Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.soilbio.2021.108319
Document accepted manuscript
Title (Primary) VNIR and MIR spectroscopy of PLFA-derived soil microbial properties and associated physicochemical soil characteristics in an experimental plant diversity gradient
Author Hutengs, C.; Eisenhauer, N.; Schädler, M.; Lochner, A.; Seidel, M.; Vohland, M.
Journal Soil Biology & Biochemistry
Year 2021
Department BZF; iDiv
Volume 160
Page From art. 108319
Language englisch
Topic T5 Future Landscapes
Keywords proximal soil sensing; soil spectroscopy; portable instruments; microbial biomarkers; plant-soil interactions; bacterial and fungal biomass

Improving our understanding of the functions and processes of soil microbial communities and their interactions with the physicochemical soil environment requires large amounts of timely and cost-efficient soil data, which is difficult to obtain with routine laboratory-analytical methods. Soil spectroscopy with portable visible-to-near infrared (VNIR) and mid-infrared (MIR) instruments can fill this gap by facilitating the rapid acquisition of biotic and abiotic soil information.

In this study, we evaluated the capabilities of VNIR and MIR spectroscopy to analyze physicochemical and microbial soil properties in a long-term grassland biodiversity-ecosystem functioning experiment. Soil samples were collected at the Jena Experiment (Jena, Germany) and measured with portable VNIR and MIR spectrometers in field-moist condition to determine their potential for on-site data collection and analysis. Reference data to calibrate spectroscopic models were acquired with routine analytical methods, including PLFA extractions of microbial biomarkers. We further collected reference VNIR and MIR data on pre-treated soils (dried and finely ground) to assess the anticipated impact of field measurements on spectroscopic calibrations.

On pre-treated samples, MIR spectra allowed more accurate estimates of physicochemical and microbial soil properties than VNIR data. For soils in field condition, MIR calibrations were more accurate for physicochemical properties, but VNIR data gave significantly better estimates of microbial properties. Combined VNIR/MIR estimates achieved the most accurate estimation results for all soil properties in each case.

Physicochemical soil properties could be estimated from VNIR/MIR data with high accuracy (R2 = 0.72–0.99) on pre-treated soil samples, whereas results for microbial soil properties were more moderate (R2 = 0.66–0.72). On field-moist soils, estimation accuracies decreased notably for organic and inorganic carbon (ΔRMSE = 52–72%), improved slightly for soil texture (ΔRMSE = 4–7%) and decreased slightly for microbial properties (ΔRMSE = 4–9%). The VNIR/MIR estimates derived from soils in field condition were sufficiently accurate to detect experimental plant treatment effects on organic carbon, as well as bacterial and fungal biomass.

We further found that spectroscopic estimates of microbial soil properties were primarily enabled through indirect correlations with spectrally active soil constituents, i.e., associations between microbial soil properties and the physicochemical soil environment.

Our findings highlight the capacity of VNIR and MIR spectroscopy to analyze the physicochemical soil environment, including on-site data collection and analysis on soils in field condition, and indicate potential to estimate microbial soil properties through VNIR/MIR data when physicochemical soil properties shape the distribution of soil microbial communities.


Persistent UFZ Identifier
Hutengs, C., Eisenhauer, N., Schädler, M., Lochner, A., Seidel, M., Vohland, M. (2021):
VNIR and MIR spectroscopy of PLFA-derived soil microbial properties and associated physicochemical soil characteristics in an experimental plant diversity gradient
Soil Biol. Biochem. 160 , art. 108319