AN EXAMINATION OF THE SPECTRAL RESPONSE CHARACTERISTICS OF SEVEN ROBERTSON-BERGER METERS AFTER LONG-TERM FIELD USE

<p>Soil organic carbon (SOC) is of particular interest in the study of agricultural systems as an indicator of soil quality and soil fertility. In the use of Vis-NIR spectroscopy for SOC detection, the interpretation of the spectral response with regards to the importance of individual wavelengths is challenging due to the soil&#8217;s composition of multiple organic and minerals compounds. Under field conditions, additional aspects affect the spectral data compared to lab conditions. This study compared the spectral wavelength importance in partial least square regression (PLSR) models for SOC between field and lab conditions. Surface soil samples were obtained from a long-term field experiment (LTE) with high SOC variability located in the state of Saxony-Anhalt, Germany. Data sets of Vis-NIR spectra were acquired in the lab and field using two spectrometers, respectively. Four different preprocessing methods were applied before building the models. Wavelength importance was observed using variable importance in projection. Differences in wavelength importance were observed depending on the measurement device, measurement condition, and preprocessing technique, although pattern matches were identifiable, especially in the NIR range. It is these pattern matches that aid model interpretation to effectively determine SOC under field conditions.</p>

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Two-dimensional a-Si:H/a-SiC:H n-i-p sensor array with ITO/a-SiNx antireflection coating

MRS Proceedings ◽

10.1557/proc-862-a9.4 ◽

2005 ◽

Vol 862 ◽

Cited By ~ 2

Author(s):

Yu. Vygranenko ◽

J. H. Chang ◽

A. Nathan

Keyword(s):

Reverse Bias ◽

Spectral Response ◽

Charge Trapping ◽

Optical Excitation ◽

Antireflection Coating ◽

Two Dimensional ◽

Device Structure ◽

Response Characteristics ◽

Photodiode Array

AbstractThis paper presents a two-dimensional a–Si:H/a-SiC:H n–i–p photodiode array with switching diode readout, developed specifically for fluorescence-based bio-assays. Both device structure and fabrication processing has enabled enhancement of the external quantum efficiency of the encapsulated device up to 80%, reduction of the photodiode leakage down to 10 pA/cm2 at -1V reverse bias, and increase of the rectification current ratio of the switching diodes up to 109. The critical fabrication issues associated with deposition of device-quality materials, tailoring of defects at the i–p interface, device patterning with dry etching, junction passivation, and contact formation will be discussed. Both sensing and switching diodes were characterized. While the observed dark current in the photodiodes at low reverse bias voltages is primarily due to carrier emission from deep states in the a–Si:H bulk, the leakage in the small switching diodes stems from peripheral defects along junction sidewalls. Optical losses in the photodiodes with ITO/a–SiNx:H antireflection coating were evaluated using numerical modeling, and the calculated transmission spectra correlated well with the spectral response characteristics. Measurements of the charge transfer time and output linearity demonstrated the efficiency of the single-switching diode readout configuration. The response of the array to optical excitation was also investigated. The observed long term retardation in the signal rise and decay at illumination levels less than 1010 photons/cm2-s can be associated with charge trapping in the undoped layer.

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PLANNING LENGTH OF LONG -TERM FIELD EXPERIMENTS THROUGH DECISION SUPPORT SYSTEMS – A CASE STUDY

Applied Ecology and Environmental Research ◽

10.15666/aeer/0602_6378 ◽

2008 ◽

Vol 6 (2) ◽

pp. 63-78 ◽

Cited By ~ 3

Author(s):

R Kaur

Keyword(s):

Decision Support ◽

Decision Support Systems ◽

Field Experiments ◽

Support Systems ◽

Term Field

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DURUM WHEAT: RESULTS OF LONG-TERM FIELD RESEARCH ON THE DURUM WHEAT COLLECTION IN THE ENVIRONMENTS OF THE CASPIAN DEPRESSION

10.30901/978-5-905954-89-4 ◽

2018 ◽

Cited By ~ 1

Author(s):

O.A. Lyapunova ◽

◽

M.A. Akhmedov ◽

A.S. Andreeva ◽

M.M. Magomedov ◽

...

Keyword(s):

Durum Wheat ◽

Field Research ◽

Caspian Depression ◽

Term Field

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Long Term Field Test Results of Experimental EPDM and PUF Roofing

10.21236/ada226197 ◽

1990 ◽

Author(s):

David M. Bailey ◽

Stuart D. Foltz ◽

Myer J. Rosenfield

Keyword(s):

Field Test ◽

Test Results ◽

Term Field

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Critical plant phosphorus for winter wheat assessed from long-term field experiments

European Journal of Agronomy ◽

10.1016/j.eja.2021.126263 ◽

2021 ◽

Vol 126 ◽

pp. 126263

Author(s):

Mario Fontana ◽

Gilles Bélanger ◽

Juliane Hirte ◽

Noura Ziadi ◽

Saïd Elfouki ◽

...

Keyword(s):

Winter Wheat ◽

Field Experiments ◽

Term Field

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Long-term field fertilization experiment with energy willow (Salix sp.) − Elemental composition and chlorophyll fluorescence in the leaves

Agrokémia és Talajtan ◽

10.1556/0088.2018.67.1.7 ◽

2018 ◽

Vol 67 (1) ◽

pp. 91-103

Author(s):

László Simon ◽

Marianna Makádi ◽

György Vincze ◽

Zsuzsanna Uri ◽

Katalin Irinyiné Oláh ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Energy Crop ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Fertilization Experiment ◽

Nitrogen Concentrations ◽

Set Up ◽

Leaf Chlorophyll Fluorescence ◽

Term Field

A small-plot long-term field fertilization experiment was set up in 2011 with willow (Salix triandra x Salix viminalis ’Inger’) grown as an energy crop in Nyíregyháza, Hungary. The brown forest soil was treated three times (in June 2011, May 2013, May 2016) with municipal biocompost (MBC), municipal sewage sludge compost (MSSC) or willow ash (WA), and twice (June 2011, May 2013) with rhyolite tuff (RT). In late May – early June 2016 urea (U) and sulphuric urea (SU) fertilizers were also applied to the soil as top-dressing (TD). These fertilizers and amendments were also applied to the soil in 2016 in the combinations; MBC+SU, RT+SU, WA+SU and MSSC+WA. All the treatments were repeated four times. In July 2016 the highest nitrogen concentrations in willow leaves were measured in the U (3.47 m/m%) and SU (3.01 m/m%) treatments, and these values were significantly higher than the control (2.46 m/m%). An excess of nitrogen considerably reduced the Zn uptake of the leaves, with values of 39.5 μg g-1 in the U treatment, 53.4 μg g-1 in the SU treatment, and 63.5 μg g-1 in the control. All other amendments or TDs, except for WA, enhanced the specific potassium concentrations in willow leaves compared to the control. No significant quantities of toxic elements (As, Ba, Cd, Pb) were transported from soil amendments or TDs to the willow leaves. In July 2016 the most intensive leaf chlorophyll fluorescence was observed in the MSSC and MSSC+WA treatments.

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