Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-19-00025
Naru Takayama, Tsuyoshi Kuwana, T. Tamada, K. Ishitsubo, Yozo Ozaki, Ken Tsuruta, Kohtaro Okada, Yusuke Shibata, Kazuki Fujiu, Takahiro Bando
We developed a method to assess heat-stroke risk during exercise in the outdoor environment based on the potential effective sweating ( PES ) . The PES indicates the minimum effective sweating required to maintain a constant body temperature when undertaking an activity in the outdoor environment. It can be calculated easily using observed meteorological data, body size, clothing, and exercise intensity. Additionally, we propose the concept of globe PES ( PES g ) and PES WBGT , which can be measured using portable equipment, such as a wet-bulb globe temperature ( WBGT ) meter. Especially, PES WBGT can be estimated by only WBGT observations. We performed a thermal-load exposure experiment with human subjects in an outdoor urban environment, and compared the three kinds of effective sweating and actual potential sweating. The calculated PES values had deviations of 33.3 - 42.7 % from actual potential sweating. We assessed the risk of heat stroke based on the decrease in a runner’s weight using routine meteorological data observed in recent decades. Calculations were made for start times set at 30-min intervals from 05:00 to 19:00 on August 2 and 9, the dates of the marathon event in the 2020 Summer Olympics in Tokyo. When the start time was set from 9:30 to 11:00, a runner’s weight was estimated to decrease by an average of 7.37 - 7.40 % and a maximum of 8.09 - 8.20 % by the end of the race. A postural movement or convulsion is likely to occur if the runner did not drink water. When the start time was set to 06:00, the weight decrease was predicted to be 6.18 - 7.15 % ; the thermal load at this time was equivalent to that of a 15:00 or 15:30 start time. Thermal loads may be smaller in the early evening than in the early morning. The average wind speed is weaker in the morning than in the afternoon, thereby decreasing the effect of wind on cooling the surfaces of the human body and the road in the morning. Hence, a change in the start time to early morning may not significantly decrease the thermal load.
{"title":"Proposition of heat-stroke risk assessment based on potential effective sweating possible to measure with portable equipment and its application to the Tokyo 2020 Summer Olympic marathon event","authors":"Naru Takayama, Tsuyoshi Kuwana, T. Tamada, K. Ishitsubo, Yozo Ozaki, Ken Tsuruta, Kohtaro Okada, Yusuke Shibata, Kazuki Fujiu, Takahiro Bando","doi":"10.2480/agrmet.d-19-00025","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00025","url":null,"abstract":"We developed a method to assess heat-stroke risk during exercise in the outdoor environment based on the potential effective sweating ( PES ) . The PES indicates the minimum effective sweating required to maintain a constant body temperature when undertaking an activity in the outdoor environment. It can be calculated easily using observed meteorological data, body size, clothing, and exercise intensity. Additionally, we propose the concept of globe PES ( PES g ) and PES WBGT , which can be measured using portable equipment, such as a wet-bulb globe temperature ( WBGT ) meter. Especially, PES WBGT can be estimated by only WBGT observations. We performed a thermal-load exposure experiment with human subjects in an outdoor urban environment, and compared the three kinds of effective sweating and actual potential sweating. The calculated PES values had deviations of 33.3 - 42.7 % from actual potential sweating. We assessed the risk of heat stroke based on the decrease in a runner’s weight using routine meteorological data observed in recent decades. Calculations were made for start times set at 30-min intervals from 05:00 to 19:00 on August 2 and 9, the dates of the marathon event in the 2020 Summer Olympics in Tokyo. When the start time was set from 9:30 to 11:00, a runner’s weight was estimated to decrease by an average of 7.37 - 7.40 % and a maximum of 8.09 - 8.20 % by the end of the race. A postural movement or convulsion is likely to occur if the runner did not drink water. When the start time was set to 06:00, the weight decrease was predicted to be 6.18 - 7.15 % ; the thermal load at this time was equivalent to that of a 15:00 or 15:30 start time. Thermal loads may be smaller in the early evening than in the early morning. The average wind speed is weaker in the morning than in the afternoon, thereby decreasing the effect of wind on cooling the surfaces of the human body and the road in the morning. Hence, a change in the start time to early morning may not significantly decrease the thermal load.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2480/agrmet.d-19-00025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-19-00033
Wonsik Kim, H. Seo, D. Komori, Jaeil Cho
Using eddy covariance ( EC ) measurements, exchanges of energy, water, and carbon dioxide between the atmosphere and terrestrial ecosystem have been studied worldwide. EC measurements fundamentally operate under the hypotheses of stationarity and ergodicity. However, these hypotheses are disturbed in the real world by various factors generated by varying atmospheric and land surface conditions. The relative sampling error ̶ a parameter quantifying this disturbance estimated by the average convergence in a time series ̶ from a tangerine orchard is investigated to determine its range in the real world, and its capabilities as a quality parameter for EC measurements. Our results showed that the relative sampling error ranges from 5 % to infinity and displays a close relationship with the integral turbulence characteristic as a function of atmospheric stability. Therefore, we suggest that the relative sampling error represents a quality parameter for EC measurements and can be a weighting factor for statistical aggregations of exchanges observed by EC measurements.
{"title":"Characteristics of the relative sampling error and its application to flux aggregation in eddy covariance measurements","authors":"Wonsik Kim, H. Seo, D. Komori, Jaeil Cho","doi":"10.2480/agrmet.d-19-00033","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00033","url":null,"abstract":"Using eddy covariance ( EC ) measurements, exchanges of energy, water, and carbon dioxide between the atmosphere and terrestrial ecosystem have been studied worldwide. EC measurements fundamentally operate under the hypotheses of stationarity and ergodicity. However, these hypotheses are disturbed in the real world by various factors generated by varying atmospheric and land surface conditions. The relative sampling error ̶ a parameter quantifying this disturbance estimated by the average convergence in a time series ̶ from a tangerine orchard is investigated to determine its range in the real world, and its capabilities as a quality parameter for EC measurements. Our results showed that the relative sampling error ranges from 5 % to infinity and displays a close relationship with the integral turbulence characteristic as a function of atmospheric stability. Therefore, we suggest that the relative sampling error represents a quality parameter for EC measurements and can be a weighting factor for statistical aggregations of exchanges observed by EC measurements.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2480/agrmet.d-19-00033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69169855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-19-00039
Tomoki Mochizuki, S. Takanashi, R. Wada, Y. Miyazaki, T. Nakano, A. Tani
Monoterpenes and isoprene emitted from forest ecosystems contribute to the formation of secondary organic aerosols (SOAs) and photochemical oxidants (Ox) and affect an ecosystem’s carbon budget. Initial oxidation products of isoprene, methacrolein (MACR) and methyl vinyl ketone (MVK), are key intermediate compounds for the formation of SOAs and Ox, but the production and loss processes of MACR and MVK and its controlling factors within a forest have not been revealed. To address them within a forest and the behavior of related compounds, we measured vertical concentrations and fluxes of monoterpenes, isoprene, and MACR+MVK in a pine-oak forest during summer. Monoterpene concentrations were the highest near the forest floor. A higher isoprene concentration was observed at the height of the Quercus trees. High positive fluxes of monoterpenes and isoprene were observed during the day. The average flux of isoprene during the measurement period was 2.6 times higher than that of monoterpene. Quercus in the lower layer of the forest can be an important source of isoprene, even though the light intensity was estimated much lower than that of red pine canopy. The MACR+MVK concentrations did not show clear vertical gradient patterns. Both positive and negative MACR+MVK fluxes were observed and large positive MACR+MVK fluxes were occasionally observed under a relatively high O3 concentration and isoprene flux around noon or during the afternoon, suggesting that they are produced more frequently by reaction with reactive species including O3 at a higher temperature. Our results demonstrate that, to investigate sink and source dynamics of MACR+MVK above a forest, it is necessary to separately estimate production rate of MACR+MVK, which depends on isoprene emission from the target and surrounding forests, O3 concentration, temperature, and its deposition rate, which is controlled by its concentration and micrometeorological factors.
{"title":"Canopy fluxes of monoterpene, isoprene and isoprene oxidation products in a pine-oak forest","authors":"Tomoki Mochizuki, S. Takanashi, R. Wada, Y. Miyazaki, T. Nakano, A. Tani","doi":"10.2480/agrmet.d-19-00039","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00039","url":null,"abstract":"Monoterpenes and isoprene emitted from forest ecosystems contribute to the formation of secondary organic aerosols (SOAs) and photochemical oxidants (Ox) and affect an ecosystem’s carbon budget. Initial oxidation products of isoprene, methacrolein (MACR) and methyl vinyl ketone (MVK), are key intermediate compounds for the formation of SOAs and Ox, but the production and loss processes of MACR and MVK and its controlling factors within a forest have not been revealed. To address them within a forest and the behavior of related compounds, we measured vertical concentrations and fluxes of monoterpenes, isoprene, and MACR+MVK in a pine-oak forest during summer. Monoterpene concentrations were the highest near the forest floor. A higher isoprene concentration was observed at the height of the Quercus trees. High positive fluxes of monoterpenes and isoprene were observed during the day. The average flux of isoprene during the measurement period was 2.6 times higher than that of monoterpene. Quercus in the lower layer of the forest can be an important source of isoprene, even though the light intensity was estimated much lower than that of red pine canopy. The MACR+MVK concentrations did not show clear vertical gradient patterns. Both positive and negative MACR+MVK fluxes were observed and large positive MACR+MVK fluxes were occasionally observed under a relatively high O3 concentration and isoprene flux around noon or during the afternoon, suggesting that they are produced more frequently by reaction with reactive species including O3 at a higher temperature. Our results demonstrate that, to investigate sink and source dynamics of MACR+MVK above a forest, it is necessary to separately estimate production rate of MACR+MVK, which depends on isoprene emission from the target and surrounding forests, O3 concentration, temperature, and its deposition rate, which is controlled by its concentration and micrometeorological factors.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2480/agrmet.d-19-00039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69169894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-20-00004
R. Yoshida, S. Fukui, T. Yamazaki
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 scale. The forecast system would be more valuable by considering both the rice growth stage and current meteorological forecast techniques. In this study, we synthesized ensemble numerical weather prediction and a cultivar-based rice growth model to forecast 14-day cold damage risk. The ensemble mean forecast with nine members predicted surface air temperatures more skillfully for seven days with lower root-mean-square errors (RMSEs) (1.3-1.9°C) than those of the climatological forecast (2.1-2.4°C) that is derived from historical observations over 30 years. The single deterministic forecast predicted the temperatures better for five days with 1.3-2.0°C of RMSEs, showing the extension of the predictable period by two days with ensemble forecasting. For the cooling degree-days, both the single and ensemble mean forecasts showed lower RMSEs than the climatological forecast throughout the forecast period of 14 days (4.1, 3.8, and 5.2°C at the forecast time = 14 day for single deterministic, ensemble mean, and climatological forecasts, respectively). Although the climatological forecast estimated the rice growth stages reasonably, the performance for cooling degree-days was inferior to the ensemble mean and single deterministic forecasts. The meteorological mean state is sufficient to estimate the rice growth stage, but an accurate temporal pattern of the surface air temperature provided by numerical weather forecast is essential for reliable cold damage forecasting. Moreover, ensemble forecasting is more effective than the single deterministic forecast to reduce prediction errors for both the surface air temperature and cold damage.
{"title":"Applicability of meteorological ensemble forecasting to predict summer cold damage in rice growth","authors":"R. Yoshida, S. Fukui, T. Yamazaki","doi":"10.2480/agrmet.d-20-00004","DOIUrl":"https://doi.org/10.2480/agrmet.d-20-00004","url":null,"abstract":"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 scale. The forecast system would be more valuable by considering both the rice growth stage and current meteorological forecast techniques. In this study, we synthesized ensemble numerical weather prediction and a cultivar-based rice growth model to forecast 14-day cold damage risk. The ensemble mean forecast with nine members predicted surface air temperatures more skillfully for seven days with lower root-mean-square errors (RMSEs) (1.3-1.9°C) than those of the climatological forecast (2.1-2.4°C) that is derived from historical observations over 30 years. The single deterministic forecast predicted the temperatures better for five days with 1.3-2.0°C of RMSEs, showing the extension of the predictable period by two days with ensemble forecasting. For the cooling degree-days, both the single and ensemble mean forecasts showed lower RMSEs than the climatological forecast throughout the forecast period of 14 days (4.1, 3.8, and 5.2°C at the forecast time = 14 day for single deterministic, ensemble mean, and climatological forecasts, respectively). Although the climatological forecast estimated the rice growth stages reasonably, the performance for cooling degree-days was inferior to the ensemble mean and single deterministic forecasts. The meteorological mean state is sufficient to estimate the rice growth stage, but an accurate temporal pattern of the surface air temperature provided by numerical weather forecast is essential for reliable cold damage forecasting. Moreover, ensemble forecasting is more effective than the single deterministic forecast to reduce prediction errors for both the surface air temperature and cold damage.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-20-00007
Rong Yang, Shiyang Chen
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 farmland in Northwest China, and quantified soil bacterial diversity and composition by using high-throughput DNA sequencing on the Illumina MiSeq platform. Our results showed that maize yield was highest in the pure organic manure treatment and significantly higher than that of the low mineral fertilizer treatment. Organic manure application significantly increased soil nutrient content, while the organic manure level also positively influenced soil nutrient content. Soil bacterial diversity was more sensitive to the application of organic manure than mineral fertilizer. The PERMANOVA results confirmed that bacterial community composition changed along an organic manure level gradient, which was not observed for mineral fertilizer. Organic manure application promoted the abundance of the copiotrophic group, while the environment resistant group were abundant in the only mineral fertilizer treatments. The present study indicated the critical role of organic manure application for increasing crop yield, soil fertility, and soil bacterial diversity while optimizing the community composition of soil bacteria, emphasizing the contribution and importance of organic manure application to overall soil health.
{"title":"Response of soil bacterial community to different fertilization patterns in young oasis farmland","authors":"Rong Yang, Shiyang Chen","doi":"10.2480/agrmet.d-20-00007","DOIUrl":"https://doi.org/10.2480/agrmet.d-20-00007","url":null,"abstract":"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 farmland in Northwest China, and quantified soil bacterial diversity and composition by using high-throughput DNA sequencing on the Illumina MiSeq platform. Our results showed that maize yield was highest in the pure organic manure treatment and significantly higher than that of the low mineral fertilizer treatment. Organic manure application significantly increased soil nutrient content, while the organic manure level also positively influenced soil nutrient content. Soil bacterial diversity was more sensitive to the application of organic manure than mineral fertilizer. The PERMANOVA results confirmed that bacterial community composition changed along an organic manure level gradient, which was not observed for mineral fertilizer. Organic manure application promoted the abundance of the copiotrophic group, while the environment resistant group were abundant in the only mineral fertilizer treatments. The present study indicated the critical role of organic manure application for increasing crop yield, soil fertility, and soil bacterial diversity while optimizing the community composition of soil bacteria, emphasizing the contribution and importance of organic manure application to overall soil health.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-20-00010
Xiang Gao, Fengxue Gu, D. Gong, Weiping Hao, J. Chu, Haoru Li
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 their results with the observed ET using the eddy covariance (EC) method. Generally, the diurnal variation in estimated ET from the three models was similar to that of observed ET by the EC method. However, the PM model significantly underestimated ET. The ET estimates obtained from the SW and PTm models were approximately equal to the observed ET by the EC method. Considering the PTm model’s simplicity, we finally recommend it for rain-fed spring maize fields in the Loess Plateau. After precipitation, the estimated ET from the three models was significantly smaller than measured ET by the EC method, especially the PM model. After a frost, all three models failed to reflect the dramatic decrease in crop transpiration, and thus significantly overestimated ET.
{"title":"Comparison of three evapotranspiration models in a rain-fed spring maize filed in the Loess Plateau, China","authors":"Xiang Gao, Fengxue Gu, D. Gong, Weiping Hao, J. Chu, Haoru Li","doi":"10.2480/agrmet.d-20-00010","DOIUrl":"https://doi.org/10.2480/agrmet.d-20-00010","url":null,"abstract":"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 their results with the observed ET using the eddy covariance (EC) method. Generally, the diurnal variation in estimated ET from the three models was similar to that of observed ET by the EC method. However, the PM model significantly underestimated ET. The ET estimates obtained from the SW and PTm models were approximately equal to the observed ET by the EC method. Considering the PTm model’s simplicity, we finally recommend it for rain-fed spring maize fields in the Loess Plateau. After precipitation, the estimated ET from the three models was significantly smaller than measured ET by the EC method, especially the PM model. After a frost, all three models failed to reflect the dramatic decrease in crop transpiration, and thus significantly overestimated ET.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-19-00032
Ben-Wei Zhu, T. Izuta, Makoto Watanabe
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 N productivity (NP), and mean residence time of N (MRT). The seedlings were grown for one growing season in the potted soil under three N levels (0, 50, and 100 kg N ha) combined with two P levels (0 and 50 kg P ha). Nitrogen supply to the soil reduced NUE by decreasing NP and MRT, whereas P supply enhanced NUE. Although P supply did not have a significant influence on the reduction of NUE with increasing N levels, it affected the response of the NUE components with increasing N levels. Within leaves, N supply reduced the photosynthetic nitrogen use efficiency (PNUE), P alleviated this reduction. Therefore, P is considered as one of the key factors determining the change of NUE in Q. serrata under the influence of high N supply.
氮素利用效率(NUE)被广泛用于评价植物氮素经济性，它被定义为生物量生长与土壤氮素吸收量的比值。以不同土壤氮磷水平下的黑栎(Quercus serrata)幼苗为试验材料，研究不同磷效度下高氮沉降水平对NUE、氮素生产力(NP)和平均停留时间(MRT)的影响。幼苗在3个N水平(0、50和100 kg N ha)和2个P水平(0和50 kg P ha)的盆栽土壤中生长1个生长季节。氮素供应通过降低NP和MRT而降低土壤氮素利用效率，而磷供应则提高土壤氮素利用效率。施磷量对氮肥利用率随施氮量增加而降低的影响不显著，但影响氮肥各组分随施氮量增加的响应。在叶片内，氮素供应降低了光合氮利用效率(pnuue)，施磷缓解了这一降低。因此，磷被认为是决定高氮供给下黑桫椤氮肥利用率变化的关键因素之一。
{"title":"Nitrogen use efficiency of Quercus serrata seedlings under different soil nitrogen and phosphorus supplies","authors":"Ben-Wei Zhu, T. Izuta, Makoto Watanabe","doi":"10.2480/agrmet.d-19-00032","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00032","url":null,"abstract":"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 N productivity (NP), and mean residence time of N (MRT). The seedlings were grown for one growing season in the potted soil under three N levels (0, 50, and 100 kg N ha) combined with two P levels (0 and 50 kg P ha). Nitrogen supply to the soil reduced NUE by decreasing NP and MRT, whereas P supply enhanced NUE. Although P supply did not have a significant influence on the reduction of NUE with increasing N levels, it affected the response of the NUE components with increasing N levels. Within leaves, N supply reduced the photosynthetic nitrogen use efficiency (PNUE), P alleviated this reduction. Therefore, P is considered as one of the key factors determining the change of NUE in Q. serrata under the influence of high N supply.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2480/agrmet.d-19-00032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69169841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.2480/agrmet.d-19-00046
A. Hirata, Y. Kominami, T. Matsui, Y. Hijioka
Solar radiation is an essential parameter for ecological, agricultural, and other models. However, the availability of large-scale radiation data is usually limited. The Mountain Microclimate Simulation Model ( MTCLIM ) can resolve such data insufficiency by estimating missing daily shortwave solar radiation data using simple climatological and topographic parameters. Several studies have found the performance of the MTCLIM to be sufficient for the estimation of solar radiation. However, its performance in the East Asian monsoon zone, which is generally characterized by warm wet summers and cold dry winters, has not been thoroughly evaluated. We assessed the performance of the MTCLIM in Japan located at the East Asian monsoon zone. We estimated daily shortwave solar radiation using daily maximum and minimum temperature and precipitation data recorded over 57 years and topographic parameters including slope angle and direction at 41 meteorological stations. Then, we compared the estimated solar radiation with the solar radiation observed at each meteorological station using a simple linear regression equation. The slope of the regression equation without intercept was 0.96 and the coefficient of determination ( R 2 ) was 0.61 for all data. The estimation performance was increased for the monthly mean of daily solar radiation ( slope=1.03; R 2 =0.93 ) . The degree of estimation error showed geographical and seasonal trends; stations located at higher latitudes had larger slopes than those at lower latitudes. The bias was largest ( positive ) in spring and smallest ( negative ) in summer. This study confirmed that the MTCLIM performed sufficiently well to estimate solar radiation in Japan. In particular, the model’s high performance for the monthly mean of daily solar radiation suggests that it provides estimates of solar radiation that are sufficiently accurate for ecological, agricultural, and other models in which values of average solar radiation for a given period of time are more meaningful than instantaneous daily solar radiation.
{"title":"Evaluation of the estimation of shortwave solar radiation in Japan using the Mountain Microclimate Simulation Model","authors":"A. Hirata, Y. Kominami, T. Matsui, Y. Hijioka","doi":"10.2480/agrmet.d-19-00046","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00046","url":null,"abstract":"Solar radiation is an essential parameter for ecological, agricultural, and other models. However, the availability of large-scale radiation data is usually limited. The Mountain Microclimate Simulation Model ( MTCLIM ) can resolve such data insufficiency by estimating missing daily shortwave solar radiation data using simple climatological and topographic parameters. Several studies have found the performance of the MTCLIM to be sufficient for the estimation of solar radiation. However, its performance in the East Asian monsoon zone, which is generally characterized by warm wet summers and cold dry winters, has not been thoroughly evaluated. We assessed the performance of the MTCLIM in Japan located at the East Asian monsoon zone. We estimated daily shortwave solar radiation using daily maximum and minimum temperature and precipitation data recorded over 57 years and topographic parameters including slope angle and direction at 41 meteorological stations. Then, we compared the estimated solar radiation with the solar radiation observed at each meteorological station using a simple linear regression equation. The slope of the regression equation without intercept was 0.96 and the coefficient of determination ( R 2 ) was 0.61 for all data. The estimation performance was increased for the monthly mean of daily solar radiation ( slope=1.03; R 2 =0.93 ) . The degree of estimation error showed geographical and seasonal trends; stations located at higher latitudes had larger slopes than those at lower latitudes. The bias was largest ( positive ) in spring and smallest ( negative ) in summer. This study confirmed that the MTCLIM performed sufficiently well to estimate solar radiation in Japan. In particular, the model’s high performance for the monthly mean of daily solar radiation suggests that it provides estimates of solar radiation that are sufficiently accurate for ecological, agricultural, and other models in which values of average solar radiation for a given period of time are more meaningful than instantaneous daily solar radiation.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69169983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-10DOI: 10.2480/agrmet.d-19-00006
K. Okada, K. Takagi, Yui Nishida
Over a period of 9 years covering both disturbed and undisturbed periods, we evaluated long-term variations in water and light use efficiency (WUE, LUE) in a cool-temperate mixed forest in northern Hokkaido, Japan: our study clarified the relationship of WUE and LUE to environmental and vegetation variables. WUE and LUE markedly decreased after deforestation: they were negatively correlated with the seasonal variations in photosynthetically active radiation (PAR) and water vapor deficit, and LUE increased with the increase in the leaf area index (LAI) coincident with the vegetation recovery. Other environmental and vegetation variables did not explain the changes in the WUE and LUE. The effect of clear-cutting on LUE was well explained by the change in the LAI; on the other hand, vegetation composition (developed forest or young tree seedling with dense undergrowth) had little effect on the magnitude and variation of LUE. In contrast, the change in LAI had little effect on WUE, because WUE is more sensitive to the atmospheric water deficit than it is to vegetation structure.
{"title":"Effects of forestry management and environmental factors on water and light use efficiencies in a cool-temperate mixed forest in northern Japan","authors":"K. Okada, K. Takagi, Yui Nishida","doi":"10.2480/agrmet.d-19-00006","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00006","url":null,"abstract":"Over a period of 9 years covering both disturbed and undisturbed periods, we evaluated long-term variations in water and light use efficiency (WUE, LUE) in a cool-temperate mixed forest in northern Hokkaido, Japan: our study clarified the relationship of WUE and LUE to environmental and vegetation variables. WUE and LUE markedly decreased after deforestation: they were negatively correlated with the seasonal variations in photosynthetically active radiation (PAR) and water vapor deficit, and LUE increased with the increase in the leaf area index (LAI) coincident with the vegetation recovery. Other environmental and vegetation variables did not explain the changes in the WUE and LUE. The effect of clear-cutting on LUE was well explained by the change in the LAI; on the other hand, vegetation composition (developed forest or young tree seedling with dense undergrowth) had little effect on the magnitude and variation of LUE. In contrast, the change in LAI had little effect on WUE, because WUE is more sensitive to the atmospheric water deficit than it is to vegetation structure.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47653030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-01DOI: 10.2480/agrmet.d-19-00013
K. Itakura, F. Hosoi
Leaf area is one of the most important elements of information in plant management. Leaf area is associated with many agronomic and physiological processes including growth, photosynthesis, transpiration, photon interception, and energy balance. Three-dimensional ( 3D ) plant architecture is required for monitoring, since plants have three-dimensionally complex structures. A photogrammetric approach called structure from motion ( SfM ) was used for the 3D measurement. A method using the total area of a horizontal face of voxels could possibly be employed to estimate leaf area in 3D plant images. However, the leaf inclination angle of each small part, the voxel size, and misconfigured voxels in a vertical direction near leaf surfaces should be considered in the calculation. We propose a method for leaf area estimation in voxel-based models that overcomes these problems of estimation error. Using our method, the leaf area was estimated with an absolute error of 8.87 % . This result was obtained by fully utilising 3D information such as voxel size and leaf inclination angle at each voxel. Moreover, our method does not involve manual operations for its construction, unlike a previous method. From the perspectives of high degrees of accuracy and automatic procedures, this voxel-based leaf area calculation method is advantageous.
{"title":"Voxel-based leaf area estimation from three-dimensional plant images","authors":"K. Itakura, F. Hosoi","doi":"10.2480/agrmet.d-19-00013","DOIUrl":"https://doi.org/10.2480/agrmet.d-19-00013","url":null,"abstract":"Leaf area is one of the most important elements of information in plant management. Leaf area is associated with many agronomic and physiological processes including growth, photosynthesis, transpiration, photon interception, and energy balance. Three-dimensional ( 3D ) plant architecture is required for monitoring, since plants have three-dimensionally complex structures. A photogrammetric approach called structure from motion ( SfM ) was used for the 3D measurement. A method using the total area of a horizontal face of voxels could possibly be employed to estimate leaf area in 3D plant images. However, the leaf inclination angle of each small part, the voxel size, and misconfigured voxels in a vertical direction near leaf surfaces should be considered in the calculation. We propose a method for leaf area estimation in voxel-based models that overcomes these problems of estimation error. Using our method, the leaf area was estimated with an absolute error of 8.87 % . This result was obtained by fully utilising 3D information such as voxel size and leaf inclination angle at each voxel. Moreover, our method does not involve manual operations for its construction, unlike a previous method. From the perspectives of high degrees of accuracy and automatic procedures, this voxel-based leaf area calculation method is advantageous.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43305722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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