidity in newly reclaimed red soils in southern China, this study investigated a 10-mu (about 0.67 ha) reclaimed red soil farmland in Jizhou District, Ji’an City, Jiangxi Province. Soil samples were collected using a grid sampling design, and soil pH, pH buffering capacity (pHBC), and lime requirement (LR) were determined. Descriptive statistical analysis combined with ordinary Kriging spatial interpolation was employed to characterize the spatial heterogeneity of acidity-related indicators at the field scale, and microtopographic factors were further incorporated to explore their potential driving mechanisms. Results showed that soil pH averaged 4.73 with a coefficient of variation (CV) of 3.53%, indicating low variability. The mean ΔpH (the difference between the target pH of 5.5 and the initial pH) was 0.77 (CV=21.74%, moderate variability). The average pHBC was 2.78 cmol/kg/pH (CV=6.65%, low variability), whereas the mean LR was 2.35 t/ha (CV=25.38%, moderate variability), indicating the LR exhibited the most pronounced spatial heterogeneity. Spatially, soil pH displayed a patchy distribution, with higher values in the central and southern parts of the field. High pHBC values were mainly concentrated in the central and southwestern areas, while the spatial pattern of LR was inversely related to that of pH, with low-pH areas corresponding to higher lime requirements. Pearson correlation analysis indicated that LR was significantly negatively correlated with pH (R2=0.94, P<0.001) and significantly positively correlated with pHBC (R2=0.37, P<0.001), suggesting that LR is jointly controlled by both soil acidity and buffering capacity. The “higher in the east and lower in the west” terrain pattern, together with variations in slope and curvature, exerted an important influence on the spatial distribution of soil pH and LR by regulating water movement and base cation redistribution. Specifically, relatively higher and well-drained areas tended to exhibit lower pH and higher LR, whereas low-lying and water-converging areas showed higher pH and lower LR. These findings highlight that acidity amelioration in newly reclaimed red soils should account not only for the spatial heterogeneity of pH and pHBC, but also for microtopographic variability to implement zone-specific precision management. Integrating rapid LR determination techniques with intelligent lime-application equipment can facilitate the transition from experience-based to data-driven precision management, thereby providing a scientific basis and technical support for the efficient amelioration of acidic newly reclaimed red soils in southern China.