Groundwater depletion in China's Granary: The unintended consequences of cropping pattern shifts

Groundwater storage (GWS) depletion poses a growing concern for Northeast China (NEC), one of the nation's major grain-producing regions, with significant implications for regional food security. Understanding the spatiotemporal dynamics of this decline and identifying its primary drivers are critical for sustainable water management. While climatic factors such as rainfall are well-documented drivers, the role of human-induced factors, particularly increased irrigation driven by cropping pattern shifts (CPS), remains underexplored. Using trend analysis, counterfactual scenario analysis, and partial least squares-structural equation modeling (PLS-SEM), this study reveals a statistically significant GWS decline of 0.40 cm/yr from 2002 to 2023. This decline is primarily driven by the conversion of upland crops like soybean to water-intensive corn and paddy rice, as these shifts have increased irrigation water demand by 1.19 × 10⁹ m³/yr. The PLS-SEM analysis further confirms a significant causal link between CPS and GWS reduction (Total Effects = -0.31), highlighting the pivotal impact of expanding water-intensive crops. These findings call for integrated strategies to balance food security with groundwater sustainability, advancing synergies between Sustainable Development Goals 2 and 6.