Autumn Frost Research Articles

Autumn Frost Hardiness in Six Tree Species Subjected to Different Winter Storage Methods and Planting Dates in Iceland

Autumn Frost Hardiness in Six Tree Species Subjected to Different Winter Storage Methods and Planting Dates in Iceland

Impact of Climate Change on the Development of Viticulture in Central Poland: Autoregression Modeling SAT Indicator

Ongoing climate change is having a profound impact on agriculture, which is attracting attention from the scientific community. One of its effects is an increase in average temperature, which is a key factor in grape cultivation. This may increase the popularity of viticulture in central Europe. The aim of this study was to assess the potential for the development of viticulture in central Poland based on SAT changes from 1975 to 2021, in addition to changes in evapotranspiration, occurrence of late spring and early autumn frosts and frosty days in selected years from this period as an important factors relating to climate change. The research utilized data obtained from the Institute of Meteorology and Water Management—National Research Institute. The Bai–Perron test was used to determine the direction of temperature changes. An AR(1) autoregression model was used to predict SAT changes in central Poland for the years 2022–2026, based on the results of the Bai–Perron test. As part of the in-depth research on the SAT index, reference evapotranspiration calculations were also made as a second factor that is considered an important indicator of climate change. The Sum of Active Temperatures from 1975 to 2021 in the provinces of central Poland showed an increasing trend of 0.07% per year. The average SAT in central Poland in 2022–2026 is expected to range from 2700 °C to 2760 °C. Considering the current thermal conditions in central Poland and the forecasts for the coming years, it can be expected that vineyard cultivation will develop in this region. However, the research shows that the observed increasing trend in evapotranspiration, both in total in individual years and in the period of the greatest vegetation, i.e., in the months from May to the end of August, will result in an increasing need in central Poland to ensure adequate irrigation in developing vineyards.

FEATURES OF AGRO INSURANCE IN AUSTRIA AND GEORGIA

Insurance is a risk management financial instrument that involves the transfer of risk in whole or in part to an insurance organization. Crop insurance in agriculture is of great importance. Thus, the implementation of the agro insurance program is very relevant and vital for the farmer. Properly managed agricultural reform and the development of agro insurance will contribute to economic growth, country development and the well-being of the population. The main functions of agro insurance are to facilitate agricultural production and to compensate for the damage caused by the realization of agro risks. Agro insurance is a sub-type of property insurance that reduces risk for the farming sector and stimulates the development of agricultural production. Thus, the implementation of agro insurance is important for the farmer. The purpose of the paper is to compare the peculiarities of agro insurance between the two countries. The objectives of the study are to study the situation in the agro insurance market of Georgia and Austria, to analyze the state agro insurance program. It should be noted that the governments of both countries subsidize agro insurance. The difference is that 70% of the insurance premium in Georgia is subsidized and 50% in Austria. The main four risks in Georgia are insured: hail, storm, flood, autumn frost (citrus only). In Austria, a wider insurance package is offered to farmers, taking the following risks: hail, frost, storm, flood, snow, drought, fire. It should be noted that agricultural insurance has been helping farmers to compensate for the damage caused by insurance risk in Austria since 1947. In Georgia, this product is quite young only covers 12 years and requires time to develop more and farmers understand its goodies. Keywords: agro insurance, income stabilization, agro risks, financial loss.

Taxonomy of the <i>Typhula ishikariensis</i> complex in Russia

The purpose of this publication is to show the history of the taxonomy of the Typhula ishikariensis complex and to provide more detailed geographical descriptions of those fungi in Russia. Three features on the description of this complex species are noted: morphological, crossing and molecular. Often, species described on different host plants have been recognized as synonyms of another previously described species, for example, T. humulina isolated from hop rhizomes and T. graminearum from first year seedlings of Pinus sylvestris and grass weeds have been synonymized with Typhula idahoensis. The latest work by Hoshino et al. distinguished four taxa (three species) based on dendrograms obtained by ITS and ribosomal DNA sequencing, crossing results, morphological and physiological characters: T. ishikariensis var. ishikariensis, T. ishikariensis var. idahoensis, T. hyperborea, and T. canadensis. T. ishikariensis var. idahoensis was found only in North America, and the last two species (T. hyperborea and T. canadensis) mainly in areas with extreme winter conditions. In Russia, Typhula ishikariensis var. ishikariensis, was recorded in the European part of Russia beyond the Arctic Circle: Apatity (Kola Peninsula), in places with a temperate climate: Moscow, St. Petersburg, the republics of Chuvashia and Mari El; and in Asia with a more severe climate: Sverdlovsk Region, Novosibirsk, Irkutsk Region (Hamar-Daban) and Sakhalin. T. canadensis and, presumably, the oldest T. hyperborea, inhabit mainly in areas with unstable and severe winter climates. T canadensis in Russia was noted by us in Asia in the Baikal region in the Ice Age refugium Khamar-Daban, Kamchatka and Sakhalin, and T. hyperborea in Asia in the Sverdlovsk region, Novosibirsk, Kamchatka and Chukotka (Anadyr), along with the European regions of Russia with a temperate climate in the Volga republics of Mari El and Tatarstan. These areas are characterized frequent autumn frosts, which promoted competition with another snow mold pathogen, the necrotroph Sclerotinia borealis. Underground damage of plant tissues, such as tulip bulb bases and roots, and hop rhizomes by T. ishikariensis var. ishikariensis occurred only in Russia. Perhaps the diversity in winter climate evolved and preserved diverse taxa, including ancestral forms. Obviously, such climatic fluctuations evolved organisms capable of survival under unstable stressful conditions, especially when climatic conditions change.

Особенности развития видов Verbascum в Центральной Якутии

The possibility of cultivating mullein species in Central Yakutia, which are relatively undemanding plants in terms of moisture, is of scientific and practical interest in order to determine their biological potential and the possibility of using them as ornamental and medicinal plants. The aim of the work is to identify the peculiarities of the developmental rhythms of some species of the genus Verbascum in the permafrost conditions of Central Yakutia. The objects of the study were 11 samples of the species V. chaixii subsp. austriacum, V. densiflorum, V. nigrum, V. nigrum subsp. abietinum, V. phoeniceum and V. thapsus. The material was obtained in the form of seeds in 2018–2021 from institutions in Russia, Denmark, Romania and Poland. The seeds of the first V. phoeniceum sample were sown in a greenhouse and the resulting seedlings were transplanted into the field collection. The remaining seeds were sown outdoors in the second half of September. The plants overwintered under the snow without any additional protection. Phenological phases in the conditions of Central Yakutia were 3–4 weeks later in the calendar than in Central Russia; the end of the growing season was limited by the onset of autumn frosts. The results of the introduction in Central Yakutia showed high resistance in culture of the species V. phoeniceum, V. nigrum, V. nigrum subsp. abietinum, V. chaixii subsp. austriacum and V. thapsus. When sown in the fall, plants of these species flower profusely in the second year and produce mature seeds, except for V. chaixii subsp. austriacum, which flowers profusely in the first year. These species are very decorative and can be recommended for inclusion in the range of ornamental herbaceous plants for Central Yakutia. V. thapsus is also promising as a medicinal plant. V. densiflorum plants developed as annuals without having time to form mature seeds. To use V. densiflorum as an ornamental or medicinal plant, a seedling period is required.

FEATURES OF MAIZE GROWING FOR GRAIN IN THE WESTERN FOREST ZONE OF UKRAINE IN THE CONDITIONS OF CURRENT CLIMATE CHANGES

Modern climatic changes, namely significant warming in the northern Forest-Steppe and Polissia zones of Ukraine, provide opportunities for the cultivation of a number of grain and leguminous crops (maize for grain, soybeans, sunflower, and others), previously uncharacteristic of this region. Among the above-mentioned crops, corn has the greatest grain yield potential, therefore it is one of the most common crops in world agriculture. If 10-15 years ago corn was not grown for grain in the Polissia zone, then in recent years its sown areas have grown significantly, and the yield in some years is not inferior to the regions of the Forest Steppe and Steppe, which are traditional for this crop. The results of experimental studies of the station showed that under favorable conditions on the most fertile slopes of the drained sod-podzolic soils of the Western Polissia zone, with intensive technologies, it is possible to obtain more than 10-12 t/ha of corn grain.
 The analysis of hydrothermal indicators shows that with the current indicators of heat supply of the growing season in the zone of Western Polissia on mineral soils, it is possible to achieve not only early-ripening, but even medium-early hybrids of corn with FAO up to 280-300. Drained peat soils, due to their high nitrogen content and sufficient amount of moisture, have sufficient potential for obtaining a high yield of corn grain. However, its indicators over the years of research vary greatly and depend to a large extent on the agro-meteorological conditions of the growing season. It has been established that the main limiting factors for achieving a high yield of corn grain on peat soils are less favorable microclimatic features (less amount of active heat, shorter growing season and frost-free period, etc.) compared to adjacent sod-podzolic soils located nearby on dry land. It has been experimentally established that under conditions of minimum duration without a frost period, only the most early-ripening hybrids of corn with FAO up to 220-240 will have time to form a full-fledged crop of grain on drained peat soils in the Western Polissia zone. By choosing late-ripening hybrids, there is a risk of a significant shortfall in the harvest due to the premature termination of vegetation caused by early autumn frosts. It was established that the highest yield of corn per grain, both on sod-podzolic and peat soils, was provided by the organo-mineral fertilization system, which was based on the application of complete mineral fertilizer at the rate of N90Р90К90 on turf-podzolic soils and N35Р60K120 on peat soils in combination with phosphorus mobilizing drug Rice Pi. The use of the organo-mineral fertilization system (N90Р90К90 + phosphorus mobilizing drug Rice Pi) ensured an increase in the yield of corn on sod-podzolic soils by 30,2 ct/ha compared to the basic fertilization system (N30Р30К30). The use of the organo-mineral fertilization system (N35Р60K120 + phosphorus mobilizing drug Rice Pi) ensured an increase in the yield of corn on peatlands by 56.8 ct/ha compared to the natural background of fertility.

Monitoring of a <i>Cypripedium guttatum</i> (Orchidaceae, Liliopsida) population on the northern border of its distribution range (Komi Republic, European Russia)

The results of our 12-year study of a population of the rare orchid Cypripedium guttatum Sw. on the northern border of its range, on the territory of the Komi Republic (north-east of European Russia) are presented. Our research has shown that weather factors (temperature and precipitation) have an impact on the seasonal development of shoots and plant size. The number of shoots is influenced by the weather conditions of the previous growing season, namely: the temperature of the first decade of August influences positively while early autumn frosts and the amount of precipitation of the entire period do negatively. A negative correlation was found between the number of flowering shoots and the temperature of the second decade of July of the previous growing season and a positive relationship between the number of juvenile plants and the precipitation of August of the previous growing season. Fruit set was quite low (17.1%), which is typical for this species. The pollination efficiency of C. guttatum was negatively affected by the high temperature during its flowering (the second decade of June). One box contained an average of 4065 seeds. The real seed productivity per shoot varied from 1989 to 7064 pcs., it is associated with precipitation in the second decade of July of the current growing season. The high number of the population studied (25 thousand shoots), the correspondence of the ontogenetic spectrum to the basic one of the species, the annual presence of juvenile plants of seed origin indicates its stable condition.

VARIABILITY OF ECONOMIC VALUE CHARACTERS IN COMMON VARIETIES OF HAZELNUT IN THE TRANSCARPATHIAN REGION

The frost-free period according to average long-term data lasts 170-180 days. The average date of termination of the last spring and the beginning of the first autumn frosts falls on April 18 and October 16, respectively. The deadlines for the earliest and latest cessation of spring frosts are March 23 and May 12, and the beginning of autumn frosts is September 20 and November 12. Thus, the duration of the frost-free period can vary from 146 to 215 days, which significantly affects the reduction of growth processes or freezing of young shoots and fruit buds. the optimal year for the vegetation period was 2019. The year 2020 was very unfortunate for all fruit crops, because it was accompanied by freezing of all types of buds, which did not contribute to the formation of the crop properly and delayed the formation of first-wave shoots for a decade in both varieties. Observing the severely frozen bushes, they noted the lag in leaf growth and the absence of shoots of the first wave, which means the weak development of earrings, which begin to form in June. This state of development will complicate the pollination of the next crop. The development of female buds was noted on the shoots of the second wave, which should give the expected harvest for 2021 when creating conditions for pollination. It should be noted that on some bushes young shoots did not recover, and very frozen parts dried up by mid-summer. In the future, it is necessary to provide smoking and other methods of insulation to prevent damage from late frosts. According to the amount of precipitation, the experimental field belongs to the zone of sufficient moisture. During the year, precipitation is distributed according to average long-term data, the amount of precipitation that falls in winter is only 17% of the annual amount, in spring and autumn 23% and in summer 37%. Therefore, for effective disclosure of the potential of varieties, drip irrigation was carried out, which makes it possible to increase the return on investment. When laying the fields, we decided on the formation of a bush with three to six productive branches placed in a circle. During the vegetation of the third year, 1-2 one-year shoots are formed for future replacement. After flowering, each bush is carefully inspected, patients are pruned, which are intertwined, which allows you to light well and not be affected by powdery mildew. The condition of the bushes for the third year of the growing season is good according to all expectations from the varietal characteristics. Keywords: hazelnuts, varieties, frost resistance, productivity, diseases

Influence of spring and autumn frosts on Impatiens glandulifera populations in the Sofia region (Bulgaria)

The present study aims to analyze and determine to what extent spring and autumn frosts affect the population size and life cycle of this invasive alien species (IAS). The study area is located in the immediate vicinity of the capital Sofia and covers the  Iskar River stream and its tributaries in the gorge between Plana and Lozenska Mountains (Southwestern Bulgaria). The study was carried out in the period 2020-2022. Six permanent sample plots (PSP), each measuring 10 m2, were established in characteristic localities of I. glandulifera populations along the Iskar River and its tributaries (Table 1). Each year, during the spring and autumn frosts, the percentage of dead individuals of I. glandulifera relative to the total number of individuals of this species in the PSP was recorded. During the autumn frosts, the number of alive individuals in the following phenological stages was also recorded: flowering; fruiting; dispersal of fruits and seeds; end of growing season. The results show that frosts in the study area did not significantly affect the population size and life cycle of I. glandulifera. The death of the whole population оccurs only in permanent periods of negative daytime temperatures, however a significant part of the individuals at that time are in a generative stage of development. The temperature conditions in the area favor the invasiveness of I. glandulifera, extending the vegetation period of this species and the possibilities for its reproduction and spread.  

Weather and climate and their human impacts and responses during the Thirty Years' War in central Europe

Abstract. The Thirty Years' War, which took place from 1618 to 1648 CE, was an armed military conflict in Europe. It resulted from the culmination of theological differences between advocates of the Roman Catholic and Protestant churches, as well as a power struggle for European political hegemony. This war brought about extensive devastation to Europe. Based on documentary evidence, this paper characterizes the climate, weather extremes, and economic and socio-political events in central Europe during that time. Natural climate forcing indicates a gradual climate deterioration during the first half of the 17th century, associated with a decrease in solar activity towards the Maunder Minimum and increased volcanic activity. The mean temperatures in central Europe from 1618 to 1648 were significantly colder than the reference period of 1961 to 1990 in winter, autumn, and annually, while precipitation and drought means did not differ significantly from the reference period. Summer temperatures, spring precipitation, and drought also exhibited significantly greater variability. As for weather extremes, particularly late winter, late spring and early autumn frosts, floods, intense rain spells, and droughts affected grain, fruit, and vine grape harvests, as well as the yields of other crops. These weather extremes contributed to various human impacts, such as food shortages (reflecting harvests and grain prices), famines, and epidemics. Ultimately, these events, along with the effects of the war, led to a decline in the population. The results obtained are discussed within the broader European context, taking into account climate, weather extremes, and socio-economic impacts.

The effect of gene flow on frost tolerance in Scots pine – Latitudinal translocation of genetic material

Extensive gene flow can be detrimental to local adaptation and similarly, forestry seed sources such as seed orchards can be heavily influenced by external pollination, especially if the orchard material has been translocated a great distance. Here we conducted a coordinated genotyping-phenotyping study to examine how external pollination events and fecundity variation in a Pinus sylvestris seed orchard influence the genetic composition and the seed-lots’ autumn frost hardiness when genetic material had been translocated 630 km south. The results were then compared to those of a in situ established seed orchard. We genotyped and phenotype >1000 seedlings from these orchards, and constructed their pedigrees and scored their autumn frost tolerance in a controlled climate chamber environment. The hardiness scores were compared with a reference of nine natural stands along a latitudinal cline. We find substantial variation in fecundity and external pollination over crop years, thus unpredictable genetic composition because the contribution of some orchard clones is high in one crop but low in another. We observed that seedlings produced by mating among orchard genotypes were less hardy than expected (corresponding to an origin of −0.6°N) but the opposite in externally pollinated seedlings (+0.3 to +0.7°N). The freeze damage levels reflect the origin of parental genotypes, but to a smaller degree than expected (13% lower than expected damage levels for externally pollinate seedlings and 21% greater damage levels for internally pollinates seedlings). These results suggest that orchard parents’ origins, mating composition and orchard local environment could all affect the seed crops’ quality and their climate adaptation. Seed orchard crops are the key to realize the gain in forestry from breeding efforts. However, genetic monitoring of seed crops is necessary to improve the performance of seed orchards further and adjust deployment areas of seed crops in a timely manner for a more dynamic forestry, considering climate change and biodiversity demands.

Common garden study reveals frost-tolerant northern seed sources are best suited to expand range of Quercus rubra

Climate change is shifting the potential suitable range of northern red oak (Quercus rubra L.) faster than it can migrate, creating an adaptation lag.Quercus rubrais prominent in eastern North American forests and important for its carbon sequestration, ecological functions, and economic significance. Our study addresses which populations ofQ. rubraare best suited for climatic conditions at its northern and central United States range limits. Our findings can inform management decisions involving assisted migration, where species are transferred within their native range to mitigate the effects of climate change. We planted over 800 Q. rubra seedlings from twelve populations representing the current Q. rubra geographic range in two common gardens, one at the northern range limit (Alberta, Michigan, USA) and one in the central range (Kalamazoo, Michigan, USA). We observed Q. rubra aboveground growth, phenology (senescence, budburst), and frost damage for three years.At the central range site, southern seed source populations from warmer and wetter locations showed greater relative growth rate. At the northern range site, northern seed sources, from colder, drier locations, had greater relative growth rate. Southern seed sources generally had later phenological events which resulted in them sustaining more frost damage than northern seed source populations in the spring and autumn. Northern seed sources had earlier budburst and were able to utilize early growing season snow melt and higher solar radiation. Northern seed sources also senesced earlier, avoiding autumn frosts. More extreme weather events are predicted with climate change, which favors the phenology, frost tolerance, and greater growth rate of northern seed sources for assisted migration at the northern range limit.

Comparative assessment of pumpkin varieties in the Udmurt Republic

Relevance. Pumpkin is a food, medicinal and fodder crop of the Cucurbitaceae family. It is valued for its high content of vitamins, minerals, organic acids. At present, thanks to the huge variety of species and modern selection, it is possible to select pumpkin varieties for cultivation in almost any region, including areas with short and not too hot summers. Udmurtia belongs to the zone of risky farming, the end of spring frosts is observed on average in the first ten days of June, and autumn frosts on the soil are possible at the end of August. Due to the short frost-free period, it is necessary to choose earlier maturing varieties, grow the crop through seedlings and use temporary shelters. The pumpkin fruit is usually large in size, is a thick layer of pulp, covered with a dense peel. When cutting such a fruit, the pumpkin is not stored in the future, it requires urgent processing. In this connection, in recent years, portioned varieties of pumpkin, the size of the fruit of which does not exceed 1.5–3.0 kg, have become increasingly in demand.Materials and Methods. The purpose of the research: a comparative assessment of varietal characteristics of growth and productivity of pumpkin species. In 2020–2021 in the conditions of the Udmurt Republic, experiments were carried out to study the characteristics of growth and productivity of pumpkin varieties. We studied varieties of pumpkin: Pearl, Crumb, Honey Tale, Marble, Rossiyanka, Smile, Candied fruit.Results and its discussion. Within two years, pumpkin varieties of large-fruited and nutmeg were studied. On average, for two years, the pumpkin Medovaya skazka distinguished itself with the highest yield. In 2021, the yield for the Medovaya Skazka variety was 64.7 t/ha. The yield increase was obtained due to an increase in fruit weight, which in 2020 amounted to 2.9 kg, in 2021 - 6.5 kg. The studied varieties of pumpkin differed in quality indicators of fruits. On average, over two years, the varieties Rossiyanka and Mramornaya showed an increase in the content of water-soluble sugars in fruits. The fruits of the pumpkin Candied fruit and Kroshka were distinguished by a high content of dry matter.

Solanum carolinense L.

<i>Solanum carolinense</i> L.

Responses of Soybean to Selected Abiotic Stresses—Photoperiod, Temperature and Water

The sharp increase in soybean (Glycine max (L.) Merrill) acreage in the late 20th century and early 21st century is due to the demand for edible oil and feed protein. However, a limiting factor in the extent of soybean cultivation is its high heat requirements and response to photoperiod. Most varieties are short-day plants and are generally the best-yielding genotypes. At higher latitudes (longer day length), there is a delay in the occurrence of subsequent developmental stages and problems with plant maturation before the onset of autumn frost. Global warming allows the cultivation range of warm-season species (including soya) to be shifted; however, periodic droughts and very high temperatures limit crop production. Adverse weather events result in a reduction in soybean seed yield of around 30%. Environmental stresses related to day length, high and low temperatures and water shortage or excess have the greatest impact on soybean yields, as we have no influence on them and can only, to a very limited extent, offset their negative effects. This paper reviews the recent world literature on how soybean responds to these stress factors. The results of our own research were also used.

PROSPECTS OF SOYBEAN GROWING IN THE WESTERN POLISSIA ZONE

Modern climatic changes, namely significant warming in the northern Forest-Steppe and Polissia zones of Ukraine, provide opportunities for growing a number of grain and leguminous crops (maize for grain, soybeans, sunflower, and others), previously unusual for this region. Among the above-mentioned crops, soybean is a crop that can significantly improve the nitrogen balance of the soil without the use of mineral fertilizers; its cultivation to some extent can be an alternative to expensive nitrogen fertilizers because, under the condition of inoculation, soybean can leave up to 80 kg/ha of biological nitrogen, which equivalent to 300 kg of ammonium nitrate, which is enough for forming decent harvest of winter wheat or corn. The analysis of meteorological data shows that when having the current amount of heat supply during the growing season in the Western Polissia zone, it is possible to grow ultra-early and early-ripening soybean varieties with a duration of the growing season of up to 90-100 days and a required number of heat units - up to 2400-2500 CHU. It was established that the main factor limiting the cultivation of soybeans on the peat soils of the Western Polissia zone is a significantly shorter frost-free period (compared to the adjacent sod-podzolic soils on dry land). Therefore, for growing on peat soils, it is necessary to choose ultra-early varieties of soybeans with a growing season of up to 85 days and the required number of heat units - up to 2400-2500 CHU. That will allow obtaining physiologically ripe seeds before the onset of the first autumn frosts, which in some years can already occur in the first decade of September. On peat soils, the yield of the Yunka soybean variety by the variants of the experiment ranged from 15,1-24,8 t/ha, while on the adjacent sod-podzolic light loamy soils it was 30,3-46,8 t/ha. The reason for the significantly lower soybean yield on peat soils is a short frost-free period compared to sod-podzolic soils, which did not allow the studied varieties to fully realize their potential for 2 years in a row. The research has established that on sod-podzolic light loamy soils of the Western Polissia zone, under favorable conditions, the yield of such ultra-early and early-ripening soybean varieties as Yunka and Astor of the Sevita genetics selection (Canada) can be up to 45,0-46,8 t/ha. The use of Rizofix inoculant in a combination with Rice Pi phosphorus-mobilizing product allows increasing the productivity of soybeans to 6,7-7,0 t/ha. Additional profit from their use is about 8-8,3 thousand hryvnias from 1 ha.

Frost Conditions Due to Climate Change in South-Eastern Europe via a High-Spatiotemporal-Resolution Dataset

Frost incidents comprise significant extreme weather events owing to climate change, possibly endangering the agricultural sector of the already impacted south-eastern European area. Thus, the comprehensive evaluation of the frost conditions under the climate regime for eleven countries was conducted by calculating relevant frost agroclimatic indicators under three time horizons (1985 to 2015, 2005 to 2035 and 2015 to 2045). The Frost Days (FD), Free of Frost Days (FFD), Last Spring Frost (LSF) and First Autumn Frost (FAF) were estimated daily over a grid of 25 × 25 km. We demonstrated that the FD will be reduced according to the balanced A1B emissions scenario over the entire examined area with the mountainous and continental regions being most affected. From 2005 to 2035, a higher LSF reduction is expected over Greece and Albania and the earlier FAF in high altitude areas. All examined regions are projected to face delayed FAF, from 2015 to 2045. In general, all countries will face an increase in the growing season duration owing to the increase of the FFD.

Delayed autumnal leaf senescence following nutrient fertilization results in altered nitrogen resorption.

Increased atmospheric nitrogen (N) deposition could create an imbalance between N and phosphorus (P), which may substantially impact ecosystem functioning. Changes in autumnal phenology (i.e., leaf senescence) and associated leaf nutrient resorption may profoundly impact plant fitness and productivity. However, we know little about how and to what extent nutrient addition affects leaf senescence in tree species, or how changes in senescence may influence resorption. We thus investigated the impacts of N and P addition on leaf senescence and leaf N resorption in 2-year-old larch (Larix principisrupprechtii) seedlings in northern China. Results showed that nutrient addition (i.e., N, P or N+P addition) significantly delayed autumnal leaf senescence, and decreased leaf N resorption efficiency (NRE) and proficiency (NRP), particularly in the N and N+P treatments. Improved leaf N concentrations were correlated with delayed leaf senescence, as indicated by the positive relationship between mature leaf N concentrations and the timing of leaf senescence. Following nutrient addition, larch seedlings shifted toward delayed onset, but more rapid, leaf senescence. Additionally, we observed an initial negative correlation between the timing of leaf senescence and NRE and NRP, followed by a positive correlation, indicating delayed and less efficient remobilization during the early stages of senescence, followed by accelerated resorption in the later stages. However, the latter effect was potentially impaired by the increased risk of early autumn frost damage, thus failed to fully compensate for the negative effects observed during the early stages of senescence. Improved soil P availability increased leaf N resorption and thus weakened the negative impact of delayed leaf senescence on leaf N resorption, so P addition had no significant impact on leaf N resorption. Overall, our findings clarify the relationship between nutrient addition-resorption and the linkage with leaf senescence, and would have important implications for plant nutrient conservation strategy and nutrient cycling.

ECOLOGICAL AND GEOGRAPHICAL ANALYSIS OF DISTRIBUTION OF &lt;i&gt;HERACLEUM PERSICUM&lt;/i&gt;, &lt;i&gt;H. MANTEGAZZIANUM&lt;/i&gt; AND &lt;i&gt;H. SOSNOWSKYI&lt;/i&gt; ON THE NORTHERN LIMIT OF ITS SECONDARY RANGE IN EUROPE

The group of plants known as giant hogweeds: , and are widely recognized as dangerous alien species in Europe. We have analyzed the climatic conditions on the northern boundary of the secondary range of giant hogweeds group species in Northern Europe. The northernmost areas of growth of H. persicum are localized in the coastal regions of the northern and central parts of the Scandinavian Peninsula (up to 71° NL). Within Fennoscandia, the plants and were found up to 69° NL. The natural gradient of climatic parameters within the subarctic and temperate zones in Northern Europe allowed us to assess the ranges of climatic conditions required for the plants in this territory. We have found that the minimum sum of active temperatures values required for these alien plants are &gt;1150 °С (for temperatures above 5 °C) and &gt;450 °С (for temperatures above 10 °C). The heat resource exceeding this level ensures successful growth, development and reproduction of giant hogweeds group species in the climatic conditions of Subarctic Europe. The presence of stable snow cover on the territories with very low air temperatures during winter period prevents buds and seedlings cold damage. Climatic indices calculated as ratio of air temperature and snow depth or winter precipitation can serve as markers reflecting climatic constraints for the expansion of alien giant hogweeds group species in north direction. The main climatic parameters limiting the distribution of these species in Northern Europe are: insufficient sum of active temperatures, seasonal freezing of soils to temperatures critical for wintering organs of plants, late spring and early autumn frosts.

Многогодишна изменчивост и тренд на характеристиките на безмразовия период над Централна и Югоизточна Европа през 1950-2019

Agriculture and forestry are two economic sectors most dependent on climate, and climate change has a direct and indirect impact on biotic and abiotic disturbances with strong implications. The air temperature is one of the major environmental factors affecting growth, development, and yields of crops. Despite the undeniable global warming, damage to crops by frost and freezing temperatures causes serious loss to farmers in many parts of the world. The frost-free season has a large influence on plant phenology, with implications for the distribution of natural vegetation and the types of crops grown in a particular region. The present study is dedicated to the climatology of the frost-free season over Central and Southeast Europe in the second half of the previous and the first two decades of this century. The climatology of the frost-free season is characterized by three indicators, namely the date of the last spring frost, the date of the first autumn frost, and the length of the frost-free season. Additionally, the middle date of the frost-free season as measure of the seasonal shift is analysed. The study, which is performed for the thresholds of -2.2 °C and 0 °C, reveals non-negligible lengthening of the frost-free season, associated primarily with an earlier date of last spring frost rather than a delayed date of first autumn frost.