Diel plant water use and competitive soil cation exchange interact to enhance NH4 and K availability in the rhizosphereReportar como inadecuado




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Plant and Soil

, Volume 414, Issue 1–2, pp 33–51

First Online: 12 November 2016Received: 11 May 2016Accepted: 14 October 2016DOI: 10.1007-s11104-016-3089-5

Cite this article as: Espeleta, J.F., Cardon, Z.G., Mayer, K.U. et al. Plant Soil 2017 414: 33. doi:10.1007-s11104-016-3089-5

Abstract

AimsHydro-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.

MethodsA 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.

ResultsCompetitive cation exchange enabled low-demand cations that accumulate against roots Ca, Mg, 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.

ConclusionsDiel 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.

KeywordsHydraulic redistribution Nighttime transpiration Plant nutrient uptake Reactive-transport Rhizosphere Root water uptake Responsible Editor: Ellis Hoffland.

Electronic supplementary materialThe online version of this article doi:10.1007-s11104-016-3089-5 contains supplementary material, which is available to authorized users.





Autor: Javier F. Espeleta - Zoe G. Cardon - K. Ulrich Mayer - Rebecca B. Neumann

Fuente: https://link.springer.com/







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