Abstract：In order to explore the changes of soil organic carbon and humus components in bare land
(BS), natural vegetation growth land (NG), straw returning bare land (BS+CS) and straw returning
corn land (CS), black soil under 12 years of long-term micro area experimental treatment in the black
soil area of Jilin Agricultural University was used as research object to study the effects of different
land use patterns on organic carbon and humus components of black soil. The results showed that the
order of soil organic carbon content was NG>CS>BS>BS+CS, and natural vegetation growth and
straw returning to corn land were beneficial to increasing soil organic carbon content. The content ofHE, HA, FA and HM in NG soil was higher, followed by HA in CS soil. The proportion of humus
components to organic carbon in different land use patterns was: fulvic acid carbon (FAC) < humic
acid carbon (HAC) < humin carbon (HMC). The degree of humification of CS soil was the largest in
the surface layer, and the degree of humification of BS in the subsurface soil was significantly accel‐
erated. NG was beneficial to the increase of HA proportion in soil organic carbon of the surface soil,
while NG was not conducive to increasing the relative content of FA in the surface soil. CS treatment
was higher than BS treatment. The relative content of FA in the subsurface soil of natural vegetation
growth areas (NG) decreased, while straw returning to corn land (CS) increased the relative content of
soil HM. In general, grassland and straw returning land are beneficial to the increase of carbon con‐
tent in soil organic carbon and humus components, accelerating the process of soil humification, but
not conducive to increasing the proportion of soil humus in soil organic carbon.
