CORRELATING EROSION PROPERTIES TO ORGANIC CARBON CONTENT

Top PDF CORRELATING EROSION PROPERTIES TO ORGANIC CARBON CONTENT:

Soil erosion and organic carbon export by wet snow avalanches

Soil erosion and organic carbon export by wet snow avalanches

Fig. 4. Probability-density estimates of simulated and field-derived log 10 -transformed specific sediment and organic yields from wet snow avalanches in the area around Davos, eastern Swiss Alps. Simulations assumed power-law distributed avalanche-deposit ar- eas with varying arbitrary minimum debris-covered areas A min , and randomly sampled deposit thicknesses based on field measurements (each thick line represents one avalanche cone; dashed lines are pooled for all sites; see text for details). Thick red lines are esti- mates derived from linear interpolation of debris content measured from 1 m 2 sample squares. More than 90 % of the estimated sed- iment and carbon yields are spread over three and four orders of magnitude, respectively.
Show more

8 Read more

Prediction of soil organic carbon loss due to erosion in Girindulu Watersheds

Prediction of soil organic carbon loss due to erosion in Girindulu Watersheds

The decrease of soil organic carbon content made the decrease of the capacity of the soil to hold water. This made agricultural lands in the Girindulu watershed were shortage of water in the dry season. In addition, soil cracks occurred in some areas resulting in crop failure. To reduce the rate of soil erosion and soil organic carbon loss in the Girindulu watershed, soil conservation measures that need to be conducted are replanting trees (reforestation) on less productive land, incorporating agricultural residues, mulching, bench terracing, and using organic fertilizer on farmland of 2.0-2.5 t/ha/year. The use of organic fertilizers such as manure on agricultural land is recommended, as the source was locally available.
Show more

8 Read more

Enrichment of organic carbon in sediment transport by interrill and rill erosion processes

Enrichment of organic carbon in sediment transport by interrill and rill erosion processes

would have been important, the ER OC should decrease with increasing Ek because of a more complete breakdown of the aggregates. This trend could not be observed in our results (Fig. 1), however, and Ek was found to be an insignifi cant variable in the stepwise regression analysis. Analysis of the OC content in the different aggregate fractions obtained after wet sieving did not show a signifi cant increase in OC (at the 0.05 level) with decreasing aggregate size (Table 2). This indicates a rather homogeneous distribution of OC within the aggregates. This was also observed by Schiettecatte (2006) for the OC content and textural composition of different aggregate classes, which had been separated by dry sieving the same soil used in our study. Therefore, we can conclude that for the soil under study, detachment by raindrop impact is an unselective process. This agrees with the results of Gabriels and Moldenhauer (1978), who found that for different soil types (fi ne sand, silt loam, silty clay loam, and silty clay), the particle size distribution of detached material by splash erosion was not signifi cantly dif- ferent from that of the original soil.
Show more

6 Read more

Erosion-induced massive organic carbon burial and carbon emission in the Yellow River basin, China

Erosion-induced massive organic carbon burial and carbon emission in the Yellow River basin, China

With respect to the OC, approximately 49.5 % (0.53 ± 0.21 Gt) was buried in the river system and 23.5 % (0.25 ± 0.14 Gt) was delivered into the ocean (Fig. 6b). The decomposed OC represents about 27 % of the total eroded OC on average. Considering the fairly stable OC content along the mainstem channel, it indicates that the labile fraction has been largely oxidized before reaching the ocean. Thus, it can be concluded that approximately the labile fraction accounts for one-quarter of the total eroded OC, validating the commonly held assumption that about 20–40 % of the displaced OC is mineralized (Davidson and Ackerman, 1993; Lal, 2003; Quinton et al., 2010; Berhe et al., 2007). Nevertheless, the obtained decomposition shows great uncertainty (Fig. 6b), suggesting the complexity in estimating the magnitude of OC decomposition. In contrast to the Yellow River characterized by low SOC (0.84 %), more OC is vulnerable to decomposition for river basins with high SOC content. In addition, the human-induced OC redistribution represents a total of 34.2 % of the eroded OC (Fig. 6b), which is slightly larger than the decomposed frac- tion. Particularly, about half of the terrestrially redeposited OC (49.4 %) was buried behind dams, highlighting the importance of dams in sequestering the eroded OC. Without human activities, particularly silt check dams and slope soil control measures that are able to stabilize large amounts of sediment quickly after erosion, more OC would have been oxidized as transported en route to the ocean. Furthermore, the seaward OC flux would have been larger if no sediment was redisplaced in the river system by humans.
Show more

15 Read more

Selective organic carbon losses from soils by sheet erosion and main controls

Selective organic carbon losses from soils by sheet erosion and main controls

Burkina Faso utilizing 22·2-m long plots, depletion rates as high as 16% were observed (Roose, 1978). Moreover, in a Kenyan study conducted by Boye and Albrecht (2006, it was observed that sediments eroded from 1-m plots were enriched by a factor of 3·3 in organic carbon (OC). The OC enrichment ratio (ER) was 4·3 for a biennial cotton/corn rotation fields in a study performed in Burkina Faso (Bilgo et al., 2006), ranging between 4·3 and 4·8 for sandy soils in South Africa, measured with 10 m long plots (Mchunu et al., 2011) and as high as 10 in the sandy, semi-arid environment of Mali (Drissa et al., 2004). In their review of tropical and Mediterranean soils, Roose and Barthès (2006 pointed to ER values in the range between 0·5 and 14, with values below 1·1 occurring for tilled soils, while values over 3·0 were calculated for natural vegetation (e.g. forest, savanna, or fallow). While the preferen- tial export of SOC from soils by water erosion has been observed and acknowledged, little is known about the main mechanisms and controlling actions. Schiettecatte et al. ’s (2008 laboratory simulated rainfall study, investigating rain- impacted-flow (RIF), revealed that high intensity storms are less preferentially selective regarding the transportation of OC, than low intensity events. Can these results, however, be applied to field conditions, in particular when the natural environment and large areas are considered (Wang et al., 2010)? Do the soil properties, land use and management, topography and terrain morphology not also affect the selectivity of OC erosion by water? Moreover, what would the impact be considering a combination of these respective fac- tors? These important questions remain largely unanswered.
Show more

10 Read more

Water content, organic carbon and dry bulk density in flooded sediments

Water content, organic carbon and dry bulk density in flooded sediments

Faculty of Agricultural Engineering, Technion — Israel Institute of Technology, Haifa 32000 , Israel Received 3 November 2000; accepted 19 March 2001 Abstract Several basic properties of pond bottom soil are shown to be related, a relation that enable to evaluate pond bottom soil characteristics through the determination of one parameter (e.g. soil moisture). In addition, these relationships give some insight into the properties of flooded sediments. Unlike terrestrial soils, made of gas, liquid and solid phases, flooded sediments are made practically of only two phases, liquid and solid. Since all voids are filled with water, it is possible to evaluate soil porosity and bulk density, directly from the moisture content of the soil, a property easily determined. The correlation between bulk density and organic matter was tested in six different systems (n = 868), including rivers and fish pond sediments in Israel, fish pond sediments in Alabama, USA, and Abbassa, Egypt, lake sediments in New Zealand, alpine lake sediments in Colorado, USA, and sea floor sediments from the Northwest African continental slope. Sediment bulk density was inversely related to the organic carbon concentration. The regression for all the data points was:
Show more

9 Read more

Organic carbon content and mineralization characteristics of soil in a subtropical Pinus massoniana forest

Organic carbon content and mineralization characteristics of soil in a subtropical Pinus massoniana forest

4.1 For all three forest types, the organic carbon content and active carbon content of soil layers gradually decreased with the increase in soil depth and were relatively enriched in the surface layers. Previous research indicated that 47.53-71.73% of the fine roots of P. massoniana were concentrated within the 0-20 cm soil layer, with a decreasing trend in biomass with increasing soil depth. Large quantities of dead fine roots jointly decompose with surface litter, providing a rich carbon source for the topsoil and thereby directly affecting the vertical distribution of soil organic carbon[20,21]. These effects are also manifested in the vertical distribution of active carbon in soil layers because the aforementioned root and litter properties cause the active carbon content to be higher in the 0-20 cm soil layer compared with subsoil layers and produce the same vertical variation in the active carbon content as that observed for the soil organic carbon content (Table 4).
Show more

7 Read more

Reference Area Method for Mapping Soil Organic Carbon Content at Regional Scale

Reference Area Method for Mapping Soil Organic Carbon Content at Regional Scale

various spatial and temporal scales. Studies use various approaches to predict soil properties or classes including univariate and multi-variate statistical, geostatistical and hybrid methods, and process-based models that relate soils to environmental covariates considering spatial and temporal dimensions (Grunwald, 2010). Decision-making in the field of agriculture and environment ideally requires a precise knowledge of soils over wide regions. However, detailed soil surveys are only possible over limited area because high costs of systematic soil mapping and soil property measurements (Lagacherie et al, 2001). When dealing with areas of different sizes and with information available at different scales, policy makers and decision makers need to either upscale their evaluations and simulations from small to large scale or downscale from large to small scale (Stein et al., 2001).
Show more

9 Read more

Effect of organic fertilizers on soil organic carbon and risk trace elements content in soil under permanent grassland

Effect of organic fertilizers on soil organic carbon and risk trace elements content in soil under permanent grassland

1999). Stability or lability of any organic carbon frac- tion could be due to either chemical composition or protection within the soil aggregates. Stable organic carbon forms are characterized by redox properties and can act as electron acceptors or donors in natural environment. They can influence the oxidation state of metal ions and thus their speciation and mobility (Palmer et al. 2006; Aeschbacher et al. 2010). Chemi- cal forms, metal ion complexation by humic substances

8 Read more

Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks

Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks

Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks Reisser, Moritz ; Purves, Ross S ; Schmidt, Michael W I ; Abiven, Samuel Abstract: Pyrogenic carbon (PyC) is considere done of the most stable components in soil and can represent more than 30% of total soil organic carbon (SOC). However, few estimates of global PyC stock or distribution exist and thus PyC is not included in any global carbon cycle models, despite its potential major relevance for the soil pool. To obtain a global picture, were viewed the literature for published PyC content in SOC data. We generated the first PyC database including more than 560 measurements from 55 studies. Despite limitations due to heterogeneous distribution of the studied locations and gaps in the database, we were able to produce a world wide PyC inventory. We found that global PyC represent on average 13.7% of the SOC and can be even up to 60%, making it one of the largest groups of identifiable compounds in soil, together with polysaccharides. We observed a consistent range of PyC contentin SOC, despite the diverse methods of quantification. We tested the PyC content against different environmental explanatory variables: fire and landuse (fire characteristics,land use,net primary productivity), climate (temperature, precipitation, climatic zones, altitude),and pedogenic properties (clay content, pH, SOC content). Surprisingly, soil properties explain PyCc ontent the most. Soils with clay content higher than 50% contain significantly more PyC (>30% of the SOC) than with clay content lower than 5%(<6% of the SOC). Alkaline soils contain at least 50% more PyC thanacidic soils. Furthermore, climatic conditions, represented by climatic zone or mean temperature or precipitation, correlate significantly with the PyC content. Byc ontrast, fire characteristics could only explain PyC content, if site-specific information was available. Datasets derived from remote sensing did not explain the PyC content. To show the potential of this database, we used it in combination with other global datasets to create a global world wide PyC content and a stock estimation, which resulted in a round 200 PgPyC for the upper most 2m. These modeled estimates indicated a clear mismatch between the location of the current PyC studies and the geographical zones where we expect high PyC stocks.
Show more

16 Read more

Effects of Soil Compaction and Organic Carbon Content on Preferential Flow in Loamy Field Soils

Effects of Soil Compaction and Organic Carbon Content on Preferential Flow in Loamy Field Soils

Figure 2 depicts the CL as well as the fines fraction plotted against OC for the Faardrup and Silstrup soils. The solid line rep- resents a CL-to-OC ratio of n = 10. In general, the content of fines tional properties at Silstrup (Norgaard et al., 2012), Fig. 3 shows measured BTC for Faardrup grouped for different BD ranges in ascending order. Breakthrough curves with less than 40% tritium mass recovery are depicted in black. Norgaard et al. (2012) showed that BD is an important soil parameter that reflects devel- opment and evolution of structural pores and associated preferen- tial flow and transport processes. The shapes of the BTC in Fig. 3 varied from relatively symmetrical with slight left skews to very pronounced left skews with large and early tritium arrival peaks.
Show more

11 Read more

Evaluation of Soil Organic Carbon and Soil Moisture Content from Agricultural Fields in Mississippi

Evaluation of Soil Organic Carbon and Soil Moisture Content from Agricultural Fields in Mississippi

2.2. Site Selection Study fields were chosen based on characteristics which are typical of each study watershed. Details of the loca- tions and characteristics for each sampling point are summarized in Table 1 and are pictured in Figures 3 and 4. TCW has six sampling points all in crop land use while the UPRW has six points split between forestland and pastureland. All study areas were located on pri- vately owned property and sampling was conducted with the permission of the landowners. In the TCW two crop fields with historical corn-soybean plant rotations were chosen. Field 1 is 22 ha (54 ac) and has been harvested the last 30 years with a corn-soybean rotation. Field 2 is approximately 121 ha (300 ac) that has been planted with corn, soybeans and cotton for the last 20 years. Both properties are directly adjacent to Town Creek within the watershed.
Show more

10 Read more

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

In our current research attempting to define critical small SOM contents for soil structural properties based on the clay con- tent ( < 2 μm)/SOC and particles < 20 μm (Fines20)/SOC ratios (Schjønning et al., 2012; Getahun et al., 2016; Jensenet al., 2017a), it is essential to have access to reliable values of SOC con- tent. The combined fraction of clay plus silt (particles < 20 μm) is denoted Fines20. As a ‘spin-off’ from this research, we revis- ited the conversion of LOI to SOC. Data for temperate zone arable topsoil with different contents of SOC were collected from long-term agricultural field experiments with contrasting manage- ment at Askov (Denmark) and Rothamsted (UK), and from a texture gradient in a farmer’s field at Lerbjerg (Denmark) with uniform management and mineralogy. These fields had large ranges in LOI, SOC, clay and Fines20, making them represen- tative of arable soils with respect to these properties. We also included clay-, silt- and sand-sized fractions isolated from Lerbjerg soil samples.
Show more

9 Read more

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

revisited the conversion of LOI to SOC. Data for temperate zone arable topsoils with different contents of SOC were collected from long-term agricultural field experiments with contrasting management at Askov (Denmark) and Rothamsted (UK), and from a texture gradient in an arable farmer’s field at Lerbjerg (Denmark) with uniform management and mineralogy. These fields had large ranges in LOI, SOC, clay and Fines20 making them rather representative for arable soils with respect to these properties. We also included clay-, silt- and sand-sized fractions isolated from Lerbjerg soils.
Show more

31 Read more

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

Converting loss-on-ignition to organic carbon content in arable topsoil: Pitfalls and proposed procedure

In our current research attempting to define critical small SOM contents for soil structural properties based on the clay con- tent ( < 2 μm)/SOC and particles < 20 μm (Fines20)/SOC ratios (Schjønning et al., 2012; Getahun et al., 2016; Jensenet al., 2017a), it is essential to have access to reliable values of SOC con- tent. The combined fraction of clay plus silt (particles < 20 μm) is denoted Fines20. As a ‘spin-off’ from this research, we revis- ited the conversion of LOI to SOC. Data for temperate zone arable topsoil with different contents of SOC were collected from long-term agricultural field experiments with contrasting manage- ment at Askov (Denmark) and Rothamsted (UK), and from a texture gradient in a farmer’s field at Lerbjerg (Denmark) with uniform management and mineralogy. These fields had large ranges in LOI, SOC, clay and Fines20, making them represen- tative of arable soils with respect to these properties. We also included clay-, silt- and sand-sized fractions isolated from Lerbjerg soil samples.
Show more

9 Read more

Determination of Extraction Efficiency of Different Solvents for Organic Carbon Content in Biomass Combustion Aerosols

Determination of Extraction Efficiency of Different Solvents for Organic Carbon Content in Biomass Combustion Aerosols

it has been treated as a compound that primarily scatters light and has invariant properties [14]. In fact, chemical and optical properties of OC may differ due to the nature of the OC source [15]. The present paper aims to contribute to understanding the variable behaviour of BrC regarding its polarity. BrC constituents exhibit characteristic of polar molecules and contain both water soluble & insoluble components. For that purpose, in current study four different solvents used for qualitative study of brown carbon composition.
Show more

5 Read more

Foresttopsoil organic carbon content inSouthwest Bohemiaregion

Foresttopsoil organic carbon content inSouthwest Bohemiaregion

Of the tested classifiers, both tree species and several of the stand site type categories revealed significant differences in SOC in both organic and mineral layer. This is vital for the purpose of regional extrapolation, which should be based on the classifier that suitably reflects the overall site conditions, including climate, soil type and type of forest vegetation. In this respect, the categoriza- tion based on forest site types as used in the Czech forest typology seems to be promising. Forest type categories integrate the key site parameters and provide good approximate characteristics that affect SOC. Although this study provides a good foundation for categorization of SOC by stand site types, it is obvious that further analysis is needed and it should involve also other regions of the country. Since the map of forest site types is already available in digital form for the whole country (Macků – unpublished results), it could be used to target the most important forest site types and optimally stratify additional soil sampling needed.
Show more

12 Read more

Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance.

Erosion of organic carbon from the Andes and its affects on ecosystem carbon dioxide balance.

Acknowledgments This paper is a product of the Andes Biodiversity and Ecosystems Research Group (ABERG). K.E.C. was funded by the Natural Sciences and Engineering Research Council of Canada (362718- 2008 PGS-D3) and Clarendon Fund PhD scholarships. R.G.H. was supported by a NERC New Investigator Grant (NE/ I001719/1) and a European Research Council Starting Grant ROC-CO 2 (678779). A.J.W. was supported to work in the Kosñipata catchment by NSF-EAR 1227192 and 1455352. Y.M. is sup- ported by the Jackson Foundation and a European Research Council advanced investigator grant GEM-TRAITS (321131) under the European Union’s Seventh Framework Programme (FP7/2007 – 2013). We thank ACCA Peru (Wayqecha) and Inkaterra (San Pedro) for the field support and L.V. Morales, R.J. Abarca Martínez, M.H. Yucra Hurtado, R. Paja Yurca, J.A. Gibaja Lopez, I. Cuba Torres, J. Huamán Ovalle, A. Alfaro-Tapia, R. Butrón Loayza, J. Farfan Flores, D. Oviedo Licona, and D. Ocampo for the field assistance. The Carnegie Airborne Observatory is made possible by the Avatar Alliance Foundation, Grantham Foundation for the Protection of the Environment, John D. and Catherine T. MacArthur Foundation, Gordon and Betty Moore Foundation, W.M. Keck Foundation, Margaret A. Cargill Foundation, Mary Anne Nyburg Baker and G. Leonard Baker Jr., and William R. Hearst III. We thank D. Knapp, T. Kennedy-Bowdoin, C. Anderson, and R. Tupayachi for the CAO data collection and analysis. We thank S. Waldron, S. Dadson, S. Lane, S. Feakins, and C. Ponton for their helpful discussions and comments prior to submission and V. Galy for suggesting the radio- carbon analysis of the poststorm sam- ples. We thank Editor M. Goni and two anonymous reviewers for their com- ments on the paper which helped improve the manuscript. Data not included in the tables in
Show more

22 Read more

Organic molecular structures Special properties of carbon

Organic molecular structures Special properties of carbon

In the alkynes there must be at least one triple bond between two of the carbon atoms. They are unsaturated compounds and are therefore more reactive than alkanes. Their general formula is C n H 2n-2 . For example but-1-yne has the molecular formula C 4 H 6 . The simplest alkyne is ethyne (Figure 4.25), also known as acetylene. Many of the alkynes are used to synthesise other chemical products.

24 Read more

Total and labile organic carbon content in agroecological system

Total and labile organic carbon content in agroecological system

PALAVRAS-CHAVE: Matéria orgânica; biomassa microbiana; decomposição; solo fumigado; composto orgânico. ABSTRACT: In an intercropping lettuce-carrot system submitted to crescent dosages of organic compost (0; 12; 24; 48 Mg ha -1 ) were monitored carbon from soil microbial biomass (MBC), labile carbon in fumigated soil (LCF), in non-fumigated soil (LCNF), in autoclaved soil (LCA) and total organic carbon (TOC) at 0-10 cm of depth. Pasture and forest areas surrounding the experiment were used as reference. Five samples from soil were evaluated at 8 days before the beginning of the experiment, 0; 6; 60 and 114 days after manuring (dam). LCF was the attribute that presented the most consistent correlation with TOC that is usually utilized to detect changes in soil organic matter. Increasing dosages of organic compost caused the increase of MBC, LCF, LCNF, LCA and TOC. From 60 days after planting and forward, MBC and LCF presented decrease of their levels according to the quality of organic compost. Pasture and forest soils behave as contrasts, holding lower and higher content of carbon of soil, respectively.
Show more

9 Read more

Show all 10000 documents...