Biogas is an important energy source produced by the anaerobic fermentation of raw faecal slurries and plant residues. Separation of the total digestate increases the fertilizer quality of the liquid fraction and the carbon sequestration potential of the solid fraction. A 12-day incubation study was carried out to investigate the relationships between the chemical composition of different digestate qualities and the immediate response of soil microbial activity and biomass indices. The highest cumulative (Σ) CO2-C efflux was observed after adding the solid fraction and lowest after adding the liquid fraction to soil, which was even lower than that of the control. The ΣCO2-C efflux showed the strongest negative correlation with the raw ash and strong positive correlations with the raw fibre concentration and the C/N ratio of the different digestate qualities. The highest and similar ΣN2O-N efflux was observed after adding the total digestate or the liquid fraction, which were equivalent to approximately 1% of added N. This relatively low percentage indicates a possible origin from nitrifier denitrification. Total digestate and its liquid fraction exhibited considerable net-N mineralisation rates, which could mainly be predicted by the C/N ratios of the different digestate qualities. Microbial biomass C did not respond to the application of any digestate quality, whereas the fungal ergosterol content increased after applying the solid and the composted solid fractions. This raw fibre–induced fungal growth led to strong net-N immobilisation in soil after applying these two digestate qualities.

中文翻译：

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应用于土壤后直接矿化不同质量的沼气消化物

沼气是一种重要的能源，通过对未加工的粪便浆液和植物残渣进行厌氧发酵而产生。总消化物的分离提高了液体部分的肥料质量和固体部分的固碳潜力。进行了为期 12 天的孵化研究，以研究不同消化物质量的化学成分与土壤微生物活动和生物量指数的即时响应之间的关系。在添加固体部分后观察到最高的累积 (Σ) CO2-C 流出量，在向土壤中添加液体部分后观察到最低，甚至低于对照。ΣCO2-C 流出量与原灰分呈最强负相关，与原纤维浓度和不同消化液质量的 C/N 比呈强正相关。添加总消化物或液体部分后观察到最高且相似的 ΣN2O-N 流出量，相当于添加的 N 的约 1%。这个相对较低的百分比表明可能来自硝化菌反硝化作用。总消化液及其液体部分表现出相当大的净氮矿化率，这主要可以通过不同消化液质量的 C/N 比来预测。微生物生物质 C 不响应任何消化物质量的应用，而真菌麦角甾醇含量在应用固体和堆肥固体部分后增加。