Soil water response to extreme drought-rewetting events under typical land use patterns in a rainfed farmland system

The loess tableland region, China. A decade-long (2014–2023) investigation assessed soil water content (SWC) dynamics across four rainfed farmlands (Alfalfa field, AF; Fertilized cropland, FC; Unfertilized cropland, UC; Fallow field, FF) to clarify post-drought soil water replenishment. Using the Standardized Precipitation Index (SPI), three extreme drought-rewetting events (WE1: 93.6 mm, WE2: 47.4 mm, WE3: 131.2 mm) representing precipitation gradients were identified. New hydrological insights for the region: Soil water response varied significantly with land use and rainfall intensity. Recharge depths differed notably: during WE1, the depths reached 100 cm for AF, FF, and UC, but only 50 cm for FC, with corresponding ∆SWC increments of 5.3%, 6.4%, 8.1%, and 3.7%, respectively. In WE2, the depths for AF, FF, and UC reached 120 cm versus FC's 100 cm. During WE3, FF achieved 260 cm, while AF and FC remained at 100 cm. Precipitation storage efficiency (PSE) peaked in FF (WE1, 48.2%) and AF (WE2, 80.9%; WE3, 56.3%), showing a nonlinear relationship with precipitation linked to antecedent soil water content (ASWC). Daily precipitation and duration governed wetting duration and front uniformity; FC exhibited the longest duration (12 days) under low-intensity, long-duration rainfall. These findings elucidate soil water dynamics during extreme climate events, aiding disaster forecasting in rain-fed agricultural regions. This figure illustrates that the specific responses of soil water replenishment to rainfall events following extreme drought, among them, figure (A) explains the soil water content (SWC) before and after wetting events in different land use types. In this figure, (a), (b) and (c) present WE1, WE2 and WE3, respectively. ∆SWS refers to the accumulation of soil water storage during the wetting event. AFb, AFa, FFb, FFa, FCb, FCa, UCb and UCa represent the soil water content before and after the wetting events in alfalfa field, fallow field, fertilized cropland, and unfertilized cropland, respectively. Figure (B) shows PSE after wetting events under different land use types, and figure (C) represents soil wetting events in rainfall events of wetting events under different land use types. Where different shades of color represent different shapes represent the degree of soil water variation. • A 10-year observation uncovers land use reshapes post-drought rewetting patterns. • Long-term unfertilization enhanced the precipitation storage efficiency of rainfed farmland. • The decrease of daily rainfall caused the wetting front to slow down during drought rewetting events.