Duration Of Growing Season Research Articles

Eligibility criteria for joint ensilage of maize and yellow lupine on poorly productive lands of the Upper Volga region

In the modern conditions of RF agro-industrial complex development, the transfer of animal husbandry to an industrial basis is possible only with high-grade vegetable protein production increase. Silage of the aboveground mass of pure corn during all phases of plant growth and development does not provide the content of nutrients in the feed unit according to the zootechnical requirements. Therefore, to optimize the finished feed in terms of the carbohydrate-protein ratio, green mass of legumes should be added to its composition during the preparation of silage from corn. The selection of the legume component should be carried out taking into account the following main criteria: coincidence with corn by the growing season duration, the same attitude to soil and climatic resources and insolation conditions, high provision of the legume component with digestible protein, dry matter, starch and exchange energy during the ensiling period. It has been established that the joint ensiling of corn with yellow lupine is expedient when the corn is in waxy ripeness, and the lupine is in the phase of shiny beans with the component ratio of 55:45%. In this case, the content of digestible protein in 1 feed unit of finished silage is 100.2 g at reliable feed supply with both irreplaceable (36.0 g) and critical (7.2 g) amino acids.

Impact of climatic patterns on phenophase and growth of multi-purpose trees of north-western mid-Himalayan ecosystem

Earth's mean air temperature is increasing at an accelerating rate, and forest tree species are sensitive to this changing climate. However, tree species react variably to changing climates across different geographical ranges. Thus, eleven multi-purpose tree species (MPTs), Albizia stipulata, Bauhinia variegata, Celtis australis, Dalbergia sissoo, Gmelina arborea, Grewia optiva, Melia azedarach, Morus alba, Robinia pseudoacacia, Sapindus mukorossi and Toona ciliata, of the mid-hill zone of the northwestern Himalayas were selected to analyze the impact of climatic patterns on their phenological events over two decades (1999–2017). The results indicated that phenological advancement (in days) was more pronounced from 1999 to 2006 than from 2006 to 2017. Specifically, leaf emergence phase advancement ranged from 5 (R. pseudoacacia) to 38 days (M. alba). However, advancement in the flower initiation phase for MPTs was not as prominent. The growth period of M. azedarach was prolonged the most (60 days), followed by those of B. variegata (56 days), D. sissoo (51 days), T. ciliata (48 days), S. mukorossi (46 days), R. pseudoacacia (44 days), G. optiva (41 days), G. arborea (20 days), A. stipulate (15 days), M. alba (10 days) and C. australis (7 days). Increasing growing season duration and rate have implications on future composition, nutrient cycling and carbon sequestration of agro-ecosystems of the mid-hill zone of the north western Himalayas.

Adaptive phenological response of grape varieties orientalis C. Negr. on changes in weather and climatic conditions in the south of Russia

The studies were carried out in the temperate continental climate of southern Russia in the plantations of the Anapa ampelographic collection on the varieties Adisi, Kuldzhinsky, Tarnau belonging to the group orientalis C. Negr. It was found that the growing season duration of Adisi variety from budding to the full physiological maturity of grape berries decreased by 24 days, of Kuldzhinsky variety - by 23 days, of Tarnau variety - by 27 days. Regularities have been established that indicate a close and average positive correlation relationship between a decrease in the duration of the growing season and an increase in the sum of active air temperatures.

Growing faster, longer or both? Modelling plastic response of Juniperus communis growth phenology to climate change

AbstractAimPlant growth and phenology respond plastically to changing climatic conditions in both space and time. Species‐specific levels of growth plasticity determine biogeographical patterns and the adaptive capacity of species to climate change. However, a direct assessment of spatial and temporal variability in radial growth dynamics is complicated, because long records of cambial phenology do not exist.LocationSixteen sites across European distribution margins of Juniperus communis L. (the Mediterranean, the Arctic, the Alps and the Urals).Time period1940–2016.Major taxa studiedJuniperus communis.MethodsWe applied the Vaganov–Shashkin process‐based model of wood formation to estimate trends in growing season duration and growth kinetics since 1940. We assumed that J. communis would exhibit spatially and temporally variable growth patterns reflecting local climatic conditions.ResultsOur simulations indicate regional differences in growth dynamics and plastic responses to climate warming. The mean growing season duration is the longest at Mediterranean sites and, recently, there has been a significant trend towards its extension of up to 0.44 days/year. However, this stimulating effect of a longer growing season is counteracted by declining summer growth rates caused by amplified drought stress. Consequently, overall trends in simulated ring widths are marginal in the Mediterranean. In contrast, durations of growing seasons in the Arctic show lower and mostly non‐significant trends. However, spring and summer growth rates follow increasing temperatures, leading to a growth increase of up to 0.32 %/year.Main conclusionsThis study highlights the plasticity in growth phenology of widely distributed shrubs to climate warming: an earlier onset of cambial activity that offsets the negative effects of summer droughts in the Mediterranean and, conversely, an intensification of growth rates during the short growing seasons in the Arctic. Such plastic growth responsiveness allows woody plants to adapt to the local pace of climate change.

Present-day breeding of legumes and groat crops in Russia.

The production of pedigree seeds is not only an important but also a cost-effective means of increasing the yield and efficiency of agriculture. The genetic potential of varieties can be unlocked only by choosing those adaptive to the soil and climatic conditions in a particular region, using modern tools for plant protection, and applying balanced mineral nutrition. These are the most important factors determining the performance. In the course of breeding and genetic work, the Federal Scientific Center of Legumes and Groat Crops (FSC LGC) has created new soybean varieties, whose high biological and economic potentials are combined with resistance to stress factors. Despite the close relationship between productivity and growing season duration, the highly productive and early-ripening (100–115 days) soybean varieties raised at FSC LGC can yield 2.5 to 3.5 t/ha, the grain having high contents of protein (37–42 %) and fat (18–22 %), depending on the climatic conditions in a particular year of cultivation. They are less temperature-sensitive than other domestic or foreign varieties. It is important that our soybean varieties are not genetically modified. New pea varieties created at FSC LGC in 2015–2020 differ in growing season duration and morphological features. They are adaptable to the soil and climatic conditions of a region, which ensures the maximum realization of their potential. The main factor in increasing yields and stabilizing the production of buckwheat and millet grain in the Russian Federation is the creation and adaption of new earlyripening and high-yielding varieties of the determinate type adapted to the specific natural and climatic conditions of different regions of Russia.

Biochemical composition and nutritional value of Leymus chinensis (Trin.) Tzvel. in eastern Transbaikalia

The article objective is to define the biochemical composition of Leymus chinensis (Trin.) Tzvel., its nutritional and energy value in the southern steppe zone of eastern Transbaikalia, growing in different soil and environmental conditions due to the lack of such data. The authors use standard biochemical methods to determine nutrients calculated by assessing the nutritional value and energy of plant forage. Statistical data processing is carried out in Microsoft Excel. The paper examines content of crude protein, sugars, crude fat, crude cellulose, nitrogen-free extractives, feed units and metabolizable energy in dry matter of Leymus chinensis for the first time. The study ascertains a definite relation of the nutrient accumulation, and soil and environmental conditions, growing season duration, plant development phase, and the species adaptation to prolonged aridization, which causes its vegetative reproduction due to a decrease in generative reproduction. It reveals protein ratios as an indicator of forage digestibility. The research found that the amount of both digestible nutrients, and the content of energy and metabolic energy in the forage varied in a rather narrow range, which is associated with the short growing season of Leymus chinensis development under the harsh continental climate of the steppe zone in eastern Transbaikalia.

The divergent impact of phenology change on the productivity of alpine grassland due to different timing of drought on the Tibetan Plateau

AbstractDroughts are predicted to become more frequent and persist for longer periods in the future, especially in alpine regions due to climate change. However, the association mechanism between plant productivity response to drought timing and phenology in the alpine grassland of the Tibetan Plateau is unclear. We conducted manipulative drought experiments on early growing season drought (ED) and middle growing season drought (MD) to determine the impacts of drought timing on the alpine grassland. The results showed ED significantly delayed the green‐up of the community vegetation (8.20%, p < .05). However, MD advanced the withered date of the community vegetation (−2.98%, p < .05). ED and MD depressed the growing season duration, cover, height, and the aboveground biomass of the community vegetation. However, the structural equation model revealed that the effect of phenology changes on the aboveground net primary production shifts was divergent among graminoid, weeds, and community. Our results shed light on the drought tolerance mechanisms of diverse vegetation groups at different drought timings. Thus, the drought timing should not be neglected in climate change studies, especially in research related to climate extremes.

Evaluation of durum winter wheat varieties by growth and development indicators

The article presents the study results of the formation of growth and development indicators (growing season length of plants, plant height, density dynamics, ear parameters and grain yield) of domestic varieties of durum winter wheat. It is analyzed that the level of the signs manifestation varies signifcantly depending on the weather conditions of the growing season. However, the growing season duration hardly depend on weather conditions and is 268–269 days. In the full ripeness stage, the height of plants increased 1.4–1.8 times in comparison with earing with insignifcant variation (V=1–5 %) depending on the variety. The lowest plants were Athena, Continent and Laguna – 71–76 cm. Uneven precipitation distribution and high air temperature in 2013 contributed to the formation of fewer stems of durum winter wheat plants compared to more favourable 2014. In the full ripeness stage of durum winter wheat grain in 2013, the coefcient of total tillering was 1.01–1.26 depending on the variety. In 2014, the stem density was the highest. In the full ripeness stage of grain, the number of stems ranged from 650 to 812 pcs/m2 depending on the variety with a total tillering rate of 1.54–1.91. It should be noted that Athena and Linkor varieties retained a higher ability to tillering and stem survival in different weather conditions. The ear length of winter durum wheat varied from 5.9 to 6.7 cm depending on the variety with slight and small variation (V=3–16 %). The number of spikelets in the ear was from 16 to 20 pcs with a small variation coefcient. The ear length of durum winter wheat varied most. Thus, of the nine varieties, the variation coefcient of this indicator in six varieties was average, and in the rest of them - small. However, there was no signifcant difference between the varieties. The highest yields were formed by Argonaut, Gardemaryn and Linkor varieties – 6.00–6.31 t/ha or 13–19 % more than the standard. Grain yield varied signifcantly depending on the weather conditions of the growing season, which is also evidenced by the stability index and was below 1 (0.48–0.64). Less favourable weather conditions in 2013 provided the yield of 3.74–4.63 t/ha depending on the variety. More favourable weather conditions in 2014 provided the grain yield of 5.46–8.25 t/ha depending on durum winter wheat variety. It is obvious that the positive effect of weather conditions in 2014 on tillering and stem survival of winter durum wheat determined the formation of higher grain yield. Key words: durum winter wheat, variety, growth and development indicators, yield.

Climate Change, Ecosystem Processes and Biological Diversity Responses in High Elevation Communities

The populations, species, and communities in high elevation mountainous regions at or above tree line are being impacted by the changing climate. Mountain systems have been recognized as both resilient and extremely threatened by climate change, requiring a more nuanced understanding of potential trajectories of the biotic communities. For high elevation systems in particular, we need to consider how the interactions among climate drivers and topography currently structure the diversity, species composition, and life-history strategies of these communities. Further, predicting biotic responses to changing climate requires knowledge of intra- and inter-specific climate associations within the context of topographically heterogenous landscapes. Changes in temperature, snow, and rain characteristics at regional scales are amplified or attenuated by slope, aspect, and wind patterns occurring at local scales that are often under a hectare or even a meter in extent. Community assemblages are structured by the soil moisture and growing season duration at these local sites, and directional climate change has the potential to alter these two drivers together, independently, or in opposition to one another due to local, intervening variables. Changes threaten species whose water and growing season duration requirements are locally extirpated or species who may be outcompeted by nearby faster-growing, warmer/drier adapted species. However, barring non-analogue climate conditions, species may also be able to more easily track required resource regimes in topographically heterogenous landscapes. New species arrivals composed of competitors, predators and pathogens can further mediate the direct impacts of the changing climate. Plants are moving uphill, demonstrating primary succession with the emergence of new habitats from snow and rock, but these shifts are constrained over the short term by soil limitations and microbes and ultimately by the lack of colonizable terrestrial surfaces. Meanwhile, both subalpine herbaceous and woody species pose threats to more cold-adapted species. Overall, the multiple interacting direct and indirect effects of the changing climate on high elevation systems may lead to multiple potential trajectories for these systems.

Evaluation of long-term climate change impact on the growing season and water use of mature pecan in Lower Rio Grande Valley

Pecan is a major crop in the Lower Rio Grande Valley (LRGV), New Mexico. New Mexico is currently the largest pecan producer in the United States. Pecan is also considered a major water user which can consume as much as 1200–1300 mm of water during the growing season. Climate change can have significant potential impact on the water requirement of pecan as well as its productivity and cost of production. This study evaluates the climate change effects on the duration of growing season (DGS) and water requirement of pecan in LRGV over the period of 1901–2019. Temperature data for the study period was used to identify the DGS. Hargreaves–Samani model was used to calculate reference evapotranspiration (ET0). Daily crop coefficient (Kc) over the study period was calculated using a developed regression model relating growing season Kc to cumulative growing degree days (GDD). The Mann-Kendall and Sen’s methods were applied to determine if there was a significant positive or negative trend in the DGS, ET0, and actual evapotranspiration (ETa). Statistical results showed a decreasing trend in the DGS over 1901–1950 whereas an increasing trend in the DGS was detected for the period of 1950–2019. Like the DGS variations, decreasing and increasing trends for both seasonal ET0 and ETa were observed for the first 50 years and the rest of the period with 99% confidence level, respectively. Results showed an increase of 124 mm in seasonal ETa between 1950 and 2019. The study showed that climate change effects in LRGV have been occurring for the study period, continuous increases in both DGS and ETa may bring changes in crop water requirement, and economics of pecan production as well as other horticultural challenges such as insufficient chill period for flowering, increased vivipary, and delayed or prolonged harvest.

Forward Modeling Reveals Multidecadal Trends in Cambial Kinetics and Phenology at Treeline

Significant alterations of cambial activity might be expected due to climate warming, leading to growing season extension and higher growth rates especially in cold-limited forests. However, assessment of climate-change-driven trends in intra-annual wood formation suffers from the lack of direct observations with a timespan exceeding a few years. We used the Vaganov-Shashkin process-based model to: (i) simulate daily resolved numbers of cambial and differentiating cells; and (ii) develop chronologies of the onset and termination of specific phases of cambial phenology during 1961–2017. We also determined the dominant climatic factor limiting cambial activity for each day. To asses intra-annual model validity, we used 8 years of direct xylogenesis monitoring from the treeline region of the Krkonoše Mts. (Czechia). The model exhibits high validity in case of spring phenological phases and a seasonal dynamics of tracheid production, but its precision declines for estimates of autumn phenological phases and growing season duration. The simulations reveal an increasing trend in the number of tracheids produced by cambium each year by 0.42 cells/year. Spring phenological phases (onset of cambial cell growth and tracheid enlargement) show significant shifts toward earlier occurrence in the year (for 0.28–0.34 days/year). In addition, there is a significant increase in simulated growth rates during entire growing season associated with the intra-annual redistribution of the dominant climatic controls over cambial activity. Results suggest that higher growth rates at treeline are driven by (i) temperature-stimulated intensification of spring cambial kinetics, and (ii) decoupling of summer growth rates from the limiting effect of low summer temperature due to higher frequency of climatically optimal days. Our results highlight that the cambial kinetics stimulation by increasing spring and summer temperatures and shifting spring phenology determine the recent growth trends of treeline ecosystems. Redistribution of individual climatic factors controlling cambial activity during the growing season questions the temporal stability of climatic signal of cold forest chronologies under ongoing climate change.

БОБОВЫЕ ПРЕДШЕСТВЕННИКИ, ОБРАБОТКА ПОЧВЫ И ЗАЩИТА РАСТЕНИЙ В АГРОТЕХНОЛОГИЯХ ЯРОВОЙ ПШЕНИЦЫ СРЕДНЕГО ПОВОЛЖЬЯ

The article presents the results of studies on the evaluation of legume precursors (soybeans, peas, lupin, chickpeas), methods of primary tillage, and plant protection during spring wheat cultivation in the conditions of chernozem soils of the Middle Volga region. Studies have shown that the studied precursors had different growing season duration and water consumption, which provided different water regimes and accumulation of productive moisture in the soil and ultimately affected the productivity of spring wheat. The accumulation of productive moisture in the soil occurs mainly in the autumn, winter, and spring periods; after harvesting peas, no more than 19% of precipitation (28–33 mm) accumulated after harvesting soybeans,lupine, and chickpeas – 29–39% (29–39 mm) until the time of a steady transition of air temperature below 5оC. According to the yield level of spring wheat, the researchers arranged the studied precursors in the following row: after peas – 3,80 t/ha > after chickpeas and lupine – 3,49–3,50 t/ha > after soybeans – 3,45 t/ha. There was an increase in the yield of spring wheat for combined tillage in crop rotation (for the studied crop – soil disking by 10–12 cm + plowing by 20–22 cm) in comparison with minimal tillage by 0,52 t/ha or by 15,6%, and on adaptiveintegrated plant protection by 0,36 t/ha or 10,6% in comparison with the level of standard technologies.The effect of the studied factors on the formation of yield was as follows: tillage – 40,7% > plant protection – 25,3% > precursors – 19,1%. The mentioned variants also increased the quality of spring wheat grain.

Influence of planting dates on corn hybrids growing season duration

Influence of planting dates on corn hybrids growing season duration

Economic and biological assessment of Tartary buckwheat variety ‘Kalyna’

Purpose. To evaluate Tartary buckwheat variety ‘Kalyna’ according to morphological, productive and quality indicators in the conditions of the Research Center “State Agra­rian and Engineering University in Podilia”. Methods. The studies were carried out in the field crop rotation of the Research Center “Podillia” of the State Agrarian and Engi­neering University in Podilia (SAEU) in 2015–2020. The soil cover of the experimental field is represented mainly by low-humus, weakly leached soils. Experiment setting, material evaluation, analysis of plants, yield and grain quality were carried out in accordance with the generally accepted methods of state variety testing. An assessment of the Tartary buckwheat variety ‘Kalyna’ was carried out in comparison with the common buckwheat variety ‘Victoriia’. Results. The growing season duration of Tartary buckwheat variety ‘Kalyna’ was 87 days (38 days vegetative and 49 days gene­rative). In the studied variety, a larger number of the 1st order branches up to 5.5 pcs was observed. The number of leaves on the plant was 22–28 pcs./plants. In the studied variety, more than 50% of the grains were located on the main stem and the first order branches, while in common buckwheat this indicator was only 30%. Productivity was 2,28 t/ha, the number of grains in inflorescences was 4,4 grains, in common buckwheat – 0,72 t/ha, and 2.2 grains/inflorescence, respectively. The thousand kernel weight in Tartary buckwheat variety ‘Kalyna’ is 10.2 g less than in common buckwheat variety ‘Victoriia’ and is 17.4 g, with hulls – 19.5%, which is 3.2% less then in common buckwheat variety.Assessment of Tartary buckwheat variety ‘Kalyna’ for resistance to the effects of bio- and abiotic factors indicates that it was at the level of common buckwheat variety ‘Victoriia’.In terms of resistance to abiotic factors, ‘Kalyna’ variety is characterized by high resistance to spontaneous fallof grain (5 scores) and has simultaneous grain ripening (5 scores). Conclusions.The morphological and economic-biological indicators of Tartary buckwheat variety ‘Kalyna’ are significantly higher than the common buckwheat varie­ty ‘Victoriia’. It is recommended to grow Tartary buckwheat variety ‘Kalyna’ as a valuable cereal crop in the Western Forest-Steppe zone.

Evaluation of Different Crop Models for Simulating Rice Development and Yield in the U.S. Mississippi Delta

The United States is one of the top rice exporters in the world, but warming temperatures and other climate trends may affect grain yield and quality. The use of crop models as decision support tools for a climate impact assessment would be beneficial, but suitability of models for representative growing conditions need to be verified. Therefore, the ability of CERES-Rice and ORYZA crop models to predict rice yield and growing season duration in the Mississippi Delta region was assessed for two widely-grown varieties using a 34-year database. CERES-Rice simulated growth duration more accurately than ORYZA as a result of the latter model’s use of lower cardinal temperatures. An increase in base and optimal temperatures improved ORYZA accuracy and reduced systematic error (e.g., correlation coefficient increased by 0.03–0.27 and root mean square error decreased by 0.3–1.9 days). Both models subsequently showed acceptable skill in reproducing the growing season duration and had similar performance for predicting rice yield for most locations and years. CERES-Rice predictions were more sensitive to years with lower solar radiation, but neither model accurately mimicked negative impacts of very warm or cold temperatures. Both models were shown to reproduce 50% percentile yield trends of more than 100 varieties in the region for the 34-year period when calibrated with two representative cultivars. These results suggest that both models are suitable for exploring the general response of multiple rice cultivars in the Mississippi Delta region for decision support studies involving the current climate. The response of rice growth and development to cold injury and high temperature stress, and variation in cultivar sensitivity, should be further developed and tested for improved decision making tools.

GIS-Based Land Suitability and Crop Vulnerability Assessment under Climate Change in Chtouka Ait Baha, Morocco

Agriculture plays a crucial role in the economic development in Morocco, contributing to 14% of the national gross domestic product. However, this sector is facing various challenges, including climate change. This study aims to assess relevant indicators that may affect land suitability, water demand, and crop growing season duration under climate change. Further, it may be used as a decision support tool in the Chtouka area known for its irrigated agriculture. The approach proposed, the spatial distribution of land based on suitability, is founded on the multiple-criteria decision-making method of four parameters; soil texture, temperature, land use, and slope. The duration of the length of crop season was simulated using the concept of growing degree days. The projection of land suitability for 2031–2050 indicated an important decrease of 12.11% of “highly suitable” agricultural land under the RCP4.5 emission scenario and a significant increase of 4.68% of “highly unsuitable” land, according to the RCP8.5 emission scenario compared to the baseline (1985–2005). The projected growing degree days in 2031–2050 showed a strong shortening in the growing period length compared to the baseline 1985–2006, mainly under the RCP8.5 emission scenario, with a reduction from 8% to 21% depending on crops. Moreover, crop water productivity indicated that berries were over 50% less water productive than other vegetable crops for almost the same amount of applied irrigation water. These findings highlight the vulnerability of agriculture to climate change, which requires important political and management efforts to sustain agricultural activity.

Agronomic performance of the lignocellulosic feedstock crop energy cane in the Texas Rolling Plains

AbstractFeedstock genetics and environment are important factors determining biomass yield of biofuel crops. Field studies were conducted to evaluate agronomic performance of four energy cane (Saccharum spp. hybrid) genotypes (TUS11‐62, TUS11‐58, TCP10‐4928, and Ho 02‐113) in the Texas Rolling Plains. In the first study, cane billets were planted in 2015 and data were collected from first (2016) and second (2017) ratoons. A second study was planted in 2016 and data were collected the same year from plant cane. Data collected include biomass, stalk height, stalk population, leaf area index (LAI), and normalized difference vegetation index (NDVI). Biomass yield of ratoons was not significantly different (p > .05) among genotypes. However, TUS11‐58 had the highest plant cane yield. The average biomass yield of plant cane, first, and second ratoons were 20.2, 40.4, and 26.4 t ha−1 respectively. Longer growing period of ratoon (∼8 mo) compared to plant cane (∼5.5 mo) increased biomass. However, low temperatures (−14 to −16 °C) during the dormant phase resulted in lower yield of the second ratoon. Among genotypes, TUS11‐62 had taller stalks, but was cold sensitive. Genotype TCP10‐4928 had higher stalk population and LAI. An exponential relationship was observed between LAI and NDVI (R2 = .67). Overall, there were differences in growth characteristics of energy cane genotypes, however biomass yield was similar in the ratoon phase. The results of this study showed that low temperature tolerance and growing season duration are key factors in determining biomass yield in higher latitude regions such as the Texas Rolling Plains.

Impacts of 1.5 °C and 2.0 °C global warming above pre-industrial on potential winter wheat production of China

Abstract Keeping global temperatures below 2.0 °C above pre-industrial condition and pursuing efforts toward the more ambitious 1.5 °C goal in the late 21st century was the main target from the Paris Agreement in 2015. Here we assessed the likely challenges for the China’s winter wheat production under 1.5 °C and 2.0 °C increase of global temperature, with four wheat crop models (CERES-Wheat, Nwheat, WheatGrow, and APSIM-Wheat) and the latest climate projections from the Half a degree Additional warming, Prognosis and Projected Impacts project (HAPPI). Instead of using average “winter type” wheat cultivar, and same management and soil inputs for whole region, location-specific winter wheat cultivars with local agronomic information were calibrated for each of the representative wheat growing area of China, allowing a better spatial agronomic representation of the whole wheat planting area. The mean growing season temperature (GST) during the winter wheat vegetative stage was projected to increase by 0.6 to 1.4 °C for the 1.5 °C scenario, and 0.9 to 1.8 °C for the 2.0 °C scenario, while during the reproductive stage was decreased between 0 and 0.9 °C for the 1.5 °C scenario and -0.3 and 1.1 °C for the 2.0 °C scenario. Growing season duration (GSD) for the whole period was shortened by 6 to 15 days for the 1.5 °C scenario and 8 to 18 days for the 2.0 °C scenario, as a result of higher GST under global warming. Increase in GST and decrease in GSD was more obvious in the Southwest Subregion (SWS) than subregions in the north. The shortening GSD for the whole wheat growth period was mostly from the shortening vegetative period, as no appreciable difference in number of days from anthesis to maturity was found for the whole regions. Although there is variability among models, the indication is that wheat yields were projected to increase in the North Subregion (NS), the Huang-Huai Subregion (HHS), and the Middle-lower Researches of Yangzi River Subregion (MYS), but to decrease in the SWS under two warming scenarios. The effects of elevated CO2 concentration were mostly beneficial and tended to offset the negative impacts of increasing temperature at both global warming scenarios, with a rate of 7-14% yield increase per 100-ppm, except for locations with GST of baseline higher than 11 °C. Aggregating to regional wheat production, the total winter wheat production of China was projected to increase by 2.8% (1.6% to 3.0%, 25th percentile to 75th percentile) and 8.3% (7.0% to 9.6%, 25th percentile to 75th percentile) under 1.5 °C and 2.0 °C scenarios, and most of increase was observed in the north subregions due to the largest wheat planting area. Our results will lay the foundation for developing adaptation strategies to future climate change to ensure China and global wheat supply and food security.

Peatland warming strongly increases fine-root growth

Belowground climate change responses remain a key unknown in the Earth system. Plant fine-root response is especially important to understand because fine roots respond quickly to environmental change, are responsible for nutrient and water uptake, and influence carbon cycling. However, fine-root responses to climate change are poorly constrained, especially in northern peatlands, which contain up to two-thirds of the world's soil carbon. We present fine-root responses to warming between +2 °C and 9 °C above ambient conditions in a whole-ecosystem peatland experiment. Warming strongly increased fine-root growth by over an order of magnitude in the warmest treatment, with stronger responses in shrubs than in trees or graminoids. In the first year of treatment, the control (+0 °C) shrub fine-root growth of 0.9 km m-2 y-1 increased linearly by 1.2 km m-2 y-1 (130%) for every degree increase in soil temperature. An extended belowground growing season accounted for 20% of this dramatic increase. In the second growing season of treatment, the shrub warming response rate increased to 2.54 km m-2 °C-1 Soil moisture was negatively correlated with fine-root growth, highlighting that drying of these typically water-saturated ecosystems can fuel a surprising burst in shrub belowground productivity, one possible mechanism explaining the "shrubification" of northern peatlands in response to global change. This previously unrecognized mechanism sheds light on how peatland fine-root response to warming and drying could be strong and rapid, with consequences for the belowground growing season duration, microtopography, vegetation composition, and ultimately, carbon function of these globally relevant carbon sinks.

Study of Initial Material of Vetch

The study was conducted in the experimental field of the Institute of Forage Crops – Pleven, Bulgaria for a three-year period. Ten vetch specimens (varieties and populations) different originated were examined – Bulgarian population (Vicia sativa); Bulgarian population (Vicia pannonica ssp. striata; Detenicka Panonska (Vicia pannonica) and Asko 1; Kowatschite, K- 25 331, K- 29 800, K- 30 553, K- 30 574, K- 30 671 from Vicia villosa. The main quantitative characteristics were analyzed: plant height (cm), height of the first pod (cm), number of pods per plant, number of seeds per plant, number of seeds per pod, weight of seeds per plant (g) and indicators: beginning of flowering stage (days) and duration of the growing season (days). Two-way ANOVA and variance analysis were used for statistical data processing. High values ​​of variation coefficient were found for seed weight (107.87%), number of seeds per plant (88.80%), height of first pod (30.78%), number of pods per plant (37.97%) and number of seeds per pod (27.45), and average variation for plant height (15.97%), respectively. The varieties of Vicia pannonica can be characterized as early ripening with a growing season duration of 244-246 days, the population of Vicia sativa as medium ripening (242-252 days), and from Vicia villosa (except K-29 800, Kowatschite and Asko 1) as late maturing (242-256 days). The varieties of the species Vicia villosa K-30 671, Asko and 1 K-25 331, which are well leafed and form long stems (142-151 cm), are suitable as parental components in the combinational selection in the direction for forage. The Bulgarian population of Vicia sativa was found to form the largest number of both, pods (87) and seeds (351). For other the numbers, the seeds per plant trait was between 116 (K-30 574) and 133 (K-30 553). In the direction of seed production the Bulgarian population of Vicia sativa can be emitted.