{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T07:25:45Z","timestamp":1772177145983,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,3,27]],"date-time":"2018-03-27T00:00:00Z","timestamp":1522108800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Mid-infrared (MIR) spectroscopy has received widespread interest as a method to complement traditional soil analysis. Recently available portable MIR spectrometers additionally offer potential for on-site applications, given sufficient spectral data quality. We therefore tested the performance of the Agilent 4300 Handheld FTIR (DRIFT spectra) in comparison to a Bruker Tensor 27 bench-top instrument in terms of (i) spectral quality and measurement noise quantified by wavelet analysis; (ii) accuracy of partial least squares (PLS) calibrations for soil organic carbon (SOC), total nitrogen (N), pH, clay and sand content with a repeated cross-validation analysis; and (iii) key spectral regions for these soil properties identified with a Monte Carlo spectral variable selection approach. Measurements and multivariate calibrations with the handheld device were as good as or slightly better than Bruker equipped with a DRIFT accessory, but not as accurate as with directional hemispherical reflectance (DHR) data collected with an integrating sphere. Variations in noise did not markedly affect the accuracy of multivariate PLS calibrations. Identified key spectral regions for PLS calibrations provided a good match between Agilent and Bruker DHR data, especially for SOC and N. Our findings suggest that portable FTIR instruments are a viable alternative for MIR measurements in the laboratory and offer great potential for on-site applications.<\/jats:p>","DOI":"10.3390\/s18040993","type":"journal-article","created":{"date-parts":[[2018,3,27]],"date-time":"2018-03-27T12:17:24Z","timestamp":1522153044000},"page":"993","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":64,"title":["Comparison of Portable and Bench-Top Spectrometers for Mid-Infrared Diffuse Reflectance Measurements of Soils"],"prefix":"10.3390","volume":"18","author":[{"given":"Christopher","family":"Hutengs","sequence":"first","affiliation":[{"name":"Geoinformatics and Remote Sensing, Institute for Geography, Leipzig University, Johannisallee 19a, 04103 Leipzig, Germany"},{"name":"German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany"}]},{"given":"Bernard","family":"Ludwig","sequence":"additional","affiliation":[{"name":"Deparatment of Environmental Chemistry, Kassel University, Nordbahnhofstr. 1a, 37213 Witzenhausen, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3250-4097","authenticated-orcid":false,"given":"Andr\u00e1s","family":"Jung","sequence":"additional","affiliation":[{"name":"Technical Department, Szent Istv\u00e1n University, Vill\u00e1nyi \u00fat 29-43, 1118 Budapest, Hungary"}]},{"given":"Andreas","family":"Eisele","sequence":"additional","affiliation":[{"name":"SphereOptics GmbH, Gewerbestrasse 13, 82211 Herrsching, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6048-1163","authenticated-orcid":false,"given":"Michael","family":"Vohland","sequence":"additional","affiliation":[{"name":"Geoinformatics and Remote Sensing, Institute for Geography, Leipzig University, Johannisallee 19a, 04103 Leipzig, Germany"},{"name":"German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1398","DOI":"10.1016\/j.soilbio.2011.02.019","article-title":"Near-infrared (NIR) and mid-infrared (MIR) spectroscopic techniques for assessing the amount of carbon stock in soils\u2014Critical review and research perspectives","volume":"43","author":"McBratney","year":"2011","journal-title":"Soil Biol. Biochem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/S0065-2113(10)07005-7","article-title":"Visible and near nnfrared spectroscopy in soil science","volume":"Volume 107","author":"Sparks","year":"2010","journal-title":"Advances in Agronomy"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1016\/bs.agron.2015.02.002","article-title":"Soil spectroscopy: An alternative to wet chemistry for soil monitoring","volume":"Volume 132","author":"Sparks","year":"2015","journal-title":"Advances in Agronomy"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.geoderma.2005.03.007","article-title":"Visible, near infrared, mid infrared or combined diffuse reflectance spectroscopy for simultaneous assessment of various soil properties","volume":"131","author":"Walvoort","year":"2006","journal-title":"Geoderma"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1080\/05704928.2013.811081","article-title":"The performance of visible, near-, and mid-infrared reflectance spectroscopy for prediction of soil physical, chemical, and biological properties","volume":"49","author":"Janik","year":"2014","journal-title":"Appl. Spectrosc. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1016\/j.geoderma.2009.12.025","article-title":"Using data mining to model and interpret soil diffuse reflectance spectra","volume":"158","author":"Behrens","year":"2010","journal-title":"Geoderma"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.geoderma.2011.08.001","article-title":"Comparing different multivariate calibration methods for the determination of soil organic carbon pools with visible to near infrared spectroscopy","volume":"166","author":"Vohland","year":"2011","journal-title":"Geoderma"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1016\/j.jhazmat.2013.11.059","article-title":"Visible and near-infrared reflectance spectroscopy\u2014An alternative for monitoring soil contamination by heavy metals","volume":"265","author":"Shi","year":"2014","journal-title":"J. Hazardous Mater."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"988","DOI":"10.2136\/sssaj2002.9880","article-title":"Development of reflectance spectra libraries for characterization of soil properties","volume":"66","author":"Shepherd","year":"2002","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.geoderma.2010.03.001","article-title":"Comparison among principal component, partial least squares and back propagation neural network analyses for accuracy of measurement of selected soil properties with visible and near infrared spectroscopy","volume":"158","author":"Mouazen","year":"2010","journal-title":"Geoderma"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1016\/j.geoderma.2007.12.009","article-title":"Laboratory, field and airborne spectroscopy for monitoring organic carbon content in agricultural soils","volume":"144","author":"Stevens","year":"2008","journal-title":"Geoderma"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/j.geoderma.2014.10.019","article-title":"Modelling soil carbon fractions with visible near-infrared (VNIR) and mid-infrared (MIR) spectroscopy","volume":"239","author":"Knox","year":"2015","journal-title":"Geoderma"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Izaurralde, R.C., Rice, C.W., Wielopolski, L., Ebinger, M.H., Reeves III, J.B., Thomson, A.M., Harris, R., Francis, B., Mitra, S., and Rappaport, A.G. (2013). Evaluation of three field-based methods for quantifying soil carbon. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0055560"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1071\/SR14126","article-title":"Use of handheld mid-infrared spectroscopy and partial least-squares regression for the prediction of the phosphorus buffering index in Australian Soils","volume":"53","author":"Forrester","year":"2015","journal-title":"Soil Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.biosystemseng.2016.06.005","article-title":"Assessment of soil properties in situ using a prototype portable MIR spectrometer in two agricultural fields","volume":"152","author":"Ji","year":"2016","journal-title":"Biosyst. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Viscarra Rossel, R.A., McBratney, A.B., and Minasny, B. (2010). Mid-versus near-infrared spectroscopy for on-site analysis of soil. Proximal Soil Sensing: Progress in Soil Science, Springer-Verlag.","DOI":"10.1007\/978-90-481-8859-8"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"215","DOI":"10.2516\/ogst:2004016","article-title":"Diffuse reflection infrared spectroscopy (DRIFTS): Application to the in situ Analysis of catalysts","volume":"59","author":"Armaroli","year":"2004","journal-title":"Oil Gas Sci. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.biosystemseng.2017.06.017","article-title":"Evaluation of the performance of portable visible-infrared instruments for the prediction of soil properties","volume":"161","author":"Janik","year":"2017","journal-title":"Biosyst. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1016\/j.earscirev.2010.07.005","article-title":"Thermal infrared spectroscopy on feldspars\u2014Successes, limitations and their implications for remote sensing","volume":"103","author":"Hecker","year":"2010","journal-title":"Earth Sci. Rev."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1016\/j.geoderma.2016.01.010","article-title":"Pitfalls in the use of middle-infrared spectroscopy: Respresentativeness and ranking criteria for the estimation of soil properties","volume":"268","author":"Ludwig","year":"2016","journal-title":"Geoderma"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4011","DOI":"10.1109\/JSTARS.2016.2572879","article-title":"Quantification of soil variables in a heterogeneous soil region with VIS-NIR-SWIR data using different statistical sampling and modelling strategies","volume":"9","author":"Vohland","year":"2016","journal-title":"IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"11434","DOI":"10.3390\/rs70911434","article-title":"Use of a portable camera for proximal soil sensing with hyperspectral image data","volume":"7","author":"Jung","year":"2015","journal-title":"Remote Sens."},{"key":"ref_23","unstructured":"Food and Agriculture Organization (FAO) (2006). Guidelines for Soil Description, FAO. [4th ed.]."},{"key":"ref_24","unstructured":"International Organization for Standardization (ISO) (1994). Soil Quality; Determination of Particle Size Distribution in Mineral Soil Material; Method by Sieving and Sedimentation Following Removal of Soluble Salts, Organic Matter and Carbonates, German Institute for Standardization (EDIN). ISO 11277:06.94, 1994."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Moler, C.B. (2004). Interpolation. Numerical Computing with MATLAB, Society for Industrial and Applied Mathematics (SIAM).","DOI":"10.1137\/1.9780898717952"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2059","DOI":"10.1093\/bioinformatics\/btl355","article-title":"Improved peak detection in mass spectrum by incorporating continuous wavelet transform-based pattern matching","volume":"22","author":"Du","year":"2006","journal-title":"Bioinformatics"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1255\/jnirs.1233","article-title":"Using variable selection and wavelets to exploit the full potential of visible\u2013near infrared spectra for predicting soil properties","volume":"24","author":"Vohland","year":"2016","journal-title":"J. Near Infrared Spec."},{"key":"ref_28","unstructured":"Petrov, B.N., and Cs\u00e1ki, F. (1973). Information theory and an extension of maximum likelihood principle. Second International Symposiumon Information Theory, Akad\u00e9mia Kiad\u00f3."},{"key":"ref_29","first-page":"e190v1","article-title":"lilPLS: An integrated library for partial least squares regression and discriminant analysis","volume":"2","author":"Li","year":"2014","journal-title":"PeerJ PrePrints"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.aca.2009.06.046","article-title":"Key wavelengths screening using competitive adaptive reweighted sampling method for multivariate calibration","volume":"648","author":"Li","year":"2009","journal-title":"Anal. Chim. Acta"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/B978-0-12-800132-5.00001-8","article-title":"Soil chemical insights provided through vibrational spectroscopy","volume":"Volume 126","author":"Sparks","year":"2014","journal-title":"Advances in Agronomy"},{"key":"ref_32","first-page":"2327","article-title":"Mid-Infrared Spectroscopy: Anomalies, Artifacts and Common Errors","volume":"Volume 3","author":"Chalmers","year":"2002","journal-title":"Handbook of Vibrational Spectroscopy"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1016\/j.geoderma.2012.06.008","article-title":"Mid-infrared spectral interpretation of soils: Is it practical or accurate?","volume":"189\u2013190","author":"Reeves","year":"2012","journal-title":"Geoderma"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1071\/SR9910049","article-title":"Diffuse reflectance infrared Fourier-Transform (DRIFT) spectroscopy in soil studies","volume":"29","author":"Nguyen","year":"1991","journal-title":"Aust. J. Soil Res."},{"key":"ref_35","first-page":"E03004","article-title":"Emission spectroscopy of clay minerals and evidence for poorly crystalline aluminosilicates on Mars from Thermal Emission Spectrometer data","volume":"111","author":"Michalski","year":"2006","journal-title":"J. Geophys. Res."},{"key":"ref_36","first-page":"283","article-title":"Visible and near-infrared spectra of minerals and rocks. I. Silicate minerals","volume":"1","author":"Hunt","year":"1970","journal-title":"Mod. Geol."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Farmer, V.C. (1974). The Layer Silicates. The Infrared Spectra of Minerals, Mineralogical Soc.","DOI":"10.1180\/mono-4"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1016\/j.rse.2015.04.001","article-title":"Advantages using the thermal infrared (TIR) to detect and quantify semi-arid soil properties","volume":"163","author":"Eisele","year":"2015","journal-title":"Remote Sens. Environ."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"568","DOI":"10.2136\/sssaj2009.0375","article-title":"Chemical differences in soil organic matter fractions determined by diffuse-reflectance mid-infrared spectroscopy","volume":"75","author":"Reeves","year":"2011","journal-title":"Soil Sci. Soc. Am. J."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.geoderma.2014.01.013","article-title":"Determination of soil properties with visible to near- and mid-infrared spectroscopy: Effects of spectral variable selection","volume":"223\u2013225","author":"Vohland","year":"2014","journal-title":"Geoderma"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"192","DOI":"10.17221\/317\/2011-PSE","article-title":"Application of FTIR spectroscopy for evaluation of hydrophobic\/hydrophilic organic components in arable soil","volume":"58","author":"Matejkova","year":"2012","journal-title":"Plant Soil Environ."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/993\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:58:40Z","timestamp":1760194720000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/4\/993"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,3,27]]},"references-count":41,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2018,4]]}},"alternative-id":["s18040993"],"URL":"https:\/\/doi.org\/10.3390\/s18040993","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,3,27]]}}}