Linking root water uptake to root traits and assessing performance of common models.
Neutron imaging is used to measure soil water movement and water uptake by individual roots in situ.
Root water uptake can be linked to characteristic root traits, such as diameter or age. Comparing actual water uptake with modeled water uptake highlights problems with current model assumptions. This work points to the need for new research to understand soil hydraulic properties with and without roots present.
Knowledge of plant root function is largely based on indirect measurements of bulk soil water or nutrient extraction, which limits modeling of root function in land surface models. Neutron radiography, complementary to X-ray imaging, was used to assess in situ water uptake from newer, finer roots and older, thicker roots of a poplar seedling growing in sand. The smaller-diameter roots had greater water uptake per unit surface area than the larger diameter roots, ranging from 0.0027 to 0.0116 g/cm2 root surface area/h. Model analysis based on root-free soil hydraulic properties indicated unreasonably large water fluxes between the vertical soil layers during the first 16 hours after wetting—suggesting problems with common soil hydraulic or root surface area modeling approaches and the need to further research and understand the impacts of roots on soil hydraulic properties.
BER Program Managers
Terrestrial Ecosystem Science
Jeffrey M Warren
Environmental Sciences Division and Climate Change Science Institute
Oak Ridge National Laboratory
Oak Ridge, TN 37831
Support from Laboratory Directed Research and Development Program at Oak Ridge National Laboratory (ORNL); Office of Biological and Environmental Research within the U.S. Department of Energy (DOE) Office of Science; DOE Office of Science's Office of Workforce Development for Teachers and Scientists; Office of Science Graduate Student Research (SCGSR) program; High Flux Isotope Reactor (HFIR), a DOE Office of Science user facility operated by ORNL.
Dhiman, I., H. Bilheux, K. DeCarlo, S.L. Painter, L. Santodonato, J.M. Warren. “Quantifying root water extraction after drought recovery using sub-mm in situ empirical data.” Plant and Soil 424, 73–89 (2018). [DOI:10.1007/s11104-017-3408-5]
SC-33.1 Earth and Environmental Sciences Division, BER
BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER
Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]
Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]
Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]
Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.
Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco
List all highlights (possible long download time)