Effects of reed biochar on the oil sunflower (<i>Helianthus annuus</i> L.) growth in a saline-alkali soil

Soil salinization in the coastal wetlands of the Yellow River Delta severely restricts regional ecological security and agricultural development. Biochar technology, widely recognized for its dual advantages in carbon sequestration and soil amelioration, has been extensively promoted as a novel approach for remediating coastal saline-alkali soils. Although biochar can be produced from a variety of raw materials, research on its synthesis using halophytic plants remains limited. Guided by circular economy principles, the conversion of reed, a representative halophyte in this region, into biochar achieves dual objectives: efficient utilization of saline-tolerant vegetation and implementation of a "saline-derived, saline-applied" model, which holds significant practical value for advancing circular ecological development. In this study, reed straw biomass was used to prepare biochar at pyrolysis temperatures of 450°C (RBC450) and 600°C (RBC600). A pot experiment was conducted to investigate their effects on the growth of oil sunflower (Helianthus annuus L.) in saline-alkali soil. Results demonstrated that RBC450 significantly increased plant height by 173.7% and aboveground biomass by 92.5%, while RBC600 enhanced plant height by 107.7%. In contrast, raw reed biomass exhibited no statistically significant improvement. This research provides both a theoretical foundation and technical insights for the resource-oriented remediation of coastal saline soils and the high-value utilization of halophytic vegetation.