HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Google Scholar Articles by Vargas, R. Articles by Allen, M. F. PubMed Articles by Vargas, R. Articles by Allen, M. F. GeoRef GeoRef Citation Agricola Articles by Vargas, R. Articles by Allen, M. F. Related Collections Root Growth Biogeochemical Processes Hysteresis

SPECIAL SECTION: ROOTS AND ROOT FUNCTION

Dynamics of Fine Root, Fungal Rhizomorphs, and Soil Respiration in a Mixed Temperate Forest: Integrating Sensors and Observations

Center for Conservation Biology, Univ. of California-Riverside, Riverside, CA 92521. R. Vargas, current address, Dep. of Environmental Science, Policy, and Management (ESPM), Ecosystem Science Division, Univ. of California-Berkeley, Berkeley, CA 94720
^* Corresponding author (rvargas{at}nature.berkeley.edu).

Received 5 August 2007.

Fine roots and rhizomorphs have important implications for the global carbon balance, but the processes underlying these carbon sinks are not well understood. In this study, we coupled continuous minirhizotron observations with an array of solid-state CO₂ sensors. We calculated soil respiration using a gradient flux method. Using a Kaplan-Maier survival analysis, we determined a median longevity of 347 d for fine roots and of 400 d for rhizomorphs. Radiocarbon (¹⁴C) analysis suggested an age of 7 yr for fine roots <1 mm and 17 yr for roots of 1 mm in diameter. We found rapid changes in root length (maximum of 38.1 cm m^–2 d^–1) and rhizomorph length (maximum of 105.4 cm m^–2 d^–1) during sampling of four consecutive days. Changes in rhizomorph length were more variable than root length, and rhizomorphs were negatively correlated with daily changes in soil moisture. The variation in root length may be associated to prior environmental conditions. Fine root length was correlated with daily CO₂ production, and variation in daily fine root length could contribute up to 4680 g C ha^–1 d^–1. We observed a clockwise diurnal hysteresis effect in soil respiration with soil temperature that changed in amplitude and shape along the year. Our results show the importance of shorter intervals of minirhizotron measurements to understand rapid fine roots and rhizomorphs variation. Furthermore, continuous minirhizotron measurements should be couple with continuous measurements of multiple sensor arrays to explain biophysical factors that regulate belowground carbon dynamics.

Abbreviations: AM, arbuscular mycorrhizae • CENS, Center for Embedded Networked Sensing • EM, ectomycorrhizae • UC, University of California • VWC, volumetric water content

This article has been cited by other articles:

				T. H. Skaggs and P. J. Shouse Roots and Root Function: Introduction Vadose Zone J., August 1, 2008; 7(3): 1008 - 1009. [Full Text] [PDF]