Soil salinization of grassland seriouly affects the development of regional animal husbandry. It is urgent to improve the salinized land to enhance its quality and ensure the ecological security of grassland production. In this study， cattle manure （NF） was utilized as raw material to produce biochar through carbonization at different temperatures （400℃， NF4； 500℃， NF5）， with corresponding Ca（NO₃）₂-modified counterparts （Ca4， Ca5）. These amendments were systematically evaluated for their remediation effects on saline-alkali grassland soils， to provide data and technical support for sustainable manure valorization and salinized soil improvement. Biochar and its modified counterparts amendments significantly reduced both soil pH and total alkalinity （P<0.05）， with NF4 showing the greatest pH decrease and NF5 exhibiting the maximum alkalinity reduction. Soluble sodium content was significantly reduced （P<0.05）， with NF4 and Ca4 showing the highest reductions. Biochar amendments also significantly increased soil organic carbon （P<0.05）， available phosphorus， and exchangeable potassium， with carbonized manure demonstrating the greatest improvements. Overall， NF4 optimally balanced alkalinity reduction and nutrient enhancement， suggesting its priority for saline-alkali soil remediation when using cattle manure to improve saline soil.

Saline soil  /  Carbonized manure  /  Manure modification  /  Soil alkalinity  /  Soil nutrients