Accelerated soil drying linked to increasing evaporative demand in wet regions

Abstract

The rapid decline in soil water affects water resources, plant physiology, and agricultural development. However, the changes in soil drying rate and associated climatic mechanisms behind such changes remain poorly understood. Here, we find that wet regions have witnessed a significant increasing trend in the soil drying rate during 1980-2020, with an average increase of 6.01 - 9.90% per decade, whereas there is no consistent trend in dry regions. We also identify a near-linear relationship between the annual soil drying rate and its influencing factors associated with atmospheric aridity and high temperatures. Further, enhanced evapotranspiration by atmospheric aridity and high temperatures is the dominant factor increasing the soil drying rate in wet regions. Our results highlight the accelerated soil drying in the recent four decades in wet regions, which implies an increased risk of rapidly developing droughts, posing a serious challenge for the adaptability of ecosystems and agriculture to rapid drying.