Abstract: By using modified Tullgren method, the community composition of mesomicro arthropods in agricultural soils under longterm fertilization in HuangHuaiHai Plain was investigated in September 2008 and February 2009. There were seven fertilization treatments, i.e., chemical N, P and K (NPK), N and P (NP), N and K (NK), P and K (PK), organic manure (OM), OM and NPK (organic nitrogen∶fertilizer nitrogen = 1∶1) (OMNPK), and no-fertilization (CK). Treatments OM and OMNPK increased the abundance and diversity of arthropods, while treatment NK had significant negative effects on soil arthropods because of the P deficiency. As for the dominant groups Collembola and Acari, treatments OM and OMNPK benefited the growth of Isotomidae, Hypogastruridae, and Onychiuridae (Collembola), while treatment NPK benefited Sminthuridae (Collembola). Treatment OMNPK had significant positive effects on Mesostigmata (Acari), and had definite positive effects on Oribatida and Prostigmata (Acari). Nitrogen fertilizer had no positive effects on Collembola, but increased the number of Acari.

Key words: Laris gmelinii plantation, Fertilization, Enzyme activity, Microbial amount