生物结皮提升红壤区崩壁土壤多功能性的养分-微生物途径OA

[Objective]This study aims to elucidate the specific mechanisms by which biocrusts drive the recovery of soil multifunctionality in extremely degraded habitats in the red soil erosion area.[Methods]Typical collapsing walls in Fujian Province were selected as the research object.Soil samples of bare soil,algal biocrusts,and moss biocrusts were collected to determine soil nutrient contents and key enzyme activities.High-throughput sequencing and path analysis were employed to decipher the driving pathway of biocrusts-nutrient environment-microbial characteristics-soil multifunctionality.[Results]1)Different types of biocrusts significantly enhanced the soil multifunctionality of collapsing walls,exhibiting a clear gradient of moss biocrusts＞algal biocrusts＞bare soil.Under moss biocrust treatment,the contents of soil organic carbon,total nitrogen,and alkali-hydrolyzable nitrogen reached their maximum,and the multifunctionality index was significantly higher than those of algal biocrust and bare soil treatments.2)Total nitrogen(R2=0.78),alkali-hydrolyzable nitrogen(R2=0.82),and urease(R2=0.83)were the core drivers supporting the improvement of soil multifunctionality.3)Biocrusts(especially moss biocrusts)significantly increased the Shannon diversity index of the bacterial community and the gene abundance of metabolic functional potentials related to carbohydrates and amino acids.Bacterial diversity and functional potential showed a highly significant positive correlation with soil multifunctionality(p＜0.01),while the functional contribution of the fungal community was relatively weak.4)Path analysis revealed that biocrusts enhanced soil multifunctionality primarily by improving the soil nutrient environment(direct effect accounting for 89.50％).Although microbial characteristics responded significantly to the improvement of nutrient conditions,their direct driving effect on integrated functions did not fully manifest in the current habitat(contributing only 10.50％).[Conclusion]Biocrusts effectively promote the synergistic recovery of soil functions on collapsing walls through the core pathway of biocrust succession-nutrient environment improvement-multifunctionality enhancement.In the management of Benggang erosion in the red soil region,artificial inoculation of biocrusts and promotion of their succession toward the moss stage represent an effective strategy for accelerating the ecological restoration of collapsing wall soils.