Degradation of Miscanthus x giganteus biochar, hydrochar and feedstock under the influence of disturbance events

作者：Schimmelpfennig Sonja^*; Kammann Claudia; Murnme Jan; Marhan Sven; Bamminger Chris; Moser Gerald; Mueller Christoph

来源：Applied Soil Ecology, 2017, 113: 135-150.

DOI：10.1016/j.apsoil.2017.01.006

• Biochar
• Hydrochar
• Degradation
• Greenhouse gases
• SOC mineralization
• Miscanthus x giganteus

Little is known about the degradation and environmental impacts of carbon (C) amendments such as hydrochar and biochar in soil under the influence of disturbance events such as wetting, freeze-thaw cycles, manual stirring, and glucose additions. Thus, we assessed the degradation and greenhouse gas (GHG) emissions of Miscanthus x giganteus biochar (from pyrolysis), hydrochar (from steam and water hydrothermal carbonization, HTCs and HTCw), the uncarbonized feedstock material in a sandy and a loamy soil, compared to a control, with four replicates per treatment. The C amendments were mixed with soil at a rate of similar to 20 t/ha wt% and incubated at 30 degrees C over the period of 441 days. Over the whole incubation period, the soil mixtures were exposed consecutively to different disturbance events, with the intention to simulate a worst-case scenario for C degradation and GHG emissions. The degradation kinetics were quantified by source partitioning of the headspace C-13-CO2 and the application of an isotope two-component mixing model. Additionally, microbial biomass and composition were quantified and characterized at the end of the experimental period by chloroform fumigation extraction and phospholipid fatty acid analysis. The molecular composition and structural properties of the C amendments obtained by elemental analysis and NMR spectroscopy proved to be suitable indicators for the CO2 emissions which mostly followed the sequence feedstock > HTCs > HTCw > biochar over the experimental duration. The addition of glucose triggered a short-lived, temporary co-mineralization of the otherwise recalcitrant materials HTCw and biochar. Among all C amendments, biochar proved most recalcitrant against decomposition and disturbance in both soils with a calculated recovery rate of 95-99% of the initially added biochar-C. Additionally, biochar amendment led to a decreased decomposition of soil organic C, especially in sandy soil.

• 出版日期2017-5