Corn cultivation alters bacterial diversity and function in salinized soils of the Diversionary Yellow River Irrigation Area

Soil salinity is one of the global environmental problems affecting agroecosystems and sustainable development of agriculture. Bacteria are involved in nutrient cycling processes such as soil carbon, nitrogen and phosphorus, and play a crucial role in soil ecosystem stability and soil fertility maintenance. In order to clarify the influence of plant restoration on the structure and diversity of bacterial communities in salinized soils, we took salinized soils in the Yellow River Irrigation Area of Ningxia as samples, and used high-throughput macro-genome microbial sequencing technology to carry out comparative studies on the diversity of bacteria in the maize rhizosphere soil (CR), maize non-rhizosphere soil (C), and wasteland (H), analyze the characteristics of bacterial diversity and changes in community structure and function among the selected three soils, and reveal the correlation between microorganisms and soil environmental factors. The changes of diversity, structure and function of bacteria communities in the selected three soil types were analyzed, and the correlation between diversity of bacteria communities and soil environmental factors were revealed. The results showed that bacteria detected in 12 soil samples from maize rhizosphere (CR), maize non-rhizosphere (C), and wasteland (H) belonged to 50 phylums, 67 classes, 153 orders, 350 families, 1111 genera and 4455 species. The soil bacteria richness and diversity in maize rhizosphere soil (CR) and maize non-rhizosphere soil (C) were more complex than that in the salinized wasteland, and ACE index, Chao1 index, Shannon index and Simpson index of the soil bacteria were in the following descending order: CR>C>H. At phylum level, compared with wasteland, the relative abundance of Proteobacteria and Actinobacteria in the maize rhizosphere soil (CR) and maize non-rhizosphere soil (C) increased by 4.53% and 3.33%, 3.97% and 5.73%, respectively. At genus level, compared with wasteland, the relative abundance of Nocardioides, Idiomarina, Arthrobacter and Pseud Arthrobacter in the maize rhizosphere soil (CR) and maize non-rhizosphere soil (C) increased. Comamonadaceae, Hyphomircobiales and Rhizobiaceae were the species with the greatest contribution of inter-group differences. Compared with wasteland (H), significant divergence in ecological niche was observed in the maize rhizosphere soil (CR) and maize non-rhizosphere soil (C). Maize planting could enhance the metabolic capacity of soil bacterial communities, and the relative abundance of maize rhizosphere soil (CR), and maize non-rhizosphere soil (C) bacteria involved in metabolic functions increased by 1.44% and 0.56%, respectively. Soil effective phosphorus (AP), total phosphorus (TP), effective nitrogen (AN), total salts (TS), and pH showed large impacts on the relative abundance in the level 3 functions. In conclusion, planting maize to repair salinized soil can change the structure and functional diversity of soil bacterial communities, which is of great significance in improving the microenvironment of salinized soil and promoting the microbial function of salinized soil and the sustainable use of land.