Methane (CH4) produced in rice-paddy soil is transported to the atmosphere either via the rice plants or by bubbling events (ebullition); however, little is known about the frequency and intensity of bubbling CH4 emissions and the factors that affect them. We developed a method to quantify ebullition using high-time-resolution (~1 Hz) CH4 concentration data obtained by closed-chamber measurements.

Climate change may induce severe frost damage to crops, and thus a reasonable assessment of frost risk, considering both crop phenology and meteorology, is required. Here, we introduced a new index of potential frost risk (Frisk) using thermal time (minimum air temperature below the threshold value) weighted by the percentage of budburst (Pbud). Moreover, we evaluated the spatiotemporal distributions

In Lao PDR (People’s Democratic Republic), rice is one of the major staple crops planted in more than 80% of the cultivated areas. We attempted to evaluate the adaptation preference of the farmers in Laos through a climate change adaptation survey approach. The eight adaptations including irrigation, nitrogen fertilizer application rates, transplanting date shifting were first assessed by the CERES‑Rice

The effects of continuous lighting (CL) before gene transfer on leaf biomass, leaf hemagglutinin (HA) content per biomass, and leaf HA content per plant in Nicotiana benthamiana after gene transfer were investigated in a transient gene expression system. A control photoperiod of 16 h d-1 and an extended photoperiod of 24 h d-1 were compared at two photosynthetic photon flux density (PPFD) levels of

The increasing amount of measurement data on land-atmosphere flux has made it possible to assess the interannual and longer processes that are driven by environmental change and disturbance of terrestrial ecosystems. In this study, I used a global dataset of carbon dioxide (CO2) fluxes at eddy-covariance tower sites (FLUXNET2015) to investigate long-term trends of net ecosystem CO2 exchange (NEE),

Root respiration (Rr) plays a crucial role in the global carbon balance, because Rr accounts for about a half of soil respiration in typical forest ecosystems. Plant roots are different in metabolism and functions according to size. Fine roots, which are typically defined as roots < 2 mm in diameter, perform important ecosystem functions and consequently govern belowground carbon cycles mainly because

Crop yield is mainly affected by climatic factors such as temperature and precipitation. Besides these factors, improved seeds, irrigation access, and fertilizers also affect yield. In the present study, we collected crop yield data for major crops such as maize, rice, and wheat from the Koshi River Basin, Nepal. We investigated the yield trends over 30 years (1987‑2016) and related the yields with

Spring phenology is essential in modeling the carbon balance of high‑latitude ecosystems and is possibly sensitive to climate change. In the present study, we evaluated the onset of the growing season for three species (paper birch, bog blueberry, and bog Labrador tea) in interior Alaska from 2012 to 2019 using photos taken using time‑lapse cameras. We also evaluated the onset of the growing season

Use of information and communication technologies, as well as robotics, routinely saves labor and refines agricultural tasks; thus, innovative “smart farming” to maintain and enhance the quality of crops can improve the sustainability of agriculture. When managing crop growth using remote‑sensing drones, the normalized difference vegetation index (NDVI)—used to assess growth—typically changes depending

Leafy vegetables cultivated in greenhouses during the winter are sometimes exposed to cold air from outside the greenhouse to enhance sugar and nutrient content. To analyze the possible involvement of photosynthetic and respiratory activities in this process, we evaluated the gas-exchange activity of spinach (Spinacia oleracea L.) plants cultivated in an unheated greenhouse in mid-winter in Sapporo

In cool climates, low temperature is critical for growth and yield of sweet potato (Ipomoea batatas L.). Despite its negative effects, few studies have quantified the impact. We evaluated effects of soil temperature (Ts) on growth and yield in sweet potato from 2-year field trials in northern Japan. Ts was controlled by three steps using plastic mulch at different colors (green, black and white) with

This study was conducted to analyze the effectiveness of using reflective mulch under the stands of oil palm plants of several ages on the intensity of solar radiation reflection, growth, chlorophyll content, and photosynthetic characteristics of soybeans. A nested design was used, with the first factor of oil palm age group consisting of open land and land under oil palm stands aged 4, 5, and 8 years

Rice is the most important cereal crop in Japan, and therefore the impact of projected climate change on its production and quality has been assessed using rice growth models accounting for the effects of rising temperature and atmospheric CO2 concentration ([CO2]) on important growth processes. Recent experimental studies, however, have shown some negative effects of interactions between [CO2] and

The statistical characteristics of 1789 deaths, 1552 injuries and 1904 disasters caused by lightning based on the 2009 to 2018 National Lightning Disaster Compilation of mainland China were analyzed. The results showed that males accounted for 53% of casualties. Lightning disasters were more common in the east and south than in the west and north. The number of lightning disasters and casualties in

Manually operated closed-chamber methods have been used extensively to measure CH4 emissions from rice paddies, but the long chamber deployment time (e.g., 30 min), together with the labor required for gas sampling and subsequent analysis by gas chromatography severely limit their usefulness for multiple, high-throughput measurements. The objective of this study was to develop a modified closed-chamber

AsiaFlux (http://www.asiaflux.net/) was established in 1999 as the Asian arm of FLUXNET, the worldwide flux network, to develop collaborative research and data sets on the cycles of carbon and water in key ecosystems in Asia, to organize workshops and training on current and related global change themes, and to cultivate next generation scientists to be informed leaders with skills and perspectives

The eddy covariance (EC) technique-based observation system allows for researchers to determine latent and sensible heat fluxes, which are key components of the surface energy balance. The number of water and energy flux studies in Asia has increased as the number of flux measurement sites and the length of the observation periods have grown. To retrace the footprints of the AsiaFlux network and predict

Soil respiration (Rs) is the largest flux of carbon dioxide (CO2) next to photosynthesis in terrestrial ecosystems. With the absorption of atmospheric methane (CH4), upland soils become a large CO2 source and CH4 sink. These soil carbon (C) fluxes are key factors in the mitigation and adaption of future climate change. The Asian region spans an extensive area from the northern boreal to tropical regions

To elucidate the dynamic features of carbon sequestration in ecosystems under changing climates and various disturbance regimes, researchers must understand key ecosystem processes, such as carbon allocation and partitioning, organic matter decomposition, and nutrient cycles, as well as plant functional traits. Here, we reviewed the existing literature and conducted meta-analyses using available datasets

Many VOCs are reactive in the atmosphere, may produce secondary organic aerosol (SOA), and keep photochemical ozone concentrations high by VOC-involved reactions. Accumulated studies have shown the importance of terrestrial ecosystems which can be sinks and sources of VOCs. The research progress in the exchange of volatile organic compounds (VOCs) between terrestrial ecosystems and the atmosphere was

A wide variety of models have been developed and used in studies of land-atmosphere interactions and the carbon cycle, with aims of data integration, sensitivity analysis, interpolation, and extrapolation. This review summarizes the achievements of model studies conducted in Asia, a focal region in the changing Earth system, especially collaborative works with the regional flux measurement network

Neural network (NN) models with environmental data and the extent of ventilator openings as inputs have the potential to estimate the number of air exchanges per hour (N) in real time of a naturally ventilated greenhouse. In this study, the intraseasonal and interseasonal applicability of an NN model was verified: whether the model trained in a specific period can be applied to different periods of

Accurate estimates of the rain-fed field evapotranspiration (ET) in the Loess Plateau of Northwest China is critical for predicting hydrologic processes, crop yield formation, and climate change. We simulated the ET variation in a rain-fed spring maize field in the eastern Loess Plateau using the Penman-Monteith (PM), Shuttleworth-Wallace (SW), and modified Priestley-Taylor (PTm) models. Then we compared

Interactions between boundary layer wind and topography form non-uniform air temperature distributions in cold and snow-covered regions. Because of this heterogeneity, spatially interpolated air temperatures sometimes deviate from observed values. To evaluate the quality of spatially interpolated daily mean temperatures (Tint) provided by a 1 km gridded meteorological data service (Ohno et al., 2016)

Ophiorrhiza pumila is a medicinal plant distributed on the floors of humid inland forests in subtropical areas and accumulates camptothecin (CPT) in whole plant organs. To elucidate the proper light and air temperature conditions for plant growth and CPT yield, we conducted two experiments under controlled environments. In experiment 1, we measured the net photosynthetic rate (Pn) and transpiration

We constructed 3D models of the greenhouse (168 m2) and tomato plants (plant height: 150 cm). The point cloud data of tomato plants was acquired by a 3D scanner and converted to the 3D model, which was constructed using polygons. The canopy 3D model was installed in the greenhouse 3D model. In addition, the date, time, latitude, longitude, global solar radiation, and optical properties of objects,

To understand the magnitudes of temporal variation in soil respiration (Rs) and its spatial heterogeneity, and the effect of abiotic and biotic factors to cause the variation in a young plantation recovering after the clear-cutting of a mature forest, we analyzed 8 year Rs, microclimate, and vegetation data obtained in a young hybrid larch plantation with dense undergrowth of dwarf bamboo Sasa in northern

Abrupt temperature drops pose serious concerns for rice production in northern Japan. Previous early warning systems have been based on projected temperature tendencies, and alerts have announced for the occurrence of low temperatures. The rice crop has low-temperature-sensitive stages; however, previous systems have not considered them because of the difficulty of simulating rice growth at the local

Fertilization in farming systems should not only optimize crop yields and soil fertilizer but also maintain soil biodiversity and functions. In young oasis farmland, knowledge regarding soil bacteria respond to fertilization strategies is very limited. We performed a 12-year field experiment to evaluated the effects of organic manure, mineral fertilizer and their combination on a typical young oasis

The mitigation of the urban heat island effect is an important environmental issue for sustainable urban development. We quantified the relative contributions to surface cooling associated with land use changes from an urban center to an urban park using the temperature decomposition method, with one-year paired eddy covariance measurements in Sakai, Japan. The enhanced heat transport efficiency achieved

Nitrogen use efficiency (NUE), defined as the ratio of biomass growth and the nitrogen (N) taken up from a soil, is widely used in the evaluation of plant N economy. We conducted a fertilization experiment with Quercus serrata seedlings under different soil N and phosphorus (P) levels to determine the influence of high N deposition levels under different P availabilities upon NUE, plus the NUE components

The irradiance of solar radiation in a greenhouse with a complex structure was calculated using a diagram for sky view factor (DSVF) and compared with observed values. Structural materials (such as side pillars and rafters) and non-structural materials (such as lock channels, door frames, and ventilation fans) were treated as sunshine obstacles, including lower rafters and equal leg angles in the inner

Wheat is one of the world’s most important crops, and its phenological model is useful for scheduling agricultural practices such as fungicide or fertilizer application. Although various wheat phenological models have been developed throughout the world, a conventional model-mostly used for Japanese cultivars-is one wherein temperature and daylength responses are expressed as sigmoidal and exponential

Trace atmospheric gases in the biosphere, such as ozone (O3), nitrogen oxides (NOx), and biogenic volatile organic compounds (BVOCs), can affect the carbon cycle as well as the climate. Vertical profiles of nitric oxide (NO), O3, and volatile organic compound (VOC) concentrations were measured at a Japanese larch (Larix kaempferi) forest in the foothills of Mt. Fuji in Japan over an 11-day period in

We compared the difference of heatstroke risk of marathon runners in the Summer Olympics on the basis of the percentage of weight decrease due to sweating using potential effective sweating, between Tokyo and Sapporo For the women's marathon, the difference in the rate of decrease in body weight was 0 42 when the start time was 11 : 00, with 7 51 loss for Tokyo and 7 09 for Sapporo Nevertheless, when

Ozone (O3) is an air pollutant that negatively affect carbon budget in woody plants. In the present study, we aimed to clarify the effects of ozone on soil respiration rate of Siebold’s beech seedlings (Fagus crenata) grown under different soil-nutrient conditions. Seedlings were grown under three levels of O3 fumigation (charcoal-filtered air or O3 at 1.0 or 1.5 times ambient concentration) in combination

Sky view factor (SVF) is a ratio of sky in upper hemisphere and is an important index for many environmental studies. Frequently used method for measuring SVF is taking fisheye image of upper hemisphere by a camera with fisheye lens (Nikon FC-E8 and FC-E9). In this study, we devised the usage of a spherical camera (RICOH Theta S), which can takes a picture with 360° field of view (FOV), for SVF measurement

To characterize the deposition of long-range transported particulate matter (PM) on the foliar surface of Japanese forest trees, we periodically collected the PM deposited on the needle surface of mature Japanese cypress (Chamaecyparis obtusa) grown in the mountainous area of Nagasaki located in the western region of Japan from 24 April to 30 October, 2017. Metal element compositions and concentration

Predicted climate changings can affect hemi-boreal forests especially for soil conditions with low water-holding capacity and susceptibility to soil water deficits. In our study, species-specific sap flux, transpiration and water use efficiency of growth (WUE) were investigated at a mixed hemi-boreal forest ecosystems, especially during temporary moderate dry periods in the main growing season. Therefore

Desert ecosystems exposed to extreme droughts are vulnerable to climate change. Multi-scale mechanism of hydrological adaptation of desert plants to drought are not fully understood, creating uncertainty in risk assessment of desert ecosystems to climate change by ecological modelling. In this study, we investigated multi-scale water use strategies of Haloxylon ammodendron, a dominant desert shrub

Recently, Moso bamboo forests have been expanding in Japan because they were left unmanaged and because of the characteristically fast growth rate of bamboo. In this study, trees of 14 bamboo species in two bamboo forests and an exhibition garden in Japan were screened for biogenic volatile organic compound (BVOC) emissions by using a leaf cuvette. The screening showed that 12 out of 14 species (86%)

To examine growth conditions that can increase the critical dietary mineral zinc in leaves of baby leaf red oak lettuce, we investigated zinc accumulation under various conditions, including different zinc concentrations in nutrient solution, wind speeds, and root zone temperatures. A high zinc concentration in the nutrient solution led to greatly increased leaf zinc concentration, but also decreased

To clarify the effects of ozone (O3) on the resistance of Japonica rice (Oryza sativa L.) to root lodging, the Japanese major rice cultivar Koshihikari was exposed to four levels of O3 in open-top chambers (mean O3 concentration: 17.3, 32.4, 51.1, and 66.3 nl l). We evaluated the resistance to root lodging by measuring pushing resistance at 15 days after heading (DAH) and the dry masses of plant organs

Agricultural drought frequently occurs and results in major grain yield loss in semi-arid climate region, but determining it is difficult. This study was conducted to determine agricultural drought for spring wheat (Triticum aestivum L.) in the western Loess Plateau of China. Several statistical models were established and evaluated by long-term data, including soil water in soil layer of 50 cm depth

Year-round eddy covariance flux measurements were made in a semiarid grassland in Mongolia during 20092014 to examine the interannual variability in net ecosystem CO2 exchange (NEE) and its climatic controls. Annual cumulative NEE ranged from -20.9 to 8.1 g C m yr, indicating that the semiarid grassland ecosystem can be a carbon source or a carbon sink, depending on climatic conditions. A correlation

To increase Japanese soybean yield, both practical and genetic improvements are needed. Early sowing improved yields in the United States, where indeterminate cultivars may produce better yields than determinate cultivars, particularly with early sowing. However, the mechanism for the yield response is not fully understood. Furthermore, whether these results are valid for cool regions in northern Japan

Lidar (light detection and ranging) has been widely utilized for estimating the structural parameters of plants, such as tree height, leaf inclination angle, and biomass. However, individual trees have been primarily manually extracted from three-dimensional (3D) point cloud images. Automatically detecting each tree and analyzing its structural parameters is desirable. In this study, we propose a method

Tropospheric ozone (O3) concentration has been increasing. The aim of this study was to compare the effect of O3 exposure on monoterpene emission rate and the components of Japanese cedar (Cryptomeria japonica) between three major gene pools identified by population genetic structure analysis. At the O3-FACE (Free-Air O3 and CO2 Enrichment) facility, 1-year saplings of three clones of Japanese cedar

Th e purposes of this research were to increase artificial rainfall and evaluate the area affected by artificial rainfall. The experiment involved the seeding of liquid carbon dioxide at a height of 2500 m with a seeding rate of 11.1 g/s for 6 min around Karatsu, Saga, Japan on Dec. 26, 2013. The height of the cloud increased significantly, and a virga was observed under the cloud bottom at 2100 m

Crop coefficient (Kc) is a very useful and widely used variable in evapotranspiration estimation in cropland. Traditional methods in calculating Kc are based on field water balance, which is limited by long measurement interval and small study area. In addition, there is the need for Kc under new agronomy practice such as plastic mulching and drip irrigation in arid environments. This study calculated

Rice is the most important crop in Lao People’s Democratic Republic (Lao PDR). The improvement of its productivity is strongly recommended, but information about its growth characteristics in farmers’ fields is limited. This study evaluated the dynamics of the leaf area index (LAI) and analyzed the relationship between the rice productivity and soil in farmers’ fields in Vientiane province, Lao PDR

To investigate the short-term effects of grassland renovation on carbon dioxide (CO2) exchange of intensively managed grasslands in Japan, we conducted CO2 flux measurements during the renovation process by using the eddy covariance and closed chamber methods in 2007, 2012, and 2013. The flux measurements were conducted at three grassland fi elds: two fi elds used for cutting, one receiving only chemical

Methods have been developed and evaluated to collect Cs in stemflow to investigate the possibility of secondary radiocaesium contamination via stemflow in Japanese persimmon (Diospyros kaki Thumb.) orchards. Collection pads were made by encapsulating sphagnum or absorbent cotton in a tea pack (polyester-polyethylene composite fiber). In addition, stemflow was collected directly by a plastic zipper

Human population growth has led to increases in energy and food production, use of fertilizers, and wastewater flows. Enhanced availability of nitrogen is a cause of eutrophication of rivers, lakes, and estuaries worldwide. In this study, Citarum River Basin, West Java, Indonesia was selected as a target area, supplying 80% of domestic water to Jakarta Metropolis. Meteorological and hydrological data

Genotypes with high potential yield would improve crop production. Trials that examined potential yield have been conducted around the world, producing databases that can be mined to reveal “hidden” high-yield cultivars. However, yield data from different times and locations are not comparable because yield integrates the effects of cultivar-specific potential with the effects of weather and management

Photosynthetically assimilated carbon (C) is transported from source leaves to fruits depending on their development stage. To examine the translocation of the assimilated C in a shoot with a fruit throughout the development process, we constructed an in-situ CO2 exposure chamber system for a fruit-bearing apple shoot and measured the assimilation of C in leaves and its translocation to the fruit in

Quercus species occur widely in East Asia and are major tree species in Japan. The ground-grown seedlings of Quercus serrata and Quercus mongolica var. crispula were exposed to enriched ozone (ambient + 40 ppbv) over one growing season by using open-top-chambers (OTC), and isoprene emissions from the two tree-species were measured across a growing season by using the leaf cuvette method. The isoprene

Drought and high temperature stress are the major limitation for the crop productions. Proline as osmoregulator in wheat plant under these stresses was studied through field experiments. The experimental design was randomized complete block with four factors i.e. the environment (2008-09 and 2009-10), sowing management (Planting windows PW’s; PW1, PW2, PW3, PW4 and PW5), genotypes (Chakwal-50, Wafaq-2001

Leaf litter decomposition strongly affects the global carbon cycle through carbon dioxide (CO 2) emissions to the atmosphere. The litter bag method (LB) and chamber method with litter addition and removal treatments (C-LART) have been used to quantify the litter decomposition rate and its resultant CO2 flux. The C-LART method measures soil CO2 fluxes in control, litter addition, and litter removal

To mitigate CH4 emission from paddy fields, accelerating the decomposition of the incorporated rice straw during the fallow season would be a practical strategy. Various ways to accelerate the straw decomposition rate have been proposed, but their effectiveness in cold regions has not been confirmed. In this study, the use of shallow autumn tillage to incorporate straw in the soil and its potential