On average, GluN accounts for about 60% of the total AS in soils, followed by GalN (30%), MurN acid (7%), and ManN (4%) [10]. Muramic acid and glucosamine are primarily derived from bacteria and fungi, respectively, and their accumulation correlates with metabolic activities and microbial growth [10; 11]. Galactosamine is derived from bacteria [12], but other authors assume that it is derived from fungi [13]. Ratios of AS can be used to quantify the accumulation of bacterial and fungal residues in soils [2]. The ratio of glucosamine to galactosamine is used to determine the contribution of fungi to SOM stability, while the ratio of glucosamine to muramic acid is used to determine the contribution of bacteria to AS accumulation [3; 14]. Inorganic N enrichment influences the retention of microbial residues and regulates key processes in SOC turnover [15]. Microbial residues are the main carbon resource for persistent soil carbon pool, accounting for about 50% of SOC [16]. The balance between the synthesis and decomposition of microbial metabolites is directly related to the accumulation of microbial residues in the soil [10]. The amount of microbial residue C in SOC is used to quantify the contribution of microbe-derived carbon to SOC [16]. Microbial residues serve as an important source of stable carbon; thus, its contribution to SOC pool variations will influence predictions of global change on SOC pools. Therefore, studying the accumulation of microbial residues in soils is important in understanding the influence of microbes on SOC stabilization and the global C cycle [17]. Moreover, N enrichment leads to a shift from fungi to bacteria-dominated microbial communities [18]; this affects the ratio of fungal to bacterial residues, which in turn affects AS accumulation in soils. Nitrogen enrichment has also been reported to reduce microbial residues and amino sugar accumulation in N-limited acidic soils as a result of soil acidification or N saturation [19; 20]. Soils with low pH (acidic soils) suppress microbial activities and growth [21; 22; 23], which negatively affects microbial residues and amino sugar accumulation. Soil pH is an important factor regulating the degradation of microbial cell walls, with a low pH favoring the degradation of chitin, while a high pH stimulates the degradation of peptidoglycan [5]. The response of microbial residues and amino sugar accumulation to inorganic N enrichment in acidic soils has been extensively studied [24; 25]. Nevertheless, the effects of chronic N enrichment on microbial residues and amino sugar found in alkaline soils are poorly understood. We hypothesized that chronic N enrichment would promote microbial growth and activity as well as improve the biochemical properties of the alkaline soil, which in turn would stimulate microbial residues and AS accumulation over time. Adequate N enrichment enhances the ability of soil microbes to sequester N or C into their residues, which consequently increases net microbial AS accumulation over time [26]. Hence, it is important to investigate how different chronic N enrichment rates affect carbon and nitrogen sequestration in agricultural alkaline soils in order to understand the contribution of microbial residues and amino sugars to SOM stability. The study was therefore conducted to determine the effects of chronic N enrichment on microbial residues, amino sugar concentrations, and biochemical properties of an alkaline loess soil.