Summary of NIAES Research Projects
1. Experiments, research, and surveys
Medium-term targets(1) Priority research areas
In line with the Basic Plan for Agriculture, Forestry,
and Fisheries Research that sets forth research priorities
over the next 10 years under the Japanese government’s
Basic Plan for Food, Agriculture and Rural Areas, NIAES
will focus on the following four priority research areas:interactions between global environmental change andagriculture, mechanisms of variation in and ecological
function of agrobiodiversity, dynamics of agro-chemicals
and methods of reducing their risks in agro-environments,
and advancing agro-environment inventory.
We will also work with relevant research organizations
and international agencies to efficiently pursue researchon global environmental problems in line with prevailinginternational developments related to environmental
issues,and will further strengthen our ties with otheragriculture-related research agencies to efficiently pursue
joint research that leverages the research resources of all
such agencies.
We will pursue the research detailed in the Appendix
to achieve these objectives.
As a sub-bank of the Gene Bank Project for which
the National Institute of Agrobiological Sciences (NIAS)
serves as the Center Bank, we will also work closelywith the Center Bank to efficiently collect, preserve, andevaluate the characteristics of genetic resources.
(2) Responding to government needs
We will respond promptly to government needs
emerging in the medium-term target period, and conduct
required research and development.
Medium Term Plan
(1) Pursuit of priority research
We will place priority on advancing the researchdetailed in the Appendix.
We vow to do the following as we pursue thisresearch:i. We will work with relevant research organizations andinternational agencies to efficiently pursue researchin line with prevailing international developments
related to environmental issues.
ii. We will further strengthen our ties with otheragriculture-related research agencies to efficiently
pursue joint research that leverages the researchresources of all such agencies.
iii. As a sub-bank of the Gene Bank Project for which the

National Institute of Agrobiological Sciences (NIAS)
serves as the Center Bank, we will also work closelywith the Center Bank to efficiently collect, preserve,
and evaluate the characteristics of genetic resources.
(2) Responding to government needs
We will respond promptly to government needs
emerging in the medium-term target period, and conduct
required research and development.
Pursuit of priority research
1. Interactions between global environmental change
and agriculture
Medium-term targets
Effecting major reductions in greenhouse gases(GHGs) as a means of combating global warming will in
the agricultural sector require the comprehensive pursuitof research and development to address global warming,
including the development of technologies for preserving
and reinforcing GHG emission reduction and absorptionfunctions, environmental forecasting technologies, andtechnologies for adapting to global warming.
We will accordingly conduct basic research on thequantitative assessment of global warming mitigation
measures in agriculture and elucidation of mechanisms
by which crops respond to global warming and otherenvironmental change, and research on forecasting
impacts.
(1) Quantification of mitigation options for GHG
emissions from agricultural lands
We aim to decipher the processes involved in soil
carbon storage and GHG emission, and conduct lifecycle
analyses on GHGs over the whole crop production
process so as to enable accurate quantitative assessmentsof global warming mitigation measures to serve as a basis
for developing comprehensive global warming mitigation
technologies.
(2) Mechanisms and impacts of global environmental
change on crop production
To accurately forecast the impacts of an increasingly
warm environment on crop production, we will elucidate
the mechanisms by which crops respond to risingtemperatures and CO2 levels; develop mathematicalmodels for assessing future adaptation measures suchas modification of cropping seasons and production
locations; and develop methods for assessing thevulnerability of a region to climate change in Japan andother Asian countries as well as for predicting changes inResearch Overview in FY2013
food production volume in response to such a change.
Medium Term Plan
(1) Quantification of mitigation options for GHG
emissions from agricultural lands
We will quantitatively assess comprehensive global
warming mitigation measures in order to effectively andefficiently implement such measures for farmland underinternational frameworks for addressing climate change
in 2013 and thereafter.
Specifically, we aim to decipher the processes
involved in soil carbon storage and greenhouse gas GHG
emissions, proceeding from test plots and laboratory
experiments to farmland, and will also use newly acquired
observational data and improve models that forecast
carbon storage and GHG emissions.
In addition to these models, we will gather andleverage fertilizer management, land use and other activity
level data to further refine forecasts of methane (CH4) andnitrous oxide (N2O) emissions from Japan’s farmlands
as well as forecasts of fluctuations in the amount of soil
carbon storage.
Furthermore, we will devise future farmland
management options that take into consideration factors
such as tradeoff relationships, the amounts of organic
resources available for use, and lifecycle assessments ofoverall crop production processes, and then quantitatively
assess the amounts of GHG emissions that could beachieved by means of comprehensive global warming
mitigation measures based on those options.
Additionally, we will use the information databases
and monitoring networks for GHG emissions and otherinformation in the monsoon Asia region to assess the
mitigation potential of global warming mitigation
measures if they are applied in this region.
(2) Mechanisms and impacts of global environmental
change on crop production
To aid in the development of rice cultivars andcultivation management techniques suited to the high CO2
concentrations and warmer environments predicted for the
future, we aim to determine the response characteristics
of rice plants to high CO2 concentrations and theirmechanisms of tolerance to high temperatures, and todevelop an impact prediction model.
Additionally, we aim to develop methods for assessing
the vulnerability of a region to climate change in Japanand other Asian countries, as well as for predictingchanges in food production volume in in response to sucha change.
We will use environmental manipulation experiments
such as Free-Air CO2 Enrichment (FACE) and chamber
experiments to determine, on the individual plant leveland on the community level, how responses by rice

plants to increased CO2 concentrations differ dependingon genetic type and cultivation environment, and to
experimentally elucidate the tolerance mechanisms of rice
plants to the high-temperature stress that is likely to occur
more frequently in the future.
Based on our findings, we will develop a model toforecast crop growth, yield, and quality in the futureenvironment predicted by climate scenarios in order toassess the effectiveness of techniques for adapting to
global environmental change.
Additionally, we will develop a model that forecasts
food production volume nationally for Japan and for
Monsoon Asia as a whole, taking into account climatechange and the technologies to adapt to it, based on
downscaling techniques for climate model calculation
results and on the outcomes of regional yield change
forecasting and research on environmental response
mechanisms of crops at the level of individual fields.
Furthermore, we will develop methods of assessing,according to region, the vulnerability of food production
capacity to climate change over the medium to longterm, taking into consideration the frequent occurrenceof extreme weather predicted in climate scenarios by theIntergovernmental Panel on Climate Change (IPCC) andothers, as well as changes in water resources and landuse.
Research Overview(1) Quantification of mitigation options for GHG
emissions from agricultural lands
Research background
The rapid increase in human activities in recent years
has resulted in a rise in the atmospheric concentrations ofCO2, CH4, N2O and other GHGs that are causing global
warming. Farmland and agriculture are also sourcesof GHGs, with paddy fields, the digestive activities ofruminants, livestock manure, and application of nitrogen
fertilizer considered as major sources of methane andnitrous oxide in particular. Given these circumstances,measures to combat global warming are of increasing
importance, and NIAES can contribute by assessing
volumes of GHGs generated and helping to reduce theiremission. Carbon accumulation in farmland soil throughthe addition of compost and other organic matter is seen
as a promising method of combating global warming.
Our research in this area focuses particularly on
elucidating the mechanisms of carbon accumulation and
GHG generation in farmland, developing technologies forcurbing GHG generation, and assessing and predicting thevolume of GHGs generated by agricultural activities.
Key results
i. Wide-Area, General Assessments of Change in Soil

Carbon and Emissions of Methane and Nitrous Oxide
For nationwide calculation of cropland soil carbonchange using the RothC soil carbon dynamics model,
we assessed the uncertainty arising from the addition oforganic matter to soil. We found that although the effecton soil carbon content is not large, there is a large effect on
the change in soil carbon that is calculated by deducting
the organic matter, and on the net–net absorption under
the Kyoto Protocol amount by deducting it. This shows
the importance of refining these estimates.
For the assessment of uncertainty in methane
emissions, we assumed a normal distribution withaverage values and standard deviation in a fundamental
soil environment study on soil physical and chemical
properties (SOC, pH, reducible Fe, bulk density, clay
content, and field moisture capacity) for gray lowland soil
rice paddies in southern Ibaraki Prefecture, and randomly
created a data set of 4000 data points. We entered thesedata into DNDC (DeNitrification–DeComposition)-Rice,
which predicts the amount of methane generated by ricepaddies, calculated methane emissions, and assessed theuncertainty caused by non-uniformity of soil physicaland chemical properties. We obtained a distribution very
similar to a gamma distribution because the methane
emission frequency distribution was highly dependent on
field moisture capacity.
ii. Modeling Based on Elucidating Soil Organic
Matter Dynamics and Greenhouse Gas Emission
Mechanisms, and Development of Global Warming
Mitigation Technologies
Using data from observations on cropland, we
validated a statistical model that predicts nitrous oxide(N2O) emissions from the amount of organic matterdecomposition, the soil C/N ratio calculated with the
RothC soil carbon dynamics model, and from the amountof chemical fertilizer nitrogen applied. On the whole,estimates of annual N2O emissions for the chemicalfertilizer plot and the cattle manure compost plot
coincided with measurements. This will enable widearea assessments using models that also incorporate theemission mechanism for N2O, along with soil carbon andmethane, thereby virtually completing preparations for
conducting nationwide assessments based on common
scenarios.
We were also the first in the world to find that, bydispersing andosol surface layer aggregates by using
different ultrasonic energy levels, and then fractionating
soil particles by size and assessing their characteristics,
the aggregates of andosols too have a hierarchicalstructure (Figure 1-1). The high carbon storage capacityof andosols is likely closely related to the characteristic
aggregate structure that we determined in this study.
iii. Assessment of climate change mitigation potential in
the monsoon Asia region
In an assessment of mitigation measures in Monsoon
Asia, we used experimental data from water-conserving
rice paddies with plastic mulch in China’s Sichuan
Province to calibrate both rice plant growth in the DNDC
(DeNitrification–DeComposition)-Rice model, and theparameters for the ground temperature increase andoxygen-blocking effects of the mulch. Measured andcalculated methane emissions in rice paddies with plastic
mulch were very similar. In addition to continuing a
project in Thai rain-fed paddies, we also launched a new

微細粒子

ミクロ・マクロ団粒（超音波耐性の有機無機集合体）

接着材

(a)

<2μｍ画分 (b)0.5 um(c)
2-53μｍ画分

5 um

53-4000 μｍ画分
（超音波なし）150 umFigure 1-1 Overview of Andosol Aggregate Structure.
Strong microparticles that do not break apart even under ultrasonic treatment (left and center) function as an adhesive that binds othersoil constituents (plant residue and sand particles) to form micro- and macro-aggregates (right). Scanning electron micrographs are,from left, (a) < 2 µm diameter, (b) microparticles 2–53 µm in size, and (c) aggregates before ultrasonic treatment. The particles in (a)are smaller than a single bacterium (about 1 µm), and the particles in (c) are at least 100 times the size of a bacterium.

Research Overview in FY2013
project to determine the effects of water-saving cultivationin irrigated paddies in four Southeast Asian countries.
(2) Mechanisms and impacts of global environmental
change on crop production
a. Understanding the mechanism of crop response to
climate change, and predicting impacts
Research backgroundAtmospheric CO2 concentration has risen by over
100 ppm since the Industrial Revolution when it stood at
about 280 ppm. Even if measures are taken to reduce CO2
emissions, atmospheric CO2 concentration is predicted tocontinue rising to 470–570 ppm by around 2050, and to
540–970 ppm by the end of the century. This rise in CO2
concentration is not only a cause of global environmental
change, including global warming and changes in water
resource circulation, but in itself also impacts crop
photosynthesis and water usage. The impacts of thepredicted rise in temperature and change in precipitation
volume and patterns on crops will also become evident inhigh CO2 environments (hereafter high CO2). The responseof crops and other plants to high CO2 will furthermore
greatly affect ecosystem carbon circulation. In order topredict such impacts of climate change and develop global
warming mitigation and adaptation technologies, it isnecessary to understand how crops and farmland material
cycles are affected by climate change, and to what extent
these impacts differ according to cultivars and cultivation
management methods.
To aid in the development of rice cultivars andcultivation management techniques suited to the highCO2 and high-temperature environments predicted forthe future, we will conduct environmental manipulation
experiments that utilize the Free-Air CO2 Enrichment(FACE) experimental facility or chambers to determine
how responses to increases in CO2 concentration andtemperature vary according to cultivar and cultivation
management method. We will also develop a model toforecast crop growth, yield, and quality in order to assess
the efficacy of techniques for adapting to environmental
change.
Key results
i. Search for promising characteristics for enhancing
production functions under high CO2 and warmer
temperature conditions
At the Tsukubamirai FACE (Free-Air CO2
Enrichment) experimental facility, we investigated leaf
blade photosynthesis and its related traits at various
growth stages in both the high yielding Indica cultivar“Takanari”, which has high yields even under conditionsof high CO2 concentration, and the standard Japonica
cultivar “Koshihikari”. We found that although high10

CO2 concentrations stimulated photosynthesis in both
cultivars, the stimulation of Takanari was far greaterthan that of Koshihikari at every growth stage (Figure1-2). To find the reason, we investigated stomatal
conductance (an indicator of stomatal aperture) and leaf
blade nitrogen and rubisco (an enzyme that catalyzes theCO2 fixation reaction in photosynthesis): we found thatboth are maintained at high levels in Takanari, whosehigh yields we attribute to the large amount of CO2 taken
into chloroplasts and the high CO2 fixation capacity in thechloroplast interior (Figure 1-3). These findings will be
useful in the development of high-yield cultivars to use
under future conditions of high CO2 concentrations.
ii. Elucidation of environmental stress mechanisms
caused by climate change, and development ofprediction techniques
To predict rice spikelet sterility caused by hightemperature, we developed a high temperature exposure
prediction model that takes flowering time distribution into
account; we used this model to assess the effectivenessof high temperature avoidance characteristics. Thereare expectations that this model will be useful for not
only forecasting the occurrence of sterility, but also forassessing cultivar characteristics that contribute to hightemperature avoidance. For example, in recent years
attention has been focused on early-morning floweringcharacteristics for avoiding high-temperature time
periods, but the effectiveness of introducing this trait has
yet to be adequately assessed. We therefore analyzed theextent to which glumous flower temperature at flowering
time changes by the introduction of the early-morning
flowering trait in India (Punjab) and China (Nanjing),

Figure 1-2

High-CO2 response of photosynthesis
rate in uppermost leaves of Takanari andKoshihikari raised in a FACE experiment.

FACE group CO2 concentration is 200 ppm higher than that of
the control group.
*** significant difference between cultivars at the 0.1% level.

which have very different climatic environments. Our
study found that with ordinary cultivars there is no large
difference between the two locations in terms of glumous
flower temperature at flowering time, but that glumous
flower temperature distribution when the early-morning
flowering trait had been introduced was clearly lower inIndia. In this and other ways, it was quantitatively shownthat cultivar-improvement effects are manifested very
differently depending on geographical region.
iii. The impacts of climate change on the dynamics ofcarbon and nitrogen in paddy fields
In an experiment that raised water temperature 2°C
under the high-CO2 conditions (200 ppm higher thannow) assumed for about 50 years in the future, we foundthat rice plants absorb much nitrogen under conditions ofglobal warming, but that in the latter period of growth,leaf blade nitrogen declines and high CO2 concentration
stimulates photosynthesis less (Figure 1-4). This findingis useful for forecasting rice plant growth and yield
responses under future climate change.

Uncertainty is supposed to be indicated whenassessing climate change impacts, but because uncertainty
until now has stemmed mainly from the range of climate
forecast values, assessments of uncertainty arising in cropmodels have been limited. We compared 13 world rice
plant models in the Agricultural Model Intercomparisonand Improvement Project (AgMIP): in forecasts foraround the year 2050, we found that the range of yield
forecasts deriving from differences among crop models
is wider than the range arising from differences among
climate models, and that forecast uncertainty is caused

iv. Elucidation of actual climate change impacts anddevelopment of impact prediction methods

Figure 1-4

Figure 1-3

Route by which Takanari’s high stomatal
conductance and leaf blade nitrogencontent increase photosynthesis.

Takanari has a large stomatal aperture at all CO2 concentrations
and its nitrogen nutrition is well maintained during the ripening
period. Therefore it appears that the main processes of its Calvincycle reactions are rapid, thus leading to a high photosynthesis
rate.

Leaf blade photosynthesis rate during the
mid-ripening period. (a) Rubisco content,(b) crop nitrogen absorption, and (c)distribution to leaf blades

When matching the CO2 concentrations (580 ppm) in smallchambers, the photosynthetic rates of rice plants raised underhigh-CO2 (FACE) and elevated-temperature conditions were on
average 23% lower than those for plants raised under control(current real-world) CO2 and non-elevated temperature levels (a).
There is a connection between this and the decline of rubisco,
the most important enzyme for photosynthesis, in the FACE
elevated-temperature group during the mid-ripening period (b).
Elevated temperature increased nitrogen absorption until the
mid-ripening period (c), but in the FACE elevated-temperaturegroup the proportion of nitrogen distributed to leaf blades waslow (d), which we believe to have caused the decreases in leafblade nitrogen and rubisco. Values for all groups are two-year
averages. **, *, and † indicate significance at 1%, 5%, and 10%
levels.

11

Summary of NIAES Research Projects
1. Experiments, research, and surveys
Medium-term targets(1) Priority research areas
In line with the Basic Plan for Agriculture, Forestry,
and Fisheries Research that sets forth research priorities
over the next 10 years under the Japanese government’s
Basic Plan for Food, Agriculture and Rural Areas, NIAES
will focus on the following four priority research areas:interactions between global environmental change andagriculture, mechanisms of variation in and ecological
function of agrobiodiversity, dynamics of agro-chemicals
and methods of reducing their risks in agro-environments,
and advancing agro-environment inventory.
We will also work with relevant research organizations
and international agencies to efficiently pursue researchon global environmental problems in line with prevailinginternational developments related to environmental
issues,and will further strengthen our ties with otheragriculture-related research agencies to efficiently pursue
joint research that leverages the research resources of all
such agencies.
We will pursue the research detailed in the Appendix
to achieve these objectives.
As a sub-bank of the Gene Bank Project for which
the National Institute of Agrobiological Sciences (NIAS)
serves as the Center Bank, we will also work closelywith the Center Bank to efficiently collect, preserve, andevaluate the characteristics of genetic resources.
(2) Responding to government needs
We will respond promptly to government needs
emerging in the medium-term target period, and conduct
required research and development.
Medium Term Plan
(1) Pursuit of priority research
We will place priority on advancing the researchdetailed in the Appendix.
We vow to do the following as we pursue thisresearch:i. We will work with relevant research organizations andinternational agencies to efficiently pursue researchin line with prevailing international developments
related to environmental issues.
ii. We will further strengthen our ties with otheragriculture-related research agencies to efficiently
pursue joint research that leverages the researchresources of all such agencies.
iii. As a sub-bank of the Gene Bank Project for which the

National Institute of Agrobiological Sciences (NIAS)
serves as the Center Bank, we will also work closelywith the Center Bank to efficiently collect, preserve,
and evaluate the characteristics of genetic resources.
(2) Responding to government needs
We will respond promptly to government needs
emerging in the medium-term target period, and conduct
required research and development.
Pursuit of priority research
1. Interactions between global environmental change
and agriculture
Medium-term targets
Effecting major reductions in greenhouse gases(GHGs) as a means of combating global warming will in
the agricultural sector require the comprehensive pursuitof research and development to address global warming,
including the development of technologies for preserving
and reinforcing GHG emission reduction and absorptionfunctions, environmental forecasting technologies, andtechnologies for adapting to global warming.
We will accordingly conduct basic research on thequantitative assessment of global warming mitigation
measures in agriculture and elucidation of mechanisms
by which crops respond to global warming and otherenvironmental change, and research on forecasting
impacts.
(1) Quantification of mitigation options for GHG
emissions from agricultural lands
We aim to decipher the processes involved in soil
carbon storage and GHG emission, and conduct lifecycle
analyses on GHGs over the whole crop production
process so as to enable accurate quantitative assessmentsof global warming mitigation measures to serve as a basis
for developing comprehensive global warming mitigation
technologies.
(2) Mechanisms and impacts of global environmental
change on crop production
To accurately forecast the impacts of an increasingly
warm environment on crop production, we will elucidate
the mechanisms by which crops respond to risingtemperatures and CO2 levels; develop mathematicalmodels for assessing future adaptation measures suchas modification of cropping seasons and production
locations; and develop methods for assessing thevulnerability of a region to climate change in Japan andother Asian countries as well as for predicting changes inResearch Overview in FY2013
food production volume in response to such a change.
Medium Term Plan
(1) Quantification of mitigation options for GHG
emissions from agricultural lands
We will quantitatively assess comprehensive global
warming mitigation measures in order to effectively andefficiently implement such measures for farmland underinternational frameworks for addressing climate change
in 2013 and thereafter.
Specifically, we aim to decipher the processes
involved in soil carbon storage and greenhouse gas GHG
emissions, proceeding from test plots and laboratory
experiments to farmland, and will also use newly acquired
observational data and improve models that forecast
carbon storage and GHG emissions.
In addition to these models, we will gather andleverage fertilizer management, land use and other activity
level data to further refine forecasts of methane (CH4) andnitrous oxide (N2O) emissions from Japan’s farmlands
as well as forecasts of fluctuations in the amount of soil
carbon storage.
Furthermore, we will devise future farmland
management options that take into consideration factors
such as tradeoff relationships, the amounts of organic
resources available for use, and lifecycle assessments ofoverall crop production processes, and then quantitatively
assess the amounts of GHG emissions that could beachieved by means of comprehensive global warming
mitigation measures based on those options.
Additionally, we will use the information databases
and monitoring networks for GHG emissions and otherinformation in the monsoon Asia region to assess the
mitigation potential of global warming mitigation
measures if they are applied in this region.
(2) Mechanisms and impacts of global environmental
change on crop production
To aid in the development of rice cultivars andcultivation management techniques suited to the high CO2
concentrations and warmer environments predicted for the
future, we aim to determine the response characteristics
of rice plants to high CO2 concentrations and theirmechanisms of tolerance to high temperatures, and todevelop an impact prediction model.
Additionally, we aim to develop methods for assessing
the vulnerability of a region to climate change in Japanand other Asian countries, as well as for predictingchanges in food production volume in in response to sucha change.
We will use environmental manipulation experiments
such as Free-Air CO2 Enrichment (FACE) and chamber
experiments to determine, on the individual plant leveland on the community level, how responses by rice

plants to increased CO2 concentrations differ dependingon genetic type and cultivation environment, and to
experimentally elucidate the tolerance mechanisms of rice
plants to the high-temperature stress that is likely to occur
more frequently in the future.
Based on our findings, we will develop a model toforecast crop growth, yield, and quality in the futureenvironment predicted by climate scenarios in order toassess the effectiveness of techniques for adapting to
global environmental change.
Additionally, we will develop a model that forecasts
food production volume nationally for Japan and for
Monsoon Asia as a whole, taking into account climatechange and the technologies to adapt to it, based on
downscaling techniques for climate model calculation
results and on the outcomes of regional yield change
forecasting and research on environmental response
mechanisms of crops at the level of individual fields.
Furthermore, we will develop methods of assessing,according to region, the vulnerability of food production
capacity to climate change over the medium to longterm, taking into consideration the frequent occurrenceof extreme weather predicted in climate scenarios by theIntergovernmental Panel on Climate Change (IPCC) andothers, as well as changes in water resources and landuse.
Research Overview(1) Quantification of mitigation options for GHG
emissions from agricultural lands
Research background
The rapid increase in human activities in recent years
has resulted in a rise in the atmospheric concentrations ofCO2, CH4, N2O and other GHGs that are causing global
warming. Farmland and agriculture are also sourcesof GHGs, with paddy fields, the digestive activities ofruminants, livestock manure, and application of nitrogen
fertilizer considered as major sources of methane andnitrous oxide in particular. Given these circumstances,measures to combat global warming are of increasing
importance, and NIAES can contribute by assessing
volumes of GHGs generated and helping to reduce theiremission. Carbon accumulation in farmland soil throughthe addition of compost and other organic matter is seen
as a promising method of combating global warming.
Our research in this area focuses particularly on
elucidating the mechanisms of carbon accumulation and
GHG generation in farmland, developing technologies forcurbing GHG generation, and assessing and predicting thevolume of GHGs generated by agricultural activities.
Key results
i. Wide-Area, General Assessments of Change in Soil

Carbon and Emissions of Methane and Nitrous Oxide
For nationwide calculation of cropland soil carbonchange using the RothC soil carbon dynamics model,
we assessed the uncertainty arising from the addition oforganic matter to soil. We found that although the effecton soil carbon content is not large, there is a large effect on
the change in soil carbon that is calculated by deducting
the organic matter, and on the net–net absorption under
the Kyoto Protocol amount by deducting it. This shows
the importance of refining these estimates.
For the assessment of uncertainty in methane
emissions, we assumed a normal distribution withaverage values and standard deviation in a fundamental
soil environment study on soil physical and chemical
properties (SOC, pH, reducible Fe, bulk density, clay
content, and field moisture capacity) for gray lowland soil
rice paddies in southern Ibaraki Prefecture, and randomly
created a data set of 4000 data points. We entered thesedata into DNDC (DeNitrification–DeComposition)-Rice,
which predicts the amount of methane generated by ricepaddies, calculated methane emissions, and assessed theuncertainty caused by non-uniformity of soil physicaland chemical properties. We obtained a distribution very
similar to a gamma distribution because the methane
emission frequency distribution was highly dependent on
field moisture capacity.
ii. Modeling Based on Elucidating Soil Organic
Matter Dynamics and Greenhouse Gas Emission
Mechanisms, and Development of Global Warming
Mitigation Technologies
Using data from observations on cropland, we
validated a statistical model that predicts nitrous oxide(N2O) emissions from the amount of organic matterdecomposition, the soil C/N ratio calculated with the
RothC soil carbon dynamics model, and from the amountof chemical fertilizer nitrogen applied. On the whole,estimates of annual N2O emissions for the chemicalfertilizer plot and the cattle manure compost plot
coincided with measurements. This will enable widearea assessments using models that also incorporate theemission mechanism for N2O, along with soil carbon andmethane, thereby virtually completing preparations for
conducting nationwide assessments based on common
scenarios.
We were also the first in the world to find that, bydispersing andosol surface layer aggregates by using
different ultrasonic energy levels, and then fractionating
soil particles by size and assessing their characteristics,
the aggregates of andosols too have a hierarchicalstructure (Figure 1-1). The high carbon storage capacityof andosols is likely closely related to the characteristic
aggregate structure that we determined in this study.
iii. Assessment of climate change mitigation potential in
the monsoon Asia region
In an assessment of mitigation measures in Monsoon
Asia, we used experimental data from water-conserving
rice paddies with plastic mulch in China’s Sichuan
Province to calibrate both rice plant growth in the DNDC
(DeNitrification–DeComposition)-Rice model, and theparameters for the ground temperature increase andoxygen-blocking effects of the mulch. Measured andcalculated methane emissions in rice paddies with plastic
mulch were very similar. In addition to continuing a
project in Thai rain-fed paddies, we also launched a new

微細粒子

ミクロ・マクロ団粒（超音波耐性の有機無機集合体）

接着材

(a)

<2μｍ画分 (b)0.5 um(c)
2-53μｍ画分

5 um

53-4000 μｍ画分
（超音波なし）150 umFigure 1-1 Overview of Andosol Aggregate Structure.
Strong microparticles that do not break apart even under ultrasonic treatment (left and center) function as an adhesive that binds othersoil constituents (plant residue and sand particles) to form micro- and macro-aggregates (right). Scanning electron micrographs are,from left, (a) < 2 µm diameter, (b) microparticles 2–53 µm in size, and (c) aggregates before ultrasonic treatment. The particles in (a)are smaller than a single bacterium (about 1 µm), and the particles in (c) are at least 100 times the size of a bacterium.

Research Overview in FY2013
project to determine the effects of water-saving cultivationin irrigated paddies in four Southeast Asian countries.
(2) Mechanisms and impacts of global environmental
change on crop production
a. Understanding the mechanism of crop response to
climate change, and predicting impacts
Research backgroundAtmospheric CO2 concentration has risen by over
100 ppm since the Industrial Revolution when it stood at
about 280 ppm. Even if measures are taken to reduce CO2
emissions, atmospheric CO2 concentration is predicted tocontinue rising to 470–570 ppm by around 2050, and to
540–970 ppm by the end of the century. This rise in CO2
concentration is not only a cause of global environmental
change, including global warming and changes in water
resource circulation, but in itself also impacts crop
photosynthesis and water usage. The impacts of thepredicted rise in temperature and change in precipitation
volume and patterns on crops will also become evident inhigh CO2 environments (hereafter high CO2). The responseof crops and other plants to high CO2 will furthermore
greatly affect ecosystem carbon circulation. In order topredict such impacts of climate change and develop global
warming mitigation and adaptation technologies, it isnecessary to understand how crops and farmland material
cycles are affected by climate change, and to what extent
these impacts differ according to cultivars and cultivation
management methods.
To aid in the development of rice cultivars andcultivation management techniques suited to the highCO2 and high-temperature environments predicted forthe future, we will conduct environmental manipulation
experiments that utilize the Free-Air CO2 Enrichment(FACE) experimental facility or chambers to determine
how responses to increases in CO2 concentration andtemperature vary according to cultivar and cultivation
management method. We will also develop a model toforecast crop growth, yield, and quality in order to assess
the efficacy of techniques for adapting to environmental
change.
Key results
i. Search for promising characteristics for enhancing
production functions under high CO2 and warmer
temperature conditions
At the Tsukubamirai FACE (Free-Air CO2
Enrichment) experimental facility, we investigated leaf
blade photosynthesis and its related traits at various
growth stages in both the high yielding Indica cultivar“Takanari”, which has high yields even under conditionsof high CO2 concentration, and the standard Japonica
cultivar “Koshihikari”. We found that although high10

CO2 concentrations stimulated photosynthesis in both
cultivars, the stimulation of Takanari was far greaterthan that of Koshihikari at every growth stage (Figure1-2). To find the reason, we investigated stomatal
conductance (an indicator of stomatal aperture) and leaf
blade nitrogen and rubisco (an enzyme that catalyzes theCO2 fixation reaction in photosynthesis): we found thatboth are maintained at high levels in Takanari, whosehigh yields we attribute to the large amount of CO2 taken
into chloroplasts and the high CO2 fixation capacity in thechloroplast interior (Figure 1-3). These findings will be
useful in the development of high-yield cultivars to use
under future conditions of high CO2 concentrations.
ii. Elucidation of environmental stress mechanisms
caused by climate change, and development ofprediction techniques
To predict rice spikelet sterility caused by hightemperature, we developed a high temperature exposure
prediction model that takes flowering time distribution into
account; we used this model to assess the effectivenessof high temperature avoidance characteristics. Thereare expectations that this model will be useful for not
only forecasting the occurrence of sterility, but also forassessing cultivar characteristics that contribute to hightemperature avoidance. For example, in recent years
attention has been focused on early-morning floweringcharacteristics for avoiding high-temperature time
periods, but the effectiveness of introducing this trait has
yet to be adequately assessed. We therefore analyzed theextent to which glumous flower temperature at flowering
time changes by the introduction of the early-morning
flowering trait in India (Punjab) and China (Nanjing),

Figure 1-2

High-CO2 response of photosynthesis
rate in uppermost leaves of Takanari andKoshihikari raised in a FACE experiment.

FACE group CO2 concentration is 200 ppm higher than that of
the control group.
*** significant difference between cultivars at the 0.1% level.

which have very different climatic environments. Our
study found that with ordinary cultivars there is no large
difference between the two locations in terms of glumous
flower temperature at flowering time, but that glumous
flower temperature distribution when the early-morning
flowering trait had been introduced was clearly lower inIndia. In this and other ways, it was quantitatively shownthat cultivar-improvement effects are manifested very
differently depending on geographical region.
iii. The impacts of climate change on the dynamics ofcarbon and nitrogen in paddy fields
In an experiment that raised water temperature 2°C
under the high-CO2 conditions (200 ppm higher thannow) assumed for about 50 years in the future, we foundthat rice plants absorb much nitrogen under conditions ofglobal warming, but that in the latter period of growth,leaf blade nitrogen declines and high CO2 concentration
stimulates photosynthesis less (Figure 1-4). This findingis useful for forecasting rice plant growth and yield
responses under future climate change.

Uncertainty is supposed to be indicated whenassessing climate change impacts, but because uncertainty
until now has stemmed mainly from the range of climate
forecast values, assessments of uncertainty arising in cropmodels have been limited. We compared 13 world rice
plant models in the Agricultural Model Intercomparisonand Improvement Project (AgMIP): in forecasts foraround the year 2050, we found that the range of yield
forecasts deriving from differences among crop models
is wider than the range arising from differences among
climate models, and that forecast uncertainty is caused

iv. Elucidation of actual climate change impacts anddevelopment of impact prediction methods

Figure 1-4

Figure 1-3

Route by which Takanari’s high stomatal
conductance and leaf blade nitrogencontent increase photosynthesis.

Takanari has a large stomatal aperture at all CO2 concentrations
and its nitrogen nutrition is well maintained during the ripening
period. Therefore it appears that the main processes of its Calvincycle reactions are rapid, thus leading to a high photosynthesis
rate.

Leaf blade photosynthesis rate during the
mid-ripening period. (a) Rubisco content,(b) crop nitrogen absorption, and (c)distribution to leaf blades

When matching the CO2 concentrations (580 ppm) in smallchambers, the photosynthetic rates of rice plants raised underhigh-CO2 (FACE) and elevated-temperature conditions were on
average 23% lower than those for plants raised under control(current real-world) CO2 and non-elevated temperature levels (a).
There is a connection between this and the decline of rubisco,
the most important enzyme for photosynthesis, in the FACE
elevated-temperature group during the mid-ripening period (b).
Elevated temperature increased nitrogen absorption until the
mid-ripening period (c), but in the FACE elevated-temperaturegroup the proportion of nitrogen distributed to leaf blades waslow (d), which we believe to have caused the decreases in leafblade nitrogen and rubisco. Values for all groups are two-year
averages. **, *, and † indicate significance at 1%, 5%, and 10%
levels.

11

Research Overview in FY2013
mainly by the differences among crop models with respect
to CO2-temperature interaction.
b. Development of a method for wide-area assessmentof food production activities under global
environmental change, and future outlook
Research background
Future climate change and concomitant extreme
weather and meteorological disasters (drought, floods, etc.)
are expected to destabilize food production and supply
on a global scale. Research on the relationship between
climate change and agricultural production has thus far
focused mainly on the response to changes averaged
across years. However, the meteorological environment
is subject to yearly fluctuations, and the possibility thatclimate change in particular will concomitantly increase
the scale of these fluctuations has been suggested. Any
consideration of the impacts of climate change on
agriculture needs to focus on yearly fluctuations as well
as sporadic changes. Furthermore, because Japan imports
much of its food requirements, everyday life in Japan isclosely tied through price fluctuations to trends in foodproduction for global markets, as shown by the impactsof Australian wheat crop failures. Because maize andsoybean cultivation is unevenly distributed, with China,
America, and Brazil accounting for over 80% of the
global production of both crops, the risk that a worldwide
destabilization of the food supply would occur were thesemajor production regions to suffer extreme weather at thesame time cannot be denied. In this research area, we aredeveloping methods for assessing vulnerability to climatechange and predicting changes in food production volume
for both Japan and for the world's major crop production
regions.
Key results
i. Assessment of food production change in Japan
We used a rice growth and yield forecasting model for
Japan to assess the impacts of 18 climate scenarios on theyield and quality of 15 major rice cultivars; we evaluatedthe quality declines caused by high temperatures, withtransplantation days shifted at seven-day intervals withina span of ±70 days from present dates as a mitigation
measure. The results show that it would not be possible
to completely avoid high-temperature risk by onlychanging the transplanting period; other measures such aschanging cultivars will be necessary. These results are to
be released at the same time as the IPCC Working GroupII Report; it is hoped that the results will be reflected in
the government’s overall adaptation plan. We also createda model and indicators for the impacts of insect pests andtyphoons on changes in Japan’s rice productivity.
The relationship of air temperature and precipitation
12

change to yield became known from past reproducibility
experiments in a barley and soybean productivity model
created in 2012. For barley, the timing of changes in
impacting factors with respect to each growth stage (thatis, the heading and maturation days) is important; thisshows the necessity of implementing a new model for
estimating developmental stages.
ii. Downscaling climate change scenarios
We examined the usefulness of climate models for
impact assessments in light of reproducibility of surface
meteorological elements and other elements for Japan andworldwide. For the Japan region six models were chosen:
Two Japanese models (MIROC-5 and MRI-CGCM3),
the American GFDL, the Australian CSIRO-Mk3, theNorwegian bcc-csm, and the British HadGEM; for theworld, four models were chosen: The two Japanesemodels, the American GFDL, and the French IPCL. Using
the selected climate models, the Japan region was covered
with a 10-km grid using the existing weather generator
method, and the world was overlaid with a 1.125-degree
grid using the cumulative frequency function method. We
performed downscaling and bias correction for both, andprepared input climate data for assessing food productionchanges in Japan and worldwide.
iii. Assessment of worldwide food production changeWith respect to cultivation history, we expanded
a global data set used in a global crop productivity
model. For northeast China, where water resources are
the chief constraint on crop productivity, we performed
a composite impact assessment, using climate scenarios
and irrigated surface area; the results indicate that if theirrigated surface area was approximately doubled, it might
be possible to increase production providing that water
demand is met. We also used a world productivity model
to show that increased air temperatures over the last 30
years have decreased corn and rice yields worldwide
except in the US Midwest and southern China.
For wheat and rice, we created a multiple regression
equation that can estimate the yield of a certain year incomparison with the previous year from the differencewith the previous year in terms of the observed weather
conditions (air temperature and soil moisture) in thethree months of the latter growth stage. This has madeit possible to estimate global crop yields based solely on
weather conditions; formerly, such estimates were done
only for limited regions such as Australia. We found that
it is possible to accurately estimate yields for 30% of theworld’s cultivated wheat area, and 33% for rice (Figure1-5). When we supplied latter-growth-stage temperatureand soil moisture data predicted for the three months
prior to harvest by the Japan Agency for Marine-Earth
Science and Technology (JAMSTEC) into this multiple

Research Overview in FY2013
mainly by the differences among crop models with respect
to CO2-temperature interaction.
b. Development of a method for wide-area assessmentof food production activities under global
environmental change, and future outlook
Research background
Future climate change and concomitant extreme
weather and meteorological disasters (drought, floods, etc.)
are expected to destabilize food production and supply
on a global scale. Research on the relationship between
climate change and agricultural production has thus far
focused mainly on the response to changes averaged
across years. However, the meteorological environment
is subject to yearly fluctuations, and the possibility thatclimate change in particular will concomitantly increase
the scale of these fluctuations has been suggested. Any
consideration of the impacts of climate change on
agriculture needs to focus on yearly fluctuations as well
as sporadic changes. Furthermore, because Japan imports
much of its food requirements, everyday life in Japan isclosely tied through price fluctuations to trends in foodproduction for global markets, as shown by the impactsof Australian wheat crop failures. Because maize andsoybean cultivation is unevenly distributed, with China,
America, and Brazil accounting for over 80% of the
global production of both crops, the risk that a worldwide
destabilization of the food supply would occur were thesemajor production regions to suffer extreme weather at thesame time cannot be denied. In this research area, we aredeveloping methods for assessing vulnerability to climatechange and predicting changes in food production volume
for both Japan and for the world's major crop production
regions.
Key results
i. Assessment of food production change in Japan
We used a rice growth and yield forecasting model for
Japan to assess the impacts of 18 climate scenarios on theyield and quality of 15 major rice cultivars; we evaluatedthe quality declines caused by high temperatures, withtransplantation days shifted at seven-day intervals withina span of ±70 days from present dates as a mitigation
measure. The results show that it would not be possible
to completely avoid high-temperature risk by onlychanging the transplanting period; other measures such aschanging cultivars will be necessary. These results are to
be released at the same time as the IPCC Working GroupII Report; it is hoped that the results will be reflected in
the government’s overall adaptation plan. We also createda model and indicators for the impacts of insect pests andtyphoons on changes in Japan’s rice productivity.
The relationship of air temperature and precipitation
12

change to yield became known from past reproducibility
experiments in a barley and soybean productivity model
created in 2012. For barley, the timing of changes in
impacting factors with respect to each growth stage (thatis, the heading and maturation days) is important; thisshows the necessity of implementing a new model for
estimating developmental stages.
ii. Downscaling climate change scenarios
We examined the usefulness of climate models for
impact assessments in light of reproducibility of surface
meteorological elements and other elements for Japan andworldwide. For the Japan region six models were chosen:
Two Japanese models (MIROC-5 and MRI-CGCM3),
the American GFDL, the Australian CSIRO-Mk3, theNorwegian bcc-csm, and the British HadGEM; for theworld, four models were chosen: The two Japanesemodels, the American GFDL, and the French IPCL. Using
the selected climate models, the Japan region was covered
with a 10-km grid using the existing weather generator
method, and the world was overlaid with a 1.125-degree
grid using the cumulative frequency function method. We
performed downscaling and bias correction for both, andprepared input climate data for assessing food productionchanges in Japan and worldwide.
iii. Assessment of worldwide food production changeWith respect to cultivation history, we expanded
a global data set used in a global crop productivity
model. For northeast China, where water resources are
the chief constraint on crop productivity, we performed
a composite impact assessment, using climate scenarios
and irrigated surface area; the results indicate that if theirrigated surface area was approximately doubled, it might
be possible to increase production providing that water
demand is met. We also used a world productivity model
to show that increased air temperatures over the last 30
years have decreased corn and rice yields worldwide
except in the US Midwest and southern China.
For wheat and rice, we created a multiple regression
equation that can estimate the yield of a certain year incomparison with the previous year from the differencewith the previous year in terms of the observed weather
conditions (air temperature and soil moisture) in thethree months of the latter growth stage. This has madeit possible to estimate global crop yields based solely on
weather conditions; formerly, such estimates were done
only for limited regions such as Australia. We found that
it is possible to accurately estimate yields for 30% of theworld’s cultivated wheat area, and 33% for rice (Figure1-5). When we supplied latter-growth-stage temperatureand soil moisture data predicted for the three months
prior to harvest by the Japan Agency for Marine-Earth
Science and Technology (JAMSTEC) into this multipleregression equation, we found that the yields (whether theyield will be 5% or more below that of the previous year)of currently growing wheat and rice can be predicted forabout 20% (18% of wheat, 19% of rice) of the world’s
currently cultivated area (Figure 1-6). This research was
published in the British science journal Nature Climate
Change, and was also selected as one of 10 major topics
in agriculture, forestry, and fisheries research during
2013.

2. Investigation of mechanisms of variation in andenvironmental function of agro-biodiversity
Medium-term targets
Contributing
toenvironmentally
sustainableagriculture and other strategies that pay consideration tobiodiversity requires scientific assessment of the impactsof agriculture on biodiversity in agro-ecosystems and thebuilding of agricultural production systems that balance
productivity with the conservation of biodiversity.

Figure 1-5 Regions where grain yields could be accurately estimated from observed weather conditions.
The pie charts indicate the total cultivated land area of rice or wheat. Areas where yield changes could be accurately estimatedfrom temperature and soil moisture observed in the three months up to harvest are orange, and those that could not be estimated arewhite. Light gray areas did not have cultivation history data, and dark gray areas had very little cultivated surface area within the grid;
therefore, they were excluded from the analysis.

Figure 1-6 Regions where yields could be forecast from predicted temperature and soil moisture.
The pie charts indicate the total cultivated surface area of rice or wheat. Temperature and soil moisture up to harvest as predicted
by JAMSTEC’s model for three months prior to harvest were plugged into the multiple regression equation we obtained. Areas whereobserved crop failures could be reproduced are orange, and those that could not be reproduced are white. Areas where crop failures
could be reproduced from climate forecast values for three months before harvest corresponded to 18% of worldwide cultivatedsurface area for wheat, and 19% for rice. In blue areas, crop failures could not be reproduced from predicted values, but they could be
accurately predicted from observed values. Light gray areas did not have cultivation history data or weather prediction data, and darkgray areas had very little cultivated surface area within the grid. Therefore they were excluded from the analysis.
Note: Definitions of colors differ between Figure 1-5 and Figure 1-6.

13

Research Overview in FY2013
To this end, we will elucidate the mechanisms
governing fluctuations in biodiversity in agro-ecosystems
and develop technologies for conserving biodiversitythat is useful to agriculture. At the same time, we will
elucidate the biological and ecological functions that canbe leveraged for low-impact, environmentally friendly,and sustainable agricultural technologies.
(1) Investigation of mechanisms of variation in agrobiodiversity and development of appropriate
management technologies
To contribute to the development of sustainableagriculture that balances productivity with biodiversity,
we aim to elucidate the mechanisms whereby changes
in agricultural activities impact ecosystem structures andinteractions between biological communities; develop
methods for assessing and managing biodiversity that isuseful to agriculture; and develop methods for assessing
and managing the impacts of genetically modified crops,
etc., on ecosystems.
(2) Investigation of environmental biofunctions forenvironmentally friendly and sustainable agriculture
To develop basic technologies for low-impact andsustainable agriculture, we will elucidate biological andecological functions in agro-ecosystems, including thefunctions of physiologically active plant substances that
influence the growth of other plants, of chemicals related
to insect pheromones, and soil microbial functions capableof degrading agricultural materials.
Medium Term Plan
(1) Investigation of mechanisms of variation in agrobiodiversity and development of appropriate
management technologies
To balance agricultural production with theconservation of biodiversity within agro-ecosystems, we
aim to determine the responses of ecosystem structuresand representative biological communities to changes
in agricultural activities, and to develop methods forpredicting changes in biodiversity.
This would involve elucidating the impacts on, forexample, the interrelationships between plants, insects,
and birds of changes in patterns of ecosystem disturbancesuch as the increasing acreage of abandoned farmlands.
We also aim to develop biodiversity indices for assessing
the efficacy of initiatives such as environment-friendly
agriculture on biodiversity, and to develop assessment/
management methods that employ those indices.
Additionally, we will develop other tools for wide-area
biodiversity assessment/prediction that use the above
biodiversity indices and the Rural Landscape Information
System (RuLIS) for biodiversity conservation.
We also aim to develop methods for assessing
14

the impacts on biodiversity of alien species and crops
genetically modified to tolerate adverse conditions, andto develop management methods for enabling geneticallymodified (GM) crops to be grown alongside non-GM
crops.
(2) Investigation of environmental biofunctions forenvironmentally friendly and sustainable agriculture
To contribute to the development of environmentallyfriendly and sustainable agricultural technologies, wewill develop basic technologies for leveraging the usefulfunctions of organisms inhabiting agro-ecosystems. Morespecifically, we will identify chemical compounds thatmight lead to the development of new agrochemicals
and other agricultural materials by elucidating the action
mechanisms and ecosystem functions of allelochemicals
produced by legumes and other plants that may be usefulin weed control and other applications.
We will also identify semiochemicals involved in
insect-insect, insect-plant, and insect-plant-natural enemy
interactions, and elucidate their ecosystem functions todevelop methods for utilizing them.
Furthermore, we will use metagenomic analysis toelucidate the metabolism of soil microbes involved inmaterial circulation, and develop techniques for assessing
soil microbial properties. We will also identify microbes
and elucidate the functions and expression mechanismsof enzymes and related genes involved in degrading
biodegradable plastics, and develop technologies forcontrolling the degradation of agricultural materials madefrom such plastics.
Research Overview(1) Investigation of mechanisms of variation in agrobiodiversity and development of appropriate
management technologies
a. Effects of changes in agricultural activities on
biodiversity: impact analysis and assessment
methodology
Research background
Agriculture is a human activity concerned with the
production of food and other useful materials throughleveraging material cycles (such as photosynthesis,
decomposition of organic matter, water resource
replenishment and supply) that are mediated byorganisms in the natural world. Agriculture is accordingly
directly dependent on biodiversity and benefits provided
by ecosystems (ecosystem services). Agriculture also
impacts biodiversity in various ways. In places where thesame farming is practiced every year, unique ecosystems
such as the shallow aquatic environments of paddy fields
become established and provide valuable habitats formany different wild species.
However, agriculture also has adverse impacts
on biodiversity through the inappropriate use ofagrochemicals and fertilizers, and the developmentof farmland, water channels, and other agricultural
infrastructure that places undue priority on economic
gain or efficiency at the expense of biodiversity. In otherwords, agriculture and biodiversity are closely related
to each other, and as such, it is of vital importance that
we practice sustainable agriculture and manage rural
environments in a way that does not harm biodiversity
or ecosystems. To balance agricultural production withthe conservation of biodiversity, in this research area
we are elucidating the responses of ecosystem structuresand representative biological communities to changes
in agricultural activities, and developing methods forpredicting changes in biodiversity.
Key results
i. Finding relationships between abandoned croplandvegetation and land use
To determine, on a landscape scale, the response
reaction of biological communities to abandoning
cropland, on the Yura Peninsula of Ehime Prefecture (amontane landscape) we studied abandoned terraced fields
and the forest vegetation that had established itself nearby.
A multivariate analysis of the relationship between
species composition and environmental factors indicatesthat pre-abandonment land use strongly influences postabandonment species composition. To find the relationshipbetween land use and the progression of transition in
conjunction with farming abandonment, we conducted an
on-site study of the area covered by Tone River watershed
RuLIS monitoring in 2012, prepared a 2012 land use mapthat could be compared to a land use map corresponding
to past monitoring data; we then analyzed the relationshipbetween the surface-area proportion of each community
type and land use, according to agro-ecosystem landscape
type. In parts of the Tone River watershed (rice paddy
landscape) where conversion of higher ground toresidential land has progressed, and time has passed sincecropland abandonment, there was much characteristic
vegetation. As the relationship between land use and theprogression of transition in conjunction with farming
abandonment has become clear, it is expected that thiswork will serve as a basis for assessment and forecastingstudies.
ii. Effects of conservation agriculture and landscapestructure
To develop a new conservation agriculture assessment
method that uses birds as representative species, we
explored methods of studying birds and their preyspecies: insects, and plants. Using a provisional method,

we investigated fields under conservation agriculture
and conventional agriculture in the Kanto region; wewere able to discern the biodiversity conservation effectof conservation agriculture in a number of taxonomic
groups from birds to arthropods and plants. To determineon the landscape scale the effects of farming methods
on indicator species groups, we conducted a study ofindicator species groups (spiders, frogs, and dragonflies)that show the effects of conservation agriculture in two
groups of 10 rice paddies each cultivated with special
and conventional methods, located in zones with different
landscape structures ranging from low-lying valleys
to level land in Tochigi Prefecture’s Shioya Town. We
used model selection in a generalized linear model toanalyze the influence of farming method and landscapestructure on the number of individuals in each indicatorspecies group, and found that the number of individuals
was influenced by farming method and landscape, andthat the influencing factors differed for species groups(Figure 2-1). We also used the data from last year’s
spider study in a path analysis to reanalyze the influenceof landscape structure; we discovered that for Tetragnatha
genus spiders, surrounding forests indirectly have apositive influence on the number of spider individuals by
increasing spider prey resources.
Using the knowledge that the traditional tea-grass
integrated system contributes to maintaining biodiversity,
which became known in 2009, this system in Shizuoka
was certified as a Globally Important Agricultural
Heritage System in May 2013. Additionally, the Council
to Promote Shizuoka’s Traditional Tea-Grass Integrated
System, which was established through the cooperationof five local municipalities, has created a “Certification
Program for Tea-Grass Integrated System Practitioners,”
which it uses to fortify its marketing strength.
iii. Assessment of habitat environments using the Rural
Landscape Information System
As a wide-area assessment using the Rural Landscape
Information System (RuLIS), and in order to assesschanges in suitability as habitat induced by croplandpreparation, we used RuLIS monitoring data for theTone River watershed, as well as GIS data for croplandpreparation status, which is available for all of Japan,
to assess habitat environments for native plants. Whencrop preparation data indicated that a plot was irregularly
shaped, or that it was under 0.2 ha in size, it was assumed
to be an “unimproved paddy,” and all other paddies
were considered to be “improved paddies.” An analysis
of 2007 data indicates that the number of native plant
species in idled paddies (wetland plant communities)
was significantly lower in improved paddies than in
unimproved paddies, which means that the suitabilityof idled paddies as habitat for native plants changes
15Research Overview in FY2013
depending on whether they have been improved. On theother hand, there were no significant differences among
currently used paddies (Spirodela polyrhiza–Monochoria
vaginalis communities), dry abandoned paddies (Solidago
canadensis communities), or wet abandoned paddies(Phragmites australis–Typha latifolia communities).
Idled paddies not only have high species diversity,
but are also known for the appearance of rare wetland
plants. This research shows that whether a paddy has been
improved could possibly be a habitat indicator showing
the suitability as plant habitat of rice paddy ecosystems.
b. Development of methods to assess the impacts ofgenetically modified (GM) crops and alien species
on biodiversity, and to manage the cross pollinationand mixing between GM and non-GM crops
Research background
The Japanese government drew up the Act on theConservation and Sustainable Use of Biological Diversity
through Regulations on the Use of Living Modified
Organisms (Cartagena Law) to guard against adverse
effects of the use of genetically modified (GM) organisms

殺虫剤不使用

殺虫剤不使用Figure 2-1

on biodiversity. With GM crops now being grownworldwide, Japan needs to develop a body of scientificknowledge in preparation for commercial cultivation even
if GM crops are not currently being grown in the country.
Furthermore, alien species entering Japan have increased
rapidly as a result of international trade and exchanges,
and there is concern that the spread of these species will
disturb ecosystems and adversely affect the agriculture,
forestry, and fishery industries in Japan. Countermeasures
have been formulated under the Invasive Alien Species
Act, but ensuring that they are effectively implemented
requires relevant scientific knowledge. As such, in thisresearch area, we are developing methods for assessing
how biodiversity is affected by crops genetically modified
to tolerate adverse conditions or by alien species, anddeveloping management methods for enabling GM crops
to be grown alongside non-GM crops.
Key results
i. Development of a method to assess the impacts on
biodiversity of genetically modified crops and alienplantsWe assembled informational materials on the

殺虫剤不使用

殺虫剤不使用

殺虫剤不使用

殺虫剤不使用Influence of farming method and landscape structure on the number of individuals in indicator species
groups (spiders, frogs, and dragonflies).

Positive (+) explanatory variables indicate positive influence on numbers of individuals, and negative (−) explanatory variables indicate
negative influence. Gray-shaded factors are those that were not selected as explanatory variables.
Influencing factors and the mode of influence (whether positive or negative) differed depending on indicator species groups andindividual species.

16

ecological characteristics (such as growing environments,
dormancy, and germination temperature) of Brassica
juncea, Brassica rapa L. var. nippo-oleifera, Glycine soja,
and other species that are closely related to geneticallymodified crops, and that grow wild in Japan. We also
investigated the insect fauna that feed on Glycine soja,
and identified, among others, six Coleoptera species; twoHemiptera species; Lepidoptera insects including noctuid
moths, Tischerioidea moths, Tortricidae moths, Pyralidae
moths, and Geometridae moths; of Diptera, Agromyzidae
flies; and of Orthoptera, Atractomorpha grasshoppers.
We further used National-Land Numerical Informationand other data to assess the habitat of Glycine soja;
among other things, we found that i) the plant appears
often in 1 km grid squares, in which dominant vegetation
includes marsh herb communities and rice paddy weed
communities, and in 1 km grid squares in which muchland is used by rice paddies (about 40%) and forest (about25%); and ii) the plant hardly grows at all in Hokkaido
and alpine regions of central Honshu, and also that it does
not grow in areas with much land transformation. Thesefindings are necessary when assessing the impacts of GM
crops on biodiversity.
In a study of alien plants, which pose a great risk ofrunning rampant, for each species we analyzed the soil
environments where they grow and the plant nutrition
characteristics. Results suggest that differences innutritional requirements for phosphates are reflected in
the differences in soil environments where alien species
with a high risk of spreading grow, such as Solidago
canadensis and Festuca arundinacea, and where thenative plant Potentilla freyniana grows.
ii. Development of a method to determine the extent
to which alien species have invaded and establishedthemselves, and to assess and forecast increases in
distribution
We monitored the golden mussel (Limnoperna
fortunei) in the water supply facility network thatwithdraws water from Lake Kasumigaura in Ibaraki
Prefecture and serves an area as far as the Naka Riversystem, and determined the extent of the organism’s
habitation. To build a model that predicts suitable goldenmussel habitat in the water supply facility network, we
performed model selection using a generalized linear
mixed model; the model selected parameters includingpH, electrical conductivity, distance from supply site, andtrap siting. Additionally, golden mussel habitation surveys
conducted in 2006 and 2012 along the entire shore of Lake
Kasumigaura found that during six years the organism
had expanded its distribution in the lake to a point about
10 km (Figure 2-2). Calculations based on this expansion
distance indicate a probability of at least 99% that in 2018the organism will have newly established itself in theplaces found free of it in the 2012 survey (Figure 2-3).
We issued a press release about these results, and it wascovered by many media.
For invasive insect pests for which information about
their biological characteristics and distributions havebeen collected, we developed a method to determine
the characteristics of insects emerging as agricultural
pests and to predict their future enlarged distributions.
To do this, we merged the Asia-Pacific Alien Species
Database (APASD) into a database on the world’s major
agricultural pests (CPCJ), which has little Asia-related
information, to create the Assessment and Distribution
Prediction Database on Insect Pests Not Yet Found inJapan (NAPASD).
iii. Development of a method to control hybridization
and adulteration by genetically modified crops
To obtain parameters for use in a model to assess andpredict hybridization by flowering overlap of rice plants
as a technique for the proper control of GM crops, wetransplanted and cultivated combinations of two cultivars
each of early- and late-maturing varieties; during thecultivation period, we conducted a study including
weather conditions, number of flowering panicles, amountof pollen released over time, and the hybridization rate,
and then calculated the degree of flowering overlap.
Additionally, we used the hybridization rate as estimatedfrom the pollen dispersal amount and DNA analysis toassess the relationship between the degree of flowering
overlap and the hybridization rate. Results confirmed
that, except for a few outliers, there is a weak positive
relationship between the degree of flowering overlap andthe hybridization rate.
(2) Investigation of environmental biofunctions forenvironmentally friendly and sustainable agriculture
Research background
Many organisms in the natural world use chemical
substances as signals to communicate with other membersof their own species or with other species. The chemical
substances released by organisms serve many different
purposes, including finding mates, eliminating competitorsand searching for food. Substances that perform thesefunctions are known as semiochemicals. Identifying
these semiochemicals and elucidating their functions
is important for the appropriate management of agroecosystems and development of sustainable production
technologies that make use of ecosystem functions. To
contribute to the development of environmentally friendly
and sustainable agricultural technologies in this researcharea, we are developing basic technologies for leveraging
useful functions of semiochemicals used by organisms
inhabiting agro-ecosystems.
17

Research Overview in FY2013

99%以上

Figure 2-2

Golden mussel distribution
along the Lake Kasumigaura
shore.

Sizes of red circles indicate the number ofindividuals one survey worker collected in 10
minutes. Surveys found the mussel living along
45.6% of the shore in 2006, and 83.2% in2012.

Figure 2-3

The prediction figure for 2018 shows locations with an estimated establishment
probability of at least 99% as “habitat.” It was predicted that in 2018, themussel will be established along the entire lakeshore. Percentages shown in the
figure are the percentages of the shoreline inhabited by the golden mussel.

Key results
i. Use of allelochemicals as herbicides
A constituent isolated as a plant growth inhibition
substance from fallen Himalayan cedar leaves was
identified as abscisic acid. An assessment of abscisic
acid’s activity in the presence of three soil types (volcanic
ash soil, calcareous soil, and alluvial soil) found that,
unlike the allelochemicals that have been measured thus
far (such as L-DOPA), abscisic acid’s activity does notdecline even in the presence of soil, making it a promising
candidate as an herbicide.
ii. Use of semiochemicals to control insect behavior
We worked out the complex composition of thearomatic constituents of komatsuna (Brassica rapa var.
perviridis) flowers and determined the release dynamics
of the main constituents. In laboratory behavior tests wedemonstrated that the fragrance constituents, which arereleased in greater amounts during the day, independently
attract a hungry parasitic wasps, Cotesia vestalis, which
prey on Plutella xylostella larvae. We applied for a patenton these constituents. This accomplishment will be a new
basic technique of insect pest control that controls the
behavior of natural enemies.
18

Changes in golden mussel distribution along Lake
Kasumigaura shore (left: 2006 and 2012) and predicted
future expanded distribution (right: 2018).

iii. Elucidation of soil microbial functions and assessmentof soil material circulation functions
It was previously believed that in agro-environments
the important process of nitrification, a part of thenitrogen cycle that is involved in greenhouse gas
emissions and groundwater pollution, was performed byammonia-oxidizing bacteria (AOB); however, researchin recent years suggests the possibility that ammoniaoxidizing archaea (AOA) are involved. We therefore
applied an archaea community analysis method, whichuses environmental DNA, to the soil in test agriculturalplots, which differed in soil types and fertilizer types.
We then tracked the changes in soil nitrification activity(nitrification activity potential) and the density of theammonia-oxidizing archaea AOA amoA, which have thegene (amoA) that oxidizes ammonia, the initial reactionof nitrification. We found that as nitrification activity
increases after fertilizer application, there was indeed an
attendant increase in the density of ammonia-oxidizing
bacteria (AOB) amoA, which were the only bacteriapreviously thought to carry out ammonia oxidation;
however, there was also a similar increase in AOA amoA
density. The density of AOA amoA was higher than thatof AOB. There was a positive correlation with nitrification

activity especially in light-colored andosols and graylowland soil, suggesting a contribution of a certain degree
to nitrification in soil. This suggested that in order toassess the nitrogen cycle in cropland soil, especially thenitrification process, it is necessary to include archaeagroups among the soil microorganisms analyzed.
iv. Development of technologies for controlling thedegradation of agricultural materials made frombiodegradable plastics.
When there was a small amount of oil in a liquid
culture medium containing the yeast Pseudozyma
antarctica, it produced the biodegradable plastic
decomposition enzyme PaE; in the latter stage of cellproliferation, the yeast secreted a mannosyl erythritol lipid(MEL) that inhibits the activity of PaE. Based on theseresults we continuously added a basic culture medium
containing sugars to a jar fermenter, and intermittently
added oil, thereby creating a new culturing method thatstably produces PaE in large quantities. At the sametime, we applied for an international patent on a method
for even more efficiently producing PaE using genetic
recombination technology.
To perform a real-time analysis of how the enzyme
is adsorbed onto the surface of biodegradable plastic(solid) and decomposes it, we came up with the idea ofusing a surface plasmon resonance device, and obtained
results for the characteristics of PaE and mold enzymes.

Figure 2-4

In an effort toward practical application, we determined
the relationship between the compositions of 21 kindsof commercially sold biodegradable plastic mulch anddecomposition with enzymes. Further, on multiple
occasions at private sector factories, we obtained basic
jar culturing data for the manufacture of biodegradable
plastic decomposition enzymes.
We found that a cutinase-like biodegradable plastic
degrading enzyme produced by a kind of mold (filamentous
fungus) obtained from the surface of barley leaves candecompose many kinds of biodegradable plastic (Figure2-4). This enzymatic decomposition activity on a wide
variety of biodegradable plastics is a useful characteristic
for developing decomposition-facilitating technologies touse on biodegradable plastic materials.
3. Dynamics of agrochemicals and methods of
reducing their risks in agro-environments
Medium-term targets
Technologies to reduce cadmium (Cd) content inpaddy field soil and other measures to improve the safetyof agricultural produce have been developed, but problems
still exist in the risk management of heavy metals otherthan Cd in paddy fields, heavy metals in dry fields, andpersistent organic pollutants (POPs). Stable, sustainable,
and low-impact agricultural production also requires
an understanding of material cycle functions within

Decomposition activity of the biodegradable plastic decomposition enzyme from the B47-9 strain on
various kinds of biodegradable plastic film.

This enzyme was tested on several kinds of biodegradable plastic films, and exhibited degradation activity on PBS, PBSA, PBAT, PCL,and PDLLA. The biodegradable plastics decomposed by the enzyme are representative types that are blended into commercially soldbiodegradable plastic mulch and other products.
Note: PBS is polybutylene succinate, PBSA is polybutylene succinate adipate, PBAT is polybutylene adipate terephthalate, PCL ispolycaprolactone, PLLA is poly-L-lactic acid, PDLLA is poly-DL-lactic acid, and PHB is polyhydroxybutyrate.

19

Research Overview in FY2013
agro-ecosystems and of the impacts on ecosystems offertilizers, agrochemicals and other chemical substances
derived from farming activities.
We will accordingly seek to improve technologies for
reducing the risk of contaminating agricultural producewith hazardous chemicals, and to develop methods forpredicting the dynamics of chemicals derived fromfarming activities in agro-environments and assessing
their impacts.
(1) Development of technologies for reducing the risk ofcontaminating agricultural produce with hazardous
chemicals
To reduce the risk of contaminating agricultural
produce with hazardous chemicals such as Cd, arsenic(As) and POPs in agro-environments, we will seek to
elucidate the dynamics of these chemicals in soil-crop
systems, and to improve risk reduction techniques basedon contamination risk prediction techniques and on
methods that use plants and physical or chemical means.
(2) Methods of predicting the environmental dynamics ofagro-chemicals and evaluating their impacts on agroecosystems
We aim to use numerical models of the dynamics
of nitrate nitrogen, phosphorus and other nutrients,
and pesticides and other organic agrochemicals inagro-environments to develop methods for predicting
their environmental loads and assessing the impacts
on ecosystems of chemicals derived from agricultural
production.
Medium Term Plan
(1) Improvement of technologies for reducing the risk ofcontaminating agricultural produce with hazardous
chemicals
To reduce the risk of contaminating agricultural
produce with hazardous chemicals such as Cd, As, andPOPs in agro-environments, we will seek to elucidate thedynamics of these chemicals and the mechanisms of theirabsorption by plants in soil-crop systems, and to improverisk reduction techniques based on contamination risk
prediction techniques and on methods that use plants andphysical, chemical and other means.
In other words, we aim to develop techniques forforecasting the contamination risk to crops based on theextent of soil contamination, for POPs in the case ofvegetables, and Cd in the case of major dry field crops.
To decrease the concentrations of Cd in dry field
crops, arsenic in wet rice, and POPs in vegetables, we also
aim to leverage plant functions and physical and chemical
methods to develop soil remediation technologies andcultivation techniques that curb absorption.

20(2) Methods of predicting the environmental dynamics ofagro-chemicals and evaluating their impacts on agroecosystems
We aim to use numerical models of the dynamics
of pesticides and other organic agrochemicals, as wellas nitrate nitrogen, phosphorus, and other nutrients inagro-environments, to develop methods for predicting
their environmental loads and assessing their impacts onorganisms.
More specifically, we will develop numericalmodels that comprehensively and quantitatively simulate
the dynamics of agrochemicals and nutrients throughwatersheds that incorporate paddy fields, and methods
for assessing the environmental load of nonpoint
source pollution and remediation technologies. We
will also develop methods for assessing the impacts ofagrochemicals on biotic communities of aquatic animals
and plants, and probabilistic methods for assessing theimpacts of agrochemicals on ecosystems.
Research Overview(1) Improvement of technologies for reducing the risk ofcontaminating agricultural produce with hazardous
chemicals
Research background
Farmland soil can become contaminated withhazardous chemical substances in various ways, including
seepage from river systems of calcium and arsenic
originating in mines and smelters, presence of POPs inagricultural materials, and presence of contaminants in
atmospheric precipitation. As a result of absorption ofsuch soil contaminants by crops, the concentration of
hazardous chemical substances in agricultural produce
and sometimes exceed food safety standards. In thisresearch area, we are seeking to ensure food safety withrespect to hazardous chemical substances by studying
risk assessment methods for predicting the degree ofabsorption of such substances by crops and risk reduction
methods for minimizing such absorption.
Key results
i. Development of crop contamination risk forecasting
techniques
For the purpose of developing a method to predictthe risk of residual pesticides for succeeding crops, weanalyzed the influence of pesticide and soil physical andchemical properties on the soil adsorption of various
pesticides. We found that with pesticides that havearomatic rings and flat structures, the soil adsorption
equilibrium coefficient (Koc) is specifically high, and thatsoil aromatic carbon affects pesticide adsorption. We usedvarious kinds of paddy soil with different characteristics
in an analysis of the major factors influencing arsenic

absorption by rice plants, then used multivariate analyses
and other means to create a prototype formula to predictbrown rice arsenic absorption, which incorporates
parameters including soil arsenic content. These research
results will help administrative authorities devise remedial
measures.
International agencies are now discussing standards forarsenic concentration in rice, making increased analysis
demand likely in the future. For arsenic acid, arsenousacid and organic arsenic we found liquid chromatography
separation conditions for arsenic compounds underwhich the analysis time per analyte is short, no burden
is imposed on analysis equipment even if used for many
hours each day, and the analysis uses only a simple andvolatile mobile phase. This was developed into a stable
analytical method. Using this separation method reduces
the frequency of instrument maintenance and makes it
possible to accommodate increasing analysis demand.
(Figure 3-1, Figure 3-2)
ii. Development of contaminated soil remediation
technologies
To produce phytoremediation rice plants for
cadmium, we plan to proceed with yield trials of high-Cdaccumulating rice plants endowed with shatter resistance,
narrow them down to a final strain, and apply forcultivar registration within the fiscal year. We developed
DNA markers for highly functional phytoremediation
rice plants, and selected a total of 11 strains in two
groups having characteristics such as high yield, highsoil cadmium uptake, colored rice, and high lodging

Figure 3-1

Liquid chromatographyarsenic compounds.

separationofArsenic acid, arsenous acid, monomethylarsonic acid, anddimethylarsinic acid can be separated within 4 min. It is also
possible to separate arsenobetaine, trimethylarsine oxide, andother arsenic compounds that are found in fish and shellfish; themethod holds promise for application to foods other than rice.

resistance. These chosen strains are especially superior
with regard to lodging and plant form, and hold promise
as new highly functional rice plant strains that have highlodging resistance and high biomass.
In soil that had been contaminated with melamine
due to the application of lime nitrogen, we conducteda decomposition test using charcoal impregnated withmelamine-decomposing bacteria; we confirmed its
decomposition effectiveness in melamine-contaminatedsoil. This opens the way to the quick decomposition ofresidual melamine in soil.
iii. Development of cultivation techniques that suppress
Cd absorption
We applied for registration of a low-cadmium
rice cultivar (named “Koshihikari Kan No. 1” inthe application) and issued a press release about it.
Additionally, we improved a DNA marker that is usefulin making various low-cadmium cultivars. We are also
conducting joint study with six prefectures for developing
recommended varieties. We found that absorbed arsenic
in brown rice can be substantially reduced by switchingwater management from flooding paddies, which is used
to mitigate cadmium absorption, to intermittent irrigation,and further to water conservation management. By
using low-cadmium rice plants, the amount of cadmium
absorbed by brown rice — which in terms of water
management has a tradeoff relationship with arsenic — isvirtually below the detection limit, and therefore there are
expectations that arsenic absorption by brown rice can be
reduced by using water management.

Figure 3-2 Chromatogram of a rice fluid sample.
In fluid samples for rice as well, the peaks for arsenic
compounds were completely separated and quantified with noproblem (Japanese rice contains hardly any monomethylarsonicacid).

21

Research Overview in FY2013
Several kinds of iron materials checked for theireffectiveness at limiting arsenic leaching were provided
for use in paddy testing (always flooded); we judged theireffectiveness at limiting arsenic absorption by rice plants.
We found that, in comparison with the paddy given noiron, the materials were effective in limiting arsenic inbrown rice grown in constantly flooded paddies, witheffectiveness increasing in the following order: ordinaryiron material ≤ iron oxide < zerovalent iron. Effectivenessin lessening arsenic in brown rice was demonstrated inrice paddies. We also developed a solubility assessment
method for iron materials by using a stable iron isotope
as a tracer.
iv. Development of risk-reduction techniques for paddies
contaminated with radioactive cesium
We continued developing a practical remediation
technique for paddies whose soil has coarse particles.
The technique involves adding water and dispersant(sodium hydroxide) to the paddies, dispersing fine soil
particles with radioactive Cs in high concentrations, anddraining radioactive Cs from the paddies along with thesoil particles. The concentration of soil 137Cs declined to
50% of the pre-decontamination level, and 137Cs in brownrice declined to 49% that of the control paddy. We also
confirmed the sustained remediation effectiveness inrice paddies that were remediated last year. Fukushima
City is scheduled to begin a verification program for this
remediation method.
Three rice strains (C-8-6-22, C-8-7-4, and A5-4-17)
preliminarily chosen from mutant Koshihikari plants
produced by bombardment with a heavy ion beam were
cultivated in NIAES paddies and Fukushima paddies.
We measured the 133Cs (NIAES) or 137Cs (Fukushima)in brown rice and found a decreased concentration inbrown rice Cs for all three strains. Notably in A5-4-17,
the decrease was at least 50%. Because we obtained
promising strains, next we intend to work on verifying
their local adaptability.
(2) Methods of predicting the environmental dynamics ofagrochemicals and evaluating their impacts on agroecosystems
Research background
Many different kinds of chemical substances, including
pesticides and fertilizers, are used in agriculture. These
substances are essential to maintaining high levels of crop
production. However, some of these chemicals flow out of
the farmlands on which they are used, affecting the qualityof groundwater or surface water and adversely impacting
riverine ecosystems. Efforts are being made to reduce
the quantities of fertilizer and agrochemicals used on
farmlands, but there are still many unanswered questions
22

regarding how to practice more eco-friendly agriculture
while maintaining current levels of crop production,
how to use chemical fertilizers or compost in ways that
help improve watershed groundwater and surface water
quality, and how, when faced with multiple agrochemicals
that have much the same effects, to choose the productsthat will least impact riverine ecosystems. Finding
answers to such questions based on scientific methods
requires the development of methods for quantitatively
assessing the impacts of agrochemicals on water quality
and ecosystems outside the farmlands on which they areused. In this research area, we are developing methods
for quantifying the impacts of agrochemicals (pesticides
and nutrient salts originating from agricultural activity)
on water quality and ecosystems outside the farmlands onwhich they are used, and for assessing technologies for
reducing the area source load of nutrients.
Key results
i. Methods of predicting the environmental dynamics ofagrochemicals and evaluating their impacts on agroecosystems
We used the pesticide environmental dynamics
prediction model GIS-combined PADDY-Large by
dividing a river into 250-m segments and calculated
herbicide concentrations in river water; we then prepared
curves showing the probability of excess concentrations
for the maximum concentration in each segment.
By overlaying these curves onto species sensitivity
distributions, it was possible to quantitatively assess theecological risk of pesticides.
We devised test conditions for a fluorescent
microplate assay method to conduct simultaneous toxicity
testing on five species of attached algae (one green alga,
one blue-green alga, and three diatoms) that can represent
Japan’s river ecosystems (Figure 3-3), described the test
method in detail in a manual (Figure 3-4), and released
the toxicity text method. Additionally, we applied thistoxicity test method to 15 herbicides, and found that thesensitivity of attached algae is lower than that of standard
green algae. Further, we conducted a compound toxicity
test using a mixture of five herbicides: the results showthat if mechanism differences are considered, it is possible
to predict test results by selecting an existing model. This
test method will make it possible to efficiently build astore of toxicity data on primary producers in Japan’srivers, and make a major contribution to the ecologicalrisk assessment of pesticides.
ii. Methods of predicting the environmental dynamics
of nutrient salts and assessing technologies forminimizing their environmental load
We applied LEACHM, a model that predicts the
dynamics of water, carbon, and nitrogen in cropland,Figure 3-3 Test method using Erlenmeyer flasks changed to a test method using microplates.
Because algae are attached to flask walls, the flask method is difficult to apply to attached algae, but the new test method measuresbiomass with algae attached to the microplate bottoms.

to different types of cropland soil. Additionally, we
cataloged the prediction accuracy (IA values good in
the 0.5–1.0 range) of LEACHM for water movement,
nitrogen leaching, and other phenomena in a total of
12 cropland plots with different soil and fertilization
management conditions. We found that IA>0.5 forvirtually all items and plots, and that the model has
sufficient prediction accuracy for use in wide-area
assessments. We also applied SWAT, a watershed-level
model for water and substance dynamics that is being
improved for use in watersheds with many rice paddies,and the conventional SWAT model, to paddy and nonpaddy watersheds, respectively, compared the measured
and predicted values for river flow rate, concentrations ofsuspended substances, and other attributes, and confirmed
their sound prediction accuracy.
We also investigated two versions of SWAT, awatershed-level model for water and substance dynamics.
The conventional version and the improved version forwatersheds with many rice paddies were applied to paddy
and non-paddy watersheds, respectively.
iii. Development of a method to predict radioactive
cesium dynamics
In various croplands and watersheds in Fukushima
Prefecture, we measured the dissolved and suspended
radioactive Cs concentrations (collected on a filter with a
0.025 µm pore size) of atmospheric fallout, irrigation anddrainage water, river water, and others at times of paddy
puddling events and every month when river levels werenormal. With these partition coefficient (Kd) results, wefound that, among other things, Kd fluctuates broadly inthe range 103–106 L/kg, the Kd of many water samples
declined in tandem with electrical conductivity, and the
Kd of atmospheric fallout declined in tandem with theconcentration of dissolved organic carbon.

Figure 3-4 Manual cover.
A PDF file of the manual can be downloaded from the NIAES
website.

4. Advancing agro-environment inventory
Medium-term targets
We will seek to advance our agro-environment
inventory (mechanisms for the systematic storage,
utilization, and provision of agro-environment data,
research findings, and other information or samples) withthe aim of strengthening the foundations for research on
agro-environments from the perspectives of addressing
agricultural aspects of global warming, conserving
23

Research Overview in FY2013
biodiversity, and promoting research for ensuring thesafety of agricultural produce.
To this end, we will build advanced agroenvironment monitoring systems, develop new remotesensing technologies, and collate and expand our
agro-environmental information resources. We will
also build an integrated database for the centralized
provision of desired information. Additionally, we willdevelop methods for the comprehensive assessment ofenvironmental impacts that consider key aspects of both
environmental conservation and agricultural productivity.
Medium Term Plan
(1) Monitoring and predicting agro-environmental
dynamics
usinggeoinformationandflux
measurement
To aid the computerization and wide-area assessmentof agro-environmental resources, we aim to develop
technologies to analyze remote sensing data by using
hyperspectral imaging and heretofore unused wavelength
bands, and to develop highly accurate, wide-area
assessment methods for ecosystem dynamics including
crop productivity, land use, vegetation coverage, and soil
properties.
We aim to combine these methods with findings
from terrestrial observations of temporal fluctuations in
gas flux, plant-soil gas exchange dynamics to develop
a system for the wide-area monitoring and prediction of
GHG flux, water and carbon dynamics, crop productivity,and other aspects of biophysical ecosystem dynamics.
(2) Collation of agro-environmental information anddevelopment of an integrated database
To facilitate the use of agro-environmental resources
and information on them, we will build and expand
individual databases for soil, insects, weather, and otheraspects, and develop data utilization methods. In addition,
we will monitor levels of radioactive substances in theagro-environment over time.
We also aim to build an integrated database for thecentralized provision of nationwide agro-environmental
information including data on soil, weather, organisms,
land use, satellite images, and agricultural statistics.
Furthermore, to assist the creation of agro-ecosystemmanagement scenarios aimed at balancing high agricultural
productivity with environmental conservation, we aim todevelop an integrated environmental impact assessment(ecobalance assessment) method that makes use of diverse
spatial information, models, LCA methods, statisticalmethods, and more, and takes into consideration factors
such as GHG emissions, soil carbon storage, biodiversity,
leaching of nitrate nitrogen into groundwater, wide-area
nitrogen flow, and productivity.

24

Research Overview(1) Monitoring and predicting agro-environmental
dynamics
usinggeoinformationandflux
measurement
Research background
Concern has grown in recent years regarding theimpacts of climate change on food production, and ofagro-ecosystems or agricultural production activities onwater and air quality. As such, accurately monitoring andrecording changes in land use, crop growth, water runoff
and CO2 emissions from agro-ecosystems, and otherparameters has become increasingly important. In thisresearch area, we are seeking to accurately monitor suchchanges in agriculture and the environment over wide
areas in real time by using earth observation satellites
and other tools to carry out remote-sensing. We arealso developing advanced methods and monitoring andprediction systems for observing, analyzing, and recording
the flux of trace gases such as CO2 at the ecosystem levelby using flux observation networks that continuously
quantify such measures.
Key results
i. Development of a method that uses remote sensing toassess information on crops, agricultural management,
and land use
For hyperspectral measurement methods with
community chlorophyll amount being the main targetchange, we used a diverse data set (four countries, sixvegetation types) to conduct cross validations withmethods including indexing methods using reflection
ratio, derivatives, and other values; multivariate analysis
methods such as PLS identified the advantages andlimitations of each method. Additionally, we developed
a new assessment model (CCCsp) that has high accuracy
and versatility. There are expectations that this prediction
model will find broad application in predicting crop
productivity and in making wide-area determinations of
natural vegetation degradation.
In work on a wide-area crop determination methodthat uses time-series optical satellite data, we verified theeffectiveness of a new algorithm and correction method
for corn in the US corn belt; also, we verified that it
can detect the regional variability of drought impacts
as distribution information. As a method for the early
prediction of yield per unit area, we confirmed that it
can be used on the practical level for estimating the crop
situation in advance (Figures 4-1 and 4-2).
We worked on ways to use a new synthetic apertureradar (SAR) satellite sensor to effectively use signals(backscattering coefficient σ0) observed by X-band andC-band satellite SAR sensors for the wide-area and timely
measurement of crop and cropland information; weexplored basic relationships including observed signals
and crop traits, as well as methods of assessing them,and developed an effective new method of assessing rice
plant growth and yield traits (Figure 4-3). We also usedhigh-resolution satellite SAR sensors to determine thesignal characteristics for the wide-area measurement, on
the scale of individual fields, for transplanting time andother primary management information. The findings andmethod obtained in this research will play an importantrole in applying diverse satellite SAR, for which there
are many launch plans, in precision agriculture and yield
forecasting, and for collecting statistical information.
ii. Upgrading systematic observation and quantitative
assessment methods for gas flux dynamics
We continued our continuous gas flux observations atsites in Japan and abroad, chiefly at Mase in Tsukuba City,
Ibaraki Prefecture. We used a different measuring method,the eddy correlation method, to simultaneously measure
rice paddy methane emissions, and found a systematic
correction method to assure the interchangeability andconsistency of observation data. We also networked theflux observations and accumulated data including thosefor indicator ecosystems.
To elucidate and model the basic processes of
ecosystem gas exchange, we developed a new continuous
measuring method with high time resolution; the method
includes a high-speed, multi-channel, continuousmeasurement system for plant leaf CO2 diffusion resistancethat joined multiple chambers and a photosynthesis andevaporation measuring system connected to a CO2 isotope
measuring device. This system enabled analyses suchas those for environmental response and inter-cultivar
differences in CO2 diffusion resistance in relation tophotosynthesis.
iii. Wide-area assessment of ecosystem dynamics bybuilding the Satellite–Ground Ecosystem Monitoring
SystemLast fiscal year we finished developing a systemthat automatically collects data in semi-realtime fromecosystem observations and builds a database (SGEMSD); this system was used as the core element in building
the prototype of the “Satellite-Ground Ecosystem
Monitoring System SGEMS,” whose purpose is to
manage and provide a calculation system plus the productand data in an integrated manner. We started operating thesystem and proceeded with tasks including expanding its
observation sites and observed items, and preparing ultraprecise maps of land use and land cover information.
To integrate point measurement data on flux andother phenomena with satellite data and perform widearea assessments, we used high precision data fromhigh-resolution satellites to analyze the characteristicsof MODIS images (low-resolution, high-frequency
observation data), and devised a systematic scaleaugmentation method that uses flux, satellite, andother data of different types in an integrated manner
to perform wide-area gross primary production (GPP)
assessments. We also completed GAEN-View, a web-

かんがい圃場天水圃場

2010 年収穫直前に起きた雹嵐被害トウモロコシ単位収量(t/ha)

トウモロコシ単位収量(t/ha)

雹嵐被害

Relationship between the MODIS wide
dynamic range vegetation index (WDRVI)
10 days before silking stage and corn yield
per unit area.

These results indicate that it is possible to predict the final
corn yield per unit area from the growth of assimilatory organs(leaves) up to the final stage of vegetative growth observed by
MODIS.

統計データ

年

植生指数(WDRVI)
Figure 4-1

MODIS 推定値

Figure 4-2

Yearly comparison of corn yield perunit area as estimated by MODIS andstatistical data released by the US
Department of Agriculture.

Values estimated by this method closely coincide with statestatistical values released by the US Department of Agriculture;
it was possible to quantitatively assess the poor harvests in2002 and 2012, when crops were damaged by record droughts.

25

Research Overview in FY2013
based system that uses MODIS images for viewing global
agro-environmental changes, and GSPAC, a versatile
ecosystem spatial information platform for Asia-wide
spatial data including cropland, climate, and phenology.
These were integrated into SGEMS.

Xバンドの後方散乱係数 σ0 (dB)-10

CSK2009r = 0.73***(n = 128)

CSK2010-12

TSX2011

TSX2012

-14
-16
-18
-20

0

200

400

600

800 1000 1200 1400

群落の穂の総重量 (g m-2)

Figure 4-3

Relationship between panicle weight
during the ripening period and backscatter
coefficients obtained from satellite X-band
SAR sensors.

For rice plant communities during the ripening period, we
discovered that the X-band backscatter coefficient σ0 has themost distinct sensitivity to panicle weight.

(2) Collation of agro-environmental information anddevelopment of an integrated database
Research background
Building a corpus of advanced basic research isessential to support the research that NIAES conducts on
the interactions between global environmental change andagricultural activities and on the dynamics and reductionof risks posed by chemical substances in agro-ecosystems.
In this research area, we are building and expanding
individual databases for soil, insects, microorganisms,
weather, and other important components of the agroenvironment, developing further methods of using thisdata, conducting long-term monitoring of radioactive
substances in the agro-environment, and constructing an
integrated database for the centralized provision of agroenvironmental information.
Key results
i. Building and expanding individual databases for soil,
insects, microorganisms, etc.
We used the Comprehensive Soil Classification
System of Japan, First Approximation in carrying out
field studies in the Chubu, Hokuriku, Kinki, Shikoku,
and Kyushu regions; for each prefecture, we prepareda provisional soil map on a 1/200,000 scale. We also
developed an iOS/Android application called “eSoilMap”, which enables people to easily search soil
maps and other soil information in the field, and to edit
and share information by linking photographs, notes, andthe like to soil maps (Figure 4-4).

Figure 4-4 Linkage between“e-SoilMap”and the cloud (Google Drive).
It is possible to edit and save notes, photographs, and other data in the cloud in association with location information, making it simple
to create unique user soil maps.
In order to edit soil map displays and one’s PIN on a PC, it is necessary to install Google Earth (map software for satellite images andother data, which is provided free of charge by the US company Google). Soil maps for display with Google Earth can be downloaded
at no charge from the“Soil Information Viewing System”(http://agrimesh.dc.affrc.go.jp/soil_db/).

26

In the area of microorganisms, we input to databases
457 specimens of diseased pressed leaves, information on
newly collected microorganisms and the microorganisms
in the Microorganism Museum, and added them to“microForce.”
In the field of insects, we input to a database about
4300 aphids, 2500 weevils (including 400 images), andother insects, created portals adapted to various uses in theinsect inventory system, and added subsystem functions
to enhance user convenience.
ii. Radioactive substance monitoring
As part of the monitoring survey for radioactive
cesium (137Cs) and other nuclides in white rice, wheat, andtheir soil (rice paddies and upland fields), which has been
continued nationally since 1957, we completed analysesof 137Cs, 134Cs, and 90Sr in rice, wheat, and soil gathered in2012 from fixed-point observation fields comprising 14
paddies and seven upland fields around the nation. For a
more efficient process in the simple analysis pretreatment
method for 90Sr in flooded paddy samples from the agroenvironment, we created a pretreatment method based ona Sr-selective adsorption resin.
To update the cropland soil radioactive cesium
concentration distribution map, which we had made in
2011, we measured the radioactive Cs concentrations ofsoil and the air dose rates at 29 sites in controlled zones,
and improved the conversion equation that determines
radioactive Cs concentration from air dose rate. In thenext fiscal year we will prepare a distribution map basedon these results.
iii. Construction of an integrated database of agroenvironmental information
Using technology that takes advantage of the internet
to make integrated use of NIAES and outside databases,
we developed and released a browsing system for abotanical specimen information database that combines
the NIAES database and that of Tokyo Metropolitan

University’s Makino Herbarium. From the perspective ofefficiency and improving user utility, we also gathered
information related to policy on database use and publicaccess; policy issues such as treating data as open data andadopting a Creative Commons license were considered.
iv. Development of an integrated environmental impact
assessment (ecobalance assessment) method
To calculate the environmental load imposed by farmwork, we collected data from farmers’ crop calendars andused LCA software to calculate the fuel consumption ofvarious tasks. Based on those amounts, we calculated
the associated CO2, CH4, N2O, NOx, SOx, and NH3emissions. Because the crop calendars we used were
missing information on post-harvest straw management,
as case studies we calculated environmental burdens forfour scenarios: “straw plowed in,” “straw removed,”“straw removed + compost 10 t/ha,” and “straw
removed + compost 20 t/ha,” and compared them. At
the same time, we used the RothC model to calculate
the soil carbon change over a 20-year period, and thendetermined the per-year soil carbon change. We used
these items to obtain the environmental burden values for“global warming,” “acidification,” and “eutrophication”
as follows. For “global warming”, we calculated GHG
emissions by converting emissions of CO2, CH4, andN2O from rice cultivation and soil carbon storage into
CO2 equivalent. For “acidification” we calculated acidic
substance emissions by converting NOx, SOx, and NH3emissions into SO2 equivalent. For “eutrophication” wecalculated nitrogen and phosphorus leaching and surface
runoff (input amounts were 11% and 8.3%, respectively);eutrophication substance emissions were converted toPO4 equivalent. The “global warming” environmental
burden diminished as the amount of compost increased,
but “acidification” and “eutrophication” environmental
burdens increased as the compost amount increased,
thereby revealing differences among types ofenvironmental burden.

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