scholarly journals Evaluating Soil Carbon as a Proxy for Erosion Risk in the Spatio-Temporal Complex Hydropower Catchment in Upper Pangani, Northern Tanzania

Earth ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 764-780
Author(s):  
Aloyce I. M. Amasi ◽  
Maarten Wynants ◽  
Remigius A. Kawala ◽  
Shovi F. Sawe ◽  
William H. Blake ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Aggregate Stability ◽  
Soil Erodibility ◽  
Good Representation ◽  
Strong Positive Correlation ◽  
Infiltration Capacity ◽  
Erosion Risk ◽  
Northern Tanzania

Land use conversion is generally accompanied by large changes in soil organic carbon (SOC). SOC influences soil erodibility through its broad control on aggregate stability, soil structure and infiltration capacity. However, soil erodibility is also influenced by soil properties, clay mineralogy and other human activities. This study aimed to evaluate soil organic carbon as proxy of soil erosion risk in the Nyumba ya Mungu (NYM) catchment in Northern Tanzania. Soil organic carbon (SOC) was measured by an AgroCares scanner from which the soil organic matter (SOM) was derived using the conversional van Bemmelen factor of 1.72. A regression analysis performed between the measured loss on ignition (LOI) values and SOM from the AgroScanner showed a strong positive correlation in all land use classes (LOIFL R2 = 0.85, r = 0.93, p < 0.0001; LOICL R2 = 0.86, r = 0.93, p = 0.0001; LOIGL R2 = 0.68, r = 0.83, p = 0.003; LOIBS R2 = 0.88, r = 0.94, p = 0.0001; LOIBL R2 = 0.83, r = 0.91, p = 0.0002). This indicates that SOC from the soil scanner provided a good representation of the actual SOM present in soils. The study also revealed significant differences in the soil aggregate stability (WSA) and SOM stock between the different land use types in the Upper Pangani Basin. The WSA decreases approximately in the following order: grassland > forest land > bare land > cultivated > bush land. Land use change can thus potentially increase the susceptibility of soil to erosion risk when SOC is reduced. Since WSA was directly related to SOM, the study indicates that, where formal measurements are limited, this simple and inexpensive aggregate stability test can be used by farmers to monitor changes in their soils after management changes and to tentatively assess SOC and soil health.

scholarly journals Effects of Soil Aggregate Stability on Soil Organic Carbon and Nitrogen under Land Use Change in an Erodible Region in Southwest China

2019 ◽  
Vol 16 (20) ◽  
pp. 3809 ◽  
Author(s):  
Man Liu ◽  
Guilin Han ◽  
Qian Zhang
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Organic Carbon ◽  
Southwest China ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Soil Erodibility ◽  
Agricultural Abandonment ◽  
Soil Aggregate Stability

Soil aggregate stability can indicate soil quality, and affects soil organic carbon (SOC) and soil organic nitrogen (SON) sequestration. However, for erodible soils, the effects of soil aggregate stability on SOC and SON under land use change are not well known. In this study, soil aggregate distribution, SOC and SON content, soil aggregate stability, and soil erodibility were determined in the soils at different depths along the stages following agricultural abandonment, including cropland, abandoned cropland, and native vegetation land in an erodible region of Southwest China. Soil aggregation, soil aggregate stability, and SOC and SON content in the 0–20 cm depth soils increased after agricultural abandonment, but soil texture and soil erodibility were not affected by land use change. Soil erodibility remained in a low level when SOC contents were over 20 g·kg−1, and it significantly increased with the loss of soil organic matter (SOM). The SOC and SON contents increased with soil aggregate stability. This study suggests that rapidly recovered soil aggregate stability after agricultural abandonment promotes SOM sequestration, whereas sufficient SOM can effectively maintain soil quality in karst ecological restoration.

scholarly journals Effects of Land Use Change on the Soil Organic Carbon and Selected Soil Properties in the Sultan Marshes, Turkey

2021 ◽  
Author(s):  
Selma Yaşar Korkanç ◽  
Mustafa Korkanç ◽  
Muhammet Hüseyin Mert ◽  
Abdurrahman Geçili ◽  
Yusuf Serengil
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Properties ◽  
Bulk Density ◽  
Carbon Stock ◽  
Soil Depth ◽  
Aggregate Stability ◽  
Carbon Stocks ◽  
Effects Of Land Use

Abstract This study aims the effects of land use changes on the carbon storage capacity and some soil properties of The Sultan Marshes was partially drained during the middle of the last century and converted to other land uses. Undisturbed soil sampling was performed in different land use types (rangelands, shrubs, marsh, agriculture, and dried lake area) in the wetland area at depths of 0-50 cm, and soil organic carbon (SOC), bulk density, and carbon stocks of soils for each land use type were calculated at 10 cm soil depth levels. Furthermore, disturbed soil samples were taken at two soil depths (0-20 cm and 20-40 cm), and the particle size distribution, pH, electrical conductivity (EC), aggregate stability and dispersion ratio (DR) properties of the soils were analyzed. Data were processed using ANOVA, Duncan’s test, and Pearson’s correlation analysis. The soil properties affected by land use change were SOC, carbon stock, pH, EC, aggregate stability, clay, silt, sand contents, and bulk density. SOC and carbon stocks were high in rangeland, marsh, and shrub land, while they were low in agriculture and drained lake areas. As the soil depth increased, SOC and carbon stock decreased. The organic carbon content of the soils exhibited positive relationships with aggregate stability, clay, and carbon stock, while it showed a negative correlation with bulk density, pH, and DR. The results showed that the drainage and conversion of the wetland caused a significant decrease in the carbon contents of the soils.

scholarly journals Aggregate and soil organic carbon dynamics in South Chilean Andisols

2005 ◽  
Vol 2 (2) ◽  
pp. 159-174 ◽  
Author(s):  
D. Huygens ◽  
P. Boeckx ◽  
O. Van Cleemput ◽  
C. Oyarzún ◽  
R. Godoy
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Layer ◽  
Aggregate Stability ◽  
Total Carbon ◽  
Mineralization Rate ◽  
C Mineralization ◽  
Electrostatic Charges

Abstract. Extreme sensitivity of soil organic carbon (SOC) to climate and land use change warrants further research in different terrestrial ecosystems. The aim of this study was to investigate the link between aggregate and SOC dynamics in a chronosequence of three different land uses of a south Chilean Andisol: a second growth Nothofagus obliqua forest (SGFOR), a grassland (GRASS) and a Pinus radiata plantation (PINUS). Total carbon content of the 0-10cm soil layer was higher for GRASS (6.7 kg C m-2) than for PINUS (4.3 kg C m-2, while TC content of SGFOR (5.8 kg C m-2) was not significantly different from either one. High extractable oxalate and pyrophosphate Al concentrations (varying from 20.3-24.4 g kg-1, and 3.9-11.1 g kg-1, respectively) were found in all sites. In this study, SOC and aggregate dynamics were studied using size and density fractionation experiments of the SOC, δ13C and total carbon analysis of the different SOC fractions, and C mineralization experiments. The results showed that electrostatic sorption between and among amorphous Al components and clay minerals is mainly responsible for the formation of metal-humus-clay complexes and the stabilization of soil aggregates. The process of ligand exchange between SOC and Al would be of minor importance resulting in the absence of aggregate hierarchy in this soil type. Whole soil C mineralization rate constants were highest for SGFOR and PINUS, followed by GRASS (respectively 0.495, 0.266 and 0.196 g CO2-Cm-2d-1 for the top soil layer). In contrast, incubation experiments of isolated macro organic matter fractions gave opposite results, showing that the recalcitrance of the SOC decreased in another order: PINUS>SGFOR>GRASS. We deduced that electrostatic sorption processes and physical protection of SOC in soil aggregates were the main processes determining SOC stabilization. As a result, high aggregate carbon concentrations, varying from 148 till 48 g kg-1, were encountered for all land use sites. Al availability and electrostatic charges are dependent on pH, resulting in an important influence of soil pH on aggregate stability. Recalcitrance of the SOC did not appear to largely affect SOC stabilization. Statistical correlations between extractable amorphous Al contents, aggregate stability and C mineralization rate constants were encountered, supporting this hypothesis. Land use changes affected SOC dynamics and aggregate stability by modifying soil pH (and thus electrostatic charges and available Al content), root SOC input and management practices (such as ploughing and accompanying drying of the soil).

scholarly journals Aggregate structure and stability linked to carbon dynamics in a south Chilean Andisol

2005 ◽  
Vol 2 (1) ◽  
pp. 203-238 ◽  
Author(s):  
D. Huygens ◽  
P. Boeckx ◽  
O. Van Cleemput ◽  
R Godoy ◽  
C. Oyarzún
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Carbon Dynamics ◽  
C Mineralization ◽  
Physical Protection ◽  
Soil C

Abstract. The extreme vulnerability of soil organic carbon to climate and land use change emphasizes the need for further research in different terrestrial ecosystems. We have studied the aggregate stability and carbon dynamics in a chronosequence of three different land uses in a south Chilean Andisols: a second growth Nothofagus obliqua forest (SGFOR), a grassland (GRASS) and a Pinus radiata plantation (PINUS). The aim of this study was to investigate the role of Al as soil organic matter stabilizing agent in this Andisol. In a case study, we linked differences in carbon dynamics between the three land use treatments to physical protection and recalcitrance of the soil organic matter (SOM). In this study, C aggregate stability and dynamics were studied using size and density fractionation experiments of the SOM, δ13C and total carbon analysis of the different SOM fractions, and mineralization measurements. The results showed that electrostatic attractions between and among Al-oxides and clay minerals are mainly responsible for the stabilization of soil aggregates and the physical protection of the enclosed soil organic carbon. Whole soil C mineralization rate constants were highest for SGFOR and PINUS, followed by GRASS. In contrast, incubation experiments of isolated macro organic matter fractions showed that the recalcitrance of the SOM decreased in another order: PINUS > SGFOR > GRASS. We concluded that physical protection of soil aggregates was the main process determining whole soil C mineralization. Land use changes affected soil organic carbon dynamics in this south Chilean Andisol by altering soil pH and consequently available Al.

Soil Structural Stability and Extracellular Polymeric Substances (EPS): transient binding agents affected by land-use.

2020 ◽  
Author(s):  
Marc Redmile-Gordon
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Structural Stability ◽  
Extracellular Polymeric Substances ◽  
Aggregate Stability ◽  
Land Uses ◽  
Total Soil ◽  
Binding Agents ◽  
Soil Structural Stability

&lt;p&gt;Structural stability in agricultural soils is said to be maintained through production of &amp;#8216;biological binding agents&amp;#8217;, including temporary binding agents (fungi, roots), transient binding agents (EPS), and persistent binding agents (of less certain origin). We sampled soils from a long-term field trial, comprising previous grassland, arable and fallow land-uses in factorial combination with current land-uses of the same type: previous 3 land-uses &amp;#160;x current 3 land-uses = 9 treatments (Redmile-Gordon et al., 2020). Total soil organic carbon (SOC), EPS (including protein, and polysaccharide fractions; Redmile-Gordon et al., 2014), and mean weight diameter (MWD) of water stable aggregates (Le Bissonnais, 1996) were quantified.&lt;/p&gt;&lt;p&gt;Both EPS and MWD were correlated, and were both strongly influenced by current land-use (implemented 2.5 years before sampling), but not by previous land-use (implemented &gt; 50 years ago, terminated 2.5 years before sampling). While exopolysaccharides were significantly correlated to the soil&amp;#8217;s structural stability (p = 0.027), proteinaceous EPS were more closely related to the associated gains in soil aggregate stability (p = 0.002).&lt;/p&gt;&lt;p&gt;In contrast to EPS and soil stability, total soil organic carbon (SOC) was strongly influenced by previous land-use. Importantly, this indicates that any capacity for relatively stable organic matter to contribute to the soil&amp;#8217;s structural stability is overwhelmed by temporary/transient effects owed to current land-use. This is cause for optimism, as it seems the physical quality of soils might be improved by short-term application of managements that favour EPS production. This approach would represent a qualitative step beyond that of building total SOC, which can be difficult for land-managers to achieve. This study is the first to simultaneously assess the effects of land-use on proteinaceous and polysaccharide content of EPS, and link this to the structural stability of soils. Further understanding surrounding the ecology of EPS production, and disentangling the contributions of temporary (largely physical) vs. transient (biochemical) binding agents is hoped to contribute to the development of more efficient land-management strategies.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Le Bissonnais, Y., &lt;strong&gt;1996&lt;/strong&gt;. Aggregate stability and assessment of soil crustability and erodibility.&lt;br&gt;1. Theory and methodology. Eur. J. Soil Sci. 47, 425&amp;#8211;437.&lt;/p&gt;&lt;p&gt;Redmile-Gordon, M., Brookes, P.C., Evershed, R.P., Goulding, K.W.T., Hirsch, P.R., &lt;strong&gt;2014&lt;/strong&gt;. Measuring the soil-microbial interface: extraction of extracellular polymeric substances (EPS) from soil biofilms. Soil Biol. Biochem. 72, 163&amp;#8211;171.&lt;/p&gt;&lt;p&gt;Redmile-Gordon, M., Gregory, A.S., White, R.P., Watts, C.W. &lt;strong&gt;2020&lt;/strong&gt;. Soil organic carbon, extracellular polymeric substances (EPS), and soil structural stability as affected by previous and current land-use. Geoderma, 363. https://doi.org/10.1016/j.geoderma.2019.114143&lt;/p&gt;

scholarly journals Influence of Slope Gradient and Aspect on Soil Organic Carbon Content in the Region of Niš, Serbia

2021 ◽  
Vol 13 (15) ◽  
pp. 8332
Author(s):  
Snežana Jakšić ◽  
Jordana Ninkov ◽  
Stanko Milić ◽  
Jovica Vasin ◽  
Milorad Živanov ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Distribution ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Slope Aspect ◽  
Available Phosphorus ◽  
Organic Carbon Content ◽  
Slope Gradient ◽  
Phosphorus And Potassium ◽  
Uncultivated Land

Topography-induced microclimate differences determine the local spatial variation of soil characteristics as topographic factors may play the most essential role in changing the climatic pattern. The aim of this study was to investigate the spatial distribution of soil organic carbon (SOC) with respect to the slope gradient and aspect, and to quantify their influence on SOC within different land use/cover classes. The study area is the Region of Niš in Serbia, which is characterized by complex topography with large variability in the spatial distribution of SOC. Soil samples at 0–30 cm and 30–60 cm were collected from different slope gradients and aspects in each of the three land use/cover classes. The results showed that the slope aspect significantly influenced the spatial distribution of SOC in the forest and vineyard soils, where N- and NW-facing soils had the highest level of organic carbon in the topsoil. There were no similar patterns in the uncultivated land. No significant differences were found in the subsoil. Organic carbon content was higher in the topsoil, regardless of the slope of the terrain. The mean SOC content in forest land decreased with increasing slope, but the difference was not statistically significant. In vineyards and uncultivated land, the SOC content was not predominantly determined by the slope gradient. No significant variations across slope gradients were found for all observed soil properties, except for available phosphorus and potassium. A positive correlation was observed between SOC and total nitrogen, clay, silt, and available phosphorus and potassium, while a negative correlation with coarse sand was detected. The slope aspect in relation to different land use/cover classes could provide an important reference for land management strategies in light of sustainable development.

scholarly journals Dynamics of Soil Organic Carbon and Labile Carbon Fractions in Soil Aggregates Affected by Different Tillage Managements

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
No Tillage ◽  
Labile Carbon ◽  
Carbon Fractions ◽  
Soil Aggregate Stability ◽  
Positive Effects

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.

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