Determining soil organic carbon for agricultural soils: a comparison between the Walkley & Black and the dry combustion methods (north Belgium)

The soil organic carbon content was analyzed in more than 7 000 soil samples under different land uses, climates and lithologies from northern Spain (Galicia, Asturias, Cantábria y País Vasco). GIS maps (1:50 000) were made of the % SOC and SOC stocks. The % SOC varies according to land use (higher in forest and scrub soils and lower in agricultural soils) and climate, and there is a highly significant correlation between SOC content and mean annual precipitation. There are significant differences between the soils of Galicia/Western Asturias (GAw) and those of the rest of the study area (Central and Eastern Asturias, Cantabria and País Vasco) (AceCV), although these are neighbouring regions. In forest and/or scrub soils with a udic soil moisture regime, in GAw, the SOC is usually > 7% and the average stocks 260 t ha -1 (0-30 cm), and >340 t ha-1 (0-50 cm) in soils with thick organic matter rich horizons (> 40 cm); these values greatly exceed the average contents observed in forest soils from temperate zones. Under similar conditions of vegetation and climate in soils of AceCV the SOC average is 3% and the mean stocks 90-100 t ha-1 (0-30 cm). The andic character of acid forest soils in GAw and the formation of C-Al,Fe complexes are pointed out as the SOC stabilization mechanism, in contrast to the neutral and calcareous soils that predominate in AceCV, where the main species of OC are easily biodegradable.

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Organic matter mineralisation in contrasting agricultural soils amended with sewage sludge .

Spanish Journal of Soil Science ◽

10.3232/sjss.2014.v4.n2.02 ◽

2014 ◽

Vol 4 ◽

Author(s):

Jose Navarro Pedreño ◽

Ignacio Gómez Lucas ◽

Jose Martín Soriano Disla

Keyword(s):

Organic Matter ◽

Single Dose ◽

Sewage Sludge ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Agricultural Soils ◽

Dry Weight ◽

Soil C ◽

Multiple Sensor ◽

Sludge Application

The mineralisation of organic matter (OM) when sewage sludge was used as amendment in 70 contrasting agricultural soils from Spain was analysed. Soils received a single dose of sewage sludge (equivalent to 50t dry weight ha-1) and the O2 consumption was continuously monitored for 30 days using a multiple sensor respirometer in a laboratory experiment. The cumulative O2 consumption and rates after 8 and 30 days of incubation (O2 cum 8d, 30d and O2 rate 8d, 30d), the respiratory quotient (RQ), the maximum O2 rates over the incubation period (O2 max) and time from the beginning of the incubation when O2 max occurred (Tmax), were determined in both amended and non-amended soils. Sewage sludge application resulted in increased values for O2 max, O2 rate 8d, and O2 cum 30d. Differences were minor for Tmax, RQ 8d and O2 rate 30d. A considerable amount of the initial OM applied was mineralised during the first 8 days. Organic matter decomposition (as expressed by O2 cum 30d) was favoured in soils with high values of pH, carbonates, soil organic carbon and low values of amorphous Mn. Soils with these characteristics may potentially lose soil C after sewage sludge application.

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Soil organic carbon stocks are systematically overestimated by misuse of the parameters bulk density and stone content

10.5194/soil-2016-78 ◽

2016 ◽

Author(s):

Christopher Poeplau ◽

Cora Vos ◽

Axel Don

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Bulk Density ◽

Agricultural Soils ◽

Soil Layer ◽

Future Studies ◽

Soil Organic Carbon Stocks ◽

Soc Stock ◽

The Mean ◽

Soc Stocks

Abstract. Estimation of soil organic carbon (SOC) stocks requires estimates of the carbon content, bulk density, stone content and depth of a respective soil layer. However, different application of these parameters could introduce a considerable bias. Here, we explain why three out of four frequently applied methods overestimate SOC stocks. In stone rich soils (> 30 Vol. %), SOC stocks could be overestimated by more than 100 %, as revealed by using German Agricultural Soil Inventory data. Due to relatively low stone content, the mean systematic overestimation for German agricultural soils was 2.1–10.1 % for three different commonly used equations. The equation ensemble as re-formulated here might help to unify SOC stock determination and avoid overestimation in future studies.

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Application of RothC model to predict soil organic carbon stock on agricultural soils of Slovakia

Soil and Water Research ◽

10.17221/23/2009-swr ◽

2010 ◽

Vol 5 (No. 1) ◽

pp. 1-9 ◽

Cited By ~ 10

Author(s):

G. Barančíková ◽

J. Halás ◽

M. Gutteková ◽

J. Makovníková ◽

M. Nováková ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Stock ◽

Agricultural Land ◽

Agricultural Soils ◽

Plant Residues ◽

Soil Organic Carbon Stock ◽

Rothc Model ◽

Soc Stock ◽

Organic Carbon Stock

Soil organic matter (SOM) takes part in many environmental functions and, depending on the conditions, it can be a source or a sink of the greenhouse gases. Presently, the changes in soil organic carbon (SOC) stock can arise because of the climatic changes or changes in the land use and land management. A promising method in the estimation of SOC changes is modelling, one of the most used models for the prediction of changes in soil organic carbon stock on agricultural land being the RothC model. Because of its simplicity and availability of the input data, RothC was used for testing the efficiency to predict the development of SOC stock during 35-year period on agricultural land of Slovakia. The received data show an increase of SOC stock during the first (20 years) phase and no significant changes in the course of the second part of modelling. The increase of SOC stock in the first phase can be explained by a high carbon input of plant residues and manure and a lower temperature in comparison with the second modelling part.

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