INVESTIGADORES
JOBBAGY GAMPEL Esteban Gabriel
artículos
Título:
The uplift of nutrients by plants: Consequences across scales
Autor/es:
JOBBAGY, EG; JACKSON, RB
Revista:
ECOLOGY
Editorial:
Ecological Society of America
Referencias:
Lugar: Brooklyn; Año: 2004 vol. 85 p. 2380 - 2389
ISSN:
0012-9658
Resumen:
Although the bulk of plant biomass contains
relatively light, atmospherically derived elements (C, H, O, N, and S), 510%
of biomass is composed of heavier elements from soil minerals, such as Ca, Mg,
K, and P. Plant uptake and cycling transport these heavier elements to the soil
surface, resulting in shallower vertical distributions for strongly cycled
elements than for other elements. In this paper, we evaluate the biogeochemical
consequences of this process at different spatial and temporal scales based on
chronosequence studies and soil database analyses. In the bare coastal dunes of
Argentina, the vertical distributions of exchangeable K1 (strongly cycled) and Na1 (more weakly cycled) were similar initially
but diverged 15 years after pine afforestation, with K distributions becoming
significantly concentrated in the surface and Na distributions becoming deeper.
To evaluate the effects of plant stoichiometry on micronutrient distributions,
chronosequences of paired native grasslands (low Mn cycling) and eucalypt
plantations (high Mn cycling) in the pampas of Argentina were also used. Within
50 years, eucalypts dramatically redistributed Mn pools toward the soil
surface, reducing total pools by half at medium depths (2060 cm) and increasing concentrations
by up to an order of magnitude at the surface. Globally, we used generalized
contrasts among exchangeable K, Na, and Mg in 7661 soil profiles to estimate
the global magnitude of K uplift due to plant activity. Based on this calculation, the exchangeable K pool
in the top 20 cm of soils without plant uplift would be 46 3 1015 g smaller globally,
one-third to one-half smaller than its current size. Vegetation change alters
the vertical distribution and bioavailability of mineral elements. Understanding how the stoichiometry of plant
cycling affects soil nutrient distributions will help refine predictions of the
biogeochemical consequences of current vegetation change.