Abstract: Soil enzyme activity is a fundamental biochemical indicator that reflects microbial metabolic functioning and the intensity of nutrient cycling processes within soil ecosystems. Understanding how soil enzyme activity, enzymatic stoichiometry, and microbial nutrient limitation respond to land-use change is essential for developing effective soil management strategies, particularly in the black soil region of Northeast China, where maintaining soil fertility and ecological stability is of critical importance. In this study, a total of 78 soil samples were collected from representative farmland and forest sites using a systematic grid sampling design to ensure comprehensive spatial coverage. The activities of β-1,4-glucosidase (BG), β-N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (AP) were quantified, and their stoichiometric characteristics were analyzed to assess microbial nutrient-acquisition strategies. Redundancy analysis was further conducted to explore the interactive relationships among enzyme activities, microbial nutrient limitation, soil physicochemical properties, and climatic variables. The results showed that forest soils exhibited significantly higher activities of BG, NAG, LAP, and AP compared with farmland soils. Specifically, the activities of BG, NAG, LAP, and AP increased by 74.35% (P<0.05), 108.70% (P<0.01), 80.12% (P<0.05), and 31.87% (P<0.05), respectively, indicating that forest ecosystems generally support more active microbial metabolism and stronger nutrient cycling potentials. Redundancy analysis demonstrated that soil pH was the most important factor explaining the spatial variation in enzyme activities, with an explanatory power of R²=0.74. Mean annual precipitation and ammonium-nitrogen content were also influential, accounting for 31% (R²=0.31) and 30% (R²=0.30) of the total variation, respectively. The enzymatic stoichiometric ratio associated with microbial acquisition of carbon, nitrogen, and phosphorus was 1∶1.34∶1.58, indicating disproportionate microbial investment toward nitrogen- and especially phosphorus-acquiring enzymes. Both farmland and forest soils exhibited clear microbial phosphorus limitation, while the limitation was more pronounced in farmland soils. This stronger phosphorus limitation in farmland likely results from long-term tillage intensity and unbalanced fertilization practices, which cause relative enrichment of carbon and nitrogen, alter microbial community structure, reduce soil phosphorus availability, and constrain microbial functional potential. Soil pH, mean annual precipitation, and ammonium-nitrogen content were identified as the key environmental drivers regulating soil enzyme activity at the regional scale. Overall, the findings suggest that ecologically informed soil management strategies, including rational phosphorus fertilization, optimized water management, and reduced soil disturbance, are essential for alleviating microbial phosphorus limitation, enhancing soil nutrient cycling efficiency, and promoting long-term ecological sustainability in the black soil region of Northeast China.