scholarly journals Rebuilding soil organic C stocks in degraded grassland by grazing exclusion: a linked decline in soil inorganic C

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8986
Author(s):  
Yi Zhang ◽  
Yingzhong Xie ◽  
Hongbin Ma ◽  
Le Jing ◽  
Cory Matthew ◽  
...  

Background Our study evaluated how soil organic carbon (SOC) and soil inorganic carbon (SIC) recovered over time in deep loessial soil as overgrazed grassland was fenced and restored. Methods The study was conducted in the Yunwu Mountain Nature Reserve in the Ningxia Autonomous Region of China. In it we compared soil data from three grazed grassland (G) sites, three sites that were fenced for 15 years (F15), and three sites that were fenced for 30 years (F30) as a so-called ‘space for time series’. Results and Discussion We compared SOC accumulation in soil up to 200 cm below the surface in G, F15, and F30 plots. An increase in SOC correlated with a decrease in soil pH, and decreased soil bulk density. However, SOC sequestration in fenced plots was largely offset by a decrease in SIC, which was closely correlated (r = 0.713, p = 0.001) with SOC-driven soil pH decline. We observed no significant increase in soil total carbon in the F15 or F30 sites after comparing them to G. Conclusions Our data indicate that fencing causes the slow diffusion processes to intensify the soil property changes from increased litter return, and this slow diffusion process is still active 30 years after fencing at 100–200 cm soil depths in the studied deep loessial soil. These findings are likely applicable to similar sites.

2017 ◽  
Vol 5 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Kewat Sanjay Kumar ◽  

Mechanisms governing carbon stabilization in soils have received a great deal of attention in recent years due to their relevance in the global carbon cycle. Two thirds of the global terrestrial organic C stocks in ecosystems are stored in below ground components as terrestrial carbon pools in soils. Furthermore, mean residence time of soil organic carbon pools have slowest turnover rates in terrestrial ecosystems and thus there is vast potential to sequester atmospheric CO2 in soil ecosystems. Depending upon soil management practices it can be served as source or sink for atmospheric CO2. Sustainable management systems and practices such as conservation agriculture, agroforestry and application of biochar are emerging and promising tools for soil carbon sequestration. Increasing soil carbon storage in a system simultaneously improves the soil health by increase in infiltration rate, soil biota and fertility, nutrient cycling and decrease in soil erosion process, soil compaction and C emissions. Henceforth, it is vital to scientifically explore the mechanisms governing C flux in soils which is poorly understood in different ecosystems under anthropogenic interventions making soil as a potential sink for atmospheric CO2 to mitigate climate change. Henceforth, present paper aims to review basic mechanism governing carbon stabilization in soils and new practices and technological developments in agricultural and forest sciences for C sequestration in terrestrial soil ecosystems.


Author(s):  
Ziwei Xiao ◽  
Xuehui Bai ◽  
Mingzhu Zhao ◽  
Kai Luo ◽  
Hua Zhou ◽  
...  

Abstract Shaded coffee systems can mitigate climate change by fixation of atmospheric carbon dioxide (CO2) in soil. Understanding soil organic carbon (SOC) storage and the factors influencing SOC in coffee plantations are necessary for the development of sound land management practices to prevent land degradation and minimize SOC losses. This study was conducted in the main coffee-growing regions of Yunnan; SOC concentrations and storage of shaded and unshaded coffee systems were assessed in the top 40 cm of soil. Relationships between SOC concentration and factors affecting SOC were analysed using multiple linear regression based on the forward and backward stepwise regression method. Factors analysed were soil bulk density (ρb), soil pH, total nitrogen of soil (N), mean annual temperature (MAT), mean annual moisture (MAM), mean annual precipitation (MAP) and elevations (E). Akaike's information criterion (AIC), coefficient of determination (R2), root mean square error (RMSE) and residual sum of squares (RSS) were used to describe the accuracy of multiple linear regression models. Results showed that mean SOC concentration and storage decreased significantly with depth under unshaded coffee systems. Mean SOC concentration and storage were higher in shaded than unshaded coffee systems at 20–40 cm depth. The correlations between SOC concentration and ρb, pH and N were significant. Evidence from the multiple linear regression model showed that soil bulk density (ρb), soil pH, total nitrogen of soil (N) and climatic variables had the greatest impact on soil carbon storage in the coffee system.


Land ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 83
Author(s):  
Kelebohile Rose Seboko ◽  
Elmarie Kotze ◽  
Johan van Tol ◽  
George van Zijl

Soil organic carbon (SOC) is a crucial indicator of soil health and soil productivity. The long-term implications of rapid urbanization on sustainability have, in recent years, raised concern. This study aimed to characterize the SOC stocks in the Johannesburg Granite Dome, a highly urbanized and contaminated area. Six soil hydropedological groups; (recharge (deep), recharge (shallow), responsive (shallow), responsive (saturated), interflow (A/B), and interflow (soil/bedrock)) were identified to determine the vertical distribution of the SOC stocks and assess the variation among the soil groups. The carbon (C) content, bulk density, and soil depth were determined for all soil groups, and thereafter the SOC stocks were calculated. Organic C stocks in the A horizon ranged, on average, from 33.55 ± 21.73 t C ha−1 for recharge (deep) soils to 17.11 ± 7.62 t C ha−1 for responsive (shallow) soils. Higher C contents in some soils did not necessarily indicate higher SOC stocks due to the combined influence of soil depth and bulk density. Additionally, the total SOC stocks ranged from 92.82 ± 39.2 t C ha−1 for recharge (deep) soils to 22.81 ± 16.84 t C ha−1 for responsive (shallow) soils. Future studies should determine the SOC stocks in urban areas, taking diverse land-uses and the presence of iron (Fe) oxides into consideration. This is crucial for understanding urban ecosystem functions.


2017 ◽  
Vol 51 (10) ◽  
pp. 5630-5641 ◽  
Author(s):  
Raphael A. Viscarra Rossel ◽  
Craig R. Lobsey ◽  
Chris Sharman ◽  
Paul Flick ◽  
Gordon McLachlan

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Paloma Bescansa ◽  
Iñigo Virto ◽  
Oihane Fernández-Ugalde ◽  
María José Imaz ◽  
Alberto Enrique

The behaviour of earthworms, their role in organic matter incorporation into the soil, and the influence of aridity in such processes in arid and semiarid regions have scarcely been studied. In this study, physico-chemical analyses of the casts and the surrounding no-till agricultural soils of three experimental sites representing an aridity gradient in Navarre (NW Spain) were done. The casts were formed by the activity of the only anecic species,Scherotheca gigas(Dugès, 1828), ubiquitous in no-till soils in this region. We observed a significant depletion of clay and higher concentration of total organic C and labile C in the form of particulate organic matter (POM) in the casts as compared to the surrounding soil, suggesting selective ingestion of soil byS. gigas. This, together with the observation of increased concentration in POM with increasing aridity, suggests a major role of this species in the observed progressive gains of organic C stocks in no-till soils in the region.


2021 ◽  
Vol 11 (2) ◽  
pp. 750
Author(s):  
Roberta Pastorelli ◽  
Giuseppe Valboa ◽  
Alessandra Lagomarsino ◽  
Arturo Fabiani ◽  
Stefania Simoncini ◽  
...  

Digestate from biogas production can be recycled to the soil as conditioner/fertilizer improving the environmental sustainability of the energy supply chain. In a three-year maize-triticale rotation, we investigated the short-term effects of digestate on soil physical, chemical, and microbiological properties and evaluated its effectiveness in complementing the mineral fertilizers. Digestate soil treatments consisted of combined applications of the whole digestate and its mechanically separated solid fraction. Digestate increased soil total organic C, total N and K contents. Soil bulk density was not affected by treatments, while aggregate stability showed a transient improvement due to digestate treatments. A decrement of the transmission pores proportion and an increment of fissures was observed in digestate treated soils. Soil microbial community was only transiently affected by digestate treatments and no soil contamination from Clostridiaceae-related bacteria were observed. Digestate can significantly impair seed germination when applied at low dilution ratios. Crop yield under digestate treatment was similar to ordinary mineral-based fertilization. Overall, our experiment proved that the agronomic recycling of digestate from biogas production maintained a fair crop yield and soil quality. Digestate was confirmed as a valid resource for sustainable management of soil fertility under energy-crop farming, by combining a good attitude as a fertilizer with the ability to compensate for soil organic C loss.


2021 ◽  
Author(s):  
Mei Liu ◽  
Jia-Hao Wen ◽  
Ya-Mei Chen ◽  
Wen-Juan Xu ◽  
Qiong Wang ◽  
...  

Abstract Aims Plant-derived carbon (C) inputs via foliar litter, root litter and root exudates are key drivers of soil organic C stocks. However, the responses of these three input pathways to climate warming have rarely been studied in alpine shrublands. Methods By employing a three-year warming experiment (increased by1.3 ℃), we investigated the effects of warming on the relative C contributions from foliar litter, root litter and root exudates from Sibiraea angustata, a dominant shrub species in an alpine shrubland on the eastern Qinghai-Tibetan Plateau. Important Findings The soil organic C inputs from foliar litter, root litter and root exudates were 77.45, 90.58 and 26.94 g C m -2, respectively. Warming only slightly increased the soil organic C inputs from foliar litter and root litter by 8.04 and 11.13 g C m -2, but significantly increased the root exudate C input by 15.40 g C m -2. Warming significantly increased the relative C contributions of root exudates to total C inputs by 4.6% but slightly decreased those of foliar litter and root litter by 2.5% and 2.1%, respectively. Our results highlight that climate warming may stimulate plant-derived C inputs into soils mainly through root exudates rather than litter in alpine shrublands on the Qinghai-Tibetan Plateau.


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