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 (1961-2015) 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 1 week over the investigated 55 years. Projected changes in the timing of phenological phases which define limits of a main vegetation period differ essentially from the observed period. According to pessimistic (Representative Concentration Pathways 8.5) scenario, the advancement of winter wheat maturity phase by almost 30 days and the shortening of post-winter vegetation season by 15 days are foreseen for a far (2071-2100) projection. An increase in the available chilling amount is specific not only to the investigated historical period (1960-2015) but also to the projected period according to the climate change scenarios of climate warming for all three projection periods. Consequently, the projected climate warming does not pose a threat of plant vernalization shortage in the investigated geographical latitudes.

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Though the number of climate-change-related agro-phenological investigations are growing rapidly, the attention paid to spring crops has been much less than to winter ones. The objective of the current study was to investigate long-term temporal and spatial trends of spring barley phenology and to project changes in the timing and duration of different phenological phases during the current century. Higher temperatures significantly affected the potential scheduling of agricultural practices, accelerating the occurrence of sowing and emergence dates. Historical trends in harvest dates of spring barley showed a slight delay. These changes resulted in the extension of the total vegetative period of spring barley by >12 days over the period investigated (1961–2015). Since Lithuania is situated on the Baltic Sea, an increase in temperature along with an increase in distance from the sea was characteristic over the last 55 years. Projected changes in the occurrence of phenological phases of spring barley differ significantly from analysed historical changes and advancement of all phenological phases have been projected according to both Representative Concentration Pathway (RCP) 2.6 and RCP 8.5 climate change scenarios. Shortening of the total vegetative period by 5 days is foreseen for the far (2071–2100) future according to the pessimistic (RCP 8.5) climate change scenario.

Darbe tirtas azoto trąšų poveikis skirtingų žieminių kviečių veislių fotosintetinių rodiklių dinamikai. Lauko eksperimentas vykdytas 2012–2013  m. Aleksandro Stulginskio universiteto Bandymų stotyje, karbonatingame sekliai glėjiškame išplautžemyje <i>Calc(ar)i-Epihypogleyic Luvisol</i>. Tyrimo objektas – gerų kepimo savybių žieminių kviečių veislės ‘Kovas’, ‘Olivin’. Sėjos metu kviečiai buvo tręšti vienanarėmis fosforo, kalio trąšomis (P₆₀K₆₀), o pavasarį, atsinaujinus vegetacijai, – amonio salietra (N₆₀). Papildomai per lapus tręšti karbamido tirpalu (N₃₀, N₄₀) bamblėjimo ir (N₁₅, N₃₀) pieninės brandos tarpsniais. Tyrimų metu nustatyta, kad papildomas tręšimas N₃₀ ir N₄₀ azoto normomis vėlyvaisiais augalo vystymosi tarpsniais skatino fotosintezės pigmentų kaupimąsi ir prailgino aktyvios fotosintezės periodą. Veislės genetiniai ypatumai turėjo įtakos pigmentų kau­pimuisi nepriklausomai nuo tręšimo azoto trąšomis. Gerų kepimo savybių kviečių veislė ‘Kovas’ linkusi kaupti didesnius fotosintezės pigmentų kiekius. Didžiau­sias pig­mentų kiekis nustatytas pieninės brandos pradžioje prieš papildomą tręši­mą N₁₅, N₃₀ trąšų normomis. ‘Olivin’ veislės žieminiai kvie­čiai turi didesnį grynąjį fotosintezės produktyvumo potencialą nei ‘Kovas’ veis­lės kviečiai. Intensyviausiai ‘Olivin’ veislės augalų fotosintezė vyko nuo vamzdelėji­mo iki pieninės brandos tarpsnio (BBCH 43–74), tręšiant N₆₀ + N₄₀, o ‘Kovas’ veislės kviečių – N₆₀ + N₃₀ azoto normomis.

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