Volume 24 (2021): Issue s1 (May 2021)
Special Issue

The purpose of this study is to evaluate the impact of climate uncertainties on maize irrigation requirements, grown on a Vertisol soil, Sofia’s field, Bulgaria. Through the validated WinIsareg model, four irrigation scheduling alternatives are simulated for the years of “very high“, “high“ and “average“ irrigation demands of past (1952–1984) and present (1970–2004) climate. Adaptation of irrigation scheduling to the present climate conditions during the “very dry“ years (P_I ≤12%) consists of an extension of the irrigation season by 15–20 days and a need of additional irrigation relative to alternative 1 and two irrigation events at alternatives 2 and 3. During the past climate alternatives 2 and 3 led to savings of 30 mm of water, while up to the current climate conditions the three irrigations alternatives should provide 360 mm of irrigation water. To obtain maximum yields in “dry“ (P_I = 12–30%) years, irrigation season should end by 05/09, as in the present climate, irrigation season has shifted about a week earlier for the three alternatives. In the “average“ (P_I = 30–60%) years the adaptation consist in accurately determination of the last allowed date for irrigation.

Nowadays, the development of irrigation is increasingly recognized as a necessary factor in agriculture, primarily because of global warming. Depending on the field conditions, the most commonly used method is sprinkler irrigation. The spray uniformity of sprinklers installed on the field irrigation equipment can be characterized by the Christiansen-uniformity coefficient (CUc%) and the distribution uniformity coefficient (DU%). Our investigations were carried out on the lateral moving irrigation equipment of University of Debrecen, Institutes for Agricultural Research and Educational Farm and Nyírbátor’s company in Hungary in 2019. Variable rate irrigation (VRI) is used in Nyírbátor. In contrast, the VRI has given positive results, making an irrigation equipment with the VRI a safer and more uniform method than a conventional linear irrigation equipment.

The active biomass of cultivated plants and average yield decreases as a result of biotic and abiotic stress effect. The extent of the reduction can be quantified on the basis of remotely sensed data. The aim of this research is to evaluate the suitability of Landsat 8 data for a wheat yield estimation. We processed Landsat 8 recordings for the period 2013–2019 and generated NDVI data. Time series NDVI data were calibrated and validated with observed wheat yield averages. The agricultural plots around Karcag, Hungary, were our research area. The relation between Landsat NDVI data and yield was strongest and highest in the total biomass period (R² = 0.53–0.54) and the estimation error based on RMSE is between 0.48–0.7 t.ha⁻¹.

Water is the most essential substance regarding the physiological processes of any living system. Agricultural activities and global food security are highly influenced by water availability. The value of water and water resources already exceeds that of energy sources today. The water-related concepts are very diverse in agricultural relations. The aim of this paper was to revive some terms related to water and discuss their importance in soil-plant systems. In this paper, eight phrases were selected paying attention to the importance of water management, namely soil water management, soil moisture range for workability, rain stress, water logging, water shortage, irrigation, water intake and water loss, avoiding water loss and reply to climate change phenomena. Findings of water management research point to a relationship between soil quality and improvement of water intake capacity, parallel with climate stress mitigation.

Under the increase of the concern for food security in the world, mainly caused by water resources shortages, the forecast and determination of crop yield at regional scale has been considered as a strategic topic. This study has been conducted to assess the possible impacts of the climate change on cereal crops productivity and irrigation requirement for two main producing regions of Georgia, according to the current crop pattern, and for the 2050s periods. With this aim, water-driven FAO-AquaCrop model has been used. Furthermore, ongoing and forecasted changes, up to the end of the century, in agro-climatic zones relevant for cereals production have been assessed. The climate change data was generated for RCP4.5 scenario through the global circulation model ECHAM4.1, dynamically downscaled on the region via regional climate model (RegCM4.1). Results show overall increase in cereal crop yields, but also enhancement in water shortages even considering optimum management practices under rainfed conditions. Based on the results obtained, recommendations have been developed for adaptation measures to the climate change for the Georgia Agriculture sector.

Since the beginning of the 21^st century, studies of glaciers in Georgia have become more important, because the degradation of glaciers causes an increase in the intensity and frequency of natural disasters of a glacial and hydrological nature, an increase in water levels in the Black Sea, and a changes in river water regime. Studying the current state of the ice sheet in Georgia is an important national economic task, and to obtainobtaining a scientifically sound answer on modern conditions of the glaciers, due to the impact of current climate change is an urgent task. To solve this task, high-resolution satellite remote sensing (SRS) is used. The r. Rioni basin (West Georgia) is one of the most important glacier basins in Georgia, where the powerful glaciers are spread and their change is of great interest. In this work there are presented the results of the study of r. Rioni glasiers glaciers degradation due to the influence of current climate change including the expected time of their full melting.

Rainfall erosivity factor (R) of the USLE model is one of the most popular indicators of areas potentially susceptible to soil erosion. Its value is influenced by the number and intensity of extreme rainfall events. Since the regional climate models expect that the intensity of heavy rainfall events will increase in the future, the currently used R-factor values are expected to change as well. This study investigates possible changes in the values of R-factor due to climate change in the Myjava region in Slovakia that is severely affected by soil erosion. Two rain gauge stations with high-resolution 1-minute data were used to build a multiple linear regression model (r² = 0.98) between monthly EI₃₀ values and other monthly rainfall characteristics derived from low-resolution daily data. The model was used to estimate at-site R-values in 13 additional rain gauge stations homogeneously dispersed over the whole region for four periods (1981–2010, 2011–2040, 2041–2070, 2071–2100). The at-site estimates were used to create R-factor maps using a geostatistical approach. The results showed that the mean R-factor values in the region might change from 429 to as much as 520 MJ.mm.ha⁻¹.h⁻¹.yr⁻¹ in the second half of the 21^st century representing a 20.5% increase.

The long-term runoff variability is identified to consist of the selected large rivers with long-term data series in the Danube River Basin. The rivers were selected in different regions of the Danube River Basin and have a large basin area (Danube: Bratislava gauge with 131,338 km²; Tisza: Senta with 141,715 km²; and Sava: Sremska Mitrovica with 87,966 km²). We worked with the station Danube: Reni in the delta as well. A spectral analysis was used to identify the long-term variability of three different types of time series: (1) Average annual discharge time series, (2) Minimum annual discharge time series and (3) Maximum annual discharge time series. The results of the study can be used in a long-term forecast of the runoff regime in the future.

High air temperatures and low amount of precipitation occur more and more frequently in Slovakia. The aim of this work is to evaluate the temperature conditions and total precipitation during the period 2005–2019 and to compare it with the 50-year climatic normal 1951–2000. Also, there was calculated the probability of summer days, tropical days, super-tropical days, frost days and ice days occurrence. Annual temperature is higher by 0.9 °C (1.1 °C during vegetation period) than normal. Rainfall, especially in the last 5 years, has a decreasing character (-75 mm.year⁻¹) with frequent fluctuations. New phenomena – super-tropical days has occurrence of up to 20% between July and August. This study provides information based on which adaptation measures to the climate change need to be taken.

We live in the times of climate change when global temperatures are constantly rising. The impacts of climate change will also be felt in agriculture in Slovakia: increased productivity and yields in colder areas, reduced production in warmer areas due to temperature stress, risk of erosion as a result of more extreme weather conditions (stronger winds, more intense precipitation), the occurrence of new pests etc. Hence, we should be prepared for adaptation measures that would help mitigate it. The aim of this paper is to present the impacts of climate change on agriculture and land, and to offer adaptation measures, and show the prognosis of the climate indicator Ts >10 °C from now until 2100.

Over the past few decades, food production has been sufficient. However, climate change has already affected crop yields around the world. With climate change and population growth, threats to future food production come. Among the solutions to this crisis, breeding is deemed one of the most effective ways. However, traditional phenotyping in breeding is time-consuming as it requires thousands and thousands of individuals. Mechanisms and structures of stress tolerance have a great variability. Today, bigger emphasis is placed on the selection of crops based on genotype information and this still requires phenotypic data. Their use is limited by insufficient phenotypic data, including the information on stress photosynthetic responses. The latest research seeks to bring rapid, non-destructive imaging and sensing technology to agriculture, in order to greatly accelerate the in-field measurements of phenotypes and increase the phenotypic data. This paper presents a review of the imaging and sensing technologies for the field phenotyping to describe its development in the last few years.

Increasing population has led to the increasing demand for food, raw materials, and energy. Continuing land use changes, intensification of its exploitation, deforestation, fossil fuel combustion, and related carbon dioxide production have been contributing to change of water and energy balance of the globe, thus changing conditions for life. Other reasons for changing conditions on the Earth are natural changes in interactions between the Earth and outer space. Actual climate change is a part of other global changes resulting in both natural and anthropogenic changes. It is mostly felt as a change of global temperature and increase of precipitation intensities and totals. Flood periods are followed by long periods without precipitations. Increasing population as well as increasing consumption of resources lead to the increasing imbalance between our planet production and consumption. To preserve good conditions for population of the Earth, it is necessary to decrease consumption of energy, raw materials, and food to reach equilibrium between Earth´s ecosystem production and consumption of the ecosystem products.

Natural climate fluctuation, as well as expected climate change, brings additional water regimes in the flow of a number of serious issues and uncertainties. The upper parts of the river basins are suitable for studying the effect of potential climate change or increased air temperature on drainage conditions in the basin. The Váh River is the biggest left-side Danube River tributary and the second biggest river in Slovakia. Gauging station Váh – Liptovský Mikuláš is the final profile above the water reservoir Liptovská Mara, one of the largest reservoirs in Slovakia. The contribution deals with the trend analysis of the extreme flows regime and the waves volume belongs to the annual maximum flow at gauging station Váh – Liptovský Mikuláš in a selected time period (1931–2015). Consequently, the trend analyses of precipitation depth and air temperature have been made at three selected meteorological stations located in the upper part of the Váh River basin. We have used the Mann-Kendall nonparametric test, which is one of the most widely used nonparametric tests to detect significant trends in a time series.

Total climate changes are a combination of climate changes due to human activities and climate changes of natural origin. Further development of climate change can be predicted, if we know the future development of GHG emission into the atmosphere and other human interventions with the world climate system. The future development in natural climate changes cannot be reliably predicted. It is very probable that climate change caused by humans will be much more significant than the natural climate changes, already from 2020. It is almost certain that the concentration of GHG in the Earth’s atmosphere will rise further for at least 100 years. The climate change scenarios can be prepared, according to the outputs of General Earth’s atmospheric circulation physical models (GCM). Adapting and mitigation measures projection to utilise or slow down the impact of the expected climate change are the next steps of the climate change issues solving.

Drought has recently become an important topic in Europe but also in Slovakia. Observed results from various studies suggest that this drought phenomenon has a serious impact on hydrology, agriculture and social and economic sectors. The first part of the paper was devoted to the study of literature from the field of existing drought indices, which serve to identify all types of drought such as meteorological, agricultural and socio-economic drought. The second part of the paper dealt with selected scientific studies on drought assessment and the use of drought indices in Central Europe and Slovakia.

Biochar application into soil has potential as a means for reducing soil greenhouse gas emissions and climate mitigation strategy. In this study, we evaluated the impact of two doses of biochar (10 and 20 t.ha⁻¹) applied in 2014, combined with three fertilization levels (N0, N1, N2) on carbon dioxide (CO₂) in field conditions during the growing season (April – October) in 2018. The field site is located in the Nitra region of Slovakia – Malanta. The soil in the field was classified as a silt loam Haplic Luvisol. There was not found any statistically significant (P <0.05) decreasing effect of biochar with or without N-fertilizer after four years of its application on average daily and cumulative CO₂ emissions, while the CO₂ emissions increased with additional N-fertilizer. Biochar decreased (insignificantly) the daily and cumulative CO₂ emissions only in the treatments without N-fertilization and in the treatment fertilized with higher level of biochar application (20 t.ha⁻¹) and N-fertilizer (80 kg.N.ha⁻¹). According to these results it can be concluded that the biochar applied to soil is not able to reduce CO₂ emissions after four years of its application when it is combined with usual agriculture practices which include N-fertilization.

Drought impacts are significant and widespread on a year-to-year basis, affecting many economic sectors and people at any time. Definitions of drought are clustered into four types: meteorological, hydrologic, agricultural, and socio-economic. In our paper we focus on the comparison of meteorological drought (defined as a period with no precipitation) and agricultural drought (determined as the value below the amount of water storage in the soil profile accessible to plants). The meteorological stations of the Department of Biometeorology and Hydrology of the Slovak University of Agriculture (SUA) in the Nitra River Basin (Slovakia) – Bystričany, Solčany and Palárikovo – were used for the research. Soil moisture was recorded at horizons 0–0.15 m and 0.15–0.30 m. The occurrence of meteorological as well as agricultural drought in the Bystričany locality has changed quite significantly – not only in the summer months but also in the autumn and often in the spring. Meteorological drought in the Solčany locality occurs regularly almost throughout the whole year. Agricultural drought is becoming more regular in the last monitored years. In Palárikovo (the southernmost locality) the occurrence of meteorological drought is regular and even occurs in the spring and autumn months. Agricultural drought also occurs regularly. To increase agricultural production, it is necessary to focus not only on meteorological drought, but also on agricultural drought and soil characteristics in individual localities. We analysed the drought to the depth of 0.30 m, but in the deeper layers there may be enough moisture for the crops´ root systems.