The construction level of artificial grassland is an important index of the development degree of grassland animal husbandry. Therefore, improving the productivity level of artificial grassland and promoting the sustainable utilization of artificial grassland have become important tasks that need to be urgently addressed. There have been numerous studies on the effects of monoculture on the soil microbial community structure in artificial grassland, but there is limited research on the effects of mixed sowing on the soil microbial community structure and the related patterns. In this study, Elymus nutans (En), Festuca sinensis (Fs), Avena sativa (As), and Poa pratensis (Pp) were used as common herbage materials in an alpine grassland pastoral area of the eastern Tibetan Plateau. Multi-density monoculture and mixed seeding were employed to establish artificial grassland communities with varying structures. By comparing the soil microbial community structure of the differently treated artificial planting grass, degraded grassland with bald spots, and natural grassland, it was confirmed that plant community diversity significantly influences the microbial community structure. The high-density planting treatment of multiple forage grasses had a more pronounced impact on the soil microbial community structure compared to that of the high-density planting treatment of a single variety of forage grass. The soil microbial community diversity index of the four mixed-planting treatments was higher than those of the other artificial grassland treatments and the natural grassland treatments, and the soil microbial community structure was most similar to that of the natural grassland. Avena sativa planting increased the abundance of Actinobacteria and Basidiomycota and decreased the number of Acidobacteria by increasing the soil pH value. The AFP (As+Fs+Pp) treatment reduced the proportion of Mortierellomycota in the soil by decreasing the content of available phosphorus. The AEFP (As+En+Fs+Pp) treatment increased the number of Proteobacteria by raising the soil total phosphorus content and reduced the abundance of Acidobacteria by lowering the soil pH value. Additionally, a machine learning method was used to evaluate the comprehensive performance of 21 artificial grassland treatments on nine soil physical and chemical properties. It was found that the AEFP mixed-planting and high-density planting treatments had the greatest improvement effect on the nine soil physical and chemical properties, which was conducive to sustainable land use.

The artificial planting of grassland serves as the most important means of grassland ecological restoration; however, the impact of artificial planting on soil microbial communities is not well understood. In this study, the evolution of the microbial community structure was studied using 16S and ITS gene sequencing techniques, and the microbial community differences between different forage grasses were analyzed, including different density cropping schemes, multi-year degraded grassland and natural grassland. It was found that the high-density planting scheme of multiple pastures exerts a great impact on soil nutrients as well as on the soil microbial community, effectively increasing the relative abundance of Actinobacteria and Basidiomycota, while the microbial community structure was found to be similar to that of natural grassland. However, in artificial planting treatment, the key node microflora group was noted to be bacteria, which was different from that in natural grassland, in which the key node microflora group was fungi. In comparison, fungi were found to be more sensitive than bacteria to different plantings.The rise in soil fungal diversity did not improve phosphate mineralization.Overall, this study may contribute to understanding the influence of artificial grassland on soil properties as well as the succession of microbial communities, How to accelerate the succession process of grassland ecosystem. which are of great significance in promoting artificial technology to restore the ecological environment.