Abstract: The 16 SrRNA gene high-throughput sequencing technology was used to analyze the effects of different tillage methods (A1 traditional tillage, A2 deep rotary tillage) and organic fertilizer levels (B1: 0kg·ha−1, B2: 7500 kg·ha−1, B3: 15000kg·ha−1, B4: 22500kg·ha−1) on the bacterial community structure of maize rhizosphere saline alkali soil, and predict their functions. The results showed that: (1) the interaction effect of deep rotary tillage and organic fertilizer application significantly increased the observed index, Chao1 index, ACE index and aromatic index(P<0.05). (2)The bacterial community in maize rhizosphere was mainly composed of 31 phyla and 497 genera, including Proteobacteria(37.4%−54.4%), Acidobacteria(8.6%−2.9%), Actinobacteria(5.2%−13.3%). The analysis of bacterial community showed that the bacterial community structure was similar among different tillage methods, and the abundance of bacteria was different among organic fertilizer application levels. (3)The correlation analysis showed that the soil pH value was significantly negatively correlated with ACE index, Observed index and Chao1 index(r=−0.56, P=0.004); The activity of invertase (IA) was positively correlated with ACE index, Observed index and Chao1 index(r=0.52, P=0.01). Redundancy analysis showed that alkali hydrolyzed nitrogen, available phosphorus, available potassium, organic matter, alkaline phosphatase, sucrase and pH value were the key environmental factors affecting the bacterial community structure of corn farmland soil. (4)Deep rotary tillage combined with organic fertilizer significantly increased the gene abundance of bacterial signal transduction function in the rhizosphere soil of maize fields, such as carbohydrate metabolism, amino acid metabolism, other amino acid metabolism, carbohydrate biosynthesis and metabolism, cofactor and vitamin metabolism. The functional gene abundance of soil bacteria was the highest under A2B3 treatment. In this study, the treatment of deep tillage and organic fertilizer application rate of 15000kg·ha−1 was the most beneficial ways to improve the bacterial diversity and function of corn farmland.

Key words: Deep rotary tillage, Organic fertilizer, Saline-alkali land, Bacterial community structure, Corn