scholarly journals Improved landscape partitioning and estimates of deep storage of soil organic carbon in the Zackenberg area (NE Greenland) using a geomorphological landform approach

Author(s):  
Juri Palmtag ◽  
Stefanie Cable ◽  
Hanne H. Christiansen ◽  
Gustaf Hugelius ◽  
Peter Kuhry

Abstract. This study aims to improve the previous soil organic carbon (SOC) and total nitrogen (TN) storage estimates for the Zackenberg area (NE Greenland) that were based on a land cover classification (LCC) approach, by using geomorphological upscaling. In addition, novel SOC estimates for deeper deposits (down to 300 cm depth) are presented. We hypothesize that landforms will better represent the long-term slope and depositional processes that result in deep SOC burial in this type of mountain permafrost environments. The updated mean SOC storage for the 0–100 cm soil depth is 4.8 kg C m−2, which is 42 % lower than the previous estimate of 8.3 kg C m−2 based on land cover upscaling. Similarly, the mean soil TN storage in the 0–100 cm depth decreased with 44 % from 0.50 kg (±0.1 CI) to 0.28 (±0.1 CI) kg TN m−2. We ascribe the difference to a previous areal overestimate of SOC and TN-rich vegetated land cover classes. The landform-based approach more correctly constrains the depositional areas in alluvial fans and deltas with high SOC and TN storage. These are also areas of deep carbon storage with an additional 2.4 kg C m−2 in the 100–300 cm depth interval. This research emphasizes the need to consider geomorphology when assessing SOC pools in mountain permafrost landscapes.

2018 ◽  
Vol 12 (5) ◽  
pp. 1735-1744 ◽  
Author(s):  
Juri Palmtag ◽  
Stefanie Cable ◽  
Hanne H. Christiansen ◽  
Gustaf Hugelius ◽  
Peter Kuhry

Abstract. Soils in the northern high latitudes are a key component in the global carbon cycle, with potential feedback on climate. This study aims to improve the previous soil organic carbon (SOC) and total nitrogen (TN) storage estimates for the Zackenberg area (NE Greenland) that were based on a land cover classification (LCC) approach, by using geomorphological upscaling. In addition, novel organic carbon (OC) estimates for deeper alluvial and deltaic deposits (down to 300 cm depth) are presented. We hypothesise that landforms will better represent the long-term slope and depositional processes that result in deep SOC burial in this type of mountain permafrost environments. The updated mean SOC storage for the 0–100 cm soil depth is 4.8 kg C m−2, which is 42 % lower than the previous estimate of 8.3 kg C m−2 based on land cover upscaling. Similarly, the mean soil TN storage in the 0–100 cm depth decreased with 44 % from 0.50 kg (± 0.1 CI) to 0.28 (±0.1 CI) kg TN m−2. We ascribe the differences to a previous areal overestimate of SOC- and TN-rich vegetated land cover classes. The landform-based approach more correctly constrains the depositional areas in alluvial fans and deltas with high SOC and TN storage. These are also areas of deep carbon storage with an additional 2.4 kg C m−2 in the 100–300 cm depth interval. This research emphasises the need to consider geomorphology when assessing SOC pools in mountain permafrost landscapes.


CATENA ◽  
2017 ◽  
Vol 151 ◽  
pp. 63-73 ◽  
Author(s):  
Samuel Bouchoms ◽  
Zhengang Wang ◽  
Veerle Vanacker ◽  
Sebastian Doetterl ◽  
Kristof Van Oost

2019 ◽  
Vol 11 (20) ◽  
pp. 5790
Author(s):  
Junju Zhou ◽  
Dongxiang Xue ◽  
Li Lei ◽  
Lanying Wang ◽  
Guoshuang Zhong ◽  
...  

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.


2014 ◽  
Vol 36 (4) ◽  
pp. 359 ◽  
Author(s):  
D. E. Allen ◽  
P. M. Bloesch ◽  
R. A. Cowley ◽  
T. G. Orton ◽  
J. E. Payne ◽  
...  

Fire and grazing are commonplace in Australian tropical savannas and the effects of these management practices on soil organic carbon stocks (SOC) is not well understood. A long-term (20 years) experiment studying the effects of fire on a grazed semi-arid tropical savanna was used to increase this understanding. Treatments, including frequency of fire (every 2, 4 and 6 years), season of fire [early (June) vs late (October) dry season] and unburnt control plots, were imposed on Vertosol grassland and Calcarosol woodland sites, which were grazed. Additionally long-term enclosures [unburnt (except the Calcarosol in 2001) and ungrazed since 1973] on each soil type adjacent to each site were sampled, although not included in statistical analyses. SOC stocks were measured to a soil depth of 0.3 m using a wet oxidation method (to avoid interference by carbonates) and compared on an equivalent soil mass basis. Significant treatment differences in SOC stocks were tested for, while accounting for spatial background variation within each site. SOC stocks (0–0.3 m soil depth) ranged between 10.1 and 28.9 t ha–1 (Vertosol site) and 20.7 and 54.9 t ha–1 (Calcarosol site). There were no consistent effects of frequency or season of fire on SOC stocks, possibly reflecting the limited statistical power of the study and inherent spatial variability observed. Differences in the response to frequency and season of fire observed between these soils may have been due to differences in clay type, plant species composition and/or preferential grazing activity associated with fire management. There may also have been differences in C input between treatments and sites due to differences in the herbage mass and post-fire grazing activity on both sites and changed pasture composition, higher herbage fuel load, and a reduction in woody cover on the Vertosol site. This study demonstrated the importance of accounting for background spatial variability and treatment replication (in the absence of baseline values) when assessing SOC stocks in relation to management practices. Given the absence of baseline SOC values and the potentially long period required to obtain changes in SOC in rangelands, modelling of turnover of SOC in relation to background spatial variability would enable management scenarios to be considered in relation to landscape variation that may be unrelated to management. These considerations are important for reducing uncertainty in C-flux accounting and to provide accurate and cost-effective methods for land managers considering participation in the C economy.


2009 ◽  
Vol 89 (4) ◽  
pp. 521-530 ◽  
Author(s):  
C D Baan ◽  
M C. J Grevers ◽  
J J Schoenau

A study was conducted to examine the effect of tillage on soil conditions and crop growth at three long-term (> 10 yr) no-till sites, one in each of the Brown, Black, and Gray soil zones of Saskatchewan. The four tillage treatments consisted of one cycle of tillage at three levels of intensity: spring cultivation only, fall + spring cultivation, and fall + spring + disc cultivation, all applied to no-till and also a no-till control. Total and particulate soil organic carbon, soil pH, and soil aggregation were not affected by the tillage operations. Tillage decreased the bulk density in the 5- to 10-cm soil depth, but did not affect soil water content (0-10 cm) or spring soil temperature (0-5 cm). Tillage decreased stratification of available phosphorus to some extent, but there appeared to be no associated effect on crop P uptake. Tillage did not effect crop production in any of the 3 yr following its imposition, except at one site where, in the first year, apparent tillage-induced nutrient immobilization resulted in lower yields. Overall, the imposition of one cycle of tillage on long-term no-till soils appears to have little effect on soil properties or crop growth.Key words: No-till, nutrient stratification, soil organic carbon, tillage


Resources ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 153 ◽  
Author(s):  
Elena A. Mikhailova ◽  
Garth R. Groshans ◽  
Christopher J. Post ◽  
Mark A. Schlautman ◽  
Gregory C. Post

Soil organic carbon (SOC) generates several ecosystem services (ES), including a regulating service by sequestering carbon (C) as SOC. This ES can be valued based on the avoided social cost of carbon (SC-CO2) from the long-term damage resulting from emissions of carbon dioxide (CO2). The objective of this study was to assess the value of SOC stocks, based on the avoided SC-CO2 ($42 per metric ton of CO2 in 2007 U.S. dollars), in the contiguous United States (U.S.) by soil order, soil depth (0–20, 20–100, 100–200 cm), land resource region (LRR), state, and region using information from the State Soil Geographic (STATSGO) database. The total calculated monetary value for SOC storage in the contiguous U.S. was between $4.64T (i.e., $4.64 trillion U.S. dollars, where T = trillion = 1012) and $23.1T, with a midpoint value of $12.7T. Soil orders with the highest midpoint SOC storage values were 1): Mollisols ($4.21T), 2) Histosols ($2.31T), and 3) Alfisols ($1.48T). The midpoint values of SOC normalized by area within soil order boundaries were ranked: 1) Histosols ($21.58 m−2), 2) Vertisols ($2.26 m−2), and 3) Mollisols ($2.08 m−2). The soil depth interval with the highest midpoint values of SOC storage and content was 20–100 cm ($6.18T and $0.84 m−2, respectively), while the depth interval 100–200 cm had the lowest midpoint values of SOC storage ($2.88T) and content ($0.39 m−2). The depth trends exemplify the prominence of SOC in the upper portions of soil. The LRRs with the highest midpoint SOC storage values were: 1) M – Central Feed Grains and Livestock Region ($1.8T), 2) T – Atlantic and Gulf Coast Lowland Forest and Crop Region ($1.26T), and 3) K – Northern Lake States Forest and Forage Region ($1.16T). The midpoint values of SOC normalized by area within LRR boundaries were ranked: 1) U – Florida Subtropical Fruit, Truck Crop, and Range Region ($6.10 m−2), 2) T – Atlantic and Gulf Coast Lowland Forest and Crop Region ($5.44 m−2), and 3) K – Northern Lake States Forest and Forage Region ($3.88 m−2). States with the highest midpoint values of SOC storage were: 1) Texas ($1.08T), 2) Minnesota ($834B) (i.e., $834 billion U.S. dollars, where B = billion = 109), and 3) Florida ($742B). Midpoint values of SOC normalized by area within state boundaries were ranked: 1) Florida ($5.44 m−2), 2) Delaware ($4.10 m−2), and 3) Minnesota ($3.99 m−2). Regions with the highest midpoint values of SOC storage were: 1) Midwest ($3.17T), 2) Southeast ($2.44T), and 3) Northern Plains ($2.35T). Midpoint values of SOC normalized by area within region boundaries were ranked: 1) Midwest ($2.73 m−2), 2) Southeast ($2.31 m−2), and 3) East ($1.82 m−2). The reported values and trends demonstrate the need for policies with regards to SOC management, which requires incentives within administrative boundaries but informed by the geographic distribution of SOC.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yacong Wu ◽  
Zhengcai Li ◽  
Caifang Cheng ◽  
Rongjie Liu

We conducted a study on a 48-year-oldCinnamomum camphoraplantation in the subtropics of China, by removing understory gradually and then comparing this treatment with a control (undisturbed). This study analyzed the content and storage soil organic carbon (SOC) in a soil depth of 0–60 cm. The results showed that SOC content was lower in understory removal (UR) treatment, with a decrease range from 5% to 34%, and a decline of 10.16 g·kg−1and 8.58 g·kg−1was noticed in 0–10 cm and 10–20 cm layers, respectively, with significant differences (P<0.05). Carbon storage was reduced in UR, ranging from 2% to 43%, with a particular drastic decline of 15.39 t·hm−2and 11.58 t·hm−2in 0–10 cm (P<0.01) and 10–20 cm (P<0.01) layers, respectively. Content of SOC had an extremely significant (P<0.01) correlation with soil nutrients in the two stands, and the correlation coefficients of CK were higher than those of UR. Our data showed that the presence of understory favored the accumulation of soil organic carbon to a large extent. Therefore, long-term practice of understory removal weakens the function of forest ecosystem as a carbon sink.


2014 ◽  
Vol 94 (3) ◽  
pp. 317-336 ◽  
Author(s):  
Katelyn A. Congreves ◽  
Jillian M. Smith ◽  
Deanna D. Németh ◽  
David C. Hooker ◽  
Laura L. Van Eerd

Congreves, K. A., Smith, J. M., Németh, D. D., Hooker, D. C. and Van Eerd, L. L. 2014. Soil organic carbon and land use: Processes and potential in Ontario’s long-term agro-ecosystem research sites. Can. J. Soil Sci. 94: 317–336. Soil organic carbon (SOC) is crucial for maintaining a productive agro-ecosystem. Long-term research must be synthesized to understand the effects of land management on SOC storage and to develop best practices to prevent soil degradation. Therefore, this review compiled an inventory of long-term Ontario studies and assessed SOC storage under common Ontario land management regimes via a meta-analysis and literature review. In general, greater SOC storage occurred in no-till (NT) vs. tillage systems, in crop rotation vs. continuous corn, and in N fertilizer vs. no N fertilizer systems; however, soil texture and perhaps drainage class may determine the effects of tillage. The effect on SOC storage was variable when deeper soil depth ranges (0–45 cm) were considered for NT and rotational cropping, which suggests an unpredictable effect of land management on SOC at depths below the plough layer. Therefore, researchers are encouraged to use the presented inventory of nine long-term research sites and 18 active experiments in Ontario to pursue coordinated studies of long-term land management on SOC at depths extending below the plough layer.


Soil Research ◽  
2010 ◽  
Vol 48 (5) ◽  
pp. 413 ◽  
Author(s):  
Subhadip Ghosh ◽  
Brian R. Wilson ◽  
Biswapati Mandal ◽  
Subrata K. Ghoshal ◽  
Ivor Growns

Soil organic carbon (SOC) constitutes a significant proportion of the terrestrial carbon (C) store and has a pivotal role in several physical, chemical, and biological soil processes that contribute to soil productivity and sustainability. Applications of inorganic and organic materials are management options that have the potential to increase SOC in agricultural systems. A study was conducted in 3 long-term fertility experiments (Barrackpur, Mohanpur, and Cuttack) on agricultural soils in the eastern cereal belt of India, to examine the effect of cultivation and the application of inorganic and organic amendments on total soil organic carbon (TOC) and on the proportions of soil C fractions at these sites. A supplementary aim of this study was to determine the suitability of the loss-on-ignition (LOI) method to routinely estimate SOC (Walkley and Black, WB) in this region by determining relationships and conversion factors between the WB and LOI techniques. Soil was sampled at 3 depths (0–0.15, 0.15–0.30, and 0.30–0.45 m) from 4 treatments (conventional cultivation, NPK, NPK+FYM, and fallow) of the experimental sites and analysed for TOC and various soil C pools. There were differences in the magnitude of TOC values among the sites. Conventional cultivation had the lowest TOC contents (148 t/ha) and NPK+FYM amended soils the largest (207 t/ha), with intermediate values in the other treatments. The non-labile or residual SOC fraction (Cfrac4) constituted the largest percentage of SOC under all treatments and varied from 35–49%. A higher proportion of the labile Cfrac1 fraction was observed under the fallow, whereas the proportion of Cfrac4 was significantly larger under NPK+FYM. There was a significant decrease in SOC with increasing soil depth. SOC decreased up to 17% at 0.15–0.30 m and declined a further 21% at 0.30–0.45 m. The more labile C fractions (Cfrac1, Cfrac2, Cfrac3) dominated in the near surface soil layers, but decreased significantly in the deeper layers to be dominated by Cfrac4 at 0.30–0.45 m depth. We also observed a strong correlation between the WB and LOI methods (calibrated for each soil) irrespective of soil depths and conclude that this might be a suitable method to estimate SOC where other techniques are not available. We conclude that fertiliser application and especially manure application have the potential to significantly increase SOC in agricultural soils.


2014 ◽  
Vol 18 (9) ◽  
pp. 3763-3775 ◽  
Author(s):  
K. Meusburger ◽  
G. Leitinger ◽  
L. Mabit ◽  
M. H. Mueller ◽  
A. Walter ◽  
...  

Abstract. Snow processes might be one important driver of soil erosion in Alpine grasslands and thus the unknown variable when erosion modelling is attempted. The aim of this study is to assess the importance of snow gliding as a soil erosion agent for four different land use/land cover types in a subalpine area in Switzerland. We used three different approaches to estimate soil erosion rates: sediment yield measurements in snow glide depositions, the fallout radionuclide 137Cs and modelling with the Revised Universal Soil Loss Equation (RUSLE). RUSLE permits the evaluation of soil loss by water erosion, the 137Cs method integrates soil loss due to all erosion agents involved, and the measurement of snow glide deposition sediment yield can be directly related to snow-glide-induced erosion. Further, cumulative snow glide distance was measured for the sites in the winter of 2009/2010 and modelled for the surrounding area and long-term average winter precipitation (1959–2010) with the spatial snow glide model (SSGM). Measured snow glide distance confirmed the presence of snow gliding and ranged from 2 to 189 cm, with lower values on the north-facing slopes. We observed a reduction of snow glide distance with increasing surface roughness of the vegetation, which is an important information with respect to conservation planning and expected and ongoing land use changes in the Alps. Snow glide erosion estimated from the snow glide depositions was highly variable with values ranging from 0.03 to 22.9 t ha−1 yr−1 in the winter of 2012/2013. For sites affected by snow glide deposition, a mean erosion rate of 8.4 t ha−1 yr−1 was found. The difference in long-term erosion rates determined with RUSLE and 137Cs confirms the constant influence of snow-glide-induced erosion, since a large difference (lower proportion of water erosion compared to total net erosion) was observed for sites with high snow glide rates and vice versa. Moreover, the difference between RUSLE and 137Cs erosion rates was related to the measured snow glide distance (R2 = 0.64; p < 0.005) and to the snow deposition sediment yields (R2 = 0.39; p = 0.13). The SSGM reproduced the relative difference of the measured snow glide values under different land uses and land cover types. The resulting map highlighted the relevance of snow gliding for large parts of the investigated area. Based on these results, we conclude that snow gliding appears to be a crucial and non-negligible process impacting soil erosion patterns and magnitude in subalpine areas with similar topographic and climatic conditions.


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