Simulating the effect of climate change on soil microbial community in an Abies georgei var. smithii forest

"Harnessing the power of soil microbes: Their dual impact in integrated nutrient management and mediating climate stress for sustainable rice crop production" A systematic review

Sustainable agricultural practices are essential to meet food demands for the increased population while minimizing the environmental impact. Considering rice as staple food for most of the world's population, it requires innovative approaches to ensure sustainable production. In this paper, we create a hypothesis that integrated nutrient management (INM) acts as a source of energy for microbes and improves the physical, chemical and biological properties of soils, but the current understanding of how soil microbiomes interact in integrated nutrient management toward mediating climate stress to support sustainable rice crop production is limited. Hence, we develop literature search through Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to explore the hidden knowledge related to that question. The outcomes of the study are postulated as a viable option to minimize excessive chemical fertilizers and promote organic-based nutrient management that directly impacts microbial consortia. This review uncovered that plant-microbe interactions and nutrient transformation depend heavily on soil microbes while the abundance, diversity, and activity of soil microbiome is enhanced more with integrated nutrient management than with sole synthetic fertilizers. Through their ability to enhance nutrient availability and uptake, improve soil structure, heavy metal detoxification, salinity and drought tolerance, and suppress pathogens, they can alleviate abiotic stress associated with climate change. Therefore, optimization of microbial communities serves as a potential mechanism for INM to enhance rice yield and mitigate climate stress. This would improve soil health and enhance the resilience of the rice plant to climate change. However, despite various benefits obtained through INM and microbes in paddy production systems, the literature indicated that adoption of this technology is limited to smallholder farmers due to lack of knowledge, unavailability of sufficient organic materials and poor understanding of the long-term impacts associated with over-application of chemical fertilizers. Therefore, scientists must translate several research discoveries related to sustainable agriculture into simple language that can be adopted by farmers and future research should be a farmers-participatory approach to generate awareness investments and knowledge of farmers in adopting sustainability measures. Additionally, research could focus on identifying mechanisms by which microbiomes improve nutrient uptake and rice growth and how these mechanisms can be optimized through integrated nutrient management strategies with regard to climate stresses.

Distribution characteristics of soil active organic carbon at different elevations and its effects on microbial communities in southeast Tibet

Global mountain ecosystems have garnered significant attention due to their rich biodiversity and crucial ecological functions; however, there is a dearth of research on the variations in soil active organic carbon across altitudinal gradients and their impacts on microbial communities. In this study, soil samples at an altitude of 3,800 m to 4,400 m were collected from Sejira Mountain in the southeast Tibet, and soil active organic carbon components, soil microbial community diversity, composition and structure distribution and their relationships were systematically analyzed. The results revealed a non-linear relationship between the elevation and the contents of soil organic carbon (SOC) and easily oxidized organic carbon (ROC), with an initial increase followed by a subsequent decrease, reaching their peak at an altitude of 4,200 m. The Shannon diversity of bacteria exhibited a significant decrease with increasing altitude, whereas no significant change was observed in the diversity of fungi. The bacterial community primarily comprised Acidobacteria, Proteobacteria, Chloroflexi, and Actinobacteriota. Among them, the relative abundance of Proteobacteria exhibited a negative correlation with increasing altitude, whereas Actinobacteriota demonstrated a positive correlation with elevation. The fungal communities primarily consisted of Basidiomycota, Ascomycota, and Mortierellomycota, with Ascomycota prevailing at lower altitudes and Basidiomycota dominating at higher altitudes. The diversity and composition of bacterial communities were primarily influenced by altitude, SOC, ROC, and POC (particulate organic carbon). Soil carbon-to-nitrogen ratio (C/N), dissolved organic carbon (DOC), and available phosphorus (AP) emerged as key factors influencing fungal community diversity, while POC played a pivotal role in shaping the composition and structure of the fungal community. In conclusion, we believe that soil active organic carbon components had a greater impact on the bacterial community in the primary forest ecosystem in southeast Tibet with the elevation gradient increasing, which provided a theoretical basis for further understanding of the relationship between the microbial community and soil carbon cycle in the plateau mountain ecosystem under the background of climate change.

Archaeal communities change responding to anthropogenic and natural treatments of freeze-thawed soils

The coverage of accumulated snow plays a significant role in inducing changes in both microbial activity and environmental factors within freeze-thaw soil systems. This study aimed to analyze the impact of snow cover on the dynamics of archeal communities in freeze-thaw soil. Furthermore, it seeks to investigate the role of fertilization in freeze-thaw soil. Four treatments were established based on snow cover and fertilization:No snow and no fertilizer (CK-N), snow cover without fertilizer (X-N), fertilizer without snow cover (T-N), and both fertilizer and snow cover (T-X). The research findings indicated that after snow cover treatment, the carbon, nitrogen, and phosphorus content in freeze-thaw soil exhibit periodic fluctuations. Snow covered effectively altered the community composition of bacteria and archaea in the soil, with a greater impact on archaeal communities than on bacterial communities. Snow covered improves the stability of archaeal communities in freeze-thaw soil. Additionally, the arrival of snow also enhanced the correlation between archaea and environmental factors, with the key archaeal phyla involved being Nanoarchaeota and Crenarchaeota. Further research showed that the application of organic fertilizers also had some impact on freeze-thaw soil, but this impact was smaller compared to snow cover. In summary, the arrival of snow could alter the archaeal community and protect nutrient elements in freeze-thaw soil, reducing their loss, and its effect is more pronounced compared to the application of organic fertilizers.

Elevational distribution patterns and drivers factors of fungal community diversity at different soil depths in the Abies georgei var. smithii forests on Sygera Mountains, southeastern Tibet, China

Introduction

Soil fungal communities play a crucial role in maintaining the ecological functions of alpine forest soil ecosystems. However, it is currently unclear how the distribution patterns of fungal communities in different soil layers of alpine forests will change along the elevational gradients.

Material and methods

Therefore, Illumina MiSeq sequencing technology was employed to investigate fungal communities in three soil layers (0-10, 10-20, and 20-30 cm) along an elevational gradient (3500 m to 4300 m) at Sygera Mountains, located in Bayi District, Nyingchi City, Tibet.

Results and discussion

The results indicated that: 1) Soil depth had a greater impact on fungal diversity than elevation, demonstrating a significant reduction in fungal diversity with increased soil depth but showing no significant difference with elevation changes in all soil layers. Within the 0-10 cm soil layer, both Basidiomycota and Ascomycota co-dominate the microbial community. However, as the soil depth increases to 10-20 and 20-30 cm soil layers, the Basidiomycota predominantly dominates. 2) Deterministic processes were dominant in the assembly mechanism of the 0-10 cm fungal community and remained unchanged with increasing elevation. By contrast, the assembly mechanisms of the 10-20 and 20-30 cm fungal communities shifted from deterministic to stochastic processes as elevation increased. 3) The network complexity of the 0-10 cm fungal community gradually increased with elevation, while that of the 10-20 and 20-30 cm fungal communities exhibited a decreasing trend. Compared to the 0-10 cm soil layer, more changes in the relative abundance of fungal biomarkers occurred in the 10-20 and 20-30 cm soil layers, indicating that the fungal communities at these depths are more sensitive to climate changes. Among the key factors driving these alterations, soil temperature and moisture soil water content stood out as pivotal in shaping the assembly mechanisms and network complexity of fungal communities. This study contributes to the understanding of soil fungal community patterns and drivers along elevational gradients in alpine ecosystems and provides important scientific evidence for predicting the functional responses of soil microbial ecosystems in alpine forests.

Reforestation of Cunninghamia lanceolata changes the relative abundances of important prokaryotic families in soil

Over the past decades, many forests have been converted to monoculture plantations, which might affect the soil microbial communities that are responsible for governing the soil biogeochemical processes. Understanding how reforestation efforts alter soil prokaryotic microbial communities will therefore inform forest management. In this study, the prokaryotic communities were comparatively investigated in a secondary Chinese fir forest (original) and a reforested Chinese fir plantation (reforested from a secondary Chinese fir forest) in Southern China. The results showed that reforestation changed the structure of the prokaryotic community: the relative abundances of important prokaryotic families in soil. This might be caused by the altered soil pH and organic matter content after reforestation. Soil profile layer depth was an important factor as the upper layers had a higher diversity of prokaryotes than the lower ones (p < 0.05). The composition of the prokaryotic community presented a seasonality characteristic. In addition, the results showed that the dominant phylum was Acidobacteria (58.86%) with Koribacteraceae (15.38%) as the dominant family in the secondary Chinese fir forest and the reforested plantation. Furthermore, soil organic matter, total N, hydrolyzable N, and NH 4 + - N were positively correlated with prokaryotic diversity (p < 0.05). Also, organic matter and NO 3 - - N were positively correlated to prokaryotic abundance (p < 0.05). This study demonstrated that re-forest transformation altered soil properties, which lead to the changes in microbial composition. The changes in microbial community might in turn influence biogeochemical processes and the environmental variables. The study could contribute to forest management and policy-making.

Effects of simulated warming on soil microbial community diversity and composition across diverse ecosystems

Soil warming can directly affect the microbial community, or indirectly affect the microbial community by affecting soil moisture, nutrient availability, vegetation growth, etc. However, the response of microorganisms to soil warming is complex, and there is no uniform conclusion on the impact and mechanism of warming on microbial diversity. As the global climate gradually warms, a comprehensive assessment of warming on soil microbial community changes is essential to understand and predict the response of microbial geochemical processes to soil warming. Here, we perform a meta-analysis of studies to investigate changes in soil microbial communities along soil warming gradients and the response of soil microbes to elevated temperature in different ecosystems. We found that the α diversity index of soil microorganisms decreased significantly with the increase in temperature, and the β diversity altered with the increase in soil temperature and the shifts in ecosystem. Most bacteria only alter when the temperature rises higher. Compared to the non-warming condition, the relative abundance of Acidobacteria, Proteobacteria, Bacteroidetes, Planctomycetes and Verrucomicrobia decreased by 19 %, 11 %, 19 %, 8 % and 6 %, respectively, and the relative abundance of Firmicutes increased by 34 %. Compared to farmland, forest, grassland and tundra ecosystems, soil microorganisms in wetland ecosystems were more sensitive to temperature increase, and the changes in bacteria were consistent with the overall alterations. This meta-analysis revealed significant changes in the composition of microbial communities on soil warming. With the decrease in biodiversity under increasing temperature conditions, these dominant microbiomes, which can grow well under high-temperature conditions, will play a stronger role in regulating nutrient and energy flow. Our analysis adds a global perspective to the temperature response of soil microbes, which is critical to improving our understanding of the mechanisms of how soil microbes change in response to climate warming.