Biochar production and application as soil amendment is a promising carbon (C)-negative technology to increase soil C sequestration and mitigate climate change. However, there is a lack of knowledge about biochar degradation rate in soil and its effects on native soil organic carbon (SOC), mainly due to the absence of long-term experiments performed in field conditions. The aim of this work was to investigate the long-term degradation rate of biochar in an 8-year field experiment in a poplar short-rotation coppice plantation in Piedmont (Italy), and to modify the RothC model to assess and predict how biochar influences soil C dynamics. The RothC model was modified by including two biochar pools, labile (4 % of the total biochar mass) and recalcitrant (96 %), and the priming effect of biochar on SOC. The model was calibrated and validated using data from the field experiment. The results confirm that biochar degradation can be faster in field conditions in comparison to laboratory experiments; nevertheless, it can contribute to a substantial increase in the soil C stock in the long term. Moreover, this study shows that the modified RothC model was able to simulate the dynamics of biochar and SOC degradation in soils in field conditions in the long term, at least in the specific conditions examined.

中文翻译：

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基于 8 年现场实验的观察结果，将 biochar 纳入 C 动力学模型

生物炭作为土壤改良剂的生产和应用是一种有前途的碳 (C) 负技术，可增加土壤固碳和缓解气候变化。然而，缺乏关于土壤中生物炭降解率及其对天然土壤有机碳（SOC）影响的知识，主要是由于缺乏在田间条件下进行的长期实验。这项工作的目的是研究在皮埃蒙特（意大利）的杨树短轮伐林地进行的为期 8 年的田间试验中生物炭的长期降解率，并修改 RothC 模型以评估和预测生物炭如何影响土壤 C 动力学。RothC 模型经过修改，包括两个生物炭池，不稳定的（总生物炭质量的 4%）和顽固的（96%），以及生物炭对 SOC 的启动作用。该模型使用来自现场实验的数据进行校准和验证。结果证实，与实验室实验相比，生物炭在田间条件下的降解速度更快；然而，从长远来看，它可以促进土壤碳储量的大幅增加。此外，这项研究表明，修改后的 RothC 模型能够长期模拟田间条件下土壤中生物炭和 SOC 降解的动态，至少在所检查的特定条件下是这样。