PRS Publications

Food production is essential. Western Ag's lab is OPEN and receiving shipments of samples.

Have this publication emailed to you.

Contrasting effects of elevated CO2 and warming on nitrogen cycling in a semiarid grassland

Dijkstra, F.A., D. Blumenthal, J.A. Morgan, E. Pendall, Y. Carrillo and R.F. Follett. 2010. New Phytologist 187:426-437

Abstract

Simulation models indicate that the nitrogen (N) cycle plays a key role in how other ecosystem processes such as plant productivity and carbon (C) sequestration respond to elevated CO2 and warming. However, combined effects of elevated CO2 and warming on N cycling have rarely been tested in the field. Here, we studied N cycling under ambient and elevated CO2 concentrations (600 umol mol-1), and ambient and elevated temperature (1.5 : 3.0°C warmer day:night) in a full factorial semiarid grassland field experiment in Wyoming, USA. We measured soil inorganic N, plant and microbial N pool sizes and NO3- uptake (using a 15N tracer). Soil inorganic N significantly decreased under elevated CO2, probably because of increased microbial N immobilization, while soil inorganic N and plant N pool sizes significantly increased with warming, probably because of increased N supply. We observed no CO2 X warming interaction effects on soil inorganic N, N pool sizes or NO3- uptake in plants and microbes. Our results indicate a more closed N cycle under elevated CO2 and a more open N cycle with warming, which could affect long-term N retention, plant productivity, and C sequestration in this semiarid grassland.