Influence of parent material-driven soil physicochemical variability on rice productivity in East Java

Changes in soil management addressing physicochemical constraints linked to parent materials are essential for achieving optimal rice yields in East Java Province. This study evaluated the spatial variability of soil physicochemical properties across rice fields and identified appropriate management strategies. Semi-detailed soil mapping (1:50,000 scale) was integrated with spatial paddy field data, and representative soils from different parent materials were analyzed. Results indicated that soil variability and rice yield were strongly influenced by parent material. Soils derived from fine alluvial deposits (Typic Endoaquerts) exhibited high clay content, elevated phosphorus and potassium levels, high cation exchange capacity (CEC), and balanced base cations, resulting in the highest yields (7.71 t ha-¹). In contrast, soils developed from marine and calcareous sediments (Sodic Endoaquents and Vertic Haplustepts) had low soil organic carbon (SOC), low CEC, nutrient imbalances, and salinity risk, with yields below 4.5 t ha-¹. Phosphorus availability was identified as the primary factor influencing yield, followed by SOC, nitrogen (N), magnesium (Mg), and CEC. These findings support the development of site-specific soil management strategies to optimize fertilizer use, enhance soil quality, and sustainably improve rice productivity.