ABSTRACT

Organic matter (OM) application is a possible solution to carbon (C) sequestration. Among the soil pedogenic factors for volcanic ash, time of exposure to weathering affects formation of short-range ordered minerals and soil organic carbon (SOC) accumulation. This study aimed to evaluate the effect of long-term OM application with the vertical infiltration of OM on different ages of Andosols in Hokkaido, Japan. Twelve fields of Vitric Andosols and 22 fields of Silandic Andosols were selected. Vitric and Silandic Andosols are characterized by newly erupted volcanic ash with weak weathering, and formation of short-range ordered minerals by weathering, respectively. The C application rate via OM was determined using questionnaires given to farmers, and soil physicochemical properties in the 0–0.15 m and 0.15–0.30 m layers were analyzed.

The average C application rate in Vitric and Silandic Andosols were 1.71 ± 1.18 and 1.31 ± 1.28 (Mg C ha⁻¹ yr⁻¹), respectively (mean ± sd). The sand content was significantly higher in Vitric Andosols (55.7% ± 4.0%) than in Silandic Andosol (51.2% ± 2.0%). Although there was no significant difference in micro-porosity, Silandic Andosols had significantly higher total porosity and lower bulk density than Vitric Andosols. These results indicate better soil structure development in Silandic Andosols. The SOC stock in the 0–0.30 m layer in Vitric Andosols [71.5 ± 15.3 (Mg C ha⁻¹ 0.30 m⁻¹)] was significantly lower than in Silandic Andosols [86.4 ± 12.7 (Mg C ha⁻¹ 0.30 m⁻¹)]. The SOC stock in Vitric and Silandic Andosols showed a different response to the OM application. An increased C application rate significantly increased the SOC stock in the 0–0.15 and 0–0.30 m layers in Vitric Andosols, but the relations were not significant in Silandic Andosols. In contrast, in Silandic Adosols, weak trends (p = 0.07) were observed in the 0.15–0.30 m layer. In Silandic Andosols, SOC stock in the 0–0.15 m layer showed a z significant positive correlation with soil micro-porosity, suggesting physical protection of OM inside the aggregate. These results suggest that there are different factors affecting SOC stock between Vitric and Silandic Andosols.

摘要

有机物 (OM) 应用是碳 (C) 封存的可能解决方案。在火山灰的土壤成土因素中，暴露于风化的时间会影响短程有序矿物质的形成和土壤有机碳 (SOC) 的积累。本研究旨在评估长期施用有机肥和有机肥垂直渗透对日本北海道不同年龄的安多溶胶的影响。选择了12个Vitric Andosols领域和22个Silandic Andosols领域。Vitric and Silandic Andosols的特征分别是新喷发的火山灰，风化作用较弱，风化作用形成短程有序矿物。使用向农民提供的调查问卷确定通过有机肥施用的碳量，并分析了 0-0.15 m 和 0.15-0.30 m 层的土壤理化性质。

Vitric 和 Silandic Andosols 中的平均 C 施用率分别为 1.71 ± 1.18 和 1.31 ± 1.28 (Mg C ha ^-1 yr ^-1 )（平均值 ± sd）。Vitric Andosols (55.7% ± 4.0%) 的含砂量明显高于Silandic Andosol (51.2% ± 2.0%)。尽管微孔隙率没有显着差异，但 Silandic Andosols 的总孔隙率明显高于 Vitric Andosols，堆积密度更低。这些结果表明在 Silandic Andosols 中更好的土壤结构发展。Vitric Andosols [71.5 ± 15.3 (Mg C ha ^-1 0.30 m ^-1 )]中 0–0.30 m 层的 SOC 储量显着低于 Silandic Andosols [86.4 ± 12.7 (Mg C ha ^-1 0.30 m ^{-1 )})]。Vitric 和 Silandic Andosols 中的 SOC 储量对 OM 应用显示出不同的反应。在 Vitric Andosols 中，C 施用率的增加显着增加了 0-0.15 和 0-0.30 m 层的 SOC 储量，但在 Silandic Andosols 中这种关系不显着。相比之下，在 Silandic Adosols 中，在 0.15-0.30 m 层中观察到弱趋势 ( p = 0.07)。在 Silandic Andosols 中，0-0.15 m 层的 SOC 储量与土壤微孔隙度呈显着正相关，表明聚集体内部的 OM 受到物理保护。这些结果表明，在 Vitric 和 Silandic Andosols 之间存在影响 SOC 储量的不同因素。