Bringing function to structure: Root–soil interactions shaping phosphatase activity throughout a soil profile in Puerto Rico

Kristine Grace Cabugao, Daniela Yaffar, Nathan Stenson, Joanne Childs, Jana Phillips, Melanie A. Mayes, Xiaojuan Yang, David J. Weston, Richard J. Norby

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Large areas of highly productive tropical forests occur on weathered soils with low concentrations of available phosphorus (P). In such forests, root and microbial production of acid phosphatase enzymes capable of mineralizing organic phosphorus is considered vital to increasing available P for plant uptake. We measured both root and soil phosphatase throughout depth and alongside a variety of root and soil factors to better understand the potential of roots and soil biota to increase P availability and to constrain estimates of the biochemical mineralization within ecosystem models. We measured soil phosphatase down to 1 m, root phosphatase to 30 cm, and collected data on fine-root mass density, specific root length, soil P, bulk density, and soil texture using soil cores in four tropical forests within the Luquillo Experimental Forest in Puerto Rico. We found that soil phosphatase decreased with soil depth, but not root phosphatase. Furthermore, when both soil and root phosphatase were expressed per soil volume, soil phosphatase was 100-fold higher that root phosphatase. Both root and soil factors influenced soil and root phosphatase. Soil phosphatase increased with fine-root mass density and organic P, which together explained over 50% of the variation in soil phosphatase. Over 80% of the variation in root phosphatase per unit root mass was attributed to specific root length (positive correlation) and available (resin) P (negative correlation). Synthesis: Fine-root traits and soil P data are necessary to understand and represent soil and root phosphatase activity throughout the soil column and across sites with different soil conditions and tree species. These findings can be used to parameterize or benchmark estimates of biochemical mineralization in ecosystem models that contain fine-root biomass and soil P distributions throughout depth.

Original languageEnglish
Pages (from-to)1150-1164
Number of pages15
JournalEcology and Evolution
Volume11
Issue number3
DOIs
StatePublished - Feb 2021

Funding

This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This research was supported as part of the Next Generation Ecosystem Experiments-Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (DE-AC05-00OR22725). We would also like to acknowledge the U.S. Department of Agriculture Forest Service International Institute of Tropical Forestry, The University of Puerto Rico and the El Verde Field Station for access to the Luquillo Experimental Forest field sites and for coordination during sampling. We also thank Dr. Dale Pelletier at ORNL for generously providing laboratory space for phosphatase assays and Dr. Josh Price at the Office of Information Technology at the University of Tennessee Knoxville for providing guidance on statistical analyses. This manuscript has been authored by UT‐Battelle, LLC under Contract No. DE‐AC05‐00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid‐up, irrevocable, world‐wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe‐public‐access‐plan ). This research was supported as part of the Next Generation Ecosystem Experiments‐Tropics, funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (DE‐AC05‐00OR22725). We would also like to acknowledge the U.S. Department of Agriculture Forest Service International Institute of Tropical Forestry, The University of Puerto Rico and the El Verde Field Station for access to the Luquillo Experimental Forest field sites and for coordination during sampling. We also thank Dr. Dale Pelletier at ORNL for generously providing laboratory space for phosphatase assays and Dr. Josh Price at the Office of Information Technology at the University of Tennessee Knoxville for providing guidance on statistical analyses.

FundersFunder number
DOE Public Access Plan
Office of Information Technology at the University of Tennessee Knoxville
U.S. Department of Agriculture Forest Service International Institute of Tropical Forestry
United States Government
U.S. Department of Energy
Office of Science
Biological and Environmental ResearchDE‐AC05‐00OR22725
Oak Ridge National Laboratory
Universidad de Puerto Rico

    Keywords

    • phosphatase activity
    • plant
    • root traits
    • soil (belowground) interactions
    • soil phosphorus availability
    • tropical forest

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