Response of soil bacteria community to experiment warming in three agroecosystems of the Tibet

Abstract

Studies on the response of soil bacterial communities to climate warming in croplands on the Qinghai-Tibet Plateau are currently insufficient. In April 2016, a field experiment incorporating two factors (warming and crop types) was initiated in the Tibet. The three crops were Medicago sativa, Elymus nutans and Hordeum vulgare. The 16 S technique was used to measure soil bacteria community at both 0–10 and 10–20 cm in August 2017. The functional α-diversity in the leguminous system exhibited higher sensitivities to warming. However, the taxonomic and phylogenetic α-diversity, as well as the key vertex numbers of species co-occurrence network in the gramineous system were more sensitive to warming. Furthermore, warming decreased the number of key vertices belonging to connectors in the Elymus nutans system, but increased the number of key vertices belonging to connectors in the Hordeum vulgare system at 10–20 cm. Notably, the α-diversity differences among the three systems under control conditions were not the same as those under warming conditions, and in some cases, they showed opposite trends. Warming homogenized the differences of total abundance and community assembly processes. Consequently, crop types, including distinctions between legumes and gramineae or annual and perennial varieties, were found to modulate the impact of warming on soil bacterial communities. The differences in soil bacterial communities among different agroecosystems in alpine regions could be reshaped by climate warming.

Keywords

• Biodiversity
• Co-occurrence network
• Community assembly
• α-diversity
• β-diversity
• Temperature sensitivity