Dynamics of agricultural soil fungi: Impact of agricultural land management on soil microbial biomass, fungal taxonomic richness and ligninolytic gene distribution.

摘要

Understanding the impact of human activity on environmental microbiota and their ecosystem processes is essential to formulating and employing a sustainable approach to agriculture. To that end, we examined how eight different agronomic land management strategies impacted the overall biomass of the microbiota inhabiting Midwestern United States soils, comparing this data with the microbial biomass of a nearby mid-successional field and two nearby forested sites. We further examined how agricultural land management practices impacted the taxonomic structure and genetic potential for lignolytic activity of the fungi residing in the soils of two 3-crop agricultural rotations, one under conventional till and the other under no till management. We compared the taxonomic structures and ligninolytic potentials of the agricultural treatments to each other and to those of soils of a nearby, deciduous forest, the native terrestrial ecosystem from which the agronomic treatments originated and an early-successional treatment that was historically under agronomic management but abandoned from agriculture 22 years prior. We found that the particular agricultural land management employed had a significant impact on the microbial biomass of the soils from each treatment. Further, we found that although land management did not significantly affect the Operation Taxonomic Unit (OTU) richness of soil fungi in the till and no-till treatments, when compared to the fungal communities of the early-successional and native forest soil fungal communities, it did strongly impact how the fungal communities in each treatment were structured in terms of OTU membership. Lastly, although land management practices did not make a statistically significant difference in the total number of lignolytic genes detected in the fungal community from each treatment, it did make a significant difference in the ligninolytic gene structure of each treatment.