Abstract: The decline of soil quality in tidal flat is one of the main reasons for the degradation of Suaeda heteroptera wetland in Liaohe estuarine. Application of soil amendments can effectively improve soil quality. We explored the effects of improved biochar, humus soil, organic fertilizer, rice straw and bio-bacterial fertilizer on soil physicochemical properties and the growth of S. heteroptera in Panjin red beach where S. heteroptera has disappeared for many years. The results showed that soil salt content, bulk density, and <0.25 mm aggregates decreased after the applications of amendments, which were significantly negatively correlated with root length, plant height, plant density, and biomass of S. heteroptera (P<0.05). Soil porosity, >0.25 mm aggregates, and the concentrations of organic matter, alkali-hydrolyzed nitrogen, available phosphorus and potassium increased, which were significantly positively correlated with root length, plant height, plant density and biomass of S. heteroptera except organic matter (P<0.05). The application of organic fertilizer and bio-bacterial fertilizer had stronger improvement effect on soil in tidal flat, followed by humus soil. This study provides theoretical basis and technical support for exploring lowcost methods of soil improvement in S. heteroptera wetland.

Key words: amendment,  Suaeda heteroptera wetland, soil in tidal flat, degradation.