Synergistic Effects of K and B Foliar Applications on Sugar Beet Productivity and Quality under Saline Soil Conditions.

Soil salinity is a major threat to crop production, particularly in arid regions like Egypt. This study investigated the impacts of single and combined foliar applications of K and B to increase the growth and productivity of sugar beet under salinity conditions. To achieve this aim, sugar beet was grown for two consecutive years under field conditions on soil with salinity levels slightly exceeding the threshold tolerance of the crop. The experimental design followed a split-plot layout, with four levels of foliar potassium (K) application (0, 1.34, 1.79, and 2.68 kg K ha-1) as the main plots, and four levels of boron (B) application (0, 3.6, 4.8, and 7.1 L ha-1) as subplots. The key results indicate that the moderate doses of these two nutrients (1.34 kg K/ha and 3.6 L B/ha) significantly enhanced tuber yields by 12-18% over controls, while higher rates exhibited diminishing returns. The combination of 2.68 kg K/ha + 7.1 L B/ha synergistically maximized sugar beet productivity by 15-24% and foliage by 20.5-23.25%. It also enhanced tuber quality by 6.3-7.8% and boosted its length and diameter. The mechanism underlying such increases was mostly related to the concurrent increases in K+/Na+ ratios in roots by 16-51% and sucrose content by 15%. In conclusion, this dual application of K and B (2.68 kg K/ha + 7.1 L B/ha) could be an important strategy to mitigate salinity stress on sugar beet, aligning with the UN sustainable developmental goals: SDG 2 and SDG 13. [ABSTRACT FROM AUTHOR]