Measuring soil organic carbon: which technique and where to from here?

Soil Research ◽  
2015 ◽  
Vol 53 (7) ◽  
pp. 717 ◽  
Author(s):  
Timothy J. Johns ◽  
Michael J. Angove ◽  
Sabine Wilkens
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Time Budget ◽  
Analytical Techniques ◽  
Wet Oxidation ◽  
Spectroscopic Techniques ◽  
Research Needs ◽  
Important Health ◽  
Definition Of ◽  
Selection Of

This review compares and contrasts analytical techniques for the measurement of total soil organic carbon (TOC). Soil TOC is seen to be a highly important health and quality indicator for soils, as well as having the potential to sequester atmospheric carbon. Definition of the form of organic carbon measured by a given method is vital to the selection of appropriate methodology, as well as the understanding of what exactly is being measured. Historically, studies of TOC have ranged from basic measures, such as colour and gravimetric analyses, to dry and wet oxidation techniques. In more recent times, various spectroscopic techniques and the application of remote or mobile approaches have gained prominence. The different techniques, even the oldest ones, may have their place in current research depending on research needs, the available time, budget and access to wider resources. This review provides an overview of the various methods, highlights advantages, limitations and research opportunities and provides an indication of what the method actually measures so that meaningful comparisons can be made.

scholarly journals Influence of the Selection of Interpolation Method on Revealing Soil Organic Carbon Variability in the Red Soil Region, China

2018 ◽  
Vol 10 (7) ◽  
pp. 2290 ◽  
Author(s):  
Zhongqi Zhang ◽  
Dongsheng Yu ◽  
Xiyang Wang ◽  
Yue Pan ◽  
Guangxing Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Interpolation Method ◽  
Red Soil ◽  
Selection Of

scholarly journals Ensemble Identification of Spectral Bands Related to Soil Organic Carbon Levels over an Agricultural Field in Southern Ontario, Canada

2019 ◽  
Vol 11 (11) ◽  
pp. 1298 ◽  
Author(s):  
Ahmed Laamrani ◽  
Aaron A. Berg ◽  
Paul Voroney ◽  
Hannes Feilhauer ◽  
Line Blackburn ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Near Infrared ◽  
Hyperspectral Data ◽  
Support Vector ◽  
Least Squares Regression ◽  
Agricultural Field ◽  
Southern Ontario ◽  
Spectral Bands ◽  
Selection Of

The recent use of hyperspectral remote sensing imagery has introduced new opportunities for soil organic carbon (SOC) assessment and monitoring. These data enable monitoring of a wide variety of soil properties but pose important methodological challenges. Highly correlated hyperspectral spectral bands can affect the prediction and accuracy as well as the interpretability of the retrieval model. Therefore, the spectral dimension needs to be reduced through a selection of specific spectral bands or regions that are most helpful to describing SOC. This study evaluates the efficiency of visible near-infrared (VNIR) and shortwave near-infrared (SWIR) hyperspectral data to identify the most informative hyperspectral bands responding to SOC content in agricultural soils. Soil samples (111) were collected over an agricultural field in southern Ontario, Canada and analyzed against two hyperspectral datasets: An airborne Nano-Hyperspec imaging sensor with 270 bands (400–1000 nm) and a laboratory hyperspectral dataset (ASD FieldSpec 3) along the 1000–2500 nm range (NIR-SWIR). In parallel, a multimethod modeling approach consisting of random forest, support vector machine, and partial least squares regression models was used to conduct band selections and to assess the validity of the selected bands. The multimethod model resulted in a selection of optimal band or regions over the VNIR and SWIR sensitive to SOC and potentially for mapping. The bands that achieved the highest respective importance values were 711–715, 727, 986–998, and 433–435 nm regions (VNIR); and 2365–2373, 2481–2500, and 2198–2206 nm (NIR-SWIR). Some of these bands are in agreement with the absorption features of SOC reported in the literature, whereas others have not been reported before. Ultimately, the selection of optimal band and regions is of importance for quantification of agricultural SOC and would provide a new framework for creating optimized SOC-specific sensors.

Selection of terrain attributes and its scale dependency on soil organic carbon prediction

Geoderma ◽  
2019 ◽  
Vol 340 ◽  
pp. 303-312 ◽  
Author(s):  
Zhixing Guo ◽  
Kabindra Adhikari ◽  
Menaka Chellasamy ◽  
Mette B. Greve ◽  
Phillip R. Owens ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Scale Dependency ◽  
Terrain Attributes ◽  
Selection Of

scholarly journals Spatial distribution of soil organic carbon by digital mapping: the case of the Medio Aguanaval river sub-basin

2021 ◽  
Vol 13 (2) ◽  
pp. 227-245
Author(s):  
Georgina Pérez-Rodríguez ◽  
◽  
Armando López-Santos ◽  
Miguel Agustín Velásquez-Valle ◽  
José Villanueva-Díaz ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Horizontal Distribution ◽  
Digital Mapping ◽  
Lack Of Information ◽  
Static Modeling ◽  
Vertical And Horizontal Distribution ◽  
Soc Stocks ◽  
Selection Of

ntroduction: Carbon is found mainly in geological reservoirs, oceans, atmosphere and land. Soil organic carbon (SOC) is determined by the quantity and vertical distribution of vegetation, intrinsic soil properties and climate, but variability is influenced by anthropogenic interference. SOC stocks are not static; modeling their spatial, vertical and horizontal distribution involves the creation of baseline estimates to quantify these stocks. Objective: To estimate the magnitude of SOC stocks in the Medio Aguanaval River sub-basin (ScRMA) and to analyze the sensitivity of four interpolation methods to minimize the error of digital mapping for the ScRMA. Methodology: The study consisted of five stages: 1) search, download and analysis of soil data, 2) data processing, 3) selection of verification sites, 4) laboratory analysis and 5) processing of data from verification sites. Results: SOC values ranged from 9 to 133 t·ha-1, with a mean of 36.31 t·ha-1 and standard deviation of 23.83 t·ha-1. The ordinary exponential Kriging interpolator was the best representation for SOC of the ScRMA based onstatistics. The results of the analysis of the verification sites yielded a mean SOC of 24.4 t·ha-1. Limitations of the study: Soil profile density for the region and the lack of information on bulk density. Originality: The baseline distribution of SOC at the sub-basin level was used to analyze its dynamics. Conclusions: The highest concentration of SOC (61 to 129 t·ha-1) was found in the municipalities of Cuencamé and Santa Clara, while the lowest records (10 to 30 t·ha-1) were located in the municipalities of Torreón and Viesca.

Onderwijs Nederlands als Tweede Taal aan Volwassenen

1985 ◽  
Vol 22 ◽  
pp. 107-128
Author(s):  
Guus Extra
Keyword(s):  
Public Policy ◽  
Second Language ◽  
Language Proficiency ◽  
Research Needs ◽  
Second Language Proficiency ◽  
Research Themes ◽  
In Series ◽  
Language Needs ◽  
Definition Of ◽  
Selection Of

In this text five focal areas for teaching Dutch as a second language to adults are discussed. The first two areas derive from a didactic cycle that calls for a discussion in series: insights into language needs are necessary - although insufficient - prerequisites for defining and choosing educational objectives. In turn, only operationalized educational object-ives make it possible to select and grade course contents at the level of words, utterances and texts. Both the definition of language needs and educational object-ives (§1), and the selection and gradation of course contents (§2) are necessary pre-activities for our third perspective: the development and use of textbooks and tests (§3). For using textbooks, too we need a discussion in series, running from registration, description, and evaluation to selection of text-books. In our section on developmental activities, we also pay attention to different tests for measuring second language proficiency of adults. Research needs are our fourth focal area for teaching L2 Dutch to adults (§4). In this section we go into several research themes and into their relevance for L2 teaching. Our last perspective derives from public policy with respect to L2 Dutch (§5). We focus on existing government provisions and conditions, and on main policy plans with respect to teaching Dutch as a second language to adults.

scholarly journals Evaluation of structural chemistry and isotopic signatures of refractory soil organic carbon fraction isolated by wet oxidation methods

2009 ◽  
Vol 98 (1-3) ◽  
pp. 29-44 ◽  
Author(s):  
Sindhu Jagadamma ◽  
Rattan Lal ◽  
David A. N. Ussiri ◽  
Susan E. Trumbore ◽  
Silvia Mestelan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Structural Chemistry ◽  
Wet Oxidation ◽  
Carbon Fraction ◽  
Isotopic Signatures

Soil Organic Carbon: Relating the Walkley-Black Wet Oxidation Method to Loss on Ignition and Clay Content

2014 ◽  
Vol 2 (5) ◽  
pp. 249-256
Author(s):  
Henry Oppong Tuffour ◽  
Israel Boateng Yeboah ◽  
Mensah Bonsu ◽  
Thomas Adjei-Gyapong ◽  
Abdul Aziz Khalid ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Clay Content ◽  
Wet Oxidation ◽  
Loss On Ignition ◽  
Oxidation Method

Selection and Preparation of Specific Tissue Regions For Tem Using Large Epoxy-Embedded Blocks

1973 ◽  
Vol 31 ◽  
pp. 324-325 ◽  
Author(s):  
P. M. Lowrie ◽  
W. S. Tyler
Keyword(s):  
Electron Microscopy ◽  
Anatomical Structures ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Microscopic Evaluation ◽  
Embedded Blocks ◽  
Specific Tissue ◽  
Definition Of ◽  
Areas Of Interest ◽  
Selection Of

The importance of examining stained 1 to 2μ plastic sections by light microscopy has long been recognized, both for increased definition of many histologic features and for selection of specimen samples to be used in ultrastructural studies. Selection of specimens with specific orien ation relative to anatomical structures becomes of critical importance in ultrastructural investigations of organs such as the lung. The uantity of blocks necessary to locate special areas of interest by random sampling is large, however, and the method is lacking in precision. Several methods have been described for selection of specific areas for electron microscopy using light microscopic evaluation of paraffin, epoxy-infiltrated, or epoxy-embedded large blocks from which thick sections were cut. Selected areas from these thick sections were subsequently removed and re-embedded or attached to blank precasted blocks and resectioned for transmission electron microscopy (TEM).

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