Pub Date : 2022-07-10DOI: 10.2480/agrmet.d-21-00051
K. Tatsumi
{"title":"Rice yield reductions due to ozone exposure and the roles of VOCs and NOx in ozone production in Japan","authors":"K. Tatsumi","doi":"10.2480/agrmet.d-21-00051","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00051","url":null,"abstract":"","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46728002","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 : 2022-07-10DOI: 10.2480/agrmet.d-22-00008
K. Fujiwara, S. Kubo, Kensuke Eijima, R. Matsuda, A. Yano
{"title":"Improved LED artificial sunlight source system available for sunlight-effect research in plant sciences","authors":"K. Fujiwara, S. Kubo, Kensuke Eijima, R. Matsuda, A. Yano","doi":"10.2480/agrmet.d-22-00008","DOIUrl":"https://doi.org/10.2480/agrmet.d-22-00008","url":null,"abstract":"","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46788065","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 : 2022-01-10DOI: 10.2480/agrmet.d-21-00038
Yuanhao CHEN, Ryo MATSUDA, Kazuhiro FUJIWARA
Phosphor-converted white LEDs (PCW-LEDs) of numerous types with different relative spectral photon-flux-density distributions (SPDs) are commercially available today. Some are regarded as promising light sources for use in plant factories with artificial lighting. The leaf net photosynthetic rate (Pn) measured under PCW-LED light is an important criterion for evaluating PCW-LEDs in terms of photosynthesis performance. To ascertain Pn rapidly under dozens of PCW-LED lights having different SPDs, we have developed a rapid and semi-automated Pn-quantification method. The method uses a modified LED-artificial sunlight source system (LASS system) and a Pn-measurement system. The modified LASS system can produce light with an SPD, which can accurately approximate that of any PCW-LED light at a photosynthetic photon flux density (PPFD) of 150 μmol m-2 s-1. First, PCW-LED lights of 30 types at a PPFD of 150 μmol m-2 s-1 were produced using the modified LASS system within 2.5 h. We then measured the Pn of cos lettuce, red-leaf lettuce, and green-leaf lettuce (Lactuca sativa L.) plants. In a 16-h Pn measurement repetition, the modified LASS system supplied all the produced lights automatically and successively to an identical leaf of a lettuce plant. A Pn-measurement system simultaneously measured Pn under the produced light. Results show that the mean Pn values of the cos lettuce, red-leaf lettuce, and green-leaf lettuce under the 30 produced lights at 20 days after sowing were, respectively, 7.11-8.02, 5.76-7.11, and 4.83-6.17 μmol m-2 s-1. A rapid and semi-automated method was developed for successive measurement of Pn under dozens of combined lights, of which each SPD approximated that of the selected PCW-LED lights, within days, which indicates that the method can determine the Pn quickly under numerous PCW-LED lights. Results show that the system contributes to rapid selection of PCW-LED lights performing high Pn.
{"title":"Rapid and semi-automated leaf net photosynthetic rate determination for numerous phosphor-converted white-LED lights of different spectral distributions","authors":"Yuanhao CHEN, Ryo MATSUDA, Kazuhiro FUJIWARA","doi":"10.2480/agrmet.d-21-00038","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00038","url":null,"abstract":"Phosphor-converted white LEDs (PCW-LEDs) of numerous types with different relative spectral photon-flux-density distributions (SPDs) are commercially available today. Some are regarded as promising light sources for use in plant factories with artificial lighting. The leaf net photosynthetic rate (<i>P</i><sub>n</sub>) measured under PCW-LED light is an important criterion for evaluating PCW-LEDs in terms of photosynthesis performance. To ascertain <i>P</i><sub>n</sub> rapidly under dozens of PCW-LED lights having different SPDs, we have developed a rapid and semi-automated <i>P</i><sub>n</sub>-quantification method. The method uses a modified LED-artificial sunlight source system (LASS system) and a <i>P</i><sub>n</sub>-measurement system. The modified LASS system can produce light with an SPD, which can accurately approximate that of any PCW-LED light at a photosynthetic photon flux density (PPFD) of 150 μmol m<sup>-2</sup> s<sup>-1</sup>. First, PCW-LED lights of 30 types at a PPFD of 150 μmol m<sup>-2</sup> s<sup>-1</sup> were produced using the modified LASS system within 2.5 h. We then measured the <i>P</i><sub>n</sub> of cos lettuce, red-leaf lettuce, and green-leaf lettuce (<i>Lactuca sativa</i> L.) plants. In a 16-h <i>P</i><sub>n</sub> measurement repetition, the modified LASS system supplied all the produced lights automatically and successively to an identical leaf of a lettuce plant. A <i>P</i><sub>n</sub>-measurement system simultaneously measured <i>P</i><sub>n</sub> under the produced light. Results show that the mean <i>P</i><sub>n</sub> values of the cos lettuce, red-leaf lettuce, and green-leaf lettuce under the 30 produced lights at 20 days after sowing were, respectively, 7.11-8.02, 5.76-7.11, and 4.83-6.17 μmol m<sup>-2</sup> s<sup>-1</sup>. A rapid and semi-automated method was developed for successive measurement of <i>P</i><sub>n</sub> under dozens of combined lights, of which each SPD approximated that of the selected PCW-LED lights, within days, which indicates that the method can determine the <i>P</i><sub>n</sub> quickly under numerous PCW-LED lights. Results show that the system contributes to rapid selection of PCW-LED lights performing high <i>P</i><sub>n</sub>.\u0000</p>","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534270","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 : 2022-01-10DOI: 10.2480/agrmet.d-21-00033
Masako KAJIURA, Takeshi TOKIDA
A modified closed-chamber method for estimating total, plant-mediated, and bubbling (ebullition) emissions of CH4 from rice paddies has been developed to use high-time-resolution CH4 concentration data (~1 Hz) obtained by a spectroscopic mobile gas analyzer. Here we aimed at determining an appropriate minimum time length of chamber closure for accurate flux measurement by investigating 3255 datasets obtained from a 2-year field survey. To investigate the minimum time length for each chamber measurement, we generated a series of datasets from each measurement: by setting the hypothetical termination time of the chamber closure ahead in 1-min intervals, we obtained various chamber CH4 concentration time series with different durations of chamber closure, and separately estimated CH4 emissions via rice plants and bubbling from each. The estimated flux was sensitive to time length with short closure times, but became less sensitive with longer closure. We defined the minimum time length at which the difference in estimated flux between adjacent time windows was small enough (<10% of plant-mediated emission). The estimated minimum time length differed from one measurement to another, but 10 min was sufficient for >99% of cases. Detailed analysis showed a positive correlation between minimum time length and frequency of bubbling events; the time length needed to be longer as bubbling events became more frequent. From this relationship, we computed the appropriate chamber-duration time as a function of bubbling frequency. In the absence of ebullition, 4-5 min was sufficient, but as the bubbling frequency increased to 2.5 times per minute 15-20 min was necessary for accurate pathway-dependent flux measurements.
{"title":"Appropriate chamber deployment time for separate quantification of CH4 emissions via plant and ebullition from rice paddies using a modified closed-chamber method","authors":"Masako KAJIURA, Takeshi TOKIDA","doi":"10.2480/agrmet.d-21-00033","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00033","url":null,"abstract":"A modified closed-chamber method for estimating total, plant-mediated, and bubbling (ebullition) emissions of CH<sub>4</sub> from rice paddies has been developed to use high-time-resolution CH<sub>4</sub> concentration data (~1 Hz) obtained by a spectroscopic mobile gas analyzer. Here we aimed at determining an appropriate minimum time length of chamber closure for accurate flux measurement by investigating 3255 datasets obtained from a 2-year field survey. To investigate the minimum time length for each chamber measurement, we generated a series of datasets from each measurement: by setting the hypothetical termination time of the chamber closure ahead in 1-min intervals, we obtained various chamber CH<sub>4</sub> concentration time series with different durations of chamber closure, and separately estimated CH<sub>4</sub> emissions via rice plants and bubbling from each. The estimated flux was sensitive to time length with short closure times, but became less sensitive with longer closure. We defined the minimum time length at which the difference in estimated flux between adjacent time windows was small enough (<10% of plant-mediated emission). The estimated minimum time length differed from one measurement to another, but 10 min was sufficient for >99% of cases. Detailed analysis showed a positive correlation between minimum time length and frequency of bubbling events; the time length needed to be longer as bubbling events became more frequent. From this relationship, we computed the appropriate chamber-duration time as a function of bubbling frequency. In the absence of ebullition, 4-5 min was sufficient, but as the bubbling frequency increased to 2.5 times per minute 15-20 min was necessary for accurate pathway-dependent flux measurements.\u0000</p>","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"163 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534255","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00053
Y. Doi, Yonghee Shin, Wonsik Kim, Jaewon Choi, T. Iizumi
An unstable supply of commodity crops and associated increases in food prices are recent and growing concerns due to increasing temperatures, changing precipitation patterns and increasing frequencies of some extreme climate events. Agricultural monitoring and forecasting can support national food agencies, international organizations and commercial entities in better responding to anticipated production shocks induced by seasonal climate extremes. The global seasonal crop forecasting service jointly developed in 2018 by the National Agriculture and Food Research Organization ( NARO ) , Japan and the Asia-Pacific Economic Cooperation Climate Center ( APCC ) , South Korea is an emerging and unique example of agricultural forecasting tailored to major commodity crops ( maize, rice, wheat and soybean ) . The present study evaluates the skills of the NARO-APCC yield forecasts in five countries located in the Southern Hemisphere ( the 2019/20 season in Australia and Uruguay and the 2018/19 season in Argentina, Brazil and Paraguay ) , following the previous assessment for the 2019 season in Northern Hemisphere countries. The results reveal that the NARO-APCC forecasts can capture the major characteristics of reported state yields even six months before harvesting, with variations by crop ( the correlation coefficients calculated between the forecasted and reported state yields within a country in a season of interest were frequently over 0.8 for maize, rice and wheat and approximately 0.3 for soybean ) . In three-fifths of the 122 crop-state combinations assessed here, the NARO-APCC forecasts showed smaller forecast errors than those of the simple forecasts derived solely based on the reported yields. The findings of this study emphasize the novelty of long-range crop forecasting, such as the NARO-APCC forecasts that provide yield forecast information available even just after planting. Together, the NARO-APCC forecasts and existing regional crop forecasts contribute to making objective yield forecast information more seamlessly available throughout the season from planting to harvesting than what is currently available.
{"title":"Assessing the subnational-level yield forecast skills of the 2019/20 season NARO-APCC Joint Crop Forecasting Service for Southern Hemisphere countries","authors":"Y. Doi, Yonghee Shin, Wonsik Kim, Jaewon Choi, T. Iizumi","doi":"10.2480/agrmet.d-21-00053","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00053","url":null,"abstract":"An unstable supply of commodity crops and associated increases in food prices are recent and growing concerns due to increasing temperatures, changing precipitation patterns and increasing frequencies of some extreme climate events. Agricultural monitoring and forecasting can support national food agencies, international organizations and commercial entities in better responding to anticipated production shocks induced by seasonal climate extremes. The global seasonal crop forecasting service jointly developed in 2018 by the National Agriculture and Food Research Organization ( NARO ) , Japan and the Asia-Pacific Economic Cooperation Climate Center ( APCC ) , South Korea is an emerging and unique example of agricultural forecasting tailored to major commodity crops ( maize, rice, wheat and soybean ) . The present study evaluates the skills of the NARO-APCC yield forecasts in five countries located in the Southern Hemisphere ( the 2019/20 season in Australia and Uruguay and the 2018/19 season in Argentina, Brazil and Paraguay ) , following the previous assessment for the 2019 season in Northern Hemisphere countries. The results reveal that the NARO-APCC forecasts can capture the major characteristics of reported state yields even six months before harvesting, with variations by crop ( the correlation coefficients calculated between the forecasted and reported state yields within a country in a season of interest were frequently over 0.8 for maize, rice and wheat and approximately 0.3 for soybean ) . In three-fifths of the 122 crop-state combinations assessed here, the NARO-APCC forecasts showed smaller forecast errors than those of the simple forecasts derived solely based on the reported yields. The findings of this study emphasize the novelty of long-range crop forecasting, such as the NARO-APCC forecasts that provide yield forecast information available even just after planting. Together, the NARO-APCC forecasts and existing regional crop forecasts contribute to making objective yield forecast information more seamlessly available throughout the season from planting to harvesting than what is currently available.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170604","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00018
Taku Yano, D. Yasutake, Yoshinobu Kiyosue
Under assuming that high‑yield canopy structure would be simply explained by a given index, orchard productivity of greenhouse‑grown early‑flowering satsuma mandarins “Miyagawa wase” was assessed using conventional modified‑open‑center‑training and trellis‑training methods. This was done by using universal indices that assist with determining yield in relation to canopy structure. Leaf area index was the optimum index for determining fruit yield. Empirical extinction coefficients showed negative linear trends with yield. Either plant area index, estimated by using a plant canopy analyzer, and crown cover showed poor correlation with fruit yield. To effectively predict yield from leaf area index, a direct measurement is recommended rather than an indirect optical method. Trellis‑trained trees were superior to modified‑open‑center‑trained trees. This is because trellis‑trained trees had higher fruit productivity up untill 10 yeas old, and because 15‑year‑olds had better canopy light distrubution patterns when compared with modified open‑center‑trained trees. Based on the costs associated with planting seedlings and the labor‑efficiency due to width of free alley, trellis‑training 2.2 m × 1.0 m plots was optimum for planting. In this study, even when accounting for the measurement error of woody elements, empirical extinction coefficients was a good index to base yield productivity. This is because this index directly represents vertical canopy light distribution. Additionally, the clumping index, calculated by using direct measurement and indirect optical method, was suggested to relate to canopy light distribution, however, further study must be essential.
在假设高产树冠结构可以简单地用一个给定的指数来解释的前提下，采用传统的改良开放式中心训练法和棚架训练法对温室栽培早花宫川蜜橘果园生产力进行了评估。这是通过使用有助于确定与冠层结构有关的产量的通用指数来完成的。叶面积指数是测定果实产量的最佳指标。经验消光系数与产量呈负线性关系。用植物冠层分析仪估算的植物面积指数和冠层盖度与果实产量均表现出较差的相关性。为了有效地预测叶面积指数的产量，建议直接测量而不是间接的光学方法。棚架训练的树木优于改良开放中心训练的树木。这是因为棚架训练的树木在10岁之前的果实产量更高，而且与改良的开放式中心训练的树木相比，15岁的树木有更好的冠层光分布模式。综合考虑种苗成本和自由通道宽度所带来的劳动效率，选择2.2 m × 1.0 m的棚架种植面积为最优。在本研究中，即使考虑到木质元素的测量误差，经验消光系数也能很好地反映基本产量。这是因为该指数直接代表了冠层的垂直光分布。此外，通过直接测量和间接光学方法计算得出的丛集指数与冠层光分布有关，但仍需进一步研究。
{"title":"Characterization of canopy structure for high-yield performance of greenhouse-grown satsuma mandarins using direct measurements and indirect estimations","authors":"Taku Yano, D. Yasutake, Yoshinobu Kiyosue","doi":"10.2480/agrmet.d-21-00018","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00018","url":null,"abstract":"Under assuming that high‑yield canopy structure would be simply explained by a given index, orchard productivity of greenhouse‑grown early‑flowering satsuma mandarins “Miyagawa wase” was assessed using conventional modified‑open‑center‑training and trellis‑training methods. This was done by using universal indices that assist with determining yield in relation to canopy structure. Leaf area index was the optimum index for determining fruit yield. Empirical extinction coefficients showed negative linear trends with yield. Either plant area index, estimated by using a plant canopy analyzer, and crown cover showed poor correlation with fruit yield. To effectively predict yield from leaf area index, a direct measurement is recommended rather than an indirect optical method. Trellis‑trained trees were superior to modified‑open‑center‑trained trees. This is because trellis‑trained trees had higher fruit productivity up untill 10 yeas old, and because 15‑year‑olds had better canopy light distrubution patterns when compared with modified open‑center‑trained trees. Based on the costs associated with planting seedlings and the labor‑efficiency due to width of free alley, trellis‑training 2.2 m × 1.0 m plots was optimum for planting. In this study, even when accounting for the measurement error of woody elements, empirical extinction coefficients was a good index to base yield productivity. This is because this index directly represents vertical canopy light distribution. Additionally, the clumping index, calculated by using direct measurement and indirect optical method, was suggested to relate to canopy light distribution, however, further study must be essential.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170443","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00030
Ting-Wei CHANG, Y. Kosugi, T. Kume, Ayumi Katayama, M. Okumura, Ken-Hui CHANG
It is challenging to estimate isoprene emissions from plants and determine the basal isoprene emission rate ( i.e., isoprene emission capacity under a specific light and leaf temperature ) of plant species. Previous studies have investigated the effect of physiological factors on isoprene emission capacity; however, the effect of leaf morphology on isoprene emission capacity has seldom been mentioned. This study aims to clarify the relationship between the basal isoprene emission rate and leaf mass per area ( LMA ) of a woody bamboo ( Phyllostachys pubescens ) . Since there was no observation of isoprene emission from low-LMA leaves of P. pubescens , we conducted measurements on culms exhibiting lower LMA ( 27.5 - 47.9 g m - 2 ) . By observing leaf-scale isoprene emission flux under a specific incident light ( 1000 μ mol m - 2 s - 1 ) and temperature ( 30 ° C ) to represent basal isoprene emission fluxes, we found a series of varied area-based isoprene emission rate among leaves ( 1.4 - 32.2 nmol m - 2 s - 1 ) and a strong correlation between area-based isoprene emission rate and LMA without any distinction between culms. A further comparison with other studies demonstrated that even for the culms that exhibited larger LMA and isoprene emission flux, a generally consistent pattern in the relation of area-isoprene emission flux and LMA could be found across these sites. This result suggests the importance of detecting LMA in the determination of the basal isoprene emission rate, which can improve the current emission estimation method.
估算植物的异戊二烯排放量并确定植物物种的基本异戊二烯排放量(即特定光和叶温下的异戊二烯排放能力)具有挑战性。以往的研究主要探讨了生理因素对异戊二烯排放能力的影响;然而，叶片形态对异戊二烯释放能力的影响很少被提及。本研究旨在阐明毛竹(Phyllostachys pubescens)的基础异戊二烯释放率与叶面积质量(LMA)的关系。由于没有观察到低LMA叶片的异戊二烯排放，我们对LMA较低(27.5 - 47.9 g m - 2)的茎秆进行了测量。在特定入射光(1000 μ mol m - 2 s - 1)和温度(30°C)条件下，通过观察异戊二烯在叶片尺度上的发射通量，我们发现了不同叶片间(1.4 ~ 32.2 nmol m - 2 s - 1)的不同面积异戊二烯发射率，且面积异戊二烯发射率与LMA之间存在较强的相关性，而不存在茎间差异。与其他研究的进一步比较表明，即使对于具有较大LMA和异戊二烯排放通量的culms，也可以在这些站点上发现面积-异戊二烯排放通量与LMA的关系大致一致。这一结果说明了LMA检测在测定基础异戊二烯排放率中的重要性，可以改进现有的排放率估算方法。
{"title":"Dependance of isoprene emission flux on leaf mass per area of Phyllostachys pubescens (moso bamboo)","authors":"Ting-Wei CHANG, Y. Kosugi, T. Kume, Ayumi Katayama, M. Okumura, Ken-Hui CHANG","doi":"10.2480/agrmet.d-21-00030","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00030","url":null,"abstract":"It is challenging to estimate isoprene emissions from plants and determine the basal isoprene emission rate ( i.e., isoprene emission capacity under a specific light and leaf temperature ) of plant species. Previous studies have investigated the effect of physiological factors on isoprene emission capacity; however, the effect of leaf morphology on isoprene emission capacity has seldom been mentioned. This study aims to clarify the relationship between the basal isoprene emission rate and leaf mass per area ( LMA ) of a woody bamboo ( Phyllostachys pubescens ) . Since there was no observation of isoprene emission from low-LMA leaves of P. pubescens , we conducted measurements on culms exhibiting lower LMA ( 27.5 - 47.9 g m - 2 ) . By observing leaf-scale isoprene emission flux under a specific incident light ( 1000 μ mol m - 2 s - 1 ) and temperature ( 30 ° C ) to represent basal isoprene emission fluxes, we found a series of varied area-based isoprene emission rate among leaves ( 1.4 - 32.2 nmol m - 2 s - 1 ) and a strong correlation between area-based isoprene emission rate and LMA without any distinction between culms. A further comparison with other studies demonstrated that even for the culms that exhibited larger LMA and isoprene emission flux, a generally consistent pattern in the relation of area-isoprene emission flux and LMA could be found across these sites. This result suggests the importance of detecting LMA in the determination of the basal isoprene emission rate, which can improve the current emission estimation method.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170513","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00032
Ryotaro Kitajima, O. Matsuda, T. Kumamaru, A. Kume
Rice ( Oryza sativa L. ) quality and yield are degraded by high temperature, especially at the ripening stage after the heading of panicles. The effect is lethal when the panicle temperature ( T p ) is excessively high; therefore, maintaining a low T p is important to avoid deleterious impacts on the grains. Microclimatic factors and plant physiological elements determine the T p . One determining factor is the color ( or reflectance ) of spikelets that constitute the panicle because it determines the absorption of shortwave radiation energy. An additional factor is the panicle position because it influences heat exchange by the wind and input energy from downward shortwave radiation. In this study, inter-strain differences in spikelet color and panicle height at heading were assessed. The T p of strains differing in panicle color and panicle height were measured with thermocouples. In addition, to estimate the effect of each trait, we adopted a micrometeorological model. Panicle color was quantified using a hyperspectral sensor. Combining the spectral reflectance and spectral radiation, we assessed the effect of panicle color on T p . The differences in panicle color and panicle position significantly affected T p . The strain with a dark panicle had a maximum measured T p about 1.8 ° C higher than that of the strain with a light-colored panicle. The T p of a strain with panicles at higher positions was up to 2.0 ° C higher than that of a strain with panicles at lower positions. These relationships were consistent with the model estimates. When shortwave radiation was strong, the difference in T p between strains showed a positive correlation, suggesting that the temperature difference was associated with shortwave radiation. Therefore, we concluded that rice strains with a brighter panicle color and low panicle position are less prone to deleterious impacts of high temperature because net radiation is reduced.
{"title":"Dark panicle color and high panicle position increase spikelet temperature of rice (Oryza sativa L.)","authors":"Ryotaro Kitajima, O. Matsuda, T. Kumamaru, A. Kume","doi":"10.2480/agrmet.d-21-00032","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00032","url":null,"abstract":"Rice ( Oryza sativa L. ) quality and yield are degraded by high temperature, especially at the ripening stage after the heading of panicles. The effect is lethal when the panicle temperature ( T p ) is excessively high; therefore, maintaining a low T p is important to avoid deleterious impacts on the grains. Microclimatic factors and plant physiological elements determine the T p . One determining factor is the color ( or reflectance ) of spikelets that constitute the panicle because it determines the absorption of shortwave radiation energy. An additional factor is the panicle position because it influences heat exchange by the wind and input energy from downward shortwave radiation. In this study, inter-strain differences in spikelet color and panicle height at heading were assessed. The T p of strains differing in panicle color and panicle height were measured with thermocouples. In addition, to estimate the effect of each trait, we adopted a micrometeorological model. Panicle color was quantified using a hyperspectral sensor. Combining the spectral reflectance and spectral radiation, we assessed the effect of panicle color on T p . The differences in panicle color and panicle position significantly affected T p . The strain with a dark panicle had a maximum measured T p about 1.8 ° C higher than that of the strain with a light-colored panicle. The T p of a strain with panicles at higher positions was up to 2.0 ° C higher than that of a strain with panicles at lower positions. These relationships were consistent with the model estimates. When shortwave radiation was strong, the difference in T p between strains showed a positive correlation, suggesting that the temperature difference was associated with shortwave radiation. Therefore, we concluded that rice strains with a brighter panicle color and low panicle position are less prone to deleterious impacts of high temperature because net radiation is reduced.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170524","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00037
Akihiko Ito, S. Inoue, M. Inatomi
Evaluating regional budgets of methane ( CH 4 ) , a potent greenhouse gas and short‑lived climate forcer, is an important task for future climate management. This study estimated historical CH 4 emissions from paddy fields in East Asia by using a process‑based terrestrial biogeochemical model driven by climate and land‑use data. To capture the range of estimation uncertainty, this study used two CH 4 emission schemes, four paddy field maps, and two seasonal inundation methods for a total of 16 simulations. The mean CH 4 emission rate during 2000 ‑ 2015 was estimated to be 5.7 Tg CH 4 yr ‑1 , which is similar to statistical inventories and other estimates. However, the large standard deviation ( ± 3.2 Tg CH 4 yr ‑1 ) among the simulations implies that serious estimation uncertainties remain. Three factors ‑ CH 4 emission scheme, paddy field map, and inundation seasonality ‑ were responsible for the disparity of the estimates. Because of the lack of historical management data, the model simulation did not show a decreasing trend in the agricultural CH 4 emissions. A sensitivity analysis for temperature indicated that a 1 ‑ 2 ° C temperature rise ( typical warming in mitigation‑oriented scenarios ) would substantially enhance CH 4 emissions. However, a sensitivity analysis for water management indicated that a lower water‑table depth would largely mitigate the emission increase. Additional studies to improve agricultural datasets and models for better paddy field management are still needed.
{"title":"Model-based evaluation of methane emissions from paddy fields in East Asia","authors":"Akihiko Ito, S. Inoue, M. Inatomi","doi":"10.2480/agrmet.d-21-00037","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00037","url":null,"abstract":"Evaluating regional budgets of methane ( CH 4 ) , a potent greenhouse gas and short‑lived climate forcer, is an important task for future climate management. This study estimated historical CH 4 emissions from paddy fields in East Asia by using a process‑based terrestrial biogeochemical model driven by climate and land‑use data. To capture the range of estimation uncertainty, this study used two CH 4 emission schemes, four paddy field maps, and two seasonal inundation methods for a total of 16 simulations. The mean CH 4 emission rate during 2000 ‑ 2015 was estimated to be 5.7 Tg CH 4 yr ‑1 , which is similar to statistical inventories and other estimates. However, the large standard deviation ( ± 3.2 Tg CH 4 yr ‑1 ) among the simulations implies that serious estimation uncertainties remain. Three factors ‑ CH 4 emission scheme, paddy field map, and inundation seasonality ‑ were responsible for the disparity of the estimates. Because of the lack of historical management data, the model simulation did not show a decreasing trend in the agricultural CH 4 emissions. A sensitivity analysis for temperature indicated that a 1 ‑ 2 ° C temperature rise ( typical warming in mitigation‑oriented scenarios ) would substantially enhance CH 4 emissions. However, a sensitivity analysis for water management indicated that a lower water‑table depth would largely mitigate the emission increase. Additional studies to improve agricultural datasets and models for better paddy field management are still needed.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170539","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 : 2022-01-01DOI: 10.2480/agrmet.d-21-00054
Robert Kennedy SMITH, José A. GUIJARRO, Der-Chen CHANG, Yiming CHEN
The northern U.S. Gulf Coast is among the wettest regions in the contiguous United States, with a transition zone from humid to semi-arid climates occurring between the western Gulf Coast and the 100 th meridian. As anthropogenic warming induces more frequent extreme wetting events of greater magnitude, a larger proportion of rainfall runs off unsaturated soils rather than being absorbed and replenishing vegetative water supply. This study introduced novel methodology reliant on reconstructed hourly precipitation intensity data from locations with comprehensive records from the past four decades, incorporating these records into a recursive algorithm measuring daily soil moisture levels. To account for runoff, curtailment multipliers for three different soil classes at each site were applied to 24-hour precipitation totals. Soil moisture balance was then obtained from daily evapotranspiration and infiltrated precipitation, and trends from the autoregressive time series modeling were compared. When runoff quantified by the methodology was considered, average annual soil moisture scarcity trends accelerated for most sample soils, including 13 of the 15 highly-infiltrative soils showing a change relative to the unrestricted infiltration in the reference case. The findings, however, were generally not statistically significant. These results are suggestive, but not conclusive, of a growing role from intense precipitation in drought development for the selected region. The seasonality of evolving rainfall rates in the case study area may explain the limited impact, as intensity rates are growing most quickly during the wintertime, a period when episodes infrequently exceed maximum soil infiltration capacity. The methods introduced here, achieving superior accuracy at precise locations relative to gridded products, are reproducible for global locations with adequate data coverage.
{"title":"Methodology to quantify the role of intense precipitation runoff in soil moisture scarcity: a case study in the U.S. South from 1980-2020","authors":"Robert Kennedy SMITH, José A. GUIJARRO, Der-Chen CHANG, Yiming CHEN","doi":"10.2480/agrmet.d-21-00054","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00054","url":null,"abstract":"The northern U.S. Gulf Coast is among the wettest regions in the contiguous United States, with a transition zone from humid to semi-arid climates occurring between the western Gulf Coast and the 100 th meridian. As anthropogenic warming induces more frequent extreme wetting events of greater magnitude, a larger proportion of rainfall runs off unsaturated soils rather than being absorbed and replenishing vegetative water supply. This study introduced novel methodology reliant on reconstructed hourly precipitation intensity data from locations with comprehensive records from the past four decades, incorporating these records into a recursive algorithm measuring daily soil moisture levels. To account for runoff, curtailment multipliers for three different soil classes at each site were applied to 24-hour precipitation totals. Soil moisture balance was then obtained from daily evapotranspiration and infiltrated precipitation, and trends from the autoregressive time series modeling were compared. When runoff quantified by the methodology was considered, average annual soil moisture scarcity trends accelerated for most sample soils, including 13 of the 15 highly-infiltrative soils showing a change relative to the unrestricted infiltration in the reference case. The findings, however, were generally not statistically significant. These results are suggestive, but not conclusive, of a growing role from intense precipitation in drought development for the selected region. The seasonality of evolving rainfall rates in the case study area may explain the limited impact, as intensity rates are growing most quickly during the wintertime, a period when episodes infrequently exceed maximum soil infiltration capacity. The methods introduced here, achieving superior accuracy at precise locations relative to gridded products, are reproducible for global locations with adequate data coverage.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":"6 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170614","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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