Drought differentially affects autotrophic and heterotrophic soil respiration rates and their temperature sensitivity
Climate change predictions indicate that extreme drought is likely to become more frequent in the future. In this study, the impact of drought on soil respiration (Rs) and its autotrophic (Ra) and heterotrophic components (Rh) were studied in a cultivated Black Chernozemic soil in central Alberta, Canada. The mean Rs was 24.4% lower in the drought relative to the plots with ambient precipitation (P < 0.001), with a larger decrease in Ra (26.8%) relative to Rh (21.0%), and a higher (P < 0.05) contribution of Rh to Rs under drought (52.8%) than under the ambient condition (47.7%). Both Rs and its Ra and Rh components had an exponential relationship with soil temperature and a quadratic relationship with soil water content. Drought caused a greater decrease in the tipping point of soil water content for Rh (a 39.6% reduction) than for Ra (a 15.1% reduction) relative to the ambient precipitation treatment. In addition, drought resulted in a greater increase in the temperature sensitivity (Q10 values) of Ra (a 45.0% increase) than that of Rh (a 14.1% increase) relative to the ambient precipitation treatment. The results suggest that drought amplified the water limitation effect on CO2 emission, especially that from microbial respiration, and resulted in a tighter relationship between temperature and root or autotrophic respiration, based on this 1-year study. We conclude that it is important to assess the impact of drought on soil respiration components rather than the total soil respiration, and such differential effects of drought on soil respiration components should be incorporated into global carbon circulation models.
KeywordsAutotrophic respiration Drought Heterotrophic respiration Soil respiration Soil water content tipping point Temperature sensitivity of soil respiration (Q10)
We would like to thank Zheng Shi for technical assistance and invaluable contributions in the laboratory and field.
- Epron D (2009) Separating autotrophic and heterotrophic components of soil respiration: lessons learned from trenching and related root exclusion experiments. In: Bahn M, Heinemeyer A, Kutsch W (eds) Soil carbon dynamics: an integrated methodology. Cambridge University Press, Cambridge, pp 289–310Google Scholar
- Inglima I, Alberti G, Bertolini T, Vaccari FP, Gioli B, Miglietta F, Cotrufo MF, Peressotti A (2010) Precipitation pulses enhance respiration of Mediterranean ecosystems: the balance between organic and inorganic components of increased soil CO2 efflux. Glob Chang Biol 15:1289–1301CrossRefGoogle Scholar
- IPCC (2013) The physical science basis. Contribution of working group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. Cambridge University Press, CambridgeGoogle Scholar
- Prudhomme C, Giuntoli I, Robinson EL, Clark DB, Arnell NW, Dankers R, Fekete BM, Franssen W, Gerten D, Gosling SN, Hagemann S, Hannah DM, Kim H, Masaki Y, Satoh Y, Stacke T, Wada Y, Wisser D (2014) Hydrological droughts in the 21st century, hotspots and uncertainties from a global multimodel ensemble experiment. PNAS 111:3262–3267CrossRefGoogle Scholar
- Selsted MB, Linden L, Ibrom A, Michelsen A, Larsen KS, Pedersen JK, Mikkelsen TN, Pilegaard K, Beier C, Ambus P (2012) Soil respiration is stimulated by elevated CO2 and reduced by summer drought: three years of measurements in a multifactor ecosystem manipulation experiment in a temperate heathland (CLIMAITE). Glob Chang Biol 18:1216–1230CrossRefGoogle Scholar
- Soil Classification Working Group (1998) The Canadian system of soil classification, 3rd edn. NRC Research Press, Ottawa, p 187Google Scholar
- UKIUSS Working Group WRB (1998) World reference base for soil resources. World Soil Resources Reports 84. ISSS, FAO, ISRIC, RomeGoogle Scholar
- van der Molen MK, Dolman AJ, Ciais P, Eglin T, Gobron N, Law BE, Meir P, Peters W, Phillips OL, Reichstein M, Chen T, Dekker SC, Doubková M, Friedl MA, Jung M, van den Hurk BJJM, de Jeu RAM, Kruijt B, Ohta T, Rebel KT, Plummer S, Seneviratne SI, Sitch S, Teuling AJ, van der Werf GR, Wang G (2011) Drought and ecosystem carbon cycling. Agric For Meteorol 151:765–773CrossRefGoogle Scholar
- Wood TE, Detto M, Silver WL (2013) Sensitivity of soil respiration to variability in soil moisture and temperature in a humid tropical forest. PLoS One 8:7Google Scholar