Land conversion to agriculture is an important factor affecting soil ecological processes in the desert grasslands of northern China. However, soil fungal-community structure and function in response to Land conversion remain unclear. In this study, desert grassland, artificial shrubland, and land conversion were investigated in the western part of the Mu Us Sandland (Yanchi, Ningxia; Dingbian, Shaanxi). We found that land conversion significantly increased soil total carbon, nitrogen, and phosphorus, and available phosphorous and potassium contents. In the early stage of conversion to agricultural (April), soil fungal operational taxonomic units and abundance-based coverage estimator were lower than those of dessert grasslands and shrubland plots and had significant correlations with pH, electric conductivity, and available phosphorus and potassium. The dominant phyla strongly correlated with soil physicochemical properties. Concomitantly, the relative abundance of Glomeromycota was significantly lower, and the complexity of the network in the land conversion plots was lower than that in the shrubland plots. In the late stage of land conversion (September), soil fungal operational taxonomic units and abundance-based coverage estimator were lower in the conversion plots than in the desert grassland plots, with more complex network relationships compared to the desert grassland or shrubland plots. Symbiotrophic groups, a functional group of desert grassland soil fungi, can be used as a predictor of environmental change; in addition, land conversion decreases the relative abundance of arbuscular mycorrhizal functional groups. Our study highlights the response of soil fungal communities and functions to human disturbances in desert grasslands. Considering the potential of land conversion to agriculture to influence soil secondary salinization, there is a need for continued observation of soil ecological health over the time continuum of land conversion to agriculture.

Microbial communities constitute a diverse genetic resource pool in the soil and are key indicators of soil health and quality. How re-vegetation affects soil microbial diversity and community composition at the dump of an opencast coal mine is largely unknown. Using high-throughput sequencing, we performed a comparative study of the bacterial and fungal communities from non-vegetated (bare land) soil and from areas re-vegetated by Astragalus laxmannii, Halogeton arachnoideus, and Artemisia desertorum at an opencast coal mine in the Helan Mountains in western China. These results indicated that re-vegetation significantly reduced soil conductivity. The soils re-vegetated by all three plant species showed greater richness of bacterial species than the bare land, and soils re-vegetated with A. desertorum and A. laxmannii showed significantly greater richness of fungal species than bare land. The bacterial and fungal β-diversity values differed significantly between vegetated and non-vegetated soil, and these differences were more pronounced for bacterial communities than for fungal communities. Re-vegetation significantly increased the relative abundances of Proteobacteria and Bacteroidota and decreased the relative abundance of Chloroflexi. The decreasing soil conductivity that occurred with re-vegetation was found to be an important environmental determinant of the soil microbial community. This study provides evidence that re-vegetation may enhance soil quality via decreasing soil conductivity and altering the soil microbial community, and A. laxmannii was found to be a more effective species than H. arachnoideus or A. desertorum with respect to decreasing soil conductivity and altering the soil microbial communities in the Opencast Coal Mine arid region. This work may provide a helpful guideline for selection of plant species for re-vegetation projects.

Wetlands occupy a mere 6% of Earth’s land surface, yet they contribute 25–45% of global natural methane (CH₄) emissions. A key contradiction emerges here: it is the soil of these wetlands that serves as the host for methane-trophic microorganisms, which can oxidize the vast majority of the methane they produce under specific conditions (for example, the aerobic interface). A wetland’s role as either a net source or sink for atmospheric CH₄ is therefore a primary driver of hydrological variability. This research synthesis current understandings of how wet–dry cycles regulate methanotrophic communities and their CH₄ consumption capacity. Shifts in the water table directly modulate methanotroph physiology, community structure, and metabolic activity. These hydrological effects are further amplified or attenuated by nitrogen availability, plant-derived exudates, and edaphic properties. Herein, key knowledge gaps concerning the adaptive responses of methanotrophs to hydrological change are identified, and targeted research priorities improving predictions of wetland CH₄ fluxes under contrasting moisture regimes are accordingly outlined. This review synthesizes recent advances to highlight the mechanistic understanding essential for guiding wetland management strategies.

The rapid global plant diversity and productivity loss has resulted in ecosystem functional degeneration in recent decades, and the relationship between plant diversity and productivity is a pressing issue around the world. Here, we sampled six plant communities that have not been grazed for 20 years, i.e., Agropyron mongolicum, Stipa bungeana, Cynanchum komarovii, Glycyrrhiza uralensis, Sophora alopecuroides, Artemisia ordosica, located in a desertified steppe, northwestern China, and tested the relationship between plant diversity and productivity in this region. We found a positive linear relationship between AGB (above-ground biomass) and BGB (below-ground biomass), and the curves between plant diversity and AGB were unimodal (R² = 0.4572, p < 0.05), indicating that plant productivity increased at a low level of diversity but decreased at a high level of diversity. However, there was no significant relationship between BGB and plant diversity (p > 0.05). Further, RDA (redundancy analysis) indicated that soil factors had a strong effect on plant diversity and productivity. Totally, GAMs (generalized additive models) showed that soil factors (especially total nitrogen TN, total carbon TC, soil microbial biomass nitrogen SMB-N, soil microbial biomass carbon SMB-C) explained more variation in plant diversity and productivity (78.24%), which can be regarded as the key factors driving plant diversity and productivity. Therefore, strategies aiming to increase plant productivity and protect plant diversity may concentrate on promoting soil factors (e.g., increasing TC, TN, SMB-N and SMB-C) and plant species, which can be regarded as an effective and simple strategy to stabilize ecosystems to mitigate aridity in desertified steppes in northwestern China.