Response of soil faunal communities to tea tree cultivars in the hilly region of western Sichuan, China

Abstract

Soil fauna is vitally important to all soil ecosystems due to its significant role in humification and mineralization of plant residues, cycling of nutrients, improvement of soil porosity and structure, etc. Soil fauna is sensitive to land-use changes, fertilizer use, tillage, and land degradation. Tea production is one of the most important agricultural industries in China. However, very few studies have investigated the responses of soil fauna to tea tree (Camellia sinensis L.) cultivars; understanding these responses is crucial to maintaining soil health and biological diversity stability in such agricultural ecosystems. This paper concentrates on the impacts of tea trees on soil faunal community composition and diversity, forming the background of an evaluation of the land-use sustainability associated with various cultivars. Soil samples were collected at a depth of 0−20 cm from four major tea plantations in western Sichuan, China, with different cultivars (“Chuannong Huangyazao” - CH, “Fuding Dabai” - FD; “Chuanmu No.217” - CM, and “Chuancha No.3” - CC). The results showed that different tea tree cultivars in this study had significant (p < 0.05) influences on soil chemical properties. The soil at the FD plantation had the lowest pH, total nitrogen (TN), and available phosphorus (AP) but the highest available nitrogen (AN), while the soil at the CM plantation had the highest pH, AP and available potassium (AK). The highest soil faunal abundance (as indicated by the number of individuals per unit area) and community diversity (as indicated by Shannon and Margalef indices) occurred at the CC plantation. This result illustrated that compared to the other plantations, the CC plantation provided a more habitable environment and more nutrient resources for the soil faunal community development. The diversity of the soil faunal community was highly associated (p < 0.05) with variations in soil pH, organic carbon (OC), TN, AP and AK. The effects of tea tree cultivars on the rare soil faunal composition differed among the four tea plantations, but no significant difference in the composition of dominant and common taxa was observed. The relative abundance of the top ten soil faunal taxa was strongly associated with environmental variables. The two most important environmental factors (AP and AN) accounted for 57 % of the changes in soil faunal composition. This study highlighted cultivation and land-use management practices to promote soil health sustainability and soil faunal stability on land degraded by tea tree cultivars in western Sichuan, China.