Coexistence of tree species promotes the similarity of elementome in soil profiles

Purpose: The soil elementome has been recently proposed as a promising novel approach for describing the response of soil bioelemental composition to tree species. Using bioelement stoichiometry, we explored the effects of soil biogeochemical processes and tree species coexistence on soil elementome. Methods: : Soil bioelements were analyzed at three soil layers (A, B and C horizons) in four forests ( Picea asperata (PA), Larix principis-rupprechtii (LP), Betula Platyphylla (BP), and Betula Platyphylla - Larix principis-rupprechtii (L-B) mixed forest) in Chongli District, Zhangjiakou City, Hebei Province, China., The soil elementomes of 11 bioelements (C, N, P, O, S, K, Ca, Na, Mg, Mn and Cr) were analyzed by principal component analysis (PCA) based on soil C:N:P stoichiometry. We calculated elementome distance (ED) to examine differences between soil horizons and forests. Results: : We found that soil elementomes in the soil layers decreased with depth and that ED between the B and C horizons was larger than that between A and B horizons. Moreover, differences in soil elementomes were smaller for tree species that often coexist compared to those that rarely live together. Conclusions: : Our results suggest that tree species coexistence promotes similarity in soil elementomes probably due to creation of similar soil conditions. The findings of this research provide a new understanding about the relationship between tree species coexistence and soil bioelemental composition or stoichiometry.