Quantifying the food-water nexus and key drivers in China's agricultural sector

China faces major challenges of balancing food security and water resources conservation. However, little is known about the space-time interactions of food production and water consumption. To fill in this knowledge gap, this study quantitatively analyzed China's spatial-temporal dynamics in crop production and irrigation water demand (IWD), and decomposed their driving factors using the method of Logarithmic Mean Divisia Index. The results indicated that China's national IWD and crop production had strong space-time correlations over the past decades, and their gravity centers gradually concentrated towards the arid northern regions. These spatial shifts exacerbated the unbalance of water resources and crop production between north and south. Among all the driving factors, planted area contributed the most to the increase in IWD (+88%), followed by irrigation water demand per unit area (+18%) and crop mix (−6%). In particular, the expansion of planted area in water-scarce regions intensified the food-water nexus and aggravated China's water scarcity. Fortunately, this research found that rational optimization of cropping systems could largely mitigate agricultural water consumption without sacrificing food production. These findings provide valuable insights for reducing trade-offs and enhancing synergies between food security and water sustainability.