Nitrogen supply modulates the effect of changes in drying-rewetting frequency on soil C and N cycling and greenhouse gas exchange.
Climate change and atmospheric nitrogen (N) deposition are two of the most important global change drivers. However, the interactions of these drivers have not been well studied. We aimed to assess how the combined effect of soil N additions and more frequent soil drying-rewetting events affects carbon (C) and N cycling, soil:atmosphere greenhouse gas (GHG) exchange, and functional microbial diversity. We manipulated the frequency of soil drying-rewetting events in soils from ambient and N-treated plots in a temperate forest and calculated the Orwin & Wardle Resistance index to compare the response of the different treatments. Increases in drying-rewetting cycles led to reductions in soil NO3- levels, potential net nitrification rate, and soil : atmosphere GHG exchange, and increases in NH4+ and total soil inorganic N levels. N-treated soils were more resistant to changes in the frequency of drying-rewetting cycles, and this resistance was stronger for C- than for N-related variables. Both the long-term N addition and the drying-rewetting treatment altered the functionality of the soil microbial population and its functional diversity. Our results suggest that increasing the frequency of drying-rewetting cycles can affect the ability of soil to cycle C and N and soil : atmosphere GHG exchange and that the response to this increase is modulated by soil N enrichment.
Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Seville, Spain.|Department of Sciences for Nature and Environmental Resources, University of Sassari, Via Enrico de Nicola, n 9, 07100, Sassari, Italy.
Lourdes
L
Morillas
Department of Life Sciences, Center for Functional Ecology, University of Coimbra, Coimbra, Portugal.
Jorge
J
Durán
Department of Biogeography and Global Change, Science National Museum-CSIC, Madrid, Spain.
Alexandra
A
Rodríguez
Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Seville, Spain.
Javier
J
Roales
Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Seville, Spain.
Antonio
A
Gallardo
Cary Institute of Ecosystem Studies, Millbrook, NY, USA.
Gary M
GM
Lovett
Cary Institute of Ecosystem Studies, Millbrook, NY, USA.
Peter M
PM
Groffman
D057486:Carbon Cycle; D057231:Climate Change; D055864:Droughts; D065928:Forests; D017752:Greenhouse Effect; D009518:New York; D058458:Nitrogen Cycle; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
D012987:Soil
Global change; MicroResp; microbial functional diversity; nitrogen addition; nutrient cycling; precipitation pattern; soil respiration