<p>The application of carbon nanoparticles (CNPs) derived from carbon black in agriculture provides alternative solutions for sustaining global food security in a changing climate. Most of the existing studies were conducted under controlled conditions, which can rarely reflect CNPs’ performance and impacts in real-world agricultural settings. To address the knowledge gap, a two-year field experiment was conducted. CNPs (pH: 5.5, particle diameter: 20–130&#xa0;nm, zeta-potential: -40.6&#xa0;mV) were applied as soil amendments at different application rates (0, 100, 200, 400, and 600&#xa0;mg&#xa0;kg⁻¹ soil) along with fertilizers. Plots with only fertilizers were used as controls. The changes in plant height, chlorophyll content, grain yield, nutrient uptake, and soil biochemical properties were determined to study the effectiveness and optimal application rates of CNPs for improving corn (<i>Zea mays L.</i>) growth and nutrient uptake in acidic sandy soil. The results showed that CNPs applied ≥ 400&#xa0;mg&#xa0;kg⁻¹ significantly increased corn yield (22.6–23.2%). The nutrient use efficiency of N, P, and K increased from 28.7, 14.5, and 32.6% to 38.2, 22.2, and 60.6% by 400&#xa0;mg&#xa0;kg⁻¹ CNPs, respectively. Plant uptake of other nutrients was also enhanced by CNPs with a maximum increase of 127% for Ca, 86% for Mg, 88.9% for Fe, and 43.4% for Mn, respectively. The application of CNPs significantly increased most soil available nutrients (P, K, Ca, Mg, Fe, Mn), indicating CNPs increase plant nutrient uptake by maintaining more available nutrients in the soil from leaching. These results facilitate bridging the knowledge gap of CNPs’ agronomic efficiency in greenhouse and field conditions, indicating that CNPs derived from carbon black could be a cost-effective soil amendment for improving nutrient uptake and crop yield.</p> Graphical Abstract <p></p>