土地集约利用程度对华北潮土农田土壤微生物群落丰度和死生物物质积累的影响

土壤微生物决定着土壤生态系统的养分周转状况，其死生物物质在土壤有机碳(SOC)积累中发挥关键作用.然而，目前缺乏对土壤微生物群落丰度及其死生物物质如何响应农业土地集约利用程度调整的了解.为弥补这一知识缺口，基于土地集约化利用程度，设置小麦-玉米周年轮作(CC)、临时草地与小麦种植交替(TG)和多年生草地(PG)这3个处理开展长期定位试验，采用基于数字PCR和微生物标志物氨基糖的检测技术，以探究农业土地集约利用程度调整对土壤细菌和真菌数量，以及细菌、真菌和总微生物死生物物质C积累及其对土壤SOC封存贡献的影响，进一步明确驱动细菌、真菌和总微生物死生物物质C积累的关键因子.结果表明，与土壤细菌群落丰度相比，真菌群落丰度受到农业土地集约利用程度调整的强烈影响，随土地集约利用程度的降低而增加.在3种土地集约利用程度处理下，土壤总微生物死生物物质C均主导SOC积累，对SOC的贡献率分别达到52.78%、 58.36%和68.87%,呈现随土地集约利用程度降低而升高的趋势；真菌死生物物质C占总微生物死生物物质C的比例均大于80%,说明其对总微生物死生物物质C的绝对主导地位，且受土地集约利用程度降低...

Impacts of Land Use Intensification Level on Fluvo-aquic Cropland Soil Microbial Community Abundance and Necromass Accumulation in North China

Despite the essential role of soil microorganisms in nutrient turnover in soil ecological systems and the recognized paramount significance of microbial necromass to soil organic carbon accumulation, how microbial community abundance and necromass respond to land use intensification level regulation remains poorly understood. To address this knowledge gap, based on the land use intensification level, three treatments were set upannual wheat-maize rotation (CC), alternating temporary grassland with wheat planting (TG), and perennial grassland (PG)], and a long-term fixed filed experiment was established to investigate the influences of the regulation of land use intensification level on bacterial and fungal community abundances; the accumulation of bacterial, fungal, and total microbial necromass; and their contributions to SOC sequestration using droplet digital PCR and amino sugar detection technologies. We further sought to determine the key factors driving the bacterial, fungal, and total microbial necromass C accumulation. Our results demonstrated that fungal community abundance was strongly affected by land use intensification level regulation compared to that of the bacterial community, which increased with decreasing land use intensification level. The total microbial necromass C predominated the SOC accumulation across all three land use intensification levels, which contributed 52.78%, 58.36%, and 68.87% to SOC, respectively, exhibiting an increasing trend with the decline in land use intensification level. Fungal necromass C accounted for more than 80% of the total microbial necromass C, indicating its predominance in the accumulation of the total microbial necromass C and active variation via the reduction in land use intensification level. There was no significant difference in bacterial necromass C (MurA) content, with the trend of CC