Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat ...conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981–2010. Observed trends (1961–2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.
The climate clearly determines the characteristics of agriculture in terms of favourable conditions for the development of plants and animals. Climate change has a major impact on agriculture, and we ...need at least its analysis for past decades for effective adaptation. The annual scale of meteorological variables is quite rough, much more information is obtained from the monthly scale, for example when using bioclimatic indices and diagrams. Using Griffiths-Taylor diagrams, where each point shows the average monthly value of temperature and relative humidity or precipitation, we showed the change of 30-year averages (1961 to 2020) for six climate stations. Climate change can be seen from the shape of the diagram, an increase in average monthly air temperatures, a decrease in average relative humidity and changed precipitation patterns are visible. With the plot of favourable conditions for a certain plant / animal species, the diagram acquires ecological value. We have shown changes in the conditions for the development of the fruit fly (Ceratitis capitata (Wiedemann, 1824)) and the growth of sweet potatoes (Ipomoea batata L.). For the fruit fly, conditions improved due to higher temperatures, especially in colder locations. In Murska Sobota, which has the only suitable conditions for the growth of sweet potatoes, the period with favourable conditions is extended, in the last two periods in July and August, ideal conditions also appear. In further research, we recommend an analysis of weather-extreme years, which provides additional information on the variability of the conditions.
Considering that the relationships between agrometeorological drought indices and the impact of agricultural drought in Slovenia are not yet well understood, the aim of this study was to make an ...indicative evaluation of the success of selected drought indices, addressing topsoil layer and vegetation condition, in detecting drought in agriculture. In this study, the performance of two established drought indices—the SPEI (standardised precipitation evapotranspiration index) and the VHI (vegetation health index)—was evaluated with respect to yield values calculated with the LINGRA-N model, specifically, the ratio between actual and potential transpiration, also known as drought factor (TRANRF), actual root zone water content (SMACT), leaf area index (LAI), reserve dry weight (WRE), and root dry weight (WRT). The two grassland species selected for analysis were Dactylis glomerata L. (dg) and Lolium perenne L. (lp). For the period 2002–2020 or 2015–2020, three farm sites in Slovenia were considered for evaluation, with two farms at a higher altitude site and one farm at a lower altitude site in the Alpine region. Evaluation of the yield data with the drought indices showed that the r2 values of the linear regression for the selected years with the highest drought impacts (2003, 2013, and 2017) were highest between the two SPEI indices (SPEI-2, SPEI-3) and the model variables TRANRF, SMACT, and WRT, with r2 higher than 0.5 and statistically significant for the lower situated farm in 2013. For 2003 and 2017, the r2 values were less significant as well as for the model variable WRE for all three years selected for analysis (2003, 2013, and 2017).
Calibration and validation of the LINGRA-N model were performed using herbage dry matter (DM) yield data from field studies conducted at three locations in Slovenia. Calibration was done by ...minimising root mean square error (RMSE) and validation by using RMSE and Willmott’s index of agreement (dw). Calibration of LINGRA-N was not successful for the experiment conducted on permanent grassland in Ljubljana in the period 1974-1993 (RMSE% = 14%, dw = 0.37). Better results were obtained for grass monocultures in Jablje (J) and Rakičan (R) in the period 1998– 2013, with the best fit for cocksfoot (Dactylis glomerata L.; RMSE% = 12%, dw = 0.84). Fifty-year simulations were performed for cocksfoot (J-DG) and timothy grass (Phleum pratense L.) in Jablje (J-PP) and perennial ryegrass (Lolium perenne L.) in Jablje (J-LP) and Rakičan. Outliers with very low simulated herbage DM yield were detected only in the second half of the study period and were associated with drought and/or high maximum air temperatures. A time series analysis of annual potential yield values showed a statistically significant (P=0.05) negative trend for J-LP (–24 kg DM ha–1year–1) and J-PP (–29 kg DM ha–1year–1). A change in the variability of the reduction factor for crop growth due to drought was already noticeable.
Climate changes and the associated higher frequency of heat waves in Middle-European countries will aggravate occupational heat stress experienced by Slovenian workers. Appropriate behavioral ...adaptations are important coping strategies and it is pertinent to establish if knowledge among advisers and workers is sufficient and identify the symptoms experienced by workers. Therefore a survey including 230 farmers and 86 agricultural advisers was completed. Thermal comfort ranged from hot to extremely hot for 85 ± 5 % of farmers working outside and heat stress had a negative impact on well-being (74 ± 6 %), productivity (68 ± 6 %) and concentration (34 ± 6 %). Reported symptoms were excessive sweating (84 ± 5 %), thirst (81 ± 5 %), and tiredness (59 ± 6 %). Women had a higher prevalence of headache (64 ± 10 %) compared to males (47 ± 8 %), higher frequency of fatigue (69 ± 10 vs 56 ± 8 %), and incidents with nausea or vomiting (19 ± 8 vs 9 ± 5 %). 81 ± 4 % of the responders reported that more time is required to complete tasks when the weather is hot. Nevertheless, 61 ± 6 % of farmers have never been informed of the impacts of heat stress and 29 ± 10 % of the agricultural advisers does not include this information in their guidance. This emphasizes the need for increased information and implementation of feasible solutions to mitigate the negative impact of heat stress on workers in the agricultural sector.
Changing patterns of heat waves are part of the global warming effect and the importance of changes is reinforced by their negative impact on society. Firstly, heat waves were analyzed in Brnik ...(Slovenia) and Larisa (Greece) in the period 1981⁻2017 to reflect the environment which workers are exposed to. Secondly, outdoor workers (70 from Greece, 216 from Slovenia) provided a self-assessment of heat stress. The heat wave timeline is presented as an effective way of illustrating long-term changes in heat waves' characteristics for various stakeholders. In both countries, workers assessed as significant the heat stress impact on productivity (Greece 69%, Slovenia 71%;
> 0.05), and in Slovenia also on well-being (74%;
< 0.01). The main experienced symptoms and diseases were thirst (Greece 70%, Slovenia 82%;
= 0.03), excessive sweating (67%, 85%;
= 0.01), exhaustion (51%, 62%;
> 0.05) and headache (44%, 53%;
> 0.05). The most common way to reduce heat stress was drinking more water (Greece 64%, Slovenia 82%;
= 0.001). Among the informed workers, the prevalent source of information was discussions. Therefore, educational campaigns are recommended, together with the testing of the efficiency of mitigation measures that will be proposed on the Heat-Shield project portal.
Workers in agriculture are regularly exposed to heat stress during summer, which can affect reduced labour productivity and income losses. Air temperatures in Slovenia have been rising in recent ...decades, and climate change projections show that this trend will continue along with an increase in the number of days with heat stress risk. Changes in the number of heat waves in central and south-western Slovenia for the period 1961–2017 were analysed as well as the risk of the heat stress for workers during heat waves in the year 2017. The heat wave occurs if the temperature threshold for the average daily temperature is reached or exceeded on at least three consecutive days, with the threshold for the mild continental climate (Ljubljana) 24 °C and the mild Submediterranean climate (Bilje) 25 °C. The WBGT (Wet Bulb Globe Temperature) index, assessing the risk of heat stress, was calculated from relative humidity and air temperatures. At both locations, the number of days in heat waves increased as well as their intensity, average daily air temperatures were significantly higher than in the first half of the considered period. The time span, in which the heat waves occur, also extended, as until 1990 they did not appear in early June and late August, as in recent years. The calculated values of the WBGT show that for most days in the heat waves in 2017 in Ljubljana and Bilje, the WBGT 23 °C threshold was exceeded practically all day, which shows a high level of heat stress risk for physically intense work. In the case of exceeded WBGT reference values, employers or farmers themselves should take actions to reduce the risk of heat stress.
In the study the previously calibrated LINGRA-N model was used for a long term simulation (1964–2013) of the herbage dry matter yield (GRASS) and growth analysis of Cock’s foot (Dactylis glomerata ...L.) in Jablje. Changes in the yearly GRASS variability are reflected in the appearance of outliers in the second half of the study period. The biggest reductions in GRASS are seen in the years 1992, 1993 and 2003. These are the driest years according to meteorological variables (high maximum and minimum air temp eratures, low precipitation) and also according to the simulations, with the lowest reduction factor for crop growth due to drought. The potential yield (YIELD) is not linearly dependent on meteorological variables. Some growth compone nts were compared on a daily basis in a dry year (1993) and an average year (1994). In 1993, for instance, 53 % of photosynth etically active radiation was intercepted, against 75 % in 1994. Seasonal development of the actual soil moisture content was linked to the development of the leaf area index and consequently to the mass of green leaves, to the roots mass, to the mass of dead leaves and to GRASS. The results highlight the need for further research, on field and with simulations. As re gards the latter, we have to keep in mind that they inevitably involve various uncertainties.
▶ Main effects of WOFOST parameters to total output variance under different growing conditions. ▶ Bayesian calibration reduced uncertainty of parameters in dynamic crop model. ▶ Posterior ...distribution of model parameters are site-specific. ▶ Significant differences can occur between linear and nonlinear phenological methods. ▶ Wang–Engel model most accurately simulates phenological development of maize.
The main objective of our study was to use Bayesian methods to quantify the uncertainties related to phenological development of maize (
Zea mays L.) under various climate conditions. For this purpose, five different phenological methods were implemented in the dynamic crop growth model, which was subsequently optimized, using the data acquired at three different locations in Slovenia. The sensitivity analysis of the crop model was performed in order to find the set of most influential physiological parameters. Subsequent Bayesian model comparison was used in order to quantify the impact of phenological method selection on the final maize yield. The results revealed the importance of using an appropriate phenological method in order to correctly estimate the duration of the growing season and yield, when used within dynamic crop model. The limitations of the phenological methods used in this study are discussed. The selection of phenological method itself did not have a significant influence on the yield estimation, except in years with high temperatures and limiting water conditions. This raises the concern that inaccurate simulation of phenological development may increase the uncertainties of impact assessment on crop yield where crop models are fed with future climate projections.
Climate factors that are proposed to determine agriculturally less favoured areas (LFA) in Slovenia were analyzed for the period 1981–2010. Following the instructions of European Commission prepared ...by Joint Research Centre (JRC) 30-years averages of low air temperatures criteria (the vegetation period duration and sums of effective air temperatures) and aridity criteria (aridity index AI) have to be calculated. Calculations were additionally done using Slovenian Environment Agency (ARSO) method, which is slightly different when determining temperature thresholds. Only hilly areas are below the LFA low air temperatures threshold with the lowest located meteorological station in Rateče. According to aridity criteria no area in Slovenia is below the threshold, so meteorological water balance was also examined. Average water balance in the period 1981–2010 was in most of locations lower than in the period 1971–2000. Climate change impacts are already expressed as trend presence in time series of studied variables, so it is recommended to calculate trends and take them into account or to perform regular iterations of calculations.
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