A geostatistical approach to the field-scale pattern of heterotrophic soil CO2 emission using covariates
- 389 Downloads
Soil heterotrophic respiration fluxes at field scale may exhibit a substantial spatial variability. The aim of this study was (1) to elucidate the role of soil temperature and different carbon fractions on heterotrophic soil respiration and (2) to test by which of three different statistical approaches (multiple regression, external drift kriging and simulated annealing) such influences may be best represented. Chamber-based measurements of respiration fluxes were carried out within a 180 × 40 m bare soil plot. Soil temperature was measured simultaneously to the flux measurements. Further, we recorded total soil organic carbon content, apparent electrical conductivity as well as mid-infrared spectroscopy-based carbon fractions as co-variates in addition to basic soil properties like stone content and texture. A stepwise multiple linear regression procedure was used to spatially predict bare soil respiration from the co-variates. The results showed that the particulate organic matter (POM) fraction and terrain elevation were able to explain the spatial pattern of heterotrophic soil respiration (R 2 = 0.45). In a second step we applied external drift kriging to determine the improvement of using co-variates in an estimation procedure in comparison to ordinary kriging. The maximum relative improvement using the co-variates in terms of the root mean square error was 16%. In a third step we applied simulated annealing to perform stochastic simulations conditioned with external drift kriging to generate more realistic spatial patterns of heterotrophic respiration at plot scale. The conditional stochastic simulations revealed a significantly improved reproduction of the probability density function, the G-statistics value increased from 0.36 to 0.92. Further, the error in the reproduction of the semivariogram of the original point data decreased by more than one order of magnitude. All this confirmed that the mapping of soil respiration patterns may be significantly improved when considering terrain elevation and spatial heterogeneity of POM in combination with a conditional stochastic simulation.
KeywordsCarbon fractions Heterotrophic respiration CO2 efflux Spatial variability Carbon Pools
This research was supported by the German Research Foundation DFG (Transregional Collaborative Research Centre 32—Patterns in Soil–Vegetation–Atmosphere Systems: Monitoring, modelling and data assimilation). Alexander Graf would like to thank the DFG for funding within the project “Links between local scale and catchment scale measurements and modelling of gas exchange processes over land surfaces”. Thanks to R. Harms and M. Hank for the help with some of the measurements.
- Akaike H (1973) Information theory as an extension of the likelihood principle. In: Petrov BN, Csaki F (eds) International symposium on information theory. Akademiai Kiado, Budapest, pp 267–281Google Scholar
- Deutsch CV (1997) Direct assessment of local accuracy and precision. In: Baafi EY, Schofield NA (eds) Geostatistics Wollongong’96. Kluwer, Dordrecht, pp 115–125Google Scholar
- Deutsch CV, Journel AG (1998) GSLIB: geostatistical software library and user’s guide, 2nd edn. Oxford University Press, New York 369Google Scholar
- Graf A, Prolingheuer N, Schickling A, Schmidt M, Schneider K, Schüttemeyer D, Herbst M, Huisman JA, Weihermüller L, Scharnagl B, Steenpass C, Harms R, Vereecken H (2010) Temporal downscaling of soil CO2 efflux measurements based on time-stable patterns. Vadose Zone J 10:239–251Google Scholar
- IPCC (2007) Climate change 2007: the physical science basis. Summary for policymakersGoogle Scholar
- ISO 10694 (1995) Soil quality—determination of organic and total carbon after dry combustion (elemental analysis). Beuth-Verlag, BerlinGoogle Scholar
- ISO 11277 (2002) Soil quality—determination of particle size distribution in mineral soil material—method by sieving and sedimentation. Beuth-Verlag, BerlinGoogle Scholar
- Pacific J, McGlynn BL, Rivieros-Iregui DA, Welsch D, Epstein H (2011) Landscape structure, groundwater dynamics, and soil water content influence soil respiration across riparian-hillslope transitions in the Tenderfoot Creek Experimental Forest, Montana. Hydrol Process 25:811–827. doi: 10.1002/hyp.7870 CrossRefGoogle Scholar
- Pumpanen J, Kolari P, Ilvesniemi H, Minkkinen K, Vesala T, Niinistö S, Lohila A, Larmola T, Morero M, Pihlatie M, Janssens I, Yuste JC, Grünzweig JM, Reth S, Subke J-A, Savage K, Kutsch W, Østreng G, Ziegler W, Anthoni P, Lindroth A, Hari P (2004) Comparison of different chamber techniques for measuring soil CO2 efflux. Agric For Meteorol 123:159–176CrossRefGoogle Scholar