Variation of composition and diversification of cropland soil fauna under different fertilizer application condition in the Black soil,Jilin province

Investigated soil fauna under different fertilizer application condition in the Black soil croplands in Aug,2003.Based on long-term fertilization experiment,the effects of 12 fertilization treatments,which was abandonment(Aband),no-fertilizer treatment(CK),application of N fertilizer(N),combined application of N and P(NP),combined application of N and K(NK),combined application of P and K(PK),combined application of N,P and K(NPK),combined application of organic material and NPK(organic nitrogen∶fertilizer nitrogen = 2∶1) (M1NPK),1.5 times of combined application of organic material and NPK(1.5MNPK), combined application of straw and NPK(SNPK),rotation of maize and soybean in 2∶1,the quantity of fertilizer was the same as treatment 8(Rot),and combined application of organic material and NPK(organic nitrogen∶fertilizer nitrogen = 1∶1)(M2NPK) on soil fauna was studied.108 soil samples and 17265 species(187 unidentitied) of cropland soil fauna individuals had been collected by handsorting and Modified Tullgren methods,belonging to 3 Phyla,9 Classes,3 Superorders,19 Orders and 48 families.The result showed that the guilds was mainly phytophage(35.53%) in the Black soil.The number of individual and the group of Macrofauna rank top in abandonment and N treatment,respectively,while mesofauna and microfauna rank top in the abandonment and the rotation,respectively,showing that the distribution of soil fauna was related to fertilizer application condition.The high-low sequence of Shannon-Weiner index of Macrofauna were: NP>N>1.5MNPK>PK>M2NPK>CK>NK>NPK>M1NPK>Rot>SNPK>Aband;While the high-low sequence Mesofauna and Microfauna were: M1NPK>M2NPK>SNPK>1.5MNPK>NP>CK>Rotation>NK>NPK>PK>N>Aband.The analysis of similarity coefficients of community showed that they were rather low,which indicated that the fauna compositions were heterogeneous.The similarities between SNPK,M1NPK and abandonment were much higher than the others,while the similarities between N and SNPK,M2NPK and rotation,CK and 1.5 MNPK and NPK was obvious lower than the others,indicating that different fertilizer applications treatments could affect internal environment of soil ecosystem,then proceed to the soil fauna community.