Soil invertebrates, especially larger macroinvertebrates, move soil, fragment organic matter and change resource accessibility for soil microorganisms. Macroinvertebrates also affect the formation and turnover of aggregates, which are important controls of soil organic matter dynamics because they physically protect organic matter from degradation and influence many belowground processes ranging from microbial activity to nutrient sorption and water flow. We still lack a complete understanding of how different soil invertebrate functional groups affect the incorporation of root derived carbon and nitrogen into belowground pools. We assessed the effects of macroinvertebrates on soil aggregate abundance and composition and quantified the fate of organic matter derived from roots using a two-year macroinvertebrate exclusion-based field mesocosm study coupled with stable isotope labeling in a turfgrass lawn ecosystem. We hypothesized that macroinvertebrates change soil aggregates dynamics by increasing macroaggregates and decreasing microaggregates and enhancing the incorporation of root-derived organic matter into macroaggregates. We found that within the turfgrass root zone, macroinvertebrates increased the proportion of macroaggregates and decreased free microaggregates. In addition, macroinvertebrates increased carbon and nitrogen incorporation into macroaggregates, microaggregates and coarse particulate organic matter, detected via isotopic enrichment of those soil fractions. We found that macroinvertebrates affect the fate of recently fixed root- and rhizodeposit-derived organic matter in a turfgrass lawn ecosystem, and particularly its incorporation into soil aggregates, similar to findings in forest and agricultural systems.

土壤无脊椎动物，特别是大型无脊椎动物，会移动土壤，使有机物破碎，并改变土壤微生物的资源可及性。无脊椎动物还影响聚集体的形成和更新，聚集体是土壤有机质动态的重要控制因素，因为它们物理上保护有机质免于降解并影响许多地下过程，从微生物活性到养分吸收和水流。我们仍然对不同的土壤无脊椎动物功能组如何影响根源的碳和氮掺入地下池的情况缺乏完全的了解。我们进行了为期两年的基于大型无脊椎动物排斥的田间介观研究，并在草皮草坪生态系统中使用了稳定的同位素标记技术，评估了大型无脊椎动物对土壤团聚体丰度和组成的影响，并量化了源自根的有机物的命运。我们假设大型无脊椎动物通过增加大型聚集体和减少小型聚集体以及增强根系有机质到大型聚集体中的结合来改变土壤聚集体的动力学。我们发现在草皮草根区域内，大型无脊椎动物增加了大型聚集体的比例，减少了游离微聚集体。此外，大型无脊椎动物增加了碳和氮在大型集料，微集料和粗颗粒有机物中的结合，通过这些土壤部分的同位素富集检测。我们发现，大型无脊椎动物影响草皮草坪生态系统中最近固定的根和根茎固定有机物的命运，特别是将其掺入土壤团聚体中，这与森林和农业系统中的发现类似。