胶州湾滨海湿地凋落物分解对土壤有机碳矿化的影响

通过室内培养试验和三维荧光光谱技术(3D-EEMs),开展了胶州湾滨海湿地碱蓬、芦苇和互花米草的分解对土壤有机碳矿化的影响研究。结果表明,凋落物的添加提高了土壤有机碳矿化速率和累积矿化量,具体表现为碱蓬互花米草芦苇空白对照;乘幂曲线模型能较好地描述有机碳矿化速率和累积矿化量的变化趋势。光谱分析表明,分解过程中类蛋白荧光强度始终大于类腐殖酸荧光强度;利用荧光区域积分进行定量分析表明,不同处理下类蛋白质物质占比最高,类腐殖质物质次之;荧光参数表明,土壤有机碳的芳香化程度在培养期间先升高后降低。凋落物分解通过增加土壤中的营养物质,提高了土壤中微生物活性,从而改变了土壤有机碳的结构和化学组分,且凋落物的植被特征决定了其对土壤有机碳矿化影响程度的大小。

Effect of litter decomposition on mineralization of soil organic carbon in the Jiaozhou Bay coastal wetlands

The effect of litter decomposition including Suaeda glauca, Phragmites australis, and Spartina alterniflora in Jiaozhou Bay coastal wetlands on the soil organic carbon mineralization was investigated using three-dimensional fluorescence spectroscopy (3D-EEMs) in laboratory. Addition of litters improved the mineralization rate and the cumulative mineralization of soil organic carbon, which decreased in the order of Suaeda glauca > Spartina alterniflora > Phragmites australis > control. The power curve model effectively described the trends of mineralization rate and the cumulative mineralization of soil organic carbon. Spectral analysis revealed that the fluorescence intensity of proteins was greater than that of humic acid during decomposition of litter. Fluorescence integration was performed for qualitative analysis, and the results showed that the proportion of aromatic protein substances was the highest, followed by the humic substances under different treatment conditions. Fluorescence parameters indicated that the degree of aromatization of soil organic carbon first increased and then decreased during the incubation period. Litter decomposition enhanced the soil microbial activity by increasing soil nutrients, which altered the structure and chemical composition of organic carbon in soil. In addition, the vegetation characters determined the degree of influence of litters on the soil organic carbon mineralization.