The study looked at how soil organic carbon (SOC) is distributed in a region in northern China. They collected soil samples from different depths and analyzed the variation in SOC using statistical and geostatistical methods. The results showed that SOC levels decreased with depth, and were influenced by factors like soil texture, topography, and human activities. The distribution of SOC varied across the region, with higher levels in the northeast compared to the southwest in shallow soil layers. Overall, the estimated SOC storage for the area was around 25 Tg, with different interpolation methods giving slightly different results. The researchers found that the Inverse Distance Weighting (IDW) method was best for mapping SOC variability in the region.