Abstract

We assessed the soil carbon sequestration potential of various organic amendments of agricultural, municipal and industrial origin and the applicability of a soil carbon model to simulate it. The chemical composition of a large number of plant residues, manures, composts, digestates and biochars was determined and selected materials were incubated in soil to assess their decomposition rates and effects on soil microbial community structure. Decomposability was strongly correlated with the initial chemical composition determined by water, ethanol and acid extraction. Fresh plant materials decomposed the fastest, roots decomposed more slowly than aboveground biomass and processing decreased the decomposability of the materials. Soil carbon model Yasso07 predicted the decomposition of the amendments relatively well, except for fresh plant litter and fiber sludge from the pulp and paper industry which decomposed considerably faster than predicted by the model. Differences in the studied materials were also reflected in the soil microbial and fungal community composition. Plant root addition to laboratory microcosms induced a different soil microbial community compared to organic materials originating from the forest industry. Typical application rates of the studied amendments result in carbon sequestration at a rate sufficient to reach the goal of the 4/1000 initiative. The results can be used to select the most efficient measures to sequester carbon in croplands and to report the effects of practices like cover crop cultivation or organic matter addition.

摘要

我们评估了农业、市政和工业来源的各种有机改良剂的土壤固碳潜力以及土壤碳模型对其进行模拟的适用性。确定了大量植物残留物、粪便、堆肥、消化物和生物炭的化学成分，并将选定的材料在土壤中培养，以评估它们的分解速率和对土壤微生物群落结构的影响。可分解性与由水、乙醇和酸提取确定的初始化学成分密切相关。新鲜植物材料分解最快，根比地上生物量分解更慢，加工降低了材料的可分解性。土壤碳模型 Yasso07 较好地预测了修正物的分解，除了来自纸浆和造纸工业的新鲜植物垃圾和纤维污泥，它们的分解速度比模型预测的要快得多。研究材料的差异也反映在土壤微生物和真菌群落组成上。与源自森林工业的有机材料相比，将植物根添加到实验室微观世界中诱导了不同的土壤微生物群落。研究修正的典型应用率导致碳封存率足以达到 4/1000 倡议的目标。结果可用于选择最有效的措施来封存农田中的碳，并报告覆盖作物种植或添加有机物质等实践的影响。