Abstract: To clarify the composition and abundance of meiofauna, and dominant genera of freeliving marine nematodes, sediments were collected from Futian mangrove wetland in Shenzhen bay in the winter of 2018. The results showed that more than four meiofauna groups were recorded in the study area, including freeliving marine Nematode, Copepoda, Polychaeta, Oligochaeta and unidentified groups. Marine nematode was the most dominant group, accounting for 97.28% of the total abundance. The mean abundance of meiofauna was 490.73±465.09 ind·10 cm^-2. In total, 30 genera and 17 families of marine nematodes were identified from all the sampling sites. Dominant genera of marine nematode with dominance ≥5% were Paracanthonchus, Megadesmolaimus,Subsphaerolaimus, Terschellingia,Spinonema, Pseudochromadora and Pseudolella. Subsphaerolaimus major Nguyen & Gagarin, 2009, a new record of freeliving marine nematode species was measured and described. The main differences between the new record species and model species were compared.

Key words: nitrogen application rate., AquaCrop model, canopy cover degrees, grain yield, whole plastic-film mulching on double ridges