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.

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.

scholarly journals The Effect of Anaerobic Digestate on the Soil Organic Carbon and Humified Carbon Fractions in Different Land-Use Systems in Lithuania

Land ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 133
Author(s):  
Alvyra Slepetiene ◽  
Mykola Kochiieru ◽  
Linas Jurgutis ◽  
Audrone Mankeviciene ◽  
Aida Skersiene ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Field Experiments ◽  
Soil Layer ◽  
Fertilization Rate ◽  
Agricultural System ◽  
Main Task ◽  
Carbon Fractions ◽  
Fertilization Effects

The most important component of agricultural system are soils as the basis for the growth of plants, accumulation of water, plant nutrients and organic matter. The main task of our research was to ascertain changes in soil organic carbon (SOC) and mobile humified carbon fractions in digestate-treated soils. We have performed three field experiments using the same design on two soil types in 2019–2020. We studied the fertilization effects of different phases of digestate on Retisol and Fluvisol. Fertilization treatments: control; separated liquid digestate 85 kg ha−1 N; and 170 kg ha−1 170 N; separated solid digestate 85 kg ha−1 N; and 170 kg ha−1 N. We have found a greater positive effect on the increase in SOC because of the use of the maximum recommended fertilization rate of the solid digestate. The content of mobile humic substances (MHS) tended to increase in grassland and crop rotation field in digestate-treated soil. In our experiment, maximum concentration of SOC was found in 0–10 cm soil layer, while in the deeper layers the amount of SOC, MHS and mobile humic acids proportionally decreased. We concluded, that long-term factors as soil type and land use strongly affected the humification level expressed as HD (%) in the soil and the highest HD was determined in the grassland soil in Fluvisol.

scholarly journals Effects of atrazine application on soil aggregates, soil organic carbon and glomalin-related soil protein

2021 ◽  
Vol 67 (No. 3) ◽  
pp. 173-181
Author(s):  
Yufei Liu ◽  
Xiaoxu Fan ◽  
Tong Zhang ◽  
Xin Sui ◽  
Fuqiang Song
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Mass Fraction ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Allowable Limit ◽  
Limit Value ◽  
Aggregate Composition ◽  
Soil Protein

Atrazine is still widely used in China. Atrazine residue (1.86–1 100 mg/kg) in the soil has exceeded the allowable limit (1.0 mg/kg), affecting soil structure and soil aggregate composition. To understand the long-term application of atrazine on soil aggregates and the binding agent, four treatments were established in cornfield planted since 1998, including without atrazine applied (AT<sub>0</sub>), atrazine applied (28% atrazine, 1 200–1 350 mL/ha/year) once a year from 2012 to 2018 (AT<sub>6</sub>, 167 mg/kg), from 2008 to 2018 (AT<sub>10</sub>, 127.64 mg/kg) as well as from 2002 to 2018 (AT<sub>16</sub>, 102 mg/kg) with three replications. Along with the increase of atrazine application time, the mass fraction of soil aggregates &gt; 5 mm and 2–5 mm decreased significantly while the mass fraction of soil aggregates 0.5–2 mm and &lt; 0.5 mm increased gradually, and the change of aggregate binding agents contents were the same as that of aggregates. The contents of soil organic carbon (SOC) and glomalin-related soil protein (GRSP) in the aggregates &gt; 5 mm and 2–5 mm were significantly negatively correlated with the years of atrazine application. Our results show that although atrazine residue in the soil does not increase with the increased yearly application, its concentration is still markedly higher than the permitted limit value and seriously affected the content of SOC and GRSP of aggregates &gt; 2 mm, which can lead to a decrease of soil aggregate stability and soil quality.  

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 Soil organic carbon mineralization in relation to microbial dynamics in subtropical red soils dominated by differently sized aggregates

2019 ◽  
Vol 17 (1) ◽  
pp. 381-391
Author(s):  
Jinquan Huang ◽  
Changwei Zhang ◽  
Dongbing Cheng ◽  
Bo Hu ◽  
Pingcang Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Bacterial Species ◽  
Water Erosion ◽  
Mineralization Rate ◽  
Microbial Dynamics ◽  
Selective Transport ◽  
Red Soils ◽  
Soc Mineralization

AbstractThe dynamics of eroded and retained soil organic carbon (SOC) may provide critical clues for evaluating impacts of soil erosion on global carbon cycling. Distribution patterns of soil aggregates in eroded and deposited environments are shaped by selective transport of water erosion. Therefore, detecting the pattern of SOC mineralization in soils dominated by aggregates of different sizes is essential to accurately explore the dynamics of eroded and retained SOCs in eroded and deposited environments. In the present study, the characteristics of SOC mineralization and its relationship to microbial dynamics in subtropical red soils dominated by different sizes of soil aggregates were investigated. The results demonstrated that the SOC mineralization rate of soils dominated by graded aggregates were significantly different, indicating that SOC mineralization in eroded and deposited environments are shaped by selective transport of water erosion. The highest mineralization rate was found in soils containing 1-2 mm aggregates at the initial stage of the experiment, and the daily average mineralization rate of the < 0.5 mm aggregates was significantly higher than that of the 2-3 mm aggregates. During the incubation, fungal communities exhibited a low dynamic character, whereas the composition of bacterial communities in all treatments changed significantly and had obvious differences relative to each other. Bacterial species diversities and relative abundances in the <0.5mm and the 2-3mm aggregates showed opposite dynamic characteristics. However, there were no statistical interactions between the dynamics of microbial communities and the changes of SOC or soil water content. Changes in bacterial community structure had no significant impact on the mineralization of SOC, which might be related to the quality of SOC or the specific utilization of carbon sources by different functional groups of microorganisms. Mineralization of the eroded and retained SOCs with specific qualities in relation to their functional microorganisms should be further explored in the future.

scholarly journals Isotope Analysis Reveals Differential Impacts of Artificial and Natural Afforestation On Soil Organic Carbon Dynamics in Abandoned Farmland

2021 ◽  
Author(s):  
Dongrui Di ◽  
Guangwei Huang
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Size ◽  
Plant Residues ◽  
Significant Difference ◽  
Land Use System ◽  
Time Substitution ◽  
Soc Stocks

Abstract Backgrounds A multitude of studies have applied different methods to study the dynamics of soil organic carbon (SOC), but the differential impact of artificial and natural afforestation on SOC dynamic are still poorly understood. Methods and aims We investigated the SOC dynamics following artificial and natural afforestation in Loess Plateau of China, characterizing soil structure and stoichiometry using stable isotope carbon and radiocarbon models. We aim to compare SOC dynamics, clarify SOC source under different afforestation, examine comparability of the study areas and find how soil aggregate size classes control SOC dynamics, finally to evaluate effect of reforestation project.Results The 0-10cm and 10-20 cm SOC stocks were significant higher than other two land-use system. At other depths, there is no significant difference among the three land-use system. Total top soil SOC stocks, C:N and C:P of differently sized soil aggregates significantly increased following afforestation. 13C results and Radiocarbon models indicated that the SOC decomposition rate and new SOC input rate were lower under natural afforestation than artificial afforestation. Conclusions Afforestation can accumulate SOC in top soils mainly resulting from in topsoil changing. SOC resource is mainly from macroaggregate formation provided by fresh plant residues. SOC loss from soil respiration was derived from microaggregates during afforestation. The“space-for-time substitution” method is suitable for comparability of the study areas.

scholarly journals Soil organic carbon and iron oxides affects soil aggregate stability under straw returning and potassium fertilizer in a rice--rape cropping system

2022 ◽  
Author(s):  
Bin Xue ◽  
Li Huang ◽  
Jianwei Lu ◽  
Xiaokun Li ◽  
Ruili Gao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Iron Oxides ◽  
Soil Aggregates ◽  
Geometric Mean ◽  
Aggregate Stability ◽  
Cropping System ◽  
Potassium Fertilizer ◽  
Fe Oxides ◽  
Npk Fertilizer

Soil organic carbon (SOC) and iron (Fe) oxides are known to affect the formation and stability of soil aggregates. However, the effects of SOC and Fe oxides on soil aggregates stability under straw returning and potassium (K) fertilizer application in paddy–upland rotation systems are less well-studied. This study primarily investigated soil aggregates dynamics and their stability indices (mean weight diameter, MWD; geometric mean diameter, GMD), and soil binders (SOC and iron oxides) after rice and rape harvests under four treatments: F1，mineral nitrogen (N) and phosphorus (P) fertilizer; F2, mineral NPK fertilizer; F3, mineral NP fertilizer with straw returning; F4, mineral NPK fertilizer with straw returning in rice–rape cropping system. Straw returning treatments (F3 and F4) significantly (P <0.05) increased MWD and GMD, but the effect of K is not obvious. The soil aggregates stability was higher after the rape harvest than rice harvest, but SOC content was the opposite. Straw input can increase the contents of SOC, alkane-C and aromatic-C concentrations, especially in >0.25 mm aggregates. Long-term straw incorporation significantly increased the amorphous (Feo) and complex iron oxides (Fep) concentrations. SOC and Fep in bulk soil and >5 mm aggregates were significantly related with MWD, and significant relationship was observed between MWD and Feo in <5 mm fractions. Thus, the high levels of SOC, alkane-C, Feo and Fep in soil after straw returning were responsible for the aggregate stability, but the effect of potassium application is not obvious in a rice–rape cropping system.

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