不同有机物料投入下黄河故道土壤有机碳积累特征的研究

【目的】黄河故道潮土区土壤有机质含量低、结构差是限制当地作物优质高产的重要问题,通过连续施用不同有机物料,探究不同有机物料投入下,黄河故道区典型土壤的有机质积累特征,为该区土壤的快速固碳提供理论依据和参考方案。【方法】试验共设置7个处理：单施NPK肥作为对照(CK),其他处理在单施NPK肥的基础上增施有机肥6000 kg/hm_² (M1)、有机肥12000 kg/hm_² (M2)、树枝菌渣6000 kg/hm_² (B1)、树枝菌渣12000 kg/hm_² (B2)、秸秆菌渣6000 kg/hm_² (S1)、秸秆菌渣12000 kg/hm_² (S2), 采用随机区组设计。【结果】与CK相比,外源有机物料施入会显著增加玉米产量和有机质含量,增幅范围分别为21.7%～58.3%和37.4%～70.1%,产量的增加直接导致进入土壤的秸秆残渣及根茬碳相应增加38.9 kg/hm_²～76.9 kg/hm_²,致使 B2处理增产保肥效果最佳。就有机物料种类而言,用量为12000 kg/hm_²的树枝菌渣对土壤活性有机质的提升幅度最大,比相同用量的有机肥和秸秆菌渣高26.2%和57.0%,秸秆菌渣的碳库管理指数最高,但与树枝菌渣相比无显著差异。树枝菌渣由于碳氮比高,在土壤中分解慢,相同用量下,矿化消耗的碳量低于秸秆菌渣和有机肥,单位碳投入下的呼吸量比秸秆菌渣和有机肥低42.3%和29.3%。【结论】用量为12000 kg/hm_²的树枝菌渣由于碳投入量大,矿化消耗少,对黄河故道潮土有机质提升效果最好,玉米增产最明显。

Soil Organic Carbon Accumulation in Old Riverway of Yellow River Under Different Organic Material Inputs

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.