氮肥配施生物质碳点对潮土微生物残体碳含量的影响

    Effects of Nitrogen Fertilizer Combined with Biomass Carbon Dots on Contents of Microbial Necromass Carbon in Fluvo-aquic Soils

    • 摘要: 为探明碳氮投入下土壤微生物残体对有机碳积累的相对贡献, 采用培养试验方法探究氮肥配施生物质碳点(简称碳点)对潮土微生物残体碳含量的影响。研究设置4个处理: 空白(CK)、施碳点(CDs)、施氮(N)、施氮和碳点(N+CDs)。结果表明: 与CK处理相比, CDs处理的无机氮(SIN)含量显著下降29.1%;与N处理比较, N+CDs处理的SIN含量显著下降32.8%, 土壤脲酶和亚硝酸还原酶活性均显著下降(P < 0.05)。CDs处理的土壤溶解性有机碳(DOC)含量略高于CK处理, 且CDs处理改变了DOC的官能团结构; N+CDs处理的DOC含量比N处理显著提高28.8%, N+CDs也提高了DOC中胺类和芳香类化合物含量。与N处理比较, N+CDs处理的细菌残体碳(BNC)和真菌残体碳(FNC)含量显著增加29.5%和17.7%(P < 0.05), 且提高了土壤微生物残体对有机碳积累的相对贡献。回归分析表明, 总的细菌和真菌残体碳与土壤理化性质存在相关性。通过结构方程模型进一步验证, 发现DOC中的芳香族化合物是调控BNC的主要因素, FNC主要受土壤氮净硝化速率和DOC的平均分子量调控, N+CDs处理主要通过改变潮土溶解性有机碳及官能团结构和氮转化速率影响微生物残体碳积累。

       

      Abstract: To elucidate the contribution of soil microbial necromass to organic carbon accumulation under carbon and nitrogen inputs, this study used a microcosm experiment to explore the effect of nitrogen fertilizer combined with carbon dots on the content of microbial necromass carbon in fluvo-aquic soils. Carbon dots (CDs) is one of the nano-carbon materials deriving from organic waste matters of salvia miltiorrhiza. Four treatments were set up: control, neither N nor CDs addition (CK), CDs amendment (CDs, w=0.15%), N fertilizer addition (N, urea), N fertilizer and CDs amendment (N+CDs). Each treatment had three replicates for incubation period. The results show that compared to CK treatment, the content of inorganic nitrogen (SIN) under CDs treatment significantly decreased by 29.1% (P < 0.05). Compared with N treatment, the SIN content of N+CDs treatment significantly decreased by 32.8%, simultaneously, soil urease and nitrite reductase activities also decreased. The soil dissolved organic carbon (DOC) contents not only increased in CDs treatments, but also the functional group structure of DOC was altered by CDs treatment compared to CK treatment. Compared to N treatment, the content of DOC significantly increased by 28.8% under N+CDs. It also increased the contents of amines and aromatic compounds in DOC. Compared with N treatment, the contents of bacterial necromass carbon (BNC) and fungal necromass carbon (FNC) in N+CDs treatment significantly increased by 29.5% and 17.7% (P < 0.05), respectively. Meanwhile, they also increased the relative contribution of the accumulation of organic carbon from soil microbial necromass. Regression analysis revealed a correlation between total bacterial and fungal necromass carbon and soil physicochemical properties. Further analysis through establishing structural equation modeling reveals that aromatic compounds in DOC were the main factors to regulate BNC, while FNC was primarily regulated by the net nitrification rate and the average molecular weight of DOC. In this study, nitrogen fertilization combined with CDs had primarily driven microbial necromass carbon accumulation by altering the functional group structure of dissolved organic carbon and inorganic nitrogen content.

       

    /

    返回文章
    返回