Abstract:1821 soil samples (GPS used for recording sample location) were collected in agricultural lands in Taiyuan in 2005. Total soil organic matter and nitrogen contents were measured. The spatial pattern of the data were analyzed using both traditional descriptive statistics and geo-statistics. The results indicated that soil organic matter and total nitrogen contents are at moderate level of soil fertility according to the soil fertility classification standards of the second national soil survey in 1980s.
The semivariograms of geostatistics analysis indicated the spatial autocorrelations for soil organic matter and soil total nitrogen, with spatial dependence of 122.4 km and 75.6 km, respectively. The spatial variability of soil total nitrogen content is mainly controlled by its auto-spatial dependence, whilst spatial autocorrelation and random both contribute to the spatial structure of soil organic matter. The distribution of soil total nitrogen and organic matter was controlled by soil types, elevation, land use and human factors such as the impact of production activities.
The spatial distributions of soil organic matter and soil total nitrogen content interpolated by ordinary kriging also demonstrate that in Taiyuan soil organic matter and soil total nitrogen have significantly different spatial structure due to the soil contamination by coal mining dusts in Loufan County and Gujiao County and other topographical and geomorphologic factors.
The study showed the spatial pattern soil organic matter and total N in Taiyuan due to complex natural and social variables and provides a scientific basis for the evaluation and sustainable management of soil fertility and nutrient resources.