MIS03-P01

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

Applications of Cavity Ring-Down Spectroscopy to carbon, nitrogen and water cycling insoil
Applications of Cavity Ring-Down Spectroscopy to carbon, nitrogen and water cycling in
soil
DENNIS, Kate1∗ ; HUANG, Kuan1
DENNIS, Kate1∗ ; HUANG, Kuan1
1
1

Picarro, Inc.
Picarro, Inc.

Over the past five years, advances in cavity-enhanced absorption spectroscopy have fundamentally changed the way soil
scientists study carbon, nitrogen and water cycling between the subsurface, plants and the atmosphere. With the continuous
evolution of performance, including high precision, low drift and part-per-billion resolution, along with compact, field-deployableand easy-to-use instruments, scientists are increasingly able to leave their labs and make measurements directly in the field.
Here we describe how Picarro’s Cavity Ring-Down Spectroscopy technology has been applied to a number of soil applications,
including (i) the determination of soil flux measurements by coupling newly developed real-time software with simultaneous
measurements of CO2 , CH4 , N2 O, NH3 and H2 O from closed-loop, recirculated soil chambers; (ii) partitioning water loss
from evaporation versus transpiration in arid environments using in-situ measurements of ambient atmospheric water vapor
measurements, soil water isotopes and the isotopic signature of local transpiration; and (iii) using in-situ measurements of d15 N
and the site preference of 15 N in N2 O to constrain N2 O emissions in agricultural settings.
キーワード: CRDS, soil flux, nitrogen isotopes, evapotranspiration
Keywords: CRDS, soil flux, nitrogen isotopes, evapotranspiration

1/1

MIS03-P02

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

土壌中の有機炭素と熱・水ダイナミクスの間のフィードバックのシミュレーション
再現
The effect of the feedback cycle between the soil organic carbon and the soil hydrologic
and thermal dynamics
伊勢 武史 1∗ ; 森 健介 2
ISE, Takeshi1∗ ; MORI, Kensuke2
1
1

京都大学フィールド科学教育研究センター, 2 カルガリー大学
Field Science Education and Research Center, Kyoto University, 2 Department of Geomatics Engineering, University of Calgary

Biogeochemical feedback processes between soil organic carbon (SOC) in high-latitude organic soils and climate change isof great concern for projecting future climate. More accurate models of the SOC stock and its dynamics in organic soil are ofincreasing importance. As a first step toward creating a soil model that accurately represents SOC dynamics, we have createdthe Physical and Biogeochemical Soil Dynamics Model (PB-SDM) that couples a land surface model with a SOC dynamics
model to simulate the feedback cycle of SOC accumulation and thermal hydrological dynamics of high-latitude soils. The
model successfully simulated soil temperatures for observed data from a boreal forest near Fairbanks, and 2000 year simulations
indicated that the effect of the feedback cycle of SOC accumulation on soil thickness would result in a significant differences in
the amount of SOC.
Although it is still under development, the PB-SDM showed the significance of one of the feedback processes in high-latitudeorganic soil dynamics. Further develop- ment of the model has the potential to provide more in- sights into organic soil feedbacks
in response to climate change.
Keywords: biogeochemistry, peat, climate change, soil organic carbon, boreal forest

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MIS03-P03

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

陸域生態系における土壌微生物バイオマス炭素、窒素、リン組成比の全球スケール
でのパターン解析
Global patterns of soil microbial carbon, nitrogen and phosphorus stoichiometry in terrestrial ecosystems
朝田 景 1∗ ; 神田 隆志 2 ; 浅野 眞希 2 ; 江口 定夫 1
ASADA, Kei1∗ ; KANDA, Takashi2 ; ASANO, Maki2 ; EGUCHI, Sadao1
1

独立行政法人 農業環境技術研究所, 2 筑波大学 生命環境科学研究科
National Institute for Agro-Environmental Sciences, 2 The Graduate School Life and Environmental Sciences, University ofTsukuba1

Incorporating site-specific microbial processes may improve models of carbon (C) and nutrient cycling across terrestrial
ecosystems. To better understand the concentrations and stoichiometry of C, nitrogen (N) and phosphorus (P) in soil microbial biomass, we compiled and analyzed the existing published data on microbial C, N and P in soils spanning the global
range of land-use types (forest, grassland, paddy, upland and orchard) and soil types based on Harmonized World Soil Database(FAO/IIASA/ISRIC/ISSCAS/JRC, 2012). It was found that the microbial stoichiometry had some flexibility under various environmental conditions. Flooded paddy soil had the highest C:N ratio of soil microbes among the global land-use types while C:Pand N:P ratios highlighted the differences between forest and grassland, following upland field, and paddy or orchard fields. Agricultural soils (except paddy) had significantly lower C, N and P concentrations in soil microbial biomass than natural land-use,
indicating large anthropogenic effects (e.g., land management). The spatial patterns of microbial-C and nutrient ratios differedconsiderably among soil types. For global microbial C:N ratio, the geometric mean varied from maximum 12.7 for Phaeozems tominimum 5.8 for Podzols. The microbial N:P ratio for Andosols was significantly higher than other soils. The consistency of thispattern in plant-soil-microbe ecosystems supports that P is often the major limiting element for Andosols. Meanwhile, higher
concentrations of microbial-N and P may relate to high soil water contents, i.e., low permeability soils of Gleysols and Fluvisols.
In this study, we provide more reliable parameters to determine soil microbial properties especially in agricultural land-use, i.e.,
Andosols mainly used for upland fields and Fluvisols used for paddy fields, as there are no existing data available.
Keywords: Andosols, Harmonized World Soil Database, Land-use, Global scale analysis, Terrestrial ecosystem, Paddy fields

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MIS03-P04

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

Decomposing global soil carbon projection uncertainties in ISI-MIP study
Decomposing global soil carbon projection uncertainties in ISI-MIP study
仁科 一哉 1∗ ; 伊藤 昭彦 1
NISHINA, Kazuya1∗ ; ITO, Akihiko1
1
1

国立環境研究所
National Institute for Environmental Studies

In earth system processes, because of the vast carbon pool of soil organic carbon (SOC), the behavior of SOC is the key tounderstanding the feedback of terrestrial ecosystems to atmospheric CO2 concentration in a warmer world. There seem to be
still large uncertainties in SOC projection. Therefore, how the uncertainties in SOC projection matters in future C projection
and which uncertainty sources cause SOC projection uncertainty should be clarified to reduce SOC projection uncertainties. In
this study, we performed simulations using six global vegetation models (GVM) using climate projections based on five climate
models (GCM) forced by four RCP-based atmospheric concentration scenarios, aiming at specifying the relative uncertainty inthe projection of global SOC stocks from global and regional perspectives.
At the end of the simulation period (2099), global 4net primary production ranged from -7.0 to 54.3 Pg-C Year−1 , global
4vegetation biomass C ranged from -27 to 543 Pg-C Year−1 , and global 4SOC ranged from -195 to 471 Pg-C Year−1 in theentire simulation set. Thus, SOC projection uncertainty was relatively large compared to above biomass changes. We conducted
ANOVA to the changes in NPP, VegC, and SOC as factors to be RCP, GCM, and GVM in global and regional scale, which enable
us to know relative importance of these factors to changes in C. For 4NPP, the GCM uncertainty dominated before the year
2020, and the RCP uncertainty increased and dominated after 2040. The GVM uncertainties were approximately 20% in mostof the simulation period. GVM dominate uncertainties (60% and 90%, respectively) rather than climate driving scenarios (i.e.,
GCM and RCP) in the global 4VegC, and 4SOC projections. In addition, we found that the contributions of each uncertainty
source were spatio-temporally heterogeneous and differed among the GVM variables (Fig. 1). These results indicated to improve
the SOC process in GVM is essential to reduce global C projection uncertainty. In the poster presentation, we will discuss about
the difference in SOC processes of GVM in detail.
Figure 1. Relative importance of each uncertainty source to 4NPP, 4VegC, and 4SOC (from Nishina et al., 2014 in ESDD)

1/1

MIS03-P05

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

ミクロネシア連邦ポンペイ島のサンゴ礁上マングローブ林における泥炭有機物の蓄積過程
Accumulation processes of organic carbon in peat deposit in a tropical mangrove forest
on Pohnpei Island, FSM.
小野 賢二 1∗ ; 平舘 俊太郎 2 ; 藤本 潔 3 ; 平田 泰雅 1 ; 平出 政和 1 ; 田淵 隆一 1 ; リパイ サイモン 4
ONO, Kenji1∗ ; HIRADATE, Syuntaro2 ; FUJIMOTO, Kiyoshi3 ; HIRATA, Yasumasa1 ; HIRAIDE, Masakazu1 ;TABUCHI, Ryuuichi1 ; LIHPAI, Saimon41

独立行政法人森林総合研究所, 2 独立行政法人農業環境技術研究所, 3 南山大学, 4 ポンペイ州政府 土地資源管理局
Forestry and Forest Products Research Institute, 2 National Institute for Agro-Environmental Sciences, 3 Nanzan University,
4
Department of Land and Natural Resources, Pohnpei State Government
1

To quantitatively evaluate organic carbon accumulation processes in peat deposits on a tropical mangrove ecosystems, solidstate 13 C cross-polarization and magic angle spinning nuclear magnetic resonance (CPMAS NMR) signals were monitored todetermine the organic carbon composition of humified leaf and root, which account for a large majority of mangrove-produced
litters and mangrove peat in a coral reef-type Rhizophora forest on Pohnpei Island, Federated States of Micronesia. Radiocarbon
dating was also used to estimate the average turnover times of peat deposits at each depth. The mass loss rate of mangrove leaves
during humification was much higher than that of roots. Mass loss rates of mangrove leaves and roots are expected to be affectedby their varying chemical characteristics and the different aerobic/hydrological conditions present in the two litter types during
humification processes. The decomposability of individual organic carbon components also varied markedly between leaf androot litters. Significant increases in aryl-C/O -alkyl-C and aliphatic-C/O -alkyl-C ratios and minor increases in aryl-C/aliphatic-C
ratio during the humification of leaves implied that only the O -alkyl-C component was relatively labile compared with aryl- andaliphatic-C, and that the decomposability of aliphatic-C was also slightly higher than that of aryl-C, while the difference was not
significant in leaf litters on the forest floor. Regarding roots, a stable aryl-C/O -alkyl-C ratio during humification suggests thatthe decomposability of aryl- and O -alkyl-C components did not differ greatly in the peat deposit, while the concomitant minor
increase in the aliphatic-/O -alkyl-C ratio and the substantial decrease in the aryl-/aliphatic-C ratio with humification imply that
aliphatic-C was more recalcitrant than aryl- and O -alkyl-C in the peat. Conversely, the compositional properties of organic carbon
and the ages of 14 C of the peat deposit were quite homogenous and relatively modern throughout the peat profile, suggesting thatlarge amount of mangrove roots penetrate up to at least 80-cm depth. These findings provide quantitative and qualitative insights
into the potential importance of very high production of mangrove fine roots for organic carbon accumulation in peat in tropicalmangrove ecosystems.
キーワード: 泥炭有機物, 14C 年代, サンゴ礁上マングローブ林, 固体 13C 核磁気共鳴法
Keywords: peat deposit, organic carbon, 14C dating, coral reef-type mangrove forest, solid-state 13C CPMAS NMR

1/1

MIS03-P06

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

ブラジル・パラ州トメアスーにおける異なる遷移過程のアグロフォレストリーにおける炭素循環
Carbon cycle at different succession stages of agroforestry in Tome-Acu, Para, Brazil
小畑 雄司 1 ; 木村 園子ドロテア 1∗ ; 山田 祐彰 1 ; イラエ アマラル 2 ; ウメムラ エリオ誠 1 ;ドスサントス ディナルド アントニオ 3
KOBATA, Yuji1 ; KIMURA, Sonoko dorothea1∗ ; YAMADA, Masaaki1 ; IRAE, Amaral g2 ;UMEMURA, Helio makoto1 ; DOS SANTOS, Dinaldo antonio3
1

東京農工大学院農学研究院, 2 サンパウロ州立大学ボツカツ校, 3 トメアスー総合農業共同組合
Tokyo University of Agriculture and Technology, Graduate School of Agriculture, 2 Sao Paulo State University, Botucatsu,
3
CAMTA

1

Introduction
In Tome-Acu, Para, Brazil, farmers plant crops to establish a series of successive harvests that is called Agroforestry System ofTome-Acu (SAFTA: Subler, 1993; Tanaka, 1997). Its sequence is similar to natural succession and farmers can use the fields fora long period (Subler and Uhl, 1990; Subler, 1993; Yamada and Gholz, 2002). Based on farmers experience, the mechanism of
SAFTA has not been well documented. Especially the change during the succession or the effect of the change on nutrients andcarbon (C) flow has not been documented. Thus, the objective of this study was to clarify the change in C flow during succession
and its mechanism to clarify the advantage of SAFTA.
MethodThree different succession stages were selected; since 2008 (6 years old; 6YO), since 2002 (12YO) and since 1980 (34YO).
The C flow was analyzed by measuring the C abundance in (1) aboveground biomass, (2) soil, (3) litter and (4) yield and (5) the
carbon dioxide (CO2 ) emission from soil. In addition to the agroforestry field, abundance of C in soil and litter as well as soil
respiration were monitored in a secondary forest. The measurement was conducted from September 2012 to July 2014. The C
balance was calculated by the difference of all input (aboveground biomass increase, litter and harvested yield) and output (soilrespiration and yield residue).
Result and Discussion
The increase of aboveground biomass of cocoa from 2013 to 2014 was 3.2 kg tree −1 in 6YO and significantly larger thanother stages (1.5 and 1.9 for 12YO and 34YO, respectively) The yield of cocoa was highest in 12YO and contained 3.3 kg-C
tree−1 . The yield in 6 and 34YO were almost same with 1.5-1.9 kg-C tree−1 . Litter was highest in secondary forest with 8.2
Mg C ha−1 year−1 . The litter of 6YO, 12YO and 34YO increased with the age, and were 4.6, 5.6 and 7.1 Mg C ha−1 year−1 ,respectively.
Soil carbon stock from 0 to 30 cm depth was 109.8 Mg ha−1 in secondary forest, those for 6YO, 12YO and 34YO were
57.4, 77.7 and 101.3 Mg ha−1 , respectively. There was no significant difference among them. But as the agroforestry stages
progressed, the amount of litter fall and soil carbon tended to increased.
Soil respiration rate in litter removed chamber (L-) in secondary forest was 129 mg CO2 -C m−2 h−1 , those for 6YO, 12YO
and 34YO were 81, 84 and 92 mg CO2 -C m−2 h−1 , respectively. Soil respiration rate in chamber with litter (L+) in secondary
forest was 176 mg CO2 -C m−2 h−1 , those for 6YO, 12YO and 34YO were 77, 104 and 113 mg CO2 -C m−2 h−1 , respectively.
The soil respiration rate in removed litter chamber was significantly lower than the chamber with litter in each site except 6YO.
The respiration is the sum of root respiration and soil organic matter decomposition. The high soil respiration rate in secondary
forest can be attributed to the litter fall as well as the high amount of roots.
Soil respiration rates in this study were similar to results reported for tropical forest in Brazil (59-139 mg CO2 -C m−2 h−1(Fernandes et al. 2002; Davidson et al. 2000), but lower than that of pasture in Brazil (117-317 mg CO2 -C m−2 h−1 (Fernandes
et al. 2002). It was suggested that carbon turnover in agroforestry is similar to forest and harder to decompose compared withherbaceous plant in pasture.
As a consequence, the C balance in 6YO, 12YO, 34YO were 4.1, 4.5, 3.9 ton C ha−1 year−1 , respectively.
Conclusion
Our results showed that the amount of litter fall and soil C increased as the agroforestry stages progressed, indicating a higher
internal nutrient cycling according to the Agroforestry age. All agroforestry stages in this study were found to be a C sink. The
applied fertilizer at the younger age will be stored in the aboveground plant parts, as well as in the soil.
1/2

MIS03-P06

会場:コンベンションホール

キーワード: 熱帯土壌, 土壌呼吸, 炭素循環, アグロフォレストリー
Keywords: Tropical soil, Soil respiratoin, Carbon cycle, Agroforestry

2/2

時間:5 月 27 日 18:15-19:30

MIS03-P07

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

微生物及び鉱物が土壌に吸着した有機物のサイズ分布に与える影響
Effects of microorganisms and minerals on size distribution of organic matter adsorbed tosoil
保原 達 1∗ ; 長谷川 裕己 2 ; 藤田 恭平 1 ; 佐藤 貴之 3 ; 今井 章雄 3 ; 小川 浩史 4 ; 伊藤 彰英 5 ;
阿江 教治 1
HOBARA, Satoru1∗ ; HASEGAWA, Yuki2 ; FUJITA, Kyouhei1 ; SATOU, Takayuki3 ; IMAI, Akio3 ;OGAWA, Hiroshi4 ; ITO, Akihide5 ; AE, Noriharu1
1

酪農学園大学, 2 北海道大学, 3 国立環境研究所, 4 東京大学, 5 麻布大学
Rakuno Gakuen University, 2 Hokkaido University, 3 National Institute for Environmental Sciences, 4 University of Tokyo,
5
Azabu University
1

土壌における有機物吸着は、陸上生態系における炭素隔離において重要なメカニズムの一つである。しかしながら、吸着性の有機物が分解プロセスにおいてどのように生成されるかについてはよく分かっていない。本研究では、分解における土壌中の吸着性有機物のサイズ分布の変化や、微生物や鉱物がその変化に与える影響について明らかにする。我々は、まず炭素をほとんど含まない土壌を用いて 3 種のリターの分解実験をそれぞれ行い、その土壌の抽出性有機物のサ
イズ分布をサイズ排除カラムを装着した HPLC（HPSEC）を用いて分析した。抽出された有機物の分子量分布は、植物種によらず主に二つのレンジ、100kDa-200kDa 付近と、0.5kDa-20kDa 付近（いずれもタンパク質分子量ベース）、に集中していた。これらのレンジの幅は、分解過程が進むにつれ狭まっていった。この分子量分布（MWD）の変化は、シク
ロヘキシミドを土壌に加えた場合には現れたものの、クロラムフェニコールを土壌に加えた場合にはみとめられなかった。このことから、バクテリアが、この変化に影響していることが示唆された。また、この二つの典型的なレンジに鉱物が与える影響を明らかにするため、HPSEC 溶出液を画分したサンプルを ICP/MS を用いて金属分析した。その結果、鉄の MWD が有機炭素のそれと非常に似ていた。これらの結果は、バクテリアと鉄が、分解有機物中の吸着性有機物のサイズ分布にとって重要な役割を果たしていることを示唆している。
キーワード: 土壌微生物, 土壌鉱物, 土壌炭素, 有機物吸着, 分子量分布
Keywords: Soil microorganisms, Soil minerals, Soil carbon, Organic matter adsorption, Molecular weight distribution

1/1

MIS03-P08

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

日本の火山灰土におけるイオウ化合物の蓄積機構
Accumulation of sulfur compounds in Japanese volcanic soils
谷川 東子 1∗ ; 橋本 洋平 2 ; 山下 尚之 3 ; 野口 享太郎 4 ; 吉永 秀一郎 1 ; 高橋 正通 4
TANIKAWA, Toko1∗ ; HASHIMOTO, Yohey2 ; YAMASHITA, Naoyuki3 ; NOGUCHI, Kyotaro4 ;YOSHINAGA, Shuichiro1 ; TAKAHASHI, Masamichi4
1

森林総合研究所関西支所, 2 東京農工大学, 3 アジア大気汚染研究センター, 4 森林総合研究所
Kansai Research Center, Forestry and Forest Products Research Institute, 2 Tokyo University of Agriculture and Technology,
3
Asia Center for Air Pollution Research, 4 Forestry and Forest Products Research Institute1

Volcanic soils are found in Asian countries, particularly within the circum-Pacific volcanic belt. Their unique chemical properties are expected to contribute to sulfur (S) retention. Although S is an essential element for plants and microorganisms, there
is little information about S dynamics in forest ecosystems of Asian countries. The aim of this study is to characterize S accumulating systems in Japanese volcanic soil from the following four aspects: i) S pool sizes; ii) spatial S distribution in a catchment;iii) organic S transformation processes; iv) upbuilding/topdown pedogenesis.
To achieve the purposes, we investigated i) S pools of forested volcanic soils from 0-2m depth in the Kanto district; ii) the
spatial variations of S concentration in a small drainage basin covered by volcanic soil by a geostatistical analysis; iii) organic S
transformation rates in incubation experiments; iv) the vertical distribution of S species using K-edge X-ray absorption near-edge
structure (XANES) spectroscopy of S species in Melanudands developed above tephra Nt-S, dated at 14-15 cal. ka by upbuilding
pedogenesis.
The above four studies showed unique S accumulating systems of volcanic soils in Japanese forests as follows: i) volcanic
soils accumulate larger amounts of S than other soil orders previously studied in North America and Europe. Forty percent oforganic S was composed of Al-associated forms. Significant correlation between S species and pedogenic minerals suggests thatlarge amounts pedogenic minerals lead to the large S pools. ii) Geostatistical analysis revealed the strong similarity of the spatial
patterns of total S concentration and those of the pedogenic minerals throughout the catchment area. More S accumulated in theresidual soils (ash soils) on the upper slopes of the catchment than in the colluvial soils of the lower slopes. The most importantfactor that influenced the distribution of soil S in the catchment was the degree to which volcanic ash was retained in the soils,
as reflected by the abundance of the pedogenic minerals derived from volcanic ash deposits. iii) During incubation, the concentration of ester sulfate-S increased in the soils with high concentrations of the pedogenic minerals, whereas the concentration of
Carbon (C)-bonded S decreased in all soils. The decrease rate of ester sulfate-S concentrations was negatively correlated withthe pedogenic mineral contents. Therefore, when C-bonded S was transformed into ester sulfate-S, complete mineralization to
inorganic sulfate might be inhibited, because ester sulfate-S was probably stabilized due to organo-mineral association. iv) The
striping distribution patterns of various S fractions were shown in the soil with upbuilding pedogenesis. The predominant S
species was highly oxidized S in ester sulfates and inorganic sulfates (+6 oxidation state), nevertheless, proportions of S with
reduced and intermediate oxidation states increased episodically. A close correlation was found between ester sulfate-S concentrations and Al-associated organic S concentrations; indeed, the concentrations themselves were roughly similar.
These results suggest that accumulation/transformation of S compounds in Japanese forests is controlled by the pedogenic
minerals derived from volcanic ash. Episodic deposits of volcanic ash and eolian dust might trap detritus and humus beneaththem during the buildup of the soil surface. The organic S compounds in this material might be decayed as topdown pedogenic
processes in the soils. Therefore, the soils with upbuilding pedogenesis have high heterogeneity of S compounds. Volcanic soils
might have high ability to retain ester sulfates as Al-associated organic S during transformation processes.

キーワード: 森林土壌, 遊離酸化物, ジオスタティスティカ解析, 放射光分析, XANES, 形態変化
Keywords: Al and Fe hydrous oxides and short-range ordered minerals, forest soils, geostatistical analysis, K-edge X-ray absorption near-edge structure (XANES) spectros, pedogenic minerals, transformation of organic S

1/1

MIS03-P09

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

サブミクロスケールで起こる有機物と鉱物の相互作用の可視化
Visualization of organic matter binding on poorly-crystalline mineral phases in soil submicron organo-mineral matrix
浅野 眞希 1∗ ; 和穎 朗太 2 ; 武市 泰男 3 ; 前田 誠 4 ; 菅 大暉 5 ; 山口 紀子 2 ; 平舘 俊太郎 2 ; 高橋 嘉夫 5
ASANO, Maki1∗ ; WAGAI, Rota2 ; TAKEICHI, Yasuo3 ; MAEDA, Makoto4 ; SUGA, Hiroki5 ;YAMAGUCHI, Noriko2 ; HIRADATE, Syuntaro2 ; TAKAHASHI, Yoshio5
1

筑波大学, 2 （独）農業環境技術研究所, 3 高エネルギー加速器研究所, 4 広島大学, 5 東京大学
University of Tsukuba, 2 National Institute for Agro-Environmental Sciences, 3 3Institute of Materials Structure Science, HighEnergy Accelerator Research Organization, 4 Hiroshima University, 5 The University of Tokyo

1

Soil organic matter (SOM) accounts for a major portion of terrestrial C and is considered to be stabilized against microbial
degradation due partly to its interaction with soil minerals. Significant control of poorly-crystalline mineral phases on soil organic
matter turnover as well as its storage has been shown based on field correlation studies and incubation experiments. Yet howorganic compounds of microbial and plant origins interact with poorly-crystalline and other mineral phases within soil aggregate
structure at the spatial scale relevant to microbial extracellular enzymes (tens of nanometers) remain unclear. Here we focusedon the sonication-resistant particles that are enriched in organic matter (OM) from an Andisol, the soil order characterized byhigh contents of OM and poorly-crystalline minerals and high aggregate stability, and tested the hypothesis that submicron-scale
OM distribution within a soil particle is controlled by poorly-crystalline minerals using scanning transmission X-ray microscopy(STXM) and near-edge X-ray absorption fine structure (NEXAFS) as well as scanning and transmission electron microscopy(SEM, TEM). We will demonstrate that the combination of synchrotron and other spectroscopic techniques used here is a powerful approach to directly examine soil organo-mineral associations occurring at submicron scale, which can contribute to enhance
our mechanistic understanding of SOM stabilization processes.
キーワード: 土壌有機物, 土壌団粒, 非晶質鉱物, 火山灰土壌, STXM
Keywords: soil organic matter, aggregate, poorly-crystalline minerals, Andisols, scanning transmission X-ray microscopy

1/1MIS03-P10

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

炭素貯留に最適な植物残渣の燃焼・炭化程度
Optimal thermolysis condition for soil C storage upon plant residue burning
梶浦 雅子 1∗ ; 和穎 朗太 1 ; 林 健太郎 1
KAJIURA, Masako1∗ ; WAGAI, Rota1 ; HAYASHI, Kentaro1
1
1

農業環境技術研究所
National Institute for Agro-Environmental Sciences

Crop residues are often burned in the field and mixed into soil. Yet the impact of this agricultural practice on soil carbon (C)sequestration remains unclear due to the heterogeneity in burning condition and the difficulty in monitoring the biodegradationof burned residues that include char in fields. Thus, identifying the quantitative relationship among burning condition, residue
chemistry, and biodegradability is a critical first step. The residue burnt at higher temperature reduces greater mass yet theremaining residue becomes more recalcitrant via carbonization. The residue burnt at low temperature, on the other hand, maintaingreater mass which experiences faster biodegradation due to its lability. A corollary to the trade-off relationship is the presence ofthreshold temperature range above and below which the residue carbon remained after experiencing both thermal decompositionand subsequent biodegradation is strongly reduced. To test the idea, we thermolyzed residues (rice straw and husk) at different
temperatures (200-600 ℃) under two oxygen availability, and measured the changes in thermal C loss and the biodegradabilityof thermally-altered residues by laboratory aerobic incubation. The empirical model accounting for the both decomposition
processes showed the emergence of threshold temperature range (330-400 ℃ at 102 -103 year time scale) due to the expectedtrade-off relationship. This temperature range corresponded to the major loss of O-alkyl-C (cellulose and hemicellulose) andincrease in aromatic-C. These findings show that the thermally-altered residues formed by the threshold range contributes themost to the long-term soil C storage in fire-prone ecosystems and may help to develop C sequestration strategy which takes
advantage of field biomass burning, a widespread land practice in many parts of the world.
キーワード: 炭, 13C NMR, 稲残渣, 酸素条件, 熱分解
Keywords: black carbon, 13C NMR spectroscopy, rice residues, oxygen concentration, pyrolysis

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MIS03-P11

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

土壌有機物と団粒の階層構造を再考する：火山灰土壌を例にSoil organic matter and aggregate hierarchy revisied: a case study using an Andisol和穎 朗太 1∗ ; 浅野 眞希 2 ; 梶浦 雅子 1 ; 井上 弦 3 ; 早川 智恵 4 ; 平舘 俊太郎 1
WAGAI, Rota1∗ ; ASANO, Maki2 ; KAJIURA, Masako1 ; INOUE, Yudzuru3 ; HAYAKAWA, Chie4 ;HIRADATE, Syuntaro1
1

農業環境技術研究所, 2 筑波大学生命環境系, 3 埼玉大学大学院理工学研究科, 4 東京大学農学生命科学研究科
National Institute of Agro-Environmental Science, 2 University of Tsukuba, Graduate School of Life & Environmental Sciences,
3
Saitama University, Graduate School of Science and Engineering, 4 The University of Tokyo, Graduate School of Agriculturaland Life Sciences
1

Soil aggregate structure is likely to exert fundamental control on soil biology (e.g., microbial activity and community composition) and soil biogeochemistry including the stabilization and mobilization of soil organic matter (SOM). Aggregate hierarchy
concept (Tidall and Oades, 1982) has been verified for most temperate and tropical soil types except for Andisols developed fromtephra and volcanic rocks are known for strong aggregate stability and high SOM storage capacity. We recently showed the firstevidence of hierarchical structure in Andisol (Asano and Wagai, 2013). After maximum dispersion (achieved only after 5 kJ/mL
sonication following sodium saturation), most of macro- and micro-aggregates were broken down to much smaller particles(<0.2 and 0.2-2 um) that accounted for dominant proportion of total C, N, and extractable phases of Al, Si, and Fe. These <2um
particle-size fractions appeared to act as persistent binding agent, contributing to the high physical stability of the aggregates.
When the same soil was fractionated by density, the aggregates resistant to mechanical shaking (i.e. higher level in hierarchicalstructure) showed progressive changes in chemistry along density gradient (Wagai et al. 2014). Among the intermediate density
fractions (2.0-2.5 g/cc) where >80% of total C and N and the extractable metals are present, we found general decrease in C:N
ratio and delta 14C and concurrent enrichment of 13C and 15N in accord with previous reports.
The next key question is how the particle-size fractions isolatable after the maximum dispersion are assembled together toform the shaking-resistant aggregates of different density. We attempted to answer this question by examining the organic andinorganic chemistry (C, N, 13C, 15N, d14C, 13C-NMR, extractable metals) and the surface characteristics (SSA by N2-BET
and XPS) of the size and density fractions. We will also discuss the nature of organo-mineral interactions inferred from ourresults and compare it with the previously-suggested concepts such as aggregate hierarchy (Tidall and Oades, 1982), and zonal
layering model (Kleber et al. 2007).
References:
Asano, M and Wagai, R. (2014) Evidence of aggregate hierarchy at micro- to submicron scales in an allophanic Andisol.
Geoderma. 216, 62-74.
Kleber, M. et al. (2007) A conceptual model of organo-mineral interactions in soils: self-assembly or organic molecular fragments into zonal structures on mineral surfaces. Biogeochem. 85: 9-24.
Tisdall, J.M. and Oades, J.M. (1982) Organic-matter and water-stable aggregates in soils. J. Soill Sci. 33: 141-163.
Wagai, R. et al. (2015) Nature of soil organo-mineral assemblage examined by sequential density fractionation with and without sonication: Is allophanic soil different? Geoderma 241-242: 295-305.

Keywords: soil carbon, soil nitrogen, carbon sequestration, aggregation, organo-mineral interaction, isotope

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MIS03-P12

会場:コンベンションホール

時間:5 月 27 日 18:15-19:30

Soil moisture variations for landscape trees under humid tropical conditions
Soil moisture variations for landscape trees under humid tropical conditions
Jim C.Y.1∗
JIM, C.y.1∗
11

Department of Geography, University of Hong Kong
Department of Geography, University of Hong Kong

Compact urban development in Hong Kong has left little plantable spaces for amenity vegetation. Containers could permit tree
growth in cramped sites with masses of buried utilities. This study evaluated the moisture variations in landscape tree containers
in urban Hong Kong. Stratified random sampling selected 12 containers of different geometry. Soil moisture was obtained bya Time Domain Reflectometry (TDR) probe. Volumetric soil moisture content was measured at 5 cm depth intervals every two
weeks for one year. Topsoil and subsoil samples were taken to analyze key physical and chemical properties. The soil mix,
derived from decomposed granite amended with organic material, were highly stony with high sand content and loamy sandtexture. The mean bulk density of 1.72 Mg/m3 suggested degraded structure and compaction to about 33 per cent total porosity.
Despite having more organic matter, the topsoil was more compacted and less porous than subsoil mainly due to prolonged
rainsplash impact. Inadequate organic matter and excessive sand are unfavorable to soil structure formation and maintenance.
The dominant coarse sand could support more air capacity pores to promote infiltration, drainage and aeration, with limited
availability of medium pores for storage of plant-available water. Moisture content closely followed the rainfall regime withpronounced variations between dry and wet seasons and episodes. Moisture increased notably with depth in most containers
due to less compacted subsoil. Occurrence of lithologic discontinuity in some sites retarded downward water movement andcreated perched water table. Waterlogging occurred periodically in subsoil due to heavy and prolonged rainfall in the wet season,compounded by blocked drain holes with impeded drainage. Sites shaded from direct sunshine had more water and less temporalfluctuations, indicating the influence of elevated temperature on evapotranspiration. The applications of the findings to container
design, soil management for urban trees were explored.

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