PurposeEnhancing zinc (Zn) bioavailability in soil is vital for improving crop nutrition and human health, especially in Zn-deficient regions. This study evaluated the effect of conservation agriculture-based nutrient management practices in a rice-wheat system on Zn bioavailability in the soil solution. Soil samples were collected from a long-term experiment (started in June 2020) of five scenarios: farmers' practice (FP), partial conservation agriculture (CA) with inorganic source of N (NI), partial CA with organic source of N (NO), partial CA with integration of organic and inorganic source of N (NO+I), and full CA + NI.MethodsBatch adsorption isotherm, thermodynamics, and kinetic experiments assessed Zn's maximum adsorption capacity (Qm), interaction mechanisms, bioavailability, and plant uptake.ResultsZn adsorption in soil was spontaneous and best described by the Langmuir isotherm at both 25 degrees C and 40 degrees C. The maximum adsorption capacity (Qm) reached to 1155.51 +/- 51.38 mg kg-1 at an equilibrium concentration of 20 mg L-1 at 40 degrees C, and decreased with temperature. The application of Zn fertilizer enhanced adsorption due to a higher concentration gradient. Kinetic modelling confirmed that Zn adsorption occurred primarily through covalent bonding at both temperatures across all scenarios, with organic matter-devoid soils also favouring covalent interaction but at slower adsorption rates. The organic inputs increased sorption efficiency but reduced the bonding energy (KL), facilitating easier Zn release for plant uptake. Therefore, partial CA + NO+I and partial CA + NO exhibited higher total Zn uptake in rice plants. Conversely, full CA + NI showed the maximum distribution coefficient (Kd: 1550.72 +/- 168.22 L kg-1), but its stronger bonding (KL: 2.53 +/- 0.70 L mg-1 at 40 degrees C) limited Zn bioavailability and reduced Zn uptake in rice plants.ConclusionWhile long-term adoption of partial conservation agriculture with integrated nutrient management significantly enhanced zinc bioavailability in semi-arid, high-temperature rice-wheat systems, soil minerals and organic matter contributed to the zinc adsorption in soil. This improved zinc availability not only boosts crop nutrition and yield stability but also contributes to addressing Zn-malnutrition through zinc-enriched cereals. Integrating CA with integrated nutrient management practices into agricultural policy can advance multiple national goals- climate-resilient farming, soil health restoration, and food and nutrition security. Strategic interventions, including financial support, extension services, and research investments, are essential to scale these practices across zinc-deficient regions of the Indo-Gangetic Plains.