Kanapickas, Arvydas

Siekiant padidinti žieminių kviečių produktyvumą, būtina užtikrinti tinkamą augalų mitybą ir suformuoti optimalaus tankumo pasėlį. Tam tikslui 2022–2023 metais Vytauto Didžiojo universiteto Žemės ūkio akademijos Bandymų stotyje atliktas eksperimentas. Dviejų veiksnių eksperimente tirta sėjos laiko ir tręšimo mikroelementinėmis trąšomis įtaka žieminių kviečių produktyvumui. A veiksnys – sėjos laikas: rugsėjo 6 d., rugsėjo 13 d., rugsėjo 20 d., rugsėjo 27 d. B veiksnys – papildomas tręšimas mikroelementinėmis trąšomis (Mn – 0,3 kg ha-1 , Cu – 0,05 kg ha-1 , Zn – 0,2kg ha-1 ). Kviečiai papildomai tręšti du kartus – BBCH 30–31 ir BBCH 32–33 tarpsniais. Išanalizavę tyrimo rezultatus, galime teigti, kad augalus papildomai tręšiant mikroelementinėmis trąšomis žieminiai kviečiai formavo tankesnį pasėlį, daugiau grūdų varpose bei didesnę 1 000 grūdų masę. Daugiausia produktyvių stiebų (596 vnt. m-2 ) bei grūdų varpoje (66 vnt.) nustatyta vėliausiai (rugsėjo 27 d.) pasėtų ir mikroelementinėmis trąšomis patręštų žieminių kviečių laukeliuose. Papildomas tręšimas reikšmingai padidino (0,4 t ha-1 ) žieminių kviečių, pasėtų rugsėjo 6 d., derlingumą.

Wind energy is one of the main renewable sources in Lithuania. Rural regions are suitable for wind farms due to open landscapes, good wind conditions and low settlement density. Previous research focused on climate change, but the effect of urbanisation was rarely analysed. This study evaluates how different urban growth rates change wind characteristics and electricity generation. The analysis used wind speed observations from 22 meteorological stations (1990–2020). These data were combined with projections from seven global circulation models under three Representative Concentration Pathway (RCP) scenarios: RCP2.6 (minimal emissions), RCP4.5 (medium emissions, current policies trajectory), RCP8.5 (high emissions). Urbanisation was represented by three growth rates: slow (200 years), moderate (100 years) and fast (50 years). They correspond to increasing surface roughness and turbulence. Wind speeds were calculated for hub heights of 100 m and 150 m. Two turbine types were considered: Enercon E-112 and E-126. Energy yield was estimated for a 25-year turbine lifetime. The results show that climate change has only a small impact. Wind speed decreases by less than 8%, and electricity generation declines only slightly. Urbanisation has a much stronger effect. Energy yield falls by 28–32% under slow expansion, by 39–45% under moderate expansion, and by more than 50% under fast growth. Coastal regions remain the most productive, but inland areas are more vulnerable. Higher turbines increase output, but they cannot compensate for roughness. Assessments that ignore urbanisation tend to overestimate long-term wind energy potential. Including land-use change gives more realistic information for rural development, energy planning and spatial policy in Lithuania.

Sowing date is a particularly important management option to optimize yields as it determines proper wintering and productivity. During a seven-year field experiment, the response of winter wheat to five different sowing times was studied. The beginning of the dormancy period was determined, and the Growing Degree Day (GDD) requirements for the period from sowing to emergence and from emergence to dormancy were assessed. As the sowing date was delayed, the time from sowing to emergence increased. The minimum optimum temperature during the emergence period was about 12 °C, with a heat requirement of about 125–130 GDD for earlier sowings, ensuring that winter wheat germinated successfully and properly prepared for wintering. The heat requirement for later sowings was higher and reached about 180 GDD when the average temperature of this period was about 8 °C. For the late sowing, the period from emergence to dormancy was too short, so winter wheat did not accumulate the required amount of heat, which had a significant impact on yield. The accumulated temperature from emergence to dormancy must be greater than 100 GDD. The obtained values can be applied in other regions or to choose the appropriate wheat sowing time to reduce yield losses under climate change.

Wind energy is one of the most important ways to implement green energy in Lithuania. The development of wind energy infrastructure by state funding is directly related to wind energy resources. Changes in wind energy resources induced by ongoing climate change have not been well analyzed either in Lithuania or in Europe or worldwide. This article analyses data taken from long-term wind observations and IPCC projections. It was found that during the last decades (1980–2019), the wind speed in Lithuania decreased up to 0.69 m/s in the coastal region and up to 0.24 m/s in the central part of Lithuania. The decrease in wind speed caused a decrease in generated energy by 15.6 % and 17.8 % in the coastal and the central parts of Lithuania. Analysis of wind speed projections for the period 2010–2100, according to the RCP4.5 scenario, has shown that the average annual wind speed would decrease by 7.3 % in Lithuanian’s coastal region and 8.8 % the central region by the end of the century. The change in wind speed will cause up to a 25 % reduction in wind potential. As the average lifetime of wind turbines is about 25 years, the amount of electricity generated during this period will be up to 20 % lower than planned at the design stage.

It is essential to understand how climate change and varieties affect crop phenology and yields to adapt to future climate change. The aim of this study was to analyse the phenological development trends of three winter wheat cultivars (1990–2020) to identify the most critical meteorological-climatic factors influencing the development and yield of the cultivars and to investigate the heat requirements for each phenological phase to reveal the potential of the different cultivars to adapt to the warming climate. The observed dates of green-up, the beginning of stem elongation, and the grain development advanced significantly, but the timing of maturity changed insignificantly during the period of 1990–2020. The most marked change was related to the shortening of the period from sowing to green-up. The green-up dates were related to the mean temperature of the period after sowing. The occurrence of stem elongation and grain development dates were negatively correlated with the mean temperature in May. Significant correlations were found between temperature and duration from sowing to green-up and positive from stem elongation to grain development. The change of cultivar led to earlier green-up and grain development dates, but cultivar choise had no influence on sowing, stem elongation, and maturity dates from 1990 to 2020. The newer cultivar Skagen was more successful in exploiting increased thermal resources. The heat requirements remained almost unchanged during the vegetative development period, while the heat amount required during the reproductive period increased by about 15%. These findings demonstrate that the choice of crop cultivars with higher thermal requirements may be an appropriate adaptation mean to achieve higher yields in response to climate change, at least in the middle latitudes.

Climate change is encouraging countries to consider alternatives to fossil fuels [1]. One such alternative is wind power. Currently, Lithuania generates about 14 % of its annual demand using wind energy. However, this is too low to meet the European Union's target of at least 32 % renewable energy by 2030 [2], [3]. To estimate how much energy could be generated to the maximum possible extent, the Intergovernmental Panel on Climate Change (IPCC) reports need to be taken into account, as well as the projected future wind change and the locations where wind energy development is possible. The following objectives are intended to be addressed by this study. First and foremost, a suitable location for wind farm development must be identified. Second, using the SSP2-4.5 climate change projection, analyse the impact of climate change on energy output throughout the next 40 years (2021–2060). Finally, consider how much electricity might be generated if wind turbines were installed in all permissible places in Lithuania, as well as if this would assist Europe to reach its renewable energy targets.

Developing wind energy in Lithuania is one of the most important ways to achieve green energy goals. Observational data show that the decline in wind speeds in the region may pose challenges for wind energy development. This study analyzed the long-term variation of the observed 2006–2020 and projected 2006–2100 near-surface wind speed at the height of 10 m over Lithuanian territory using data of three models included in the Coupled Model Intercomparison Project phase 5 (CMIP5). A slight decrease in wind speeds was found in the whole territory of Lithuania for the projected wind speed data of three global circulation models for the scenarios RCP2.6, RCP4.5, and RCP8.5. It was found that the most favorable scenario for wind energy production is RCP2.6, and the most unfavorable is the RCP4.5 scenario under which the decrease in wind speed may reach 12%. At the Baltic Sea coastal region, the decline was smaller than in the country’s inner regions by the end of the century. The highest reduction in speed is characteristic of the most severe RCP8.5 scenario. Although the analysis of wind speeds projected by global circulation models (GCM) confirms the downward trends in wind speeds found in the observational data, the projected changes in wind speeds are too small to significantly impact the development of wind farms in Lithuania.

Field experiments were carried out at the Experimental Station of Vytautas Magnus University Agriculture Academy in Lithuania (54° 53' 3.26", 23° 50' 33.25") during 2017-2018. Six winter wheat varieties were studied in the experiment: 'Skagen' (control), 'Julius', 'Edvins', 'Artist', 'Aron' and 'Evina', which were sown on September 15. Preceding crop – winter rape. Seed rate – 4.5 million ha-1. The aspects of the dynamics of photosynthesis pigments in winter wheat leaves depending on variety is analysed in the article. Physiological activity of the plant, the growth and development are the most important moments decisive the accumulation of these pigments in the plant. Thus, the general condition of the plant might be described by the composition and content of photosynthesis pigments chlorophyll a, b and carotenoids. Spectrophotometric Wettstein method and “Genesys” 6 spectrophotometer were used for determination of the content of photosynthesis pigments (chlorophyll a, b and carotenoids) in green leaf mass in 96 % ethyl alcohol extract.The accumulated amounts of photosynthetic pigments (chlorophylls a, b and carotenoids) in different varieties of winter wheat leaves differed. Winter wheat variety 'Aron' accumulated the highest contents of photosynthetic pigments during the tillering and stem elongation stages, meanwhile during the heading – anthesis and early milky maturity stages winter wheat varieties 'Artist' and 'Skagen' demonstrated the best results. The LAI of different varieties of winter wheat differed in the field experiment. Significantly higher LAI was defined for winter wheat variety Artist (0.9) after the resumption of vegetation (BBCH 24–27) and for 'Skagen' (4.0) at the end of vegetation (BBCH 70–73). The highest LAI of winter wheat is determined during the heading - anthesis stage (varieties 'Aron', 'Edvins', 'Skagen'). During the growing season, the lowest LAI was observed for winter wheat variety 'Evina'.

Global warming is gaining significance as a threat to ecosystems, since temperature is one of the major abiotic constraints to productivity. Considering that better understanding of the effects of climate change on phenological development of field crops may help to optimize their management schemes and increase productivity. But most of attention is concentrated on winter crops leaving spring crops aside. The purpose of this study was to trace long-term spring barley phenology trends, and to predict changes in different phenological phases timing and duration, for the current century. The purpose of this study was to trace long-term spring barley phenology trends, and to predict changes in different phenological phases timing and duration, for the current century. The temporal and spatial phenological trends of spring barley (Hordeum vulgare L.) over the period of 1961-2015 were analyzed using data of the phenological observation network at 7 phenological sampling sites located throughout Lithuania. Over the investigated period mainly two cultivars (Auksiniai II and Auksiniai III) were grown in the study area. For future climate, five global circulations models (GCMs)(MPI-ESM-LR; IPSL-CM5A-LR; CNRM CM5; HadGEM2-AO and HadGEM2-ES), were selected, together with two highest contrasting future climate change scenarios - RCP2.6 and RCP8.5. For the phenological analysis the amount of accumulated temperature required for the occurrence of the following phenological phases of spring barley were evaluated: sowing, emergence, heading, and harvest. It was found that temperature increase significantly affected agricultural management schedule by altering the occurrence of sowing and emergence dates. Retrospective trend of spring barley harvest dates showed rather a slight delay [...]

Climate warming and a shift in the timing of phenological phases, which lead to changes in the duration of the vegetation period may have an essential impact on the productivity of winter crops. The main purpose of this study is to examine climate change related long term (19612015) changes in the duration of both initial (pre-winter) and main (post-winter) winter wheat vegetation seasons, and to present the projection of future phenological changes until the end of this century. Delay and shortening of pre-winter vegetation period, as well as the advancement and slight extension of the post-winter vegetation period resulted in the reduction of whole winter wheat vegetation period by more than one week over investigated 55 years. Projected changes in the timing of phenological phases which define limits of a main vegetation period differ essentially from observed period. According to pessimistic (RCP 8.5) scenario, the advancement of winter wheat maturity phase by almost 30 days and the shortening of postwinter vegetation season by 15 days is foreseen for a far (2071-2100) projection. An increase in the available chilling amount is specific not only of investigated historical period (1960-2015) but also of projected according to both climate change scenarious climate warming for all three projection periods, including far projection (2071-2100). Consequently, the projected climate warming does not pose a threat of plant vernalization shortage in the investigated geographical latitudes.