ID:
publications-1725
Type:
Peer reviewed articles
Year:
2022
Authors:
Zheng, F., Prentice, I.C
Title:
Critical soil moisture thresholds of plant water stress in terrestrial ecosystems.
Venue/Journal:
Science Advances
DOI:
10.1126/sciadv.abq7827
Research type:
IoT & Sensors
Water System:
Wastewater Treatment Plants
Technical Focus:
Abstract:
Plant water stress occurs at the point when soil moisture (SM) limits transpiration, defining a critical SM threshold (θ crit ). Knowledge of the spatial distribution of θ crit is crucial for future projections of climate and water resources. Here, we use global eddy covariance observations to quantify θ crit and evaporative fraction (EF) regimes. Three canonical variables describe how EF is controlled by SM: the maximum EF (EF max ), θ crit , and slope (S) between EF and SM. We find systematic differences of these three variables across biomes. Variation in θ crit , S, and EF max is mostly explained by soil texture, vapor pressure deficit, and precipitation, respectively, as well as vegetation structure. Dryland ecosystems tend to operate at low θ crit and show adaptation to water deficits. The negative relationship between θ crit and S indicates that dryland ecosystems minimize θ crit through mechanisms of sustained SM extraction and transport by xylem. Our results further suggest an optimal adaptation of local EF-SM response that maximizes growing-season evapotranspiration and photosynthesis.
Link with Projects:
787203
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