Responses of Bacterial Communities in Soils under Winter Wheat to Nightly Warming and Nitrogen Addition

Abstract

Understanding soil bacterial diversity under global warming is necessary because of its crucial role in soil nitrogen cycling. However, the interaction effect of warmer temperatures and nitrogen application on bacterial communities in the soils of winter wheat fields is unclear. In this study, the air temperature was increased with infrared heating, and this heating treatment was combined with nitrogen fertilizer application. The two-year continuous temperature increase significantly decreased the soil’s pH and nitrate nitrogen content, but significantly increased the content of soil available nutrients. Warming changed the community structure of the soil bacteria, and significantly increased the bacterial richness and diversity by 17.77% and 3.52%, respectively. The changes in the physical and chemical properties of the soil caused by the increased nighttime temperature decreased the percentage abundance of Pseudomonadota, which is the largest bacterial phylum, and plays an important role in the global carbon, sulfur, and nitrogen cycles. The structural equation model demonstrated that the influence of soil temperature on bacterial diversity was mediated through soil moisture. Nitrogen application rate directly affected soil bacterial diversity and was the most significant parameter influencing bacterial diversity.

Keywords

• global warming
• nitrogen
• soil bacteria
• soil physicochemical properties
• community diversity