Pedosphere 21(2): 207--213, 2011
ISSN 1002-0160/CN 32-1315/P
©2011 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of soil sampling density on detected spatial variability of soil organic carbon in a red soil region of China |
YU Dong-Sheng1,2, ZHANG Zhong-Qi2,3,4, YANG Hao1 , SHI Xue-Zheng2,3, TAN Man-Zhi2, SUN Wei-Xia2 and WANG Hong-Jie2 |
1 College of Geographical Sciences, Nanjing Normal University, Nanjing 210046 (China)
2 State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
3 Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)
4 Xuzhou Normal University, Xuzhou 221116 (China) |
| ABSTRACT |
| Spatial variability of soil organic carbon (SOC) of different land use patterns and soil types was examined in a county-wide red soil region of South China,using six sampling densities,14,34,68,130,255,and 525 samples designed by the method of grid sampling in 6 different grid sizes,labeled as D14,D34,D68,D130,D255,and D525,respectively.The results showed that the coefficients of variation (CVs) of SOC decreased gradually from 62.8% to 47.4% with the increase in soil sampling densities.The SOC CVs in the paddy field change slightly from 30.8% to 28.7%,while those of the dry farmland and forest land decreased remarkably from 58.1% to 48.7% and from 99.3% to 64.4%,respectively.The SOC CVs of the paddy soil change slightly,while those of red soil decreased remarkably from 82.8% to 63.9%.About 604,500,and 353 (P < 0.05) samples would be needed a number of years later if the SOC change was supposedly 1.52 g kg-1,based on the CVs of SOC acquired from the present sampling densities of D14,D68,and D525,respectively.Moreover,based on the same SOC change and the present time CVs at D255,the ratio of samples needed for paddy field,dry farmland,and forest land should be 1:0.81:3.33,while the actual corresponding ratio in an equal interval grid sampling was 1:0.74:0.46.These indicated that the sampling density had important effect on the detection of SOC variability in the county-wide region,the equal interval grid sampling was not efficient enough,and the respective CV of each land use or soil type should be fully considered when determining the sampling number in the future. |
| Key Words: coefficient of variation, county-wide region, grid sampling, land use, soil type |
| Citation: Yu, D. S., Zhang, Z. Q., Yang, H., Shi, X. Z., Tan, M. Z., Sun, W. X. and Wang, H. J. 2011. Effect of soil sampling density on detected spatial variability of soil organic carbon in a red soil region of China. Pedosphere. 21(2): 207-213. |
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