Soil organic matter is stored and stabilized by sticking to clay particles and forming aggregates. A study looked at two types of soil to see which process is more important. They found that in one soil, more organic carbon is trapped in aggregates than stuck to clay, showing that aggregates are key for storing carbon. In the other soil, more carbon is stuck to clay, especially deeper down. This means that different soils store carbon in different ways, with one relying more on aggregates and the other on clay.