土地利用变化对土壤团聚体微生物量碳的影响

Effects of Land Use on Soil Microbial Biomass Carbon in Aggregates

对福建省建瓯市山地红壤的天然林、人工林、次生林和园地等4种典型土地利用方式的不同土层（0-10cm,10-20 cm）土壤团聚体微生物量碳进行研究。结果表明：除茶园外,不同土地利用方式均表现出随着团聚体粒径增大,单位土壤微生物量碳增加的趋势。天然林转变为其他土地利用方式后,团聚体微生物量碳和单位土壤团聚体微生物量碳分别平均下降了18.66%~51.82%和21.20%~50.05%,但不同土地利用土壤团聚体微生物量碳的下降幅度小于土壤有机碳。土壤团聚体微生物商在本区域未表现出一定规律性。因此亚热带山地红壤内天然林转变为人工林、次生林和园地会导致土壤团聚体微生物量碳含量下降,但其能否作为表达土地利用变化敏感性指标,还需进一步斟酌。

In order to assess the impacts of land use change on soil microbial organic carbon（MBC） in aggregates, the contents of MBC of surface soil samples（0--10 cm, 10--20 cm）were investigated in Jian＇ou city, Fujian province, China. Results show that the contents of MBC in different size groups increased with increasing sizes of dry-sieved aggregates, except in Tea plantation. The contents of MBC in aggregates and bulk soil in 0--20 cm decreased respectively by 18.66%-51.82% and 21.20%-50.05% while natural forest conversed into other iand use practices. MBC quotient had minimal impact on different land use in this area. We conclude that the conversion of natural forest into other land use leads to a loss of MBC of soil aggregates, but it is not clear in this site if MBC was sensitive to land use change.