Abstract:Spatial heterogeneous characteristics of aboveground biomass and total soil nitrogen and phosphorus in 0-20cm and 20-40cm depths of three different successional stage old-field communities, Artemisia scoparia(early stage), Stipa bungeana(mid stage) and Lespedeza dahurica(later stage), were analyzed using geostatistical methods. The correlations of aboveground biomass and total nitrogen and phosphorus at different scales were computed using partial Mantel analyses based on distance matrices. Moreover, the variations of aboveground biomass were partitioned into community space process and environment components (including soil nitrogen and phosphorus). The results show that: (1) total phosphorus of the three communities has relatively larger spatial autocorrelation coefficients than that of total nitrogen. Total nitrogen of different layers also has different spatial heterogeneous extent. The variability of total nitrogen in 0-20cm ranked as: L. dahurica>S. bungeana > A. scoparia, in 20-40cm: S. bungeana> L. dahurica >A. scoparia, so we infer that the variability of total nitrogen in the top layer increases as succession occurs, while in subsoil, the variability of mid-succession stage is greater than that of earlier and later succession stages. The total phosphorus in both layers also has greater variability in mid-succession stage and smaller values in earlier and later succession stages. (2) Aboveground biomass of the three communities has different spatial autocorrelation coefficients, S. bungeana has the smallest value. The variability were ranked as A. scoparia > L. dahurica >S. bungeana. The partial Mantel correlgram of A. scoparia community show significant positive partial correlation at the small scale (0.71m) between aboveground biomass and total nitrogen and relatively good negative correlation at the small scale (0.71m) with significant correlation between aboveground biomass and total phosphorus. For L. dahurica community, significant positive correlation between aboveground biomass and total phosphorus occurred at 7.07～20.51m scale, small scale (0.71m) also has great positive correlation. No significant correlation was found for S. bungeana community with either total nitrogen, or total phosphorus, (only at small scale, the value is relative great). (3) The environment, i.e., total nitrogen and phosphorus, explained about 19.59% of the spatial heterogeneity of L. dahurica aboveground biomass, 2.75% of A. scoparia，and 1.95% S. bungeana. The space process accounted for about 5.42% of the heterogeneity of A. scoparia, 1.79% of L. dahurica, and 1.16% of S. bungeana.