Abstract

As the biggest "carbon sinks" and "carbon source" of terrestrial ecosystems, soil organic carbon plays a crucial role in global warming and agricultural production. Both of natural and human factors has a momentous influence on soil organic carbon. The cultivated soil of mountainous and hilly area located in Yunyang County was selected as the object area of research. Elevation, slope, parent materials, slope position and Topography Wetness (TWI) are considered as essential factors for soil organic carbon. In addition, category variables were introduced into the regression model through path analysis, the mechanism of factors on cultivated Soil Organic Carbon (SOC) density was discussed. The variability of SOC density was gained by border analysis and anisotropic analysis. The results show that the average, 0-20 cm, cultivated SOC density is 2.91 kg/m2 and the cultivated soil carbon storage is 1838.75×106 kg in the study area. The correlation between elevation and SOC density is significant (0.329**). Topography wetness index (TWI) also has great correlation with SOC density (0.256**). Areas covered by Gray- brown purple mud (shale) efflorescence and Purple sand and mud (shale) efflorescence have lower SOC density. The sequence of SOCD in different slope position is: Valley>slope foot>ridge>slope shoulder>slope back. From spatial variation aspect, anisotropic analysis illuminates that, spatial variability of SOC density is more drastic in south-north orientation than in east-west orientation.

Keywords:

Anisotropic, impact factors, soil organic carbon,

References

1. Batjes, N.H., 1996. Total carbon and nitrogen in the soils of the world. Eur. J. Soil Sci., 47: 151-163.
   CrossRef    Direct Link
2. Chen, X.F. and Y. Xie, 2009. Spatial distribution of soil organic carbon density in Anhui province based on GIS. Sci. Geograph. Sinica, 29: 541-544.
   
3. Chuai, X.W., X.J. Huang, W.J. Wang, M. Zhang, L. Lai and Q.L. Liao, 2012. Spatial variability of soil organic carbon and related factors in Jiangsu province China. Pedosphere, 22(3): 404-414.
   CrossRef    Direct Link
4. Claessens, L., P.H. Verburg, J.M. Schoorl and A. Veldkamp, 2006. Contribution of topographically based landslide hazard modelling to the analysis of the spatial distribution and ecology of kauri (Agathis australis). Landscape Ecol., 21(1): 63-76.
   CrossRef    Direct Link
5. Cresser, M.S., R.L. Gonzalez and A. Leon, 2007. Evaluation of the use of soil depth and parent material data when predicting soil organic carbon concentration from LOI values. Geoderma, 140: 132-139.
   CrossRef    Direct Link
6. Dai, W.H. and Y. Huang, 2006. Relation of soil organic matter concentration to climate and altitude in zonal soils of China. Catena, 65: 87-94.
   CrossRef    Direct Link
7. Don, A., J. Schumacher, M. Scherer-Lorenzen, T. Scholten and E.D. Schulze, 2007. Spatial and vertical variation of soil carbon at two grassland sites-implications for measuring soil carbon stocks. Geoderma, 141: 272-282.
   CrossRef    Direct Link
8. Du, J.J. and Z.W. Chen, 2012. Using linear regression in SPSS to achieve path analysis. Biol. Bull., 45: 4-7.
   
9. FAO, 1976. A Framework for Land Evaluation. Soil Bulletins No. 32, FAO, Rome.
   
10. Greenland, D.J. and I. Szabolcs, 1994. Soil Resilience and Sustainable Land Use. CAB International, Wallingford, pp: 561, ISBN: 0851988717.
    
11. Grüneberg, E., I. Schöning, E.K.V. Kalko and W.W. Weisser, 2010. Regional organic carbon stock variability: A comparison between depth increments and soil horizons. Geoderma, 155: 426-433.
    CrossRef    Direct Link
12. Guo, S.L., S.G. Che, W. Liang and Q.K. Yang, 2010. SOC spatial distribution at small Wangdonggou watershed in gully region of the Loess Plateau. Acta Ecol. Sinica, 30: 52-59.
    Direct Link
13. Li, Y.N., G.Y. Wang and W. Li, 2002. Soil respiration and carbon cycle. Earth. Sci. Front., 9: 351-357.
    
14. Longbottom, T.L., A.T. Small, L.A. Owen and M.K. Murari, 2014. Climatic and topographic controls on soil organic matter storage and dynamics in the Indian Himalaya: Potential carbon cycle-climate change feedbacks. CATENA, 119: 125-135.
    CrossRef    Direct Link
15. Lu, X.Y., H.J. Zhang, J.H. Chen, X.J. Ma and J.Y. Zhang, 2013. Relationship of topographic factors and soil organic carbon density under plantation: A case in loess hilly region in western Shanxi province, China. Northeast Forestry Univ., 41: 48-58.
    
16. Martin, D., T. Lal, C.B. Sachdev and J.P. Sharma, 2010. Soil organic carbon storage changes with climate change, landform and land use conditions in Garhwal hills of the Indian Himalayan mountains. Agr. Ecosyst. Environ., 138: 64-73.
    
17. Milne, G., 1934. Some suggested units of classification and mapping, particularly for East African soils. Soil Res., 4: 183-198.
    
18. Miao, Q., et al., 2010. Scale effect of climatic factors on soil organic carbon. Acta Pedol. Sinica, 47: 170-178.
    
19. Mou, P., R.H. Jones, D.L. Guo and A. Lister, 2005. Regeneration strategies, disturbance and plant interactions as organizers of vegetation spatial patterns in a pine forest. Landscape Ecol., 20: 971-987.
    CrossRef    Direct Link
20. Nelson, D.M. and L.E. Sommer, 1975. A rapid and accurate method for estimating organic carbon in soil. Proc. Indiana. Acad. Sci., 84(1): 456-462.
    
21. Powers, J.S. and W.H. Schlesinger, 2002. Relationships among soil carbon distributions and biophysical factors at nested spatial scales in rain forests of northeastern Costa Rica. Geoderma, 109: 165-190.
    CrossRef    Direct Link
22. Qin, C.Z., A.X. Zhou, X. Shi, B.L. Li, T. Pei and C.H. Zhou, 2007. Fuzzy inference of spatial gradation of slope positions. Geogr. Res., 26: 1165-1175.
    Direct Link
23. Qin, C.Z., Y.J. Lu, L.L. Bao, A.X. Zhu, W.L. Qu and W.M. Chen, 2009. Simple digital terrain analysis software (SimDTA1.0) and its application in fuzzy classification of slope positions. Geo-Inform. Sci., 11: 737-743.
    
24. Singh, S.K., A.K. Singh, B.K. Sharma and J.C. Tarafdar, 2007. Carbon stock and organic carbon dynamics in soils of Rajasthan, India. J. Arid. Environ., 68: 408-421.
    CrossRef    Direct Link
25. Soil Survey Staff, 1993. Soil Survey Manual. Agricultural Handbook No. 18. US Department of Agriculture, Washington, D.C., USA.
    
26. Somaratne, S., G. Seneviratne and U. Coomaraswamy, 2005. Prediction of soil organic carbon across different land-use patterns: A neural network approach. Soil. Sci. Soc. Am. J., 69: 1580-1904.
    CrossRef    Direct Link
27. Tan, Z.X., R. Lala, N.E. Smecka, F.G. Calhouna, B.K. Slater et al., 2004a. Taxonomic and geographic distribution of soil organic carbon pools in Ohio. Soil. Sci. Soc. Am. J., 68: 1896-1904.
    CrossRef    Direct Link
28. Tan, Z.X., R. Lal, N.E. Smeck and F.G. Calhoun, 2004b. Relationships between surface soil organic carbon pool and site variables. Geoderma, 121: 187-195.
    CrossRef    Direct Link
29. Vallejo, A.M., L. Claessens, J. Stoorvogel and G.B.M. Heuvelink, 2008. Small scale digital soil mapping in Southeastern Kenya. CATENA, 76: 44-53.
    CrossRef    Direct Link
30. Wang, S.F., X. Wang and Z. Ouyang, 2012. Effects of land use, climate, topography and soil properties on regional soil organic carbon and total nitrogen in the Upstream Watershed of Miyun reservoir, North China. J. Environ. Sci., 24: 387-395.
    CrossRef    
31. Wang, S.Q., C.H. Zhou, K.R. Li, S.L. Zhu and F.H. Huang, 2000. Analysis on spatial distribution characteristics soil organic carbon reservoir in China. J. Geogr. Sci., 55: 533-544.
    Direct Link
32. Wilson, J.P. and J.C. Gallant, 2000. Terrain Analysis: Principles and Applications. John Wiley and Sons, New York, USA.
    
33. Xie, X.L., B. Sun, H.Z. Zhou, Z.P. Li and A.B. Li, 2004. Organic carbon density and storage in soil of china and spatial analysis. Acta Pedol. Sinica, 41: 35-43.
    
34. Xu, X., Y. Zhou, H.H. Ruan, Y.Q. Luo and J.S. Wang, 2010. Temperature sensitivity increases with soil organic carbon recalcitrance along an elevational gradient in the Wuyi Mountains, China. Soil Biol. Biochem., 42: 1811-1815.
    CrossRef    Direct Link
35. Yu, D., X. Shi, W. Sun, H. Wang, Q. Liu and Y. Zhao, 2005. Estimation of China soil organic carbon storage and density based on 1:1000000 soil database. Chinese J. Appl. Ecol., 16: 2279-2283.
    
36. Zhang, C.X., Q.K. Yang and R. Li, 2005. Advancement in topographic wetness index and its application. Progress. Geograph., 24: 116-223.
    

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