Biochar-based metal oxide nanocomposites (BNCs) are the new classes of soil amendment materials, which combine the benefits of biochar with nano-materials. This research was conducted to evaluate the possible effects of biochar-based nanocomposites (25 g biochar kg⁻¹ soil; 25 g BNC-MgO kg⁻¹ soil; 25 g BNC-MnO kg⁻¹ soil and 12.5 g BNC-MgO + 12.5 g BNC-MnO kg⁻¹ soil) on phenology, morphology and productivity of safflower plants (Carthamus tinctorius L.) under salt stress (non-saline, 6 and 12 dSm⁻¹ NaCl salinities). Soil had a silty loam texture with low organic matter, neutral pH and 18.80 cmol kg⁻¹ cation exchange capacity. Application of biochar and particularly BNCs increased the pH and cation exchange capacity of soil, growth of main and lateral roots (especially lateral roots), root density, plant height, shoot diameter, leaf area, chlorophyll content and stability, branches and flowers per plant, potassium, magnesium and manganese contents, duration of reproductive stage, plant biomass, seed and oil yields of safflower under salt stress. The sodium content and duration of vegetative stage in safflower plants were reduced by biochar and BNCs treatments. In general, BNC-MgO in individual and combined forms with BNC-MnO were the superior treatments for enhancing safflower root and shoot growth and productivity under salt stress through improving the phenological (reproductive stage) and morphological parameters of plants.

生物炭基金属氧化物纳米复合材料 (BNCs) 是新型土壤改良材料，它结合了生物炭和纳米材料的优点。本研究旨在评估基于生物炭的纳米复合材料（25 g biochar kg ^-1土壤；25 g BNC-MgO kg ^-1土壤；25 g BNC-MnO kg ^-1土壤和 12.5 g BNC-MgO + 12.5 g BNC-MnO kg ^-1土壤）对盐胁迫（非盐分、6 和 12 dSm ^-1 NaCl 盐度）下红花植物（Carthamus tinctorius L.）的物候、形态和生产力的影响。土壤为粉质壤土质地，有机质含量低，pH 值为中性，18.80 cmol kg ^-1阳离子交换能力。生物炭特别是 BNCs 的应用增加了土壤的 pH 值和阳离子交换能力、主根和侧根（尤其是侧根）的生长、根密度、株高、枝条直径、叶面积、叶绿素含量和稳定性、每株分枝和花朵，钾，镁和锰含量，繁殖期持续时间，植物生物量，盐胁迫下红花的种子和油产量。生物炭和BNCs处理降低了红花植物营养阶段的钠含量和持续时间。一般来说，BNC-MgO 与 BNC-MnO 的单独和组合形式是通过改善植物的物候（繁殖阶段）和形态参数来提高盐胁迫下红花根和芽生长和生产力的优良处理方法。