Exploring Nano-Calcium Phosphate for Sustainable Rice Farming in Arsenic- Contaminated Fields

Background Phosphorus (P) is essential for plant growth and agricultural productivity, but its scarcity limits crop yields. This study evaluates the efficacy of composite nanocalcium phosphate (NCaP) and hydroxyapatite nanoparticles (HANPs) as alternatives to conventional diammonium phosphate (DAP) fertilizers for rice crops in arsenic (As)-contaminated fields in Ghazipur and Jaunpur, Uttar Pradesh. HANPs were characterized as 15-45 nm particles with a Ca/P ratio of 1.7. Results Growth Metrics and Yield: Panicle Length was Increased by 1.8%-4.5% with NCaP treatments. Grains per Panicle was enhanced by 4.9%-6.6%.1000-Grain Weight was elevated by 10.6%-28%. Fertile Spikelet Count was improved by 4.9%-8.4%. Plant Health: Electrolytic Leakage and Lipid Peroxidation was decreased, indicating better membrane health. Pigment Content was improved, reflecting enhanced chlorophyll levels. MDA Production was reduced by 21%-30% in shoots with NCaP applications. Significant variances in activities of APX, GPX, SOD, and CAT were observed. Significant reduction was observed in grain As accumulation with NCaP treatments compared to control. Elevated P levels in roots, shoots, and grains of NCaP-treated plants was noticed. Highest concentration of 23 mg g⁻¹ observed in T2 treated plants. Conclusions The study demonstrates that NCaP nanoparticles can effectively replace traditional DAP fertilizers, enhancing rice crop growth, yield, and health while mitigating arsenic contamination. NCaP treatments resulted in improved growth metrics, reduced oxidative stress, and higher phosphorus concentrations in plants, highlighting the potential of nanotechnology in advancing sustainable agriculture and increasing productivity.