Response and resilience of farmland ecosystems to flash drought in China

• Heatwave flash droughts are more likely in rainfed cropland. • Precipitation deficit flash droughts are more common in irrigated cropland. • Net Primary Productivity is more sensitive to precipitation deficit flash droughts, particularly in irrigated areas. • Rainfed cropland shows greater resilience compared to irrigated cropland. Flash droughts negatively impact agricultural ecosystems and threaten food security due to their rapid development and unpredictability. This study utilized reanalyzed data from 2000 to 2018 and employed a comprehensive index method to identify two flash droughts: heat wave flash droughts (HWFD) and precipitation deficit flash droughts (PDFD). We analyzed the spatiotemporal evolution of these droughts across China’s farmland ecosystems and investigated the response patterns of these ecosystems to both types of flash droughts using response frequency and response time metrics. Our findings indicate that between 2000 and 2018, flash droughts were most frequent in June, with the highest frequency and most extended duration occurring in summer and the lowest in autumn. Spatially, HWFD frequency was highest in the Loess Plateau, with durations of 4.4 and 5.0 octads, while PDFD was most frequent in the Gansu-Xinjiang (GX) and Huang-Huai-Hai (HHH) regions. Over time, there was a decrease in the frequency and duration of flash droughts. The study revealed that Net Primary Productivity (NPP) generally exhibited a low response frequency to flash droughts, with PDFD showing a higher response frequency and a shorter response time than HWFD. Irrigated farmland showed higher NPP response frequencies, particularly in the HHH region, whereas rainfed farmland demonstrated stronger resilience to flash droughts. This research provides theoretical support for developing flash drought early warning systems and drought mitigation policies, significantly contributing to food security in China’s farmland ecosystems.