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

This Article Figures Only Full Text Free Full Text (PDF) Free 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 Google Scholar Google Scholar Articles by Fröberg, M. Articles by Garten, C. T. Search for Related Content PubMed Articles by Fröberg, M. Articles by Garten, C. T., Jr. GeoRef GeoRef Citation Agricola Articles by Fröberg, M. Articles by Garten, C. T. Related Collections Isotopes Soil Organic Matter Biogeochemical Processes

SOIL BIOLOGY & BIOCHEMISTRY

Low Dissolved Organic Carbon Input from Fresh Litter to Deep Mineral Soils

^a Environmental Sciences Division, Oak Ridge National Laboratory Oak Ridge, TN 37831-6422
^b Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550
^c Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422

^* Corresponding author (froebergmj{at}ornl.gov).

Dissolved organic carbon (DOC) leached from recent litter in the forest floor has been suggested to be an important source of C to the mineral soil of forest ecosystems. To determine the rate at which this flux of C occurs, we have taken advantage of a local release of ¹⁴C at Oak Ridge National Laboratory Reservation, Oak Ridge, TN (35°58'N, 84°16'W). Eight replicate 7- by 7-m plots were established at four field sites on the reservation in an upland oak forest setting. Half of the plots were provided with ¹⁴C-enriched litter (¹⁴C 1000), and the other half with near-background litter (¹⁴C 220) for multiple years. Differences in the labeled leaf litter were used to quantify the movement of litter-derived DOC through the soil profile. Soil solutions were collected for several years with tension lysimeters at 15- and 70-cm depths and measured for DOC concentration and ¹⁴C abundance. The net amount of DOC retained between 15 and 70 cm was between 2 and 10 g m^–2 yr^–1. There were significant effects of the litter additions on the ¹⁴C abundance in the DOC, but the net transport of ¹⁴C from the added litter was small. The difference in ¹⁴C between the treatments with enriched and near-background litter was only about 130 at both depths, which is small compared with the difference in ¹⁴C in the added litter. The primary source of DOC within the mineral soil must therefore have been either the Oe or Oa horizon or the organic matter in the mineral soil. During a 2-yr time frame, leaching of DOC from recent litter did not have a major impact on the C stock in the mineral soil below 15 cm in this ecosystem.

Abbreviations: DOC, dissolved organic carbon • EBIS, Enriched Background Isotope Study • ORR, Oak Ridge Reservation • TVA, Tennessee Valley Authority