To target the lack of suitable grass species in the ecological restoration process of the Muli mining area, nine ecological grass species of Gramineae, Gentianaceae, Scrophulariaceae, and Ranunculaceae were selected as experimental materials to simulate the external alkaline environment for a seed germination test, which could be used to explore the response of seed germination to the environment. At the same time, Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, Koeleria cristata, and Elymus tangutorum were used as test materials to carry out a variety of comparison and screening tests of suitable seeding rates. The effects of the seeding rate on plant coverage, biomass, forage nutrients, and soil properties were analyzed by a variety of comparison and seeding rate tests. The results showed the following: (1) The relative germination rate of Koeleria cristata, Elymus tangutorum, Deschampsia cespitosa, and Poa pratensis L. ‘Qinghai’ was more than 70%, and the coverage in the returning green period was more than 60%, which was significantly higher than that of other treatments (p < 0.05) and can better adapt to the environment of the Muli mining area compared to other grass species. Meanwhile, the adaptability of Pedicularis kansuensis, Gentiana macrophylla, and Aconitum pendulum was weak. (2) It was found that when the seeding rate was 9 g·m⁻², the biomass of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos, and Koeleria cristata was the highest, which was 296.45 g·m⁻², 224.32 g·m⁻², and 236.35 g·m⁻², which was significantly higher than that of other treatments (p < 0.05); the aboveground biomass was 356.24 g·m⁻² when the seeding rate of Elymus tangutorum was 18 g·m⁻², which was significantly higher than that of other treatments (p < 0.05). The membership function showed that the comprehensive evaluation value was 0.701, 0.576, 0.610, and 0.673 when the seeding rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitos, and Koeleria cristata was 9 g·m⁻² and the seeding rate of Elymus tangutorum was 18 g·m⁻². To sum up, it is recommended that the four ecological grass species of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, Koeleria cristata, and Elymus tangutorum can be used as the main grass species for ecological restoration in high-altitude and alpine areas such as the Muli mining area, which is affected by an alpine climate and fragile habitats. The optimum sowing rate of Poa pratensis L. ‘Qinghai’, Deschampsia cespitosa, and Koeleria cristata is 9 g·m⁻², and that of Elymus tangutorum is 18 g·m⁻². This cultivation method can effectively promote plant growth and development, improve the physicochemical properties of soil, and is conducive to improving the stability and sustainability of artificial grassland in alpine mining areas.

The aim of this study was to establish a green fertilization regime combining microbial fertilizers and livestock manure organic fertilizer for two dominant oat cultivars (Avena sativa L. ‘Baiyan No.7’ and ‘Qingyin No.2’) in alpine ecosystems, providing technical support for sustainable forage production systems in grassland pastoral areas of the Qinghai-Tibet Plateau. The experiment was conducted following the principles of a randomized block design, with five application rates each of effective microbial fertilizer (EM) and compound microbial fertilizer (FH) applied in combination with 18,000 kg·hm⁻² of livestock manure organic fertilizer to systematically analyze their effects on oat agronomic traits, yield quality, and soil health. Key results demonstrated the following: for Avena sativa ‘Baiyan No.7’, effective microbial fertilizer (EM) application at 15.00 kg·hm⁻² significantly increased plant height by 41.29% (p < 0.05), while effective microbial fertilizer (EM) at 18.75 kg·hm⁻² optimized stomatal conductance and the transpiration rate by 73.29% and 46.42%, respectively. For Avena sativa L.‘Qingyin No.2’, compound microbial fertilizer (FH) application at 22.50 kg·hm⁻² enhanced plant height and relative chlorophyll content (SPAD value) of the flag leaf by 50.92% and 47.75%. Yield analysis revealed that compound microbial fertilizer (FH) application at 22.50 kg·hm⁻² increased the fresh forage yield and dry matter yield of ‘Baiyan No.7’ by 34.53% and 38.64%, respectively, with crude protein content reaching 11.02%. Maximum fresh forage yield (38,073.00 kg·hm⁻²) for ‘Qingyin No.2’ was achieved with effective microbial fertilizer (EM) at 11.25 kg·hm⁻², while compound microbial fertilizer (FH) at 22.50 kg·hm⁻² facilitated synergistic accumulation of crude protein (12.57%) and soluble sugars (15.58%). Soil organic carbon increased by 28.85% under compound microbial fertilizer (FH) at 22.50 kg·hm⁻² for ‘Baiyan No.7’, and by 26.21% under effective microbial fertilizer (EM) at 18.75 kg·hm⁻² for ‘Qingyin No.2’. In summary, a cultivar-specific green fertilization system was established: for Avena sativa L. ‘Baiyan No.7’: the application of 18.75 kg·hm⁻² effective microorganisms fertilizer with 18,000 kg·hm⁻² organic manure; for Avena sativa L. ‘Qingyin No.2’: the application of 22.50 kg·hm⁻² compound microbial fertilizer with 18,000 kg·hm⁻² organic manure. This system achieved triple sustainability objectives in alpine oat production: enhancing yield, optimizing quality, and improving soil health.

Hippophae rhamnoides subsp. sinensis Rousi has high ecological and medicinal value, and it is an important plant resource unique to the arid regions of Northwest China. Exploring the influence of climate characteristics and soil factors on the composition, diversity, and function of the rhizosphere bacterial community of Chinese seabuckthorn is of great value for developing and popularizing characteristic plant resources in the arid regions of Northwest China. In this study, the rhizosphere soil of 13 Chinese seabuckthorn distribution areas in the northwest of China was taken as the research object, the bacterial community map was constructed based on 16S rRNA gene high-throughput sequencing technology, and the species abundance composition, structural diversity, molecular co-occurrence network, and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt), as well as the function of rhizosphere soil bacterial community, were systematically studied. Combined with Mantel test and redundancy analysis (RDA), the key habitat factors driving the rhizosphere soil bacterial community structure of Chinese seabuckthorn were explored. The results showed that: (1) The number of amplicon sequence variants (ASVs) in rhizosphere soil bacterial community of Chinese seabuckthorn was the highest in S2(3072) and the S12(3637), and the lowest in the S11(1358) and S13(1996). The rhizosphere soil bacterial community was primarily composed of Proteobacteria, Actinobacteriota, and Acidobacteriota. Except for the S6 and S11 habitats, the dominant bacterial genera were mainly Achromobacter, Acidobacter (RB41), and Sphingomonas. (2) The α and β diversity of rhizosphere soil bacterial communities of Chinese seabuckthorn across 13 distribution areas were significantly different. The number of operational taxonomic units (OTUs), Ace index, and Chao 1 index of soil bacterial community in the S12 distribution area are the highest, and they are the lowest in S11 distribution area, with significant differences. The aggregation of soil bacterial communities in the S5 and S10 distribution areas is the highest, while it is the lowest in the S6 and S11 distribution areas. (3) PICRUSt function classification of soil bacteria showed that Metabolism and Genetic Information Processing functions were the strongest across all distribution areas, with S10 exhibiting higher functional capacity than other areas and S11 showing the weakest. (4) Cluster analysis revealed that soil bacteria across the 13 distribution areas were clustered into two groups, with S10 and S12 distribution areas as one group (Group 1) and the remaining 11 distribution areas as another group (Group 2). (5) Redundancy analysis revealed that pH was the key soil environmental factor driving the rhizosphere soil bacterial community α-diversity of Chinese seabuckthorn, followed by altitude (ALT) and soil water content (SWC). In summary, Chinese seabuckthorn prefers neutral to alkaline soils, and environmental factors play an important role in driving bacterial diversity, community structure, functional profiles, and co-occurrence networks in rhizosphere soil of Chinese seabuckthorn.

We conducted experiments to screen annual forage oats suitable for cultivation at high altitude (4200 m), and to establish a green fertilization system with microbial fertilizers and manure organic fertilizers in order to provide technical support for a sustainable forage production system in the pastoral areas of the Qinghai–Tibetan Plateau. The experiment followed the principle of randomized block design to systematically analyze the agronomic traits, yield quality, and soil health of oats among different treatments, and to screen for adaptable oat varieties and the optimal application rate of microbial fertilizers with organic manure. The results showed that the following: (1) The results of the oat variety screening test showed that the yield and quality indexes of ‘Qing Yin No. 2’ and ‘Bai Yan No. 7’ introduced in high altitude areas were higher than those of other oat varieties, with high membership function values of 0.69 and 0.65, respectively. (2) The combined application of microbial fertilizer and organic fertilizer showed that the combined application could significantly improve the growth and photosynthetic characteristics of ‘Bai Yan No. 7’. The combination of the two also improved the yield quality of ‘Bai Yan No. 7’; the hay yield with the BHC3 treatment was 8508.00 kg·hm⁻², significantly higher than the BCK treatment (p < 0.05). Regarding soil fertility, under the BHC3 treatment, compared with the BCK, soil nutrient contents and soil enzyme activities were also significantly improved (p < 0.05). At the same time, the combination of the two treatments also significantly improved the growth and photosynthetic characteristics of ‘Qing Yin No. 2’. The combination of the two also improved the yield quality of ‘Qing Yin No. 2’, and the hay yield with the QDY4 treatment was 8707.67 kg·hm⁻², which was significantly increased by 25.37%, compared with that of QCK. Regarding soil fertility, under the QHC2 treatment, compared with the QCK treatment, soil nutrient contents and soil enzyme activities were also significantly improved. To sum up, ‘Qing Yin No. 2’ and ‘Bai Yan No. 7’ can better adapt to the ecological environment in high altitude areas, and are suitable for planting in areas with an altitude of 4200 m. The combined application of Trichoderma harzianum, Bacillus licheniformis, and organic fertilizer can improve the yield, nutritional quality, and soil fertility of ‘Qing Yin No. 2’ and ‘Bai Yan No. 7’. The best treatment for ‘Qing Yin No. 2’ is QDY4, that is, 15.00 kg of Bacillus licheniformis is applied per hectare, and 18,000 kg of cattle and sheep manure organic fertilizer is applied per hectare. The best treatment for ‘Bai Yan No. 7’ is BHC3, that is, 6.00 kg of Trichoderma harzianum is applied per hectare, and 18,000 kg of cattle and sheep manure organic fertilizer is applied per hectare. With the above treatment, the forage grass grows best, the soil nutrient content in the forage grass field is the highest, and the input–output ratio is the highest.

This study aims to reveal the impact mechanisms of five typical topographic habitats in the Sanjiangyuan region (sunny slope, depression, shady slope, mountain pass, and transitional zone) on the characteristics and functions of rhizosphere soil fungal communities of Kengyilia thoroldiana, and to elucidate the association patterns between these communities and soil physicochemical factors. The species composition, diversity, molecular co-occurrence network, and FUNGuild function of microbial communities were investigated based on high-throughput sequencing technology. By combining the Mantel test and RDA analysis, the key habitat factors affecting the structure of the soil fungal community in the rhizosphere zone of Kengyilia thoroldiana were explored. The results showed that: ① The composition of the soil fungal community in the rhizosphere of Kengyilia thoroldiana in five topographical habitats showed significant differentiation characteristics: the number of OTUs in H2 (depression) and H5 (transitional zone) habitats was the highest (336 and 326, respectively). Habitats H2 showed a significant increase in the abundance of Ascomycota and Mortierellomycota and a significant decrease in the abundance of Basidiomycota compared to the other topographical habitats. ② The diversity and aggregation degree of the soil fungal community in the rhizosphere of Kengyilia thoroldiana in five topographical habitats showed differences. ③ Cluster analysis showed that the rhizosphere soil fungi in five topographical habitats of Kengyilia thoroldiana could be divided into two groups, with H2, H4 (mountain pass), and H5 habitats as one group (group 1) and H1 and H3 (shady slope) as one group (group 2). ④ The characteristics of the Kengyilia thoroldiana community and the physical and chemical properties of rhizosphere soil in five topographical habitats were significantly different, and the height, coverage, biomass, and soil nutrient content were the highest in H2 and H5 habitats, while lower in H1 and H3 habitats, with significant differences (p < 0.05). ⑤ Redundancy analysis showed that soil water content was the main driving factor to change the structure and function of the soil fungal community in the rhizosphere of Kengyilia thoroldiana in five topographic habitats in the Sanjiangyuan region. This study demonstrated that topographic habitats affected the species composition, functional pattern, and ecosystem service efficiency of the Kengyilia thoroldiana rhizosphere fungal community by mediating soil environmental heterogeneity, which provides microbial mechanistic insights for alpine meadow ecosystem protection.

This study aims to evaluate the restoration effect of artificially mixed-sown grasslands by investigating the characteristics of plant communities and soil fungal communities in long-term (22-year-established) artificial grasslands under six Poaceae mixture combinations. The experiment took mixed-sown grasslands of grass species established in 2002 on the Qinghai–Tibet Plateau as the research object. It employed ITS gene high-throughput sequencing technology to construct a fungal community distribution map and combined it with FUNGuild (Functional Guilds of Fungi) functional predictions to analyze fungal species abundance, structural diversity, molecular co-occurrence networks, and functional characteristics. By integrating Mantel test and RDA (redundancy analysis), we identified key environmental factors driving soil microbial community structure in mixed-sown grasslands and revealed the plant–soil–microbe interaction mechanisms in a Poaceae mixture grassland. The results showed that the HC treatment (a mixture of three grass species) significantly enhanced plant biomass and soil nutrient accumulation. In 2023 and 2024, its aboveground biomass increased by 66.14% and 60.91%, respectively, compared to the HA treatment (monoculture). Soil organic matter increased by 52.32% and 48.35%, while electrical conductivity decreased by 48.99% and 51.72%, respectively. The fungal community structure improved under the HD treatment (a mixture of four grass species), with an increased abundance of the dominant phylum Ascomycota and a 14.44% rise in the Shannon index compared to the HA treatment. The network complexity under the HF treatment (a mixture of six grass species) increased (with edge numbers reaching 494), while the functional abundance of plant pathogen was significantly lower than that under the HA treatment. Mantel test and RDA revealed that SEC (soil electrical conductivity) was significantly positively correlated with pH, while both exhibited negative correlations with other plant and soil physicochemical indicators. Moreover, SEC emerged as the core factor driving fungal community assembly. Mixed sowing of three to four grass species effectively regulated soil electrical conductivity, simultaneously enhancing plant biomass, soil nutrients, and fungal community diversity, representing an optimal strategy for artificial restoration of degraded grasslands.