Zhao Ming-song Zhang Gan-lin Li De-cheng Zhao Yu-guo Wang De-cai. Spatial Variability of Soil Organic Matter and Factor Analysis in the South of Middle Jiangsu Plain. SCIENTIA GEOGRAPHICA SINICA 2012.

Abstract

In this research a square area (32°20′17″-32°44′50″N119°53′37″-120°14′4″E) about 1 350 km² was chosen as a case in the south of the middle Jiangsu plain. A total of 178 soil samples were collected according to nested scenario’s for the analysis of SOM content and soil mechanical composition. And furthermore spatial variability of SOM in the surface layer was analyzed using the Geostatistical and GIS method and its dominating factors too by means of correlation analysis and analysis of variance. The result suggested that the SOM content varied in the range of 28.51±7.80 g-kg with a coefficient of variation being 27.31% a moderate level. Geostatistical analysis suggests that the study area was very strong in spatial autocorrelation and the semi-variogram was best fitted by spherical model which was significant in anisotropy and the anisotropy ratio was 1.30. The variation at 39° and 219° in direction was the most severe and the spatial heterogeneity range at the direction was 33.26 km. The variation at 129° and 309° in direction was the slightest and the spatial heterogeneity range at the direction was 43.08 km. The structural factors played a dominating role in spatial variability of SOM. SOM in the area was distributed in a band of which high content was in the northeast in which the area of more than 30 g-kg accounting for 42% of the total area. But low content was in the southwest part. Correlation coefficients between SOM and soil mechanical composition were -0.548 for sand 0.534 for silt and 0.259 for clay respectively indicating the degree of correlation between SOM and sand was the strongest followed by silt and clay. Analysis of variance showed that parent material and soil type effected spatial variability of SOM significantly. Soil generated in the lake sediment had higher SOM content than that in the alluvial deposit. Soil type with high in clay and silt content had higher SOM content than that with sand content. Soil mechanical composition played a key role in spatial variability of the study area.