Response of Different Agricultural Ecosystems to Different Drought Stages in Central Asia

ABSTRACT Central Asia (CA), as a typical arid region, frequently experiences drought events, including both regular and flash droughts. However, the differential impacts of these drought stages on agricultural ecosystems with varying water sources have not been sufficiently explored. This study utilised soil moisture data from the Global Land Data Assimilation System (GLDAS), treating flash droughts as a sub‐phase of regular droughts, to identify both regular and flash droughts in CA from 1948 to 2022 and examined the responses of agricultural ecosystems with different water sources from 1982 to 2022. The results indicated that: (1) Regular droughts occurred most frequently in rainfed agricultural areas in central and southeastern CA, exceeding 50 pentads (5 days). In contrast, flash droughts were more prevalent in irrigated agricultural areas in central, southeastern and northern CA, lasting 2–5 pentads. (2) There existed a significant causal relationship between standardised normalised difference vegetation index (NDVI Z ) and soil moisture index (SSMI) across various croplands, with a lag time of 9–12 months. Both NDVI Z and SSMI decreased with increasing drought duration, with more rapid declines observed during flash droughts. (3) Rainfed agriculture was highly sensitive to soil moisture changes with a more pronounced negative relationship, whilst irrigated agriculture reduced this negative correlation and tended to a positive correlation by improving water use efficiency. This highlights the crucial role of water resource optimisation and drought management in enhancing agricultural resilience and sustainability, providing important scientific evidence for addressing water shortages under future climate change.

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