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dc.contributor.authorEspeleta, Javier F.  Concept link
dc.contributor.authorCardon, Zoe G.  Concept link
dc.contributor.authorMayer, K. Ulrich  Concept link
dc.contributor.authorNeumann, Rebecca B.  Concept link
dc.identifier.citationPlant and Soil 414 (2017): 33-51en_US
dc.description© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Plant and Soil 414 (2017): 33-51, doi:10.1007/s11104-016-3089-5.en_US
dc.description.abstractHydro-biogeochemical processes in the rhizosphere regulate nutrient and water availability, and thus ecosystem productivity. We hypothesized that two such processes often neglected in rhizosphere models — diel plant water use and competitive cation exchange — could interact to enhance availability of K+ and NH4+, both high-demand nutrients. A rhizosphere model with competitive cation exchange was used to investigate how diel plant water use (i.e., daytime transpiration coupled with no nighttime water use, with nighttime root water release, and with nighttime transpiration) affects competitive ion interactions and availability of K+ and NH4+. Competitive cation exchange enabled low-demand cations that accumulate against roots (Ca2+, Mg2+, Na+) to desorb NH4+ and K+ from soil, generating non-monotonic dissolved concentration profiles (i.e. ‘hotspots’ 0.1–1 cm from the root). Cation accumulation and competitive desorption increased with net root water uptake. Daytime transpiration rate controlled diel variation in NH4+ and K+ aqueous mass, nighttime water use controlled spatial locations of ‘hotspots’, and day-to-night differences in water use controlled diel differences in ‘hotspot’ concentrations. Diel plant water use and competitive cation exchange enhanced NH4+ and K+ availability and influenced rhizosphere concentration dynamics. Demonstrated responses have implications for understanding rhizosphere nutrient cycling and plant nutrient uptake.en_US
dc.description.sponsorshipThis material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Biological & Environmental Research Terrestrial Ecosystem Science program under Award Number DE-SC0008182 to Z.G.C. and R.B.N.en_US
dc.rightsAttribution 4.0 International*
dc.subjectHydraulic redistributionen_US
dc.subjectNighttime transpirationen_US
dc.subjectPlant nutrient uptakeen_US
dc.subjectRoot water uptakeen_US
dc.titleDiel plant water use and competitive soil cation exchange interact to enhance NH4+ and K+ availability in the rhizosphereen_US

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Attribution 4.0 International
Except where otherwise noted, this item's license is described as Attribution 4.0 International