ObjectiveForest litter plays an important role in the transmission of nutrients aboveground and underground in forest. Earthworm can influence the decomposition of litter by feeding, digestion, excretion, and burrowing, thereby affecting soil nutrient and soil microbial. This study was conducted to examine the effects of earthworm (Pheretima guillelmi) and litterfall (Pinus tabuliformis) addition on soil pH, soil organic carbon (SOC), soil total nitrogen(STN), microbial biomass carbon (SMBC) and microbial entropy (qMB).

MethodThrough indoor incubation experiments, four treatments were set as control(S), adding Pinus tabuliformis leaf litter (SP), inoculating earthworm (SE), inoculating earthworm and adding Pinus tabuliformis leaf litter(SPE). Soil samples were collected periodically on the 7 th day(D7), D14, D21, D28, D42, D56 after incubation.

ResultThe results showed that the pH values of treatments SE and SPE were higher than treatment S in all incubation period, but not reached a significant level (P>0.05); Regardless of adding leaf litter or not, the earthworm all had no significant influence on SOC and STN (P>0.05). At the end of the experiment, SE treatment decreased SMBC and qMB by 10.8% and 10.9%, respectively compared with control. In each sampling period, the SMBC and qMB of SP treatment were significantly higher than that of its corresponding treatment S(P < 0.05), and at the end of the experiment, they were significantly increased by 52.3% and 33.6% respectively by treatment SP. In each sampling period, the differences in SMBC and qMB between SPE treatment and SP treatment were significant. At the end of the experiment, compared with SP treatment, SPE treatment increased SMBC and qMB by 19.5% and 19.3%(P < 0.05), respectively.

ConclusionOur study has shown that, adding litter can increase the conversion efficiency of soil organic carbon to SMBC, and earthworm adding in litter can further promote this effect.