Biochar mitigates salt stress by regulating phytochemical and physiological traits of triticale

In arid areas, increasing water salinity driven by water scarcity adversely affects plant performance; however, biochar application is a promising approach to increase salt tolerance. To investigate the impact of different crop residues and their biochars on the phytochemical and physiological traits, ion uptake, and yield attributes of salt-stressed triticale, a pot experiment was conducted under greenhouse conditions. The first factor was salinity stress, induced by sodium chloride (NaCl), at three levels [without salt (S0), salt stress with an electrical conductivity (EC) of 8 dS m− 1 (S8), and an EC of 12 dS m⁻¹ (S12)]. The second factor was amendment type including control (without amendment), wheat residue (WR), wheat residue biochar (WRB), sesame residue (SR), and sesame residue biochar (SRB) each applied at 2% (w/w). Salt stress significantly reduced chlorophyll a in all the amendments, although the decline in the SRB and WRB was notably lower than that in the SR and WR. Under S8 in the SRB and WRB, the total chlorophyll increased by 55.0 and 50.0%, respectively compared to WR. The carotenoid content decreased by 264.7% in S12 relative to that in S0. SRB increased the catalase (CAT) and peroxidase (POX) activity, leaf relative water content (RWC) and remobilization efficiency in each salt stress. In each salinity level, SRB and WRB reduced proline content more than other treatments. SRB presented the greatest number of grains spike⁻¹, with increases of 24.7% to 93.7%.In S12, compared with the control, SRB application doubled the grain yield. SRB and WRB revealed the better performance in improving K+/Na+ ratio, as well. Overall, SRB enhanced grain yield in triticale by improving photosynthetic pigments, RWC, plant height, number of grains spike− 1, and the K⁺/Na⁺ ratio, underscoring its value in sustainable agricultural systems.