scholarly journals Impacts of Climate and Land Cover on Soil Organic Carbon in the Eastern Qilian Mountains, China

2019 ◽  
Vol 11 (20) ◽  
pp. 5790
Author(s):  
Junju Zhou ◽  
Dongxiang Xue ◽  
Li Lei ◽  
Lanying Wang ◽  
Guoshuang Zhong ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Soil Depth ◽  
Soil Layer ◽  
Qilian Mountains ◽  
Monthly Precipitation ◽  
Land Cover Types ◽  
The Mean

Soil, as the largest organic carbon pool of terrestrial ecosystem, plays a significant role in regulating the global carbon cycle, atmospheric carbon dioxide (CO2) levels, and global climate change. It is of great significance to scientifically understand the change rule and influence mechanism of soil organic carbon (SOC) to further understand the "source–sink" transformation of SOC and its influence on climate change. In this paper, the spatiotemporal distribution characteristics and influencing mechanism of SOC were analyzed by means of field investigation and laboratory analysis and the measured data in the Eastern Qilian Mountains. The results showed that the average SOC content of 0–50 cm was 35.74 ± 4.15 g/kg and the range of coefficients of variation (CV) between 48.84% and 75.84%, which suggested that the SOC content exhibited moderate heterogeneity at each soil layer of the Eastern Qilian Mountains. In four land cover types, the SOC content of forestland was the highest, followed by alpine meadow, grassland, and wilderness, which presented surface enrichment, and there was a decreasing trend with the soil depth. From the perspective of seasonal dynamics, there was a uniform pattern of SOC content in different land cover types, shown to be the highest in winter, followed by autumn, spring, and summer, and with the biggest difference between winter and summer appearing in the surface layer. At the same time, our study suggested that the SOC content of different land cover types was closely related to aboveground biomass and negatively related to both the mean monthly temperature and the mean monthly precipitation. Therefore, the distribution and variation of SOC was the result of a combination of climate, vegetation, and other factors.

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

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.

scholarly journals Whole-soil warming alters microbial community, but not concentrations of plant-derived soil organic carbon in subsoil

2021 ◽  
Author(s):  
Cyrill Zosso ◽  
Nicholas O.E. Ofiti ◽  
Jennifer L. Soong ◽  
Emily F. Solly ◽  
Margaret S. Torn ◽  
...  
Keyword(s):  
Climate Change ◽  
Microbial Community ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Depth ◽  
Global Climate ◽  
Plant Litter ◽  
Soil Warming ◽  
Four Seasons ◽  
Set Up

<p>Soils will warm in near synchrony with the air over the whole profiles following global climate change. It is largely unknown how subsoil (below 30 cm) microbial communities will respond to this warming and how plant-derived soil organic carbon (SOC) will be affected. Predictions how climate change will affect the large subsoil carbon pool (>50 % of SOC is below 30 cm soil depth) remain uncertain.</p><p>At Blodgett forest (California, USA) a field warming experiment was set up in 2013 warming whole soil profiles to 100 cm soil depth by +4°C compared to control plots. We took samples in 2018, after 4.5 years of continuous warming and investigated how warming has affected the abundance and community structure of microoganisms (using phospholipid fatty acids, PLFAs), and plant litter (using cutin and suberin).</p><p>The warmed subsoil (below 30 cm) contained significantly less microbial biomass (28%) compared to control plots, whereas the topsoil remained unchanged. Additionally below 50 cm, the microbial community was different in warmed as compared to control plots. Actinobacteria were relatively more abundant and Gram+ bacteria adapted their cell-membrane structure to warming. The decrease in microbial abundance might be related to lower SOC concentrations in warmed compared to control subsoils. In contrast to smaller SOC concentrations and less fine root mass in the warmed plots, the concentrations of the plant polymers suberin and cutin did not change. Overall our results demonstrate that already four seasons of simulated whole-soil warming caused distinct depth-specific responses of soil biogeochemistry: warming altered the subsoil microbial community, but not concentrations of plant-derived soil organic carbon.</p>

Stoichiometric characteristics of different agroecosystems under the same climatic conditions in the agropastoral ecotone of northern China

Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 875
Author(s):  
Xiajie Zhai ◽  
Kesi Liu ◽  
Deborah M. Finch ◽  
Ding Huang ◽  
Shiming Tang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Layer ◽  
Soil Nutrient ◽  
Northern China ◽  
Climatic Conditions ◽  
N:P Ratios ◽  
C:P Ratio ◽  
The Mean ◽  
Natural Grassland

Ecological stoichiometry affects the processes and functions of ecosystems, but the similarities and differences of stoichiometric characteristics among diverse agropastoral ecosystems under the same climatic conditions remain unclear. In this study, plant and soil stoichiometric characteristics of different agroecosystems, namely natural grassland (free-grazing and mowed grassland), artificial grassland (oat, Chinese leymus and corn silage), field crops (naked oats, flax and wheat) and commercial crops (cabbage and potatoes), were investigated in Guyuan County, China. Results showed total nitrogen (TN), total phosphorus (TP) and N:P ratios in plant tissue varied significantly among ecosystem types (P < 0.05). In general, the mean soil organic carbon, TN and TP content in the 0–0.3 m soil layer in potatoes (8.01, 1.05 and 0.33 g kg–1 respectively) were significantly lower than in other agroecosystems (P < 0.05). The mean C:N ratios of the 0–0.3 m soil layer did not differ significantly among the agroecosystems (P > 0.05). However, the C:P ratio was lower in potato than cabbage sites (24.64 vs 33.17), and was lower at both these sites than in other agroecosystems (P < 0.05). With regard to N:P ratios, only the potato ecosystem had lower values than in other ecosystems (P < 0.05), which did not differ significantly (P > 0.05). Above all, N is more likely to be limiting than P for biomass production in local agroecosystems. Soil C:P and N:P ratios decreased significantly with an increase in the utilisation intensity (from natural grassland to commercial crop). The findings of this study suggest that restoring, preserving and increasing soil organic carbon (especially for cabbage and potatoes), scientifically adjusting the application of N and P fertiliser and enhancing subsidies for low-loss soil nutrient systems, such as grassland, rather than commercial crops will help improve and sustain agroecosystems.

Variation in soil organic carbon mineralization under various land cover types in urban areas

2018 ◽  
Vol 38 (1) ◽  
Author(s):  
李隽永 LI Juanyong ◽  
窦晓琳 DOU Xiaolin ◽  
胡印红 HU Yinhong ◽  
甘德欣 GAN Dexin ◽  
李锋 LI Feng
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Urban Areas ◽  
Carbon Mineralization ◽  
Land Cover Types ◽  
Soil Organic Carbon Mineralization ◽  
Organic Carbon Mineralization

Spatial variability of soil organic carbon in the West Liao River Basin

2018 ◽  
Vol 64 (1-4) ◽  
pp. 25-34
Author(s):  
Yong-hua Zhu ◽  
Sheng Zhang ◽  
Biao Sun ◽  
Xiao-kang Xi ◽  
Yu Liu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Variability ◽  
Soil Depth ◽  
Soil Layer ◽  
Kriging Interpolation ◽  
Spherical Models ◽  
Basin Edge ◽  
Depth Increase

Quantification of the pattern and spatial distribution of soil organic carbon (SOC) is essential to comprehending many eco-hydrological processes. To obtain a better understanding of the spatial variability of SOC in a typical farming-pastoral zone, 270 soil samples were collected at 45 sampling sites from every 20 cm soil layer. Semi-variance function theory and ordinary Kriging interpolation were applied to identify the spatial variability of SOC. The results showed that SOC in the area was relatively low and decreased with depth and from the basin edge to the centre with a measured mean content of 0.07–0.65 g/kg. The strongest variability in the zone in the top soil layer (0–40 cm) was in the centre part of the zone, which was supposed to be the most concentrated area of human activities in the zone. As soil depth increase, the degree of variation of SOC decreased. Gaussian, exponential, and spherical models were suggested to successfully simulate SOC in different soil depth zones. The spatial distribution of SOC showed strong variability in the same soil depth zone, with a nugget to sill ratio of less than 14% and a range of 30–160 km.

scholarly journals Carbon storage in cocoa growing systems across different agroecological zones in Ghana

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
John Tennyson Afele ◽  
Evans Dawoe ◽  
Akwasi Adutwum Abunyewa ◽  
Victor Afari-Sefa ◽  
Richard Asare
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Depth ◽  
Forest Degradation ◽  
Carbon Stocks ◽  
Shade Trees ◽  
Collaborative Program ◽  
Agroecological Zones ◽  
Mitigate Climate Change

Shade grown cocoa systems have been credited with stocking high quantities of carbon and therefore possess the potential to mitigate climate change and help achieve targets of the United Nations Collaborative Program on Reduced Emissions from Deforestation and Forest Degradation (REDD+). This study quantifies and compares carbon stored as well as estimated cocoa yields in two shade management types (i.e., shaded and full sun) across three agroecological zones: Dry Semi-Deciduous Fire Zone (DSFZ), Moist Evergreen Zone (MEZ) and Upland Evergreen Moist Zone (UEMZ) in Ghana.  Results show that Soil organic carbon (SOC) stored decreased with increasing soil depth across all agroecological zones. Cocoa farms with shade trees stored 6 times more soil carbon (35.90±1.56 Mg C ha-1) compared to the full sun systems (5.98±1.56 Mg C ha-1). Carbon stocks in the DSFZ and the MEZ were 61.73±1.02 Mg C/ha and 67.46±1.02 Mg C ha-1 respectively whiles the UEMZ recorded 85.10 Mg C ha-1. Across agroecological zones, pod count in the UEMZ and the MEZ were similar but varied from that of the DSFZ, which recorded the least. Wilting of pods and cherrelles, was minimal and similar in the UMEZ and the MEZ but was significantly higher in the DSFZ. It is recommended that farmers should be encouraged through strong policies to adopt the integration of shade trees in the production of cocoa in Ghana to mitigate the effects of climate change.

scholarly journals Assessing Soil Organic Carbon Stock Dynamics under Future Climate Change Scenarios in the Middle Qilian Mountains

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1698
Author(s):  
Wei Liu ◽  
Meng Zhu ◽  
Yongge Li ◽  
Jutao Zhang ◽  
Linshan Yang ◽  
...  
Keyword(s):  
Climate Change ◽  
Machine Learning ◽  
Organic Carbon ◽  
Qilian Mountains ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Machine Learning Model ◽  
Soc Stock ◽  
The Mean

Soil organic carbon (SOC) simply cannot be managed if its amounts, changes and locations are not well known. Thus, evaluations of the spatio-temporal dynamics of SOC stock under future climate change are crucial for the adaptive management of regional carbon sequestration. Here, we evaluated the dynamics of SOC stock to a 60 cm depth in the middle Qilian Mountains (1755–5051 m a.s.l.) by combining systematic measurements from 138 sampling sites with a machine learning model. Our results reveal that the combination of systematic measurements with the machine learning model allowed spatially explicit estimates of SOC change to be made. The average SOC stock in the middle Qilian Mountains was expected to decrease under future climate change, while the size and direction of SOC stock changes seemed to be elevation-dependent. Specifically, in comparison with the 2000s, the mean annual precipitation was projected to increase by 18.37, 19.80 and 30.80 mm, and the mean annual temperature was projected to increase by 1.9, 2.4 and 2.9 °C under the Representative Concentration Pathway (RCP) 2.6 (low-emissions pathway), RCP4.5 (low-to-moderate-emissions pathway), and RCP8.5 (high-emissions pathway) scenarios by the 2050s, respectively. Accordingly, the area-weighted SOC stock and total storage for the whole study area were estimated to decrease by 0.43, 0.63 and 1.01 kg m–2 and 4.55, 6.66 and 10.62 Tg under the RCP2.6, RCP4.5 and RCP8.5 scenarios, respectively. In addition, the mid-elevation zones (3100–3900 m), especially the subalpine shrub-meadow Mollic Leptosols, were projected to experience the most intense carbon loss. However, the higher elevation zones (>3900 m), especially the alpine desert zone, were characterized by significant carbon accumulation. As for the low-elevation zones (<2900 m), SOC was projected to be less varied under future climate change scenarios. Thus, the mid-elevation zones, especially the subalpine shrub-meadows and Mollic Leptosols, should be given priority in terms of reducing CO2 emissions in the Qilian Mountains.

scholarly journals Effect of Grazing Management and Land Cover Types on Mineral-Associated Organic Carbon and Particulate Organic Carbon in a Semi-arid Rangelands in Kenya

2021 ◽  
Author(s):  
Angela Nduta Gitau ◽  
R.N. Onwonga ◽  
J. S. Mbau ◽  
J. Chepkemoi ◽  
S. M. Mureithi
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Land Cover ◽  
Particulate Organic Carbon ◽  
Grazing Management ◽  
Bare Ground ◽  
Land Cover Types ◽  
Continuous Grazing ◽  
Arid Rangelands ◽  
Semi Arid

Abstract BackgroundEnhancing soil organic carbon storage in areas under extensive livestock grazing has become a challenge in most arid and semi-arid rangelands in Sub-Saharan Africa. In Kenya for instance, continuous unplanned grazing in community lands has led to overgrazing and degradation of the rangelands. For decades, livestock production has shaped the landscape through various management practices. Grazing can be used to increase soil organic carbon (SOC) content but intensive use of land can lead to its depletion. This study was set out to elucidate the effect of two types of grazing management under varying land cover types on mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) in the soil. The study was carried out in two ranches, Mpala Research Centre (controlled grazing) and Ilmotiok Community Group Ranch (continuous grazing). The experimental design was a completely randomized block design in split-plot arrangement with three replicates. The main plots were the grazing practices; (controlled grazing and continuous grazing); and sub-plots were the land cover types: (bare ground, patches of grasses, and mosaics of trees). These treatments were randomly selected and replicated three times. Three topographical positions (mid-slope, foot slope and bottom land) were used as a blocking factor.ResultsThe interaction had no significant effect on MAOC fraction in any soil depth interval. Controlled grazed zones significantly recorded higher organic carbon content (POC= 0.887% CC SD=0.49) compared to zones under continuous grazing (POC = 0.718% CC SD=0.3). Mosaic of trees (POC =1.15% CC, SD = 0.22) recorded the highest concentration of carbon followed by patches of grass (POC = 0.87% CC, SD= 0.37) and bare ground (POC = 0.38% CC SD = 0.12) had the least.ConclusionThis study shows that grazing practices as well as land cover types have a significant effect on POC but not on MAOC. Mosaic of trees under controlled grazing has higher POC whereas bareground under continuous grazing had the least POC. Destocking should be done under continuous grazed zones to reduce further loss of POC and MAOC and allow vegetation recovery.

Soil organic carbon dynamics as affected by climate warming in a semiarid alpine region

2020 ◽  
Author(s):  
Meng Zhu ◽  
Wei Liu ◽  
Qi Feng ◽  
Bing Jia ◽  
Chengqi Zhang
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Climate Warming ◽  
Qilian Mountains ◽  
Carbon Accumulation ◽  
Future Climate ◽  
Future Climate Change ◽  
Alpine Regions ◽  
Soc Stock ◽  
The Mean

&lt;p&gt;An evaluation to soil organic carbon (SOC) stock dynamics in alpine regions is crucial for the&amp;#160;adaptive&amp;#160;management of regional carbon budget under the elevation-dependent warming in mountainous regions. Here, we evaluated the dynamics of SOC stock to 60 cm depth in the Qilian Mountains (1700~5100 m a.s.l.) by combining systematic measurements from 138 sampling sites with a machine learning technique (i.e. random forest, RF). Our results revealed that the combination of systematic measurements with the RF model allowed spatially explicit estimates to be made. The average SOC density (SOC amount per unit area, SOCD) in the middle Qilian Mountains will decrease under future climate change. However, the size and direction of carbon change are elevation- or vegetation-dependent. Specifically, in comparison with the baseline year (1970~2000), the mean annual precipitation will increase by 18.37, 19.80 and 30.80 mm, and the mean annual temperature will increase by 1.9, 2.4 and 2.9&amp;#176;C, respectively, under the RCP2.6 (representative concentration pathway), RCP4.5 and RCP8.5 scenarios in 2050s. Accordingly, the mean SOCD decreased by 0.59, 0.93 and 1.05 kg C m&lt;sup&gt;-2&lt;/sup&gt;, the SOC stock decreased by 6.23, 9.75 and 11.07 Tg C, respectively under the RCP2.6, RCP4.5 and RCP8.5 scenarios. In addition, the mid-elevation zones (3100-3900 m), especially the subalpine shrub-meadow zone, will be characterized by the strongest carbon loss due to the high standing organic carbon stock under climate warming. By contrast, the high elevation zones (&gt; 3900 m), especially the alpine desert zone, which will experience increase in accumulative temperature, prolongation in growing season, and consequently enhancement in plant productivity due to future climate warming, will be characterized by significant carbon accumulation in the future. Thus, the mid-elevation zones, especially the subalpine shrub-meadow zone should be given priority in terms of reducing CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;emissions under future warming in alpine regions.&lt;/p&gt;

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