Effects of land use changes on soil organic carbon and soil microbial biomass carbon in low hills of North Yanshan Mountains

Abstract

To reveal the effects of land use changes on soil organic carbon pool, four types of land use (M-G; natural grassland) (artificial forests changed from natural grassland including 36-years-old Populus simonii) M-36; 22-years-old P. simonii M-22, and sloping cropland M-A) were selected in the low hills of north Yanshan Mountains to investigate the changes of soil organic carbon (SOC) and soil microbial biomass carbon (SMBC). The results show that SOCs and SMBCs were significantly affected by land use changes, and the effects were significantly different among the four types of land use (p<0.05): M36>M-22>M-G>M-A. Land use changes did not affect the vertical distribution of SOCs or SMBCs, which decreased with increase in soil depth. The four types of land use affected soil microbial biomass quotient (SMBC/SOC) in different ways. Analysis shows that the contents of SOC and SMBC increased after the transformation of M-G into man-made forests, but slightly decreased after the transformation into M-A, indicating that man-made forests were more capable than M-G in maintaining healthy and high-quality soils, but M-A was unfavourable for the development into higher soil quality.