Climate change is affecting all sectors of human activities worldwide, including crop production. The aim of the paper was to evaluate the average daily air temperatures measured at one hundred meteorological stations across Slovakia in 1961–2010 and calculate the maximum length of the vegetation period for Solanum lycopersicum L., Brassica oleracea L. var. capitata and Daucus carota L. Future trends predictions of the temporal and spatial development across the duration of the vegetation period in Slovakia were elaborated for decades 2011–2020, 2041–2050, 2071–2080 and 2091–2100. Our results show that there was an earlier start to the vegetation period in spring and a later termination in autumn for past 30 years. There is a predicted trend of prolongation of the maximum duration of the vegetation period up to 20 days (Solanum lycopersicum L., Brassica oleracea L. var. capitata) and 15 days (Daucus carota L.) in comparison with the refence decade 2001–2010. The maximum vegetation period duration will extend from the south of Slovakia towards the north of the country. The predicted potential increase in crop vegetation periods will be limited by other constraints such as the availability of arable land and soil water availability.

The purpose of the paper was to show cognition from the theory of climate change. The map outputs of these changes offer the climate data from basic elements and characteristics of the energy balance in terms of the current state as well as the trends and assumptions of their future changes in Slovakia. For these agroclimatic analyses, 100 climatic stations in Slovakia spread out to cover all agricultural regions, up to 800 m above sea level, have been selected. Our analyses are related to the period of years 1961-2010, when measurements and observations were the most homogeneous. The future trends and map outputs of future climate change were determined with the mathematic-statistical methods to the 2035, 2050, 2075-and 2100-year horizons. This study presents the impact of the climate change on the temperature conditions in Slovakia. The temperature changes (average, maximum and minimum temperature) were analysed with forecasts up to year 2100. The forecasts for the 2100-year horizon indicate increasing of the average annual temperature on average by about 2.0°C, maximum temperature on average by about 2.0°C and minimum temperature on average by about 2.5-3°C in comparison to the present.

Recent findings of changing climate, water scarcity, soil degradation, and greenhouse gas emissions have brought major challenges to sustainable agriculture worldwide. Biochar application to soil proves to be a suitable solution to these problems. Although the literature presents the pros and cons of biochar application, very little information is available on the impact of repeated application. In this study, we evaluate and discuss the effects of initial and reapplied biochar (both in rates of 0, 10, and 20 t ha−1) combined with N fertilization (at doses of 0, 40, and 80 kg ha−1) on soil properties and N2O emission from Haplic Luvisol in the temperate climate zone (Slovakia). Results showed that biochar generally improved the soil properties such as soil pH(KCl) (p ≤ 0.05; from acidic towards moderately acidic), soil organic carbon (p ≤ 0.05; an increase from 4% to over 100%), soil water availability (an increase from 1% to 15%), saturated hydraulic conductivity (an increase from 5% to 95%). The effects were more significant in the following cases: repeated rather than single biochar application, higher rather than lower biochar application rates, and higher rather than lower N fertilization levels. Initial and repeated biochar applications, leading to N2O emissions reduction, can be related to increased soil pH(KCl).

One of the challenges of harnessing higher productivity levels and sustainability of agriculture related to N fertilization is in expanding soil N2O emissions, which has become a serious issue in recent years. Recent studies suggest that biochar may be the solution to this problem, but there is still a knowledge gap related to biochar application rates and its reapplication in Central Europe; therefore, in this study, we investigated the effect of biochar (initial application and reapplication in 2014 and 2018, respectively, at rates of 0, 10 and 20 t ha−1) combined with N-fertilizer (N0—0 kg N ha−1; N1—108 kg N ha−1 and N2—162 kg N ha−1) during the growing season of maize in 2019 (warm temperature with normal precipitation) on the changes of soil properties and N2O emissions in the silty loam, Haplic Luvisol, in the temperate climate of Slovakia. The results showed that the application and reapplication of biochar proved to be an excellent tool for increasing soil pH (in the range 7–13%), soil organic carbon—Corg (2–212%), and reducing the soil’s NH4+ (41–69%); however, there were more pronounced positive effects when biochar was combined with N-fertilizer at the higher level (N2). The same effects were found in the case of N2O emissions (reduction in the range 33–83%). Biochar applied without N-fertilizer and combined with the higher fertilizer level had a suppressive effect on N2O emissions. Biochar did not have any effect on maize yield in 2019.

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.

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Biochar application to agriculture soil has been recommended as a strategy to reduce increasing atmospheric carbon dioxide (CO2) concentrations and mitigate climate change. Significant suppression of soil CO2 emissions following biochar amendments has been demonstrated in short-term laboratory incubations by several authors, yet evidence from long-term field trials has been contradictory. This study investigates whether biochar addition to the soil could suppress soil CO2 emission under field conditions after 6�th years following amendment. CO2 emissions were not significantly suppressed with biochar addition, although they were generally low. Biochar amendment suppressed soil cumulative CO2 emissions by 30.59%. These findings demonstrate that biochar amendment has the potential to suppress soil CO2 emissions in corn crop system after 6�th years of biochar application. We conclude that the concentration of soil CO2 emissions were depended on soil temperature measured during study period.

Biochar application to agriculture soil has been recommended as a strategy to reduce increasing CO2 emission in the atmosphere and mitigate climate change. In this study, we evaluated the impact of two doses of biochar (10 and 20 t.ha−1) applied in 2014 and reapplied in 2018 combined with three fertilization levels (N0, N1, N2) on carbon dioxide emissions and selected physical and chemical soil properties in field conditions during spring season (April–June) in 2020. The field site is situated in the Nitra region of Slovakia (Malanta). The soil in the field was classified as a silt loam Haplic Luvisol. In this field research it was found that biochar application mostly in all treatments decreased cumulative CO2 emissions in rage from 4.2% to 30.4% compared to controls (B0N0, B0N2), except treatments where biochar was applied with lower level of N-fertilizer (N1) and treatment B20N0. According to our study results, it was confirmed that biochar can be a promising material for improving soil physical and chemical properties. Mainly, it has very good impact on soil pH, even after seven years of field experiment established. However, the response of soil CO2 fluxes to biochar application were regulated mainly by experiment length, biochar application rate, biochar properties, giving a new perspective for more comprehensive understanding on biochar.