Pub Date : 2025-01-13DOI: 10.1016/j.agrformet.2025.110392
Jon Detka , Mohammad Jafari , Marcella Gomez , Gregory S. Gilbert
This study presents the development and application of models to estimate leaf wetness duration and their integration with drone-based imagery to analyze plant disease patterns across a coastal gradient. By comparing machine learning algorithms with empirical models, we identified that both approaches effectively predict leaf wetness, particularly in a temperate maritime ecosystem. The models were applied to study two manzanita species (Arctostaphylos tomentosa and A. pumila), revealing a strong correlation between leaf wetness and disease prevalence. This work highlights the role of microclimate conditions in shaping plant health and disease distribution in coastal shrublands. We compared nine popular machine learning algorithms and four empirical threshold models to characterize leaf wetness patterns in a spatially diverse temperate maritime wildland ecosystem. We suggest that simple empirical leaf wetness models based on dew point depression or relative humidity thresholds perform as well as machine learning techniques and should not be overlooked. The relationship between leaf wetness duration and the spatial distribution of plant disease along a coastal-to-inland climate gradient offers valuable insights into disease dynamics.
本研究介绍了估算叶片湿润度持续时间的模型的开发和应用，以及这些模型与无人机图像的整合，以分析沿海梯度的植物病害模式。通过比较机器学习算法和经验模型，我们发现这两种方法都能有效预测叶片湿润度，尤其是在温带海洋生态系统中。这些模型被应用于研究两种芒草（Arctostaphylos tomentosa 和 A. pumila），发现叶片湿度与疾病流行之间存在很强的相关性。这项工作凸显了小气候条件在塑造沿海灌木林植物健康和病害分布中的作用。我们比较了九种流行的机器学习算法和四种经验阈值模型，以描述一个空间多样的温带海洋野生生态系统的叶片湿度模式。我们认为，基于露点降低或相对湿度阈值的简单经验叶片湿度模型与机器学习技术的表现一样好，不应被忽视。沿着沿海到内陆的气候梯度，叶片湿度持续时间与植物病害空间分布之间的关系为了解病害动态提供了宝贵的信息。
{"title":"Machine learning vs. empirical models: Estimating leaf wetness patterns in a wildland landscape for plant disease management","authors":"Jon Detka , Mohammad Jafari , Marcella Gomez , Gregory S. Gilbert","doi":"10.1016/j.agrformet.2025.110392","DOIUrl":"10.1016/j.agrformet.2025.110392","url":null,"abstract":"<div><div>This study presents the development and application of models to estimate leaf wetness duration and their integration with drone-based imagery to analyze plant disease patterns across a coastal gradient. By comparing machine learning algorithms with empirical models, we identified that both approaches effectively predict leaf wetness, particularly in a temperate maritime ecosystem. The models were applied to study two manzanita species (<em>Arctostaphylos tomentosa</em> and <em>A. pumila</em>), revealing a strong correlation between leaf wetness and disease prevalence. This work highlights the role of microclimate conditions in shaping plant health and disease distribution in coastal shrublands. We compared nine popular machine learning algorithms and four empirical threshold models to characterize leaf wetness patterns in a spatially diverse temperate maritime wildland ecosystem. We suggest that simple empirical leaf wetness models based on dew point depression or relative humidity thresholds perform as well as machine learning techniques and should not be overlooked. The relationship between leaf wetness duration and the spatial distribution of plant disease along a coastal-to-inland climate gradient offers valuable insights into disease dynamics.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110392"},"PeriodicalIF":5.6,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142974719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-12DOI: 10.1016/j.agrformet.2025.110391
Ching-Hung Shih , Ray G. Anderson , Todd. H. Skaggs , Jehn-Yih Juang , Yi-Ying Chen , Yi-Shin Jang , Rong-Yu Gu , Cho-Ying Huang , Min-Hui Lo
Partitioning evapotranspiration components is crucial for an in-depth understanding of energy, water, and carbon cycles in agricultural and forest ecosystems. In this study, the Flux Variance Similarity (FVS) method, lauded for its capability to segregate eddy covariance datasets' evapotranspiration, was applied in Taiwan's Chi-Lan montane cloud forest and the Lien-Hua-Chih forest. However, we discovered a biased early peak of transpiration using the FVS method in the Chi-Lan montane cloud forest that did not align with the diurnal cycle of transpiration obtained from the Community Land Model, observed sap flow velocity, and net radiation. This bias is attributed to the rapid increase in specific humidity, caused by additional water vapor sources from valley wind. This factor violates the FVS method's assumptions and leads to an early peak in CO2 fluxes describing the net primary production (NPP). Furthermore, the high relative humidity conditions from afternoon to evening contribute to a larger magnitude of leaf-level water use efficiency, primarily due to minimal gradients between intercellular and ambient water vapor concentrations. The early peak of net primary production and water use efficiency skew the diurnal course of estimated transpiration. Additionally, the substantial canopy evaporation in the morning and the uncertainty in water use efficiency during periods of high relative humidity contribute to the overall uncertainty in transpiration values. Consequently, the application of the FVS method in environments akin to the Chi-Lan montane cloud forest warrants caution due to the intrinsic uncertainty. Our research emphasizes the imperative to explore different evapotranspiration partitioning techniques, especially in topographies like mountainous regions where diurnal water vapor accumulation is swift and places that are consistently subjected to high relative humidity.
{"title":"Challenges and limitations of applying the flux variance similarity (FVS) method to partition evapotranspiration in a montane cloud forest","authors":"Ching-Hung Shih , Ray G. Anderson , Todd. H. Skaggs , Jehn-Yih Juang , Yi-Ying Chen , Yi-Shin Jang , Rong-Yu Gu , Cho-Ying Huang , Min-Hui Lo","doi":"10.1016/j.agrformet.2025.110391","DOIUrl":"10.1016/j.agrformet.2025.110391","url":null,"abstract":"<div><div>Partitioning evapotranspiration components is crucial for an in-depth understanding of energy, water, and carbon cycles in agricultural and forest ecosystems. In this study, the Flux Variance Similarity (FVS) method, lauded for its capability to segregate eddy covariance datasets' evapotranspiration, was applied in Taiwan's Chi-Lan montane cloud forest and the Lien-Hua-Chih forest. However, we discovered a biased early peak of transpiration using the FVS method in the Chi-Lan montane cloud forest that did not align with the diurnal cycle of transpiration obtained from the Community Land Model, observed sap flow velocity, and net radiation. This bias is attributed to the rapid increase in specific humidity, caused by additional water vapor sources from valley wind. This factor violates the FVS method's assumptions and leads to an early peak in CO<sub>2</sub> fluxes describing the net primary production (NPP). Furthermore, the high relative humidity conditions from afternoon to evening contribute to a larger magnitude of leaf-level water use efficiency, primarily due to minimal gradients between intercellular and ambient water vapor concentrations. The early peak of net primary production and water use efficiency skew the diurnal course of estimated transpiration. Additionally, the substantial canopy evaporation in the morning and the uncertainty in water use efficiency during periods of high relative humidity contribute to the overall uncertainty in transpiration values. Consequently, the application of the FVS method in environments akin to the Chi-Lan montane cloud forest warrants caution due to the intrinsic uncertainty. Our research emphasizes the imperative to explore different evapotranspiration partitioning techniques, especially in topographies like mountainous regions where diurnal water vapor accumulation is swift and places that are consistently subjected to high relative humidity.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110391"},"PeriodicalIF":5.6,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-11DOI: 10.1016/j.agrformet.2025.110387
Wenqiang Gao , Jianfeng Liu , Wenquan Bao , Fujun Duan , Xiao He , Dongli Gao , Xiangdong Lei
Impending climate change is anticipated to exacerbate the frequency and severity of extreme droughts, significantly affecting tree growth and distribution ranges. A critical endeavor in predicting how tree species will respond to more frequent and intense severe droughts is assessing the drought sensitivity and resilience of tree growth across a species' different range. However, the variation in tree growth resistance and resilience to extreme droughts across different distribution range edges have received little attention. In this study, we analyzed tree ring width data from 596 trees across 19 sites, encompassing the northernmost and southernmost distribution limits of Juniperus rigida in China. Our objectives were to delineate patterns of growth resistance, recovery and resilience to extreme droughts between northern and southern populations, and to assess their driving factors. Our findings revealed that the drought events significantly reduced the tree growth. Specifically, the tree growth has exhibited a decreasing trend in the northern distribution range limit, but an increasing trend at southern range limit since 1996, due to the more frequent and severe droughts in the northern region than in the southern. Furthermore, although the tree growth resistance and resilience were significantly higher in the northern limits than those in the southern, more frequent droughts will reduce their resistance and resilience. In addition, the growth resistance and resilience were also affected by factors such as tree age, pre-drought growth (e.g. mean growth rate and variability), and the interaction between drought characteristics and pre-drought growth. We conclude that J. rigida trees exhibit greater resistance and resilience to drought at their northern range limits compared to their southern counterparts. However, the increasing frequency and severity of droughts in the northern expose these trees to more persistent drought conditions, which could ultimately result in a decline in resilience and growth.
{"title":"Extreme droughts decrease the growth and resilience of Juniperus rigida in the northern edge but not in the southern","authors":"Wenqiang Gao , Jianfeng Liu , Wenquan Bao , Fujun Duan , Xiao He , Dongli Gao , Xiangdong Lei","doi":"10.1016/j.agrformet.2025.110387","DOIUrl":"10.1016/j.agrformet.2025.110387","url":null,"abstract":"<div><div>Impending climate change is anticipated to exacerbate the frequency and severity of extreme droughts, significantly affecting tree growth and distribution ranges. A critical endeavor in predicting how tree species will respond to more frequent and intense severe droughts is assessing the drought sensitivity and resilience of tree growth across a species' different range. However, the variation in tree growth resistance and resilience to extreme droughts across different distribution range edges have received little attention. In this study, we analyzed tree ring width data from 596 trees across 19 sites, encompassing the northernmost and southernmost distribution limits of <em>Juniperus rigida</em> in China. Our objectives were to delineate patterns of growth resistance, recovery and resilience to extreme droughts between northern and southern populations, and to assess their driving factors. Our findings revealed that the drought events significantly reduced the tree growth. Specifically, the tree growth has exhibited a decreasing trend in the northern distribution range limit, but an increasing trend at southern range limit since 1996, due to the more frequent and severe droughts in the northern region than in the southern. Furthermore, although the tree growth resistance and resilience were significantly higher in the northern limits than those in the southern, more frequent droughts will reduce their resistance and resilience. In addition, the growth resistance and resilience were also affected by factors such as tree age, pre-drought growth (e.g. mean growth rate and variability), and the interaction between drought characteristics and pre-drought growth. We conclude that <em>J. rigida</em> trees exhibit greater resistance and resilience to drought at their northern range limits compared to their southern counterparts. However, the increasing frequency and severity of droughts in the northern expose these trees to more persistent drought conditions, which could ultimately result in a decline in resilience and growth.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110387"},"PeriodicalIF":5.6,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-10DOI: 10.1016/j.agrformet.2025.110388
Jiwang Tang , Ben Niu , Gang Fu , Jinlong Peng , Zhigang Hu , Xianzhou Zhang
Drought has imposed severe effects on vegetation productivity, and such impacts will continue to increase under ongoing climate change. However, long-term changes in vegetation sensitivity to drought (Sdro) remain poorly understood. Here, with satellite-based vegetation indexes (kNDVI and LAI) and soil moisture dataset, we investigated the spatiotemporal patterns of Sdro across the global land during 1982–2020. We found that Sdro was higher in dry regions in comparison to humid regions, and grasslands showed the highest Sdro while forests showed the lowest one. Temporally, the overall Sdro increased first and then decreased over past four decades. More than 55 % of global vegetated areas experienced a conversion from an increased trend to a declined trend in Sdro, which concentrated in humid regions. The potential driving mechanisms of these converted Sdro trends were mostly related to climate changes and varied regionally, with VPD in northern Europe, temperature in middle Africa, and precipitation in western America and northern India. Our findings underscore a shifted trend in vulnerability of terrestrial ecosystems to drought especially in global humid regions.
{"title":"Shifted trend in drought sensitivity of vegetation productivity from 1982 to 2020","authors":"Jiwang Tang , Ben Niu , Gang Fu , Jinlong Peng , Zhigang Hu , Xianzhou Zhang","doi":"10.1016/j.agrformet.2025.110388","DOIUrl":"10.1016/j.agrformet.2025.110388","url":null,"abstract":"<div><div>Drought has imposed severe effects on vegetation productivity, and such impacts will continue to increase under ongoing climate change. However, long-term changes in vegetation sensitivity to drought (S<sub>dro</sub>) remain poorly understood. Here, with satellite-based vegetation indexes (kNDVI and LAI) and soil moisture dataset, we investigated the spatiotemporal patterns of S<sub>dro</sub> across the global land during 1982–2020. We found that S<sub>dro</sub> was higher in dry regions in comparison to humid regions, and grasslands showed the highest S<sub>dro</sub> while forests showed the lowest one. Temporally, the overall S<sub>dro</sub> increased first and then decreased over past four decades. More than 55 % of global vegetated areas experienced a conversion from an increased trend to a declined trend in S<sub>dro</sub>, which concentrated in humid regions. The potential driving mechanisms of these converted S<sub>dro</sub> trends were mostly related to climate changes and varied regionally, with VPD in northern Europe, temperature in middle Africa, and precipitation in western America and northern India. Our findings underscore a shifted trend in vulnerability of terrestrial ecosystems to drought especially in global humid regions.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110388"},"PeriodicalIF":5.6,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-10DOI: 10.1016/j.agrformet.2025.110384
Shenliang Zhao , Hua Chai , Yuan Liu , Xiaochun Wang , Chaolian Jiao , Cheng Liu , Li Xu , Jie Li , Nianpeng He
How and what soil fauna influence the soil organic matter (SOM) decomposition rate (Rs) and its temperature sensitivity (Q10) have been largely ignored, although this is a crucial matter, especially under the scenario of global change. In this study, a novel approach was adopted with a continuous changing-temperature incubation (daytime, from 7 °C to 22 °C; nighttime, from 22 °C to 7 °C) with rapid and continuous measurement, to examine the effect of soil macrofauna (specifically, earthworms) on Rs and Q10 with three densities (no addition, low density, and high density). According to the results, the earthworms accelerated Rs. Furthermore, Rs with earthworm addition had a symmetrical pattern during daytime and nighttime cycles, which is contrary to traditional soil incubation, with only soil microbe as asymmetrical. More importantly, earthworm addition increased Q10 markedly, ranging from 48% to 67%. Overall, the findings highlight the pivotal role of earthworms as soil macrofauna that regulating soil carbon release, and their effects should be integrated into process-based ecological models in future.
{"title":"Earthworms significantly enhance the temperature sensitivity of soil organic matter decomposition: Insights into future soil carbon budgeting","authors":"Shenliang Zhao , Hua Chai , Yuan Liu , Xiaochun Wang , Chaolian Jiao , Cheng Liu , Li Xu , Jie Li , Nianpeng He","doi":"10.1016/j.agrformet.2025.110384","DOIUrl":"10.1016/j.agrformet.2025.110384","url":null,"abstract":"<div><div>How and what soil fauna influence the soil organic matter (SOM) decomposition rate (<em>R</em>s) and its temperature sensitivity (<em>Q</em><sub>10</sub>) have been largely ignored, although this is a crucial matter, especially under the scenario of global change. In this study, a novel approach was adopted with a continuous changing-temperature incubation (daytime, from 7 °C to 22 °C; nighttime, from 22 °C to 7 °C) with rapid and continuous measurement, to examine the effect of soil macrofauna (specifically, earthworms) on <em>R</em>s and <em>Q</em><sub>10</sub> with three densities (no addition, low density, and high density). According to the results, the earthworms accelerated <em>R</em>s. Furthermore, <em>R</em>s with earthworm addition had a symmetrical pattern during daytime and nighttime cycles, which is contrary to traditional soil incubation, with only soil microbe as asymmetrical. More importantly, earthworm addition increased <em>Q</em><sub>10</sub> markedly<sub>,</sub> ranging from 48% to 67%. Overall, the findings highlight the pivotal role of earthworms as soil macrofauna that regulating soil carbon release, and their effects should be integrated into process-based ecological models in future.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110384"},"PeriodicalIF":5.6,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-07DOI: 10.1016/j.agrformet.2025.110385
Tianyu Zheng , Huixing Kang , Yuan Yu , Tong Guo , Xinran Ke , Owen K. Atkin , Yanhong Tang
Current estimates of diel respiratory carbon release depend on accurate predictions of the temperature sensitivity (Q10) of leaf respiration during the day and night. Such predictions typically rely on measurements of the Q10 of respiration in the light (RL) and dark (RD) made during the day, and assuming that the Q10 of nocturnal respiration (RN) equals that of RD. Using RD as a surrogate for RN, however, creates errors in estimates of diel respiration whenever the Q10 of RD and RN differ. Using measurements made on field-grown, high-altitude alpine plants, our study investigated whether the Q10 of leaf respiration differs between the day and night.
We characterised diurnal RL and RD from 15 to 35 °C, and RN from 10 to 25 °C at night, in four common herbaceous species widely distributed in alpine meadows on the Qinghai-Tibetan Plateau. We measured leaf temperature every second for 24 h over a period of 18 days. By combining leaf temperature with respiratory physiological measurements, we calculated leaf carbon loss to assess the consequences of differences in temperature response of leaf respiration between day and night.
RN exhibited a higher Q10 than RL and RD by about one third. Although there were no significant differences in Q10 between RL and RD, light inhibition of leaf respiration (i.e. 100 % - RL / RD) was at its lowest at a moderate leaf temperature (22−25 °C). G. straminea and S. pulchra showed lower levels of inhibition than L. sagitta and L. virgaurea. Respiratory carbon loss (Closs_day) based on RN exceeded Closs_day based on RL by up to 47 %, which varied considerably between the species.
These results suggest that the temperature sensitivity (Q10) of leaf respiration differs significantly between day and night, a finding that needs to be taken into account when modelling the diel rates of respiratory carbon loss in plants, especially at high altitudes and some high latitudes with a large diurnal variation and low mean temperature. Therefore, considering that neither RN nor RD can accurately represent RL, we strongly recommend that the observations of RL should be prioritized when estimating daytime leaf carbon loss.
{"title":"Differential temperature responses of diurnal and nocturnal leaf respiration in four alpine herbaceous species","authors":"Tianyu Zheng , Huixing Kang , Yuan Yu , Tong Guo , Xinran Ke , Owen K. Atkin , Yanhong Tang","doi":"10.1016/j.agrformet.2025.110385","DOIUrl":"10.1016/j.agrformet.2025.110385","url":null,"abstract":"<div><div>Current estimates of diel respiratory carbon release depend on accurate predictions of the temperature sensitivity (<em>Q</em><sub>10</sub>) of leaf respiration during the day and night. Such predictions typically rely on measurements of the <em>Q</em><sub>10</sub> of respiration in the light (<em>R</em><sub>L</sub>) and dark (<em>R</em><sub>D</sub>) made during the day, and assuming that the <em>Q</em><sub>10</sub> of nocturnal respiration (<em>R</em><sub>N</sub>) equals that of <em>R</em><sub>D</sub>. Using <em>R</em><sub>D</sub> as a surrogate for <em>R</em><sub>N</sub>, however, creates errors in estimates of diel respiration whenever the <em>Q</em><sub>10</sub> of <em>R</em><sub>D</sub> and <em>R</em><sub>N</sub> differ. Using measurements made on field-grown, high-altitude alpine plants, our study investigated whether the <em>Q</em><sub>10</sub> of leaf respiration differs between the day and night.</div><div>We characterised diurnal <em>R</em><sub>L</sub> and <em>R</em><sub>D</sub> from 15 to 35 °C, and <em>R</em><sub>N</sub> from 10 to 25 °C at night, in four common herbaceous species widely distributed in alpine meadows on the Qinghai-Tibetan Plateau. We measured leaf temperature every second for 24 h over a period of 18 days. By combining leaf temperature with respiratory physiological measurements, we calculated leaf carbon loss to assess the consequences of differences in temperature response of leaf respiration between day and night.</div><div><em>R</em><sub>N</sub> exhibited a higher <em>Q</em><sub>10</sub> than <em>R</em><sub>L</sub> and <em>R</em><sub>D</sub> by about one third. Although there were no significant differences in <em>Q</em><sub>10</sub> between <em>R</em><sub>L</sub> and <em>R</em><sub>D</sub>, light inhibition of leaf respiration (i.e. 100 % - <em>R</em><sub>L</sub> / <em>R</em><sub>D</sub>) was at its lowest at a moderate leaf temperature (22−25 °C). <em>G. straminea</em> and <em>S. pulchra</em> showed lower levels of inhibition than L. <em>sagitta</em> and L. <em>virgaurea</em>. Respiratory carbon loss (C<sub>loss_day</sub>) based on <em>R</em><sub>N</sub> exceeded C<sub>loss_day</sub> based on <em>R</em><sub>L</sub> by up to 47 %, which varied considerably between the species.</div><div>These results suggest that the temperature sensitivity (<em>Q</em><sub>10</sub>) of leaf respiration differs significantly between day and night, a finding that needs to be taken into account when modelling the diel rates of respiratory carbon loss in plants, especially at high altitudes and some high latitudes with a large diurnal variation and low mean temperature. Therefore, considering that neither <em>R</em><sub>N</sub> nor <em>R</em><sub>D</sub> can accurately represent <em>R</em><sub>L</sub>, we strongly recommend that the observations of <em>R</em><sub>L</sub> should be prioritized when estimating daytime leaf carbon loss.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110385"},"PeriodicalIF":5.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-06DOI: 10.1016/j.agrformet.2025.110383
Lihong Wu , Hao Quan , Hao Feng , Dianyuan Ding , Lina Wu , De Li Liu , Bin Wang
Adjusting sowing dates and rates are effective measures for winter wheat to adapt to future climate change in achieving high yields. However, the combined influence of sowing date and sowing rate on winter wheat yield and water use efficiency (WUE) under plastic mulching (PM) conditions, particularly in the context of climate change, remains unexplored. To address this, a two-year field experiment conducted in the Guanzhong Plain, Northwest China, was used to calibrate the SPACSYS model. The calibrated model, driven by 27 global climate models under SSP245 and SSP585 scenarios, was used to project changes in yield and WUE and to evaluate the potential of various management strategies for mitigating the adverse effects of climate change. We investigated multiple strategies, including two mulching methods [plastic mulching (PM) and no mulching (NM)], six sowing rates (R1: local; R2: 110 % R1; R3: 120 % R1; R4: 130 % R1; R5: 140 % R1; R6: 150 % R1), and four sowing dates (10-day early, normal sowing, 10-day delay, 20-day delay). Results showed that without adaptation, the simulated yield under local management options (NM+normal sowing date+R1 sowing rate) decreased by 14.9−26.7 % under SSP245 and by 24.5−39.5 % under SSP585. Similarly, WUE decreased by 10.4−12.5 % under SSP245 and by 3.2−7.0 % under SSP585. These reductions in yield were primarily attributed to rising temperatures and decreasing radiation, while the decline in WUE was mainly driven by rising temperatures. In contrast, the optimal management combination (PM+10-day delayed sowing+R5 sowing rate) resulted in yield increases of 26.0−34.7 % under SSP245 and 21.2−32.5 % under SSP585 compared to the local management during the baseline period. This strategy also achieved the highest WUE, improving by 31.0−32.7 % under SSP245 and 36.5−39.2 % under SSP585 relative to the baseline. These findings provide valuable information to help farmers in Northwest China adapt to future climate change by optimizing sowing time and rate with PM, thereby enhancing wheat yield and WUE.
{"title":"Delaying sowing time and increasing sowing rate with plastic mulching can enhance wheat yield and water use efficiency under future climate change","authors":"Lihong Wu , Hao Quan , Hao Feng , Dianyuan Ding , Lina Wu , De Li Liu , Bin Wang","doi":"10.1016/j.agrformet.2025.110383","DOIUrl":"10.1016/j.agrformet.2025.110383","url":null,"abstract":"<div><div>Adjusting sowing dates and rates are effective measures for winter wheat to adapt to future climate change in achieving high yields. However, the combined influence of sowing date and sowing rate on winter wheat yield and water use efficiency (WUE) under plastic mulching (PM) conditions, particularly in the context of climate change, remains unexplored. To address this, a two-year field experiment conducted in the Guanzhong Plain, Northwest China, was used to calibrate the SPACSYS model. The calibrated model, driven by 27 global climate models under SSP245 and SSP585 scenarios, was used to project changes in yield and WUE and to evaluate the potential of various management strategies for mitigating the adverse effects of climate change. We investigated multiple strategies, including two mulching methods [plastic mulching (PM) and no mulching (NM)], six sowing rates (R1: local; R2: 110 % R1; R3: 120 % R1; R4: 130 % R1; R5: 140 % R1; R6: 150 % R1), and four sowing dates (10-day early, normal sowing, 10-day delay, 20-day delay). Results showed that without adaptation, the simulated yield under local management options (NM+normal sowing date+R1 sowing rate) decreased by 14.9−26.7 % under SSP245 and by 24.5−39.5 % under SSP585. Similarly, WUE decreased by 10.4−12.5 % under SSP245 and by 3.2−7.0 % under SSP585. These reductions in yield were primarily attributed to rising temperatures and decreasing radiation, while the decline in WUE was mainly driven by rising temperatures. In contrast, the optimal management combination (PM+10-day delayed sowing+R5 sowing rate) resulted in yield increases of 26.0−34.7 % under SSP245 and 21.2−32.5 % under SSP585 compared to the local management during the baseline period. This strategy also achieved the highest WUE, improving by 31.0−32.7 % under SSP245 and 36.5−39.2 % under SSP585 relative to the baseline. These findings provide valuable information to help farmers in Northwest China adapt to future climate change by optimizing sowing time and rate with PM, thereby enhancing wheat yield and WUE.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110383"},"PeriodicalIF":5.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-06DOI: 10.1016/j.agrformet.2025.110382
Zhe Kong , Tiejun Wang , Qiong Han , Yibin Dai , Yutao Zuo , Lichun Wang , Yunchao Lang
Ecosystem water use efficiency (eWUE = gross primary production (GPP)/evapotranspiration (ET)) is widely used to characterize the coupling of ecosystem water and carbon processes. To investigate how eWUE responds to environmental changes, we compared environmental controls on annual, monthly, and daily GPP, ET, and eWUE from diverse ecosystems and climate regimes and quantified their daily relative impacts with machine learning techniques. Similar to GPP and ET, eWUE was strongly related to environmental variables at daily and monthly scales than at annual scales, indicating the tighter interplays of ecosystem processes with surroundings at shorter timescales. More critically, daily GPP and ET variations were primarily driven by net radiation (Rn) at most sites; whereas, vapor pressure deficit (VPD) dominated daily eWUE variations from humid to semi-arid sites, leaf area index (LAI) controlled eWUE variations at arid sites. It was largely attributed to the asynchronous responses of daily GPP and ET to environmental variables: the positive responses (though with different degrees) of daily GPP and ET to Rn weakened the Rn impact on eWUE; whereas, the opposite responses of daily GPP (negative) and ET (positive) to VPD enhanced the VPD impact on eWUE. The greater LAI impact on daily eWUE at arid sites was due to the dominant control of LAI on GPP variations under arid conditions. Unlike early eWUE models that incorporate VPD, our data showed that Rn could significantly improve eWUE models. This work provides valuable insights into understanding the controlling mechanisms of eWUE and ameliorating the representation of GPP and ET coupling.
生态系统水利用效率(eWUE = gross primary production （GPP)/evapotranspiration (ET)）被广泛用于表征生态系统水碳耦合过程。为了研究eWUE如何响应环境变化，我们比较了不同生态系统和气候条件下的年度、月度和每日GPP、ET和eWUE的环境控制，并使用机器学习技术量化了它们的日常相对影响。与GPP和ET相似，eWUE在日和月尺度上与环境变量的相关性强于年尺度，表明生态系统过程与环境的相互作用在较短的时间尺度上更为紧密。更重要的是，在大多数站点，GPP和ET的日变化主要由净辐射（Rn）驱动；水汽压亏缺（VPD）主导湿润至半干旱区土壤水分利用效率的日变化，叶面积指数（LAI）控制干旱区土壤水分利用效率的日变化。这在很大程度上归因于日GPP和ET对环境变量的非同步响应：日GPP和ET对Rn的正响应（尽管程度不同）减弱了Rn对生态高效利用的影响；而日GPP（负）和ET（正）对VPD的相反响应增强了VPD对eWUE的影响。LAI对干旱样地日生态利用效率的影响较大，主要是由于LAI对干旱条件下GPP变化的主导控制。与早期纳入VPD的eWUE模型不同，我们的数据表明，Rn可以显著改善eWUE模型。这项工作为理解eWUE的控制机制和改进GPP和ET耦合的表示提供了有价值的见解。
{"title":"Impacts of environmental factors on ecosystem water use efficiency: An insight from gross primary production and evapotranspiration dynamics","authors":"Zhe Kong , Tiejun Wang , Qiong Han , Yibin Dai , Yutao Zuo , Lichun Wang , Yunchao Lang","doi":"10.1016/j.agrformet.2025.110382","DOIUrl":"10.1016/j.agrformet.2025.110382","url":null,"abstract":"<div><div>Ecosystem water use efficiency (eWUE = gross primary production (GPP)/evapotranspiration (ET)) is widely used to characterize the coupling of ecosystem water and carbon processes. To investigate how eWUE responds to environmental changes, we compared environmental controls on annual, monthly, and daily GPP, ET, and eWUE from diverse ecosystems and climate regimes and quantified their daily relative impacts with machine learning techniques. Similar to GPP and ET, eWUE was strongly related to environmental variables at daily and monthly scales than at annual scales, indicating the tighter interplays of ecosystem processes with surroundings at shorter timescales. More critically, daily GPP and ET variations were primarily driven by net radiation (R<sub>n</sub>) at most sites; whereas, vapor pressure deficit (VPD) dominated daily eWUE variations from humid to semi-arid sites, leaf area index (LAI) controlled eWUE variations at arid sites. It was largely attributed to the asynchronous responses of daily GPP and ET to environmental variables: the positive responses (though with different degrees) of daily GPP and ET to R<sub>n</sub> weakened the R<sub>n</sub> impact on eWUE; whereas, the opposite responses of daily GPP (negative) and ET (positive) to VPD enhanced the VPD impact on eWUE. The greater LAI impact on daily eWUE at arid sites was due to the dominant control of LAI on GPP variations under arid conditions. Unlike early eWUE models that incorporate VPD, our data showed that R<sub>n</sub> could significantly improve eWUE models. This work provides valuable insights into understanding the controlling mechanisms of eWUE and ameliorating the representation of GPP and ET coupling.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110382"},"PeriodicalIF":5.6,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-03DOI: 10.1016/j.agrformet.2025.110381
Yiting Chen , Kehao Liang , Bingjing Cui , Jingxiang Hou , Eva Rosenqvist , Liang Fang , Fulai Liu
Drought and heat stress often occur simultaneously causing detrimental impacts on crop growth and physiology. Stomata behave differently when plants are exposed to drought and heat stress, which may change the coupling relationship of stomatal conductance (gs) and photosynthesis (An) and thereby influence the capability of the Ball-Berry (BB)-based gs model. To examine the prevalence of this gs-An decoupling and its influence on the predictability of gs model, three pot experiments in climate-controlled greenhouses or climate chambers were conducted where leaf gas exchange of four wheat genotypes with varied sensitivity to drought or heat stress was measured, and the performance of the unified stomatal optimization model (USO model) in simulating gs under individual or combined stress was evaluated. Data obtained from 2019 were used for model parameterization and from 2020 to 2023 were used for model validation. Results showed that the gs-An decoupling only occurred in well-watered plants under heat regardless of genotype, where the original USO model underestimated the gs. To improve the model prediction, a new slope parameter, which based on the differential effect of the relative stomatal (ls) and non-stomatal limitations (lns) on An, with respect to leaf temperature was incorporated to modify the USO model. Compared with the original USO model, the modified USO model showed lower Akaike's information criterion and improved predictability for gs with higher R2 (> 0.90), lower RMSE (< 0.08) and MAE (< 0.06). These findings underscore the critical importance of integrating the effect of leaf temperature on the ls and lns into the USO model for accurately predicting gs in wheat plants subjected to heat stress.
{"title":"Incorporating the temperature responses of stomatal and non-stomatal limitations to photosynthesis improves the predictability of the unified stomatal optimization model for wheat under heat stress","authors":"Yiting Chen , Kehao Liang , Bingjing Cui , Jingxiang Hou , Eva Rosenqvist , Liang Fang , Fulai Liu","doi":"10.1016/j.agrformet.2025.110381","DOIUrl":"10.1016/j.agrformet.2025.110381","url":null,"abstract":"<div><div>Drought and heat stress often occur simultaneously causing detrimental impacts on crop growth and physiology. Stomata behave differently when plants are exposed to drought and heat stress, which may change the coupling relationship of stomatal conductance (<em>g</em><sub>s</sub>) and photosynthesis (<em>A</em><sub>n</sub>) and thereby influence the capability of the Ball-Berry (BB)-based <em>g</em><sub>s</sub> model. To examine the prevalence of this <em>g</em><sub>s</sub>-<em>A</em><sub>n</sub> decoupling and its influence on the predictability of <em>g</em><sub>s</sub> model, three pot experiments in climate-controlled greenhouses or climate chambers were conducted where leaf gas exchange of four wheat genotypes with varied sensitivity to drought or heat stress was measured, and the performance of the unified stomatal optimization model (USO model) in simulating <em>g</em><sub>s</sub> under individual or combined stress was evaluated. Data obtained from 2019 were used for model parameterization and from 2020 to 2023 were used for model validation. Results showed that the <em>g</em><sub>s</sub>-<em>A</em><sub>n</sub> decoupling only occurred in well-watered plants under heat regardless of genotype, where the original USO model underestimated the <em>g</em><sub>s</sub>. To improve the model prediction, a new slope parameter, which based on the differential effect of the relative stomatal (<em>l</em><sub>s</sub>) and non-stomatal limitations (<em>l</em><sub>ns</sub>) on <em>A</em><sub>n</sub>, with respect to leaf temperature was incorporated to modify the USO model. Compared with the original USO model, the modified USO model showed lower Akaike's information criterion and improved predictability for <em>g</em><sub>s</sub> with higher <em>R</em><sup>2</sup> (> 0.90), lower RMSE (< 0.08) and MAE (< 0.06). These findings underscore the critical importance of integrating the effect of leaf temperature on the <em>l</em><sub>s</sub> and <em>l</em><sub>ns</sub> into the USO model for accurately predicting <em>g</em><sub>s</sub> in wheat plants subjected to heat stress.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110381"},"PeriodicalIF":5.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142917022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-02DOI: 10.1016/j.agrformet.2024.110380
Tonghong Wang , Xufeng Wang , Qiang Zhang , Songlin Zhang , Junlei Tan , Yang Zhang , Zhiguo Ren , Yanpeng Yang , Tao Che
The terrestrial carbon cycle is strongly influenced by climate changes, but the impact of extreme temperature events on carbon fluxes in Northwest China's ecosystems remains poorly understood. To understand the impacts of extreme temperature events on carbon fluxes, we measured net ecosystem productivity (NEP), gross primary productivity (GPP), and ecosystem respiration (Reco) along with meteorological factors at nine sites in the Heihe River Basin (HRB) from 2013 to 2022. Extreme high temperature (EHT) and extreme low temperature (ELT) were identified based on long-term air temperature data and their impacts on carbon fluxes were examined. Our findings indicate a rising frequency of EHT events and a decline in ELT events during the growing seasons over the past decade. During the EHT periods, GPP and Reco generally increased, regardless of soil water content. In contrast, both GPP and Reco decreased during the ELT periods. Alpine grasslands are more sensitive to EHT events, while deserts exhibit more sensitivity to ELT events. These results highlight the diverse responses of carbon fluxes to extreme temperature events across ecosystems in the HRB, providing valuable insights for regional ecosystem management and climate change adaptation.
{"title":"Effects of extreme temperature events on carbon fluxes in different ecosystems in the Heihe River Basin, China","authors":"Tonghong Wang , Xufeng Wang , Qiang Zhang , Songlin Zhang , Junlei Tan , Yang Zhang , Zhiguo Ren , Yanpeng Yang , Tao Che","doi":"10.1016/j.agrformet.2024.110380","DOIUrl":"10.1016/j.agrformet.2024.110380","url":null,"abstract":"<div><div>The terrestrial carbon cycle is strongly influenced by climate changes, but the impact of extreme temperature events on carbon fluxes in Northwest China's ecosystems remains poorly understood. To understand the impacts of extreme temperature events on carbon fluxes, we measured net ecosystem productivity (NEP), gross primary productivity (GPP), and ecosystem respiration (Reco) along with meteorological factors at nine sites in the Heihe River Basin (HRB) from 2013 to 2022. Extreme high temperature (EHT) and extreme low temperature (ELT) were identified based on long-term air temperature data and their impacts on carbon fluxes were examined. Our findings indicate a rising frequency of EHT events and a decline in ELT events during the growing seasons over the past decade. During the EHT periods, GPP and Reco generally increased, regardless of soil water content. In contrast, both GPP and Reco decreased during the ELT periods. Alpine grasslands are more sensitive to EHT events, while deserts exhibit more sensitivity to ELT events. These results highlight the diverse responses of carbon fluxes to extreme temperature events across ecosystems in the HRB, providing valuable insights for regional ecosystem management and climate change adaptation.</div></div>","PeriodicalId":50839,"journal":{"name":"Agricultural and Forest Meteorology","volume":"362 ","pages":"Article 110380"},"PeriodicalIF":5.6,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142916839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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