Soil physicochemical properties and enzyme activity data under nickel–cobalt–manganese (NCM) contamination

This dataset contains soil physicochemical properties (pH and electrical conductivity) and enzyme activity measurements obtained from a controlled incubation experiment assessing the effects of nickel–cobalt–manganese (NCM) contamination on two agricultural soils with contrasting properties (Anshida and Tongling, China). Soils were amended with NCM at six concentration levels (0, 100, 200, 300, 400, and 500 mg·kg⁻¹ dry soil), with three independent replicates per treatment (n = 3). The dataset includes raw replicate measurements, processed mean values, and statistical outputs (one-way ANOVA and Duncan’s multiple range test), as well as normalized enzyme activity data (0–100) used for radar plot visualization. Enzyme activities include catalase, sucrase, acid phosphatase, urease, and amylase. Normalization was performed independently for each soil using min–max scaling to facilitate relative comparisons among enzymes and treatments. These data support the analyses and figures presented in the associated manuscript examining soil biochemical responses and functional plasticity under mixed-metal stress.