Abstract:【Objective】It is of great scientific significance to explore effects of the practice of subsoiling coupled with fertilization on the fractions of activated organic carbon and nitrogen, and enzyme activities in black soil. 【Method】Based on a 2-year field experiment in Qinggang County, Heilongjiang Province, a black soil region typical of Northeast China, variations of the soil were analyzed in fractions of dissolved organic carbon (DOC), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), particulate organic carbon (POC), particulate organic nitrogen (PON), and readily oxidizable organic carbon (ROC), and in activity of N-acetylglucosaminnidase (NAG), Cellobiohydrolase (CBH), β-glucosidase (BG) and β-xylosidase (BXYL) with treatment in the experiment, which consisted of five treatments, including no-till + chemical fertilizer (T1), subsoiling 25 cm (in depth) + chemical fertilizer (T2), subsoiling 25 cm + chemical fertilizer + organic manure (T3), subsoiling 35 cm + chemical fertilizer (T4), sub-soiling 35 cm + chemical fertilizer+ organic manure (T5) .【Result】Results showed that both subsoiling and fertilization and their interactions significantly affected the contents of soil activated carbon and nitrogen, particularly of POC and PON; Subsoiling (T2 and T4) significantly reduced the contents of soil activated organic carbon and nitrogen components with varying degree relative to depth of subsoiling, T2 was significantly lower than T1 (P<0.05) in POC and PON content; T3 and T5 significantly increased the contents of soil activated organic carbon and nitrogen. T3 was 8.37%, 46.64%, 35.10% and 42.39% (P<0.05) higher than T2 in content of SOC, POC, ROC and PON. Besides, subsoiling improved stability of the soil activated organic carbon and nitrogen components. Compared with T1, subsoiling treatments significantly reduced the ratios of MBC/SOC and POC/SOC in the soil (P<0.05), and subsoiling 35 cm in depth significantly decreased the ratio of PON/TN (P<0.05); T2 and T4 did not differed much from T1 in enzyme activity, whereas T3 significantly increased CBH activity relative to T2. 【Conclusion】To sum up, subsoiling 25 cm in depth combined with application of chemical fertilizer and organic manure can maintain the content of activated organic carbon and nitrogen components in the soil, hence it is recommended to be extrapolate as an effective farming technique to build up black soil farmland and to increase organic matter content in the soil of this area.