Water wranglers in the West -- How much water can sagebrush roots move up and down in soil?
Dr. Zoe Cardon and Dr. Rebecca Neumann
Observations of soil moisture in the dry Rush Valley, Utah landscape suggest that as much as ¾ of the rainwater falling each year may be redistributed very rapidly to deep soil not just by percolation but instead moved and "stored" deep by sagebrush roots. Sagebrush shrubs are common in Great Basin U.S. ecosystems, becoming more dominant with the increased grazing that has accompanied human settlement in the last 150 years. Water travels through the sagebrush roots, through miniscule, open pipes in the roots’ centers, tending to equalize the water content of soil around the entire sagebrush root system. This redistribution of water is likely a major controller of hydrology at the landscape scale in Western ecosystems where sagebrush are dominant and water conservation is becoming more and more important. Cardon and colleagues are exploring just how much water is being moved through sagebrush roots, up and down in the soil, on BLM grazing lands near Laketown, Utah.
Water isn’t the only limitation on plant productivity in such ecosystems, however. Nitrogen availability can also be sub-optimal, and Cardon and colleagues are also investigating how rates of nutrient cycling (and associated nutrient delivery to plants) catalyzed by soil microbes living among sagebrush roots are affected by root-mediated redistribution of water.
Sagebrush growing in the greenhouse are being prepared for further, controlled laboratory experiments exploring water redistribution by their root systems, and exploration of interactions among roots and soil microbes.