Changes in Nutrient-Regulated Soil Microbial Communities in Soils Concomitant with Grassland Restoration in the Alpine Mining Region of the Qilian Mountains

Abstract

In response to the significant ecological damage caused by unsustainable mining practices in the Qilian Mountains, ecological restoration projects have been undertaken in recent years. Analyzing the changes in soil microbial communities during the restoration process of mine meadows helps to reveal the mechanism of the restoration process in alpine mining areas. To explore the characteristics of soil microbial community distribution and their relationships with soil environmental factors during the restoration of alpine grasslands in the Qilian Mountains, we conducted surveys and analyses in two restoration levels low restoration (LR) and high restoration (HR) in the eastern Qilian Mountains, along with an undisturbed natural grassland control (NG). We found that as the degree of high-altitude mining area recovery increases, there were significant increases in vegetation cover, vegetation height, above-ground biomass, vegetation Shannon–Wiener index, soil organic carbon (SOC), soil water content (SWC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available phosphorus (AP), and available nitrogen (AN). Conversely, soil pH and electrical conductivity (EC) significantly decreased, with soil pH decreasing from 6.93 to 4.13. Restoration of high-altitude mining area grasslands significantly alters the distribution and composition of soil bacteria and fungi, while the impact on soil microbial community changes was not significant. Notably, with increasing recovery level, the dominant bacterial phyla are Acidobacteria and Proteobacteria, while the dominant fungal phyla are Ascomycota and Basidiomycota. These results indicate that changes in vegetation and soil properties both affect the composition of soil microbial communities, with soil properties having a greater influence. Soil fertility and nutrient levels emerge as the primary drivers influencing soil microbial composition communities and the degree of high-altitude mining area grassland recovery.

Microbial Community Response to Alpine Meadow Degradation and Its Impact on Soil Nutrient Cycling

“…It has been suggested that both alpine meadow desertification and highland sage-grouse activity may increase the risk of infectious diseases, particularly fungal diseases, in alpine ecosystems [51]. This is consistent with the finding of a significant increase in plant pathogens during the degradation of alpine meadows in this study, suggesting that the degradation process is detrimental to the health of the meadow system [52]. An increase was found in the relative abundance of the plant pathogenic fungi Nectria, Aspergillus and Didymella.…”

Vegetation communities and soil properties along the restoration process of the Jinqianghe mine site in the Qilian Mountains, China

“…The life-form structure characteristics of plant communities at various restoration levels in alpine mining grassland are shown in Table 3 . The life-form classification follows the Whitaker growth type system, which is based on the degree of stem lignification in the community, as described by Yang et al. (2023a) .…”

“…Before restoration, due to the serious damage to the ecological environment caused by mining activities, a large amount of dumped soil and slag were piled up randomly, the soil was pressed and dug up, and the vegetation cover was extremely low, mainly through the natural restoration method of slag heap leveling, sowing grass seeds and fencing protection. With the expansion of the scale within the area of mining, the waste slag after mining destroyed the vegetation and degraded the vegetation on both sides of the river valley and the ditch, and the vegetation coverage on both sides of the river valley and the ditch before treatment was lower, the mine restoration from 2018 by the same restoration method of natural restoration ( Yang et al., 2023a ). The primary methods for natural restoration include the leveling of slag heaps, sowing of grass seeds, fence protection, and the facilitation of natural vegetation recovery.…”

Effects of Microbial Inoculants Combined with Chemical Fertilizer on Growth and Soil Nutrient Dynamics of Timothy (Phleum pratense L.)

“…The development of farmland ecosystems is closely related to dynamic changes in crop varieties, soil nutrients, and structure. Good crop quality and high yield can directly reflect high soil nutrient levels, with soil conditions serving as basic standards for evaluating crop growth [33]. In this experiment, the application of microbial inoculants with 85% chemical fertilizers not only promoted the growth of timothy but also improved the rhizosphere soil environment.…”