Stability of pyrochar and hydrochar in agricultural soil - a new field incubation method
Stability of pyrochar and hydrochar in agricultural soil - a new field incubation method
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DOI：
10.1016/j.geoderma.2016.08.019
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发表时间：
2016-12-15
期刊：
影响因子：
6.1
通讯作者：
Don, Axel
中科院分区：
文献类型：
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作者：
Gronwald, Marco;Vos, Cora;Don, Axel
在土壤上施用炭提供了一种固碳（C）和提高土壤肥力的选择。不同类型的炭可用作土壤改良剂，主要由两种不同的过程产生：热解产生的焦和水热碳化产生的水热炭。然而，很少有研究，以评估这两种类型的焦炭在土壤中的稳定性在现场网站。在北方德国进行了为期19个月的现场培养。与迷你图的方法，我们能够评估的分解动力学的焦炭，很少的运营成本。锌被用作惰性示踪剂与炭混合，以考虑混合，使炭损失可以准确地量化。我们使用来自芒草（C4植物）的炭作为原料，其具有比C3植物来源的土壤C更高的δ 13 C值。δ 13 C值的变化允许在三个采样日期的土壤中的碳衍生的C的计算。虽然来自焦炭的C没有随着时间的推移而发生显着变化，但在19个月的原位现场培养后，23-30%的初始添加的水炭-C被矿化。不同土壤类型的3个样地，半焦的分解动态没有差异。此外，我们没有观察到分解率随时间的下降。对于水热炭，数据与线性单池衰减模型拟合良好。水热炭的平均停留时间为4年（95%置信区间：3-14），焦炭的平均停留时间为60年（95%置信区间：16-224）。因此，虽然焦炭具有更高的碳螯合潜力，但与焦炭相比，水热炭的矿化速度更快，表明它们有潜力通过缓慢的养分释放到土壤中来充当中期肥料。锌法的优点是应用和分析的价格低，以及农民在正常活动过程中管理田地的能力。然而，从锌方法获得的结果的变异性并不显著，这主要影响计算的MRT。(C)2016爱思唯尔B. V.保留所有权利。
The application of chars on soil offers an option to sequester carbon (C) and to improve soil fertility. Different types of chars are available as soil amendments, produced with mainly two different processes: pyrochar produced with pyrolysis and hydrochar produced with hydrothermal carbonization. However, there are few studies to assess the stability of these two char types in soils in situ at field sites. A 19-month in-situ field incubation was conducted in northern Germany. With a mini-plot method we were able to assess the decomposition dynamic of chars with few operational costs. Zinc was used as inert tracer mixed with the char in order to account mixing so that char losses could be accurately quantified. We used chars from Miscanthus (C4-plant) as feedstock with a higher delta 13C value than the C3 plant derived soil C. Changes in delta 13C value allowed the calculations of char-derived C in the soil at three sampling dates. While C derived from pyrochar did not change significantly over time, 23-30% of initial added hydrochar-C was mineralized after 19 months in-situ field incubation. There was no difference in the decomposition dynamics of the chars among the three field sites with different soil types. Moreover, we did not observe a decline in decomposition rates with time. For hydrochar the data were well fitted with a linear one-pool decay model. The average model derived mean residence times were 4 (95% confidence interval: 3-14) years for hydrochar and 60 (95% confidence interval: 16-224) years for pyrochar. Thus, while pyrochar has a higher potential for C-sequestration, faster mineralization of hydrochar compared to pyrochar showed their potential to act as a mid-term fertilizer through slow nutrient release to soils. Advantages of the Zinc method were the low price for application and analysis as well as the ability for farmers to manage their field in the course of their normal activities. However, variability in results gained from the Zinc method is not insignificant which mostly affect the calculated MRTs. (C) 2016 Elsevier B.V. All rights reserved.