Soil ecosystem services (SES) provide multiple benefits to humans. However, there is no current consensus regarding SES valuation models or a comprehensive framework to facilitate economic and other valuations. Several factors such as soil natural capital, soil properties, and supporting soil function in dynamic relations underlie the SES. Soil water storage (SWS) and soil fertility are significant determinants of SES. This study assessed the economic value of SES related to SWS and soil fertility in Khon Kaen Province, northeast Thailand. We compared SES across different land uses, including native forests and agricultural fields cultivated with cassava and sugarcane. Soil field capacity was assessed using hydraulic parameters derived from the soil water retention curve (SWRC). Field capacity (θ_FC) was then used to estimate available water capacity (θ_AWC). Soil fertility was evaluated by analyzing organic matter content and levels of nitrogen, potassium, and phosphorus. Results showed that forests were superior in both SWS and soil fertility. Using a market price approach, the economic value of SWS was highest in forests (5,912 baht/hectare), followed by cassava fields (5,426 baht/hectare) and sugarcane fields (4,843 baht/hectare). Soil fertility value was also highest in forests (470,346.3 baht/hectare), followed by sugarcane fields (117,754.2 baht/hectare), and cassava fields (93,205.65 baht/hectare). SWS and soil fertility were closely related, with higher SWS potentially improving fertility. The significant costs associated with maintaining soil fertility should be reflected in SWS valuations. These findings provide a starting point for improving land quality, particularly for future agricultural use.