The study looked at how different factors like landforms, land use, and soil types affect the amount of organic carbon in soil in a gully watershed on the Loess Plateau. They found that the total organic carbon in soil didn't vary much, but labile organic carbon varied more. The highest levels of organic carbon were found in plateau land, forest and farm lands, and black loessial soils, while the lowest levels were in gully bottom, grass land, and rubified soils. The amount of labile organic carbon in soil changed quickly in response to environmental factors, while the amount of middle labile organic carbon changed more slowly.