Water-saving irrigation is widely adopted in arid and semi-arid regions to enhance agricultural water efficiency, yet its ecological impacts on farmland shelterbelts (FSBs) remain unclear. This study integrates multi-source remote sensing and hydrological modeling to assess FSB security in Zhangye City, Northwest China. A Random Forest classifier was applied to Sentinel-1/2 time-series data (2017–2023) to map FSB distribution and quantify coverage change, while GF-2 imagery provided NDVI time series (2015–2024) to evaluate vegetation vitality. Soil moisture dynamics under drip irrigation were simulated using HYDRUS-2D; soil hydraulic parameters were calibrated using in-situ soil moisture observations from the 2017 drip irrigation season (excluding August) and independently validated with observations from the August 2017 irrigation period. Results show that FSB area declined by 38.9 % from 2017 to 2023, and NDVI in drip-irrigated FSBs was 58 % lower than in flood-irrigated counterparts, indicating chronic water stress. However, during the extreme aridity of 2023, drip-irrigated FSBs exhibited 70 % higher drought resilience. Projections suggest a continued annual loss of 1.253 ± 0.30 km² yr - ¹ until completion of high-standard farmland transformation. Simulations and field observations indicate a 43.75 % reduction in root-zone moisture (40–160 cm), limiting lateral water diffusion and shifting FSB water supply toward groundwater dependence, thereby undermining long-term sustainability. These findings highlight the need to incorporate ecological water requirements into irrigation modernization and to develop targeted farmland shelterbelts restoration strategies. • Integrating remote sensing and HYDRUS-2D reveal degradation mechanisms of farmland shelterbelts. • FSB area is declined, ∼1.25 km2 yr-1, by widely applications of saved-water techniques in semi-arid regions. • NDVI in drip-irrigated FSBs was 58 % lower than in flood-irrigated zones. • Drip irrigation reduced root-zone soil moisture (40–160 cm) by 43.75 %. • Hydrological disconnection forces FSBs to rely solely on deep groundwater.
Zhang et al. (Sat,) studied this question.