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Drought seriously endangers the development of agro‐pastoral ecotone in arid and semi‐arid regions. However, drought evolution characteristics of semi‐arid sandy grassland and its drivers are not well understood in the complex climate change context. Thus, in this paper, the revised standardized precipitation evaporation indices on one‐month (SPEI‐1) and growing‐season (SPEI‐6) scale, flash drought and dry spells (DS) were calculated as drought indicators, and the temporal variabilities and meteorological drivers of drought in Horqin Sandy Land during the growing period (April–September) from 2007 to 2021 were studied. The results showed that SPEI‐1 and SPEI‐6 exhibited negative trends and periodic change. This drought aggravation was manifested in increased grades and numbers of drought months. Flash droughts can occur every month during the growing season. And its occurrence was not only positively correlated with all drought events in frequency but also synchronized in time. The increased number of DS showed an asymmetrical shift towards 7‐day‐and‐longer DS. SPEI sensitivity to precipitation (P) was noticeably higher than to atmospheric evapotranspiration demand (AED) at both monthly and growing season scales. SPEI sensitivity to AED was modulated by P amounts, which was higher during low P period. Apart from the amounts of P and AED, their temporal variability also strongly determined how they affect the drought severity. P was also the main driver for flash drought and long DS, but AED with larger amount and higher variability is the reason for their aggravation. Our results demonstrate the complexity of drought intensification in semi‐arid sandy grasslands and highlight the important role of AED anomalies in it. [ABSTRACT FROM AUTHOR]

Background: Under the background of global warming, the intensity and frequency of extreme meteorological events in the maize growing season in northeast China are increasing. In order to clarify the occurrence characteristics of extreme meteorological events in northeast China, this study focused on three extreme agrometeorological events, i.e., high temperatures, drought, and the compound events of high‐temperature and drought during the maize growing season (May–September), impacting maize production. Results: Based on historical (1981–2017) and future (2021–2060) climate data, we analyzed the spatial‐temporal patterns of these three events with different intensities in northeast China. The results indicated that slight high‐temperatures and moderate and severe droughts occurred more frequently in the study area during the historical period. The frequency of the different grades of the compound events of high‐temperature and drought will exhibit an increasing trend in the future, as will the frequency of the compound events of high‐temperature and drought. This is particularly evident in the northwest of the study area. Conclusion: The compound events of high‐temperature and drought mainly occurred in late July and early August, encompassing the flowering stage of maize varieties. It is important to identify the area and time of major extreme weather events to implement the necessary preventive measures. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Questions: Drought timing during the growing season can profoundly influence plant diversity and cover, with subsequent impacts on ecosystem functions and services in terrestrial environments. However, the different responses of plant communities to drought in different periods of the growing season remain uncertain. Location: The research was conducted in a semi‐arid grassland at the Duolun Restoration Ecology Research and Demonstration Station, in Inner Mongolia, China. Methods: The responses of plant species richness and cover to early‐ and late‐season drought with a four‐year field experiment were examined in a semi‐arid grassland in northern China. Soil moisture at different depths was measured to explore the underlying mechanisms of the drought effects on plant richness and cover. Results: Over the four years, late‐ rather than early‐season drought suppressed plant richness. Decreased species richness (−1.65 species) under late‐season drought was mainly due to suppressed perennial forb richness (−1.88 species). Late‐season drought also exerted greater negative effects on plant cover than early‐season drought. Effects of late‐season drought on plant cover depended on annual precipitation. Reduced plant cover (−7.5%) under early‐season drought stemmed from declines in shrubs and semi‐shrubs, particularly Artemisia frigida cover (−4.9%), which is sensitive to water deficits because of its shallow root depth (14.01 cm). Declined plant cover (−39.0%) under late‐season drought was mainly caused by suppressed perennial forb (−21.5%) and shrub and semi‐shrubs cover (−17.4%). The combined effects of early‐ and late‐season drought on plant cover were greater than the treatment alone, likely due to aggravating water deficits under growing‐season drought. Conclusions: Our results suggest late‐season drought is more critical for shifting plant communities. than early‐season drought. Our findings highlight the regulatory role of drought timing on plant community composition and development in arid and semi‐arid regions. [ABSTRACT FROM AUTHOR]