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Purpose: The overall production of degraded grassland ecosystems can be improved by reseeding appropriate species, but the responses of soil microbes to reseeded grassland after a long-term growth, especially the mediation effects of soil chemical compounds on the soil microbial community composition, have rarely been reported. Materials and methods: In this study, we reseeded a degraded grassland with Bromus inermis Leyss and investigated the changes in aboveground (grassland biomass) and belowground factors (soil properties, soil chemical compounds, soil microbial diversity, and community) under reseeded and non-reseeded treatments. Results and discussion: The reseeding of B. inermis significantly (P < 0.05) enchacecd the aboveground vegetative biomass by 22.72% as compared with the plots that were not reseeded. Significant (P < 0.05) differences were also observed in the soil chemical compounds and microbial diversity and community between the reseeded and non-reseeded treatments. Soil bacterial (R2 = 0.6271, P = 0.0007) and fungal α-diversity (R2 = 0.5895, P = 0.0013) were both positively correlated with grassland biomass. Moreover, the community compositons of soil bacterial (R = 0.465, P = 0.002) and fungal (R = 0.720, P = 0.001) also had significant correlations with grassland biomass. Actinoplanes, Streptomyces, Bacillus, and Mesorhizobium were identified as potential agents for promoting grassland growth. Network analysis showed that the assemblages of soil microbes in the reseeding treatment formed larger and more complex networks than those in the non-reseeding treatment. Conclusions: Our study, cutting in terms of soil microbial ecology, provides a valuable model for explaining the aboveground responses to the establishment of perennial grass species in degraded grasslands. [ABSTRACT FROM AUTHOR]

Backgrounds and aims: Mowing and P-fertilization enhance legume seedling establishment, assisting in successful restoration of degraded grasslands. Legume establishment may influence soil chemical compounds and soil microbial assemblage to facilitate legume productivity. We aim to better understand these complex plant-soil-microbial interactions to improve grassland productivity following overgrazing. Methods: We conducted a 3-years Medicago falcata reseeding experiment was in semi-arid meadows, assessing responses of aboveground plant biomass, soil chemical compounds, and soil microbial community composition. Reseeded plots were mowed and/or P-fertilized. Results: Application of both management practices increased grassland biomass compared with all other combinations. Soil chemical diversity predicted fungal alpha diversity, and fungal alpha diversity positively correlated with aboveground biomass. Our results indicate reseeded alfalfa directly altered bulk soil chemical compounds with subsequent alterations in grassland microbial communities. Soils contained chemical compounds with antifungal properties that indirectly improved grassland productivity via antagonism to pathogenic fungi. Furthermore, we found three specific compounds (5-methyltridecane, pentatriacontane, and N-tridecane) reduced microbial diversity. Conclusions: Here we demonstrate soil chemical compounds play an important role in shaping beneficial microbial communities to improve grassland biomass. These results may help direct beneficial soil microbial community composition through improved grassland management practices. [ABSTRACT FROM AUTHOR]

Bio-fertilizer application has been proposed as a strategy for enhancing soil fertility, regulating soil microflora composition, and improving crop yields, and it has been widely applied in the agricultural yields. However, the application of bio-fertilizer in grassland has been poorly studied. We conducted in situ and pot experiments to investigate the practical effects of different fertilization regimes on Leymus chinensis growth, with a focus on the potential microecological mechanisms underlying the responses of soil microbial composition. L. chinensis biomass was significantly (P < 0.05) increased by treatment with 6000 kg ha−1 of Trichoderma bio-fertilizer compared with other treatments. We found a positive (R2 = 0.6274, P < 0.001) correlation between bacterial alpha diversity and L. chinensis biomass. Hierarchical cluster analysis and nonmetric multidimensional scaling (NMDS) revealed that soil bacterial and fungal community compositions were all separated according to the fertilization regime used. The relative abundance of the most beneficial genera in bio-fertilizer (BOF) (6000 kg ha−1Trichoderma bio-fertilizer) was significantly higher than in organic fertilizer (OF) (6000 kg ha−1 organic fertilizer) or in CK (non-amend fertilizer), there the potential pathogenic genera were reduced. There were significant negative (P < 0.05) correlations between L. chinensis biomass and the relative abundance of several potential pathogenic genera. However, the relative abundance of most beneficial genera were significantly (P < 0.05) positively correlated with L. chinensis biomass. Soil properties had different effects on these beneficial and on these pathogenic genera, further influencing L. chinensis biomass. [ABSTRACT FROM AUTHOR]