Growing Season Conditions Research Articles

Developing Economic Injury Levels for Thrips (Frankliniella occidentalis) in Idaho Alfalfa Under Controlled Pest Populations

Thrips are a new pest of alfalfa in Eastern Idaho. University of Idaho Extension Educators studied the yield losses associated with this pest in a controlled greenhouse experiment. This data has been used to calculate the economic injury level (EIL) of thrips in alfalfa. The EIL represents the level of insect infestation at which control measures will begin to be economically viable. We calculate that for the 2021 growing season conditions the EIL was approximately 20 thrips per six stems. We also calculated EIL curves that growers and consultants can use as spray costs and hay values change.

Comprehensive evaluation of spring barley mutants according to their yield components

Background. The need to increase the genetic diversity of barley (Hordeum vulgare L.) is determined by its value and cultivation scope, which is especially important in the context of the changing climate.Material and methods. The study was carried out in 2021 and 2022 at the experimental site of the Lake Kuchak biostation located in Nizhnetavdinsky District, Tyumen Province (57°20ʼ57.3”N, 66°03ʼ21.8”E). Mutant forms were obtained by treating seeds of accessions ʻZernogradsky 813ʼ, Dz02-129 and C.I. 10995 with solutions of the chemical mutagen phosphemide at concentrations of 0.002% (2·10–3 М) and 0.01% (1·10–2 М). The mutants of the fifth (M5) and sixth (M6) generations were evaluated for a set of traits valuable for breeding in comparison with the original forms and reference cultivars ʻAchaʼ and ʻAbalakʼ. The main productivity characters were analyzed in the laboratory, and breeding indices were calculated (ear potential index, Canadian index, ear linear density index, Mexican index, plant productivity index, and Finnish-Scandinavian index).Results and conclusion. Most of the studied mutants under moisture deficit and elevated temperature conditions were superior to the original forms in their productivity characters. Mutant plant samples with stable manifestation of those traits, irrespective of the growing season conditions, were selected. Assessment of the genotype–environment interaction using breeding indices made it possible to identify promising mutants for inclusion in breeding programs. Correlation analysis helped to identify indices closely related to grain yield: Canadian index (r = 0.85), Mexican index (r = 0.76), and plant productivity index (r = 0.70). They can be recommended for selection of stress-resistant barley forms.

Accounting for age: uncovering the nuanced drivers of mammal body-size responses to climate change.

Shifts in mean body size coinciding with environmental change are well documented across animal species and populations, serving as a widespread and complex indicator of climate-change response. In mammal research, identifying and disentangling the potential drivers of these trends (e.g., thermoregulation, resource availability) is hindered by treating adult size as fixed, ignoring morphological changes that occur throughout life in many species. However, observed population-level size trends may reflect underlying shifts in age structure (i.e., change in the proportion of older, potentially larger individuals in the population). Here, we assessed the role of age structure by explicitly evaluating age as a contributor to temporal variation in skull size (a proxy for body size) in 2 carnivorans, Canadian Lynx (Lynx canadensis) and American Marten (Martes americana). Using a series of linear and nonlinear models, we tested age in years (determined by cementum-layer analysis) as a predictor of skull size alongside other factors previously proposed to be important drivers of body-size trends, including population density for lynx and growing season conditions for martens. In both species, age was a significant predictor of skull size indicating a rapid year-to-year increase in young adult size that diminished in later adulthood. However, temporal shifts in age structure alone did not explain the observed changes in size over time, indicating that age structure acts in concert with other as-yet unidentified factors to drive body-size change. By explicitly evaluating the role of age, we can both refine models of temporal body-size trends and gain insights into size change as a signal of underlying demographic shifts-such as age-specific survivorship-providing a more holistic understanding of how mammals are responding to climate change.

Response of Bread Wheat Cultivars to Terminal Water Stress and Cytokinin Application from a Grain Phenotyping Perspective

A better understanding of the responsiveness of grain phenotypic indices to terminal water stress (TWS) in wheat might help explain grain weight variations and determine which grain traits are most affected. A two-year field experiment (2020–2021 and 2021–2022) was conducted to identify how TWS and exogenous cytokinin application might affect grain weight and grain dimensions in three bread wheat cultivars using high-throughput digital image phenotyping. The results showed that the effects of growing seasons, irrigation, and cultivars were significant on grain weight and phenotypic indices. In our study, TWS significantly reduced thousand grain weight (24.62%, 14.65%) and grain development in the width directions MinFeret, i.e., minimum caliper diameter (10.70%, 6.64%) and Minor, i.e., the minor axes of the best fitted ellipses to the grains (10.91%, 6.65%), or synthesized indices including Area/Perim. (9.01%, 5.42%), Area × Circ. (17.30%, 10.13%), Minor/Solid. (10.26%, 6.32%), MinFeret/Solid. (10.01%, 6.11%), Area × Solid (13.94%, 7.96%), Perim. × Circ. (9.07%, 5.42%), A1 (29.99%, 17.09%), and A2 (30.20%, 17.27%) in each growing season, respectively. Regardless of the factors causing these variations, a sustained relationship was found between thousand grain weight and phenotypic indices, with significant positive correlations. The stronger positive correlation between thousand grain weight and grain width indices (r ≥ 0.965) showed important implications for grain development and filling. The Torabi cultivar performed better than the Sirvan and Pishgam in both growing season conditions. In addition, the technical advantages of developing phenotyping approaches, the present study could contribute to a better physiological evaluation of wheat cultivars in multivariate environments.

Перспективы применения различных органоминеральных удобрений на яровом ячмене

The results of field experiments on spring barley conducted in 2023 on the experimental fields of the Agrobiotechnopark of the Kazan State Agrarian University are presented. The purpose of the research was to assess the impact of the use of various compositions of organomineral fertilizers based on natural minerals (zeolite, diatomite, perlite), humates and food industry waste (buckwheat husk, beet molasses) developed at the Institute of Agrobiotechnologies and Land Management of Kazan State Agrarian University on the formation of the yield and grain quality of spring barley. The objectives of the research included studying the nature of changes in plant growth and development, yield and protein content in grain when using experimental organomineral fertilizers. The object of the study was spring barley of the Raushan variety. The control was the option without fertilizers; the standard was the application of 100 kg/ha of azofoska. Experimental fertilizers were applied at a rate of 120 kg/ha. All fertilizers in the experiment were applied before sowing. The studies were carried out on gray forest highly cultivated soil. The growing season conditions in 2023 were characterized by periodically severe drought phenomena, which affected the growth and development of spring barley plants. It was found that the application of experimental fertilizers contributed to the growth of the length of roots and above-ground parts of plants, and also reduced the damage to plants by root rot. Diatomite-based fertilizer had the greatest positive effect on reducing root rot damage. The largest increase in yield over the control (by 0.73 t/ha) and standard (by 0.22 t/ha) was obtained when using diatomite-based fertilizer. The use of all organomineral fertilizers (especially those based on zeolite) leads to an increase in the protein content in the grain.

FEATURES OF THE MANIFESTATION OF BIOMETRIC INDICATORS IN VARIETIES AND BREEDING LINES OF WINTER BREAD WHEAT AT SPRING RENEWAL OF VEGETATION DATE IN THE FOREST STEPPE OF UKRAINE

The growth, development, and yield formation of winter bread wheat depends on renewal of vegetation date (RVD). This is one of the environmental factors most affecting the production process of plants. Purpose. To identify the peculiarities of the manifestation of biometric indicators in the genotypes of winter bread wheat at renewal of spring vegetation date in the conditions of the central Forest-Steppe of Ukraine. Methods: field, laboratory, statistical. Results. It was established that biocenosis formation of winter wheat at renewal of spring vegetation date significantly depended on growing conditions, sowing date, genotype and their interaction. Weather conditions were the dominant (25.2÷69.5%) significant for the influence. It was determined that after renewal of spring vegetation the influence of genotype (its ability to intensive growth and adequate response to changes in environmental conditions) and its interaction with the growing season conditions on all biometric indicators significantly increased. It was noted that under favorable hydrothermal regime, the level of realization of plant potential was maximum, while under conditions of soil and air drought it was minimum. This must be taken into account in breeding process, study of the source material, and selection of genotypes with specified parameters. The breeding line LUT 55198 had the highest biomass on average according to the experiment, which at the RVD formed phytocenosis with stem number per plant 2.60 pcs, leaf number per plant 7.74 pcs, plant height 16.51 cm, and plant weight 0.80 g. The level of variability in plant height was moderate (Cv = 14.08%) and for leave number, stem number, and plant weight it was significant (Cv = 18.39%; Cv = 21.54% and Cv = 29.89%, respectively).

Adaptation potential of Miscanthus in a solonetz agricultural landscape

The aim of the study was to assess the ecological adaptability of Miscanthus cv. Soranovsky to saline agricultural landscapes and the phytomeliorative effect of the plant on saline soils. Location and time of the study. The field experimental part of the research was carried out in 2018-2020 in the central forest-steppe in the Barabinsky agrolandscape region (Experimental Research Station of the Siberian Federal Center for Agrobiotechnologies). Methods. The common methods of field and vegetation experiments, chemical analysis of soils and plant samples were used in the study. Results. Miscanthus can grow on solonetzic soils, providing a biomass yield of up to 5 t/ha under dry growing season conditions. The removal of nutrients from the soil by the biomass of Miscanthus stems was found to be low (8.2 kg/ha of nitrogen, 1.4 kg/ha of phosphorus and 9.7 kg/ha of potassium per year) due to their annual reutilization into rhizomes. This fact allow to avoid the danger of soil depletion during long-term cultivation of crops. Growing Miscanthus on meadow-chernozem solonetz for an average of three years led to changes in soil properties such as a decrease in pH, and changes in salts chemistry in the soil solution, manifested as a decrease in sodium bicarbonate content. Conclusions. Miscanthus as a crop has wide adaptation capabilities in relation to the marginal lands of the solonetz zone of West Siberia. Miscanthus plantings have a beneficial environment-forming effect on solonetz soils, due to the enrichment of soils with mineral nutrition elements and improvement of soil chemical properties.

Observation-based sowing dates and cultivars significantly affect yield and irrigation for some crops in the Community Land Model (CLM5)

Abstract. Farmers around the world time the planting of their crops to optimize growing season conditions and choose varieties that grow slowly enough to take advantage of the entire growing season while minimizing the risk of late-season kill. As climate changes, these strategies will be an important component of agricultural adaptation. Thus, it is critical that the global models used to project crop productivity under future conditions are able to realistically simulate growing season timing. This is especially important for climate- and hydrosphere-coupled crop models, where the intra-annual timing of crop growth and management affects regional weather and water availability. We have improved the crop module of the Community Land Model (CLM) to allow the use of externally specified crop planting dates and maturity requirements. In this way, CLM can use alternative algorithms for future crop calendars that are potentially more accurate and/or flexible than the built-in methods. Using observation-derived planting and maturity inputs reduces bias in the mean simulated global yield of sugarcane and cotton but increases bias for corn, spring wheat, and especially rice. These inputs also reduce simulated global irrigation demand by 15 %, much of which is associated with particular regions of corn and rice cultivation. Finally, we discuss how our results suggest areas for improvement in CLM and, potentially, similar crop models.

Вплив умов року, строку сівби та попередника на формування сили борошна генотипів Triticum aestivum L.

Вплив умов року, строку сівби та попередника на формування сили борошна генотипів Triticum aestivum L.

Interseeded cover crops did not cause corn yield loss in eastern North Dakota

AbstractNorth Dakota is a transitional semiarid region with annual precipitation in the eastern part of the state of about 50–55 cm, mostly from rainfall. The moisture demand from interseeding cover crops into standing corn (Zea mays) early in the season has been a concern and is likely why most corn growers do not interseed cover crops. Corn grain yield was determined in response to interseeding of cereal rye (Secale cereale) or oat (Avena sativa), radish (Raphanus sativus), and camelina (Camelina sativa) and incremental fertilizer nitrogen (N) application rates for five site‐years in the eastern North Dakota. Fifty‐eight days and 35 days of leaf wetness from dew in 2019 and 2020, respectively, were recorded. Cumulative dew accumulation since cover crop emergence was 5.6 mm and 3.5 mm in 2019 and 2020, respectively. Interseeding and its interactions with fertilizer‐N rate did not influence the grain yield. However, cereal rye produced the most biomass of the cover crop species, but the amount varied with site and growing season conditions. Late October, cereal rye biomass produced was 98.8 kg ha−1 in 2018, 352 kg ha−1 in 2019, and 70.3 kg ha−1 in 2020 at the Gardner site. Interseeding did not reduce grain yield loss compared to control. Outcomes will encourage corn growers to adopt cover crops without any changes in their fertilizer N application.

Impact of climate change under the RCP8.5 emission scenario on multivariable agroclimatic indices in Western Canada from convection-permitting climate simulation

Climate change will impact crop production in Western Canada by modifying growing season conditions. Precipitation pattern changes and warmer temperatures will pose significant risks to crops. Studies have shown that multivariable agroclimatic indices can enhance climatic impact assessment on crop production. This study uses multivariable agroclimatic indices to assess how climate change may impact crop production in western Canada by the end of the 21st century. We use convection-permitting regional climate simulations for the current (CTL) and future climate under the Representative Concentration Pathway 8.5 scenario (RCP8.5) scenario based on the pseudo-global warming (PGW) approach to assess the impact of the climate on growing season indices. CTL and PGW are bias-corrected to the Global Environmental Multiscale (GEM) Canadian Precipitation Analysis (CaPA) (GEM-CaPA) dataset using the multivariate quantile mapping method. Our study analyses Effective Precipitation (Pe), Temperature Humidity Index (THI), and Precipitation Intensity Index (PII) at seasonal and sub-seasonal scales as they apply to cool-season crops. The CTL simulation shows a good performance in reproducing the spatial patterns and the temporal variability of the selected indices in western Canada. Results show that precipitation (Effective Precipitation) will decrease by over 60 mm (40 mm), rainy days will decrease by up to 10 days, and precipitation intensities will increase across western Canada. Warming will lead to THI unit increases of about 3.5 (>5) in the prairies (northeastern parts of western Canada in June). This study’s findings can be useful in generating appropriate information to inform policy on adaptation for sustainable crop production by the end of the 21st century.

Water use efficiency and climate legacies dominate beech growth at its rear edge

Abstract Rear‐edge tree populations are experiencing a combination of higher temperatures and more intense droughts that might push individuals beyond their tolerance limits. This trend towards rising atmospheric [CO2] is concurrent with an increase in intrinsic water use efficiency (iWUE), which theoretically enhances photosynthesis and decrease evapotranspiration rates, consequently improving tree resistance to drought. However, it remains unclear whether iWUE is favouring tree growth under current climate conditions, particularly when climate and iWUE legacy effects are simultaneously considered. We evaluated this question with an extensive sampling along Iberian rear‐edge (dry) populations comprising four mountain ranges and two distinct altitudes. We simultaneously examined the effects of climate and iWUE on secondary growth using annually resolved basal area increments (BAIs) for the period 1901–2017. We used linear mixed models including second‐order autocorrelation and 1‐year legacy effects of iWUE and summer drought. BAI and iWUE increased across the studied period. iWUE increase was driven by changes in atmospheric CO2 concentration and water availability during the growing season. Climate and iWUE exerted direct and lagged effects on beech growth. Water availability during growing season was the main driver of tree growth, combining direct and indirect effects through its impact on iWUE. Legacy effects of water availability and iWUE were more important than growing season conditions. The net effect of iWUE shifted when lagged effects were considered, resulting in a net negative impact on tree growth. Synthesis: Our results reveal that climate and iWUE legacy effects must be considered to assess the net iWUE effect on secondary growth. Considering lagged effects, the current increase in iWUE is constraining tree growth. Modelling efforts of tree growth response to climate warming should include climate and iWUE legacy effects to adequately assess terrestrial ecosystem carbon balance.

Determination of the effect of abiotic stress on the oxidative potential of edible potato tubers

Stress factors occurring during the growing season and potato storage, can negatively affect the quality of tubers, including an increased tendency to enzymatic darkening. Abiotic stress due to water shortage is a major factor limiting agricultural production. The purpose of the study was to determine the effect of cultivation technology based on the use of biostimulant, hydrogel and irrigation as well as storage on the propensity to darkening and the content of sugars and organic acids. The results show that genotypic and technological variability in interaction with growing season conditions had a significant (p < 0.05) effect on the oxidative potential (OP) of potato tubers. The Denar cultivar, compared to the ‘Gardena’, was characterized by a lower tendency to enzymatic darkening. Application of biostimulant and hydrogel generally contributed to lowering the oxidative potential of the tested cultivars. The application of anti-stress agents had no effect on organic acid content. The long-term storage caused an increase in the content of total sugars (TS) (22%), reducing sugars (RS) (49%), chlorogenic acid (ACH) (11%), and loss of ascorbic acid (AA) (6%) in the tubers which contributed to an increase in the oxidative potential of potato tubers (16%). The correlation coefficients obtained (p < 0.05) confirm the dependence of OP on the concentration of organic acids.

Investigating the relationship between growing season quality and childbearing goals

Agricultural production and household food security are hypothesized to play a critical role connecting climate change to downstream effects on women’s health, especially in communities dependent on rainfed agriculture. Seasonal variability in agriculture strains food and income resources and makes it a challenging time for households to manage a pregnancy or afford a new child. Yet, there are few direct assessments of the role locally varying agricultural quality plays on women’s health, especially reproductive health. In this paper we build on and integrate ideas from past studies focused on climate change and growing season quality in low-income countries with those on reproductive health to examine how variation in local seasonal agricultural quality relates to childbearing goals and family planning use in three countries in sub-Saharan Africa: Burkina Faso, Kenya, and Uganda. We use rich, spatially referenced data from the Performance Monitoring for Action (PMA) individual surveys with detailed information on childbearing preferences and family planning decisions. Building on recent advances in remote monitoring of seasonal agriculture, we construct multiple vegetation measures capturing different dimensions of growing season conditions across varying time frames. Results for the Kenya sample indicate that if the recent growing season is better a woman is more likely to want a child in the future. In Uganda, when the growing season conditions are better, women prefer to shorten the time until their next birth and are also more likely to discontinue using family planning. Additional analyses reveal the importance of education and birth spacing in moderating these findings. Overall, our findings suggest that, in some settings, women strategically respond to growing season conditions by adjusting fertility aspirations or family planning use. This study also highlights the importance of operationalizing agriculture in nuanced ways that align with women’s lives to better understand how women are impacted by and respond to seasonal climate conditions.

Investigating Seasonal Agriculture, Contraceptive Use, and Pregnancy in Burkina Faso

Seasonal shifts in community-level agricultural production and their impact on the severity of the annual hunger season and household coping behaviors are important themes in climate change–health research. The relationship between seasonal variability, childbearing, and reproductive health, however, is less well understood. In this research, we combine detailed, spatially referenced Performance Monitoring for Action (PMA) data collected for Burkina Faso in 2017 and 2018 and a community-specific measure of seasonal agricultural quality to assess the relationship between seasonal agricultural variation and individual-level fertility and two dimensions of reproductive health: contraceptive use and pregnancy. We also incorporate data related to the family planning service environment. Results from cross-sectional regression models indicate that a better than average agricultural season might increase contraceptive use among all women, and analyses of monthly behaviors during and just after the growing season suggest that better than average growing season conditions might actually reduce contraceptive use among women who have no children or who are in their prime childbearing years. The results therefore indicate that women who are building their families might be less likely to use contraception and are perhaps more interested in timing births to occur following better than average growing seasons.

Effect of Polymer-Coated Urea/Urea Blends on Corn Yields under Short Growing Season Conditions in Eastern Canada

Polymer-coated urea (PCU) was developed to better synchronize nitrogen (N) supply with crop needs and reduce N losses. The objective of this work was to evaluate the effects of different N rates prepared using combinations of urea and ESN (PCU) on corn (Zea mays L.), grain yield, yield components, in-season nutritional status, and residual soil N. Field experiments were conducted on two sites in eastern Ontario (Canada); Kemptville (sandy loam) and Winchester (clay-loam), and repeated over three years (2011–2013). A total of ten treatments were applied using combinations of three N rates (50, 100, and 150 kg N ha−1) and three fertilizer proportions (100% urea, 75:25 urea:ESN, and 60:40 urea:ESN) for each rate. The tenth treatment consisted of a non-fertilized control (0 N). Grain yield was significantly affected by N source, N rate, site, and year. There was no significant effect of the N source in most sites/years. In the wetter season 2013, treatment 100N60:40 in the sandy site produced a similar yield to treatments receiving 150 kg N ha−1. In the clay-loam site, the 150N75:25 treatment had a yield advantage of 11–12% compared with straight urea. Chlorophyll index generally increased with the higher N application rate. The other grain parameters were little affected by the N rate or source. Soil residual mineral N tended to increase with ESN blends at 100 and 150 kg N ha−1 compared with straight urea. Our findings indicate that replacing a portion of urea with PCU might save N in lighter soils prone to leaching especially in wet years without affecting yields.

The growing factors impact the productivity of new soft winter wheat varieties

Purpose. To determine the growing factors impact the economically valuable characteristics of new soft winter wheat varieties. Methods. Field, biochemical methods, ANOVA. Results. The influence of the growing zone, the growing season conditions and the genotype of the soft winter wheat varieties on yield, protein and gluten content were determined. The conditions of the growing zone have the greatest influence on studied varieties yield – 73%. On average, for 2020–2021, the maximum yield was obtained in the Forest-Steppe zone – 6.23–8.39 t/ha. In the Forest zone, the yield of studied soft winter wheat varieties was 5.31–7.02 t/ha. For the Steppe zone, the yield was within 5.16–6.63 t/ha. It was determined that varieties which showed low yield in the Forrest zone were characterized by higher yield in the Steppe zone. It was found that the growing zone (49%) and growing season (42%) conditions have the greatest effect on the protein content in grain of studied varieties. It was determined that variety ‘MANDARIN’ was characterized by the highest protein content in all growing zones (14.5–16.4%). In the Steppe and Forest-Steppe zones, high protein content was identified in grain of wheat varieties ‘Tata Mata’ (13.6–14.3%), ‘Eneida’ (13.6–14.3%) and ‘Novator’ (14.2 and 13.2%), in the Forest zone – in grain of varieties ‘Vahoma’ and ‘Eneida’ – 13.4% each. It was found that the growing zone conditions impacted gluten content in grain of studied wheat varieties by 64%, the influence of the growing season conditions was 28%. The effect of variety genotype on protein and gluten content was 5 and 4%, respectively. The grain of soft winter wheat varieties ‘MANDARIN’ and ‘Eneida’ contained the largest amount of gluten in all growing zones (27.7–31.8% and 27.3–30.3%). For the Steppe and Forest-Steppe zones, a high gluten content was found in grains of varieties ‘Illusion’ (28.4 and 30.8%) and ‘Tata Mata’ (27.8 and 29.8%). Conclusions. It was found that growing zone conditions of soft winter wheat varieties (73%) and the interaction of factors zone × year (21%) impacted the yield significantly. The growing zone conditions (49 and 64%), growing season conditions (21 and 28%) and genotype of variety (5 and 4%, respectively) had a significant influence on protein and gluten content. Therefore, a significant influence of growing zone conditions on the productivity indicators of soft winter wheat determines the need to select varieties in order to obtain a high yield, taking into account the soil and climatic zone

The Content of Ash Elements in the Above-Ground Organs of Some &lt;i&gt;Crataegus&lt;/i&gt; (Rosaceae) Species

Abstract—The study assessed the content of ash elements in the dry matter of fruits, flowers and leaves of 19 hawthorn (Crataegus L.) species. The plants from the collection of the Botanical Garden-Institute of the Volga State University of Technology (VSUT), the Mari El Republic, were studied. The content of eight elements was determined by atomic absorption spectrometry. It is shown that ash and trace elements content is species-specific. The ash content in dry fruits is highest in C. flabellate (Bosc) K. Koch and C. macracantha Lodd., and lowest in C. × almaatensis Pojark. and C. altaica (Loud.) Lange. The highest content of Fe was found in C. pinnatifida Bunge, Mn – in C. flabellate (Bosc) K. Koch, Zn – in C. volgensis Pojark., C. maximowiczii C.K. Schneid. and C. nigra Waldst. et Kit., Cu – in C. volgensis Pojark., Ni, Sr and Co – in C. macracantha Lodd., Cd – in C. altaica (Loud.) Lange, C. macracantha Lodd., C. volgensis Pojark. Difference in the fruit elemental composition between hawthorn species may be due to the difference in proportion of pulp and seeds. The content of ash and mineral elements in hawthorn fruits varies depending on the growing season conditions. The content of Fe, Zn and Ni increases in years with warm and humid summers, while the content of Mn decreases, but the weather conditions of the growing season account for only 3.8 to 28.8% of the variance of values. In hawthorn, the concentration of trace elements essential for humans, especially Zn, is significantly higher in flowers, than in fruits, and, on the contrary, concentration of potentially toxic Sr is higher in fruits. In leaves, especially harvested in autumn, Sr content is tens of times higher than in fruits.

Influence of climate fluctuations on Pinus palustris growth and drought resilience

The longleaf pine (Pinus palustris Mill.) ecosystem is an endangered ecosystem in the southeastern USA, and efforts to restore the species are ongoing. However, in recent decades, the region has experienced drastic fluctuations between wet and dry growing season conditions from year to year, and it is not fully understood how these fluctuations have influenced the growth of P. palustris. To address this topic, we cored P. palustris trees in woodlands of southwest Georgia and used dendrochronology techniques to determine how climate fluctuations have influenced the growth and drought resilience of P. palustris. We also cored slash pine (Pinus elliottii Engelm.) trees in the same woodlands to compare growth between species. While P. palustris growth was less impacted by adverse climate conditions compared to P. elliottii, the strength of correlations between P. palustris growth and temperature, precipitation, and Palmer Drought Severity Index (PDSI) changed over time. In recent decades, climate conditions during the growing season became more influential on P. palustris growth than the previous year's conditions. This is concerning given that drought severity during the growing season has been increasing. Our results also indicate that P. palustris was less resilient to droughts during the 2000s and 2010s than to those of the 1950s. Under this new climate paradigm, our results suggest that P. palustris might be more susceptible to growth reductions and less resistant to droughts than once expected. This work highlights the importance of understanding the impact of novel climate conditions on P. palustris and has implications for restoration efforts, such as using silvicultural treatments that reduce tree vulnerability to drought (e.g., thinning) and promote other climate-adapted species in mixture with P. palustris.

Beautiful Days in the Neighborhood: Land–Atmosphere Interactions as Drivers of Forest Expansion

Abstract We explore the possible role of plant–atmosphere feedbacks in accelerating forest expansion using a simple example of forest establishment. We use an unconventional experimental design to simulate an initial forest establishment and the subsequent response of climate and nearby vegetation. We find that the forest’s existence produces favorable nearby growing-season conditions that would promote forest expansion. Specifically, we consider a hypothetical region of forest expansion in modern Alaska. We find that the forest acts as a source of heat and moisture for plants to the west, leading them to experience earlier springtime temperatures, snowmelt, and growth. Summertime cooling and cloud formation over the forest also drive a circulation change that reduces summertime cloud cover south of the forest, increasing solar radiation reaching plants there and driving warming. By isolating these vegetation–atmosphere interactions as the mechanisms of increased growth, we demonstrate the potential for forest expansion to be accelerated in a way that has not been highlighted before. These simulations illuminate two separate mechanisms that lead to increased plant growth nearby: 1) springtime heat advection and 2) summertime cloud feedbacks and circulation changes; both have implications for our understanding of past changes in forest cover and the predictability of biophysical impacts from afforestation projects and climate change–driven forest-cover changes. By examining these feedbacks, we seek to gain a more comprehensive understanding of past and potential future land–atmosphere interactions. Significance Statement This study investigates whether the emergence of a high-latitude forest could influence the way water and energy are exchanged between the land and atmosphere in a way that impacts nearby growing conditions and subsequent forest expansion. We use a computer model to simulate a climate with and without forest establishment in the high latitudes and test the response of plants surrounding the forest to the two different climates. We find that a forest is indeed able to spur neighboring plant growth by modifying regional climate and producing more favorable growing conditions for surrounding vegetation. Specifically, forest establishment can bring better growing conditions to plants adjacent to it by warming the air and altering nearby circulation and cloud cover.