Lower microbial carbon use efficiency reduces cellulose-derived carbon retention in soils amended with compost versus mineral fertilizers

作者：Yuncai Miao, Yuhui Niu, Ruyi Luo, Ye Li, Huijie Zheng, Yakov Kuzyakov, Zengming Chen, Deyan Liu, Weixin Ding · 发表于：Soil Biology and Biochemistry · 年份：2021 · DOI：10.1016/j.soilbio.2021.108227 · 被引用次数：41 · 研究领域：Soil Carbon and Nitrogen Dynamics、Plant nutrient uptake and metabolism、Clay minerals and soil interactions

Cellulose decomposition is a key process in soil carbon (C) cycling due to the high abundance of cellulose in plant biomass. Microbial functional groups that sequester C from cellulose, and the accumulation of cellulose C in soil aggregates, remains debated. We hypothesized that cellulose derived 13C would be more efficiently converted into soil organic C by microorganisms, and retained in soil subjected to long-term application of compost. In this study, soil sampled from a long-term (27 years) field experiment with application of compost (Compost), NPK fertilizers (NPK) and without fertilizers (control), was incubated with 13C-cellulose for 120 days. The cellulose 13C content, microbial community structure (lipid biomarkers) and microbial 13C use efficiency (CUE) were measured. The incorporation of 13C into large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm), microaggregates (53–250 μm), and silt + clay fraction (<53 μm) was analyzed to elucidate cellulose 13C sequestration process in aggregates. In contrast to our initial hypothesis, 13C remaining in soil after 120 days of incubation was maximal in unfertilized soil (25%) and minimal in Compost soil (17%). Compost soil had higher abundance of fungi and especially fast-growing bacteria (Gram-negative (G–) bacteria) than NPK and control soils. This accelerated decomposition and lowered CUE of 13C, therefore reducing the amount of 13C remaining in the Compost soil. In contrast, in the other soils, the lower ...