scholarly journals A Comparison of Soil Carbon Stocks of Intact and Restored Mangrove Forests in Northern Vietnam

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 660
Author(s):  
Pham Hong Tinh ◽  
Nguyen Thi Hong Hanh ◽  
Vo Van Thanh ◽  
Mai Sy Tuan ◽  
Pham Van Quang ◽  
...  

Background and Objectives: In northern Vietnam, nearly 37,100 hectares of mangroves were lost from 1964–1997 due to unsustainable harvest and deforestation for the creation of shrimp aquaculture ponds. To offset these losses, efforts in the late 1990s have resulted in thousands of hectares of mangroves being restored, but few studies to date have examined how effective these efforts are at creating restored mangrove forests that function similarly to the intact mangroves they are intended to replace. Materials and Methods: We quantified and compared soil carbon (C) stocks among restored (mono and mixed species) and intact mangrove forests in the provinces of Quang Ninh, Thai Binh, Nam Dinh and Thanh Hoa in northern Vietnam. A total of 96 soil cores up to a depth of 200 cm were collected every 25 m (25, 50, 75, 100, 125, and 150 m) along 16 linear transects that were 150 m long and perpendicular to the mangrove upland interface (six cores along each transect) at Quang Ninh (four transects), Thai Binh (five), Nam Dinh (four) and Thanh Hoa (three). Five-cm-long soil samples were then collected from the 0–15 cm, 15–30 cm, 30–50 cm, 50–100 cm, and >100 cm depth intervals of each soil core. Results: The study confirmed that the soil C stock of 20–25-year-old restored mangrove forest (217.74 ± 16.82 Mg/ha) was not significantly different from that of intact mangrove forest (300.68 ± 51.61 Mg/ha) (p > 0.05). Soil C stocks of Quang Ninh (323.89 ± 28.43 Mg/ha) were not significantly different from Nam Dinh (249.81 ± 19.09 Mg/ha), but both of those were significantly larger than Thai Binh (201.42 ± 27.65 Mg/ha) and Thanh Hoa (178.98 ± 30.82 Mg/ha) (p < 0.05). Soil C stock differences among provinces could be due to their different geomorphological characteristics and mangrove age. Soil C stocks did not differ among mangroves that were restored with mixed mangrove species (289.75 ± 33.28 Mg/ha), Sonneratia caseolaris (L.) Engl. (255.67 ± 13.11 Mg/ha) or Aegiceras corniculatum (L.) Blanco (278.15 ± 43.86 Mg/ha), but soil C stocks of those mangroves were significantly greater than that of Kandelia obovata Sheue, Liu & Yong (174.04 ± 20.38 Mg/ha) (p < 0.05). Conclusion: There were significant differences in the soil C stocks of mangrove forests among species and provinces in northern Vietnam. The soil C stock of 20–25-year-old restored mangrove forest was not significantly different from that of intact mangrove forest.

2020 ◽  
Author(s):  
David Lefebvre ◽  
Jeroen Meersmans ◽  
Guy Kirk ◽  
Adrian Williams

&lt;p&gt;Harvesting sugarcane (Saccharum officinarum) produces large quantities of biomass residues. We investigated the potential for converting these residues into biochar (recalcitrant carbon rich material) for soil carbon (C) sequestration. We modified a version of the RothC soil carbon model to follow changes in soil C stocks considering different amounts of fresh sugarcane residues and biochar (including recalcitrant and labile biochar fractions). We used Sao Paulo State (Brazil) as a case study due to its large sugarcane production and associated soil C sequestration potential.&lt;/p&gt;&lt;p&gt;Mechanical harvesting of sugarcane fields leaves behind &gt; 10 t dry matter of trash (leaves) ha&lt;sup&gt;-1&lt;/sup&gt; year&lt;sup&gt;-1&lt;/sup&gt;. Although trash blanketing increases soil fertility, an excessive amount is detrimental and reduces the subsequent crop yield. After the optimal trash blanketing amount, sugarcane cultivation still produces 5.9 t C ha&lt;sup&gt;-1&lt;/sup&gt; year&lt;sup&gt;-1&lt;/sup&gt; of excess trash and bagasse (processing residues) which are available for subsequent use.&lt;/p&gt;&lt;p&gt;The available residues could produce 2.5 t of slow-pyrolysis (550&amp;#176;C) biochar C ha&lt;sup&gt;-1&lt;/sup&gt; year&lt;sup&gt;-1&lt;/sup&gt;. The model predicts this could increase sugarcane field soil C stock on average by 2.4 &amp;#177; 0.4 t C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1&lt;/sup&gt;, after accounting for the climate and soil type variability across the State. Comparing different scenarios, we found that applying fresh residues into the field results in a smaller increase in soil C stock compared to the biochar because the soil C approaches a new equilibrium. For instance, adding 1.2 t of biochar C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; along with 3.2 t of fresh residue C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1 &lt;/sup&gt;increased the soil C stock by 1.8 t C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1 &lt;/sup&gt;after 10 years of repeated applications. In contrast, adding 0.62 t of biochar C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; with 4.5 t of fresh sugarcane residues C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1 &lt;/sup&gt;increased the soil carbon soil stock by 1.4 t C ha&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; year&lt;sup&gt;&amp;#8209;1&lt;/sup&gt; after 10 years of application. These are reductions 25% and 40% of the potential soil C accumulation rates compared with applying available residues as biochar.&amp;#160; &amp;#160;&lt;/p&gt;&lt;p&gt;We also tested the sensitivity of the model to biochar-induced positive priming (i.e. increased mineralization of soil organic C) using published values. This showed that the C sequestration balance remains positive over the long term, even considering an extremely high positive-priming factor. Upscaling our results to the total 5 Mha of sugarcane in Sao Paulo State, biochar application could sequester up to 50 Mt of CO&lt;sub&gt;2&lt;/sub&gt; equivalent per year, representing 31% of the emissions attributed to the State in 2016.&lt;/p&gt;&lt;p&gt;This study provides first insights into the sequestration potential of biochar application on sugarcane fields. Measurements of changes in soil C stocks in sugarcane field experiments are needed to further validate the model, and the emissions to implement the practice at large scale need to be taken into account. As the climate crisis grows, the need for greenhouse gas removal technologies becomes crucial. Assessing the net effectiveness of readily available technologies is essential to guide policy makers.&amp;#160;&amp;#160;&lt;/p&gt;


2018 ◽  
Vol 64 (No. 1) ◽  
pp. 1-6 ◽  
Author(s):  
Zhu Guangyu ◽  
Tang Zhuangsheng ◽  
Chen Lei ◽  
Shangguan Zhouping ◽  
Deng Lei

This study mainly estimates the effect of grazing on plant diversity and soil storages on the northern Loess Plateau of China. Four grazing intensities of ungrazed (UG), light (LG), moderate (MG), and heavy (HG) grassland were selected according to the vegetation utilization across the study area, in which plant diversity, heights, above- and belowground biomass, and soil carbon (C) stock were investigated. The results showed that overgrazing negatively affected plant growth and soil C stock. Plant cover, height, litter, above- and belowground productivity, as well as soil C stock significantly decreased with the increasing grazing intensity. Meanwhile, the UG and LG had higher grasses biomass together with lower forbs (P &lt; 0.01) compared with MG and HG. The abundance of dominating grasses species, such as Stipa bungeana and S. grandis were decreased through long-term grazing as grasses species are palatable for herbivores, and the dominating forbs species, such as Artemisia capillaries and Thymus mongolicus were significantly increased with increasing grazing intensities. The results indicated that grazing exclusion or light grazing had positive effects on the sustainable development of grassland ecosystems. Therefore, a balanced use and a long-term efficient management of grasslands were better measures to counteract their local degradations.


Author(s):  
Hao Zhang ◽  
Jianping Li ◽  
Yi Zhang ◽  
Yutao Wang ◽  
Juan Zhang ◽  
...  

Fencing for grazing exclusion and grazing are common land-use methods in the semi-arid areas of the Loess Plateau in China, which have been widely found to change grassland soil organic carbon (SOC); however empirical studies that evaluated driving factors of soil carbon (C) stocks under the different land use are still weak. In this study, we investigated soil physicochemical and soil respiration (Rs) in the fenced and grazed grassland, to study the soil C stock variations and the main driving mechanism of soil C accumulation. The results showed that bulk density (BD), soil moisture content (SMC), and soil porosity (SP) had no significant difference between fenced and grazed grassland. Fencing increased the SOC, total nitrogen (TN), and C/N ratio, and significantly increased the aboveground biomass (AGB), belowground biomass (BGB), and the amount of soil large macro-aggregates in the topsoil layer (0-10 cm), and the soil stability was improved. Meanwhile, grazing increased soil temperature (ST) and Rs. The soil C stock in the topsoil layer (0-10 cm) of fenced grassland was significantly higher than that of grazed grassland. The soil C/N ratio, BD, and MWD explained large proportions of the variations in soil C stocks. Our results indicate that fencing can improve the stability of soil structure, and reduce Rs, then increase soil C stocks, which is an effective way to improve soil C stocks of grassland ecological in semi-arid areas of northwest China.


2018 ◽  
Vol 73 ◽  
pp. 03006
Author(s):  
Dhita Prasisca Mutiatari ◽  
Rudhi Pribadi ◽  
Nana Kariada Tri Martuti

Mangrove ecosystem plays important role as carbon sink, not only on mangrove community but also on the top soil. The purposes of this research were 1) to estimates and compare C-stocks in vegetation and non-vegetation mangrove soils (represented by aquaculture ponds and mudflats); 2) modeling the spatial distribution of soil C-stocks in the study area. The purposive sampling method was used to determine 16 sample plots representing vegetation and non-vegetation mangroves. In each plot, the soil samples were taken on top soil layer (0-10 cm). For general display of spatial distribution maps of soil C-stocks, spatial interpolation is used by the Ordinary Kriging method. The result showed that total of soil C-stocks in coastal area of Trimulyo was 148.53 MgC ha-1, with composition of 53.59% in mangrove vegetation, 38.82% and 7.57% in cultivation pond and mudflat, respectively. Statistical analysis with ANOVA test showed no significant difference (ρ = 0.972) between soil C stock in vegetation and non-vegetation mangrove. It shows that the water column on the coast of Trimulyo has great potential as a carbon store.


2015 ◽  
Vol 12 (5) ◽  
pp. 1615-1627 ◽  
Author(s):  
J. D. M. Speed ◽  
V. Martinsen ◽  
A. J. Hester ◽  
Ø. Holand ◽  
J. Mulder ◽  
...  

Abstract. Treelines differentiate vastly contrasting ecosystems: open tundra from closed forest. Treeline advance has implications for the climate system due to the impact of the transition from tundra to forest ecosystem on carbon (C) storage and albedo. Treeline advance has been seen to increase above-ground C stocks as low vegetation is replaced with trees but decrease organic soil C stocks as old carbon is decomposed. However, studies comparing across the treeline typically do not account for elevational variation within the ecotone. Here we sample ecosystem C stocks along an elevational gradient (970 to 1300 m), incorporating a large-scale and long-term livestock grazing experiment, in the southern Norwegian mountains. We investigate whether there are continuous or discontinuous changes in C storage across the treeline ecotone, and whether these are modulated by grazing. We find that vegetation C stock decreases with elevation, with a clear breakpoint between the forest line and treeline above which the vegetation C stock is constant. C stocks in organic surface horizons of the soil were higher above the treeline than in the forest, whereas C stocks in mineral soil horizons are unrelated to elevation. Total ecosystem C stocks also showed a discontinuous elevational pattern, increasing with elevation above the treeline (8 g m−2 per metre increase in elevation), but decreasing with elevation below the forest line (−15 g m−2 per metre increase in elevation), such that ecosystem C storage reaches a minimum between the forest line and treeline. We did not find any effect of short-term (12 years) grazing on the elevational patterns. Our findings demonstrate that patterns of C storage across the treeline are complex, and should be taken account of when estimating ecosystem C storage with shifting treelines.


2005 ◽  
Vol 53 (7) ◽  
pp. 639 ◽  
Author(s):  
B. P. Harms ◽  
R. C. Dalal ◽  
A. P. Cramp

Changes in soil carbon (C) and nitrogen (N) stocks following tree clearing were estimated at 32 rangeland sites in central and southern Queensland by using paired-site sampling. When corrected for soil bulk-density differences at each site, average soil C across all sites decreased after tree clearing by 8.0% for 0–0.3-m soil depth, and by 5.4% for 0–1.0-m depth; there were corresponding declines in soil C of 2.5 and 3.5tha–1, respectively. Mean soil C stocks (excluding surface litter, extractable roots and coarse charcoal) at uncleared sites were 29.5tha–1 for 0–0.3-m soil depth, and 62.5tha–1 for 0–1.0-m depth. Mean soil C stocks (0–0.3m) were 41% of the mean total C for the soil–plant system (soil + litter/woody debris + stand biomass) at uncleared sites. Soil C decline (0–0.3m) accounted for approximately 7% of the average total C lost because of land clearing across all sites. Soil C stocks at uncleared sites were correlated with tree basal area, clay content and soil phosphorus (P) content. Changes in soil C after tree clearing were strongly correlated to initial soil C contents at the uncleared sites, and were associated with particular vegetation groups and soil types. Changes in soil N were strongly correlated with changes in soil C; however, the average change in soil N across all sites was not significant. Given the size of the C and N pools in rangeland soils, the factors that influence soil C and soil N dynamics in rangeland systems need to be better understood for the effective management of C stocks in these soils.


2012 ◽  
Vol 46 ◽  
pp. 1-9 ◽  
Author(s):  
Soh Sugihara ◽  
Shinya Funakawa ◽  
Method Kilasara ◽  
Takashi Kosaki

2014 ◽  
Vol 94 (2) ◽  
pp. 157-168 ◽  
Author(s):  
Caroline M. Preston ◽  
Charlotte E. Norris ◽  
Guy M. Bernard ◽  
David W. Beilman ◽  
Sylvie A. Quideau ◽  
...  

Preston, C. M., Norris, C. E., Bernard, G. M., Beilman, D. W., Quideau, S. A. and Wasylishen, R. E. 2014. Carbon and nitrogen in the silt-size fraction and its HCl-hydrolysis residues from coarse-textured Canadian boreal forest soils. Can. J. Soil Sci. 94: 157–168. Improving the capacity to predict changes in soil carbon (C) stocks in the Canadian boreal forest requires better information on the characteristics and age of soil carbon, especially more slowly cycling C in mineral soil. We characterized C in the silt-size fraction, as representative of C stabilized by mineral association, previously isolated in a study of soil profiles of four sandy boreal jack pine sites. Silt-size fraction accounted for 13–31% of the total soil C and 12–51% of the total soil N content. Solid-state 13C nuclear magnetic resonance spectroscopy showed that silt C was mostly dominated by alkyl and O,N-alkyl C, with low proportions of aryl C in most samples. Thus, despite the importance of fire in this region, there was little evidence of storage of pyrogenic C. We used HCl hydrolysis to isolate the oldest C within the silt-size fraction. Consistent with previous studies, this procedure removed 21–74% of C and 74–93% of N, leaving residues composed mainly of alkyl and aryl C. However, it failed to isolate consistently old C; 11 out of 16 samples had recent 14C ages (fraction of modern 14C > 1), although C-horizon samples were older, with Δ14C from –17 to –476‰. Our results indicate relatively young ages for C associated with the silt-size fractions in these sites, for which mineral soil C storage may be primarily limited by good drainage and coarse soil texture, exacerbated by losses due to periodic wildfire.


2018 ◽  
Vol 40 (2) ◽  
pp. 129-137
Author(s):  
Nguyen Hoang Hanh ◽  
Mai Sy Tuan ◽  
Pham Hong Tinh ◽  
Nguyen Thi Hong Hanh

Field surveys using unmanned aerial vehicle monitoring were conducted in combination with satellite image analysis to evaluate the characteristics of gaps inside mangrove forest vegetation in Dong Rui commune, Tien Yen district, Quang Ninh province as well as the natural regeneration inside these gaps. A total of 15 gaps was located in four survey plots totaling 22,500 m2, among which four different types of mangrove forest communities were found, being dominated by (1) Bruguiera gymnorrhiza; (2) Aegriceras corniculatum, Kandelia obovata, Rhizophora stylosa and Bruguiera gymnorrhiza; (3) Bruguiera gymnorrhiza, Rhizophora stylosa; and (4): Aegriceras corniculatum, Kandelia obovata, respectively. Based on observations from 2012 to 2018, changes in regenerated tree densities were similar between gaps with a poor diversity of 2–5 species resembling the composition of the surrounding canopy. In some gaps, species not found in the nearby vegetation were observed with lower densities. Thus, the regeneration and patching of the mangrove forest gaps in Dong Rui were quite uniform at a midium rate. Species composition inside gaps did not differ significantly from the surrounding magrove forest communities. However, the ecological dominance of each species varied over time, depending on several natural factors and human actitvities where gaps were formed..


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