Intensively managed Camellia oleifera plantations with acidified soil rely on nitrogen (N) fertilizers for high yields, but this accelerates soil acidification and boosts emissions of nitric oxide (NO) and nitrous oxide (N₂O), endangering long-term sustainability. Green manure (GM) serves as an eco-friendly alternative, improving soil fertility and increasing ecosystem carbon and N inputs. However, the effects of GM species, legumes (Leg), gramineous (Gra), and their mixture (Leg-Gra) with residue incorporation on soil acidification and NO/N₂O fluxes remain unclear. To clarify the mechanisms underlying GM intercropping with residue incorporation on soil NO and N₂O emissions, we conducted an in situ study in intensively managed C. oleifera plantation ecosystems intercropping Leg, Gra, and Leg-Gra, or managed with N, manual weeding and natural grass to investigate how GM intercropping with residue incorporation influences soil acidification and NO/N₂O emissions. 1) GM intercropping with residue incorporation reduced both NO and N₂O emission rates compared to N. Specifically, Leg, Gra and Leg-Gra intercropping reduced the emission rates of N₂O by 24.83%, 46.06% and 35.64% compared to N, respectively. 2) GM intercropping reduced the abundance of AOA and AOB genes, increases the abundance of nosZ, and decreases NO and N₂O emissions. 3) Leg-Gra intercropping with residue incorporation increased soil organic carbon (SOC) by 9.96% and raised soil pH to 4.89, representing a 5.81% increase over N treatment. 4) Leg-Gra increased the decomposition rate of leguminous GM, accelerating nutrient release. Legume-gramineous intercropping effectively mitigates soil acidification, enhances SOC, and curbs NO/N₂O emissions, offering a sustainable strategy for acidic agroforestry soils.

Coastal wetlands are experiencing long-term plant invasions, which pose a significant impact on the soil microbiome. However, the latitudinal diversity patterns of soil microbiome in blue carbon ecosystems under plant invasion remain poorly understood. In this study, 12 sample sites spanning over 2000 km were established along China’s coastlines, with paired mudflat and Spartina alterniflora-invaded habitats. Soil (mudflat sediments included, termed “soil” for consistency) bacterial diversity was assessed across topsoil, subsoil, and deep soil layers. In mudflat habitats, bacterial richness generally increased with latitude. In contrast, S. alterniflora invasion altered this pattern to a hump-shaped distribution. This shift was most pronounced in the topsoil compared to the subsoil and deep soil layers, a consistent trend across the dominant taxa. Additionally, plant invasion accelerated the spatial turnover of bacterial communities in the topsoil, but not in deeper layers. Environmental variables, including soil temperature and salinity, were the predominant factors shaping these latitudinal diversity patterns. Structural equation models revealed that soil temperature, rather than soil depth, was the primary direct driver of bacterial richness, and plant invasion reduced the influence of soil depth on this relationship. Overall, our study revealed that invasive plant regimes profoundly restructured the latitudinal diversity pattern of soil microbiomes, particularly in the topsoil. This study broadens our understanding of how plant invasion affects soil microbial biogeography and its underlying drivers in blue carbon ecosystems.

Plastic pollution, a defining symptom of our planet’s unsustainable linear “take-make-dispose” economy, presents a critical challenge to ecosystem health and sustainable development. Terrestrial ecosystems, particularly soils, have become the primary sink for microplastic contamination, where these pollutants form novel “Soil Plastisphere” habitats that disrupt essential biogeochemical cycles and threaten soil integrity. This cross-disciplinary, synthetic review assesses the potential of microbial biodegradation as a key biotechnological tool for sustainable plastic waste management and the development of a circular economy. We first evaluate the variable impacts of the plastisphere on soil health, providing a crucial baseline for understanding the ecological risks and informing sustainability policies. We then examine the core biochemical pathways of plastic degradation, highlighting the remarkable diversity of novel catalysts—such as thermophilic PETases, cutinases and the crucial extracellular oxidoreductases secreted by fungi to initiate the breakdown of recalcitrant polymers—discovered through metagenomics. Finally, we survey the frontier of biotechnology, reviewing advanced strategies that move beyond simple degradation, such as the rational engineering of hyper-efficient enzymes, the development of reusable whole-cell biocatalysts, and the “upcycling” of plastic waste into valuable bioproducts—including polyhydroxybutyrate (PHB). Despite these advances, critical knowledge gaps remain, particularly regarding the enzymatic cleavage of highly recalcitrant polyolefins and the translation of laboratory-scale successes to complex field conditions; overcoming these bottlenecks will be essential for developing robust, biologically-based solutions within a circular materials economy.

Biochar has emerged as a promising carrier for microbial inoculants, yet its capacity to enhance inoculant persistence while preserving native soil microbial communities remains insufficiently documented. This study evaluated an olive-pomace-derived biochar as a carrier for Bacillus velezensis and Trichoderma virens in a Mediterranean Cambisol under controlled conditions. Biochar supported high initial microbial loadings (>10⁸ CFU or spores g⁻¹ biochar), strong short-term viability (76–88%), and clear colonization of pore surfaces as observed by scanning electron microscopy. Following a 30-day pot incubation, biochar-based inoculation enhanced microbial persistence compared with direct soil application, maintaining recoverable inoculant populations close to or above initial levels. Findings revealed that biochar maintained community-level structural and functional patterns at the resolution detectable by fingerprinting and metabolic profiling approaches. These results suggest that biochar functioned primarily as a physical carrier, providing protected microsites that may have contributed to the stabilization of introduced microorganisms while maintaining overall soil functional diversity. Our findings demonstrate that olive-pomace biochar can be valorized as an effective microbial carrier, suited to Mediterranean soils where early inoculant establishment is often constrained. Future research should assess the durability of these mechanisms under field conditions to determine their long-term relevance for soil biological functioning and restoration.

Land-use change is increasingly altering the structure and function of soil fauna. However, how forest conversion shapes the functional composition and diversity of soil nematode communities is still poorly understood in subtropical forests. This study investigated the response of soil nematode communities to the conversion of natural forests into chestnut (Castanea henryi) plantations, with particular attention to the role of slope aspect in subtropical forest ecosystems. Our results showed that converting natural forests into chestnut plantations led to a pronounced reduction in soil nematode density, diversity (Shannon–Wiener index), and genus richness by 67.6%, 12.2%, and 24.4%, respectively, particularly on north-facing (shady) slopes. Additionally, soil nematode co-occurrence networks in chestnut plantations were reduced robustness compared with natural forests by 60.7%. South-facing (sunny) slopes increased total nematode and omnivore-predator abundance by 36.9% and 71.9%, respectively, and amplified the negative impact on herbivorous nematodes from land conversion. These findings emphasize the critical role of considering slope aspect in chestnut plantation management to mitigate negative impacts on soil nematode communities and maintain soil health in subtropical forests.

Microbial life-history strategies are fundamental to predicting community assembly and ecosystem function, yet they are often distilled to a single axis—the copiotroph-oligotroph continuum—that couples fast growth with large genomes and slow growth with small genomes. Whether this one-dimensional view captures the full diversity of bacterial strategies in soil remains untested at population level. Here, we couple genome-resolved metagenomics with trait-based inference to examine how genome size and maximum growth rate—two core life-history traits—co-vary across 321 bacterial populations from 67 soils spanning gradients in pH and organic carbon. We find that genome size and growth rate are only weakly correlated, allowing the identification of four contrasting life-history strategy groups defined by extreme combinations of genome size and growth potential: Small-Fast, Small-Slow, Large-Fast, and Large-Slow. Genome size is strongly phylogenetically conserved and defines the breadth of functional potential, whereas growth rate is more evolutionarily labile and differentiates strategies through targeted investments in biosynthetic pathways (e.g., amino acid metabolism). Environmental filtering shapes specific strategy combinations rather than single traits: compact genomes with high growth potential (Small-Fast) are selected in alkaline, low-carbon soils, while the Large-Slow strategy characterized by expanded genomes with slow growth shows elevated relative abundance in acidic, carbon-rich soils relative to alkaline, low-carbon conditions. Our findings challenge the prevailing copiotroph-oligotroph continuum by demonstrating that bacterial life-history strategies are inherently multidimensional. By decoupling genome size from growth potential, this framework provides a more predictive basis for understanding how environmental filtering shapes microbial life-history strategies and functional potential across soil ecosystems.