Ecological stoichiometry in leaves, roots, litters and soil among different plant communities in a desertified region of Northern China

Ecological stoichiometry reflects the element content and energy flow, which are important for biogeochemical cycling in ecosystems. However, the ecological stoichiometry in leaves, roots, litter and soil is largely unknown, especially in the desertified region of Northern China. Here, six dominant plant communities (Stipa bungeana, Agropyron mongolicum, Glycyrrhiza uralensis, Cynanchum komarovii, Artemisia ordosica, and Sophora alopecuroides) were collected, and the carbon (C), nitrogen (N) and phosphorus (P) contents of leaves, roots, litters and soil were measured to explore the C:N:P stoichiometry and its driving factors. The C:N:P stoichiometry in leaves, roots, litters, and soil varied widely, and the plant community had a significant effect on the C:N:P stoichiometry in this region. There were high soil C:N, C:P and N:P ratios in non-leguminous plant communities and a high leaf N:P ratio in leguminous plant communities, and the C:N and C:P ratios in leaves were higher than in those in roots in all plant communities (p < 0.05). A correlation analysis showed that the C, N and P contents of leaves, roots, and litter were positively related to the soil C, N and P contents of the 0-5 cm layer, and the correlation coefficients gradually weakened with the soil depth. Additionally, the soil properties (except soil P) led to increased variance of the C:N:P stoichiometry in leaves, roots, and litter, and there were strong links among the C:N:P stoichiometry in leaves, roots, litter and soil, suggesting that the variation in the C:N:P stoichiometry in leaves, roots, and litter was mainly controlled by the soil properties, which was especially true for soil microbial biomass carbon (SMBC) and nitrogen (SMBN) according to redundancy analysis (RDA). Overall, these results demonstrate that the patterns of the C:N:P stoichiometry and element distribution exhibit significant flexibility among these plant communities, providing basic data for improving the parameterization of future ecological models in the desertified region of Northern China.