| Despite the crop residue is one of most important sources of organic matter and
nutrients to agriculture soils, there is little study on the effects of long-term warming
and tillage systems on residues decomposition. Soil was sampled from a 4-year field
warming experiment under till and no-till systems, and was incubated with 14C-labeled
maize residue at three temperatures (15, 21 and 27 ˚ C) for 59 days. Results showed
warming had a lasting effect on soil organic matter decomposition, as the warmed soil
produced significantly higher CO2 from both the till and no-till samples than
non-warmed soils. However, between warmed and non-warmed soils, more residues
were decomposed under no-till with higher 14CO2effluxes, while there was little
different to till. The values of microbial biomass carbon (MBC) and dissolved organic
carbon (DOC) showed warming-induced higher decline under till, while slight
decrease under no-till which indicated the less C availability under till than
no-till after long-term warming. Furthermore, warming induced higher specific
enzyme activities of three extracellular enzymes (β-glucosidase, chitinase and
sulfatase) before and after the incubation under no-till only. We conclude that
long-term warming leads to distinguish effects on the microbial physiology, which
could result in different residue decomposition depending on tillage systems. |