Mid-infrared Diffuse Reflectance Spectroscopy for the Quantitative Analysis of Agricultural Soils

Abstract

Soil samples were analyzed conventionally and by mid-infrared diffuse reflectance spectroscopy for total C, total N, pH, and measures of biological activity. Ground, non KBr diluted, samples (n = 180) from experimental plots (two locations, three replicate plots, under plow and no-till practices, three rates of N fertilizer, and from five depths) were scanned from 4000 to 400 cm(-1) (4-cm(-1) resolution, 64 co-added scans) on a DigiLab FTS-60 Fourier transform spectrometer using a custom-made linear sample transport (50 by 2 mm sample area scanned). Results using partial least-squares regression showed that accurate calibrations can be developed for the determination of a number of compositional parameters: total C, total N, pH, and many measures of biological activity. In general, the results achieved using mid-infrared spectra were at least as accurate as those found previously using near-infrared spectra and were sometimes significantly better, that is, pH.

Chemical Differences in Soil Organic Matter Fractions Determined by Diffuse‐Reflectance Mid‐Infrared Spectroscopy

“…Fourier-transformed MidIR spectroscopy is a quick and nondestructive technology that has been used to calibrate for SOC in diverse sets of samples (McCarty and Reeves, 2000;Reeves et al, 2001;McCarty et al, 2002), indicating that the MidIR region contains spectral information related to a variety of soil chemical attributes. Th e MidIR region (4000-400 cm −1 ) is characterized by strong vibration fundamentals, and can be used for spectral interpretation of sample composition, because the MidIR spectra show peaks or bands that can be assigned to specifi c organic or mineral spectral bands (Nguyen et al, 1991;Haberhauer and Gerzabek, 1999;Baes and Bloom, 1989;Janik et al, 2007).…”

Big Sky Carbon Sequestration Partnership

“…However, it should be noted that there is little utility, for example, in using 117 samples from a single field to construct a model that can only be successfully applied to that same field 43 . A sample collected at 0-2.5 cm at one location is hardly independent of samples from the same location at 2.5-20 cm 44,45 . Demonstrating the lack of robustness for such models, NIR and MIR models calibrated using one field in Maryland performed poorly when used to predict C in another Maryland field 44,45 .…”

“…A sample collected at 0-2.5 cm at one location is hardly independent of samples from the same location at 2.5-20 cm 44,45 . Demonstrating the lack of robustness for such models, NIR and MIR models calibrated using one field in Maryland performed poorly when used to predict C in another Maryland field 44,45 . For a rolling field in Manitoba, even holding out 50% of the sample set at a time for cross-validation yielded a notably higher NIR RMSD value of 3.3 g OC kg -1 dry soil 46 .…”

“…45 The members raised $3 million that has resulted in the installation of 10 forestry projects designed to offset emissions or sequester carbon. The projects consist of a diverse mix of rural tree planting, forest preservation, forest management and research efforts at both domestic (Louisiana, Mississippi, Arkansas and Oregon) and 42 http://etr.defra.gov.uk/pdf/ETR_User_Manual.pdf 43 The UK Emissions trading registry website (http://etr.defra.gov.uk/default.asp) provides a user manual and other detailed guidance about opening the various accounts and engaging in the trading.…”

Determination of fat, protein and moisture in ricotta cheese by near infrared spectroscopy and multivariate calibration

“…Infrared spectroscopy provides a complete profile of the sample's composition, but it produces highly complex spectral signs and frequently has problems of nonlinearity between concentration and absorption intensity; therefore, it does not easily allow quantitative applications (Reeves et al 2001).…”