Related Experiment Video
Updated: Sep 26, 2026

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function
Published on: November 21, 2015
Responses of soil nitrogen dynamics in a Mojave Desert ecosystem to manipulations in soil carbon and nitrogen
S M Schaeffer1, S A Billings, R D Evans
1601 Science and Engineering Building, University of Arkansas Stable Isotope Laboratory, University of Arkansas, Fayetteville 72701, USA. smschae@uark.edu
Abstract:
We investigated the effects of changes in soil C and N availability on N mineralization, nitrification, denitrification, NH(3) 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 CO(2 ) flux, lower rates of NH(3) volatilization, and a decrease in inorganic N (NH(4)(+)-N and NO(3)(-)-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 CO(2) concentration.
Related Concept Videos
Soil Microbial Ecology
The Nitrogen Cycle
Inorganic Nitrogen Assimilation
The Soil Ecosystem
Overview of Nitrogen Metabolism
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The Roles of Bacteria and Fungi in Plant Nutrition
