Theodoros Mavrommatis | Aristotle University of Thessaloniki (original) (raw)
Papers by Theodoros Mavrommatis
Land
Yield estimations at global or regional spatial scales have been compromised due to poor crop mod... more Yield estimations at global or regional spatial scales have been compromised due to poor crop model calibration. A methodology for estimating the genetic parameters related to grain growth and yield for the CERES-Wheat crop model is proposed based on yield gap concept, the GLUE coefficient estimator, and the global yield gap atlas (GYGA). Yield trials with three durum wheat cultivars in an experimental farm in northern Greece from 2004 to 2010 were used. The calibration strategy conducted with CERES-Wheat (embedded in DSSAT v.4.7.5) on potential mode taking into account the year-to-year variability of relative yield gap Yrg (YgC_adj) was: (i) more effective than using the average site value of Yrg (YgC_unadj) only (the relative RMSE ranged from 10 to 13% for the YgC_adj vs. 48 to 57% for YgC_unadj) and (ii) superior (slightly inferior) to the strategy conducted with DSSAT v.4.7.5 (DSSAT v.3.5—relative RMSE of 5 to 8% were found) on rainfed mode. Earlier anthesis, maturity, and decre...
Sustainability
This study presents an updated assessment of the projected climate change over Greece in the near... more This study presents an updated assessment of the projected climate change over Greece in the near future (2021–2050) and at the end of the 21st century (2071–2100) (EOC), relative to the reference period 1971–2000, and focusing on seasonal crop-specific climatic indices. The indices include days (d) with: a maximum daily near-surface temperature (TASMAX) > 30 °C in Spring, a TASMAX > 35 °C in Summer (hot days), a minimum daily near-surface temperature (TASMIN) < 0 °C (frost days) in Spring, a TASMIN > 20 °C (tropical nights) in Spring–Summer and the daily precipitation (PR) > 1 mm (wet days) in Spring and Summer covering the critical periods in which wheat, tomatoes, cotton, potato, grapes, rice and olive are more sensitive to water and/or temperature stress. The analysis is based on an ensemble of 11 EURO-CORDEX regional climate model simulations under the influence of a strong, a moderate, and a no mitigation Representative Concentration Pathway (RCP2.6, RCP4.5 and ...
Water
Reanalysis datasets are among the most used gridded data for the study of weather and climate [...]
Researchers frequently use crop simulation models to estimate the impacts of climate change on ag... more Researchers frequently use crop simulation models to estimate the impacts of climate change on agricultural production. While most models used for this purpose have been validated thoroughly at the research plot level, few studies have evaluated them for multiple years and sites and with inputs commonly used in climate impact studies. Here, we examine how well CROPGRO-Soybean performs across space and time using cultivar coefficients provided with the model, estimates of solar radiation, and soil inputs that were estimated from readily available soil surveys. Modeled yield for three maturity groups was compared with that observed from 8 to 23 yr at eight agricultural experiment stations in the southeastern United States. The model was evaluated tvith respect to its ability to replicate the mean and standard deviation of observed yield. The mean squared deviation (MSD), weighted according to the number of years at each station, was 0.42 (Mg ha'9)1. The model simulated mean yield...
Alex Ruane, Sonali McDermid, Nicholas Hudson, Cynthia Rosenzweig, L. R. Ahuja, Saseendran S. Anap... more Alex Ruane, Sonali McDermid, Nicholas Hudson, Cynthia Rosenzweig, L. R. Ahuja, Saseendran S. Anapalli, Jakarat Anothai, Senthold Asseng, Dumont Benjamin, Federico Bert, Patrick Bertuzzi, Virendra S. Bhatia, Marco Bindi, Ian Broad, Davide Cammarano, Ramiro Carretero, Uran Chung, Giacomo De Sanctis, Thanda Dhliwayo, Frank Ewert, Roberto Ferrise, Thomas Gaiser, Guillermo Garcia, Sika Gbegbelegbe, Vellingiri Geethalakshmi, Edward Gerardeaux, Richard Goldberg, Brian Grant, Edgardo Guevara, Holger Hoffmann, Huanping Huang, Flavio Barbosa Justino, Asha S. Karunaratne, Ann-Kristin Koehler, Soora Naresh Kumar, Arunachalam Lakshmanan, Xiaomao Lin, Qunying Luo, Graciela Magrin, Yuji Masutomi, Theodoros Mavromatis, Greg McLean, Santiago Meira, Monoranjan Mohanty, Marco Moriondo, Lamyaa Negm, Francesca Orlando, Isik Ozturk, Zhiming Qi, Johanna Ramarohetra, Helene Raynal, Gabriel Rodriguez, Vaishali Sharda, Lu Shuo, Ward Smith, Afshin Soltani, K.Srinivas, Dillip Kumar Swain, Fulu Tao, Kindie Tesf...
Recognizing that climate change will affect agricultural systems both through mean changes and th... more Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of cli...
International Journal of Climatology, 2020
Gridded climate datasets are among the most used datasets in the study of weather and climate. Gi... more Gridded climate datasets are among the most used datasets in the study of weather and climate. Given the large range of such products currently available, investigators must consider their strengths and weaknesses. This research evaluated the comparative performance of two reanalysis datasets (ERA‐Interim, and Agri4Cast [e.g. MARS‐STAT]) and one reprocessing dataset (E‐OBS) in replicating selected spatiotemporal characteristics of precipitation and drought at 20 wine production regions in Greece during 1981–2012. The results highlighted the abilities of E‐OBS and Agri4Cast, whose performance varied with season and the specific rainfall characteristic in question. The former product: (1) reproduced better the annual decreasing trends in spring, summer, and autumn, (2) captured a larger portion of the observed monthly variability in spring and summer, associated better and showed the lowest errors with observations, and (3) computed better or equal to Agri4Cast different skill scores applied on the daily time series, replicated better the probabilities of wet and dry days and equally well with Agri4Cast the extreme precipitation indices. Agri4Cast replicated better the monthly cycle of precipitation (underestimating though the station averages) and the increasing trend from SE to NW, on spatial basis. With regards to drought monitoring, frequency and detection of very and extremely wet and dry spells, SPI was superior to SC‐PDSI (the self‐calibrated version of Palmer's index), particularly when E‐OBS data was used. Agri4Cast and E‐OBS are the most appropriate products for use in climate/atmospheric‐related research over Greece.
OENO One, 2020
Aim: This research aimed to: (1) investigate the relationships between harvest dates and berry co... more Aim: This research aimed to: (1) investigate the relationships between harvest dates and berry composition with air temperature during important periods during the growing season, across a range of indigenous and international winegrape varieties grown in wine regions over the majority of Greece; (2) calculate growing degree-days (GDD) from 1st of April until the harvest date of each variety and group the winegrape varieties according to their heat requirements; and (3) predict future harvest dates based upon these heat requirements under different representative emission pathways (i.e., RCP4.5 and RCP8.5) and future time periods (2041-2065 and 2071-2095) using an ensemble projection dataset.Methods and results: The analysis of heat requirements based on GDD from 1st of April to harvest date identified consistent maturity groups of the varieties studied, especially for indigenous Greek varieties. Trend analysis using the basic linear regression model showed that harvest dates have s...
Scientia Horticulturae, 2021
Abstract Extreme rainfall events pose a threating factor for the income of growers, processing in... more Abstract Extreme rainfall events pose a threating factor for the income of growers, processing industry and communities; however little is known on damages caused on peach trees. The pattern of historical trends in precipitation and the Standardized Precipitation Index (SPI) characteristics during the summer months were studied in Naoussa, Northern Greece. Damages from naturally occurring summer rainfalls were recorded in a peach and nectarine cultivar evaluation orchard and effects from a simulated rainfall experiment using prolonged (100 mm in 3 days) and intense (100 mm in 1 day) rainfall treatments were monitored on peach cv. ‘Elegant Lady’ trees. Results showed that during the summer months of 1967–2019, there was no significant effect in the precipitation totals and the Standardized Precipitation Index (SPI) characteristics, although an increase in the frequency of wet spells is noticeable in the last three years. Fruit drop and symptoms of skin streaking, bronzing, and collapse in skin tissue of peach and nectarine cultivars close to maturity initiated during and continued after the end of severe and extreme wet spells of three or more consecutive rainy days in a summer month in 2017, 2018 (total ca. 100 mm) and 2019 (total 54 mm) were recorded. The type of skin damages differed among peach and nectarine cultivars. Greater extent of damages was documented in the peach cvs ‘Kevina®’, ‘Maura®’ and ‘Royal Time®’ and fewer damages in ‘Red Haven’, and ‘Sweet Scarlet’. The rainfall simulation experiment showed that only the prolonged, and not the intense treatment, caused fruit drop starting two days after the treatment initiation and lasted three days after the end, while streaking symptoms developed mostly in fruit from the prolonged rainfall treatment. In conclusion, the consecutive wet days rather than the total rainfall caused fruit drop and skin damages in peach and nectarine fruits close to harvest, while cultivars differed in the type of damage developing. Insurance programs need to be readdressed, incorporating rainfall frequency rather than total monthly rainfall as indicators of yield, as well as including the symptoms of fruit drop, skin streaking, bronzing and collapse as damages rather than cracking in peach and nectarine.
We use the CERES family of crop models to assess the effect of different spatial scales of climat... more We use the CERES family of crop models to assess the effect of different spatial scales of climate change scenarios on the simulated yield changes of maize (Zea mays L.), winter wheat (Triticum aestivum L.), and rice (Oryza sativa L.) in the Southeastern United States. The climate change scenarios were produced with the control and doubled CO2 runs of a high resolution regional climate model and a coarse resolution general circulation model, which provided the initial and lateral boundary conditions for the regional model. When considering the effect of climate change only at the individual state level, maize yields decreased in all states for both scenarios (─5 to ─29%), but the differences in yields between the two scenarios were generally significant, the coarse scale showing the larger decreases. Winter wheat yield decreases (─27 to ─48%) were larger than those for maize but the differences in yields produced by the two climate change scenarios were insignificant in most states....
Theoretical and Applied Climatology, 2014
Notwithstanding technological developments, agricultural production is still affected by uncontro... more Notwithstanding technological developments, agricultural production is still affected by uncontrollable factors, such weather and climate. Within this context, the present study aims at exploring the relative influence of growing season climate on the yields of major cereals (hard and soft wheat, maize, and barley) on a regional scale in Greece. To this end, crop-climate relationships and the impacts of climate trends over the period 1978-2005 were explored using linear regression and change point analysis (CPA). Climate data used include maximum (Tx) and minimum temperature (Tn), diurnal temperature range (Tr), precipitation (Prec), and solar radiation (Rad). Temperature effects were the most substantial. Yields reduced by 1.8-7.1 %/°C with increasing Tx and by 1.4-6.1 %/°C with decreasing Tr. The warming trends of Tn caused bilateral yield effects (from −3.7 to 8.4 %/°C). The fewer significantly increasing Rad and decreasing Prec anomalies were associated with larger yield decreases (within the range of 2.2 % MJ/m 2 /day (for maize) to 4.9 % MJ/m 2 /day (for hard wheat)) and smaller yield increases (from 0.04 to 1.4 %/mm per decade), respectively. Wheat and barley-the most vulnerable cereals-were most affected by the trends of extreme temperatures and least by Tr. On the contrary, solar radiation has proven to be the least affecting climate variable on all cereals. Despite the similarity in the direction of crop responses with both analyses, yield changes were much more substantial in the case of CPA analysis. In conclusion, regional climate change has affected Greek cereal productivity, in a few, but important for cereal production, regions. The results of this study are expected to be valuable in anticipating the effects of weather/climate on other warm regions worldwide, where the upper temperature limit for some cereals and further changes in climate may push them past suitability for their cultivation.
Handbook of Climate Change and Agroecosystems, 2015
International Journal of Climatology, 2013
Climate characteristics and relationships with indigenous varieties in Greece are examined to bet... more Climate characteristics and relationships with indigenous varieties in Greece are examined to better understand how these varieties perform in their native climate and assess the impact regional climate change has on the Greek wine industry. Thus, harvest dates (ΔH) for eight indigenous varieties and regions, along with climate data, were gathered and systematically explored using linear regression models and principal component analysis for three ‘effective’ growing season time period definitions (calendar year, growing season and ripening period). The eight study regions had marked differences in their general climatic characteristics, mainly between mainland and island areas. ΔH response was not particularly sensitive to time period definition. In five out of eight regions, a systematic shift of ΔH was identified (earlier harvest), mainly driven by changes in maximum and minimum temperatures. Significant trends in climate parameters and viticulture–climate relationships were more evident for island regions when compared to mainland locations. Moreover, areas with late ripening varieties were shown to be less sensitive to climate changes. Only in one region harvest was delayed, possibly due to non‐climate factors. The identification of up‐to‐date climate and grapevine phenology relationships could be an important step for broader and more confident future assessments of climate suitability for viticulture and climate change impacts in Greece, and provide insights into how lesser known varieties might perform in other regions.
Climate Research, 2008
Lack of data on site-specific daily solar radiation (R g) is a significant impediment for most cr... more Lack of data on site-specific daily solar radiation (R g) is a significant impediment for most crop modeling applications. For this reason, 5 methods for estimating R g were tested: the Ångström-Prescott equation (AP), the Supit-van Kappel formula (SK) and 3 temperature-based methods: Campbell-Donatelli model, Hargreaves equation, and piecewise multiple linear regressions with a breakpoint (PLR). To overcome the lack of long and continuous time series of R g measurements at multiple sites, satellite-derived R g from the HelioClim-1 database were tested against observations from 2 stations, and then interpolated for 12 additional stations. When sunshine duration data were available, the AP equation was best, because it (1) produced intercepts and slopes closest to zero and unity, respectively and (2) had the lowest relative RMSE (9 to 18.6%). When cloud cover observations and data on maximum and minimum temperatures were available, the SK equation was equally effective as AP in most assessment metrics. When the only data for a site were daily maximum and minimum temperatures, the PLR approach with a breakpoint, which reflects the value at which the response of daily R g changes as a function of the extraterrestrial solar radiation R A and the diurnal temperature range, performed best. The mean relative RMSE of the PLR approach was < 3.7% higher than that of AP. The SK equation provided the most suitable simulation of measured R g for the CERES-Wheat crop model, while among the temperature-based methods PLR produced the smallest yield errors. Future validation efforts should explore the validity of the PLR model in other regions and under regimes with greater availability of R g data
Climate Research, 2005
Lack of site-specific global solar radiation (GSR) data is a significant impediment for most crop... more Lack of site-specific global solar radiation (GSR) data is a significant impediment for most crop model applications. First, several empirical methods for estimating GSR from observed maximum and minimum temperature were evaluated using data from urban (National Climatic Data Center [NCDC] data set) and rural (Florida Automated Weather Network [FAWN] data set) sites in Florida. Next, the spatial structure of empirical model parameters was investigated and the possibility of employing spatially interpolated coefficients developed at urban or rural sites to predict solar radiation at rural locations, where most crops are grown and often crop modeling is required to address various issues, was assessed. Finally, the effects of observed and estimated GSR on simulated potential yield and evapotranspiration with CROPGRO-Peanut and CERES-Maize models at 6 crop-location combinations were evaluated. The model developed by Donatelli and Bellocchi (DB) achieved the most accurate estimations of GSR across Florida. The quality of those predictions varied with environment setting (urban-rural) and latitude. RMSE (root mean square error) between observed and fitted daily GSR were in the range of 3.1-4.1 and 3.2-4.9 MJ m-2 d-1 for FAWN and NCDC evaluation subsets , respectively. Radiation for FAWN sites was efficiently estimated by the coefficients interpolated from rural sites but was substantially overestimated by 17.6%, on monthly basis, when urban sites supplied the model empirical parameters. NCDC sites were site specific and suitable sources of solar radiation at urban environments only. Input of estimated with the DB model GSR into a crop model would be a realistic option at sites where only temperature and precipitation are available.
Land
Yield estimations at global or regional spatial scales have been compromised due to poor crop mod... more Yield estimations at global or regional spatial scales have been compromised due to poor crop model calibration. A methodology for estimating the genetic parameters related to grain growth and yield for the CERES-Wheat crop model is proposed based on yield gap concept, the GLUE coefficient estimator, and the global yield gap atlas (GYGA). Yield trials with three durum wheat cultivars in an experimental farm in northern Greece from 2004 to 2010 were used. The calibration strategy conducted with CERES-Wheat (embedded in DSSAT v.4.7.5) on potential mode taking into account the year-to-year variability of relative yield gap Yrg (YgC_adj) was: (i) more effective than using the average site value of Yrg (YgC_unadj) only (the relative RMSE ranged from 10 to 13% for the YgC_adj vs. 48 to 57% for YgC_unadj) and (ii) superior (slightly inferior) to the strategy conducted with DSSAT v.4.7.5 (DSSAT v.3.5—relative RMSE of 5 to 8% were found) on rainfed mode. Earlier anthesis, maturity, and decre...
Sustainability
This study presents an updated assessment of the projected climate change over Greece in the near... more This study presents an updated assessment of the projected climate change over Greece in the near future (2021–2050) and at the end of the 21st century (2071–2100) (EOC), relative to the reference period 1971–2000, and focusing on seasonal crop-specific climatic indices. The indices include days (d) with: a maximum daily near-surface temperature (TASMAX) > 30 °C in Spring, a TASMAX > 35 °C in Summer (hot days), a minimum daily near-surface temperature (TASMIN) < 0 °C (frost days) in Spring, a TASMIN > 20 °C (tropical nights) in Spring–Summer and the daily precipitation (PR) > 1 mm (wet days) in Spring and Summer covering the critical periods in which wheat, tomatoes, cotton, potato, grapes, rice and olive are more sensitive to water and/or temperature stress. The analysis is based on an ensemble of 11 EURO-CORDEX regional climate model simulations under the influence of a strong, a moderate, and a no mitigation Representative Concentration Pathway (RCP2.6, RCP4.5 and ...
Water
Reanalysis datasets are among the most used gridded data for the study of weather and climate [...]
Researchers frequently use crop simulation models to estimate the impacts of climate change on ag... more Researchers frequently use crop simulation models to estimate the impacts of climate change on agricultural production. While most models used for this purpose have been validated thoroughly at the research plot level, few studies have evaluated them for multiple years and sites and with inputs commonly used in climate impact studies. Here, we examine how well CROPGRO-Soybean performs across space and time using cultivar coefficients provided with the model, estimates of solar radiation, and soil inputs that were estimated from readily available soil surveys. Modeled yield for three maturity groups was compared with that observed from 8 to 23 yr at eight agricultural experiment stations in the southeastern United States. The model was evaluated tvith respect to its ability to replicate the mean and standard deviation of observed yield. The mean squared deviation (MSD), weighted according to the number of years at each station, was 0.42 (Mg ha'9)1. The model simulated mean yield...
Alex Ruane, Sonali McDermid, Nicholas Hudson, Cynthia Rosenzweig, L. R. Ahuja, Saseendran S. Anap... more Alex Ruane, Sonali McDermid, Nicholas Hudson, Cynthia Rosenzweig, L. R. Ahuja, Saseendran S. Anapalli, Jakarat Anothai, Senthold Asseng, Dumont Benjamin, Federico Bert, Patrick Bertuzzi, Virendra S. Bhatia, Marco Bindi, Ian Broad, Davide Cammarano, Ramiro Carretero, Uran Chung, Giacomo De Sanctis, Thanda Dhliwayo, Frank Ewert, Roberto Ferrise, Thomas Gaiser, Guillermo Garcia, Sika Gbegbelegbe, Vellingiri Geethalakshmi, Edward Gerardeaux, Richard Goldberg, Brian Grant, Edgardo Guevara, Holger Hoffmann, Huanping Huang, Flavio Barbosa Justino, Asha S. Karunaratne, Ann-Kristin Koehler, Soora Naresh Kumar, Arunachalam Lakshmanan, Xiaomao Lin, Qunying Luo, Graciela Magrin, Yuji Masutomi, Theodoros Mavromatis, Greg McLean, Santiago Meira, Monoranjan Mohanty, Marco Moriondo, Lamyaa Negm, Francesca Orlando, Isik Ozturk, Zhiming Qi, Johanna Ramarohetra, Helene Raynal, Gabriel Rodriguez, Vaishali Sharda, Lu Shuo, Ward Smith, Afshin Soltani, K.Srinivas, Dillip Kumar Swain, Fulu Tao, Kindie Tesf...
Recognizing that climate change will affect agricultural systems both through mean changes and th... more Recognizing that climate change will affect agricultural systems both through mean changes and through shifts in climate variability and associated extreme events, we present preliminary analyses of climate impacts from a network of 1137 crop modeling sites contributed to the AgMIP Coordinated Climate-Crop Modeling Project (C3MP). At each site sensitivity tests were run according to a common protocol, which enables the fitting of crop model emulators across a range of carbon dioxide, temperature, and water (CTW) changes. C3MP can elucidate several aspects of these changes and quantify crop responses across a wide diversity of farming systems. Here we test the hypothesis that climate change and variability interact in three main ways. First, mean climate changes can affect yields across an entire time period. Second, extreme events (when they do occur) may be more sensitive to climate changes than a year with normal climate. Third, mean climate changes can alter the likelihood of cli...
International Journal of Climatology, 2020
Gridded climate datasets are among the most used datasets in the study of weather and climate. Gi... more Gridded climate datasets are among the most used datasets in the study of weather and climate. Given the large range of such products currently available, investigators must consider their strengths and weaknesses. This research evaluated the comparative performance of two reanalysis datasets (ERA‐Interim, and Agri4Cast [e.g. MARS‐STAT]) and one reprocessing dataset (E‐OBS) in replicating selected spatiotemporal characteristics of precipitation and drought at 20 wine production regions in Greece during 1981–2012. The results highlighted the abilities of E‐OBS and Agri4Cast, whose performance varied with season and the specific rainfall characteristic in question. The former product: (1) reproduced better the annual decreasing trends in spring, summer, and autumn, (2) captured a larger portion of the observed monthly variability in spring and summer, associated better and showed the lowest errors with observations, and (3) computed better or equal to Agri4Cast different skill scores applied on the daily time series, replicated better the probabilities of wet and dry days and equally well with Agri4Cast the extreme precipitation indices. Agri4Cast replicated better the monthly cycle of precipitation (underestimating though the station averages) and the increasing trend from SE to NW, on spatial basis. With regards to drought monitoring, frequency and detection of very and extremely wet and dry spells, SPI was superior to SC‐PDSI (the self‐calibrated version of Palmer's index), particularly when E‐OBS data was used. Agri4Cast and E‐OBS are the most appropriate products for use in climate/atmospheric‐related research over Greece.
OENO One, 2020
Aim: This research aimed to: (1) investigate the relationships between harvest dates and berry co... more Aim: This research aimed to: (1) investigate the relationships between harvest dates and berry composition with air temperature during important periods during the growing season, across a range of indigenous and international winegrape varieties grown in wine regions over the majority of Greece; (2) calculate growing degree-days (GDD) from 1st of April until the harvest date of each variety and group the winegrape varieties according to their heat requirements; and (3) predict future harvest dates based upon these heat requirements under different representative emission pathways (i.e., RCP4.5 and RCP8.5) and future time periods (2041-2065 and 2071-2095) using an ensemble projection dataset.Methods and results: The analysis of heat requirements based on GDD from 1st of April to harvest date identified consistent maturity groups of the varieties studied, especially for indigenous Greek varieties. Trend analysis using the basic linear regression model showed that harvest dates have s...
Scientia Horticulturae, 2021
Abstract Extreme rainfall events pose a threating factor for the income of growers, processing in... more Abstract Extreme rainfall events pose a threating factor for the income of growers, processing industry and communities; however little is known on damages caused on peach trees. The pattern of historical trends in precipitation and the Standardized Precipitation Index (SPI) characteristics during the summer months were studied in Naoussa, Northern Greece. Damages from naturally occurring summer rainfalls were recorded in a peach and nectarine cultivar evaluation orchard and effects from a simulated rainfall experiment using prolonged (100 mm in 3 days) and intense (100 mm in 1 day) rainfall treatments were monitored on peach cv. ‘Elegant Lady’ trees. Results showed that during the summer months of 1967–2019, there was no significant effect in the precipitation totals and the Standardized Precipitation Index (SPI) characteristics, although an increase in the frequency of wet spells is noticeable in the last three years. Fruit drop and symptoms of skin streaking, bronzing, and collapse in skin tissue of peach and nectarine cultivars close to maturity initiated during and continued after the end of severe and extreme wet spells of three or more consecutive rainy days in a summer month in 2017, 2018 (total ca. 100 mm) and 2019 (total 54 mm) were recorded. The type of skin damages differed among peach and nectarine cultivars. Greater extent of damages was documented in the peach cvs ‘Kevina®’, ‘Maura®’ and ‘Royal Time®’ and fewer damages in ‘Red Haven’, and ‘Sweet Scarlet’. The rainfall simulation experiment showed that only the prolonged, and not the intense treatment, caused fruit drop starting two days after the treatment initiation and lasted three days after the end, while streaking symptoms developed mostly in fruit from the prolonged rainfall treatment. In conclusion, the consecutive wet days rather than the total rainfall caused fruit drop and skin damages in peach and nectarine fruits close to harvest, while cultivars differed in the type of damage developing. Insurance programs need to be readdressed, incorporating rainfall frequency rather than total monthly rainfall as indicators of yield, as well as including the symptoms of fruit drop, skin streaking, bronzing and collapse as damages rather than cracking in peach and nectarine.
We use the CERES family of crop models to assess the effect of different spatial scales of climat... more We use the CERES family of crop models to assess the effect of different spatial scales of climate change scenarios on the simulated yield changes of maize (Zea mays L.), winter wheat (Triticum aestivum L.), and rice (Oryza sativa L.) in the Southeastern United States. The climate change scenarios were produced with the control and doubled CO2 runs of a high resolution regional climate model and a coarse resolution general circulation model, which provided the initial and lateral boundary conditions for the regional model. When considering the effect of climate change only at the individual state level, maize yields decreased in all states for both scenarios (─5 to ─29%), but the differences in yields between the two scenarios were generally significant, the coarse scale showing the larger decreases. Winter wheat yield decreases (─27 to ─48%) were larger than those for maize but the differences in yields produced by the two climate change scenarios were insignificant in most states....
Theoretical and Applied Climatology, 2014
Notwithstanding technological developments, agricultural production is still affected by uncontro... more Notwithstanding technological developments, agricultural production is still affected by uncontrollable factors, such weather and climate. Within this context, the present study aims at exploring the relative influence of growing season climate on the yields of major cereals (hard and soft wheat, maize, and barley) on a regional scale in Greece. To this end, crop-climate relationships and the impacts of climate trends over the period 1978-2005 were explored using linear regression and change point analysis (CPA). Climate data used include maximum (Tx) and minimum temperature (Tn), diurnal temperature range (Tr), precipitation (Prec), and solar radiation (Rad). Temperature effects were the most substantial. Yields reduced by 1.8-7.1 %/°C with increasing Tx and by 1.4-6.1 %/°C with decreasing Tr. The warming trends of Tn caused bilateral yield effects (from −3.7 to 8.4 %/°C). The fewer significantly increasing Rad and decreasing Prec anomalies were associated with larger yield decreases (within the range of 2.2 % MJ/m 2 /day (for maize) to 4.9 % MJ/m 2 /day (for hard wheat)) and smaller yield increases (from 0.04 to 1.4 %/mm per decade), respectively. Wheat and barley-the most vulnerable cereals-were most affected by the trends of extreme temperatures and least by Tr. On the contrary, solar radiation has proven to be the least affecting climate variable on all cereals. Despite the similarity in the direction of crop responses with both analyses, yield changes were much more substantial in the case of CPA analysis. In conclusion, regional climate change has affected Greek cereal productivity, in a few, but important for cereal production, regions. The results of this study are expected to be valuable in anticipating the effects of weather/climate on other warm regions worldwide, where the upper temperature limit for some cereals and further changes in climate may push them past suitability for their cultivation.
Handbook of Climate Change and Agroecosystems, 2015
International Journal of Climatology, 2013
Climate characteristics and relationships with indigenous varieties in Greece are examined to bet... more Climate characteristics and relationships with indigenous varieties in Greece are examined to better understand how these varieties perform in their native climate and assess the impact regional climate change has on the Greek wine industry. Thus, harvest dates (ΔH) for eight indigenous varieties and regions, along with climate data, were gathered and systematically explored using linear regression models and principal component analysis for three ‘effective’ growing season time period definitions (calendar year, growing season and ripening period). The eight study regions had marked differences in their general climatic characteristics, mainly between mainland and island areas. ΔH response was not particularly sensitive to time period definition. In five out of eight regions, a systematic shift of ΔH was identified (earlier harvest), mainly driven by changes in maximum and minimum temperatures. Significant trends in climate parameters and viticulture–climate relationships were more evident for island regions when compared to mainland locations. Moreover, areas with late ripening varieties were shown to be less sensitive to climate changes. Only in one region harvest was delayed, possibly due to non‐climate factors. The identification of up‐to‐date climate and grapevine phenology relationships could be an important step for broader and more confident future assessments of climate suitability for viticulture and climate change impacts in Greece, and provide insights into how lesser known varieties might perform in other regions.
Climate Research, 2008
Lack of data on site-specific daily solar radiation (R g) is a significant impediment for most cr... more Lack of data on site-specific daily solar radiation (R g) is a significant impediment for most crop modeling applications. For this reason, 5 methods for estimating R g were tested: the Ångström-Prescott equation (AP), the Supit-van Kappel formula (SK) and 3 temperature-based methods: Campbell-Donatelli model, Hargreaves equation, and piecewise multiple linear regressions with a breakpoint (PLR). To overcome the lack of long and continuous time series of R g measurements at multiple sites, satellite-derived R g from the HelioClim-1 database were tested against observations from 2 stations, and then interpolated for 12 additional stations. When sunshine duration data were available, the AP equation was best, because it (1) produced intercepts and slopes closest to zero and unity, respectively and (2) had the lowest relative RMSE (9 to 18.6%). When cloud cover observations and data on maximum and minimum temperatures were available, the SK equation was equally effective as AP in most assessment metrics. When the only data for a site were daily maximum and minimum temperatures, the PLR approach with a breakpoint, which reflects the value at which the response of daily R g changes as a function of the extraterrestrial solar radiation R A and the diurnal temperature range, performed best. The mean relative RMSE of the PLR approach was < 3.7% higher than that of AP. The SK equation provided the most suitable simulation of measured R g for the CERES-Wheat crop model, while among the temperature-based methods PLR produced the smallest yield errors. Future validation efforts should explore the validity of the PLR model in other regions and under regimes with greater availability of R g data
Climate Research, 2005
Lack of site-specific global solar radiation (GSR) data is a significant impediment for most crop... more Lack of site-specific global solar radiation (GSR) data is a significant impediment for most crop model applications. First, several empirical methods for estimating GSR from observed maximum and minimum temperature were evaluated using data from urban (National Climatic Data Center [NCDC] data set) and rural (Florida Automated Weather Network [FAWN] data set) sites in Florida. Next, the spatial structure of empirical model parameters was investigated and the possibility of employing spatially interpolated coefficients developed at urban or rural sites to predict solar radiation at rural locations, where most crops are grown and often crop modeling is required to address various issues, was assessed. Finally, the effects of observed and estimated GSR on simulated potential yield and evapotranspiration with CROPGRO-Peanut and CERES-Maize models at 6 crop-location combinations were evaluated. The model developed by Donatelli and Bellocchi (DB) achieved the most accurate estimations of GSR across Florida. The quality of those predictions varied with environment setting (urban-rural) and latitude. RMSE (root mean square error) between observed and fitted daily GSR were in the range of 3.1-4.1 and 3.2-4.9 MJ m-2 d-1 for FAWN and NCDC evaluation subsets , respectively. Radiation for FAWN sites was efficiently estimated by the coefficients interpolated from rural sites but was substantially overestimated by 17.6%, on monthly basis, when urban sites supplied the model empirical parameters. NCDC sites were site specific and suitable sources of solar radiation at urban environments only. Input of estimated with the DB model GSR into a crop model would be a realistic option at sites where only temperature and precipitation are available.