Evaluation of three field-based methods for quantifying soil carbon.

Three advanced technologies to measure soil carbon (C) density (g C m(-2)) are deployed in the field and the results compared against those obtained by the dry combustion (DC) method. The advanced methods are: a) Laser Induced Breakdown Spectroscopy (LIBS), b) Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS), and c) Inelastic Neutron Scattering (INS). The measurements and soil samples were acquired at Beltsville, MD, USA and at Centro International para el Mejoramiento del Maíz y el Trigo (CIMMYT) at El Batán, Mexico.

Mid-infrared spectroscopy of biochars and spectral similarities to coal and kerogens: what are the implications?

Biochar is the solid residue produced by the pyrolysis of any bio-organic material under low, or no, oxygen conditions and has generated considerable interest as a means to sequester carbon in, and improve the quality of, soils. However, the exact properties of biochar depend on its composition, which in turn depends on the composition of the starting material and the temperature and conditions under which the biochar is produced. Mid-infrared spectroscopy offers an excellent and rapid method for characterizing both the starting materials and the resulting biochar.

Use of mid- and near-infrared spectroscopy to track degradation of bio-based eating utensils during composting.

Near-infrared spectroscopy (NIRS) and mid-infrared spectroscopy (MIRS) have been used for quantitative and/or qualitative analysis of a wide range of materials. The objective of this study was to investigate the potential of MIRS and NIRS for following the degradation of bio-based food utensils during composting. Polylactide (PLA)-based forks lost 34% of their initial mass and were reduced to small friable fragments after 7 weeks of composting.

A graphical method to evaluate spectral preprocessing in multivariate regression calibrations: example with Savitzky-Golay filters and partial least squares regression.

In multivariate regression analysis of spectroscopy data, spectral preprocessing is often performed to reduce unwanted background information (offsets, sloped baselines) or accentuate absorption features in intrinsically overlapping bands. These procedures, also known as pretreatments, are commonly smoothing operations or derivatives. While such operations are often useful in reducing the number of latent variables of the actual decomposition and lowering residual error, they also run the risk of misleading the practitioner into accepting calibration equations that are poorly adapted to samples outside of the calibration.

Does the spectral format matter in diffuse reflection spectroscopy?

Near-infrared, and more recently, mid-infrared diffuse reflection spectroscopy (more commonly and erroneously called reflectance spectroscopy) have come to be extensively used to determine the composition of products ranging from forages and drugs to soils. In these methods, spectra are generally collected as reflectance or R and transformed to log (1/reflectance). However, some near-infrared researchers do not transform the data, but use the data directly as reflectance.

Mid-Infrared and near-infrared spectral properties of mycorrhizal and non-mycorrhizal root cultures.

We investigated the Fourier-transformed mid-infrared (MIR) and near-infrared (NIR) spectroscopic properties of mycorrhizal (M) and non-mycorrhizal (NM) carrot roots with the goal of finding infrared markers for colonization by arbuscular mycorrhizal (AM) fungi. The roots were cultured with or without the AM fungus Glomus intraradices under laboratory conditions. A total of 50 M and NM samples were produced after pooling subsamples.

Mid-infrared and near-infrared calibrations for nutritional parameters of Triticale (Triticosecale) and pea (Pisum sativum).

The objective of this study was to develop Fourier transformed mid-infrared (MidIR) and near-infrared (NIR) calibrations for acid detergent fiber (ADF), neutral detergent fiber (NDF), and total nitrogen in triticale, peas, and triticale/pea mixtures. Heterogeneous calibration-validation combinations were also tested for calibration quality. The forage samples were collected from forage plots grown following millet or wheat.

Mid-infrared diffuse reflectance spectroscopic examination of charred pine wood, bark, cellulose, and lignin: implications for the quantitative determination of charcoal in soils.

Fires in terrestrial ecosystems produce large amounts of charcoal that persist in the environment and represent a substantial pool of sequestered carbon in soil. The objective of this research was to investigate the effect of charring on mid-infrared spectra of materials likely to be present in forest fires in order to determine the feasibility of determining charred organic matter in soils. Four materials (cellulose, lignin, pine bark, and pine wood) and char from these materials, created by charring for various durations (1 to 168 h) and at various temperatures (200 to 450 degrees C), were studied.

Comparison of diffuse reflectance fourier transform mid-infrared and near-infrared spectroscopy with grating-based near-infrared for the determination of fatty acids in forages.

Diffuse reflectance Fourier transform mid infrared (FTMIR) and near-infrared spectroscopy (FTNIR) were compared to scanning monochromator-grating-based near-infrared spectroscopy (SMNIR), for their ability to quantify fatty acids (FA) in forages. A total of 182 samples from thirteen different forage cultivars and three different harvest times were analyzed. Three calibration analyses were conducted for lauric (C12:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0), palmitoleic (C16:1), oleic (C18:1), linoleic (C18:2), and alpha-linolenic (C18:3) acids.

Stearic acid solubility and cubic phase volume.

Stearic acid (SA) is highly soluble in structurally diverse solvents. SA/solvent packing within a (24.8 A)3 cubic volume explains the stoichiometry of SA solubility at multiple temperatures in multiple solvents.

Pyrolysis of foundry sand resins: a determination of organic products by mass spectrometry.

Pyrolysis-gas chromatography-mass spectrometry (MS) was used to identify the major organic products produced by pyrolysis of three foundry sand resins: (i) Novolac and (ii) phenolic urethane (PU) (both phenol-formaldehyde based resins) and (iii) furan (furfuryl alcohol based resin). These resins are used in the metal casting industry as a "sand binder" for making cores (used to produce cavities in molds) and molds for nonferrous castings. During the casting process, the cores and molds are subjected to intense heat from the molten metal.

Specular reflection and diffuse reflectance spectroscopy of soils.

Studies on the occurrence and effects of specular reflection in midinfrared spectra of soils have shown that distortions due to specular reflection occur for both organic (humic acid) and non-organic fractions (carbonates, silica, ashed fraction of soil). The results explain why the spectra of CaCO(3) in limed soils do not match published spectra and offer an explanation as to why the presence of inorganic C interferes with the development of calibrations for organic C. These results may also have implications for the use of mid-infrared spectra for quantitative and qualitative analysis of soils.

Near- and mid-infrared diffuse reflectance spectroscopy for measuring soil metal content.

Rapid and nondestructive methods such as diffuse reflectance infrared spectroscopy provide potentially useful alternatives to time-consuming chemical methods of soil metal analysis. To assess the utility of near-infrared reflectance spectroscopy (NIRS) and diffuse mid-infrared reflectance spectroscopy (DRIFTS) for soil metal determination, 70 soil samples from the metal mining region of Tarnowskie Gory (Upper Silesia, Poland) were analyzed by both chemical and spectroscopic methods. Soils represented a wide range of pH (4.

Influence of ash on the fiber composition of dried dairy manures.

The objective of this work was to examine the role of ash in the compositional analysis of dried dairy manures. Ninety-nine dairy manures obtained from Connecticut, Maryland, New York, Pennsylvania and Virginia were dried at 60 degrees C, and ground to 20 mesh. Samples were analyzed for neutral and acid detergent fiber, acid detergent lignin, total carbon, total nitrogen, and ash.