Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya
© Sheikh et al; licensee BioMed Central Ltd. 2009
Received: 30 December 2008
Accepted: 25 August 2009
Published: 25 August 2009
The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC). However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known.
This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora) and subtropical (Pinus roxburghii) forests, respectively.
The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation
Soils are the largest carbon reservoirs of the terrestrial carbon cycle. About three times more carbon is contained in soils than in the world's vegetation and soils hold double the amount of carbon that is present in the atmosphere. Worldwide the first 30 cm of soil holds 1500 Pg carbon ; for India the figure is 9 Pg . Soils play a key role in the global carbon budget and greenhouse effect . Soils contain 3.5% of the earth's carbon reserves, compared with 1.7% in the atmosphere, 8.9% in fossil fuels, 1.0% in biota and 84.9% in the oceans . The amount of CO2 in the atmosphere steadily increases as a consequence of anthropogenic emissions, but there is a large interannual variability caused by terrestrial biosphere .
The first estimate of the organic carbon stock in Indian soils was 24.3 pg (1 Pg = 1015 g) based on 48 soil samples . Forest soils are one of the major carbon sinks on earth, because of their higher organic matter content . Soils can act as sinks or as a source for carbon in the atmosphere depending on the changes happening to soil organic matter. Equilibrium between the rate of decomposition and rate of supply of organic matter is disturbed when forests are cleared and land use is changed [8, 9]. Soil organic matter can also increase or decrease depending on numerous factors, including climate, vegetation type, nutrient availability, disturbance, and land use and management practice [10, 11]. Physical soil properties, such as soil structure, particle size, and composition, have profound impact on soil carbon (C). Soil particle size has an influence on the rate of decomposition of soil organic carbon . The release of nutrients from litter decomposition is a fundamental process in the internal biogeochemical cycle of an ecosystem, and decomposers recycle a large amount of carbon that was bounded in the plant or tree to the atmosphere .
About 40% of the total SOC stock of the global soils resides in forest ecosystem . The Himalayan zones, with dense forest vegetation, cover nearly 19% of India and contain 33% of SOC reserves of the country . These forests are recognized for their unique conservation value and richness of economically important biodiversity. Managing these forests may be useful technique to increase soil carbon status because the presence of trees affects carbon dynamics directly or indirectly. Trees improve soil productivity through ecological and physicochemical changes that depend upon the quantity and quality of litter reaching soil surface and rate of litter decomposition and nutrient release .
The current global stock of soil organic carbon is estimated to be 1,500–1,550 Pg [1, 17, 18]. This constituent of the terrestrial carbon stock is twice that in the earth's atmosphere (720 Pg), and more than triple the stock of organic carbon in terrestrial vegetation (560 Pg) [19, 20]. To sustain the quality and productivity of soils, knowledge of SOC in terms of its amount and quality is essential. The first comprehensive study of organic carbon (OC) status in Indian soils was conducted  by collected 500 soil samples from different cultivated fields and forests with variable rainfall and temperature patterns. However, the study did not make any estimate of the total carbon reserves in the soils. The first attempt in estimating OC stock  was also made based on a hypothesis of enhancement of OC level on certain unproductive soils. In last decade, the greenhouse effect has been of great concern, and has led to several studies on the quality, kind, distribution and behaviour of SOC [23, 1, 24]. Global warming and its effect on soils in terms of SOC management have led to several quantitative estimates for global C content in the soils [23, 1, 24–26]. Although, so far the soil organic carbon stock studies in Indian Himalayan forests in relation to altitudinal gradient are not available. Therefore, the aim of the present study is made to estimate SOC stocks of two dominant forests of subtropical (Pinus roxburghii) and temperate (Quercus leucotrichophora) along altitudinal gradient in Garhwal Himalaya.
SOC (± SD) values at different depths of Quercus leucotrichophora forest soils
Soil depth (cm)
SOC g kg-1
24.3 ± 1.9
23.4 ± 3.4
21.9 ± 3.1
23.4 ± 0.8
22.5 ± 3.3
21.9 ± 1.2
22.5 ± 2.6
21.5 ± 6.8
16.5 ± 2.1
SOC (± SD) values at different depths in Pinus roxburghii forest soils
Soil depth (cm)
SOC g kg-1
18.0 ± 6.5
16.8 ± 4.1
12.1 ± 0.9
19.6 ± 0.9
11.2 ± 0.3
16.8 ± 5.3
18.0 ± 6.5
18.7 ± 8.4
15.0 ± 0.2
The maximum carbon stock was present in Quercus leucotrichophora forest soils. The higher percent of soil organic carbon in Quercus leucotrichophora forest may be due to dense canopy and higher input of litter which results in maximum storage of carbon stock. In Quercus leucotrichophora forest sites dense vegetation led to higher accumulation of soil organic carbon as compared to coniferous sites. In Pinus roxburghii forest, the lower amount of organic carbon might be due to wider spacing between trees, resulting in lower litter input and less accumulation, in turn yielding less storage of carbon stock in these forest soils.
Soil Organic Carbon stock (up to 60 cm depth) in Quercus leucotrichophora forest
SOC g kg-1
Carbon stock (t C ha-1)
23.2 ± 1.2
22.6 ± 0.7
20.1 ± 3.2
Soil Organic Carbon stock (up to 60 cm depth) in Pinus roxburghii Forest
Carbon stock (t C ha-1)
17.7 ± 0.24
15.8 ± 0.42
15.6 ± 0.31
The soil organic carbon (SOC) decreased with increasing soil depths in all the sites except site-II of the Pinus roxburghii forest, where organic carbon was highest in the top layer (0–20 cm) and lowest in middle depth (20–40 cm). In the Quercus leucotrichophora forest, for all sites (site-I, site-II and site-III) the level of soil organic carbon was higher in the upper layer, dropping with an increase in depth. The similar trend (higher in top layer and decreased with increasing depths) of soil organic carbon is also reported in the Pinus roxburghii. The higher organic carbon content in the top layer may be due to rapid decomposition of forest litter in a favorable environment. SOC represents  a significant pool of carbon within the biosphere. Climate shifts in temperature and precipitation have a major influence on the decompositions and amount of SOC stored within on ecosystem and that released into the atmosphere. The rate of cycling of carbon at different depths and in different pools across different vegetal cover is still not clear. There is not, as yet, enough information to predict how the size and residence time of different fractions of soil organic carbon varies . The higher concentration of soil organic carbon in top layer has also been reported by various authors [28, 29]. The steep fall in the SOC content as depth increases is an indication of higher biological activity associated with top layers. Our results are in accordance with earlier studies [28, 30].
The maximum carbon stock was present in Quercus leucotrichophora forest soils. The higher percent of soil organic carbon in Quercus leucotrichophora forest may be due to dense canopy and higher input of litter which results in maximum storage of carbon stock. In Quercus leucotrichophora forest sites dense vegetation led to higher accumulation of soil organic carbon as compared to coniferous sites. The higher accumulation of soil organic carbon found in maquis vegetation, as opposed to coniferous forest, has been reported by . In Pinus roxburghii forest, the lower amount of organic carbon might be due to wider spacing between trees, resulting in lower litter input and less accumulation, in turn yielding less storage of carbon stock in these forest soils. The study of  indicated a positive influence of residue application on soil carbon content. The added litter  and the proliferated root system  of the growing plants probably influenced the carbon storage in the soil, suggesting a positive correlation of SOC with the quantity of litter fall . The study  suggested that coarse and fine woody debris are substantial forest ecosystem carbon stock. The production and decay rate of forest woody detritus depends partially on climatic conditions. The results of this study indicated that highest carbon stock founding region with cool summer, while lower carbon in arid desert/steppes or temperate humid regions.
In Quercus leucotrichophora forest soils (Table 3), the maximum and minimum values of carbon stock was 185.6 t C ha-1 (site-I) and 160.8 t C ha-1 (site-III) respectively. The trend was similar for the Pinus roxburghii forest soils (Table 4), where the highest and lowest values of carbon stock was 141.6 t C ha-1 (site-I) and 124.8 t C ha-1 (site-III). A study of  recorded the following levels of organic carbon stored in some Indian soils: 41.2 t C ha-1, 120.4 t C ha-1, 13.2 t C ha-1, and 18 t C ha-1 in the Red soil, Laterite soil, Saline soil and Black soil respectively; all these measurements were lower than in the present study. Another study showed  the national average content of soil organic carbon was 182.94 t C ha-1. The total amount of soil organic carbon stored in Quercus leucotrichophora forest soils is almost similar to the national average and expresses the excellent ability of these forests to stock and sequester organic carbon. However, the total amount of organic carbon stored in Pinus roxburghii forest soils was lower than the national average.
A study carried of grassland in two different sites i.e., Mehrstedt and Kaltenborn, where SOC stocks at the clay rich Mehrstedt site were almost twice as high as at the sandy Kaltenborn site . The clay soil texture was contained on average 123 t C ha-1 for 0–60 cm depth. A compilation of 121 soil profiles of temperate grasslands, mainly from North America from several databases, resulted in a mean carbon stock of 91 t C ha-1 for 0–60 cm depth . However, the range of carbon stocks in temperate grasslands may be between 30 and 80 t C ha-1 . Soil organic matter (SOM) is a major component of global carbon cycle , increases with precipitation and decreases with temperature [42–44]. SOM content were also reported in the top 0–50 cm soil layer is positively correlated with the precipitation/temperature ratio in the Pampa and Chaco soils in Argentina .
While comparing the soil organic carbon stock values of different sites with each other in both forests, the carbon stock tended to decrease with increasing altitudes. A soil carbon study in Kathmandu valley of Nepal in Pinus roxburghii forest along altitudinal gradient at an elevation ranging between 1, 200 to 2,200 reported that the higher altitude soil was found to be much more depleted of C than the lower altitude soil . The decreasing trend of C might be attributed to the lower mineralization rate and net nitrification rate at the higher altitude. A study carried out  in Himalayan forests indicates a characteristic decline in total tree density and basal area was apparent with increasing altitude. In the present study, a characteristic decline in vegetation was observed across altitudinal strata and among sites. The decrease in species richness in high elevation strata could be due to eco-physiological constraints, low temperature and productivity . Altitude had a significant effect on species richness, which declines with even a 100 m increase in altitude. Species composition too is significantly affected by altitude . Altitude is often employed to study the effects of climatic variables on SOM dynamics [50, 44]. Temperature decreased and precipitation increased with increasing altitude. The changes in climate along altitudinal gradients influence the composition and productivity of vegetation and, consequently, affect the quantity and turnover of SOM [50, 51]. Altitude also influences SOM by controlling soil water balance, soil erosion and geologic deposition processes . The advantages of altitudinal gradients in forest soil for testing the effects of environmental variables on SOM dynamics is emphasized . The relationship between SOM and altitude has also been investigated and positive correlations were reported [53, 54]. A study of wetland, the balance between carbon input (organic matter production) and output (decomposition, methanogenisis, etc.) and the resulting storage of carbon depend on topography and the geological position of wetland; the hydrological regime; the type of plant present; the temperature and moisture of the soil; pH and the morphology . There is a strong relation between climate and soil carbon pools where organic carbon content decreases with increasing temperatures, because decomposition rates doubles with every 10°C increase in temperature .
The characteristic decline in vegetation with increasing altitude results in less accumulation of litter and low input of organic carbon in soils. Similar findings were also reported ; the number of trees per hectare decreases with increasing elevation, the comments related to kg ha-1 unquestionable give consequences implying that all weight parameters decreases at the altitude increases. A study carried out in the Western Ghats of southern India also shows the decline of soil organic carbon from 110.2 t C ha-1 at an elevation > 1400 m to 82.6 t C ha-1 at an elevation > 1800 m . The increasing tendency of carbon density with decreasing altitude may be better stabilization of SOC at lower altitudes. It is a proven fact that forest ecosystems are the best way to sequester carbon; however, considering the huge human population in developing country like India, much of the land cannot be spared for increase in forest cover. In such circumstance the management of vast areas of Himalayan forests at lower elevations can be regarded as major sinks of mitigating atmospheric carbon dioxide. Forests at higher altitudes can be seen as potential carbon sinks.
The study area is situated in Tehri Garhwal, one of the western-most districts of the Uttarakhand State, and located on the outer ranges of the mid-Himalayas, which comprise low line peaks rising directly from the plains of the northern India. The study site lies between 30° 18' 15.5" and 30° 20' 40" N latitude and 78° 40' 36.1" to 78° 37' 40.4" E longitude. Three sites were selected within Pinus roxburghii forest at an altitude of 700 m (site-I), 900 m (site-II), 1100 m asl (site-III) and three sites in Quercus leucotrichophora forest at altitudes of 1700 m (site-I), 1900 m (site-II) and 2100 m (site-III).
The quality of organic carbon data of the soils depends on sampling methods, the kind of vegetation, and the method of soil analysis performed in the laboratory. The sampling was done by nested plot design method. In each site, a plot of 100 × 20 m size was laid, and six sampling points were selected in each plot by the standard method . Three samples were collected at each sampling point at three depths (0–20, 20–40, 40–60 cm). A total of 108 soil samples (18 from each site) were collected by digging soil pits (6 × 3 × 6 cm). The soil samples were air dried and sieved (< 2 mm) before analysis. Soil organic carbon for various depths was determined by partial oxidation method . Soil samples from each depth were analysed, however to express the total SOC stock data in 0–20, 20–40, 40–60 cm, the weighted mean average were considered. The total SOC stock was estimated by multiplying the values of SOC g kg-1 by a factor of 8 million, based in the assumption that a layer of soil 60 cm deep covering an area of 1 ha weighs 8 million kg .
A comparison of the soil organic carbon stock values of different sites in both forests show that the carbon stock tonnes per hectare decrease with increasing altitudes. The tendency of carbon density to increase as altitude decreases may be due to better stabilization of SOC at lower altitudes. Considering the huge human population in developing country like India, much of the land cannot be spared for increase in forest cover. In such circumstance the management of vast areas of Himalayan forests at lower elevations can be regarded as major sinks of mitigating atmospheric carbon dioxide.
The authors are thankful to the reviewers and the Handling Editor for their constructive comments and suggestions.
- Batjes NH: Total C and N in soils of the world. Eur J Soil Sci 1996, 47: 151–163. 10.1111/j.1365-2389.1996.tb01386.xView ArticleGoogle Scholar
- Bhattacharya T, Pal DK, Mondal C, Velayutham M: Organic carbon stock in Indian soils and their geographical distribution. Current Science 2000,79(5):655–660.Google Scholar
- Jha MN, Gupta MK, Saxena A, Kumar R: Soil organic carbon store in different forests in India. Indian Forester 2003,129(6):714–724.Google Scholar
- Lal R, Kimble JM, Levines E, Whiteman C: World soil and greenhouse effect. SSSA Special Publication Number Madison, WI 1995, 57: 51–65.Google Scholar
- Erbrecht T, Lucht W: Impact of large scale climatic disturbances on the terrestrial carbon cycle. Carbon Balance and Management 2006, 1: 7. 10.1186/1750-0680-1-7View ArticleGoogle Scholar
- Gupta RK, Rao DLN: Potential of wastelands for sequestering carbon by reforestation. Current Science 1984, 66: 378–380.Google Scholar
- Dey SK: A preliminary estimation of carbon stock sequestrated through rubber ( Hevea brasiliensis ) plantation in North Eastern regional of India. Indian Forester 2005,131(11):1429–1435.Google Scholar
- Lal R: Soil carbon sequestration to mitigate climate change. Geoderma 2004, 123: 1–22. 10.1016/j.geoderma.2004.01.032View ArticleGoogle Scholar
- Buringh P: Organic carbon in soils of world. In The Role of Terrestrial vegetation in global carbon cycle: Measurement by remote sensing. Edited by: Woodwell GM. John Wiley; 1984:91–109.Google Scholar
- Six J, Jastrow JD: Organic matter turnover. Encycl Soil Sci 2002, 936–942.Google Scholar
- Baker DF: Reassessing carbon sinks. Science 2007, 316: 1708–1709. 10.1126/science.1144863View ArticleGoogle Scholar
- Jobbagy EG, Jackson RB: The vertical distribution of soil organic and its relation to climate and vegetation. Ecology Application 2000, 10: 423–426. 10.1890/1051-0761(2000)010[0423:TVDOSO]2.0.CO;2View ArticleGoogle Scholar
- Sevgi O, Tecimen HB: Changes in Austrian Pine forest floor properties in relation with altitude in mountainous areas. Journal of Forest Science 2008, 54: 306–313.Google Scholar
- Eswaran H, Reich PF, Kimble JM, Beinroth FH, Padmanabhan E, Moncharoen P: Global Climate Change and Pedogenic Carbonates. Edited by: Lal R, et al. Lewis Publishers, Fl, USA; 1999:15–25.Google Scholar
- Bhattacharyya T, Pal DK, Chandran P, Ray SK, Mandal C, Telpande B: Soil carbon storage capacity as a tool to prioritize areas for carbon sequestration. Current Science 2008, 95: 482–494.Google Scholar
- Meentemeyer V, Berg B: Regional variation in rate of mass loss of Pinus sylvestris needle litter in Swedish pine forest as influenced by climate and litter quality. Scand J For Res 1986, 1: 167–180. 10.1080/02827588609382409View ArticleGoogle Scholar
- Lal R: Soil carbon sequestration impacts on global change and food security. Science 2004, 304: 1623–1627. 10.1126/science.1097396View ArticleGoogle Scholar
- Post WM, Izaurralde RC, Mann LK, Bliss N: Monitoring and verifying changes of organic carbon in soil. Climate Change 2001, 51: 73–99. 10.1023/A:1017514802028View ArticleGoogle Scholar
- Baes CF Jr, Goeller HE, Olson JS, Rotty RM: Carbon dioxide and climate: the uncontrolled experiment. Am Sci 1977, 65: 310–320.Google Scholar
- Bolin B: The carbon cycle. Sci Am 1970, 233: 124–132.View ArticleGoogle Scholar
- Jenny H, Raychaudhuri SP: Effect of Climate and Cultivation on Nitrogen and Organic Matter Reserves in Indian Soils. ICAR, New Delhi, India 1960, 126.Google Scholar
- Gupta RK, Rao DL: Potential of wastelands for sequestering carbon by reforestation. Current Science 1994, 66: 378–380.Google Scholar
- Eswaran H, Van DB, Reich P: Organic carbon in soils of the world. Soil Sci Soc Am J 1993, 57: 192–194.View ArticleGoogle Scholar
- Velayutham M, Pal DK, Bhattacharyya T: Global Climate Change and Tropical Ecosystems. Edited by: Lal R, Kimble JM, Stewart BA. Lewis Publishers, Boca Raton, FL; 2000:71–96.Google Scholar
- Buringh P: The Role of Terrestrial Vegetation in the Global Carbon Cycle Measurements by Remote Sensing. Edited by: Woodwell GM. John Wiley, New York; 1984:91–109.Google Scholar
- Kimble J, Cook T, Eswaran H: Proc Symp Characterization and Role of Organic Matter in Different Soils, 14th Soil Sci, Kyoto, Japan, 12–18 August, Wageningen, . the Netherlands 1990, 250–258.Google Scholar
- Grace P, Post W, Hennessy K: The potential impact of climate change on Australia's soil organic carbon resources. Carbon Balance and Management 2006, 1: 14. 10.1186/1750-0680-1-14View ArticleGoogle Scholar
- Dinakaran J, Krishnayya NSR: Variation in type of vegetal cover and heterogeneity of soil organic carbon in affecting sink capacity of tropical soils. Current Science 2008, 94: 9.Google Scholar
- Alamgir M, Amin MA: Storage of organic carbon in forest undergrowth, litter and soil within geoposition of Chittagong (south) forest division, Bangladesh. International Journal of Usufruct Management 2008,9(1):75–91.Google Scholar
- Wang S, Huang M, Shao X, Mickler AR, LI K, Ji J: Vertical distribution of soil organic carbon in China. Environ Manage 2004, 33: 200–209. 10.1007/s00267-003-9130-5View ArticleGoogle Scholar
- Markus E, Ladina A, Aldo M, Salvatore R, Markus N, Rene V: Effect of climate and vegetation on soil organic carbon, humus fractions, allophones, imogolite, kaolinite and oxyhydroxides in volcanic soils of etna (Sicily). Soil Science 2007, 172: 673–691. 10.1097/ss.0b013e31809eda23View ArticleGoogle Scholar
- Havelin JL, Kissel DE, Maddux LD, Classe MM, Long JH: Crop rotation and tillage effects on soil carbon and nitrogen. Soil Sci Soc Am J 2003, 54: 448–452.View ArticleGoogle Scholar
- Lal R: Conservation tillage for sustainable agriculture: tropics vs. temperate environment. Advances in Agronomy 1989, 42: 186–197.Google Scholar
- Blevines RL, Frye WW: Conservation tillage: An ecological approach in soil management. Advances in Agronomy 1993, 51: 33–78. full_textView ArticleGoogle Scholar
- Singh G: Carbon sequestration under an Agri-silvicultural system in the Arid region. Indian Forester 2005, 147: 543–552.Google Scholar
- Woodall C, Liknes G: Climatic regions as an indicator of forest coarse and fine woody debris carbon stocks in the United States. Carbon Balance and Management 2008, 3: 5. 10.1186/1750-0680-3-5View ArticleGoogle Scholar
- Jha MN, Gupta MK, Raina AK: Carbon sequestration: Forest Soil and Land Use Management. Annals of Forestry 2001,9(2):249–256.Google Scholar
- Don Axel, Schumacher Jens, Scherer-Lorenzen Michael, Scholten Thomas, Schulze Ernst-Detlef: Spatial and vertical variation of soil carbon at two grassland sites-Implications for measuring soil carbon stocks. Geoderma 2007, 141: 272–282. 10.1016/j.geoderma.2007.06.003View ArticleGoogle Scholar
- Jobbagy EG, Jackson RB: The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecological Applications 2000,10(2):423–436. 10.1890/1051-0761(2000)010[0423:TVDOSO]2.0.CO;2View ArticleGoogle Scholar
- Conant RT, Paustian K: Potential soil carbon sequestration in overgrazed grassland ecosystems. Global Biogeochemical Cycles 2002,16(4):1143. 10.1029/2001GB001661View ArticleGoogle Scholar
- Schlesinger WH: An Analysis of Global Change. Academic Press, San Diego; 1997.Google Scholar
- Jenny H: The Soil Resource: Origin and Behavior, Ecological Studies. Volume 37. Springer-Verlag, New York; 1980.View ArticleGoogle Scholar
- Percival HJ, Parfitt RL, Scott NA: Factors controlling soil carbon levels in New Zealand grasslands: is clay content important. Soil Science Society of America Journal 2000, 64: 1623–1630.View ArticleGoogle Scholar
- Lemenih M, Itanna F: Soil carbon stocks and turnovers in various vegetation type and arable lands along an elevation gradient in southern Ethiopia. Geoderma 2004, 123: 177–188. 10.1016/j.geoderma.2004.02.004View ArticleGoogle Scholar
- Alvarez R, Lavado RS: Climate, organic matter and clay content relationships in the Pampa and Chaco soils, Argentina. Geoderma 1998, 83: 127–141. 10.1016/S0016-7061(97)00141-9View ArticleGoogle Scholar
- Sah SP, Brumme R: Altitudinal gradients of natural abundance of stable isotopes of nitrogen and carbon in the needles and soil of a pine forest in Nepal. Journal of Forest science 2003,49(1):19–26.Google Scholar
- Gairola S, Rawal RS, Todaria NP: Forest vegetation patterns along an altitudinal gradient in Sub-alpine zone of West Himalaya India. African Journal of Plant Science 2(6):42–48.
- Korner C: A re-assessment of high elevation of tree line positions and their explanations. Oecologia 1998, 115: 445–459. 10.1007/s004420050540View ArticleGoogle Scholar
- Hardy FG, Syaukani , Eggleton P: The effect of altitude and rainfall on the composition of termites (Isotera) of the Leuser ecosysrem (Sumatra, Indonesia). Journal of Tropical Ecology 2001, 17: 379–393.Google Scholar
- Garten CT, Post WM, Hanson PJ, Cooper LW: Forest soil carbon inventories and dynamics along an elevation gradient in the southern Appalachian Mountains. Biogeochemistry 1999, 45: 115–145. 10.1007/BF01106778Google Scholar
- Quideau SA, Chadwick QA, Benesi A, Graham RC, Anderson MA: A direct link between forest vegetation type and soil organic matter composition. Geoderma 2001, 104: 41–60. 10.1016/S0016-7061(01)00055-6View ArticleGoogle Scholar
- Tan ZX, Lal R, Smeck NE, Calhoun FG: Relationships between surface soil organic carbon pool and site variables. Geoderma 2004, 21: 185–187.Google Scholar
- Sims ZR, Nielsen GA: Organic carbon in Montana soils as related to clay content and climate. Soil Science Society of America Journal 1986, 50: 1269–1271.View ArticleGoogle Scholar
- Tate KR: Assessment, based on a climosequence of soil in tussock grasslands, of soil carbon storage and release in response to global warming. Journal of Soil Science 1992, 43: 697–707. 10.1111/j.1365-2389.1992.tb00169.xView ArticleGoogle Scholar
- Shalu Adhikari1, Roshan M, Bajracharaya1 , Bishal KS: A Review of Carbon Dynamics and Sequestration. Wetlands Journal of Wetlands Ecology 2009, 2: 41–45.Google Scholar
- Krishnan P, Bourgeon G, Seen DL, Nair KM, Prasanna R, Srinivas S, Muthusankar G, Dufy L, Ramesh BR: Organic carbon stock map for soils of Southern India. A multifactor approach. Current Science 2007, 5: 10.Google Scholar
- Hairiah K, Sitompul VS, Noordwijk M, Palm C: Methodology for sampling carbon stocks above and below ground. ASB Lecture Notes 4B. International Centre for Research in Agro forestry, Indonesia, Published in Dec., 2001 [http://www.icraf.cgiar.org/sea]Google Scholar
- Walky A, Black IA: An examination of the Degtiareff method for deteming soil organic matter and proposed modification of the chromic acid titration method. Soil Science 1934, 63: 29–38.View ArticleGoogle Scholar
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