Biochar increases rice yield by improving root morphological and root physiological functions in heavily saline-sodic paddy soil of Northeast China

Saline-sodic soil is one of the major threats to crop growth, production, and quality. Biochar amendment could alleviate the adverse impacts of saline-sodic stress in crops. However, the effect of biochar on root morphological, root physiological functions, and rice yield in saline-sodic paddy soil has not been studied. Here, the underlying mechanisms of positive effects in morphological characteristics and physiological functions of rice roots under heavily saline-sodic paddy soil amended with biochar were evaluated. The soil was amended with biochar at zero-biochar (CK), 15g kg-1 soil (T1), 30 g kg-1 soil (T2), or 45 g kg-1 soil (T3). Biochar addition significantly increased root length, root volume, root dry weight, and root-shoot ratio at all growth stages. The root absorption vigor and root oxidization capacity were enhanced and increased significantly by decreasing Na+/K+ ratio, MDA content, and increasing K+ concentration in rice root after biochar amendment. The root bleeding rate of biochar treatments at different growth stage were 11.01% to 67.73% greater than these of CK. The yield of rice was increased significantly under saline-sodic paddy soil after biochar amendment. It was concluded that biochar had positive effect on the morphological characteristics and physiological functions in rice roots in saline-sodic paddy soil.