scholarly journals Distribution of organic carbon fractions in soil aggregates in Chinese fir plantations with different stand ages

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xinxin He ◽  
Yongzhen Huang ◽  
Qianchun Zhang ◽  
Shaoming Ye ◽  
Shengqiang Wang

Abstract Background Revealing the variations in soil aggregate-related organic carbon (OC) and labile organic carbon (LOC) fractions in a chronosequence of Chinese fir plantations plays an important role in better understanding the impact of soil carbon sink or source on the Chinese fir plantation ecosystem. In this study, soil samples in a depth of 0–20 cm were collected from Chinese fir plantations at different stand ages (0, 9, 17, and 26 years old) in Guangxi, China. With the optimal moisture sieving method adopted, the soil aggregates of 4 different sizes were obtained, including > 2-mm, 2–1-mm, 1–0.25-mm, and < 0.25-mm aggregates. Soil OC and LOC fractions were measured in the aggregates of different sizes. The LOC fractions included readily oxidizable carbon (ROC), particulate organic carbon (POC), microbial biomass carbon (MBC), water-soluble organic carbon (WOC), and mineralized organic carbon (MOC). Results Soil aggregate stability, as indicated by the mean weight diameter (MWD), was the highest in the 17-year-old Chinese fir plantations and was significantly positively related (p < 0.05) to the concentrations of OC and LOC fractions (except for the ROC and MOC), with the POC in particular. As for all stand ages of Chinese fir plantations, the concentrations of soil OC and LOC fractions were significantly increased as the aggregate size decreased. Consequently, there were more OC and LOC fractions distributed in the < 0.25-mm aggregates. During the stand development, the concentrations of soil OC and LOC fractions first increased and then decreased, with the highest levels detected in the 17-year-old Chinese fir plantations, indicating that the 17-year-old Chinese fir plantations were conducive to the accumulation of soil OC and LOC fractions. Conclusion After 17 years of planting, promoted soil carbon (especially for the POC) accumulation contributes significantly to enhancing soil aggregate stability for the Chinese fir plantations in Guangxi, China.

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  

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.


2014 ◽  
Vol 955-959 ◽  
pp. 3566-3571 ◽  
Author(s):  
Yong Wang ◽  
Zhuang Xiong ◽  
Wu Xian Yan ◽  
Yue Qun Qiu

The objective of this study was to investigate soil aggregate stability within landscape on hillslopes by intensive tillage. Traditional tillage by consecutive hoeing was performed 5 and 20 times on steeply sloping land of the Sichuan Basin, China, by using the methods of simulated tillage to analyze the impact of long-term tillage on soil aggregates at different slope positions. The dry-sieved method was used to determine distribution of aggregate size in the different landscape positions, and mean weight diameter (MWD) and geometric mean diameter (GMD) as indices of soil aggregate stability. The different times of tillage resulted in different soil aggregate distributions. The results showed that the MWD and GMD values of aggregates were significantly decreased (p< 0.05) after 20-tillage operation, compared with pre-tillage operation. The differences in distributions of MWD and GMD demonstrate that the choice of the tillage times can be an important factor in changing soil aggregate stability and productivity in steeply sloping fields.


2019 ◽  
Vol 43 ◽  
Author(s):  
Marisângela Viana Barbosa ◽  
Daniela de Fátima Pedroso ◽  
Nilton Curi ◽  
Marco Aurélio Carbone Carneiro

ABSTRACT Soil structure, which is defined by the arrangement of the particles and the porous space forming aggregates, is one of the most important properties of the soil. Among the biological factors that influence the formation and stabilization of soil aggregates, arbuscular mycorrhizal fungi (AMF) are distinguished due to extrarradicular hyphae and glomalin production. In this context, the objective of this study was to evaluate different AMF (Acaulospora colombiana, Acaulospora longula, Acaulospora morrowiae, Paraglomus occultum and Gigaspora margarita) associated with Urochloa brizantha (A. Rich.) Stapf on soil aggregate stability. The study was conducted in a completely randomized design, using an Oxisol and autoclaved sand 2:1 (v/v), with seven treatments: five AMF; and treatments with plants without inoculation and with only the soil, with 5 replicates. The experiment was conducted during 180 days and the following variables were evaluated: mycelium total length (TML); production of easily extractable glomalin-related soil protein (GRSP) in the soil and aggregate classes; stability of the dry and immersed in water aggregates through the mean geometric diameter (MGD) and the mean weighted diameter (MWD) of aggregates; and the soil aggregate stability index (ASI). It was observed that the inoculation favored soil aggregation, with a high incidence of A. colombiana, which presented the highest MGD, TML and GRSP production in the aggregates with Ø>2.0mm and for A. colombiana and A. morrowiae in the aggregates with Ø<0.105 mm, when compared to the treatment without inoculation. These results show that there is a distinction between the effects of different AMF on the formation and stability of soil aggregates.


Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Radka Kodešová ◽  
Marcela Rohošková ◽  
Anna Žigová

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.


2021 ◽  
Vol 67 (No. 3) ◽  
pp. 173-181
Author(s):  
Yufei Liu ◽  
Xiaoxu Fan ◽  
Tong Zhang ◽  
Xin Sui ◽  
Fuqiang Song

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.  


2019 ◽  
Vol 23 (2) ◽  
pp. 27-36
Author(s):  
S Arofi ◽  
MM Rahman ◽  
HK Shiragi ◽  
MA Alam ◽  
MM Islam ◽  
...  

Soil aggregate is one of the vital indicators of soil health that depends on organic carbon (OC), texture and basic cations. A total of 206 soil samples were collected from 12 agro-ecological zones (AEZs) of Bangladesh to study the effects of organic carbon (OC), basic cations (Ca, Mg, K and Na) and different sized soil particles on soil aggregate stability. Soil samples were analyzed for bulk density, pH, OC, texture, basic cations and water stable soil aggregates (WSA) following standard protocols. Data revealed that OC positively increased WSA, while monovalent basic cations Na+ and K+ showed negative effects. Water stable soil aggregates and C stock of 0.25 mm sized soil fraction were found higher than that of larger sized soil fractions of 0.5, 1.0 and 2.0 mm. The roles of divalent basic cations Ca2+ and Mg2+ on WSA were found to be indistinct and need to be studied further. Ann. Bangladesh Agric. (2019) 23(2) : 27-36


Author(s):  
Man Liu ◽  
Guilin Han ◽  
Qian Zhang

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.


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