Substantial changes in podzol morphology after tree‐roots modify soil porosity and hydrology in a tropical coastal rainforest

Pedro Martinez*, Peter Buurman, Diego Luciano do Nascimento, Vance Almquist, Pablo Vidal-Torrado

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Aims: We investigated morphological variations in podzols caused by changes in soil porosity and permeability upon the growth of large tree-roots in a tropical barrier island (Ilha Comprida, Brazil). Methods: Soil morphology was described in a continuous lateral sequence of podzols on a 35 m-long cliff. A soil thin section was used to characterize organic matter (OM) accumulation and to estimate soil porosity, permeability, and saturated hydraulic conductivity (Ksat). Soil texture and the contents of organic carbon, Al, and Fe were determined for each pedogenic horizon containing large tree-roots. The evolution of podzol morphology was interpreted in the context of age determinations by optically stimulated luminescence and 14C. Results: Taproots of cashew trees (Anacardium occidentale) penetrated the cemented Bhm horizon and the massive-clayey 2Cgj horizon. Aligned with the taproot, we found a vertical OM-band with lower porosity, permeability, and Ksat than the adjacent Bh and E horizons. Irregular or broken boundaries between the E and Bh horizons were caused by large tree-roots. While the maximum age of these podzols is 3390 ± 530 years, significant and rapid changes in the Bh-horizon morphology occurred within the lifetime of the cashew trees (~ 50 years). Conclusions: The interplay between reduction in flow adjacent to large taproots and the enhanced vertical infiltration at depth has resulted into the development of irregular and broken boundaries between the E and Bh horizons. Because tree-roots alter both local soil porosity and water flow paths, they simultaneously cause the formation and degradation of podzol Bh-horizon.

Original languageEnglish
JournalPlant and Soil
DOIs
Publication statusE-pub ahead of print - 1 Mar 2021

Keywords

  • Anacardium occidentale
  • Bioturbation
  • Drainage
  • Ilha Comprida
  • Podzolisation

Fingerprint Dive into the research topics of 'Substantial changes in podzol morphology after tree‐roots modify soil porosity and hydrology in a tropical coastal rainforest'. Together they form a unique fingerprint.

Cite this