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 Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Idol, T. W. Articles by Ponder, F. Search for Related Content PubMed Articles by Idol, T. W. Articles by Ponder, F., Jr. Agricola Articles by Idol, T. W. Articles by Ponder, F. Related Collections Soil Microbiology Forest Soils Nutrient Cycling

DIVISION S-7—FOREST & RANGE SOILS

Changes in Microbial Nitrogen Across a 100-Year Chronosequence of Upland Hardwood Forests

^a Dep. of Land, Air, and Water Resources, Univ. of California-Davis, One Shields Ave, Davis, CA 95616
^b Dep. of Forestry and Natural Resources, Purdue Univ., 1159 Forestry Bldg, West Lafayette, IN 47907
^c USDA-Forest Service, North Central Research Station, 208 Foster Hall, Chestnut St., Lincoln Univ., Jefferson University, MO 65102

* Corresponding author (twidol{at}ucdavis.edu)

Soil microorganisms mediate many of the major processes involved in soil N cycling. Also, they are strong competitors with plants for available soil N. Thus, changes in microbial N because of forest harvesting may have significant impacts on N availability and overall forest N cycling. A chronosequence of upland hardwood forest stands in southern Indiana, USA, ranging in age from 1 to 100 yr since last harvest, was chosen to evaluate changes in microbial N with stand development. Microbial N was measured in the A and B soil horizons during different seasons from 1997 to 1999. Peak levels of microbial N were highest in the youngest forest stand (1 to 3 yr old), but seasonal variability was greater than differences by stand age. Microbial N concentration (mg kg^-1) varied significantly by season and soil horizon within stands ranging in age from 1 to 30 yr since harvest, but not in the mature, 80- to 100-yr-old stand. There were few significant differences in microbial N content (kg ha^-1). Harvesting did not appear to have long-term effects on microbial N, but spatial variability in microbial N appeared to be greater in the younger forest stands.