The low organic matter content and poor structure of tidal soil are the main factors limiting the high quality and high yield of crops in the old riverway of the Yellow River. In this study, through the continuous application of different kinds and amounts of organic materials in field plot experiment with randomized block design, the accumulation of soil organic matter was studied to provide theoretical basis and reference for rapid carbon sequestration in the study area. Seven treatments were designed, including:1) CK, NPK fertilizers used; 2) M1, CK + 6 000 kg/hm² organic fertilizer; 3) M2, CK + 12 000 kg/hm² organic fertilizer; 4) B1, CK + 6 000 kg/hm² dendritic residue; 5) B2, CK + 12 000 kg/hm² dendritic residue; 6) S1, CK + 6 000 kg/hm² straw slag; 7) S2, CK + 12 000 kg/hm² straw slag, three repeat for each treatment. The results showed that, compared with CK, organic material input significantly increased corn yield and soil organic matter content by 21.75%-58.32% and 37.4%-70.1%, respectively. The yield increase directly led carbon increase from straw residues and roots into soil by 38.9-76.9 kg/hm², among of which, B2 treatment had the best effect. For organic material types, B2 treatment increased soil active organic matter most, which was 26.2% and 57.0% higher than that of M2 and S2 treatments, respectively. Meanwhile, S treatments had the highest C pool management index, but not significantly different to B treatments. Due to the high C/N ratio, dendritic slag is slowly decomposed in soil, the amount of carbon consumed by the mineralization is lower than those of straw residue and organic fertilizer, and the respiration rate per unit carbon input was 42.3% and 29.3% lower than those of straw residue and organic fertilizer. In conclusion, 12 000 kg/hm² dendritic slag has the largest carbon input, less mineralization consumption and best effects in promoting organic matter content of the tidal soil in the old riverway of the Yellow River and in increasing corn yield.