BECAS
MUJICA Claudio Ramon
artículos
Título:
Modeling soil chemical changes induced by grassland afforestation in a sedimentary plain with shallow groundwater
Autor/es:
MUJICA, CLAUDIO R.; BEA, SERGIO A.; JOBBÁGY, ESTEBAN G.
Revista:
GEODERMA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2021 vol. 400
ISSN:
0016-7061
Resumen:
Chemical changes produced by the establishment of tree plantations on grasslands occupying sedimentary plainscould potentially impact their highly productive soils through multiple mechanisms. Some of the reportedchemical changes following this vegetation shift include soil salinization, sodification, alkalization and acidification.While the associated hydrological, chemical and biological processes have been characterized in mostcases, their quantitative integration remains as a complex challenge. The present work explored the simultaneousoccurrence of the four mentioned soil chemical changes using reactive transport modeling and hydrological andchemical datasets (water, soil and plants) for a well described afforested grassland in the Pampas of Argentina.Processes included in the numerical model were unsaturated water flow, chemical reactions (soil cation exchange,mineral dissolution-precipitation), the intrusion of salty deep water induced by tree groundwater consumption,rhizosphere-plant processes (respiration, selective solute uptake/exclusion, root mediated electriccharge compensation, and elemental recycling and uplift). Modeling results suggest that the dominant soilchemical changes depend on the interplay of all the aforementioned processes and help explain strong soilvariation across very short distances (250 m) along edge-core gradients within the tree plantation. Thiscomplexity is hard to expect and explain from an isolated treatment of each of the aforementioned processes,calling for the application of numerical tools.