Nitrogen-boron in wheat: yield optimization and soil fertility in Nepal

Abstract Background Nitrogen (N) and boron (B) are essential for optimal wheat growth and development; however, their imbalanced application may compromise yield and soil fertility. Despite their importance, limited studies have addressed their interactive effects. This study aimed to evaluate the combined influence of N and B fertilization on wheat yield and residual soil chemical properties to inform sustainable nutrient management strategies. Methods The experiment was conducted during the 2020–2021 cropping seasons in Dhading, Nepal, with a split-plot design using the variety BL3063. The main plots received N application levels (0, 80, 100, and 120 kg ha⁻¹), while the subplots were treated with B levels (0, 1, and 2 kg ha⁻¹), replicated three times. Soil physico-chemical properties and crop phenological parameters were measured to assess the effects of N and B applications on wheat performance and soil health. Results N application significantly enhanced grain yield, biological yield, and straw yield, with the highest grain yield observed at 120 kg N ha⁻¹ (8143.89 kg ha⁻¹), a 49.3% increase compared to the control (5455.87 kg ha⁻¹). In both 2020 and 2021, N application also significantly increased tissue N concentration at all phenological stages, with the greatest accumulation recorded during tillering under 120 kg N ha⁻¹, confirming a clear dose-specific and phenological response. B application notably reduced spikelet sterility and improved grain yield. The lowest sterility rate (33.2%) was observed under the application of 120 kg N ha⁻¹ and 2 kg B ha⁻¹, representing a 35.9% reduction compared to the control treatment (51.8% sterility at 0 kg B ha⁻¹ and 0 kg N ha⁻¹). Indicating a synergistic interaction that improved reproductive success. Soil analysis revealed that N application reduced soil pH especially in 2021 while total N content increased with higher N rates. B availability was significantly influenced by B treatments, with year-to-year variation. Conclusion Strategic N and B management can enhance wheat productivity while maintaining soil fertility. Applying both nutrients in a balanced manner can optimize yield. Long-term research is needed to develop sustainable fertilization strategies and assess the effects on soil properties. Integrating micronutrient management into nutrient recommendations is essential for improving wheat profitability.