scholarly journals Chemical and Spectroscopic Investigation of Different Soil Fractions as Affected by Soil Management

2020 ◽  
Vol 10 (7) ◽  
pp. 2571 ◽  
Author(s):  
Francesco De Mastro ◽  
Claudio Cocozza ◽  
Gennaro Brunetti ◽  
Andreina Traversa
Keyword(s):  
Diffuse Reflectance ◽  
Soil Depth ◽  
Soil Layer ◽  
Mineralogical Composition ◽  
Coarse Fraction ◽  
Soil Fractions ◽  
Soil Fraction ◽  
Drift Analysis ◽  
Diffuse Reflectance Infrared ◽  
Conventional Ct

The interaction of organic matter with the finest soil fractions (<20 μm) represents a good way for its stabilization. This study investigates the effects of conventional (CT), minimum (MT), and no (NT) tillage, fertilization, and non-fertilization, and soil depth (0–30, 30–60, and 60–90 cm) on the amount of organic carbon (OC) in four soil fractions. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) was performed to obtain information about the OC quality and the mineralogical composition of these fractions. The CT shows the highest amount of the finest fraction while the fertilization enhances the microbial community with the increase of soil micro-aggregates (250–53 μm). The coarse fraction (>250 μm) is highest in the upper soil layer, while the finest fraction is in the deepest one. The greatest OC content is observed in the topsoil layer and in the finest soil fraction. DRIFT analysis suggests that organic components are more present in the finest fraction, calcite is mainly localized in the coarse fraction, quartz is in micro-aggregates and 53–20 μm fraction, and clay minerals are in the finest fraction.

scholarly journals Vertical Distribution of the Plant-Parasitic Nematode, Pratylenchus penetrans, Under Four Field Crops

2006 ◽  
Vol 96 (3) ◽  
pp. 226-233 ◽  
Author(s):  
Mahesh P. Pudasaini ◽  
Cornelia H. Schomaker ◽  
Thomas H. Been ◽  
Maurice Moens
Keyword(s):  
Vertical Distribution ◽  
Sampling Error ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Layer ◽  
Reliable Estimate ◽  
Pratylenchus Penetrans ◽  
Sampling Depth ◽  
Soil Fraction ◽  
Optimum Sampling

The vertical distribution of Pratylenchus penetrans was monitored in four fields cropped with maize, black salsify, carrot, or potato. Soil samples were collected at 21-day intervals from May 2002 until April 2003 from five plots (2 × 5 m2) per field. Per plot, 15 cores were taken to a depth of 70 cm and split into seven segments of 10 cm each. Within the plots, segments from corresponding depths were pooled. After mixing, 200-g subsamples were taken and nematodes were extracted by zonal centrifugation from the root fraction and the mineral soil fraction separately. In most crops, the root fraction contained more than 50% of the total number of P. penetrans. Because the ratio between the numbers of nematodes in the root fraction and mineral soil fraction changes during the growing season, numbers of P. penetrans found in the mineral soil fraction cannot be used to estimate the total number in the soil. Therefore, both fractions have to be processed to obtain a reliable estimate of the density. No nematodes were recovered below 50 cm soil depth, except in the maize field where nematodes were found at 70 cm. The optimum sampling depth for maize, black salsify, carrot, and potato was 45, 25, 25, and 35 cm, respectively. The percentage of nematodes per soil layer was independent of the sampling date, indicating that a defined optimum sampling depth will be applicable throughout all seasons. The cumulative vertical distribution, modeled with a logistic equation, can be used to estimate the sampling error when samples are collected at different depths.

scholarly journals Soil Organic Carbon Stabilization: Influence of Tillage on Mineralogical and Chemical Parameters

Soil Systems ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 58 ◽  
Author(s):  
Francesco De Mastro ◽  
Andreina Traversa ◽  
Claudio Cocozza ◽  
Mauro Pallara ◽  
Gennaro Brunetti
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Clay Minerals ◽  
Near Infrared ◽  
Soil Depth ◽  
Mineralogical Composition ◽  
Amorphous Oxides ◽  
Size Fractions ◽  
X Ray ◽  
Soil Fractions

The interaction of organic carbon (OC) with clay minerals and amorphous iron and aluminum oxides, especially in the finest soil fractions (<20 μm), represents a good method for its stabilization, and different tillage practices can improve or reduce the persistence of OC in soils. This study investigates the effects of conventional (CT) and no (NT) tillage and soil depth (0–30, 30–60, and 60–90 cm) on the soil organic carbon (SOC) in four soil size fractions and its interactions with clay minerals and amorphous oxides. To identify the mineralogical composition of the four soil size fractions isolated from each soil, the X-ray powder diffraction (XRPD) technique was used with near infrared (NIR) spectroscopy, while the X-ray fluorescence (XRF) technique was used to determine the chemical composition of soil fractions. The higher OC content found in the finest soil fraction is related to its higher content of clay minerals and amorphous oxides. The SOC content is similar among CT and NT treatments as well as the mineralogical composition and the amount of amorphous oxides, suggesting that more than ten years of different tillage did not influence those parameters.

scholarly journals Changes of Pd Oxidation State in Pd/Al2O3 Catalysts Using Modulated Excitation DRIFTS

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 116
Author(s):  
Gian Luca Chiarello ◽  
Ye Lu ◽  
Miren Agote-Arán ◽  
Riccardo Pellegrini ◽  
Davide Ferri
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Oxidation State ◽  
Diffuse Reflectance ◽  
X Ray ◽  
Spectral Changes ◽  
Diffuse Reflectance Infrared ◽  
X Ray Absorption ◽  
Reversible Reduction

Infrared spectroscopy is typically not used to establish the oxidation state of metal-based catalysts. In this work, we show that the baseline of spectra collected in diffuse reflectance mode of a series of Pd/Al2O3 samples of increasing Pd content varies significantly and reversibly under alternate pulses of CO or H2 and O2. Moreover, these baseline changes are proportional to the Pd content in Pd/Al2O3 samples exhibiting comparable Pd particle size. Similar measurements by X-ray absorption spectroscopy on a different 2 wt.% Pd/Al2O3 confirm that the baseline changes reflect the reversible reduction-oxidation of Pd. Hence, we demonstrate that changes in oxidation state of metal-based catalysts can be determined using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and that this behavior is part of the spectral changes that are returned by experiments under operando conditions.

Figures of Merit for a Diffuse Reflectance Accessory Using an On-Axis Ellipsoidal Collecting Mirror

1988 ◽  
Vol 42 (3) ◽  
pp. 428-433 ◽  
Author(s):  
E. H. Korte
Keyword(s):  
Infrared Spectroscopy ◽  
Noise Level ◽  
Diffuse Reflectance ◽  
Field Of View ◽  
Figures Of Merit ◽  
Size Dependent ◽  
Diffuse Reflectance Infrared Spectroscopy ◽  
Diffuse Reflectance Infrared

The attainable efficiency of an accessory for diffuse reflectance infrared spectroscopy where both the irradiation and detection optics are located on the same side of the sample is analyzed, the size-dependent noise level of the detector being taken into account. The resulting figures of merit are found to reach up to more than 0.3, when standard detectors of 60° field-of-view are considered.

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