Spatial variation in soil respiration rate is controlled by the content of particulate organic materials in the volcanic ash soil under a Cryptomeria japonica plantation
Spatial variation in soil respiration rate is controlled by the content of particulate organic materials in the volcanic ash soil under a Cryptomeria japonica plantation
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DOI：
10.1016/j.geodrs.2022.e00529
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发表时间：
2022-05-18
影响因子：
4.1
通讯作者：
Tange, Takeshi
中科院分区：
文献类型：
--
作者：
Abe, Yukiko;Liang, Naishen;Tange, Takeshi
土壤呼吸是全球碳循环中的主要碳通量之一，是理解全球碳平衡与气候变化关系的关键因素，但其空间变异的控制因素尚未得到很好的研究。本研究旨在探讨火山灰土壤呼吸速率空间变异的原因。2012年12月，我们在日本东京的一个35年生柳杉种植园建立了一个立木（ST）地块和一个皆伐（CC）地块。CC地块于2013年3月采伐，在皆伐后停止了新的有机质供应。2013年1月至2019年8月，分别在ST和CC样地的21个和19个测量点定期测量土壤呼吸速率。在ST小区（0.24公顷）和CC小区（0.23公顷）中，测量点以不同的距离随机分布。2019年8月，在所有测量点测量了0-5、5-15和15-30 cm矿物土层的凋落物（Ao）层碳含量、土壤总碳含量、土壤低密度部分（LF-C; < 1.6 g cm-3）碳含量、细根生物量和土壤容重。在整个7年的研究期间，土壤呼吸速率的变化的空间格局保持稳定的ST图。ST图中的多元回归分析结果表明，只有LF-C作为解释变量的模型具有最高的预测能力，在土壤温度为20摄氏度（R20）的呼吸速率;添加其他因素作为解释变量并没有增加预测能力。土壤有机碳含量与R20无相关性。在CC情节的R20显着减少后6年皆伐后的第一年相比，皆伐后，值分别为3.03和1.86 μ mol CO2 m-2 s-1。在2013年R20较高的测量点，这一下降趋势更大。皆伐后第7年CC样地0-30 cm土层的LF-C储量为0.33 kgCm-2，远低于ST样地的1.60 kgCm-2。这些结果进一步支持了LF-C是ST样地土壤呼吸速率空间变异的主要因子的结论，表明LF-C比SOC更适合作为火山灰土壤呼吸速率空间变异的解释变量。
Soil respiration is one of the major C fluxes in the global C cycle and is a key factor in understanding the global C balance associated with climate change, but the factors controlling its spatial variability have not been well explored. This study aimed to clarify the causes of spatial variation in soil respiration rate on volcanic ash soil. We established a standing-tree (ST) plot and a clear-cutting (CC) plot in December 2012 at a 35-year-old Cryptomeria japonica plantation in Tokyo, Japan. CC plot was logged in March 2013, and new organic matter supply was halted after clear-cutting. From January 2013 to August 2019, soil respiration rates were measured periodically at 21 and 19 measuring points in ST and CC plots, respectively. The measuring points were randomly distributed with varying distances in ST plot (0.24 ha) and CC plot (0.23 ha). In August 2019, the carbon content of the litter (Ao) layer, total carbon content of soil, carbon content of the low-density fraction (LF-C; < 1.6 g cm-3) of soil, fine root biomass, and bulk density of soil for 0-5, 5-15, and 15-30 cm mineral soil layers were measured at all measuring points. The spatial pattern of the variation in soil respiration rates remained stable in the ST plot throughout the 7-year study period. Results of the multiple regression analysis in the ST plot showed that the model with only the LF-C as an explanatory variable had the highest capability for predicting the respiration rate at a soil temperature of 20 degrees C (R20); the addition of other factors as explanatory variables did not increase the predictive capability. The organic carbon content in soil did not correlate with R20. The R20 in the CC plot significantly decreased six years after clear-cutting compared with the first year after clear-cutting, with values of 3.03 and 1.86 mu mol CO2 m-2 s-1, respectively. This decrease tended to be greater in the measuring points where R20 was high in 2013. The LF-C stock for 0-30 cm soil layer in CC plot in the 7th year after clearcutting was 0.33 kgC m-2 which was much lower than 1.60 kgC m-2 in ST plot. These results further support the conclusion that LF-C was the main factor responsible for the spatial variation in soil respiration rate in the ST plot, and suggest that LF-C is more suitable than SOC as an explanatory variable for the spatial variation in soil respiration rate in volcanic ash soil.