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Abe, Yukiko; Nakayama, Masataka*; Atarashi-Andoh, Mariko; Tange, Takeshi*; Sawada, Haruo*; Liang, N.*; Koarashi, Jun
Geoderma, 455, p.117221_1 - 117221_11, 2025/03
Times Cited Count：0 Percentile：0.00(Soil Science)Subsoils (typically below a depth of 30 cm) contain more than half of global soil carbon (C) as soil organic C (SOC). However, the extent to which subsoil SOC contributes to the global C cycle and the factors that control it are unclear because quantitative evaluation of carbon dioxide (CO
) emission from subsoils through direct observations is limited. This study aimed to quantify CO emission from subsoils and determine factors that control CO emission, focusing on the decomposability of soil organic matter (SOM) and the characteristics of the mineral-SOM association in soils. Therefore, a laboratory incubation experiment was conducted using surface soils (0-10 cm and 10-25 cm depth) and subsoils (30-45 cm and 45-60 cm depth) collected from four Japanese forest sites with two different soil types (volcanic ash and non-volcanic ash soils). The CO emission from the subsoils was found to be responsible for 6%-23% of total CO emission from the upper 60-cm mineral soil across all sites. Radiocarbon signatures of CO released from the subsoils indicated the decomposition of decades-old SOM in the subsoils. The correlations between CO emission rate and soil factors across both soil types suggested that the CO emission from the subsoils is mainly controlled by the amounts of SOC easily available to soil microbes and microbial biomass C, not by the amounts of reactive minerals. Given the potential active participation of subsoils in terrestrial C cycling, most of the current soil C models that ignore subsoil C cycling are likely to underestimate the response of soil C to future climate change. The quantitative and mechanistic understanding of C cycling through a huge subsoil C pool is critical to accurately evaluating the role of soil C in the global C balance.
Nakayama, Masataka; Abe, Yukiko; Atarashi-Andoh, Mariko; Tange, Takeshi*; Sawada, Haruo*; Liang, N.*; Koarashi, Jun
Applied Soil Ecology, 201, p.105485_1 - 105485_12, 2024/09
Times Cited Count：4 Percentile：74.70(Soil Science)Nitrogen often limits plant growth in forest ecosystems. Plants, including trees, change vertical root distribution when nutrient competition is strong within surface soil layer and take up nitrogen even from subsurface soil layers in addition to the surface soil. However, there is still limited knowledge about nitrogen cycles within deeper soil layers. In this study, we investigated the vertical profiles (0-60 cm) of the net nitrogen mineralization and nitrification rates at four Japanese forest sites with two different soil types (Andosols and Cambisols). The partial least square path modeling (PLS-PM) was used to determine factors affecting nitrogen-cycling processes. The net nitrogen mineralization and nitrification rates per unit soil weight were considerably higher in surface soil layer than in deeper soil layers in Andosols but not in Cambisols. PLS-PM analysis showed that microbial biomass and soil organic matter quantities were the main factors influencing the net nitrogen mineralization and nitrification rates, indicating that a similar mechanism creating the spatial variations of nitrogen-cycling processes in surface soil layer predominantly regulates the processes in subsoil layers. Moreover, it was estimated that the net nitrogen mineralization rate could be comparable at all soil types and depths when the rate was expressed per unit soil volume. Therefore, our results suggest that subsoil layers are a quantitatively important nitrogen source for plant nutrients in Andosols and Cambisols, supporting high forest productivity.
Be ground-state molecular structure using Be(
)
He triple differential reaction cross-section measurementsLi, P. J.*; Beaumel, D.*; Lee, J.*; Assi
, M.*; Chen, S.*; Franchoo, S.*; Gibelin, J.*; Hammache, F.*; Harada, T.*; Kanada-En'yo, Yoshiko*; et al.
Physical Review Letters, 131(21), p.212501_1 - 212501_7, 2023/11
Times Cited Count：25 Percentile：94.13(Physics, Multidisciplinary)The cluster structure of the neutron-rich isotope Be has been probed via the () reaction. The triple differential cross-section was extracted and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using the Tohsaki-Horiuchi-Schuck-R
pke wave function and the wave function deduced from Antisymmetrized Molecular Dynamics calculations. The remarkable agreement between calculated and measured cross-sections in both shape and magnitude validates the description of the Be ground-state as a rather compact nuclear molecule.
100 MeV/nucleonPohl, T.*; Sun, Y. L.*; Obertelli, A.*; Lee, J.*; G
mez-Ramos, M.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Cai, B. S.*; Yuan, C. X.*; Brown, B. A.*; et al.
Physical Review Letters, 130(17), p.172501_1 - 172501_8, 2023/04
Times Cited Count：15 Percentile：88.36(Physics, Multidisciplinary)We report on the first proton-induced single proton- and neutron-removal reactions from the neutron deficient 
O nucleus with large Fermi-surface asymmetry at 100 MeV/nucleon. Our results provide the first quantitative contributions of multiple reaction mechanisms including the quasifree knockout, inelastic scattering, and nucleon transfer processes. It is shown that the inelastic scattering and nucleon transfer, usually neglected at such energy regime, contribute about 50% and 30% to the loosely bound proton and deeply bound neutron removal, respectively.
Zhang, J.*; Kuang, L.*; Mou, Z.*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko; Li, Y.*; Tang, X.*; Wang, Y.-P.*; Pe
uelas, J.*; et al.
Plant and Soil, 481(1-2), p.349 - 365, 2022/12
Times Cited Count：13 Percentile：78.21(Agronomy)
plantationAbe, Yukiko*; Liang, N.*; Teramoto, Munemasa*; Koarashi, Jun; Atarashi-Andoh, Mariko; Hashimoto, Shoji*; Tange, Takeshi*
Geoderma Regional (Internet), 29, p.e00529_1 - e00529_11, 2022/06
Times Cited Count：4 Percentile：26.01(Soil Science)This study aimed to clarify the causes of spatial variation in soil respiration rate on volcanic ash soil. From January 2013 to August 2019, soil respiration rates were measured at 40 measuring points periodically at a 35-year-old plantation in Tokyo, Japan. In August 2019, the carbon content of the litter layer, total carbon content of soil organic matter (SOM), carbon content of the low-density fraction (LF-C) of SOM, fine root biomass, and bulk density of soil were measured at all measuring points. Results of the multiple regression analysis 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
C, indicating that LF-C, which is considered to be readily available to soil microorganisms, can be the main factor responsible for the spatial variation in soil respiration rate.
Koarashi, Jun; Atarashi-Andoh, Mariko; Nagano, Hirohiko*; Sugiharto, U.*; Saengkorakot, C.*; Suzuki, Takashi; Kokubu, Yoko; Fujita, Natsuko; Kinoshita, Naoki; Nagai, Haruyasu; et al.
JAEA-Technology 2020-012, 53 Pages, 2020/10
JAEA-Technology-2020-012.pdf:3.71MB
There is growing concern that recent rapid changes in climate and environment could have a significant influence on carbon cycling in terrestrial ecosystems (especially forest ecosystems) and could consequently lead to a positive feedback for global warming. The magnitude and timing of this feedback remain highly uncertain largely due to a lack of quantitative understanding of the dynamics of organic carbon stored in soils and its responses to changes in climate and environment. The tracing of radiocarbon (natural and bomb-derived C) and stable carbon (
C) isotopes through terrestrial ecosystems can be a powerful tool for studying soil organic carbon (SOC) dynamics. The primary aim of this guide is to promote the use of isotope-based approaches to improve our understanding of the carbon cycling in soils, particularly in the Asian region. The guide covers practical methods of soil sampling; treatment and fractionation of soil samples; preparation of soil samples for C (and stable nitrogen isotope, 
N) and C analyses; and C, N, and C measurements by the use of isotope ratio mass spectrometry and accelerator mass spectrometry (AMS). The guide briefly introduces ways to report C data, which are frequently used for soil carbon cycling studies. The guide also reports results of a case study conducted in a Japanese forest ecosystem, as a practical application of the use of isotope-based approaches. This guide is mainly intended for researchers who are interested but are not experienced in this research field. The guide will hopefully encourage readers to participate in soil carbon cycling studies, including field works, laboratory experiments, isotope analyses, and discussions with great interest.
Teramoto, Munemasa*; Kondo, Toshiaki*; Liang, N.*; Zeng, J.*; Nakane, Kaneyuki*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
Kondo, Toshiaki*; Teramoto, Munemasa*; Nakane, Kaneyuki*; Takagi, Kentaro*; Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Masahiro*; Ishida, Sachinobu*; Liang, N.*
no journal, ,
Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Kentaro*; Kondo, Toshiaki*; Teramoto, Munemasa*; Nagano, Hirohiko; Kokubu, Yoko; Takagi, Masahiro*; Ishida, Sachinobu*; Hiradate, Shuntaro*; et al.
no journal, ,
no abstracts in English
Teramoto, Munemasa*; Liang, N.*; Jiye, Z.*; Koarashi, Jun; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Aramaki, Takafumi*; Zhao, X.*
no journal, ,
Forest soils are a large source for CO and sink for CH
. Understanding long-term response of these soil carbon fluxes to warmer environment is the key to mitigation and adaptation for future climate change. To examine the long-term response of CO flux to global warming in Asian monsoon forests, we set multi-channel automated chamber measurement system in a red pine forest in Tsukuba. Half of the chambers were artificially warmed by infrared heaters. Recently, we started continuous measurement of soil CH flux using a control unit with CH analyzer. Results showed that soil temperature is the primary factor controlling soil CO fluxes, whereas soil moisture is the main factor controlling soil CH uptake in our study site.
Abe, Yukiko*; Liang, N.*; Koarashi, Jun; Atarashi-Andoh, Mariko; Teramoto, Munemasa*; Hashimoto, Shoji*; Tange, Takeshi*
no journal, ,
We measured soil respiration rates (SR) at 21 points in a Cryptomeria japonica plantation of Tokyo University of Agriculture Okutama Forest, from January 2013 to August 2019, and examined temporal changes and factors of spatial variation. The observation showed that the measured points with higher SR in 2013 tended to have higher SR throughout the seven years. There was not significant correlation between the amount of organic carbon in the surface soil and SR. However, the amount of light fraction (
1.6 g cm
) of soil or fine root biomass in the surface soil had a significant positive correlation with SR. Since the light fraction of soil contains organic matter that is easily decomposed by microbes, the variation of the easily decomposable organic matter content was considered to be the cause of the spatial variation in SR.
Kondo, Toshiaki*; Teramoto, Munemasa*; Takagi, Kentaro*; Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Masahiro*; Ishida, Sachinobu*; Liang, N.*
no journal, ,
no abstracts in English
Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Kentaro*; Kondo, Toshiaki*; Teramoto, Munemasa*; Nagano, Hirohiko*; Kokubu, Yoko; Takagi, Masahiro*; Ishida, Sachinobu*; Ichii, Kazuhito*; et al.
no journal, ,
no abstracts in English
Teramoto, Munemasa*; Liang, N.*; Takagi, Kentaro*; Kondo, Toshiaki*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Masahiro*; Ishida, Sachinobu*; Naramoto, Masaaki*; et al.
no journal, ,
Takagi, Kentaro*; Liang, N.*; Aguilos, M.*; Teramoto, Munemasa*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
Koarashi, Jun; Atarashi-Andoh, Mariko; Takagi, Kentaro*; Kondo, Toshiaki*; Teramoto, Munemasa*; Nagano, Hirohiko; Kokubu, Yoko; Takagi, Masahiro*; Ishida, Sachinobu*; Hiradate, Shuntaro*; et al.
no journal, ,
no abstracts in English
Teramoto, Munemasa*; Kondo, Toshiaki*; Liang, N.*; Zeng, J.*; Nakane, Kaneyuki*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
Takagi, Kentaro*; Liang, N.*; Aguilos, M.*; Kira, R.*; Teramoto, Munemasa*; Kobayashi, Makoto*; Sun, L.*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko
no journal, ,
no abstracts in English
Liang, N.*; Takahashi, Yoshiyuki*; Teramoto, Munemasa*; Zhao, X.*; Tomimatsu, Hajime*; Takagi, Kentaro*; Hirano, Takashi*; Kondo, Toshiaki*; Koarashi, Jun; Atarashi-Andoh, Mariko; et al.
no journal, ,
no abstracts in English
