A method for measuring above- and below-ground C stocks in hillside landscapes

2005 ◽  
Vol 85 (Special Issue) ◽  
pp. 523-530 ◽  
Author(s):  
C. M. Monreal ◽  
J. D. Etchevers ◽  
M. Acosta ◽  
C. Hidalgo ◽  
J. Padilla ◽  
...  

Information on C stocks in agriculture and forest ecosystems in hillside landscapes is limited. The objective of this study was to develop and test field methods to measure above- and below-ground C stocks in hillside landscapes. Above-ground biomass in agricultural system was determined by measuring weight of residues left after crop harvest. In degraded secondary forests, tree biomass was estimated using allometric equations developed from in situ measurements. Herbs + bushes and litter dry weight were measured in two 0.25-m2 quadrats located within one 100-m2 treed plots. Carbon stocks were determined after chemical analysis of plant tissue and soil samples by dry combustion. Geo-referenced cores were taken inside a 1-m-diameter soil sampling clock that allows for spatial and temporal monitoring of soil C changes. The clock was marked with 12 divisions to establish the exact location of present and future sampling points. The below-ground fraction of C (mineral soil and fine roots) amounted to nearly 95% of the total C stock in agricultural systems and between 57 and 82% in the case of forest systems. Soil C stocks in hillside agricultural soils were higher than those found in forested soils with 70% of the C stored below-ground residing in the 0–45 cm of soil. The field method detected differences in C stocks in pools associated with various vegetations and soils in hillside ecosystems. Key words: Soil carbon, belowground carbon, sampling clock, hillside agriculture, Mexico

2014 ◽  
Vol 44 (5) ◽  
pp. 476-486 ◽  
Author(s):  
Lisa J. Samuelson ◽  
Tom A. Stokes ◽  
John R. Butnor ◽  
Kurt H. Johnsen ◽  
Carlos A. Gonzalez-Benecke ◽  
...  

Longleaf pine (Pinus palustris Mill.) restoration in the southeastern United States offers opportunities for carbon (C) sequestration. Ecosystem C stocks are not well understood in longleaf pine forests, which are typically of low density and maintained by prescribed fire. The objectives of this research were to develop allometric equations for above- and below-ground biomass and quantify ecosystem C stocks in five longleaf pine forests ranging in age from 5 to 87 years and in basal area from 0.4 to 22.6 m2·ha−1. Live aboveground C (woody plant + ground cover) and live root C (longleaf pine below stump + plot level coarse roots + plot level fine roots) ranged from 1.4 and 2.9 Mg C·ha−1, respectively, in the 5-year-old stand to 78.4 and 19.2 Mg C·ha−1, respectively, in the 87-year-old stand. Total ecosystem C (live plant + dead organic matter + mineral soil) values were 71.6, 110.1, 124.6, 141.4, and 185.4 Mg C·ha−1 in the 5-, 12-, 21-, 64-, and 87-year-old stands, respectively, and dominated by tree C and soil C. In the 5-year-old stand, ground cover C and residual taproot C were significant C stocks. This unique, in-depth assessment of above- and below-ground C across a series of longleaf pine stands will improve estimates of C in longleaf pine ecosystems and contribute to development of general biomass models that account for variation in climate, site, and management history in an important but understudied ecosystem.


Soil Research ◽  
2006 ◽  
Vol 44 (2) ◽  
pp. 85 ◽  
Author(s):  
Neal A. Scott ◽  
Kevin R. Tate ◽  
Des J. Ross ◽  
Aroon Parshotam

Since 1992, afforestation with Pinus radiata D. Don in New Zealand has led to the establishment of over 600 000 ha of new plantation forests, about 85% of which are on fertile pastures used previously for grazing sheep and cattle. While this leads to rapid accumulation of carbon (C) in vegetation, the effects of afforestation on soil C are poorly understood. We examined key soil C cycling processes at the (former) Tikitere agroforestry experimental site near Rotorua, New Zealand. In 1973, replicated stands of P. radiata (100 and 400 stems/ha) were established on pastures, while replicated pasture plots were maintained throughout the first 26-year rotation. In 1996, soil C and microbial biomass C in 0–0.10 m depth soil, in situ soil respiration and net N mineralisation, and soil temperature were lower in the forest than in the pasture, and tended to decline with increasing tree-stocking density. In the 400 stems/ha stands, mineral soil C (0–0.50 m depth) was lower than in the pasture (104 and 126 Mg C/ha, respectively; P < 0.01). Carbon accumulation in the forest floor during the first rotation of these forest stands was 12 Mg C/ha. Using the Rothamsted soil C model (Roth-C), we examined how changes in plant C inputs following afforestation might lead to changes in soil C content to 0.30 m depth. Steady-state pasture inputs of 9.0 Mg C/ha.year were estimated using Roth-C; these C inputs were assumed to decrease linearly during the first 12 years following tree establishment (until canopy closure). Below-ground C inputs in the forest were estimated using steady-state relationships between litterfall and soil respiration; these inputs were assumed to increase linearly between years 1 and 12, after which they remained constant at 1.53 Mg C/ha.year until harvest. Measured changes in soil C (0−0.30 m) during the first rotation, in conjunction with the below-ground inputs, were used to estimate above-ground inputs (as a proportion of total litterfall [3.81 Mg C/ha.year]) to the soil. Our results suggest 10% of litterfall C over one rotation actually entered the mineral soil. Using these results and estimates of additional C inputs to the soil from harvest slash and weeds following harvest, we found mineral-soil C stocks would continue to decline during second and third rotations of P. radiata; the magnitude of this decline depended in part on how much slash enters the mineral soil matrix. We confirmed our modelling approach by simulating soil C changes to within 8% over 19 years following afforestation of pasture at another previously studied site, Purukohukohu. Whether afforestation leads to an increase or decrease in mineral-soil C may depend on previous pasture management; in highly productive pastures, high C inputs to the soil may maintain soil C at levels that cannot be sustained when trees are planted onto these grasslands.


Soil Research ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 83 ◽  
Author(s):  
W. E. Cotching

Soil carbon (C) stocks were calculated for Tasmanian soil orders to 0.3 and 1.0 m depth from existing datasets. Tasmanian soils have C stocks of 49–117 Mg C/ha in the upper 0.3 m, with Ferrosols having the largest soil C stocks. Mean soil C stocks in agricultural soils were significantly lower under intensive cropping than under irrigated pasture. The range in soil C within soil orders indicates that it is critical to determine initial soil C stocks at individual sites and farms for C accounting and trading purposes, because the initial soil C content will determine if current or changed management practices are likely to result in soil C sequestration or emission. The distribution of C within the profile was significantly different between agricultural and forested land, with agricultural soils having two-thirds of their soil C in the upper 0.3 m, compared with half for forested soils. The difference in this proportion between agricultural and forested land was largest in Dermosols (0.72 v. 0.47). The total amount of soil C in a soil to 1.0 m depth may not change with a change in land use, but the distribution can and any change in soil C deeper in the profile might affect how soil C can be managed for sequestration. Tasmanian soil C stocks are significantly greater than those in mainland states of Australia, reflecting the lower mean annual temperature and higher precipitation in Tasmania, which result in less oxidation of soil organic matter.


2014 ◽  
Vol 4 ◽  
Author(s):  
Jose Navarro Pedreño ◽  
Ignacio Gómez Lucas ◽  
Jose Martín Soriano Disla

The mineralisation of organic matter (OM) when sewage sludge was used as amendment in 70 contrasting agricultural soils from Spain was analysed. Soils received a single dose of sewage sludge (equivalent to 50t dry weight ha<sup>-1</sup>) and the O<sub>2</sub> consumption was continuously monitored for 30 days using a multiple sensor respirometer in a laboratory experiment. The cumulative O<sub>2</sub> consumption and rates after 8 and 30 days of incubation (O<sub>2 cum</sub> 8d, 30d and O<sub>2 rate</sub> 8d, 30d), the respiratory quotient (RQ), the maximum O<sub>2</sub> rates over the incubation period (O<sub>2 max</sub>) and time from the beginning of the incubation when O<sub>2 max</sub> occurred (T<sub>max</sub>), were determined in both amended and non-amended soils. Sewage sludge application resulted in increased values for O<sub>2 max</sub>, O<sub>2 rate</sub> 8d, and O<sub>2 cum</sub> 30d. Differences were minor for T<sub>max</sub>, RQ 8d and O<sub>2 rate</sub> 30d. A considerable amount of the initial OM applied was mineralised during the first 8 days. Organic matter decomposition (as expressed by O<sub>2 cum</sub> 30d) was favoured in soils with high values of pH, carbonates, soil organic carbon and low values of amorphous Mn. Soils with these characteristics may potentially lose soil C after sewage sludge application.


2018 ◽  
Vol 115 (11) ◽  
pp. 2776-2781 ◽  
Author(s):  
Lucas E. Nave ◽  
Grant M. Domke ◽  
Kathryn L. Hofmeister ◽  
Umakant Mishra ◽  
Charles H. Perry ◽  
...  

Soils are Earth’s largest terrestrial carbon (C) pool, and their responsiveness to land use and management make them appealing targets for strategies to enhance C sequestration. Numerous studies have identified practices that increase soil C, but their inferences are often based on limited data extrapolated over large areas. Here, we combine 15,000 observations from two national-level databases with remote sensing information to address the impacts of reforestation on the sequestration of C in topsoils (uppermost mineral soil horizons). We quantify C stocks in cultivated, reforesting, and natural forest topsoils; rates of C accumulation in reforesting topsoils; and their contribution to the US forest C sink. Our results indicate that reforestation increases topsoil C storage, and that reforesting lands, currently occupying >500,000 km2 in the United States, will sequester a cumulative 1.3–2.1 Pg C within a century (13–21 Tg C·y−1). Annually, these C gains constitute 10% of the US forest sector C sink and offset 1% of all US greenhouse gas emissions.


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.


2007 ◽  
Vol 87 (1) ◽  
pp. 93-102 ◽  
Author(s):  
J M Kranabetter ◽  
A M Macadam

The extent of carbon (C) storage in forests and the change in C stocks after harvesting are important considerations in the management of greenhouse gases. We measured changes in C storage over time (from postharvest, postburn, year 5, year 10 and year 20) in logging slash, forest floors, mineral soils and planted lodgepole pine (Pinus contorta var. latifolia) trees from six prescribed-burn plantations in north central British Columbia. After harvest, site C in these pools averaged 139 Mg ha-1, with approximately equal contributions from mineral soils (0–30 cm), forest floors and logging slash. Together these detrital pools declined by 71 Mg C ha-1, or 51% (28% directly from the broadcast burn, and a further 23% postburn), in the subsequent 20 yr. Postburn decay in logging slash was inferred by reductions in wood density (from 0.40 to 0.34 g cm-3), equal to an average k rate of 0.011 yr-1. Losses in forest floor C, amounting to more than 60% of the initial mass, were immediate and continued to year 5, with no reaccumulation evident by year 20. Mineral soil C concentrations initially fluctuated before declining by 25% through years 10 and 20. Overall, the reductions in C storage were offset by biomass accumulation of lodgepole pine, and we estimate these plantations had become a net sink for C before year 20, although total C storage was still less than postharvest levels. Key words: C sequestration, forest floors; coarse woody debris; soil organic matter


2020 ◽  
Author(s):  
Keyi He ◽  
Jiguang Feng ◽  
Biao Zhu

&lt;p&gt;Global changes can alter the quantity and quality of above-and below-ground inputs, which will affect soil carbon (C) dynamics and nutrient cycles. The effects of detritus from above- and below-ground are not entirely uniform. Although numerous experiments have been conducted, the general patterns of how litter manipulation affect soil biochemical processes and whether such effects varied among changes in above- and below-ground inputs remain unclear.&lt;/p&gt;&lt;p&gt;Here, we conducted a meta-analysis of 2181 observations from 216 published studies to examine the responses of belowground processes to manipulated above- and below-ground litter alterations.Our results showed that, across all studies, litter manipulation generally had significant effects on soil moisture, but had minor effects on soil temperature and pH. Litter addition generally stimulated C and nutrient cycle, and microbial variables, whereas removal of litter, root and both of them generally suppressed or did not change these processes. Specifically, litter addition significantly increased soil respiration (R&lt;sub&gt;s&lt;/sub&gt;) and soil organic carbon (SOC) content in the mineral soil by 24.5% and 6.2%, respectively. Litter removal, root removal, and no inputs (removal of both litter and root) reduced R&lt;sub&gt;s&lt;/sub&gt; by 23.6%, 38.1%, and 50.2%, respectively. Litter removal and no inputs on average decreased SOC content in the mineral soil by 19% and 22.8%, respectively, but such negative effect did not occur under root removal. This suggests that aboveground litter may be more valid in soil C stabilization than roots within a relatively short period. In addition, manipulation level also regulated the responses of SOC, R&lt;sub&gt;s&lt;/sub&gt; and MBC to litter alterations. The direction of litter manipulation effects on multiple variables are basically similar among ecosystem types.&lt;/p&gt;&lt;p&gt;Overall, our findings provide a reference for assessing the impact of primary productivity growth on C and nutrient cycling in terrestrial ecosystems under global changes, and highlight that the effects of aboveground litters and roots should be separately incorporated into soil C models.&lt;/p&gt;


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.


2007 ◽  
Vol 37 (11) ◽  
pp. 2260-2269 ◽  
Author(s):  
Anthony R. Taylor ◽  
Jian R. Wang ◽  
Han Y.H. Chen

Red spruce ( Picea rubens Sarg.) forests are an ecologically and economically important forest type in eastern Canada. We quantified the carbon (C) stocks of natural red spruce dominated stands in central Nova Scotia. Twenty-four stands over a 140 year chronosequence were sampled. Within each stand, major C pools including above- and below-ground tree biomass, shrub and herb vegetation, dead organic matter, and upper (0–10 cm) mineral soil were measured. A nonlinear four-parameter logistic function was fitted to the total site C stock data to describe the change in total ecosystem C storage over time. Total site C storage increased throughout stand development in a general sigmoidal pattern, increasing from 94.4 Mg C·ha–1 in the youngest age-class to a maximum of 247.0 Mg C·ha–1 in the 81- to 100-year-old age-class, then decreasing in the oldest age-classes. Carbon pools of live vegetation, standing dead trees, and downed woody debris displayed recognizable changes in C storage throughout stand development, conforming to some of the fundamental ideas on forest stand dynamics. Overall, above- and below-ground tree biomass had the greatest influence on total site C storage dynamics. These results are likely to be integrated into further forest management plans and generalized in other contexts to evaluate carbon stocks at the regional scale.


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