Pub Date : 2021-01-01DOI: 10.2480/AGRMET.D-20-00019
N. Dahal, Dong-hong Xiong, Nilhari Neupane, Bao-jun Zhang, Bin-tao Liu, Yong Yuan, Yi-ping Fang, S. Koirala, M. Rokaya
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 climatic factors ( temperature and precipitation ) . We also investigated the trends in the use of improved seeds, irrigation access, and fertilizer use in our study area. Results showed that there was an increase in yield of maize, rice, and wheat over 30‑year period. Maize yield slightly increased with increasing average temperature. Rice yields significantly decreased with increasing temperature and precipitation, whereas wheat yield increased with increasing the diurnal temperature range. The present study suggests that future yields of maize, rice, and wheat will be affected by the increasing temperature than precipitation in the Koshi River Basin, Nepal.
{"title":"Factors affecting maize, rice and wheat yields in the Koshi River Basin, Nepal","authors":"N. Dahal, Dong-hong Xiong, Nilhari Neupane, Bao-jun Zhang, Bin-tao Liu, Yong Yuan, Yi-ping Fang, S. Koirala, M. Rokaya","doi":"10.2480/AGRMET.D-20-00019","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00019","url":null,"abstract":"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 climatic factors ( temperature and precipitation ) . We also investigated the trends in the use of improved seeds, irrigation access, and fertilizer use in our study area. Results showed that there was an increase in yield of maize, rice, and wheat over 30‑year period. Maize yield slightly increased with increasing average temperature. Rice yields significantly decreased with increasing temperature and precipitation, whereas wheat yield increased with increasing the diurnal temperature range. The present study suggests that future yields of maize, rice, and wheat will be affected by the increasing temperature than precipitation in the Koshi River Basin, Nepal.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170197","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 : 2021-01-01DOI: 10.2480/AGRMET.D-20-00042
T. Hidayat, Y. Koesmaryono, I. Impron, M. Ghulamahdi
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. The second factor was the reflective mulch that included land without mulch, land with inorganic reflective mulch, and land with organic reflective mulch. The use of reflective mulch in the soybean - oil palm intercropping system was able to increase the reflection intensity of surface solar radiation, as well as increase the soybean solar radiation interception. The use of inorganic and organic reflective mulch significantly increased the leaf area, specific leaf weight, and soybean stomatal density. Organic reflective mulch led to significant reductions in the amount of chlorophyll A and B content. The photosynthetic rate of soybean in lower leaves was increased significantly. Inorganic reflective mulch resulted in significant reductions in the rate of transpiration, intercellular CO 2 concentration, and conductance of soybean stomata in lower leaves. The use of reflective mulch contributed to improved soybean performance under oil palm stands. The use of organic reflective mulch for soybean grown under oil palm stands aged up to 5 years resulted in better growth rates due to the increased intensity of solar radiation reflected from the surface. However, the reflection effect could not meet the needs of soybean solar radiation on land under oil palm stands aged >5 years due to the very low transmission. Therefore, the use of organic reflective mulch is more effective and efficient in the soybean - oil palm intercropping system until the oil palm reaches the age of 5 years.
{"title":"The effectiveness of reflective mulch in the intercropping system between soybean and oil palm: effects on growth, chlorophyll content, and photosynthetic characteristics","authors":"T. Hidayat, Y. Koesmaryono, I. Impron, M. Ghulamahdi","doi":"10.2480/AGRMET.D-20-00042","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00042","url":null,"abstract":"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. The second factor was the reflective mulch that included land without mulch, land with inorganic reflective mulch, and land with organic reflective mulch. The use of reflective mulch in the soybean - oil palm intercropping system was able to increase the reflection intensity of surface solar radiation, as well as increase the soybean solar radiation interception. The use of inorganic and organic reflective mulch significantly increased the leaf area, specific leaf weight, and soybean stomatal density. Organic reflective mulch led to significant reductions in the amount of chlorophyll A and B content. The photosynthetic rate of soybean in lower leaves was increased significantly. Inorganic reflective mulch resulted in significant reductions in the rate of transpiration, intercellular CO 2 concentration, and conductance of soybean stomata in lower leaves. The use of reflective mulch contributed to improved soybean performance under oil palm stands. The use of organic reflective mulch for soybean grown under oil palm stands aged up to 5 years resulted in better growth rates due to the increased intensity of solar radiation reflected from the surface. However, the reflection effect could not meet the needs of soybean solar radiation on land under oil palm stands aged >5 years due to the very low transmission. Therefore, the use of organic reflective mulch is more effective and efficient in the soybean - oil palm intercropping system until the oil palm reaches the age of 5 years.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170294","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}
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 the south accounted for 82.98 % and 82.94 % of the totals, respectively. May to August of each year is the intensive period of lightning disasters in China, and the number of deaths, injuries and disasters caused by lightning during these four months accounted for 84.80 % , 79.45 % and 82.77 % of the total numbers per year, respectively. From 2009 to 2018, the annual injury and death rates per million people in China were 0.13 and 0.12, respectively. After population weighting, the high death rate of lightning disaster shows a certain trend of transferring from the concentrated area to the sparsely populated area, after area weighting, the casualty density was higher in small provinces and lower in large provinces . The analysis of the environments in which lightning disaster casualties occurred found that environments closely related to agriculture, such as farmland ( 35 % ) and paddy fields or ponds ( 4 % ) , accounted for nearly 40 % of the casualties; accordingly, rural farmers were the main victims, accounting for 80.96 % of the total casualties. Lightning protection and disaster reduction measures in rural agricultural areas should be the focus of future work.
{"title":"Lightning fatalities in China, 2009-2018","authors":"Yin Qiyuan, Hengyi Liu, Xiangpeng Fan, Yijun Zhang, Zhuang Yanxun, Fei Wang, Hui-ying Du, Huang Xingxing, Shaodong Chen, Chen Lyuwen","doi":"10.2480/AGRMET.D-20-00045","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00045","url":null,"abstract":"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 the south accounted for 82.98 % and 82.94 % of the totals, respectively. May to August of each year is the intensive period of lightning disasters in China, and the number of deaths, injuries and disasters caused by lightning during these four months accounted for 84.80 % , 79.45 % and 82.77 % of the total numbers per year, respectively. From 2009 to 2018, the annual injury and death rates per million people in China were 0.13 and 0.12, respectively. After population weighting, the high death rate of lightning disaster shows a certain trend of transferring from the concentrated area to the sparsely populated area, after area weighting, the casualty density was higher in small provinces and lower in large provinces . The analysis of the environments in which lightning disaster casualties occurred found that environments closely related to agriculture, such as farmland ( 35 % ) and paddy fields or ponds ( 4 % ) , accounted for nearly 40 % of the casualties; accordingly, rural farmers were the main victims, accounting for 80.96 % of the total casualties. Lightning protection and disaster reduction measures in rural agricultural areas should be the focus of future work.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170302","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 : 2021-01-01DOI: 10.2480/AGRMET.D-20-00018
Shih-Chieh Chang, T. Saitoh, H. Shibata, Satoshi N. Suzuki
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 from eddy covariance CO 2 flux sites in East Asia to clarify these ecosystem processes and attributes. Since the establishment of AsiaFlux in 1999, the number of flux tower sites has grown to 110 sites, spanning a large geographic extent in East Asia and covering diverse ecosystems embedded in large climatic gradients. Early publications relating to AsiaFlux described CO 2 fluxes from single sites, but over the last 20 years more ecosystem processes and attributes have been included in the study sites’ research programs. Among other advances, researchers have quantified the plant functional traits related to photosynthesis or ecosystem-scale gross primary production and thus demonstrated that CO 2 fluxes are controlled by plant traits; this quantification provides a basis for building ecosystem models. Additional means of understanding the carbon fluxes and pools of these ecosystems have been provided by biometric measurements beneath eddy covariance flux towers, partly on the basis of traditional forestry practices and the measurements of component carbon fluxes, such as respiratory fluxes and litter decomposition rates. Through meta-analyses, we demonstrate good correlations between these fluxes and mention the characteristics of carbon cycle processes in Asian forest ecosystems. By investigating nitrogen biogeochemical cycles at the flux sites, studies have shown that carbon fluxes are also controlled by nitrogen availability. The future success and progress of AsiaFlux could be promoted by further collaborations between this research community and other networks, such as long-term ecological research ( LTER ) networks, and the development of open databases.
{"title":"Recent advances in the understanding of ecosystem processes at eddy covariance CO2 flux sites in East Asian forest ecosystems: a review","authors":"Shih-Chieh Chang, T. Saitoh, H. Shibata, Satoshi N. Suzuki","doi":"10.2480/AGRMET.D-20-00018","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00018","url":null,"abstract":"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 from eddy covariance CO 2 flux sites in East Asia to clarify these ecosystem processes and attributes. Since the establishment of AsiaFlux in 1999, the number of flux tower sites has grown to 110 sites, spanning a large geographic extent in East Asia and covering diverse ecosystems embedded in large climatic gradients. Early publications relating to AsiaFlux described CO 2 fluxes from single sites, but over the last 20 years more ecosystem processes and attributes have been included in the study sites’ research programs. Among other advances, researchers have quantified the plant functional traits related to photosynthesis or ecosystem-scale gross primary production and thus demonstrated that CO 2 fluxes are controlled by plant traits; this quantification provides a basis for building ecosystem models. Additional means of understanding the carbon fluxes and pools of these ecosystems have been provided by biometric measurements beneath eddy covariance flux towers, partly on the basis of traditional forestry practices and the measurements of component carbon fluxes, such as respiratory fluxes and litter decomposition rates. Through meta-analyses, we demonstrate good correlations between these fluxes and mention the characteristics of carbon cycle processes in Asian forest ecosystems. By investigating nitrogen biogeochemical cycles at the flux sites, studies have shown that carbon fluxes are also controlled by nitrogen availability. The future success and progress of AsiaFlux could be promoted by further collaborations between this research community and other networks, such as long-term ecological research ( LTER ) networks, and the development of open databases.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170131","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 : 2021-01-01DOI: 10.2480/AGRMET.D-20-00101
Guirui Yu, T. Hirano
{"title":"Review and future perspective of AsiaFlux","authors":"Guirui Yu, T. Hirano","doi":"10.2480/AGRMET.D-20-00101","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00101","url":null,"abstract":"","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170355","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 : 2021-01-01DOI: 10.2480/AGRMET.D-20-00029
T. Tokida
Manually operated closed-chamber methods have been used extensively to measure CH 4 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 method suitable for high-throughput measurements. The design of the modified system is based on a conventional method, but uses a portable spectroscopic gas analyzer and a newly developed dehumidification system. Results of a series of test operations showed that the use of a portable gas analyzer substantially reduced the time needed for each chamber deployment to as little as 4–5 min. A simple dehumidification system employing a selective water vapor-permeable tube was introduced to effectively dehumidify the sample gas so that the risk of water condensation was removed without attenuating the CH 4 concentration signal. The chamber must be equipped with a fan to ensure that the chamber air is well mixed and to attain representative CH 4 concentration values. The new method is suitable for high-throughput CH 4 emission measurements and can also be used for studying bubbling CH 4 emissions.
{"title":"Increasing measurement throughput of methane emission from rice paddies with a modified closed-chamber method","authors":"T. Tokida","doi":"10.2480/AGRMET.D-20-00029","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00029","url":null,"abstract":"Manually operated closed-chamber methods have been used extensively to measure CH 4 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 method suitable for high-throughput measurements. The design of the modified system is based on a conventional method, but uses a portable spectroscopic gas analyzer and a newly developed dehumidification system. Results of a series of test operations showed that the use of a portable gas analyzer substantially reduced the time needed for each chamber deployment to as little as 4–5 min. A simple dehumidification system employing a selective water vapor-permeable tube was introduced to effectively dehumidify the sample gas so that the risk of water condensation was removed without attenuating the CH 4 concentration signal. The chamber must be equipped with a fan to ensure that the chamber air is well mixed and to attain representative CH 4 concentration values. The new method is suitable for high-throughput CH 4 emission measurements and can also be used for studying bubbling CH 4 emissions.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170208","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 : 2021-01-01DOI: 10.2480/agrmet.d-21-00014
R. Matsuda
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 and an extended photoperiod of 24 h d were compared at two photosynthetic photon flux density (PPFD) levels of 200 and 400 μmol m s. Leaf biomass was greater in the 24 h d photoperiod treatments and 400 μmol m s PPFD treatments. The leaf HA content per biomass was smaller at 24 h d than at 16 h d, indicating that CL before gene transfer had a negative impact on leaf HA accumulation per biomass after gene transfer. There was no significant difference in leaf HA content per biomass between 200 and 400 μmol m s PPFD. As a result, the leaf HA content per plant was significantly greater in the high PPFD treatments but not significantly different between photoperiod treatments. The results indicate that a simple approach of applying CL before gene transfer increases biomass but not the HA yield and is thus not necessarily cost‐effective in the plant‐based recombinant protein production system.
在瞬时基因表达系统中，研究了基因转移前连续光照(CL)对烟叶生物量、单株血凝素(HA)含量和基因转移后单株HA含量的影响。在200 μmol m s和400 μmol m s的光合光子通量(PPFD)水平下，对照光周期为16 h d和延长光周期为24 h d，叶片生物量在24 h d光周期处理和400 μmol m s PPFD处理下较大。24 h时叶片每生物量HA含量低于16 h时，说明基因转移前的CL对基因转移后叶片每生物量HA积累有负向影响。200 μmol m s PPFD和400 μmol m s PPFD对每生物量叶片HA含量无显著影响。结果表明，高PPFD处理单株叶片HA含量显著高于高PPFD处理，但不同光周期处理间差异不显著。结果表明，在基因转移之前施用CL的简单方法增加了生物量，但不能提高HA产量，因此在基于植物的重组蛋白生产系统中不一定具有成本效益。
{"title":"A 24-h photoperiod before gene transfer promotes biomass production but not the yield of influenza hemagglutinin transiently expressed in Nicotiana benthamiana","authors":"R. Matsuda","doi":"10.2480/agrmet.d-21-00014","DOIUrl":"https://doi.org/10.2480/agrmet.d-21-00014","url":null,"abstract":"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 and an extended photoperiod of 24 h d were compared at two photosynthetic photon flux density (PPFD) levels of 200 and 400 μmol m s. Leaf biomass was greater in the 24 h d photoperiod treatments and 400 μmol m s PPFD treatments. The leaf HA content per biomass was smaller at 24 h d than at 16 h d, indicating that CL before gene transfer had a negative impact on leaf HA accumulation per biomass after gene transfer. There was no significant difference in leaf HA content per biomass between 200 and 400 μmol m s PPFD. As a result, the leaf HA content per plant was significantly greater in the high PPFD treatments but not significantly different between photoperiod treatments. The results indicate that a simple approach of applying CL before gene transfer increases biomass but not the HA yield and is thus not necessarily cost‐effective in the plant‐based recombinant protein production system.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170427","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 : 2021-01-01DOI: 10.2480/agrmet.d-20-00024
A. Ito, K. Ichii
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, AsiaFlux. Process-based biogeochemical models have been developed to simulate the carbon cycle, and their accuracy has been verified by comparing with carbon dioxide flux data. The development and use of data-driven ( statistical and machine learning ) models has further enhanced the utilization of field survey and satellite remote sensing data. Model intercomparison studies were also conducted by using the AsiaFlux dataset for uncertainty analyses and benchmarking. Other types of models, such as cropland models and trace gas emission models, are also briefly reviewed here. Finally, we discuss the present status and remaining issues in data - model integration, regional synthesis, and future projection with the models.
{"title":"Terrestrial ecosystem model studies and their contributions to AsiaFlux","authors":"A. Ito, K. Ichii","doi":"10.2480/agrmet.d-20-00024","DOIUrl":"https://doi.org/10.2480/agrmet.d-20-00024","url":null,"abstract":"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, AsiaFlux. Process-based biogeochemical models have been developed to simulate the carbon cycle, and their accuracy has been verified by comparing with carbon dioxide flux data. The development and use of data-driven ( statistical and machine learning ) models has further enhanced the utilization of field survey and satellite remote sensing data. Model intercomparison studies were also conducted by using the AsiaFlux dataset for uncertainty analyses and benchmarking. Other types of models, such as cropland models and trace gas emission models, are also briefly reviewed here. Finally, we discuss the present status and remaining issues in data - model integration, regional synthesis, and future projection with the models.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170201","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 : 2021-01-01DOI: 10.2480/AGRMET.D-20-00043
G. Dumbuya, H. Alemayehu, M. Hasan, Maya Matsunami, H. Shimono
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 ( T s ) on growth and yield in sweet potato from 2-year field trials in northern Japan. T s was controlled by three steps using plastic mulch at different colors ( green, black and white ) with different T s ranged in 21~24 ° C especially at early growth before the surface of the mulch covered by plant canopy. Higher T s significantly increased vine elongation, branching, and leaf appearance, and the magnitude of increased by higher T s decreased with proceeding growth stages. Increasing T s significantly increased leaf chlorophyll content and stomatal conductance. Across treatments and years, aboveground biomass was linearly and positively correlated with T s , and 58 g m -2 increased in aboveground biomass was observed per 1 ° C increase in T s . However, final storage root fresh yield was not significantly affected by high T s over years. Increased individual storage root weight at high T s was offset by decreased storage root number. The present quantitative study tested in northern Japan showed that, the enhanced aboveground growth in sweet potato at higher T s especially during early growth did not contribute to increase of storage root yields in cool climates.
在寒冷气候下，低温对甘薯的生长和产量至关重要。． 尽管它有负面影响，但很少有研究对其影响进行量化。通过在日本北部进行的2年田间试验，评价了土壤温度对甘薯生长和产量的影响。在21~24℃范围内，采用不同颜色(绿、黑、白)的地膜分三步控制温度，特别是在覆盖冠层之前的生长早期。高温度显著提高了葡萄的伸长、分枝和叶片外观，且随着生长阶段的推进，高温度增加的幅度逐渐减小。增加T显著提高叶片叶绿素含量和气孔导度。在不同处理和年份，地上生物量与T s呈线性正相关，T s每增加1°C，地上生物量增加58 g m -2。但高温度对最终贮藏根鲜产量的影响不显著。在高温度下，单株储存根重的增加被储存根数的减少所抵消。目前在日本北部进行的定量研究表明，在寒冷气候条件下，高温度条件下甘薯地上部生长的增强，特别是生长早期的增强，对贮藏根产量的增加没有贡献。
{"title":"Effect of soil temperature on growth and yield of sweet potato (Ipomoea batatas L.) under cool climate","authors":"G. Dumbuya, H. Alemayehu, M. Hasan, Maya Matsunami, H. Shimono","doi":"10.2480/AGRMET.D-20-00043","DOIUrl":"https://doi.org/10.2480/AGRMET.D-20-00043","url":null,"abstract":"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 ( T s ) on growth and yield in sweet potato from 2-year field trials in northern Japan. T s was controlled by three steps using plastic mulch at different colors ( green, black and white ) with different T s ranged in 21~24 ° C especially at early growth before the surface of the mulch covered by plant canopy. Higher T s significantly increased vine elongation, branching, and leaf appearance, and the magnitude of increased by higher T s decreased with proceeding growth stages. Increasing T s significantly increased leaf chlorophyll content and stomatal conductance. Across treatments and years, aboveground biomass was linearly and positively correlated with T s , and 58 g m -2 increased in aboveground biomass was observed per 1 ° C increase in T s . However, final storage root fresh yield was not significantly affected by high T s over years. Increased individual storage root weight at high T s was offset by decreased storage root number. The present quantitative study tested in northern Japan showed that, the enhanced aboveground growth in sweet potato at higher T s especially during early growth did not contribute to increase of storage root yields in cool climates.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170298","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 : 2021-01-01DOI: 10.2480/agrmet.d-20-00025
A. Tani, Tomoki Mochizuki
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 reviewed in this paper. Representative VOCs emitted from terrestrial ecosystems are low-molecular-weight oxygenated VOCs including methanol, acetone, formic and acetic acids, and terpenoids, including isoprene and monoterpenes. Terpenoid emissions have been intensively investigated from the leaf to the canopy level using advanced analytical systems, including proton-transfer-reaction mass spectrometry. Environmental factors, including temperature, light intensity, carbon dioxide and ozone concentrations, and water stress have been reported to affect terpenoid emissions from plants. The combined effects of these environments influence terpenoid emission additively or interactively, and are important in terms of VOC emission estimates against ongoing climate change. Isoprene is most abundantly released into the atmosphere among VOCs; the potential reasons why some plants release such large amounts of carbon as isoprene were summarized in this study. Among oxygenated VOCs, some compounds, including isoprene oxygenates methacrolein and methyl vinyl ketone, are bidirectionally exchanged, and both atmospheric chemical reactions and reactions under oxidative stress in leaves have been regarded as involved in bidirectional VOC exchanges. Bottom-up process-based models and top-down inverse models have been developed to estimate global and local terpenoid emissions. To validate the accuracy and precision of the models, the collection of additional in-situ ground truth data, such as long-term flux measurement data, at various sites is required. Otherwise, these models may still leave large uncertainties compared with CO2 flux models that can be validated with a large number of ground truth flux data.
{"title":"Review: Exchanges of volatile organic compounds between terrestrial ecosystems and the atmosphere","authors":"A. Tani, Tomoki Mochizuki","doi":"10.2480/agrmet.d-20-00025","DOIUrl":"https://doi.org/10.2480/agrmet.d-20-00025","url":null,"abstract":"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 reviewed in this paper. Representative VOCs emitted from terrestrial ecosystems are low-molecular-weight oxygenated VOCs including methanol, acetone, formic and acetic acids, and terpenoids, including isoprene and monoterpenes. Terpenoid emissions have been intensively investigated from the leaf to the canopy level using advanced analytical systems, including proton-transfer-reaction mass spectrometry. Environmental factors, including temperature, light intensity, carbon dioxide and ozone concentrations, and water stress have been reported to affect terpenoid emissions from plants. The combined effects of these environments influence terpenoid emission additively or interactively, and are important in terms of VOC emission estimates against ongoing climate change. Isoprene is most abundantly released into the atmosphere among VOCs; the potential reasons why some plants release such large amounts of carbon as isoprene were summarized in this study. Among oxygenated VOCs, some compounds, including isoprene oxygenates methacrolein and methyl vinyl ketone, are bidirectionally exchanged, and both atmospheric chemical reactions and reactions under oxidative stress in leaves have been regarded as involved in bidirectional VOC exchanges. Bottom-up process-based models and top-down inverse models have been developed to estimate global and local terpenoid emissions. To validate the accuracy and precision of the models, the collection of additional in-situ ground truth data, such as long-term flux measurement data, at various sites is required. Otherwise, these models may still leave large uncertainties compared with CO2 flux models that can be validated with a large number of ground truth flux data.","PeriodicalId":56074,"journal":{"name":"Journal of Agricultural Meteorology","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69170204","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：