Long-term effects of biochar one-off application on soil physicochemical properties, salt concentration, nutrient availability, enzyme activity, and rice yield of highly saline-alkali paddy soils: based on a 6-year field experiment

A long-term (6-year), one-off application of biochar was conducted in a highly saline-alkali paddy field.Biochar consistently decreased soil BD, increased Tp, Ks, and improved soil aggregates.Biochar showed a sustained ability to alleviate saline-alkali stress.The continuous improvement of soil functions acted on the increase of rice yield.