Soil water stable isotopes, Evaporation loss, Infiltration, Soil water storage, Controlling factor, Physical geography, GB3-5030, Geology, QE1-996.5

Study region: Typical grain farmland (GF) and non-grain farmland (NGF) in the Eastern Loess Plateau (ECLP), China Study focus: We quantitatively evaluated the soil water infiltration, storage and evaporation capacity under typical grain farmland (GF) and non-grain farmland (NGF) in the ECLP during April-November 2023 based on time-series soil water stable isotopic data. New hydrological insights for the region: (1) Obviously temporal-spatial heterogeneity was observed in soil water δ18O of two farmland types, with the most dramatic fluctuations during the monsoon season. (2) Soil moisture under the NGF was more susceptible to precipitation infiltration than that of the GF. (3) Relatively larger soil water’s evaporation loss fraction (f) appeared in the period of S1 (before the monsoon season), and the f of the NGF was larger than that of the GF during the study period, especially in the 0–20 cm depth soil layer. (4) The soil water storage both under the NGF and GF displayed a gradually decreasing trend gradually and relatively larger soil water storage appeared in the NGF, especially in the 20–60 cm depth soil layer. (5) Soil water content (SWC) of the NGF was more sensitive to regional environmental factors variability than that of the GF. These findings hold considerable implications for optimizing regional water resource management and advancing agricultural sustainability.