Soil Nutrient Concentrations, Associations and Their Relationships with Canopy Tree Category and Size in the Southwestern China Tropical Rainforests

ABSTRACT

Soil nutrients and their stoichiometry are important indicators of nutrient biogeochemical cycles and various ecological processes. Soil nutrients are heterogeneously distributed and can be influenced by plants through litterfall and root activity. To explore the associations between soil nutrients and relationships between soil nutrients and plant characteristics, we selected three canopy tree categories based on abundance as dominant, common, and rare, with different plant sizes based on DBH (diameter at breast height, cm) for each species from three 1 ha tropical forest sites (Bu-Beng, P55, and Na-Ban-He forests), and collected the topsoil (0–10 cm) for physiochemical analysis. The results showed that soil nutrient concentrations were significantly different among the three forest sites. For soil total C, N, and P associations, soil total C and N had significant associations at all three sites; however, the associations of soil total C-P and N-P varied among sites. The plant category had significant relationships with soil stoichiometry, whereas plant size had significant relationships with soil nutrient concentrations; these relationships varied among the three sites. The results indicate that soil nutrient heterogeneity is influenced by tree category and size. Future studies should include a larger sample size to further validate these results.

KEYWORDS:

• Soil nutrients
• tree size
• canopy tree category
• plant soil feedback
• tropical rainforest

Acknowledgments

This study was supported by the National Natural Science Foundation of China under Grant [42071074; 42061144005]. We appreciate the Institutional Center for Shared Technologies and Facilities of Xishuangbanna Tropical Botanical Garden, CAS for nutrient analysis, and the Xishuangbanna Station for Tropical Rain Forest Ecosystem Studies (XSTRE) for providing plot altitude, tree species information and assistance in the field study. We thank Defu Chen for his assistance in the field and Zhiling Chen for her assistance in the lab work. We also thank anonymous reviewers for improving earlier versions of the manuscript. We would like to thank Editage (www.editage.cn) for English language editing.

Correspondence: Shangwen Xia ([email protected])

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [42061144005,42071074]; National Nature Science Foundation of China [42061144005,42071074].