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This study quantified soil organic carbon (SOC) and soil total nitrogen (STN) changes in three long-term (14 years) experiments comparing conventional tillage (CT) and different no-till (NT) cropping systems using a diachronic approach and an equivalent soil mass approach. The three experiments were established in 2009 in a randomized complete block design with three replicates and comprise maize (MaiEx)-, soybean (SoyEx)-, and cassava (CasEx)-based cropping systems. Soil samples were collected in 2021, 10 years after the first sampling (2011), at 7 depths: 0–5, 5–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. At 0–10 cm depth, NTs significantly increased SOC stock at a rate of 0.35, 0.51 and 0.73 Mg C ha-1 y-1 for CasEx, SoyEx and MaiEx, respectively. CT exhibited a positive trend only on CasEx with an accumulation rate of 0.14 Mg C ha-1 y-1 (0-10 cm). A significant SOC accumulation was observed under NT cropping systems for CasEX and MaiEx up to 60-80 and 80-100 cm depth, respectively. By contrast, STN stock significantly increased under NT cropping systems only at 0–5 cm depth with an accumulation rate of 13.9, 22.9 and 34.0 kg N ha-1 y-1 under CasEx, SoyEx and MaiEx, respectively. A depletion of N stocks was observed under CT and NT cropping systems at deeper soil layers. Over 10 years of time, SOC accumulation rate of NT, at 0-100 cm depth, reached 1.08 and 1.73 Mg C ha-1 yr-1 for CasEx and MaiEx, respectively while non-significant change was observed under NT SoyEx and CT of the three experiments. The findings suggest that long-term NT cropping systems with high amount of biomass-C inputs and crop rotation enhance SOC sequestration even at deeper soil layers. However, these results raise questions about the dynamics of N under NT cropping systems.