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| Spatial variability and scale effect of soil bulk density of farm land in South China |
| XU Cuilan1, HOU Shunan1, YAO Zidong2, ZHANG Fei3, SHE Dongli3 |
| 1. Jiangsu Provincial Center for Land Consolidation and Rehabilitation, Nanjing, Jiangsu 210017, China; 2. College of Environment, Hohai University, Nanjing, Jiangsu 210098, China; 3. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, China |
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Abstract Taking a typical farm land in South China as the test field, the spatial variability and scale effect of bulk density of soils harvested at different soil depths(0-10, 10-20 cm)in the selected field were analysed by using classical statistical and geostatistical methods, and the spatial interpolation of soil bulk density in the field was estimated. The results indicated that the coefficient of variation(CV)of bulk density was small and the variation was weak. A semi-variogram analysis showed that the C0/(C0+C)values of the measured soil bulk density were lower than 10%, indicating the spatial heterogeneity resulted from the spatial variability of soil bulk density was significant. For the scale effect, the CV decreased firstly and then increased with increasing sampling interval. By adjusting the location of sampling points("re-sampling"), it was found that the CV of soil bulk density was small(6.32%-7.92%)and the correlation distance decreased when the sampling interval increased. It was suggested that the sampling interval affected CV a little after the interval was decreased to a certain value. The spatial distribution pattern of soil bulk density in two layers also showed a spatial correlation based on the density spatial interpolation and contours, i.e. a significant positive correlation with a correlation coefficient of 0.76. Furthermore, the spatial variability of soil bulk density was affected by human activities largely.
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Received: 11 October 2016
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