The researchers analyzed soil samples in Beijing to study the variation of soil organic matter. They found that the distance of variation is about 70.80km, with the content of organic matter being moderately dependent on location. The variability is influenced by both structural and random factors. The strongest variation is seen in the north-south direction. The average organic matter content in the area is 15.21 g kg-1, below the standard level. High organic matter spots are in Mentougou District, while low spots are in Daxing, Shunyi, and Yangqing Districts. The precision of the map is lower at the edges due to sample site and density.