Incomplete knowledge on the environmental factors linking litter decomposition and the formation of soil organic matter (SOM) hampers the sustainable management of soil as a carbon (C) sink. Here, we explored the effect of soil texture on the fate of C from decomposing litter (Indiangrass; Sorghastrum nutans (L.) Nash) and the concurrent formation of SOM in mineral soils of different textures (sand- and clay-rich) and forest floor material. We quantified the amount of litter C respired, C remaining in the litter, and litter C retained in the soil/forest floor in a 186-day incubation employing stable isotope analyses (¹³C). We complemented our isotopic approach with the extraction of microbial biomarkers from the litter and soils/forest floor material and spectroscopic studies into the compositional changes of the incubated materials.

We found that soil texture affected both the decomposition of litter and the retention of litter-derived C in the soil. The soil rich in clay provided conditions favorable for a more efficient microbial utilization of the litter material (high pH and high C use efficiency) as compared to the sand-rich soil and the forest floor. This resulted in lower amounts of litter C respired as CO₂ (25.0%, vs. 55.6 and 56.1% in clay vs. sand and forest floor material, respectively) and higher amounts of litter C retained in the clay-rich soil (12.6% vs. 3.5 and 5.3% in clay vs. sand and forest floor material, respectively). High contents of silt- and clay-sized mineral particles in the clay-rich soil likely resulted in the ability to stabilize litter C in aggregates and organo-mineral associations, perhaps as microbial residues. This ability was low in the sand-rich soil and virtually absent in the forest floor, where the recalcitrance of the litter and native SOM was probably more relevant, and a larger portion of litter C may have been retained in the soil as relatively untransformed plant compounds. We emphasize that litter decomposition, the formation of SOM, and soil texture are tightly linked, such that any differences in soil texture alter litter decomposition and SOM formation patterns for the same litter.

对将凋落物分解和土壤有机质（SOM）形成联系的环境因素的不完整知识妨碍了土壤作为碳（C）汇的可持续管理。在这里，我们探讨了土壤质地对分解凋落物（印度洋草；高粱，高粱）以及土壤中不同质地（富含沙土和粘土的矿物土壤）和土壤有机质同时形成的命运的影响。地板材料。在使用稳定同位素分析进行​​的186天孵化中，我们量化了呼吸的凋落物C的数量，残留在凋落物中的C和残留在土壤/林地中的凋落物C的量（¹³C）。我们通过从垫料和土壤/林地材料中提取微生物生物标志物以及通过光谱研究研究孵化材料的成分变化，来补充同位素方法。

我们发现土壤质地既影响凋落物的分解，又影响凋落物衍生的碳在土壤中的保留。与富含沙子的土壤和林地相比，富含粘土的土壤为更有效地利用垃圾材料提供了有利的条件（高pH和高碳利用效率）。这样就减少了作为CO ₂呼吸的凋落物C的量。（分别为25.0％，分别为55.6％和56.1％的粘土，沙子和森林地面材料）和富含粘土的土壤中残留的凋落物C的数量较高（分别为12.6％，3.5％和5.3％，分别为粘土和沙子和木地板）。森林地板材料）。在富含粘土的土壤中，高含量的粉尘和粘土大小的矿物颗粒可能导致稳定碎屑C的聚集体和有机矿物质联合体（可能是微生物残留物）的能力。在富含沙子的土壤中这种能力很低，而在森林地面上几乎没有这种能力，在此凋落物和原生SOM的顽固性可能更相关，并且大部分的凋落物C可能作为相对未转化的植物保留在土壤中化合物。我们强调凋落物分解，SOM的形成和土壤质地密切相关，