Foliar fertilization with potassium silicate enhances water productivity and drought resilience in sugar beet

Sugar beet ( Beta vulgaris L.) is an essential industrial crop valued for its sugar production, especially in regions with limited water resources. Due to its lower water demands, sugar beet is favored over sugarcane in Egypt. We hypothesized that foliar application of potassium silicate (K₂SiO₃) would enhance sugar beet's physiological responses, yield, and water productivity under drought and saline conditions, offering an eco-friendly solution to optimize crop performance in semi-arid regions. This study aimed to (i) investigate the impact of foliar-applied K 2 SiO 3 on the physiological, biochemical, and anatomical traits of sugar beet under drought stress in saline soils, (ii) evaluate the effects of K 2 SiO 3 on agronomic traits, root and sugar yields, and water productivity under different irrigation regimes, and (iii) assess K 2 SiO 3 to mitigate the adverse effects of drought and salinity, enhancing sugar beet resilience and productivity. Field experiments were conducted over two winter seasons at Fayoum University, Fayoum, Egypt, to assess the impact of three irrigation regimes (DIR 0% , DIR 25% , DIR 50% ) and three foliar K₂SiO₃ concentrations (0, 10, 20 mmol L −1 ) on sugar beet (cv. Baraca) in a split-plot arrangement based on a randomized complete block design (in triplicates). Physiological parameters, such as leaf water content, membrane stability, chlorophyll fluorescence, osmolyte accumulation, and antioxidant enzyme activities, were measured. Agronomic traits, including root yield, white sugar yield, and crop water productivity (WPc), were also evaluated. In general, drought stress negatively impacted physio-biochemical and anatomical traits, nutrient uptake, growth, sugar yield, and quality of sugar beet. This was evidenced by the significantly ( P <0.05) increased levels of osmolytes and antioxidants (enzymatic and non-enzymatic), which indicated the plant’s defensive/adaptive responses to drought stress. However, K 2 SiO 3 effectively alleviated the adverse effects of deficit irrigation. Notably, the interaction of DIR 0% × KSi-20 resulted in the highest root yield (88.97 t ha −1 ) and sugar yield (14.43 t ha −1 ), while the highest WPc (24.48 kg m −3 ) was achieved in the DIR 50% × KSi-20 treatment. Foliar application of K₂SiO₃ effectively alleviates drought and salinity stress in sugar beet by improving physiological and biochemical traits. The treatment enhances photosynthetic efficiency, osmolyte accumulation, antioxidant activity, and nutrient uptake, leading to improved crop yield and quality. This study highlights K₂SiO₃ as a cost-effective, eco-friendly strategy to enhance sugar beet resilience in arid and saline environments. Integrating K₂SiO₃ into crop management practices could contribute to sustainable sugar production, particularly in regions facing water scarcity and soil salinity challenges.