Iron reduction: a mechanism for dynamic cycling of occluded cations in tropical forest soils?

dc.contributor.author Hall, Steven
dc.contributor.author Huang, Wenjuan
dc.contributor.author Hall, Steven
dc.contributor.department Ecology, Evolution and Organismal Biology
dc.date 2018-02-19T07:33:00.000
dc.date.accessioned 2020-06-30T02:17:32Z
dc.date.available 2020-06-30T02:17:32Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 2017
dc.date.embargo 2018-10-01
dc.date.issued 2017-10-01
dc.description.abstract <p>Nutrient cations can limit plant productivity in highly weathered soils, but have received much less attention than phosphorus and nitrogen. The reduction of iron (Fe) in anaerobic microsites of surface soils can solubilize organic matter and P sorbed or occluded with short-range-ordered (SRO) Fe phases. This mechanism might also release occluded cations. In the Luquillo Experimental Forest, Puerto Rico, we measured cation release during anaerobic laboratory incubations, and assessed patterns of cation availability in surface soils spanning ridge-slope-valley catenas. During anaerobic incubations, potassium (K), calcium (Ca) and magnesium (Mg) significantly increased with reduced Fe (Fe(II)) in both water and 0.5M HCl extractions, but did not change during aerobic incubations. In the field, 0.5M HCl-extractable Fe(II) and Fe(III) were the strongest predictors of K, Mg, and Ca on ridges (R2: 0.57 – 0.75). Here, both Ca and Mg decreased with Fe(III), while K, Ca, and Mg increased with Fe(II), consistent with release of Fe-occluded cations following Fe reduction. Manganese in ridge soils was extremely low, consistent with leaching following reductive dissolution of Mn(IV). On slopes, soil C was the strongest cation predictor, consistent with the importance of organic matter for cation exchange in these highly weathered Oxisols. In riparian valleys, cation concentrations were up to 16-fold greater than in other topographic positions but were weakly or unrelated to measured predictors, potentially reflecting cation-rich groundwater. Predictors of cation availability varied with topography, but were consistent with the potential importance of microsite Fe reduction in liberating occluded cations, particularly in the highly productive ridges. This mechanism may explain discrepancies among indices of “available” soil cations and plant cation uptake observed in other tropical forests.</p>
dc.description.comments <p>This is a post-peer-review, pre-copyedit version of an article published in Biogeochemistry. The final authenticated version is available online at: <a href="http://dx.doi.org/10.1007/s10533-017-0383-0" target="_blank">http://dx.doi.org/10.1007/s10533-017-0383-0</a>.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/eeob_ag_pubs/250/
dc.identifier.articleid 1255
dc.identifier.contextkey 11375930
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath eeob_ag_pubs/250
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/23124
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/eeob_ag_pubs/250/2017_Hall_IronReductionManuscript.pdf|||Fri Jan 14 22:57:08 UTC 2022
dc.source.uri 10.1007/s10533-017-0383-0
dc.subject.disciplines Biogeochemistry
dc.subject.disciplines Ecology and Evolutionary Biology
dc.subject.disciplines Forest Sciences
dc.subject.disciplines Soil Science
dc.subject.keywords cation
dc.subject.keywords Luquillo Experimental Forest
dc.subject.keywords iron
dc.subject.keywords occluded
dc.subject.keywords redox
dc.subject.keywords Walker-Syers model
dc.title Iron reduction: a mechanism for dynamic cycling of occluded cations in tropical forest soils?
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 3f4318fa-b172-4017-b69d-49d5e3607c4f
relation.isOrgUnitOfPublication 6fa4d3a0-d4c9-4940-945f-9e5923aed691
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