Title: A scalable multi-process model of root nitrogen uptake

Abstract

This article is a Commentary on McMurtrie & Näsholm et al., 218: 119–130. Roots are represented in Terrestrial Ecosystem Models (TEMs) in much less detail than their equivalent above-ground resource acquisition organs – leaves. Often roots in TEMs are simply resource sinks, and below-ground resource acquisition is commonly simulated without any relationship to root dynamics at all, though there are exceptions (e.g. Zaehle & Friend, 2010). The representation of roots as carbon (C) and nitrogen (N) sinks without complementary source functions can lead to strange sensitivities in a model. For example, reducing root lifespans in the Community Land Model (version 4.5) increases plant production as N cycles more rapidly through the ecosystem without loss of plant function (D. M. Ricciuto, unpublished). The primary reasons for the poorer representation of roots compared with leaves in TEMs are three-fold: (1) data are much harder won, especially in the field; (2) no simple mechanistic models of root function are available; and (3) scaling root function from an individual root to a root system lags behind methods of scaling leaf function to a canopy. Here in this issue of New Phytologist, McMurtrie & Näsholm (pp. 119–130) develop a relatively simple model for root Nmore » uptake that mechanistically accounts for processes of N supply (mineralization and transport by diffusion and mass flow) and N demand (root uptake and microbial immobilization).« less

Authors:

Walker, Anthony P. ^[1]

---

+ Show Author Affiliations

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. & Environmental Sciences Division

Publication Date:

Wed Feb 28 00:00:00 EST 2018

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1436945

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

New Phytologist

Additional Journal Information:

Journal Volume: 218; Journal Issue: 1; Journal ID: ISSN 0028-646X

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; diffusion; mass flow; microbial nitrogen immobilization; nitrogen mineralization; root nitrogen uptake model; soil nitrogen transport; models as hypotheses; Terrestrial Ecosystem Models (TEMs)