Soil organic matter (SOM), microbial
carbon (Cmic), and microbial nitrogen (Nmic) status
affected by the application of inorganic fertilizer and
organic amendments in subtropical paddy soils were
investigated. Soil samples were collected from the
plow layer of three long-term (17 years) field experiments
at Xinhua, Ningxiang, and Taojiang counties
in Hunan Province, China. Results showed that,
compared to the control, application of inorganic
fertilizer alone showed no significant effect on soil
organic C (SOC), total N (Ntot), Cmic and Nmic. The
application of inorganic fertilizer along with manure
or straw significantly increased SOC and Ntot and soil
Cmic and Nmic contents for all three sites, while
following an application of inorganic fertilizer along
with straw only for two sites. Cmic and Nmic were
closely correlated with SOC and Ntot, respectively. In
conclusion, application of inorganic fertilizer along
with manure or straw is an effective way of
enhancing SOM and microbial biomass in subtropical
paddy soils.