Soil nitrogen mineralization (N_min) is a key process that converts organic N into mineral N that controls soil N availability to plants. However, regional assessments of soil N_min in cropland and its affecting factors are lacking, especially in relation to variation in elevation. In this study, a 4-week incubation experiment was implemented to measure net soil N_min rate, gross nitrification (Nit) rate and corresponding soil abiotic properties in five field soils (A–C, maize; D, flue-cured tobacco; and E, vegetables; with elevation decreasing from A to E) from different altitudes in a typical intensive agricultural area in Dali City, Yunnan Province, China. The results showed that soil N_min rate ranged from 0.10 to 0.17 mg·kg⁻¹·d⁻¹ N, with the highest value observed in field E, followed by fields D, C, B, and A, which indicated that soil N_min and Nit rates varied between fields, decreasing with elevation. The soil Nit rate ranged from 434.2 to 827.1 µg·kg⁻¹·h⁻¹ N, with the highest value determined in field D, followed by those in fields E, C, B, and A. The rates of soil N_min and Nit were positively correlated with several key soil parameters, including total soil N, dissolved organic carbon and dissolved inorganic N across all fields, which indicated that soil variables regulated soil N_min and Nit in cropland fields. In addition, a strong positive relationship was observed between soil N_min and Nit. These findings provide a greater understanding of the response of soil N_min among cropland fields related to spatial variation. It is suggested that the soil N_min from cropland should be considered in the evaluation of the N transformations at the regional scale.