MIS03-01

会場:104

時間:5 月 27 日 09:00-09:45

Volcanic islands as model systems to quantify pedogenic thresholds and determine theirimpact on Polynesian land-use
Volcanic islands as model systems to quantify pedogenic thresholds and determine theirimpact on Polynesian land-use
CHADWICK, Oliver1∗
CHADWICK, Oliver1∗
1
1

University of California, USA
University of California, USA

Soils and weathering profiles are complex emergent features at the surface of terrestrial Earth. They form a boundary layer
hosting the chemical and physical interaction of biology and hydrology with rock. Soil development derives from the dissipationof chemical energy through reaction with rock minerals; few of the original reactants survive, but they are replaced by secondary
products unique to the weathering environment. Soil processes filter and transform gasses and liquids passing through them,which in turn leads to chemical and mineralogical evolution of the fabric of soil itself. Soil chemical reactions are controlled
by a number of feedbacks that buffer the system from rapid changes in external inputs, however there are limits beyond which
the chemical system rapidly shifts into a new chemical domain governed by different buffer reactions. Globally soil distribution
patterns are underlain by specific soil process domains that are separated by pedogenic thresholds at points of domain failure.
Considering how soil process domains and thresholds determine the global distribution of properties, which control everythingfrom agricultural productivity to carbon sequestration is a primary research focus for modern biogeochemistry. Soils are complex
systems, which makes it difficult to develop clear understanding of how specific driving factors control soil process domains. It
is common therefore to develop model systems that allow us to tackle specific questions with fewer complications. Here I discuss
the use of volcanic islands in the Pacific Ocean as a model system to study how pedogenic thresholds control phosphorus andcalcium availability to plants. I then combine that knowledge with archeological information to understand how the geographic
constraints imposed by these thresholds determined Polynesian land use and agricultural productivity. As Polynesians radiatedacross the Pacific they encountered islands that presented many different local environments ranging from reef protected lagoons
and minimal high island terrain to high volcanic islands with still active volcanoes. They brought with them an agricultural starter
kit, but from there on they needed to adapt to their new surroundings. They practiced two major types of intensive agriculture:
non-irrigated dryland and flooded-field irrigated farming. Typically young islands had soils with rich nutrient stores, whereas
older islands had depleted soils that were not productive. By contrast, young islands had few large valleys to support irrigatedagriculture, whereas the older ones had broad valleys allowing development of highly productive irrigation systems. Thus cultivators in rainfed systems brought their crops to areas where near-surface rocks were still weathering and supplying nutrients suchas calcium and phosphorus, whereas in irrigated systems flowing water brought the products of weathering to crops. The contrast
had profound implications for the development of culture across Polynesia. Behind these anthropological observations lies anequally fascinating story about how dramatically different soil properties are produced by non-linear responses to environmental
forcing. In this talk I will explore the pedology of volcanic islands and relate it to pre-industrial human land-use decisions.
キーワード: Soil Chemistry, Biogeochemistry, Andisols, Soils
Keywords: Soil Chemistry, Biogeochemistry, Andisols, Soils

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MIS03-02

会場:104

時間:5 月 27 日 10:00-10:30

Can soil properties alone predict ecosystem processes?
Can soil properties alone predict ecosystem processes?
北山 兼弘 1∗KITAYAMA, Kanehiro1∗
1
1

京大・森林生態
Forest Ecology, Kyoto University

Soils are a reservoir of nutrients, which supplies plants with essential elements. Soil chemical properties can change spatiallyand temporary in relation to parent materials, climate and pedogenesis as a function of time. In places, the concentrations ofessential elements in soils are extremely impoverished, which can eventually limit the net primary productivity of terrestrial
ecosystems. Accounts by Elser et al. (2007), Vitousek et al. (2010) and many others indicate that available P is depleted indeeply weathered soils in the tropics due to a long process of geochemical occlusion and losses without substrate rejuvenationand that P limits the productivity of many tropical rain forests.
Colleagues and I have been extensively studying soil P fractions and productivity in Bornean tropical rain forests. Indeed,
the concentrations of soil total P or labile P fraction are generally impoverished in comparison to temperate ecosystems but canstill vary greatly reflecting parent materials or the status of pedogenesis. For instance, the concentrations of soil total P in seventropical rain forests below 700 m asl in north Borneo are generally low, but range from 66 to 512 (μ g/g). That of Bray-1
extractable P ranges from 0.2 to 4.2 (μ g/g). Yet, above-ground net primary productivities of these forests are remarkably highand converge to a narrow range. Therefore, soil chemical properties do not correlate with productivity in plausibly P-limited
tropical rain forests. Why soil P fractions cannot explain productivity?
We ecologists consider net primary productivity as a fundamental ecosystem process, which is expressed as the rate of net
carbon fixation in an ecosystem context. Trees invest P for carbon fixation and the efficiency of the carbon fixation is expressedby the ratio of C flux to P flux, i.e. P-use efficiency in productivity. In these forests, P-use efficiencies greatly vary by 5-foldfrom 800 to 4000 (gC/gP) indicating that trees can adjust to the magnitude of P deficiency to maintain productivity. This is the
major reason why soil P fractions cannot explain productivity.
Biological mechanisms to explain the enhancement of P-use efficiencies are two fold, one is the efficiency of photosynthetic
C fixation per unit P in leaves and the other is the residence time of P in tree bodies. Colleagues and I investigated relative
importance of these two mechanisms and found that the variation of residence time of P can much better explain the variation ofP-use efficiency. Tropical trees increase the residence time of P in their bodies by increasing leaf life span and also by increasing
P resorption from senescing leaves when facing to increasing P deficiency. We consider these are the two important plant traits
which plants have acquired as adaptation. Our studies imply that understanding adaptive mechanisms as well as soil chemical
properties is essential to understand ecosystem processes.
Keywords: Adaptation, Biogeochemistry, Net primary productivity, Nutrient-use efficiency, Soil P fractions, Tropical rain forest

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MIS03-03

会場:104

時間:5 月 27 日 10:30-10:45

熱帯山地林における低リン土壌への適応としての樹木根の形態と生理特性の関係
Linkage of root physiology and morphology as an adaptation to soil phosphorus impoverishment in tropical montane forests
潮 雅之 1∗ ; 藤木 泰斗 2 ; 日高 周 3 ; 北山 兼弘 4
USHIO, Masayuki1∗ ; FUJIKI, Yasuto2 ; HIDAKA, Amane3 ; KITAYAMA, Kanehiro41
1

龍谷大学理工学部, 2 三菱 UFJ リサーチ&コンサルティング, 3 北海道大学, 4 京大農学研究科
Ryukoku Univ., 2 MURC, 3 Hokkaido Univ., 4 Grad. Sch. Agric., Kyoto Univ.

ボルネオ熱帯林はリン欠乏土壌の上に成立しているにも関わらず、高いレベルの生産性やバイオマスを維持している。
樹木根のリン獲得機構は森林の生産性/バイオマス維持に重要な貢献を果たしている可能性がある。しかしながら、樹木
地上部の特性（例えば葉の栄養塩濃度や光合成特性）に比べると樹木根の土壌リン欠乏に対する適応は分かっていない
ことが多い。本研究では、樹木根の土壌リン可給性への応答を明らかにするため、土壌リン可給性に大きな違いがある
３つのボルネオ熱帯山地林で根の形態的・生理的特性の変化を測定した。具体的には、３つの森林で合計３７優占樹種・１４９個体の樹木実生を採取し、根のリン酸分解酵素活性（有機態リンから無機態リンを獲得する活性の指標）と根の表面積、直径、組織密度を測定した。
その結果、樹木群集スケールでは土壌リン可給性が減少するにともない、根のリン酸分解酵素活性と根の単位重量あたりの表面積が上昇し、根の直径は減少した。この関係は複数の森林サイトに分布する単一の樹木種に着目しても定性的には同じだった。根のリン酸分解酵素活性は根の表面積と有意な正の相関を示し、根の直径と有意な負の相関を示した。これは細い根が高いリン酸分解酵素活性を保持していることを示唆している。さらに我々は種レベルで根のリン酸分解酵素活性と葉のリン濃度と比較し、有意な負の相関を見出した。これは根のリン獲得機構が葉のリン濃度に影響している、あるいは葉のリン濃度が根のリン獲得機構に影響を与えていることを示唆している。
結論として、根の生理的・形態的特性は土壌リンの可給性にともなって変化した。さらに、樹木根の特性は葉のリン濃度と同調して変化していた。土壌リン可給性の変化に伴う樹木の地上部・地下部特性の同調的かつ適応的な変化がボ
ルネオ熱帯山地林での生産性やバイオマスの維持に貢献しているのかもしれない。
キーワード: リン酸分解酵素活性, 植物-土壌相互作用, 樹木根, 根表面積, 土壌リン可給性, 熱帯山地林
Keywords: Phosphatase activity, Plant-soil interactions, Tree roots, Root surface area, Soil phosphorus availability, Tropicalmontane forests

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MIS03-04

会場:104

時間:5 月 27 日 11:00-11:15

比重分画した黒ボク土におけるリンの蓄積分布と化学種
Distinctive pools and chemical species of phosphorus among density fractions of allophanic and non-allophanic Andisols
髙本 慧 1 ; 橋本 洋平 1∗ ; 和穎 朗太 2 ; 浅野 眞希 3
TAKAMOTO, Akira1 ; HASHIMOTO, Yohey1∗ ; WAGAI, Rota2 ; ASANO, Maki3
1
1

東京農工大学, 2 独・農業環境技術研究所, 3 筑波大学生命環境系
Tokyo University of Agriculture and Technology, 2 National Institute for Agro-Environmental Sciences, 3 University of Tsukuba

Andisols with abundant aluminum (Al) and iron (Fe) oxyhydroxides are characterized by a high phosphorus (P) retention
capacity. Such property leads to a significant inhibition of plant growth in Andisols unless properly managed. Andisols areclassified into two types in accordance with the difference in the clay mineral compositions. One type is referred to as allophanic
Andisols, in which allophane and imogolite are present in the clay fraction. The other type is referred to as non-allophanic
Andisols, in which Al- and Fe- humus complexes and 2:1 phyllosillicates are predominant. Based on the result of chemical
extraction, it has been suggested that these clay minerals appear to contribute to P retention capacity of Andisols. Separating
the different soil minerals in accordance with their density can limit the number of P-bearing phases, facilitating characterizationof species and accumulating pools of P. The objective of this study was to characterize the species and distinctive pools of P
in allophanic and non-allophanic Andisols using density separations in combination with sequential extraction and solution 31 P
nuclear magnetic resonance (NMR) spectroscopy.
Allophanic and non-allophanic Andisols collected from Tsukuba and Osaki, respectively, were fractionated by sodium polytungstate into five density levels including 1.6-1.8, 1.8-2.0, 2.0-2.25, 2.25-2.5, and >2.5 g cm−3 . Phosphorus in each density
fraction was extracted sequentially by deionized water, 0.5 M NaHCO3 , 0.1 M NaOH and 1.0 M HCl. After the extracts were
filtered, the concentration of inorganic P (Pi ) in all fractions was determined colorimetrically with a molybdenum blue method.
The concentration of total P (Pt ) in each fraction was determined by the same method after the solution was treated using H2 SO4 persulphate digestion. The concentration of organic P (Po ) was calculated as the difference between Pt and Pi of each fraction.
The total concentration of P was similar in the allophanic and non-allophanic Andisols (6.2 g kg−1 ). A large proportion of Pi
and Po in the bulk and each density fraction was extracted by NaOH, indicating that P in both Andisols was mainly associatedwith Al and Fe (oxy)hydroxides. The density fraction that accumulates P was contrastingly different between allophanic andnon-allophanic Andisols where over 90% of Pi and Po in the former was accumulated in the >2.0 g cm−3 fraction, whereas
about 70% of Pi and Po in the latter was found in the <2.0 g cm−3 fraction. According to the 31 P-NMR analysis, ortho-P
monoesters were the primary organic P species for the allophanic and non-allophanic Andisols, although it was 2-folds moreabundant in the latter than the former. In the non-allophanic Andisols, myo-inositol hexakisphosphate, an ortho-P monoester,
was accumulated in the 1.8-2.25 cm−3 fraction.

キーワード: リン, NMR, 化学種
Keywords: phosphorus, NMR, chemical speciation

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MIS03-05

会場:104

時間:5 月 27 日 11:15-11:30

日本の海洋島において野生化ヤギと海鳥の活動が表層土壌の化学的特性におよぼす
影響
Influence of feral goat and seabird activities on chemical properties of surface soils on an
oceanic island in Japan平舘 俊太郎 1∗ ; 森田 沙綾香 1 ; 畑 憲治 2 ; 大澤 剛士 1 ; 須貝 杏子 2 ; 可知 直毅 2
HIRADATE, Syuntaro1∗ ; MORITA, Sayaka1 ; HATA, Kenji2 ; OSAWA, Takeshi1 ; SUGAI, Kyoko2 ;KACHI, Naoki2
1
1

独立行政法人農業環境技術研究所, 2 首都大学東京
National Institute for Agro-Environmental Sciences, 2 Tokyo Metropolitan University

Ogasawara Islands, subtropical oceanic islands in north-western Pacific of Japan, have been listed as Natural World Heritage
by UNESCO since 2011 because of their valuable ecosystems sustaining many indigenous spices including plants and snails.
Nakoudojima Island and its peripheral reefs are the important components of the heritage, but the island has been exposed tothe serious influence of soil erosion damaging the indigenous ecosystems. Many areas on the island have been covered withnative forests before the introduction of goats (Capra hircus ) of ca. 200 years ago. The introduced goats had been naturalizedon the island since 1945 at the latest, and they had destroyed the native vegetation by grazing and trampling, resulting in a shiftof the native forests into grasslands and loss of the surface soils. To fix the problem, all the feral goats on the island had been
eradicated in 1999. Although the recovery of seabird nesting for brown booby (Sula leucogaster ) and wedge-tailed shearwater(Puffinus pacificus ) has been observed, the soil erosion has still been serious and plant biomass has been very low in some placeson the island at least in 2014.
To conserve the indigenous natural ecosystem and help the recovery of the natural vegetation, we conducted field survey andinvestigated the chemical properties of surface soil (0 ‐ 5 cm) and aboveground plant biomass in relation to the topography ofthis island. Under grassland vegetation where influence of feral goat would have been severe, the chemical properties of surface
soils, such as soil pH value, total C and N contents, exchangeable acidity, and plant-available phosphate (Bray II P), were highlyvariable even in a small area. By comparing soil profile characteristics under natural and disturbed vegetation and distribution
patterns of these soils on the island, the changes in the soil chemical properties were reasonably assigned to the effect of soil
erosion caused by feral goats for increased soil acidity (mainly found in inland valley area) and to the effect of seabird activities
for increased Bray II P and soil acidity (mainly found in outer rim area with high altitude). It was also clarified that the high soil
acidity was significantly related to the low productivity of plant biomass. Soil erosion would have removed surface soils having
weak acidity and exposed subsoils having strong acidity to the ground surface, resulting in inhibition of plant growth and delayof vegetation recovery. Based on the findings obtained in the present study, several options were proposed to stop soil erosion
and to recover the vegetation, although careful preliminary examination would be necessary for applying them.
キーワード: 媒島, 世界自然遺産, 土壌中の植物有効態リン酸, 土壌の置換酸度, 外来種, 土壌流出
Keywords: Nakoudojima Island, natural world heritage, plant-available phosphate in soils, soil exchangeable acidity, exotic
species, soil erosion

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MIS03-06

会場:104

時間:5 月 27 日 11:30-11:45

日本におけるテフラ由来土壌の生成
Pedogenesis of tephra-derived soils in Japan井上 弦 1∗INOUE, Yudzuru1∗
1
1

埼玉大学大学院理工学研究科
Graduate School of Science and Engineering, Saitama University

In Japan, there are still 110 active volcanoes today, which occupy approximately 7 percent of those in the world. Some
volcanoes in Japan are erupting now and continuing deposition of tephras on the land surface. They will become the parent
material of the soils. Of the soils in Japan, tephra-derived soils ‘Kuroboku soils (Andosols/Andisols)’ are the second-most common group under the main classification scheme in usage, the Unified soil classification system of Japan (FCSCN, 2003). Many
tephra-derived soils are distributed near and around numerous volcanoes in Japan. Tephra-derived soils composed of black soils(abundant humic soils), brown soils (mainly brown loamy soils: including tephric loess and loess), and Regosols (Tephric) (FAO,
2006) (very weakly developed mineral soils). It has been suggested that the black soils develop when the supply of organic
matter by Gramineae grass exceeds the rate of addition of tephra parent materials (Inoue, 2002). It is usually stabilized by theformation of allophane and Al- (or Fe-) humus complexes. Origin of the abundant humus is confirmed by the high correlation
between organic carbon content and phytolith content of Gramineae grass (Inoue et al., 2000; 2001 etc.). Most of the Japanese
Holocene tephra-derived soils are rich in humus. Older buried humic-rich soils can also be observed in Late Pleistocene tephrasoil sequence in Japan (Inoue et al, 2011a). One of the tephra-derived soils ‘brown soils’ having poor in humus include anaeolian-reworked tephras (tephric loess; Pullar and Pollok, 1973) as main parent material. Tephric loess occurs in tephra-soil
sequences in Japan and is also interlayered with ‘background’ loess derived from long-term (continuously-deposited) loess (aeolian dust) deposition from Gobi, Taklamakan desert, and the loess plateau in central Asia (Inoue and Naruse, 1987). This loessis barely observed in Japan. Sase and Hosono (1996) shows that pedogenesis of brown soils occurs under the forest vegetationby using vegetation changes from phytolith composition in tephra-soil sequence.
Pedogenesis includes both ‘topdown’ and ‘upbuilding’ models (Almond and Tonkin, 1999; Lowe, 2000; Inoue, 2001). Topdown pedogenesis is ‘classical’ soil formation that occurs by leaching, illuviation, and other processes that form andic materials
with horizons developing in a downward-moving front. Upbuilding pedogenesis operates where the soil forms while additions
to the soil surface of such materials as tephra or loess occur. If additions are sufficiently slow ̶ typically as thin incremental
deposits in distal areas ̶ then topdown pedogenesis continues while the land surface slowly rises (referred to as ‘developmental
upbuilding’). If additions are thick or frequent, as typically occurs nearer volcanic sources, then the antecedent soil is buried andisolated, and soil formation begins again on the new materials at the land surface (‘retardant upbuilding’) (Inoue et al., 2011b;
Lowe et al., 2008). The profile character is thus determined by the interplay between the rate at which tephras are added to
the land surface and topdown processes. Understanding Andosol/Andisol genesis thus often requires a stratigraphic approachcombined with an appreciation of buried soil horizons and polygenesis (Lowe and Tonkin, 2010). The terms ‘developmental
upbuilding’ and ‘retardant upbuilding’ were first used by Johnson and Watson-Stenger (1987) and Johnson et al. (1990) as partof their dynamic-rate model whereby soils evolve by ‘ebb and flow’ through time (Schaetzl and Anderson, 2005). As mentioned
above, most of the tephra-derived soils in Japan are formed by upbuilding pedogenesis and may be described as multisequal soils.
At the present day, theories concerning pedogenesis of tephra-derived soils in Japan are changing from long-established theories. The soils in the regions having numerous active volcanoes occur distinctive pedogenesis unlike in non-volcanic regions.
キーワード: 土壌, テフラ, 土壌生成, テフラ由来土壌, 黒ぼく土, 植物珪酸体
Keywords: soil, tephra, pedogenesis, tephra-derived soil, Andosols/Andisols, phytolith

1/1MIS03-07

会場:104

時間:5 月 27 日 11:45-12:00

7300 年前のアカホヤ火山灰堆積後に降水量と気温が屋久島の土壌―植生系の形成に与えた影響
Effect of climate on vegetation-soil system after volcanic ash deposition 7300 years ago
on Yakushima Island
向井 真那 1∗ ; 相場 慎一郎 2 ; 北山 兼弘 1
MUKAI, Mana1∗ ; AIBA, Shin-ichiro2 ; KITAYAMA, Kanehiro1
1
1

京都大学大学院農学研究科, 2 鹿児島大学大学院理工学研究科
Graduate School of Agriculture, Kyoto University, 2 Guraduate School of Science and Engineering, Kagoshima University

屋久島では現在、標高傾度に沿って植生の垂直分布が見られる。7300 年前に屋久島の北西 20km に位置する鬼界カルデ
ラの噴火により噴出したアカホヤ火山灰がほぼ全域に堆積し、当時の植生は壊滅的な影響を受けたと言われる。従って、現在の屋久島の植生は 7300 年間の土壌生成とともに垂直的に分化、成立したものと考えられる。陸上生態系（土壌−植生系）の形成には、気候、地形、生物、母材、時間という 5 つの独立した要因が関わる。屋久島では母材や時間が一定であり、現在の植生垂直分布には気候が大きな影響を及ぼすと考えられるが、気温と降水量のどちらがより強く関わっているのかは明らかではない。そのため、7300 年前に火山灰が堆積した後、気温と降水量が土壌−植生系の成立に与えてきた影響について、土壌栄養塩とリターの栄養塩利用効率との関係を通して検証することを本研究の目的とした。
異なる標高に設定した 7 つの永久調査地から表層土壌（0-10、10-20cm）を採取し、これらの土壌の化学分析を行った。
Tiessen & Moir（1996）のリン連続抽出法に従いリンを分画し、画分毎のリン濃度を決定した。また、土壌から 1.5N のKCl 溶液を用いて交換態陽イオンと無機態窒素を抽出し、それらの濃度を決定した。これらの森林から新鮮なリターを採集し、リター中のリンと窒素の濃度を測定した。リター生産におけるリンと窒素の栄養塩利用効率として、リターのリンと窒素の濃度の逆数を使用した。得られた値と、降水量と気温との関係を調べた。降水量と気温は、国土交通省国土政策局が公表している国土数値情報平年値メッシュデータを各森林の GPS 情報と照合して入手した。
土壌の全リン濃度と無機態窒素濃度は、それぞれ降水量よりも気温と強い相関があった（リン：R=0.77 p<0.05、 窒
素：R=0.72 p=0.07 （10-20cm 深 気温との相関））。リンの画分の中で、特に吸蔵態リンは温度と有意な正の相関が見られた（R=0.76 p<0.05（10-20cm 深））。一方、土壌中の交換態カルシウムとマグネシウムの濃度は、気温よりも降水量との相関が強かった（カルシウム：R=-0.88 p<0.01、マグネシウム：R=-0.86 p<0.05 （10-20cm 深 降水量との相関））。また、土壌全リン濃度と無機態窒素濃度にはそれぞれの栄養塩利用効率と負の相関があった（リン：R=-0.82 p<0.05、窒
素：R=-0.68 p=0.09）
リンは森林生態系では閉鎖的に循環し、系外からの加入は少ない。屋久島は土壌生成年代が 7300 年と新しく、現在の表層土壌中に含まれるリンのほとんどが火山灰由来だと考えられる。Walker & Syers （1976）の土壌生成に伴うリンの形態変化のモデルによれば、土壌生成とともに、土壌中の全リン濃度や一次鉱物由来のカルシウム態リンは減少し、植物の利用しにくい吸蔵態リンは増加する。本研究では、土壌風化がより進むと思われる低標高ほど吸蔵態リンが増加したが、全リンは増加するという結果が得られた。さらに、火山灰供給時の形態として最も多いカルシウム態リンは土壌風化が進むと思われる低標高ほど多かった。これらの結果は Walker & Syers （1976）の示したモデルと異なり、温度と降水量が、風化と栄養塩の溶脱に複雑に影響し、現在の土壌リンの標高パターンが形成されている可能性が示唆された。
本研究の調査地における降水量は年間 3700-4800mm で標高との間に相関関係はなかった（R=-0.21 p=0.66）。高標高では降水が蒸発散量を上回り、土壌有機物の分解とともに酸素が消費されるため、より還元的な環境となる。さらに高標
高では土壌 pH が低いために、酸性で可溶化する一次鉱物のリン酸カルシウムが溶脱し、鉄やアルミニウム、さらにそれらに結合するリンの溶脱が促進されたと思われる。その結果、全リンも高標高ほど低下したのであろう。一方、ある程度の蒸発散量が見込まれる酸化的な低地では、全リンが維持されるとともに吸蔵態リンの生成が進んだと考えられる。
従って、温度と降水量の効果には複雑な関係が想定されるが、植物にとって可給性の高い無機態リン画分や土壌無機態
窒素濃度は低標高ほど高かった。これには温度の窒素無機化に対する直接的な影響と、リン可給性を介在した間接的な影響の 2 つが考えられる。今回はこれらの影響の分離はできなかった。
このように土壌中のリンと無機態窒素は、降水量よりも標高の影響を強く受けた結果、温度に応じて濃度勾配が形成されたと考えられる。これがリンと窒素の可給性を支配するために、森林のリン利用効率と窒素利用効率に大きな影響を及ぼす結果が得られたのであろう。このような土壌の影響が、植物への温度の直接的影響に加わり、屋久島の植生垂直分布が形成された可能性が示唆された。
キーワード: リン, 火山灰, 栄養塩利用効率, 気候, 土壌生成過程, 栄養塩循環
Keywords: Phosphorus, Volcanic Ash, Nutrient-use efficiency, Climate, Pedogenesis

1/1

MIS03-08

会場:104

時間:5 月 27 日 12:00-12:15

日本のアロフェン質黒ボク土に含まれる雲母の起源と放射性セシウム固定能に関する研究
Origin of mica in Allophanic Andosols in Japan and its role as a radiocesium fixing material
中尾 淳 1∗ ; 中尾 彩 2 ; 田中 亮吏 3 ; 矢内 純太 1
NAKAO, Atsushi1∗ ; NAKAO, Aya2 ; TANAKA, Ryoji3 ; YANAI, Junta1
1

京都府立大学大学院生命環境科学研究科, 2 京都府立大学生命環境学部, 3 岡山大学地球物質科学研究センター分析地球
化学部門
1
Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 2 Faculty of Life and Environmental Sciences, Kyoto Prefectural University, 3 Institute for Study of the Earth’s interior, Okayama University

The accident at the Fukushima Daiichi Nuclear Power Plant in March 2011 has turned attention to the fate of radiocesium(RCs) in soils in Japan. Allophanic Andosols are common soils in Japan, which generally have clay mineralogy rich in low crystalline minerals such as allophane and imogolite. Since RCs is not adsorbed strongly on these minerals, Allophanic Andosols are
assumed to have very low RCs retention ability. The objective of this study is to elucidate the relationship between RCs retention
ability and mineralogical properties of Allophanic Andosols in Japan. We hypothesized that trace amount of micas are deposited
as a loess component even in Allophanic Andosols, which control the RCs retention ability.
Twenty-three soil samples were collected from a plow layer (0-15 cm) of either paddy or upland fields distributing at alluvial
plains in Hokkaido, Tohoku, Kanto, and Kyusyu districts, representative areas of Allophanic Andosols. Particles with a size of
2-20 µm and <2.0 µm were fractionated from the soils by sedimentation method. RCs retention ability for each particle wasrepresented by the Radiocesium intereception potential (RIP). Quartz content was estimated by random powder X-ray diffraction
analysis for 2-20 µm particles with adding α-Al2 O3 as an internal standard. Mica content in 2-20 µm particles was estimated by
the amount of potassium extracted by fusion with NaHSO4 , whereas that in <2.0 µm particles was estimated by K extracted bydigestion with HF-HClO4 . Quartz was isolated from 2-20 µm particles by the selective dissolution with H2 SiF6 , and then δ 18 O
value for the isolated quartz was determined to estimate the origin.
The RIP value for 2-20 µm and <2 µm fractions was 1.7±0.8 mol kg−1 and 2.6±1.3 mol kg−1 , respectively. Mica-K content
in the respective fractions was 3.2±1.3 g kg−1 and 3.4±1.7 g kg−1 . These values are considerably small compared with thosefor fine particles in non-volcanic soils. The RIP positively correlated with mica-K content for each fraction, indicating that RCs
retention ability is mainly controlled by the amount of micas, in spite of its minority as a mineral component. The mica-K content
is proportional to the quartz content, suggesting that the origin of these minerals would be the same. Furthermore, δ 18 O value
for the isolated quartz was +14.8 ‰ on average with a range of +10.8 to +16.1 ‰, which is clearly higher than those of volcanic
materials while similar to those of Chinese loess. Thus, this study strongly indicated that the RCs retention ability of Allophanic
Andosols is largely controlled by loess-derived micas.
キーワード: 風成塵, 酸素同位体比, 放射性セシウム捕捉ポテンシャル, アロフェン質黒ボク土, 雲母
Keywords: loess, oxygen isotopic analysis, Radiocesium Interception Potential, Allophanic Andosol, mica

1/1

MIS03-09

会場:104

時間:5 月 27 日 14:15-14:30

森林流域の窒素飽和現象解明のための今日的なアプローチと戦略
Relevant approaches and strategies for investigation on the nitrogen saturation in forested
catchments
大手 信人 1∗ ; 磯部 一夫 2 ; 徳地 直子 1
OHTE, Nobuhito1∗ ; ISOBE, Kazuo2 ; TOKUCHI, Naoko1
11

京都大学, 2 東京大学
Kyoto University, 2 University of Tokyo

After the Industrial Revolution, global scale nitrogen (N) cycle has drastically been altered by increase of anthropogenic N
emissions to the atmosphere. Inorganic N concentration in atmosphere and their depositions reached unprecedented level in
Europe, northeast United States and northeast Asia. These have caused ”Nitrogen Saturation” in the forested areas within thehigh N deposition regions of Europe, North America, China and Japan. Mechanisms of nitrogen saturation have previously
been studied from biogeochemical point of view. N dynamics in catchment-scale, however, could not be described sufficiently,
because geographical variations of catchment characteristics such as climatic and hydrologic properties are generally large andtheir effects provide various aspects of responses in high nitrogen depositions. We propose new strategies based on multi-aspects
approach combining microbial ecology and catchment hydrology to reconstruct the mechanistic understandings on previously
reported ecosystem level biogeochemical responses to the environmental changes such as high N inputs. Combined applicationsof novel isotopic tracer techniques and newly advanced functional gene analysis onto the multiple forest landscapes will provide
us insightful information on spatiotemporal heterogeneity and non-linear responses of N dynamics related to the N saturation
phenomena in forest catchments.
キーワード: 森林流域, 窒素飽和, 微生物生態学, 同位体トレーサー, 水文課程
Keywords: forested catchment, nitrogen saturation, microbial ecology, isotope tracer, hydrological processes

1/1MIS03-10

会場:104

時間:5 月 27 日 14:30-14:45

メタトランスクリプトーム解析から見た水田土壌の炭素・窒素循環とそれを駆動する微生物
Carbon and nitrogen transformation and their driving microorganisms in paddy soil, asassessed by meta-transcriptomics
田伏 曜子 1∗ ; 伊藤 英臣 2 ; 白鳥 豊 3 ; 磯部 一夫 1 ; 大塚 重人 1 ; 妹尾 啓史 1
TABUSHI, Yoko1∗ ; ITOH, Hideomi2 ; SHIRATORI, Yutaka3 ; ISOBE, Kazuo1 ; OTSUKA, Shigeto1 ;SENOO, Keishi11

東京大学大学院農学生命科学研究科, 2 産業技術総合研究所 北海道センター, 3 新潟県農業総合研究所
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 2 National Institute of Advanced Industrial Scienceand Technology (AIST) Hokkaido, 3 Niigata Agricultural Research Institute1

水田土壌は水管理により大きな環境変動を受ける。土壌が湛水されると大気から土壌への酸素の供給が緩やかになり、日数の経過とともに表層において酸化層と還元層の分化が起こる。酸化層では好気的環境が維持されており、硝化・メ
タン酸化などの酸化反応が進行する。還元層は、土壌への酸素の供給速度よりも土壌中での消費速度が上回り、次第に酸素が枯渇して嫌気的な環境が形成される層である。この過程において、脱窒・マンガン還元・鉄還元・硫酸還元・メタ
ン生成といった異化的な還元反応が逐次的に進行する。主として微生物によって駆動されるこれらの酸化還元反応は土壌中の炭素・窒素などの物質循環に重要であり、土壌の肥沃度、水稲生育、地域・地球環境と深く関わっている。従って、水田土壌で活発な微生物群集や、物質循環に関わる機能遺伝子群の転写状況と多様性、それらの変遷を詳細に明らかにすることで、水稲生産性の維持向上や環境保全につながる基礎的知見が得られると期待される。
本研究では、水田から経時的に採取した酸化層・還元層それぞれの土壌について土壌 RNA の超大規模シーケンス解
析（メタトランスクリプトーム解析）を行った。rRNA 解析から各層において活発な微生物群集の構造と変動を、mRNA
解析から炭素・窒素循環に関わる機能遺伝子の転写量、持ち主と推定される微生物群とその変動を調べた。メタトラン
スクリプトーム解析から見えてきた水田土壌微生物と炭素・窒素循環について報告する。

キーワード: 土壌微生物群集, メタトランスクリプトーム, バイオインフォマティクス, 水田, 炭素窒素循環
Keywords: soil microbial communities, metatranscriptome, bioinformatics, paddy soil, CN cycle

1/1

MIS03-11

会場:104

時間:5 月 27 日 14:45-15:00

耕作放棄が生態系炭素プールに与える影響
Agricultural abandonment influences the ecosystem carbon pools
下田 星児 1∗ ; 和穎 朗太 2
SHIMODA, Seiji1∗ ; WAGAI, Rota2
1
1

農研機構 北海道農業研究センター芽室研究拠点, 2 農業環境技術研究所
NARO Hokkaido Agricultural Research Center Memuro, 2 National Institute for Agro-Environmental Sciences

Land abandonment, which is increasing globally, has significant impact on terrestrial carbon (C) budget, vegetation, andbiodiversity. Invasive alien plants often outcompete native plants after agricultural abandonment, which can lead to the alterationin ecosystem C and nutrient balance. Perennial plants have been an exceptionally successful invader in agricultural abandoned
fields around the world. Irrespective of soil nutrient status, alien plants rapidly dominates abandoned agricultural fields in thetemperate regions. While negative impact of alien plants on local and regional biodiversity is well established in conservation
ecology, its impact on C sequestration potential is much less studied. Paddy fields used for rice (Oryza sativa L.) production
are the dominant human land-use systems for a long time throughout Japan. Japan has increased to nearly 10% of the total
cultivated land area. The aim of the present study was to investigate how the rice paddy abandonment influenced the storage of
C in ecosystem components during the secondary succession over decadal time scale.
If paddy fields, the typical agricultural land in Japan, are left abandoned, the amount of soil C in the abandoned fields up to
20 years after being abandoned is lower than that of paddy fields under cultivation. If the field is abandoned for a long time, theamount of soil C increases due to organic matter from weeds, but it is considered that the process will take more than 20 years.
We hypothesize that the invasion of alien plants to the abandoned paddy fields enhances ecosystem C storage by their high N use
efficiency and high productivity. As results, the temporal change in soil C was similar among vegetation type through amount of
input C was similar in present study.

キーワード: 土地利用変化, 水田, 草原, 侵入, リター
Keywords: land use change, paddy, grassland, invasive alien plants, litter

1/1

MIS03-12

会場:104

時間:5 月 27 日 15:00-15:15

環境変化に対する土壌炭素応答：温暖化応答およびプライミング効果を例に
Responses of organic carbon in a variety of soils controlled by temperature and cellulose
supply
飯村 康夫 1∗
IIMURA, Yasuo1∗
11

滋賀県大環境科学
The University of Shiga Prefecture

Carbon stored in the upper meter of mineral soils is estimated to be 2500 Gt, which is approximately 3.3 times the size of theatmosphere and 4.5 times the size of the vegetation. Therefore, soil organic matter is often considered as a significant carbon
0
reservoir on the earth s surface. Although changes in soil organic carbon contents (by natural or anthropogenic causes) have asignificant impact on the global carbon cycle, the mechanisms of soil organic carbon stabilization and destabilization and thefactors controlling these mechanisms are not very well understood. We thus focused on the response of organic carbon in avariety of soils (black soil, brown soil, and red-yellow soil, etc.) controlled by temperature and fresh carbon (cellulose) supply.
In addition, we considered the factors controlling the temperature sensitivity and priming effect.

1/1

MIS03-13

会場:104

時間:5 月 27 日 15:15-15:30

比重分画法と安定同位体トレーサー法を用いた土壌有機物安定化プロセスの定量的解析：火山灰土壌と熱帯強風化土壌の比較
Organic matter stabilization in Andisol and Ultisol revealed by isotopic tracer experimentand density fractionation
早川 智恵 1∗ ; 和穎 朗太 2 ; 稲垣 善之 3 ; 浅野 眞希 2
HAYAKAWA, Chie1∗ ; WAGAI, Rota2 ; INAGAKI, Yoshiyuki3 ; ASANO, Maki2
1
1

東大院農, 2 農環研, 3 森林総研
Univ. Tokyo, 2 NIAES, 3 FFPRI

For predicting C cycling in terrestrial ecosystem, dynamics of organic matter (OM) in soil can be a large component that
increases uncertainty. Once OM is supplied into soil system mainly as plant detritus and root exudates, OM is decomposed by
microorganisms and a proportion of OM is stabilized through association with soil mineral particles. The OM in soils has a wide
range of size, density, and chemical reactivity. Organo-mineral particles of heavy-density fraction are highly resistant against
microbial degradation compared to mineral-free OM (i.e., plant detritus and low-density fraction). The high C sequestration
capacities of soils (e.g., Andisol) are hypothesized to be regulated by incorporation rates of microbial-processed OM into heavier
fraction. To test this hypothesis, we conducted incubation experiment using tracer to quantify the pool sizes, influx and efflux
rates, and mean residence times (MRTs) of different density classes.
Different types of soils were sampled from two agricultural lands; a volcanic-ash soil (Andisol) from Japan and a highlyweathered tropical soil (Ultisol) from Indonesia. The incubation experiments were carried out after addition of 13 C-labelled
glucose (99 13 C atom%, 0.1915 mmol 13 C g 1soil as solution) or 13 C, 15 N-labeled glutamic acid to the soils (2-mm sieved, 5 g
dry weight). The soils were incubated for 276 d at 30oC and 50% water holding capacity. After the incubation, soil was separated
into three fractions according to its density using sodium polytungstate as heavy liquid: low (<1.8 g cm−3 ), middle (1.8-2.25 g
cm−3 for Andisol, 1.8-2.5 g cm−3 for Ultisol), high (>2.25 g cm−3 for Andisol, >2.5 g cm−3 for Ultisol) density fractions. We
measured the mass, isotopic ratios (13 C/12 C, 15 N/14 N) and total C and N concentrations of the density fractions as well as theamount of CO2 respired during the incubation by alkali trap method. We also measured the specific surface areas (SSA) of soil
minerals and the concentrations of Al, Fe oxides/hydroxides.
For both soils, ca. 70 to 80 % of added 13 C were mineralized to CO2 within 1 month after substrate addition. The density
fractionation showed that 13C recovery in the low-density fraction was low (0.5 - 3.8%) throughout the incubation period.
The 13 C recovery within the mid- and high-density fractions was greater than 20%. This indicates that labile substrates wereimmediately incorporated into the mid- and high-density fractions through microbial processing in the both soils. The highest
13
C recovery was observed in the mid-density fraction of Andisol and in the high-density fraction of Ultisol, respectively. MRTsof 13 C in the density fractions positively correlated with SSAs for respective soil types. This can be explained by differences inmineralogy which contribute to OM stabilization through sorption; short-range-order minerals (e.g., allophane and imogolite) inAndisol and iron oxides in Ultisol, respectively. Our results support the hypothesis that newly-added OM is stabilized throughassociation of microbial metabolites with mineral particles. However, dominant density class and turnover of stabilized OM
could be variable depending on soil types and clay mineralogy with high specific surface areas.
Keywords: 13C-glucose, 13C, 15N-glutamic acid, Andisol, Ultisol, organo-mineral particle

1/1

MIS03-14

会場:104

時間:5 月 27 日 15:30-15:45

環境中におけるタンニンの構造と機能の変化
Changes in the structure and function of tannins in natural environments
眞家 永光 1∗
MAIE, Nagamitsu1∗
1
1

北里大学獣医学部
School of Veterinary Medicine, Kitasato University

Tannins are polyphenols that are contained in plants where they can account to 20% of the plant dry weight depending on its
species and organs. Tannins are known to bind to proteins, making insoluble complexes that are resistant to microbial degradation. While tannins are considered to play various roles in ecosystems, we are not fully understand the dynamics and functions oftannins in them. Here, I would like to present the changes in the structure and function of tannins in water and soil environments.
Furthermore, their possible influence on nitrogen cycling in mangrove ecosystems will be proposed.
Molecular structure and protein binding ability of CT changes during the decomposition of foliage (Maie et al. 2003)
Tannins are classified into two subgroups, condensed tannins (CT) and hydrolysable tannins (HT). CT are mixtures of polymers of flavan-3-ol units with different degrees of polymerization and mostly hydroxyl substitutions. Molecular structure of CT
in foliage changes during the decomposition of foliage. CT molecules composed of prodelphinidin unit (PD), which has morehydroxyl groups than procyanidin (PC), are more susceptible to structural changes. Structural change of CT accompanied withthe decrease of protein-binding ability.
Tannins are important source of DOM leached from litter, especially at the early stage of decomposition (Nishimura etal. 2012)
Dissolved organic matter (DOM) leached from litter may contain tannin-derived materials. Since tannins are water-soluble
and has wide structural variety among different species, DOM composition in leachate is most diverse at the early stage of the decomposition, but converge into relatively similar composition by time when lignin-degradation products become a major sourceof DOM.
Tannins-protein complex may contribute to nitrogen cycling in mangrove ecosystem, acting as a delayed release fertilizer (Maie et al., 2008)
Fate of CT leached into water environments can be variable. They may aggregate in saline water, adsorb to sediment, andcomplex with proteins. CT change their chemical structure quickly in water, becoming ”invisible” to analytical window. CTprotein complexes are refractory to microbial degradation, but photo-reactive. By exposing CT-protein complexes to sun light,
proteins can be released into water. In mangrove estuary, a large amount of tannins and proteins could be released into water in a
relatively short period when leaves fall into water. CT might be contributing to preserve N in mangrove ecosystem, by acting asa delayed release fertilizer.
References
Maie et al. 2003. Soil Biology & Biochemistry 35, 577-589.
Maie et al., 2008. Limnology & Oceanography 53, 160-171.
Nishimura et al. 2012 J. Environ. Quality 41, 823-833.
キーワード: 溶存有機物, 構造変化, タンパク質結合能, マングローブ湿地, 窒素サイクル, 森林生態系
Keywords: dissolved organic matter, forest ecosystem, mangrove estuary, nitrogen cycling, protein binding ability, structuralchange1/1

MIS03-15

会場:104

時間:5 月 27 日 15:45-16:00

シベリア永久凍土域におけるタイガ林の有機物層の生分解と養分供給ポテンシャル
Nutrient release during biodegradation of organic horizons in the Siberian taiga underlain
by continuous permafrost
川東 正幸 1∗ ; プロクシュキン アナトリ 2 ; 隅田 裕明 3
KAWAHIGASHI, Masayuki1∗ ; PROKUSHKIN, Anatoly2 ; SUMIDA, Hiroaki3
1

首都大学東京大学院 都市環境科学研究科, 2 ロシア科学アカデミースカチェフ森林研究所, 3 日本大学生物資源科学部
Graduate School of Urban Environmental Sciences, 2 Sukachev Institute of Forest, Rossia Academy of Science, 3 College of
Bioresource Sciences, Nihon University

1

Organic horizons under the Siberian taiga forest have a significant role of nutrient supply for plants through their biodegradation processes and of heat insulation for permafrost table underneath shallow mineral soil layer. Lower weathering stages ofmineral soils underlain by permafrost have lower potential of soil nutrient retention and release, indicating that summer growing
vegetation can expect to fill their nutrient requirements released by organic matter degradation. Decomposed organic matter can
supply mineral and biogenic nutrients to plants and microorganisms. Organic horizons often suffer from frequent forest fire in
the Siberian forest. Forest fire moves through organic horizon on the ground because of low tree density in the forest stands.
Relatively low burning temperature can leave organic residue on the forest ground. Ground temperature during forest fire is a
key variable for changes in properties of organic horizons. Solutes release potential and biodegradability of organic horizons
was evaluated in this study along with heating temperature gradient. To estimate the effect of forest fire on the biodegradation
processes of organic horizons, we prepared organic horizon samples heated between 65o C and 550o C under a relatively oxygen
limited atmospheric condition.
A sampling site located in the Evenkia province in the central Siberia. Soils are classified as Oxyaquic Cryosols or Gelic Cambisols according to the WRB classification system. Organic horizon samples were taken depending on hummock topography.
Air-dried and powdered samples were heated in a muffle furnace between 105 and 550o C for 15minites. Organic residues wereapplied to incubation experiment to evaluate biodegradation and solutes release. Biodegradation was evaluated from mineralization rates being calculated using temporal changes in CO2 concentration during an incubation experiment and total organiccarbon content in heated solid samples. During the same incubation time course, biogenic elements released from the heatedsamples were determined after water extraction by ICP-AES, Ion-chromatography and TOC-L with total nitrogen module unit.
Solutes release from heated organic horizon samples by water saturation was different between samples depending on theheating temperature. Larger amount of nutrient elements were released from organic horizons taken from trough points on thehummock. Samples heated at 250o C released the highest amount of solutes mainly dominated by dissolved organic C. Basic
cations and major anions including phosphate, nitrate and chloride were also largely released from the sample heated at 250o C.
Higher the heating temperature was, solutes concentration was lower. Solution pH was higher with increasing the heating temperature. The ratios of carbon to nitrogen in solid samples were decreased with increasing the heating temperature. The temperaturedependence of solutes release was different along with hummock topography.
The maximum mineralization (%) was approximately 4% of total C in samples heated at lower temperature below 180o C. The
mineralization rate was not largely different between samples, indicating that the biodegradation process in all heated samples
mainly depends on the amounts of easily decomposable carbon source, such as DOC. There are significant correlations between
the maximum mineralization rate and DOC or inorganic N. Solutes mainly consisting of nutrients and energy source for microorganisms can be a significant controlling factor for the biodegradation process of organic horizons. The difference in solutes
composition and the biodegradation were mainly depending on heating temperature of organic horizons. Heating temperatureduring a forest fire is an important parameter controlling the further degradation of organic matter in organic horizons and thefate of carbon dynamics in the boreal permafrost affected forest region.

キーワード: 森林火災, 生分解性, 連続永久凍土域, 植物栄養, 火災温度, 腐植物質
Keywords: Forest fire, Biodegradation, Continuous permafrost terrain, plant nutrition, burned temprature, humic substances

1/1

MIS03-16

会場:104

時間:5 月 27 日 16:15-16:30

アラスカ内陸部クロトウヒ林の土壌有機物の物理的組成と斜面内の変動
Variation in physical composition of soil organic matter in black spruce forests within aslope in Interior Alaska
鳥山 淳平 1∗ ; 田中 小田 あゆみ 1 ; 森下 智陽 1 ; 松浦 陽次郎 1 ; Hinzman Larry D.2
TORIYAMA, Jumpei1∗ ; TANAKA, Ayumi O.1 ; MORISHITA, Tomoaki1 ; MATSUURA, Yojiro1 ;HINZMAN, Larry D.2
1
1

森林総合研究所, 2 国際北極圏研究センター
Forestry and Forest Products Research Institute, 2 International Arctic Research CenterIn boreal region, rapid climate warming compared to lower latitude region can accelerate decomposition of soil organic matter(SOM) and, together with an increase in active layer depth, shift patterns of nutrient use and growth of boreal forests. In
discontinuous permafrost region of Interior Alaska, black spruce (Picea mariana ) grows in environments with various active
layer depths and different degree of nutrient limitation. These environmental gradients can also be obtained from different
positions in a single slope where climatic condition and fire history are similar. To clarify accumulation pattern of SOM and its
relationship to tree growth and slope position, we set a transect plot of 1.5km-long in black spruce forests in Caribou Poker Creek
Research Watershed. Tree growth rate at lower altitude (250 m) with shallow active layer in growing season is low compared tothat at higher altitude (450 m) with deep active layer. We collected samples from organic layers and mineral soil horizons in 14
soil profiles. The thickness of organic layer ranged 7 to 45 cm and was not correlated with altitude. Soil samples are separated
into light and heavy fractions by density fractionation approach. The light fraction of topsoil (surface horizon of mineral soil)
accounted for 269 g kg−1 of soil mass and 598 g kg−1 of soil organic carbon in average. The relationship between light fraction
content of topsoil and slope position was unclear. In the session, we focus on the 15 N natural abundance of SOM and othercomponents in the forest ecosystem and discuss the nitrogen cycling in black spruce forests with different growth rates.
キーワード: クロトウヒ, 土壌有機物, 比重分画
Keywords: black spruce, soil organic matter, density fractionation

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MIS03-17

会場:104

時間:5 月 27 日 16:30-16:45

永久凍土における有機物および養分循環の制御要因
Controls over turnover of organic matter and nutrients in permafrost soils
藤井 一至 1∗ ; 松浦 陽次郎 1 ; 藤井 創一郎 2 ; 稲垣 善之 1 ; 大澤 晃 2
FUJII, Kazumichi1∗ ; MATSUURA, Yojiro1 ; FUJII, Soichiro2 ; INAGAKI, Yoshiyuki1 ; OSAWA, Akira2
1
1

森林総合研究所, 2 京都大学農学研究科
Forestry and Forest Products Research Institute, 2 Graduate School of Agriculture, Kyoto University

Introduction: Plant productivity on permafrost soils is limited by nutrient supply from organic matter. Organic matter decomposition and nutrient release can be limited by cold climate, flooding, and recalcitrance of bryophytes (lichen and moss).
Plant-soil association (white spruce on mineral soil, black spruce on organic soil, and shrub tundra on lowland soil) suggests the
hypothesis that plant acquisition strategies for nutrient (esp., amino acids/inorganic N) can be matched by nutrient supply fromsoil organic matter. To test this, turnover of organic matter and nutrient release was investigated for three types of ecosystems in
Northwest Territory, Canada; white spruce forest (WSF) on the upland soil derived from glaciofluvial sands, black spruce forest(BSF) and tundra (TND) in lower position on fluvial sediments.
Methods: We measured soil organic carbon (SOC) storage [organic and mineral soil layers (0 to 30 cm)], soil temperatureand moisture, aeration index [Eh, free Fe oxides (oxalate-extractable Fe)] of soils, and the decomposition rates of litter (lichen,moss, and root litter) and cellulose filter paper buried in the soils. Regarding soil N dynamics, the concentrations of organicand inorganic N in soil solution (zero-tension lysimeter) were measured. Root uptake of dual-labeled (13 C, 15 N) glutamic acid,15
N-labeled ammonium, and 15 N-labeled nitrate was measured 24 h after spike of mixture solution.
Water dynamics: Episodic flooding events were observed following spring snowmelt at all sites. Rapid snowmelt and waterpercolation enhanced aeration in the sandy soil profile of WSF, while the BSF and TND soils were saturated by water flooding
on impermeable permafrost layer (30 cm deep) even in summer. The seasonal cycles of reducing- and oxidizing- conditions wererecorded as accumulation of free Fe oxides in the soils.
C dynamics: The C stocks in the organic and mineral soil layers were greater in TND (188 Mg C ha−1 ) and BSF (207-237
Mg C ha−1 ) than in WSF (37 Mg C ha−1 ). When the regression analysis was conducted for 15 soil profiles, there was a positive
correlation between SOC storage and free Fe oxide concentration. The high concentrations of free Fe oxides in soils appeared
to be an index of poor drainage and high SOC storage. Mass loss rates of cellulose filter paper, lichenous litter, and root litter
followed the order: WSF>TND>BSF. Water flooding and cold climate retarded decomposition of organic matter in BSF and
TND. The development of hummocky micro-topography, which was recorded as the tilting of drunken forest, resulted in accumulation of sparingly-decomposable lichen and moss debris in BSF. The warmer and aeration conditions in sandy upland soil of
WSF enhanced turnover of organic matter.
N dynamics: Dissolved organic N is abundant in soil solution at all sites. Nitrogen species in soil solution was dominated bynitrate and ammonium ions in TND soil, while it was ammonium in WSF and BSF soils. Regarding N uptake by plants, TND
plants (shrub birch and grasses) preferentially absorb inorganic N (ammonium and nitrate), while white spruce and black spruce
could also utilize amino acid-N. Both C and N of amino acids were assimilated by white spruce roots, while only ammonium
was transferred to roots of black spruce probably after rapid mineralization by mycorrhizae or roots. N preference of plants is
consistent with the dominant N species in soil solution.
Conclusions:Water flooding as well as cold climate retarded turnover of organic matter in black spruce forest. Despite slow
turnover of organic matter, black spruce can utilize amino acids as well as ammonium. In warmer and aerated sandy soil, white
spruce can absorb both amino acids and inorganic N. In the lowland tundra soil rich in inorganic N, plants can absorb inorganic
N. This highlights the importance of considering plant-soil association to predict responses of ”sensitive” ecosystem to futurechanges in flooding, fires, and climate.

キーワード: 永久凍土, 土壌有機物, 溶存有機物, アミノ酸, 微生物
Keywords: permafrost, soil organic matter, dissolved organic matter, amino acids, microorganism

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MIS03-18

会場:104

時間:5 月 27 日 16:45-17:00

土壌・生態系研究のこれからPossible future directions in soil and ecosystem research和穎 朗太 1∗ ; 小崎 隆 2
WAGAI, Rota1∗ ; KOSAKI, Takashi2
1
1

農業環境技術研究所, 2 首都大学東京
National Institute for Agro-Environmental Science, 2 Tokyo Metropolitan University

Better understanding of soil is fundamental to enhance sustainability of humankind, to conserve natural environment, and to
predict/manage future earth environment. Thus, soil scientists can and should play bigger role beyond the field of agriculturalscience and collaborate more with the scientists of other disciplines. We will discuss possible future directions that we could taketo better understand soil processes in earth system’s context.
キーワード: 土壌プロセス, 生物地球化学, 生態系, 生態学, 環境科学, 地球表層プロセス
Keywords: soil process, biogeochemistry, ecosystem, ecology, environmental science, earth surface processe

1/1

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

1/1

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

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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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