Soil macrofauna assemblage composition and functional groups in no-tillage with corn stover mulch agroecosystems in a mollisol area of northeastern China

Macrofauna is an important component of soil ecosystems, and strongly affects agricultural sustainability. In order to evaluate the effects of no-tillage with corn stover mulch on soil macrofauna assemblages in the mollisol agroecosystems, the abundance, diversity, composition, and the functional groups of the soil macrofauna were investigated in Lishu Conservation Tillage Research and Development Station located in northeastern China. The experimental design was a randomized complete block with four replicates for each treatment, and included no-tillage with four different amount of corn stover mulch (0, 2.5, 5 and 7.5 t/ha) and conventional tillage. Soil macrofauna samples were collected in April, July and October 2015. The results showed that the abundance and group richness of soil macrofauna were significantly higher in the no-tillage with corn stover mulch systems compared to conventional tillage. The composition of the fauna communities were different between treatments, especially between conventional tillage and no-tillage with 5 t/ha corn stover mulch, no-tillage with 7.5 t/ha corn stover mulch. The biological index V of the seven taxonomic groups showed that Oligochaeta, Coleoptera, Araneae and Hymenoptera were very highly suppressed by conventional tillage, while the magnitude of response of the other groups to tillage varied between the mulch treatments, as well as with the sampling time. The abundance of decomposers and predators was significantly enhanced by no-tillage with corn stover mulch (P < 0.05), but not significant for herbivores. The study results also showed that the amount of corn stover mulch had an influence on the abundance of soil macrofauna communities; however, a significant positive relationship between the amount of corn stover mulch and abundance of soil macrofauna was only observed in April. It is thus concluded that no-tillage with corn stover mulch seems to be beneficial to biological soil components where it favored the establishment of abundant and diverse soil macrofauna communities than conventional tillage in the mollisol area of northeastern China.