Soil organic carbon stocks under different páramo vegetation covers in Ecuador’s northern Andes

Author(s):  
Marlon Calispa ◽  
Raphaël van Ypersele ◽  
Benoît Pereira ◽  
Sebastián Páez-Bimos ◽  
Veerle Vanacker ◽  
...  

<p>The Ecuadorian páramo, a neotropical ecosystem located in the upper Andes, acts as a constant source of high-quality water. It also stores significant amounts of C at the regional scale. In this region, volcanic ash soils sustain most of the paramo, and C storage results partly from their propensity to accumulate organic matter. Vegetation type is known to influence the balance between plant C inputs and soil C losses, ultimately affecting the soil organic C (SOC) content and stock. Tussock-forming grass (spp. Calamagrostis Intermedia; TU), cushion-like plants (spp. Azorella pedunculata; CU) and shrubs and trees (Polylepis stands) are commonly found in the páramo. Our understanding of SOC stocks and dynamics in the páramo remains limited, despite mounting concerns that human activities are increasingly affecting vegetation and potentially, the capacity of these ecosystems to store C.</p><p>Here, we compare the organic C content and stock in soils under tussock-forming grass (spp. Calamagrostis Intermedia; TU) and soils under cushion-like plants (spp. Azorella pedunculata; CU). The study took place at Jatunhuayco, a watershed on the western slopes of Antisana volcano in the northern Ecuadorian Andes. Two areas of similar size (~0.35 km<sup>2</sup>) were surveyed. Fourty soil samples were collected randomly in each area to depths varying from 10 to 30 cm (A horizon) and from 30 to 75 cm (2Ab horizon). The soils are Vitric Andosols and the 2Ab horizon corresponds to a soil buried by the tephra fall from the Quilotoa eruption about 800 yr. BP. Sixteen intact soil samples were collected in Kopecky's cylinders for bulk density (BD) determination of each horizon.</p><p>The average SOC content in the A horizon of the CU sites (9.4±0.5%) is significantly higher (Mann-Whitney U test, p<0.05) than that of the TU sites (8.0±0.4%), probably reflecting a larger input of root biomass from the cushion-forming plants. The 2Ab horizon contains less organic C (i.e. TU: 4.3±0.3% and CU: 4.0±0.4%) than the A horizon, but the SOC contents are undistinguishable between the two vegetation types. This suggests that the influence of vegetation type on SOC is limited to the A horizon. The average SOC stocks (in the first 30 cm from the soil) for TU and CU are 20.04±1.1 and 18.23±1.0 kg/m<sup>2</sup>,<sup></sup>respectively. These values are almost two times greater than the global average reported for Vitric Andosols (~8.2 kg/m<sup>2</sup> ), but are lower than the estimates obtained for some wetter Andean páramos (22.5±5 kg/m<sup>2</sup>, 270% higher rainfall) from Ecuador. Our stock values further indicate that vegetation type has a limited effect on C storage in the young volcanic ash soils found at Jatunhuyaco. Despite a higher SOC content, the CU soils store a stock of organic C similar to that estimated for the TU soils. This likely reflects the comparatively lower BD of the former soils (650±100 vs. 840±30 kg/m<sup>3</sup>). Additional studies are needed in order to establish the vegetation-related factors driving the SOC content and stability in the TU and CU soils.</p>

2012 ◽  
Vol 42 (11) ◽  
pp. 1953-1964 ◽  
Author(s):  
Irene Fernandez ◽  
Juan Gabriel Álvarez-González ◽  
Beatríz Carrasco ◽  
Ana Daría Ruíz-González ◽  
Ana Cabaneiro

Forest ecosystems can act as C sinks, thus absorbing a high percentage of atmospheric CO2. Appropriate silvicultural regimes can therefore be applied as useful tools in climate change mitigation strategies. The present study analyzed the temporal changes in the effects of thinning on soil organic matter (SOM) dynamics and on soil CO2 emissions in radiata pine ( Pinus radiata D. Don) forests. Soil C effluxes were monitored over a period of 2 years in thinned and unthinned plots. In addition, soil samples from the plots were analyzed by solid-state 13C-NMR to determine the post-thinning SOM composition and fresh soil samples were incubated under laboratory conditions to determine their biodegradability. The results indicate that the potential soil C mineralization largely depends on the proportion of alkyl-C and N-alkyl-C functional groups in the SOM and on the microbial accessibility of the recalcitrant organic pool. Soil CO2 effluxes varied widely between seasons and increased exponentially with soil heating. Thinning led to decreased soil respiration and attenuation of the seasonal fluctuations. These effects were observed for up to 20 months after thinning, although they disappeared thereafter. Thus, moderate thinning caused enduring changes to the SOM composition and appeared to have temporary effects on the C storage capacity of forest soils, which is a critical aspect under the current climatic change scenario.


2016 ◽  
Vol 2 (4) ◽  
pp. 165-182 ◽  
Author(s):  
Chelsea L. Petrenko ◽  
Julia Bradley-Cook ◽  
Emily M. Lacroix ◽  
Andrew J. Friedland ◽  
Ross A. Virginia

Shrub species are expanding across the Arctic in response to climate change and biotic interactions. Changes in belowground carbon (C) and nitrogen (N) storage are of global importance because Arctic soils store approximately half of global soil C. We collected 10 (60 cm) soil cores each from graminoid- and shrub-dominated soils in western Greenland and determined soil texture, pH, C and N pools, and C:N ratios by depth for the mineral soil. To investigate the relative chemical stability of soil C between vegetation types, we employed a novel sequential extraction method for measuring organo-mineral C pools of increasing bond strength. We found that (i) mineral soil C and N storage was significantly greater under graminoids than shrubs (29.0 ± 1.8 versus 22.5 ± 3.0 kg·C·m−2 and 1.9 ± .12 versus 1.4 ± 1.9 kg·N·m−2), (ii) chemical mechanisms of C storage in the organo-mineral soil fraction did not differ between graminoid and shrub soils, and (iii) weak adsorption to mineral surfaces accounted for 40%–60% of C storage in organo-mineral fractions — a pool that is relatively sensitive to environmental disturbance. Differences in these C pools suggest that rates of C accumulation and retention differ by vegetation type, which could have implications for predicting future soil C pool storage.


2020 ◽  
Vol 29 (2) ◽  
pp. e009
Author(s):  
Cuong Levan ◽  
Hung Buimanh ◽  
Bolanle-Ojo Oluwasanmi Tope ◽  
Xiaoniu Xu ◽  
Thanh Nguyenminh ◽  
...  

Aim of the study: The major objective of this study was to estimate the biomass increment and carbon (C) storage of the main ecosystem components in an age-sequence of three Acacia mangium plantation stands.Area of study: Chang Riec Historical - Cultural Forest, Southeastern region, Vietnam.Material and methods: In order to assess the biomass of different tree components, 36 trees with diameter at breast height ranging from 13.38 to 22.87 cm were harvested from the different aged stands. Biomasses of understory (shrubs and herbs), and litter were also determined. Carbon storage in the trees and understory biomass, litter, and mineral soil (0-50 cm) were determined by analyzing the C content of each compartment.Main results: The biomass in trees, understory vegetation, litter, and ecosystem increased with stand age. Soil C represented 61.99% of the total, aboveground tree biomass C made up 26.73%, belowground tree biomass C accounted for 7.01%, and litter comprised 2.96%, whereas only a small amount (1.30%) was associated with understory vegetation. The average C content of total tree (47.97%) was higher than those of understory and litter. Soil organic C stock in the top 50 cm depth in 4-, 7- and 11-year-old stands of A. mangium were 86.86, 126.88 and 140.94 Mg. C ha-1 respectively. Soil C concentration decreased continually with increasing soil depth. Total C storage of three planted forests ranged from 131.36 to 255.86 Mg. C ha-1, of which 56.09 - 67.61% of C storage was in the soil and 26.88 - 40.40% in the trees.Research highlights: These results suggest that A. mangium is a promising afforestation tree species with fast growing, high biomass accumulation and high C sequestration potential.Keywords: Acacia mangium plantations; Biomass; Ecosystem carbon storage; Age-sequence; Vietnam.


Soil Research ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 894
Author(s):  
Parijat Saikia ◽  
Kushal Kumar Baruah ◽  
Satya Sundar Bhattacharya ◽  
Chandrima Choudhury

Soil organic carbon (C) management in agricultural fields can act improve soil health and productivity. However, reports on the C release pattern and the interactive effects of plant physiological parameters on soil C storage from subtropical regions of the world where rice is cultivated as a dominant food crop are inadequate. The interactions between plant metabolism, soil C storage, and organic-based nutrient management schemes have been little studied. Hence, a study was undertaken in rainfed winter rice to evaluate the effects of different levels of organics (crop residue (CR) and farmyard manure (FYM)) along with inorganic (NPK) inputs in an alluvial soil. The experiment was conducted in a typical humid subtropical climate in north-eastern India. The CR of the preceding rice crop (pre-monsoon) and cow dung based FYM were used as organic inputs for monsoon rice, which were applied in various combinations with inorganic fertilisers. We studied the influence of these selected nutrient management schemes on soil health attributes, C storage, and plant parameters. The highest gain in C storage (11.65%) was in soil under 80% NPK + CR (5 t ha–1) + FYM (10 t ha–1) treatment. Correspondingly, significant improvement (P < 0.05) in total C, dissolved organic C, and nitrogen availability in soil was evident under this treatment leading to augmentation of soil organic matter status and the net amount of sequestered C in soil after two years of rice cultivation. Such improvements resulted in greater flag leaf photosynthesis, biomass accumulation, and grain yield than the conventionally managed crops. Overall, this research showcases that organic-dominated nutrient management not only restored soil health but was also able to compensate 20% of the recommended NPK fertilisation without penalty on crop yield.


Author(s):  
Sulamirtes S. de A. Magalhaes ◽  
Fabricio T. Ramos ◽  
Oscarlina L. dos S. Weber

ABSTRACT Soil carbon (C) stock determination can subsidize discussions on the continuity of an agricultural management. This study aimed to evaluate the stocks of total organic C (STOC) and labile C (SLC), and the indices of C lability (CLI), C compartment (CCI) and C management (CMI), and correlate them with chemical and physical attributes of a Red Yellow Latosol (Oxisol) managed for 38 years with different tillage systems in a Cerrado region of Mato Grosso, Brazil. Disturbed and undisturbed soil samples were collected in three layers (0-0.05, 0.05-0.10 and 0.10-0.20 m). The CMI (CLI x CCI) showed higher STOC possibly as the tillage depth decreased, because none of the tillage systems conserved STOC and SLC in the layers of 0-0.05 and 0.05-0.10 m, compared with the Native Cerrado, i.e., soil C conservation only occurred in the layer of 0.10-0.20 m. Although the percentage of SLC in STOC was lower, only SLC was correlated with soil chemical and physical attributes and, based on the multiple linear regression analysis, SLC was explained in 54% (R2) by the cation exchange capacity and soil micropores. Therefore, for monitoring purposes, the SLCestimated can be useful to evaluate soil C storage.


2011 ◽  
Vol 8 (8) ◽  
pp. 2195-2208 ◽  
Author(s):  
A. Kammer ◽  
F. Hagedorn

Abstract. Very few field studies have quantified the different pathways of C loss from decomposing litter even though the partitioning of C fluxes is essential to understand soil C dynamics. Using 0.75 kg m−2 of 13C-depleted leaf (δ13C = −40.8 ‰) and 2 kg m−2 of twig litter (δ13C = −38.4 ‰), we tracked the litter-derived C in soil CO2 effluxes, dissolved organic C (DOC), and soil organic matter of a beech forest in the Swiss Jura. Autotrophic respiration was reduced by trenching. Our results show that mineralisation was the main pathway of C loss from decomposing litter over 1 yr, amounting to 24 and 31 % of the added twig and leaf litter. Contrary to our expectations, the leaf litter C was mineralised only slightly (1.2 times) more rapidly than the twig litter C. The leaching of DOC from twigs amounted to half of that from leaves throughout the experiment (2 vs. 4 % of added litter C). Tracing the litter-derived DOC in the soil showed that DOC from both litter types was mostly removed (88–96 %) with passage through the top centimetres of the mineral soil (0–5 cm) where it might have been stabilised. In the soil organic C at 0–2 cm depth, we indeed recovered 4 % of the initial twig C and 8 % of the leaf C after 1 yr. Much of the 13C-depleted litter remained on the soil surface throughout the experiment: 60 % of the twig litter C and 25 % of the leaf litter C. From the gap in the 13C-mass balance based on C mineralisation, DOC leaching, C input into top soils, and remaining litter, we inferred that another 30 % of the leaf C but only 10 % of twig C could have been transported via soil fauna to soil depths below 2 cm. In summary, over 1 yr, twig litter was mineralised more rapidly relative to leaf litter than expected, and much less of the twig-derived C was transported to the mineral soil than of the leaf-derived C. Both findings provide some evidence that twig litter could contribute less to the C storage in these base-rich forest soils than leaf litter.


2012 ◽  
Vol 9 (1) ◽  
pp. 1055-1096 ◽  
Author(s):  
A. M. G. De Bruijn ◽  
P. Calanca ◽  
C. Ammann ◽  
J. Fuhrer

Abstract. We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system where fertilization is omitted and harvests are fewer. The Oensingen Grassland Model was explicitly developed for this study. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001–2100 under three climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 yr after grassland establishment. Differences in SOC between climate scenarios become significant after 20 yr and climate effects dominate SOC dynamics from approximately 50 yr after establishment, (2) carbon supplied through manure contributes about 60% to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10 cm soil until 5 yr after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under ley-arable rotation and with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems.


2010 ◽  
Vol 7 (2) ◽  
pp. 1575-1602 ◽  
Author(s):  
Y. Carrillo ◽  
E. Pendall ◽  
F. A. Dijkstra ◽  
J. A. Morgan ◽  
J. M. Newcomb

Abstract. Elevated CO2 generally increases soil C pools. However, greater available C concentrations can potentially stimulate soil organic matter (SOM) decomposition. The effects of climate warming on C storage can also be positive or negative. There is a high degree of uncertainty on the combined effects of climate warming and atmospheric CO2 increase on SOM dynamics and its potential feedbacks to climate change. Semi-arid systems are predicted to show strong ecosystem responses to both factors. Global change factors can have contrasting effects for different SOM pools, thus, to understand the mechanisms underlying the combined effects of multiple factors on soil C storage, effects on individual C pools and their kinetics should be evaluated. We assessed SOM dynamics by conducting long-term laboratory incubations of soils from PHACE (Prairie Heating and CO2 Enrichment experiment), an elevated CO2 and warming field experiment in semi-arid, native northern mixed grass prairie, Wyoming, USA. We measured total C mineralization and estimated the size of the labile pool and the decomposition rates of the labile and resistant SOM pools. To examine the role of plant inputs on SOM dynamics we measured aboveground biomass, root biomass, and soil dissolved organic C (DOC). Greater aboveground productivity under elevated CO2 translated into enlarged pools of readily available C (measured as total mineralized C, labile C pool and DOC). The effects of warming on the labile C only occurred in the first year of warming suggesting a transient effect of the microbial response to increased temperature. Experimental climate change affected the intrinsic decomposability of both the labile and resistant C pools. Positive relationships of the rate of decomposition of the resistant C with aboveground and belowground biomass and dissolved organic C suggested that plant inputs mediated the response by enhancing the degradability of the resistant C. Our results contribute to a growing body of literature suggesting that priming is a ubiquitous phenomenon that should be included in C cycle models.


Author(s):  
Qianyi Wu ◽  
Kate A. Congreves

Farmers are looking for appropriate tools for assessing and interpreting the health status of their soils; however, there is no standardized and prairie-based soil health scoring framework. As such, we focused on developing one for arable cropping systems in Saskatchewan. In 2018, soil samples (0-15, 15-30, and 30-60 cm depths) were collected from 55 arable fields across Saskatchewan, along with native prairie samples. Various soil chemical, physical, and biological attributes were measured (23 attributes in total). Based on the data distribution for each attribute, we developed scoring functions. The results from multivariate analyses were used to determine the weighting factors needed to integrate the individual scores from each soil attribute into a single Saskatchewan Assessment of Soil Health (SASH) score. Soil C and N indices (soil organic C, active C, total N, and soil protein) and total P produced the highest weighting factors. We also tested if there were linkages between the soil health and crop productivity by assessing the cereal yields for the past 10 years as reported from the same rural municipalities where the soil samples were collected. A positive relationship between soil health and yields was most apparent during dry years; thus, we recommend further research to explore this linkage at a finer-scale. Overall, this research forms the foundation of a promising framework that can be built upon, and in due course, lead to the development of a tool for producers who are interested in tracking soil health and using the results to inform management.


2013 ◽  
Vol 37 (3) ◽  
pp. 784-795 ◽  
Author(s):  
José Augusto Amorim Silva do Sacramento ◽  
Ana Caroline de Moraes Araújo ◽  
Maria Eugenia Ortiz Escobar ◽  
Francisco Alisson da Silva Xavier ◽  
Ana Clara Rodrigues Cavalcante ◽  
...  

In the semiarid region of Brazil, inadequate management of cropping systems and low plant biomass production can contribute to reduce soil carbon (C) and nitrogen (N) stocks; therefore, management systems that preserve C and N must be adopted. This study aimed to evaluate the changes in soil C and N stocks that were promoted by agroforestry (agrosilvopastoral and silvopastoral) and traditional agricultural systems (slash-and-burn clearing and cultivation for two and three years) and to compare these systems with the natural Caatinga vegetation after 13 years of cultivation. The experiment was carried out on a typical Ortic Chromic Luvisol in the municipality of Sobral, Ceará, Brazil. Soil samples were collected (layers 0-6, 6-12, 12-20, 20-40 and 40-60 cm) with four replications. The plain, convex and concave landforms in each study situation were analyzed, and the total organic C, total N and densities of the soil samples were assessed. The silvopastoral system promoted the greatest long-term reductions in C and N stocks, while the agrosilvopastoral system promoted the smallest losses and therefore represents a sustainable alternative for soil C and N sequestration in these semiarid conditions. The traditional agricultural system produced reductions of 58.87 and 9.57 Mg ha-1 in the organic C and total N stocks, respectively, which suggests that this system is inadequate for these semiarid conditions. The organic C stocks were largest in the concave landform in the agrosilvopastoral system and in the plain landform in the silvopastoral system, while the total N values were highest in the concave landform in the native, agrosilvopastoral and silvopastoral systems.


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