Soil moisture loss and movement between non-grain farmland and typical farmland on the Eastern Loess Plateau: Evidence from stable isotope

Typical grain farmland (GF) and non-grain farmland (NGF) in the Eastern Loess Plateau (ECLP), China 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. (1) Obviously temporal-spatial heterogeneity was observed in soil water δ 18 O 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. • Continuous daily soil water isotopic data of two farmland land types were monitored. • The soil water evaporation loss fraction in both farmland types is higher in Spring. • Stronger soil water storage capacity appeared in the grain farmland. • The soil water storage in non-grain farmland was more sensitive to environmental factors.