Antimony (Sb) toxicity is a serious concern across the globe due to its hazardous impacts on plants and living organisms. The co-application of Chinese milk vetch (CMV) and biochar (BC) is a common agricultural practice, however, the effects of combined CMV and BC in mitigating Sb toxicity and bio-availability remain unclear. Therefore, this study investigated the impacts of CMV, rape straw biochar (RBC), and iron-modified biochar (FMB) and their combinations on rice productivity, physiological, and biochemical functioning of rice and Sb availability. Antimony toxicity caused a marked reduction in rice growth and productivity by decreasing chlorophyll, and anthocyanin synthesis, leaf water contents, osmolyte synthesis and antioxidant activities while, increasing hydrogen peroxide (H₂O₂), electrolyte leakage (EL), and malondialdehyde (MDA) production and Sb accumulation. Co-application of CMV and FMB increased biomass (29.50%) and grain yield (51.07%) of rice by increasing chlorophyll, and anthocyanin synthesis, leaf water contents, osmolyte synthesis, antioxidant activities, and decreasing production of H₂O₂, EL, and MDA and Sb accumulation in roots (90.41%) and shoots (96.38%). Furthermore, the combined addition of CMV and FMB also reduced the soil available Sb by 75.57% which resulted in less accumulation of Sb in plant parts and improved growth and yield. Given these facts, these findings indicate that co-application of CMV and FMB is a promising approach to remediate Sb-polluted soils and improve sustainable and safer rice productivity.

Continued drought during the late growth stage of super hybrid rice (SHR) markedly reduces yield, and management practices that use water more efficiently can contribute greatly to high and stable yields from SHR. The absolute temperature differences (ATDs) between the rice plant and the atmosphere and between the soil and the atmosphere are believed to be important determinants of grain yield. However, it has not previously been determined whether these ATDs have any effect on SHR yields under water-saving cultivation. A two-year field experiment involving two SHR varieties, Liangyoupeijiu (LYPJ) and Y-Liangyou 9000 (YLY900), evaluated the effects of reducing water supply from mid-booting to maturity on grain yield, canopy relative humidity (CRH), leaf area index (LAI), and ATDs between the ambient temperature and the leaf surface, panicles, canopy, and soil. Grain yield increased significantly under shallow water irrigation (SW), by 8.84% (YLY900) and 12.26% (LYPJ), but decreased significantly under mild water stress (MS, −20 to −30 kPa), by 14.36% (YLY900) and 9.47% (LYPJ), as well as severe water stress (SS, −40 to −50 kPa), by 35.06% (YLY900) and 28.74% (LYPJ). As water supply decreased, so did the CRH and the ATDs, with significant decreases under MS and SS. The temperature differences were significantly and positively correlated with grain yield (P < 0.01) in both cultivars. LAI was increased under SW conditions, but was significantly decreased under MS and SS. Our study suggests that the dual goal of saving water while maintaining high yield can be achieved by applying SW irrigation from mid-booting to maturity and by adopting cultivation measures that maintain high CRH and high plant–atmosphere and soil–atmosphere ATDs in order to alleviate water stress. YLY900 has a higher yield potential than LYPJ under SW conditions, suggesting that its wide cultivation may help achieve this dual goal.