Soil bacterial responses to experimental warming and drought across winter wheat growth stages in the North China Plain

Djifa Fidele Kpalari¹Yuanyuan Fu¹Sen Li^1*Hui Cao¹Rakhwe Kama²Abdoul Kader Mounkaila Hamani³Junming Liu⁴Shoutian Ma^1*东雪 吕⁵Yang Gao¹

• ¹Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
• ²South China Agricultural University College of Natural Resources and the Environment, Guangzhou, China
• ³Hainan University School of Tropical Agriculture and Forestry, Haikou, China
• ⁴Ludong University, Yantai, China
• ⁵Tarim University, Aral, China

While climate change alters the balance of the Earth's ecosystems, theits impact on the soil bacterial community remains poorly understood. A field experiment was conducted to assess the effects of warming, drought, and their combination on the soil bacterial community at different growth stages of winter wheat. Four treatments were defined for this study: warming at 1.5℃ combined with full irrigation (TWS) and deficit irrigation (TWD), then ambient temperature combined with full irrigation (TNS) and deficit irrigation (TND). The results indicated that TWS, unlike TND, promoted nitrogen availability for plants and root exudation. The abundance and diversity of the bacterial community were more responsive to different climatic stresses at the jointing stage than at other growth stages. Chloroflexi, Firmicutes, and Bacteroidota were positively correlated with soil inorganic nitrogenNH4+, NO3-, the root total organic carbon (TOC), and negatively correlated with available phosphorus (AP), available potassium (AK), soil organic carbonSOM, (SOC) under TND, while an opposite trend was observed with Actinobacteria and Proteobacteria. Furthermore, under TWS, Bacteroidota, unlike Actinobacteria, was positively correlated with NH4+, NO3-, TOC, and negatively correlated with AP, and SOC, and SOM. The bacterial community network feature values were higher under TWD and lower under TNS. These results indicate that the sensitivity of the rhizosphere bacterial community to the impacts of different climatic stresses varies according to the is not identical at all growth stages, and that the community is particularly more responsivesensitive at the jointing stage than at the laterother stages.