Enhancing sugar beet growth and quality using green-synthesized nanofertilizers: a comparative study of seed priming and foliar spraying

This study evaluated the effects of foliar spraying and seed priming with green-synthesized nanofertilizers (NFs) containing silver (Ag), zinc oxide (ZnO), and an Ag/ZnO composite on the growth and quality of two sugar beet (Beta vulgaris L.) varieties, Kawemira and Dema Poly. The experiment was conducted under greenhouse conditions at El-Sabahia Research Station, Alexandria, Egypt (31°12'N, 29°58'E) using a randomized complete block design (RCBD) with five replicates in 50 cm earthenware pots. Treatments included foliar sprays or seed priming at 0 (control), 50, and 100 ppm, applied at different growth stages. Foliar application of AgNFs at 100 ppm, 15 days after sowing, achieved the highest fresh shoot weights (240 g in Kawemira, 231 g in Dema Poly) and root weights (995.6 g in Kawemira, 984 g in Dema Poly). Seed priming with Ag/ZnONFs composite at 50 ppm for 24 h resulted in high shoot weights (240 g and 241 g) and root weights (902 g and 865 g) for Kawemira and Dema Poly, respectively. Foliar spraying with Ag/ZnONFs composite at 50 ppm increased total soluble solids (TSS) to 28.8% (Kawemira) and 30.8% (Dema Poly), and sucrose content to 21.25% and 22.25%, respectively. The formation and elemental composition of AgNFs, ZnONFs, and Ag/ZnONFs composites were confirmed via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). These findings demonstrate that targeted use of green-synthesized nanofertilizers can significantly improve sugar beet growth, sugar content, and juice quality. The results highlight the potential of nanofertilizer application particularly seed priming as a sustainable and cost-effective approach for enhancing crop productivity.