Calcareous soil modified with metallic and organic ZnO nanoparticles limits photosynthetic pigment accumulation and macronutrient uptake in Swiss chard (Beta vulgaris var. cicla)

Previous studies on the effects of zinc oxide nanoparticles have mainly examined controlled agricultural settings, failing to consider their behavior in real agricultural soil. As a result, our knowledge of their environmental impact remains incomplete. This study was specifically developed to observe the comparative effects of metallic zinc oxide nanoparticles, zinc sulfate, and zinc oxide green nanoparticles at different concentrations (25, 50, 75 and 100 mg of Zn kg⁻¹ of soil) on growth parameters, the mineral content (N, P, K and Zn) in root and leaf, the content of chlorophyll a (CHLa), b (CHLb), and total (CHLt), and carotenoids in Swiss chard plants grown in calcareous soil. Leaf area and dry root weight increased by 23.27 % and 46.20 %, respectively, in zinc sulfate modified soil. Total chlorophyll and carotenoids also increased by 40.12 % and 32.59 %. The concentration of N, P, K and Zn in roots was 2.89, 1.74, 1.70 and 1.52 times higher, while in leaves, the concentration was 1.48, 1.44, 1.76 and 2.22 times higher in plants grown with zinc sulfate. The effects on plant growth can be attributed to the type of fertilizer used and its influence on macronutrient absorption in the soil. The utilization of zinc sulfate as a soil treatment led to elevated absorption of macronutrients and zinc, suggesting a connection between the fertilizer type and the crop’s agronomic and physiological reactions.