Oecologia

, Volume 134, Issue 4, pp 547–553

Responses of soil nitrogen dynamics in a Mojave Desert ecosystem to manipulations in soil carbon and nitrogen availability

Ecosystems Ecology

Abstract

We investigated the effects of changes in soil C and N availability on N mineralization, nitrification, denitrification, NH3 volatilization, and soil respiration in the Mojave Desert. Results indicate a C limitation to microbial N cycling. Soils from underneath the canopies of Larrea tridentata (DC.) Cov., Pleuraphis rigida Thurber, and Lycium spp. exhibited higher rates of CO2 flux, lower rates of NH3 volatilization, and a decrease in inorganic N (NH4+-N and NO3--N) with C addition. In addition to C limitation, soils from plant interspaces also exhibited a N limitation. Soils from all locations had net immobilization of N over the course of a 15-day laboratory incubation. However, soils from interspaces had lower rates of net nitrification and potential denitrification compared to soils from under plant canopies. The response to changes in C availability appears to be a short-term increase in microbial immobilization of inorganic N. Under controlled conditions, and over a longer time period, the effects of C and N availability appear to give way to larger differences due to spatial location. These findings have implications for ecosystems undergoing changes in soil C and N availability due to such processes as desertification, exotic species invasions, or elevated atmospheric CO2 concentration.

Keywords

Ammonia volatilization Denitrification Microbial activity Mineralization Soil respiration 

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • S. M. Schaeffer
    • 1
  • S. A. Billings
    • 1
  • R. D. Evans
    • 1
  1. 1.601 Science and Engineering Building, University of Arkansas Stable Isotope LaboratoryUniversity of ArkansasFayettevilleUSA

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