The Atacama Desert hosts the driest regions on Earth, so agriculture relies entirely on artificial irrigation. This study examined how cultivation under hyperarid conditions alters soil chemical properties, focusing on total carbon (TC), organic and inorganic carbon fractions, total nitrogen (TN), delta 13C and delta 15N signatures, and soil texture. Samples were collected at 0-15 and 15-30 cm depths from four agricultural sites irrigated with different water sources (groundwater, river water, freshwater, wastewater, and fog-water) and compared with uncultivated controls. Differences between cultivated and control soils occurred, but responses were not uniform. Some sites showed minor changes, whereas others displayed strong but contrasting patterns. The greatest enrichments of TC and TN occurred in freshwater-and wastewater-irrigated plots, while river-and fog-water sites showed weaker and more variable responses. These patterns reflect interacting effects of irrigation source, management, soil texture, and geogenic background conditions. TC closely followed organic carbon, indicating that variation in TC mainly reflects changes in the organic fraction. In contrast, inorganic carbon largely mirrors geogenic carbonate inputs that can obscure management effects. In topsoil, TC stocks reached 1217 dt ha-1 and TN stocks 93.33 dt ha-1, providing the first quantitative estimates for agricultural soils in the hyperarid Atacama Desert.