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Summary: Changes to flowering phenology are a key response of plants to climate change. However, we know little about how these changes alter temporal patterns of reproductive overlap (i.e. phenological reassembly).We combined long‐term field (1937–2012) and herbarium records (1850–2017) of 68 species in a flowering plant community in central North America and used a novel application of Bayesian quantile regression to estimate changes to flowering season length, altered richness and composition of co‐flowering assemblages, and whether phenological shifts exhibit seasonal trends.Across the past century, phenological shifts increased species' flowering durations by 11.5 d on average, which resulted in 94% of species experiencing greater flowering overlap at the community level. Increases to co‐flowering were particularly pronounced in autumn, driven by a greater tendency of late season species to shift the ending of flowering later and to increase flowering duration.Our results demonstrate that species‐level phenological shifts can result in considerable phenological reassembly and highlight changes to flowering duration as a prominent, yet underappreciated, effect of climate change. The emergence of an autumn co‐flowering mode emphasizes that these effects may be season‐dependent. [ABSTRACT FROM AUTHOR]

Textural deterioration in frozen vegetables is a result of softening after freeze-thawing and is a critical issue to address. In the present study, field experiments were conducted on broccoli using six cultivars of three sizes (i.e., different maturities) in two seasons (spring and winter) to evaluate the relationship between the level of tissue softening caused by the freezing process and composition of pectin, which is a main component of the cell wall. The mechanical properties after freeze-thawing depended more on the growing season than on the cultivar or maturity, i.e., the maximum stress after freeze-thawing of spring broccoli was higher than that of winter broccoli. Between the winter broccoli, the samples harvested at lower temperatures showed more pronounced softening after thawing. For all broccolis, the temperature during harvest was strongly correlated with the maximum compressive stress of frozen broccoli (R = 0.867). Broccoli harvested in winter had a higher ratio of galacturonic acid in water-soluble pectin than that harvested in spring, indicating weakened cell wall adhesion. However, the absence of a substantial correlation between the pectin content and mechanical properties of broccoli, suggests that other factors such as cold-responsive materials are also involved in the tissue softening of frozen broccoli. [ABSTRACT FROM AUTHOR]

Cotton is a commercial crop of global importance whose versatile fibre is widely used in the textile industry. Cotton is vulnerable to infectious pathogens, including viruses, that are a major threat to cotton production. Cotton blue disease is caused by cotton leafroll dwarf virus (CLRDV), a polerovirus transmitted by aphids. This virus is controlled by sowing cotton varieties resistant to CLRDV, although, in recent years an atypical variant (CLRDV‐at), that breaks the resistance, has been identified. An outbreak of a disease occurred in cotton fields of the province of Chaco, in the north‐west of Argentina, in the 2014–2015 growing season. NuOpal cotton plants (a variety resistant to CLRDV and susceptible to CLRDV‐at) showed mosaic symptoms and had virus‐transmitting insect vectors, such as aphids and whiteflies (Bemisia tabaci). The symptoms were common for virus infections but different from those caused by CLRDV or CLRDV‐at. According to a reverse transcription‐PCR analysis with polerovirus primers and sequencing, the plants contained CLRDV‐at. To identify the complete virome of these plants, we performed a massive RNA‐based deep sequencing assay using Illumina technology. As a result, a new begomovirus that infects cotton in Argentina was identified. Structural and functional annotation indicated that its sequences corresponded to complete DNA components A and B of a novel New World bipartite begomovirus. Genetic distance and evolutionary analyses support that the detected sequences correspond to a new virus, which we propose to name cotton mosaic virus (CoMV). In addition, we report the first begomovirus and polerovirus coinfection in cotton. [ABSTRACT FROM AUTHOR]

The conservation and elimination of the growing point of Leymus chinensis (Trin.) Tzvel. are two common contrasted scenarios during grazing. However, the biomass and nutrient allocation in L. chinensis, as well as their contribution to yield under these conditions are unclear. Therefore, a simulated grazing experiment was conducted using a factorial design that combined two defoliation heights (conservation versus elimination of growing points) and four plant heights (18, 24, 31, and 35 cm) during two growing seasons (2020 and 2021), resulting in eight treatments. Additionally, the experiment also included two identical control treatments with a single mowing in mid‐August. The results demonstrated that conservation treatments for the growing point increased the regeneration time of L. chinensis during the entire growing season in both years compared to elimination treatments for the growing point, due to the alteration in biomass allocation priority and C: N: P stoichiometric ratio between stems and leaves of L. chinensis, as well as root morphological traits. The growth strategy in the treatment with 17 cm defoliation height at 35 cm plant height demonstrated the optimal combination, resulting in stabling the accumulated DM yield of L. chinensis in both years. The findings emphasize the significance of comprehending the correlation between the growing point of L. chinensis and its yield, providing a pioneering approach to guide sustainable grazing practices for L. chinensis grassland. [ABSTRACT FROM AUTHOR]

Near real-time (NRT) crop type mapping plays a crucial role in modeling crop development, managing food supply chains, and supporting sustainable agriculture. The low-latency updates on crop type distribution also help assess the impacts of weather extremes and climate change on agricultural production in a timely fashion, aiding in identification of early risks in food insecurity as well as rapid assessments of the damage. Yet NRT crop type mapping is challenging due to the obstacle in acquiring timely crop type reference labels during the current season for crop mapping model building. Meanwhile, the crop mapping models constructed with historical crop type labels and corresponding satellite imagery may not be applicable to the current season in NRT due to spatiotemporal variability of crop phenology. The difficulty in characterizing crop phenology in NRT remains a significant hurdle in NRT crop type mapping. To tackle these issues, a novel emergence-based thermal phenological framework (EMET) is proposed in this study for field-level NRT crop type mapping. The EMET framework comprises three key components: hybrid deep learning spatiotemporal image fusion, NRT thermal-based crop phenology normalization, and NRT crop type characterization. The hybrid fusion model integrates super-resolution convolutional neural network (SRCNN) and long short-term memory (LSTM) to generate daily satellite observations with a high spatial resolution in NRT. The NRT thermal-based crop phenology normalization innovatively synthesizes within-season crop emergence (WISE) model and thermal time accumulation throughout the growing season, to timely normalize crop phenological progress derived from temporally dense fusion imagery. The NRT normalized fusion time series are then fed into an advanced deep learning classifier, the self-attention based LSTM (SAtLSTM) model, to identify crop types. Results in Illinois and Minnesota of the U.S. Corn Belt suggest that the EMET framework significantly enhances the model scalability with crop phenology normalized in NRT for timely crop mapping. A consistently higher overall accuracy is yielded by the EMET framework throughout the growing season compared to the calendar-based and WISE-based benchmark scenarios. When transferred to different study sites and testing years, EMET maintains an advantage of over 5% in overall accuracy during early- to mid-season. Moreover, EMET reaches an overall accuracy of 85% a month earlier than the benchmarks, and it can accurately characterize crop types with an overall accuracy of 90% as early as in late July. F1 scores for both corn and soybeans also achieve 90% around late July. The EMET framework paves the way for large-scale satellite-based NRT crop type mapping at the field level, which can largely help reduce food market volatility to enhance food security, as well as benefit a variety of agricultural applications to optimize crop management towards more sustainable agricultural production. [ABSTRACT FROM AUTHOR]

AimMaterials and MethodsResultsConclusionsThe aim of this study was to determine the agronomic, physiological and recovery efficiency of phosphorus in the transition from conventional agriculture to organic agriculture of organomineral fertilizers, which are formed by combining different levels of phosphorus fertilizers and dairy manures at different rates.The study was carried out between 2019 and 2021 during the two wheat growing season in Söke county of Aydın province in the Southwest of Türkiye. In the study, excluding the control (P0), 4 different levels of phosphorus (P1:10, P2:20, P3:30, and P4:40 kg P ha−1) and 4 different doses of dairy manure (DM1:10, DM2:20, DM3:30, and DM4:40 t ha−1) and 16 different organomineral fertilizer combinations were composed. The fertilizer combinations composed were divided into four sub-organomineral fertilization systems (OMF1, OMF2, OMF3, and OMF4). The study was carried out in three replications according to the randomized block design.In the study, according to the averages of both years, the highest agronomic, physiological and recovery efficiency (AE, PE, and RE) was determined as 29.5 kg kg−1, 175.0 kg kg−1 and 16.9% in DM1P1 application (OMF1 system), respectively. The lowest agronomic, physiological and recovery efficiency were recorded as 21.2 kg kg−1, 163.4 kg kg−1 and 13.0% in DM4P4 application (OMF4 system), respectively. As a result, organomineral fertilizers reduced the agronomic, physiological and recovery efficiency of phosphorus by 28.1%, 8.2% and 23.1%, respectively.Finally, it was concluded that the fertilizer use efficiency increased as the amount of phosphorus applied to compose with organomineral fertilizers decreased. [ABSTRACT FROM AUTHOR]

The plant-available soil phosphorus rate and methods for applying phosphatic fertilizer and soil P-fixation capacity are critical factors for lower cotton productivity in Southern Punjab, Pakistan. Hence, a two-year study was conducted in Central Cotton Research Institute (CCRI), Multan, Pakistan, to examine the effects of various P rates and application methods on cotton crop output during the growing seasons of 2014 and 2015. Phosphorus was applied in four rates (0, 40, 80, and 120 kg ha−1 P2O5) using broadcast, band application, and fertigation methods. Results indicated that the impact of P rates was statistically significant on plant height, the number of nodes, monopodial and sympodial branches, leaf area index, harvest index, and seed cotton yield. The greater P application (120 kg P2O5 ha−1) had a better effect on cotton productivity than the lower application rates (0, 40, and 80 kg P2O5 ha−1). The band application responded better on nodes plant−1, sympodial branches plant−1, boll weight, leaf area index, lint yield, and harvest during the growing season 2015. Therefore, by adopting the band application coupled with 120 kg P2O5 ha−1 rather than the conventional method of broadcast, productivity of cotton crops could be increased. [ABSTRACT FROM AUTHOR]

Global change has substantially shifted vegetation phenology, with important implications in the carbon and water cycles of terrestrial ecosystems. Various vegetation phenology datasets have been developed using remote sensing data; however, the significant uncertainties in these datasets limit our understanding of ecosystem dynamics in terms of phenology. It is therefore crucial to generate a reliable large-scale vegetation phenology dataset, by fusing various existing vegetation phenology datasets, to provide comprehensive and accurate estimation of vegetation phenology with fine spatiotemporal resolution. In this study, we merged four widely used vegetation phenology datasets to generate a new dataset using the Reliability Ensemble Averaging fusion method. The spatial resolution of the new dataset is 0.05° and its temporal scale spans 1982–2022. The evaluation using the ground-based PhenoCam dataset from 280 sites indicated that the accuracy of the newly merged dataset was improved substantially. The start of growing season and the end of growing season in the newly merged dataset had the largest correlation (0.84 and 0.71, respectively) and accuracy in terms of the root mean square error (12 and 17 d, respectively). Using the new dataset, we found that the start of growing season exhibits a significant (p < 0.01) advanced trend with a rate of approximately 0.24 d yr−1, and that the end of growing season exhibits a significant (p < 0.01) delayed trend with a rate of 0.16 d yr−1 over the period 1982–2022. This dataset offers a unique and novel source of vegetation phenology data for global ecology studies. [ABSTRACT FROM AUTHOR]

Understanding the complex interactions between genotype-environment dynamics is fundamental for optimizing crop improvement. However, traditional phenotyping methods limit assessments to the end of the growing season, restricting continuous crop monitoring. To address this limitation, we developed a methodology for spatiotemporal registration of time-series 3D point cloud data, enabling field phenotyping over time for accurate crop growth tracking. Leveraging multi-scan terrestrial laser scanning (TLS), we captured high-resolution 3D LiDAR data in a cotton breeding field across various stages of the growing season to generate fourdimensional (4D) crop models, seamlessly integrating spatial and temporal dimensions. Our registration procedure involved an initial pairwise terrain-based matching for rough alignment, followed by a bird's-eye view adjustment for fine registration. Point clouds collected throughout nine sessions across the growing season were successfully registered both spatially and temporally, with average registration errors of approximately 3 cm. We used the generated 4D models to monitor canopy height (CH) and volume (CV) for eleven cotton genotypes over two months. The consistent height reference established via our spatiotemporal registration process enabled precise estimations of CH (R² = 0.95, RMSE = 7.6 cm). Additionally, we analyzed the relationship between CV and the interception of photosynthetically active radiation (IPARf), finding that it followed a curve with exponential saturation, consistent with theoretical models, with a standard error of regression (SER) of 11%. In addition, we compared mathematical models from the Richards family of sigmoid curves for crop growth modeling, finding that the logistic model effectively captured CH and CV evolution, aiding in identifying significant genotype differences. Our novel TLS-based digital phenotyping methodology enhances precision and efficiency in field phenotyping over time, advancing plant phenomics and empowering efficient decision-making for crop improvement efforts. [ABSTRACT FROM AUTHOR]

Maize is the most widely cultivated and major security crop in sub-Saharan Africa. Three foliar diseases threaten maize production on the continent, namely northern leaf blight, gray leaf spot, and southern corn leaf blight. These are caused by the fungi Exserohilum turcicum, Cercospora zeina, and Bipolaris maydis, respectively. Yield losses of more than 10% can occur if these pathogens are diagnosed inaccurately or managed ineffectively. Here, we review recent advances in understanding the population biology and management of the three pathogens, which are present in Africa and thrive under similar environmental conditions during a single growing season. To effectively manage these pathogens, there is an increasing adoption of breeding for resistance at the small-scale level combined with cultural practices. Fungicide usage in African cropping systems is limited due to high costs and avoidance of chemical control. Currently, there is limited knowledge available on the population biology and genetics of these pathogens in Africa. The evolutionary potential of these pathogens to overcome host resistance has not been fully established. There is a need to conduct large-scale sampling of isolates to study their diversity and trace their migration patterns across the continent. [ABSTRACT FROM AUTHOR]

This paper explores whether it is feasible to use the RGB color information in images of wheat canopies that were exposed to low temperatures during the growth season to achieve fast, non-destructive, and accurate determination of the severity of any freeze injury it may have incurred. For the study presented in this paper, we compared the accuracy of a number of algorithmic classification models using either meteorological data reported by weather services or the color gradation skewness-distribution from high-definition digital canopy images acquired in situ as inputs against a reference obtained by manually assessing the severity of the freeze injury inflicted upon wheat populations at three experimental stations in Shandong, China. The algorithms we used to construct the models included in our study were based on either K-means clustering, systematic clustering, or naïve Bayesian classification. When analyzing the reliability of our models, we found that, at more than 85%, the accuracy of the Bayesian model, which used the color information as inputs and involved the use of prior data in the form of the reference data we had obtained through manual classification, was significantly higher than that of the models based on systematic or the K-means clustering, which did not involve the use of prior data. It was interesting to note that the determination accuracy of algorithms using meteorological factors as inputs was significantly lower than that of those using color information. We also noted that the determination accuracy of the Bayesian model had some potential for optimization, which prompted us to subject the inputs of the model to a factor analysis in order to identify the key independent leaf color distribution parameters characterizing wheat freeze injury severity. This optimization allowed us to improve the determination accuracy of the model to over 90%, even in environments comprising several different ecological zones, as was the case at one of our experimental sites. In conclusion, our naïve Bayesian classification algorithm, which uses six key color gradation skewness-distribution parameters as inputs and involves the use of prior data in the form of manual assessments, qualifies as a contender for the development of commercial-grade wheat freeze injury severity monitoring systems supporting post-freeze management measures aimed at ensuring food security. [ABSTRACT FROM AUTHOR]

Tree lines in high latitudes and high altitudes are considered sentinels of global change. This manifests in accelerated encroachment of trees and shrubs and enhanced plant productivity, with currently unknown implications for the carbon balance of these biomes. Given the large soil organic carbon stocks in many tree line soils, we here wondered whether introducing highly productive plants would accelerate carbon cycling through rhizosphere priming effects and if certain soils would be more vulnerable to carbon loss from positive priming than others. To test this, organic and mineral soils were sampled above and below tree lines in the Swedish sub‐arctic and the Peruvian Andes. A greenhouse experiment was then performed to quantify plant‐induced changes in soil mineralisation rates (rhizosphere priming effect) and new C formation using natural abundance labelling and the C4‐species Cynodon dactylon. Several environmental, plant, soil and microbial parameter were monitored during the experiment to complement the observations on soil C cycling. Priming was predominantly positive at the beginning of the experiment, then systematically decreased in all soils during the plant growth season to be mostly negative at the end of the experiment at plant senescence. Independent of direction of priming, the magnitude of priming was always greater in organic than in corresponding mineral soils, which was best explained by the higher C contents of these soils. Integrated over the entire study period, the overall impact of priming (positive and negative) on the soil C balance was mostly negligible. Though net soil C loss was observed in organic soils from the sub‐arctic tundra in Sweden. Most notably, positive and negative priming effects were not mutually exclusive, rather omnipresent across ecosystems, depending on sampling time. The direction of priming seems to be fluctuating with plant productivity, rhizosphere carbon inputs and nutrient uptake. This highlights the need for integrative long‐term studies if we aim to understand priming effects at ecosystem scale and greenhouse and laboratory studies must be validated in situ to enable reliable ecological upscaling. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Background: This study examines seasonal and regional trends in chlorophyll-a concentrations and the dynamics of nitrogen (N) and phosphorus (P) in 32 fishponds (resulting in 150 pond-year cases) employed for fish production. Fishponds have a poor ecological state, requiring further insights for pond management. To gain those insights, monthly data on the pond environment were collected over the growing seasons from April to September (up to 14 years) across lowland to highland regions in Czechia. We used a ratio of dissolved inorganic nitrogen to total phosphorus (DIN:TP) to investigate seasonal patterns of N and P limitations. Results: Fishponds in the lowland region (below 199 m above sea level, a.s.l.) were predominantly N-limited (80%), while ponds in the midland region (200–449 m a.s.l.) exhibited P limitation at the beginning of the growing season (April–May) and N limitation by the end of the season (August–September; 90% of fishponds). Highland fishponds (above 450 m a.s.l.) showed frequent P limitations, especially during the beginning of the season. Chlorophyll-a concentrations varied on both regional and seasonal scales, with the overall phytoplankton biomass peak at 31 ha of pond surface area. Chlorophyll-a remained stable at the beginning of the season regardless of the DIN:TP ratio but increased with a lower DIN:TP ratio by its end. The chlorophyll-a concentrations were lowest at the beginning and highest at the end of the season and decreased with altitude. Conclusions: Seasonal and regional variations in nutrient limitations and chlorophyll-a occur in fishponds. Our study suggests that targeted seasonal nutrient input and enhanced monitoring can significantly improve fishpond management practices and ecosystem stability. [ABSTRACT FROM AUTHOR]

The timing and size of metamorphosis are crucial for the future fitness of organisms with complex life cycles, such as amphibians. In some amphibian species, a portion of tadpoles will metamorphose in their natal year whereas others from the same cohort overwinter as tadpoles. Low temperature and food availability were previously assumed to be the underlying reasons; however, the factors influencing the decision to overwinter as tadpoles or metamorphose in the natal year have not been extensively studied. This study investigated these factors by conducting laboratory‐rearing experiments on Babina subaspera tadpoles. The tadpoles were individually reared under controlled temperature and light conditions that simulated five different growing seasons (i.e., the start month) observed in the field. Four different food quantity levels were set to induce different growth rates, which were measured individually. The results revealed that 33 tadpoles metamorphosed within their natal year, whereas 52 tadpoles were overwintered as tadpoles and metamorphosed the following spring. The size at metamorphosis was larger in tadpoles that metamorphosed after winter than in those that metamorphosed before winter. Whether tadpoles metamorphosed before or after winter was influenced by the individual growth rate and growing season. Tadpoles with slower growth rates were more likely to metamorphose after winter, possibly because slower growth prevented them from reaching the critical size threshold required for metamorphosis before winter. The threshold for the occurrence of larval overwintering varied with the growing season; tadpoles that spawned later in the year were more likely to overwinter, even with a high growth rate. The results suggested that slow‐growing B. subaspera tadpoles with insufficient time until the onset of winter would gain a higher fitness by metamorphosing after winter. This would be advantageous due to the tadpoles' potentially high survival rate during dormancy as well as their larger size at metamorphosis in the following year. [ABSTRACT FROM AUTHOR]

Farmers in the high desert are challenged by a short growing season and slow crop establishment of warm-season vegetables. Yet an increasing demand for local produce in nearby urban areas presents an opportunity to diversify farms while adapting to climate uncertainty. Vegetable rootstocks can confer advantages under biotic and abiotic stress conditions, but information on which and how melon rootstocks can improve management does not exist for high desert and short-season regions. Commercial, squash-hybrid rootstocks (i.e., Cucurbita maxima × C. moschata) were grafted with a common scion (Cucumis melo cv. Sarah's choice). Nine rootstocks in 2021 and four selected rootstocks in 2022 were evaluated in four field trials (two per year) in northern Nevada at two distinct locations. Melon grafting did not consistently increase crop performance in the high desert, and it was influenced by location and year. Throughout the initial half of the harvesting period, grafted plants tended to produce more melons, irrespective of location or year, offering a potential appeal for melon growers operating in shorter growing seasons. However, a slight reduction in fruit quality (i.e., -Brix) was observed in some grafted plants compared with the ungrafted control. The benefits of grafting melons onto squash hybrids in high desert conditions remain uncertain and may depend on microenvironment and farming practices that affect crop establishment, such as mulching effects on soil temperature. [ABSTRACT FROM AUTHOR]

Revealing the dynamic changes of water and heat fluxes in straw-covered farmland ecosystems can provide a theoretical basis for the quantitative regulation of efficient water use by crops under agronomic mulching. Two treatments of straw mulching (S) and none mulching (N) were set up in the experiment. The dynamic changes of net radiation flux (Rn), latent heat flux (λET), sensible heat flux (H) and soil heat flux (G) of farmland energy flux elements under straw mulching in North China Plain and their responses to meteorological factors were studied by using Bowen ratio energy balance method and measured data. The results showed that the diurnal variation of Rn, λET and H in each growth period showed an obvious single-peak pattern. Compared with N treatment, S treatment mainly reduced the daily peak of Rn, λET and H in each growth period in both wheat and maize growing seasons. However, from the perspective of daily mean value, S treatment increased the proportion of λET in Rn in wheat growing season, and the proportion of λET in Rn in the total growth period of S treatment (68.8%) was slightly higher than that of N treatment (68.4%). The proportion of λET to Rn in the total growth period of S treatment (65.0%) was lower than that of N treatment (65.9%). The meteorological factor that had the greatest influence on instantaneous λET in wheat growing season and maize growing season was Rn, and the other factors had little influence. Each meteorological factor affects instantaneous λET through direct and indirect effects. The influence of Rn on instantaneous λET is mainly reflected in the direct effect, and the other factors are mainly reflected in the indirect effect. [ABSTRACT FROM AUTHOR]

To non-destructively and rapidly monitor the chlorophyll content of winter wheat leaves under CO2 microleakage stress, and to establish the quantitative relationship between chlorophyll content and sensitive bands in the winter wheat growing season from 2023 to 2024, the leakage rate was set to 1 L/min, 3 L/min, 5 L/min, and 0 L/min through field experiments. The dimensional reduction was realized, fractional differential processing of a wheat canopy spectrum was carried out, a multiple linear regression (MLR) and partial least squares regression (PLSR) estimation model was constructed using a SPA selection band, and the model's accuracy was evaluated. The optimal model for hyperspectral estimation of wheat SPAD under CO2 microleakage stress was screened. The results show that the spectral curves of winter wheat leaves under CO2 microleakage stress showed a "red shift" of the green peak and a "blue shift" of the red edge. Compared with 1 L/min and 3 L/min, wheat leaves were more affected by CO2 at 5 L/min. Evaluation of the accuracy of the MLR and PLSR models shows that the MLR model is better, where the MLR estimation model based on 1.1, 1.8, 0.4, and 1.7 differential SPAD is the best for leakage rates of 1 L/min, 3 L/min, 5 L/min, and 0 L/min, with validation set R2 of 0.832, 0.760, 0.928, and 0.773, which are 11.528, 14.2, 17.048, and 37.3% higher than the raw spectra, respectively. This method can be used to estimate the chlorophyll content of winter wheat leaves under CO2 trace-leakage stress and to dynamically monitor CO2 trace-leakage stress in crops. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau holds the world's largest alpine permafrost and is undergoing an acceleration of warming. Phenological shifts over alpine permafrost in a warmer world have been little studied and are greatly underrepresented in current syntheses.Here, we conducted seasonal and gradient temperature‐controlled experiments in a permafrost‐affected meadow to evaluate how warming drives shifts in spring and autumn phenology, and associated growing‐season length at both community and species levels.We found that there is no sign of slowdown in spring advance with warming under a higher year‐around warming treatment, aligning with a future medium warming scenario. Although spring advance led to an advance in autumn senescence according to spring‐only warming experiments, the advance could not offset the delay due to concurrent warming. As a result, year‐around warming significantly delayed autumn senescence, although there was a deceleration in delay with warming under high temperature treatment than under the low one.This finding can be attributed to the possibility that winter warming is insufficient to reduce chilling accumulation, which would not delay spring phenology and then lead to a non‐slowdown in spring phenological advancement. Taken together, there is no slowdown in an extension of growing season length with warming under a higher year‐around warming treatment, with an increase of length by 9 and 21 days at the end of this century under a CO2 stabilization and medium warming scenarios, respectively.Synthesis. Our results suggest that a continued growing season extension at least under the medium warming scenario would help permafrost‐affected meadow ecosystems to mitigate permafrost carbon release on the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Water and heat flux is a key components for the energy exchange of surface air in atmospheric circulation. The driving mechanism can include the sensible heat flux (H) and latent heat flux (LE). There is a great variation in the water and heat flux in desert grasslands. The influencing factors are of great significance to understanding the regional exchange of water and heat flux against climate change. This study aims to explore the variation patterns of water and heat flux at different time scales. The eddy covariance and continuous observation were also utilized from automatic meteorological stations in Xilamuren Town, Damao Banner, Inner Mongolia, China. After that, the regulatory mechanisms of environmental factors were proposed for the desert grassland during growing seasons (April to October) in 2018 and 2019. A systematic analysis was made on the H, LE, and energy ratio (H/LE) in the desert grasslands at different time scales, together with their environmental control mechanisms. The results indicated that the H of plants was the main form of near-surface energy consumption in the desert grassland during the growth season. There was an unimodal variation in the H and LE on an hourly scale. The H and LE peaks mainly occurred between 12:00 and 14:00, where the time of LE peak occurrence was lagged by 1-2 h, compared with the H. The variation range of H and LE between 8:00—18:00 was 0.1-160.5 and 15.4-90.9 W/m2, respectively. The main influencing factors of H were the relative humidity (RH), wind speed (Ws), and vapor pressure deficit (VPD), with the correlation coefficients (r) of -0.66, 0.72, and 0.61, respectively. The main influencing factors of LE were the RH, Ws, soil temperature (Ts), and VPD, with correlation coefficients of -0.074, 0.032, 0.61, and 0.67, respectively. The main influencing factors of H/LE were the RH, Ws, Ts, and VPD, with correlation coefficients of -0.74, 0.86, -0.23, and 0.24, respectively. There was an outstanding seasonal variation in the H and LE on a daily scale. The maximum is also reached before and after the middle stage of plant growth. The daily variation ranges of H, LE, and H/LE during the plant growth season were 4.2-186.1, 1.3-160.9 W/m2, and 0.18-26.50, respectively. The main influencing factors of H were the RH, Ws, air temperature (Ta), precipitation (P), and VPD, with correlation coefficients of 0.13, 0.21, -0.15, and 0.39, respectively. The main influencing factors of LE were the RH, Ws, and Ta, where there was no significant correlation with the Ts and P. The main influencing factor of H/LE was the RH with a correlation coefficient of -0.16, which was not significantly correlated with other factors. On a monthly scale, the H and LE were approximated a unimodal change. The average H and LE reached the maximum in June and August. The variation ranged of H and LE were 36.4-133.8 and 15.6-96.3 W/m2, respectively, from April to October. The LE was the main mode of energy dissipation in summer. The main influencing factors of H were the Ts, Ta, and VPD, where there was the strongest positive correlation of VPD. The LE was significantly correlated with the RH, Ws, Ts, Ta, and P, where the P shared the strongest positive correlation (r =0.75). There was a significant correlation between H/LE with Ts, Ta, P, and VPD, in which the Ts shared the strongest positive correlation (r =0.76). The finding can provide the theoretical basis and practical significance for vegetation restoration and environment protection in ecological functional grassland. [ABSTRACT FROM AUTHOR]

In this work we analyse yearly standardized precipitation evapotranspiration index for accumulation timescale of 6 months (SPEI‐6) for August which has been identified as a strong proxy for corn production in Serbia. By applying recently proposed method generalized weighted permutation entropy (GWPE), which provides the information about predictability of large/small fluctuations in nonstationary time series, on SPEI index calculated from high‐resolution gridded dataset for the period 1951–2022, we found that the small fluctuation sequences of consecutive 4‐year SPEI values are the most predictable (indicated by lowest entropy values). The order of large fluctuation sequences is less predictable, while the order of sequences considering all magnitudes of fluctuations are the least predictable (indicated by highest entropy values). We also analysed 4‐month SPEI‐6 sequences for May, June, July and August (during the growing season of corn) along the years under study and found that they display lower GWPE values and thus are more predictable than yearly SPEI‐6 August sequences (small fluctuations displaying lower entropy values than large fluctuations). Regarding spatial distributions, in both cases SPEI‐6 sequences show similar pattern for large fluctuations: higher predictability (lower entropy values) in northern and eastern part of Serbia and lower predictability (higher entropy values) in southern and western part. For small fluctuations spatial distribution of GWPE values indicates that yearly SPEI‐6 August series are more predictable in the western part of the country while May to August monthly SPEI‐6 sequences are more predictable in the eastern part. [ABSTRACT FROM AUTHOR]

The Heihe River Basin, located in Northwest China, serves as a major commodity grain base in China due to its state‐of‐the‐art irrigation system. The rapid increase in soil moisture caused by irrigation can alter the land–atmosphere energy fluxes and regulate regional climate. However, the effects and mechanisms of irrigation on wind speed related to thermodynamics remain unclear. Here, we carried out two 10‐year numerical simulations using the Weather Research and Forecast (WRF) model incorporating a real‐time irrigation scheme. By comparing the simulation differences (including and excluding irrigation), we found that irrigation significantly decreased the daily mean and maximum wind speed at 10 m above ground by 0.30 and 0.55 m·s−1, respectively, in the irrigated area during the growth season. Such surface wind slowdown could be explained by irrigation‐induced surface air cooling and, hence, intensifying atmospheric column stability, weakening turbulent momentum transport, as well as opposite‐to‐prevailing winds vector anomaly caused by increased southward pressure gradient. Meanwhile, we also found wind slowdown mainly occurs below 1100 m while acceleration effect above that level. It was highlighted that the surface wind slowdown effect of irrigation substantially improved the performance of the WRF model. Due to the surface wind slowdown effect of irrigation, the positive bias of daily mean and maximum wind speed simulated by the WRF model was reduced by 15.3% and 27.4%, respectively. Our findings implicate the potential importance of irrigation in improving the performance of climate models as well as in explaining the phenomenon of global stilling. [ABSTRACT FROM AUTHOR]

Northwest China has undergone notable alterations in climate and vegetation growth in recent decades. Nevertheless, uncertainties persist concerning the response of different vegetation types to climate change and the underlying mechanisms. This study utilized the Normalized Difference Vegetation Index (NDVI) and three sets of meteorological data to investigate the interannual variations in the association between vegetation and climate (specifically precipitation and temperature) from 1982 to 2015. Several conclusions were drawn. (1) RNDVI-GP (relationship between Growing Season NDVI and precipitation) decreased significantly across all vegetation, while RNDVI-GT (relationship between Growing Season NDVI and temperature) showed an insignificant increase. (2) Trends of RNDVI-GP and RNDVI-GT exhibited great variations across various types of vegetation, with forests displaying notable downward trends in both indices. The grassland exhibited a declining trend in RNDVI-GP but an insignificant increase in RNDVI-GT, while no significant temporal changes in RNDVI-GP or RNDVI-GT were observed in the barren land. (3) The fluctuations in RNDVI-GP and RNDVI-GT closely aligned with variations in drought conditions. Specifically, in regions characterized by VPD (vapor pressure deficit) trends less than 0.02 hpa/yr, which are predominantly grasslands, a rise in SWV (soil water volume) tended to cause a reduction in RNDVI-GP but an increase in RNDVI-GT. However, a more negative trend in SWV was associated with a more negative trend in both RNDVI-GP and RNDVI-GT when the VPD trend exceeded 0.02 hPa/yr, primarily in forests. Our results underscore the variability in the relationship between climate change and vegetation across different vegetation types, as well as the role of drought in modulating these associations. [ABSTRACT FROM AUTHOR]

Acid sulphate soils (ASS) can be classified as marginal soils due to their limited carrying capacity for rice (Oryza sativa L.) growth and production such as very low soil pH, high Fe content, and low soil nutrient content. A number of reclamation projects of ASS have not provided satisfactory outcomes due to a limited grasp of both the characteristics of the ASS and effective management methods. However, the precise cultivation system allows rice plants to grow well. The Banjarese-local rice cultivation system (BLRCS) is indigenous technology developed by Banjarese tribe in Kalimantan Island to enabling rice plant to grow and produce well in ASS. This review was addressed to provide scientifically describe and explain the chemical processes occurring in the soil under the BLRCS practice in ASS utilization for rice cultivation, consequently the utilization of ASS becomes more productive and environmentally friendly. The BLRCS is capable of enabling local rice plants to grow and produce well in ASS due to the improvement of ASS soil properties during growing season. Planting schedules were arranged based on the land hydrological conditions and use local rice varieties. The proper of land preparation and organic matter (OM) management in submerged condition during the growth and development stages of the rice plant lead Fe solubility becomes control, soil pH increase and nutrient in sufficient level for plant. [ABSTRACT FROM AUTHOR]

Background and Aims Many agricultural areas are expected to face hotter, drier conditions from climate change. Understanding the mechanisms that crops use to mitigate these stresses can guide breeding for more tolerant plant material. We tested relationships between traits, physiological function in hot conditions and historical climate associations to evaluate these mechanisms for winegrapes. We expected a more negative leaf osmotic potential at full hydration (π o), which reduces leaf turgor loss during drought, and either a metabolically cheaper or more osmoprotectant leaf chemical composition, to allow cultivars associated with hot, dry regions to maintain greater gas exchange in hot growing conditions. Methods We measured π o, gas exchange and leaf chemistry for seven commercially important winegrape cultivars that vary widely in historical climate associations. Vines were grown in common-garden field conditions in a hot wine-growing region (Davis, CA, USA) and measured over the hottest period of the growing season (July–September). Key Results The value of π o varied significantly between cultivars, and all cultivars significantly reduced π o (osmotically adjusted) over the study period, although osmotic adjustment did not vary across cultivars. The value of π o was correlated with gas exchange and climate associations, but in the direction opposite to expected. Photosynthesis and π o were higher in the cultivars associated with hotter, less humid regions. Leaf chemical composition varied between cultivars but was not related to climate associations. Conclusions These findings suggest that maintenance of leaf turgor is not a primary limitation on grapevine adaptation to hot or atmospherically dry growing conditions. Thus, selecting for a more negative π o or greater osmotic adjustment is not a promising strategy to develop more climate-resilient grape varieties, contrary to findings for other crops. Future work is needed to identify the mechanisms increasing photosynthesis in the cultivars associated with hot, dry regions. [ABSTRACT FROM AUTHOR]

Phenological shifts across plant species is a powerful indicator to quantify the effects of climate change. Today, mobile applications with automated species identification open new possibilities for phenological monitoring across space and time.Here, we introduce an innovative spatio‐temporal machine learning methodology that harnesses such crowd‐sourced data to quantify phenological dynamics across taxa, space and time. Our algorithm links individual phenological responses across thousands of species and geographical locations, using a similarity measure. The analysis draws on nearly ten million plant observations collected through the AI‐based plant identification app Flora Incognita in Germany from 2018 to 2021.Our method quantifies changes in synchronisation across the annual cycle. During the growing season, synchronised behaviour can be encoded by a few characteristic macrophenological patterns. Nonlinear spatio‐temporal changes of these patterns can be efficiently quantified using a data compressibility measure. Outside the growing season, the phenological synchronisation diminishes introducing noise into the patterns.Despite biases and uncertainties associated with crowd‐sourced data, for example due to human data collection behaviour, our study demonstrates the feasibility of deriving meaningful indicators for monitoring plant macrophenology from individual plant observations. As crowd‐sourced databases continue to expand, our approach holds promise to study climate‐induced phenological shifts and feedback loops. [ABSTRACT FROM AUTHOR]

Flavonoids are compounds that result from the secondary metabolism of plants and play a crucial role in plant development and mitigating biotic and abiotic stresses. The highest levels of flavonoids are found in legumes such as soybean. Breeding programs aim to increase desirable traits, such as higher flavonoid contents and vigorous seeds. Soybeans are one of the richest sources of protein in the plant kingdom and the main source of flavonoid derivatives for human health. In view of this, the hypothesis of this study is based on the possibility that the concentration of isoflavones in soybean seeds contributes to the physiological quality of the seeds. The aim of this study was to analyze the content of flavonoids in soybean genotypes and their influence on the physiological quality of the seeds. Seeds from thirty-two soybean genotypes were obtained by carrying out a field experiment during the 2021/22 crop season. The experimental design was randomized blocks with four replications and thirty-two F3 soybean populations. The seeds obtained were subjected to germination, first germination counting, electrical conductivity and tetrazolium vigor and viability tests. After drying and milling the material from each genotype, liquid chromatography analysis was carried out to obtain flavonoids, performed at UPLC level. Data were submitted to analysis of variance and, when significant, the means were compared using the Scott-Knott test at 5% probability. The results found here show the occurrence of genotypes with higher amounts of flavonoids when compared to their peers. The flavonoid FLVD_G2 had the highest concentration and differed from the others. Thus, we can assume that the type and concentration of flavonoids does not influence the physiological quality of seeds from different soybean genotypes, but it does indirectly contribute to viability and vigor, since the genotypes with the highest FLVD_G2 levels had better FGC values. The findings indicate that there is a difference between the content of flavonoids in soybean genotypes, with a higher content of genistein. The content of flavonoids does not influence the physiological quality of seeds, but contributes to increasing viability and vigor. [ABSTRACT FROM AUTHOR]

One of the frequently used drought metrics in scientific research is the consecutive dry days (CDDs) because it effectively indicates short‐term droughts important to ecosystems and agriculture. CDDs are expected to increase in many parts of the world in the future. In Serbia, both the frequency and severity of droughts have increased in recent decades, with most droughts being caused by a lack of precipitation during the warmer months of the year and an increase in evapotranspiration due to higher temperatures. In this study, the frequency and duration of extreme CDDs in the growing season in Serbia were analysed for the past (1950–2019) and the future (2020–2100) period. The Threshold Level Method over precipitation data series was used to analyse CDD events, where extreme CDDs are defined as at least 15 consecutive days without precipitation. In contrast to the original definition of the CDD as the maximum number of consecutive days with precipitation less than 1 mm, here we defined the threshold that is more suitable for agriculture because field crops can experience water stress after 15 days of no rainfall or irrigation. An approach for modelling the stochastic process of extreme CDDs based on the Zelenhasić–Todorović (ZT) method was applied in this research. The ZT method was modified by selecting a different distribution function for modelling the durations of the longest CDD events, enabling a more reliable calculation of probabilities of occurrences. According to the results, future droughts in Serbia are likely to be more frequent and severe than those in the past. The duration of the longest CDDs in a growing season will be extended in the future, lasting up to 62 days with a 10‐year return period and up to 94 days with a 100‐year return period. Results indicate a worsening of drought conditions, especially in the eastern and northern parts of Serbia. The results can help decision‐makers adapt agricultural strategies to climate change by providing information on the expected durations of extreme rainless periods in future growing seasons. Although the analysis was performed in Serbia, it can be applied to any other region. [ABSTRACT FROM AUTHOR]

Climate change and variability continue to affect crop production across the world in general and in Quebec in particular. Therefore, it is important to better understand this climate-yield nexus. Unfortunately, in Quebec, there are currently no studies that analyse both precipitation and barley yield. This study aims at filling this research gap by comparing standardised precipitation (SPI) against barley yield gaps across Quebec for three peripheral and three southern/central regions of Quebec. The study uses growing season precipitation data from Ouranos and barley yield data from Institut de la Statistique du Québec. This work deploys the use of standardised index (SPI) index and a machine learning yield gap algorithm (actual barley yield minus projected barley yield) to provide a provincial portrait of the relationships between SPI and barley yield. The results show that the peripheral regions record below zero SPIs (Abitibi-Temiscamingue − 0.48, Saguenay-Lac-Saint-Jean − 0.14 and Outaouais − 0.10) and more yield gap years, while the southern/central regions record positive SPIs (Estrie 1.17, Centre du Quebec 0.86 and Monteregie: 0.33) and fewer years with yield gaps. This shows that there is a south-north gradient in the variations of SPI and yield gaps. The SPI and yield patterns can be explained by prolonged winters further north of Quebec and recently winters with insufficient snow cover which triggers rapid snow melt and thus shortening the growing season for barley. Policy actions around drought-resistant varieties within a co-creation context and more research that explores daily and monthly liquid precipitation totals during the growing season of the crop need to be explored. There is also a need to better understand the economic costs and benefits of the associated yield gaps as well as the impacts of temperature. [ABSTRACT FROM AUTHOR]

As an ecologically sensitive area with significant desertification problems, the Ring-Tarim Basin has a fragile ecological environment that is vulnerable to both natural and anthropogenic factors. Accurate long-term vegetation observations are ecologically, socially, and economically important for desertification control. In this study, based on the ground-measured data and the fractional vegetation cover (FVC) inversion dataset obtained by the image element dichotomy method, we used the methods of slope-trend analysis and multiple-regression residual analysis to analyze the spatial and temporal characteristics of the vegetation cover in the desertified area of the Ring-Tarim Basin. At the same time, we assessed the impacts of climate change and human activities on vegetation changes and the contribution of driving forces. The results showed that (1) The annual mean value of FVC in the growing season in the Ring-Tarim Basin generally showed a fluctuating and increasing trend during the period of 1993–2021; a decreasing trend during 1993–1999, with a change rate of −0.13 × 10−2a−1; and the fastest increasing trend during 2010–2021, with a change rate of 0.23 × 10−2a−1. (2) The effects of climate change and human activities on FVC changes in the growing season had great spatial heterogeneity. The areas where climate change and human activities had no significant effect on FVC changes in the growing season accounted for 86.25% and 77.91%, respectively, the areas where climate and human activities promoted FVC increase in the growing season accounted for 10.53% and 16.37%, respectively, and the areas where climate and human activities inhibited FVC increase in the growing season accounted for 3.22% and 5.72%, respectively. (3) About 76.9% of the FVC changes in the area around the Ring-Tarim Basin were caused by climate change and human activities. In addition to the eastern part of the study area, the vegetation cover of the oases in the west, north, and south generally showed an increasing trend, and the increasing area was proportional to the distribution density of the oasis cities. The trend of vegetation change in the area of the oasis and the fringes of the oasis was drastic. The contribution and inhibition of human activities to FVC, and the driving force of FVC change were greater than that of climate change. More than half of the area had an anthropogenic contribution of more than 60%, indicating that China's ecological projects have had a significant effect on vegetation change in the extreme arid regions. [ABSTRACT FROM AUTHOR]

Phenology is a critical mirror reflecting vegetation growth and has a major impact on terrestrial ecosystems. The Loess Plateau (LP) is a paramount ecological zone in China that has experienced considerable vegetation changes. However, understanding the dynamics of vegetation phenology is limited by ambiguous vegetation interpretation and anthropogenic-induced forces. This study combined the multi-climatic and anthropogenic datasets to characterize the interactions between phenology shifts and environmental variables. The principal findings were as follows: (1) Phenological shifts exhibit spatial heterogeneity and an interannually increasing trend in greenness (R2 > 0.6, p < 0.05). Notably, SOS (the start of the growing season) advances while EOS (the end of the growing season) delays in both the southeastern and northwestern regions. (2) SOS and EOS, primarily in the range of 100–150 and 285–320 days, respectively. Phenological changes vary depending on vegetation types. The forest has an early SOS, within 80–112 days, and a delayed EOS, within 288–320 days. The SOS of shrub is mainly within 80–144 days. (3) EOS shows a strong response to the preseason of each climate variable. Precipitation (R = 0.76), soil moisture (R = −0.64), and temperature (R = 0.89) are the governing determinants in shaping vegetation phenology. In addition, agriculture and urbanization play a significant role in shaping the spatial variations of SOS. These findings provide a basis for a systematic understanding of the processes that affect vegetation growth, which is crucial for maintaining the health and sustainability of arid and semiarid ecosystems. [ABSTRACT FROM AUTHOR]

Beaver‐based restoration techniques seek to assist with the recovery of stream systems that have been damaged, degraded, or destroyed. In addition to reintroducing beaver, restoration practitioners have sought to mimic the influence of beaver dams on stream processes by building beaver dam analogs (BDAs). Stream restoration has been criticized for a lack of extended monitoring and a dearth of empirical evidence for the efficacy of BDAs. Here, we extend early and previously reported 1‐ to 2‐year monitoring of five BDAs on a low‐gradient stream lacking woody riparian vegetation to 3–6 years, depending on the parameter examined. BDAs raised groundwater near the stream and did not affect water temperatures during the duration of monitoring. Consistent with elevated groundwater levels, riparian willow cuttings grew 2.8–9.6 times more when planted near BDAs than far from BDAs, which was more than the 1.3‐ to 1.4‐fold difference after the first growing season. In contrast, a short‐term association between BDAs and willow survival disappeared in the long term. Likewise, sediment aggradation above the upstream BDA 1 year after construction reversed completely 4 years later, probably due to structural damage during high flows that could not be repaired until flows abated. Annual peak flow levels explained over 80% of the variation in the number of structures requiring annual repair. Our results suggest that BDA‐based restoration should account for both the costs of structure maintenance during project planning and the importance of long‐term monitoring during project assessment. [ABSTRACT FROM AUTHOR]

Myochrous armatus Baly, 1865 (Coleoptera: Chrysomelidae) has expanded its occurrence significantly into soybean‐growing areas of Brazilian Cerrado and became an important early‐season soil pest. Experiments were performed under field conditions from 2020 to 2023 to assess several aspects: (1) population behaviour over crop season and offseason; (2) day/night behaviour during the early stages of soybean plants and (3) injury to plants and potential damage to soybean yield to establish the Economic Injury Level (EIL). Adults of the M. armatus population presented a season‐long abundance during the specific period from late October to January, with major captures in November and December (end of Spring), either inside or on the edge of soybean fields. Weeds and volunteer plants of corn and cotton hosts adults and eggs. These findings suggest an univoltine life cycle. Behavioural assessments revealed that M. armatus does not exhibit a specific day, night or crepuscular behaviour, performing deeds at any time. The majority of insects (40% to 70%) were found in the soil throughout the day and night. Adults feed on soybean plants by scraping or cutting the stem, cotyledon, petiole and apical sprouting. Their preference is initially for the stem and cotyledon (up to 14 days after emergence), and later for the petiole (after 21 days of emergence). After 7 days of coexistence at V1‐V3 soybean stages, we observed a potential yield reduction of 35% for each insect per plant. Dynamic EIL estimations are between 0.4 and 1.9 adults per row metre, depending on the grower productivity expectation, control costs and soybean market value. Our results are fundamental for establishing Integrated Pest Management for M. armatus in soybean and other crop systems. [ABSTRACT FROM AUTHOR]

The insectivorous Northern Pitcher Plant, Sarracenia purpurea, recruits a dynamic biotic community in the rainwater collected by its pitcher-shaped leaves. Insect capture and degradation within the pitcher fluid (phytotelma) has been well documented as a mechanism for supplementing the plant's nitrogen, phosphorous, and micronutrient requirements. Metagenomic studies have shown a diverse microbiome in this phytotelm environment, including taxa that contribute metabolically to prey digestion. In this investigation, we used high-throughput 16S rDNA sequencing and bioinformatics to analyze the S. purpurea phytotelm bacteriome as it changes through the growing season (May–September) in plants from the north-central region of the species' native range. Additionally, we used molecular techniques to detect and quantify bacterial nitrogenase genes (nifH) in all phytotelm samples to explore the hypothesis that diazotrophy is an additional mechanism of supplying biologically available nitrogen to S. purpurea. The results of this study indicate that while prokaryote diversity remains relatively stable in plants at different locations within our region, diversity changes significantly as the growing season progresses. Furthermore, nifH genes were detected at biologically significant concentrations in one hundred percent of samples, suggesting that nitrogen fixation may be an important contributor to the S. purpurea nutrient budget. [ABSTRACT FROM AUTHOR]

In order to gain a deeper understanding of the effects of environmental factors on the formation of Populus euphratica xylem, this study analysed the anatomical characteristics of Populus euphratica xylem and its response to environmental factors using wood anatomy as an example of Populus euphratica in the Yingsu section of the lower Tarim River. The results showed the following: (1) Throughout the growing season, the number of conduits of Populus euphratica in the two sample sites showed a slow increasing trend with the increase in groundwater burial depth, and the total conduit area showed an increasing and then decreasing trend with the increase in groundwater burial depth. The four indices of total, minimum, average, and maximum conduit areas in Populus euphratica xylem increased significantly with increasing temperatures during the growing season. (2) From the principal component analysis, the anatomical parameters of Populus euphratica xylem were found to be positively correlated with the depth of groundwater, average air temperature, maximum air temperature, minimum air temperature, surface temperature, relative humidity, and saturated water and air pressure deficit in the two sampling sites The most significant effects were found in the air temperature and depth of the groundwater. (3) The contribution of groundwater level and air temperature to different growth stages of Populus euphratica xylem was different. During the early part of the growing season of Populus euphratica, the air temperature was the main factor influencing the number of xylem conduits and total conduit area. As the growing season entered the middle stage, the air temperature and groundwater together affected the conduit parameters. In the later part of the growing season, groundwater became the most important factor affecting the number of conduits and the total conduit area. (4) The sensitivity analyses yielded a sensitive groundwater burial depth of 5.2 m for changes in the number of conduits in the xylem of the Populus euphratica and 5.9 m for changes in the total conduit area; the sensitive air temperature for the total conduit area in the xylem of the Populus euphratica was 22.0 °C, and the sensitive air temperature for the average conduit area was 18.5 °C. The results of this study can have important theoretical significance for understanding the Populus euphratica forests, as well as ecological water resource management in the lower Tarim River. They also provide scientific basis for the restoration and protection of Populus euphratica forests in the lower Tarim River. [ABSTRACT FROM AUTHOR]

Girdling is often used as an experimental method to study source/sink controls of cambial growth. However, the phloem responses to girdling have not been well investigated. The aim of this research was to characterize the anatomical changes in the phloem and xylem of different species following trunk girdling. Different species of gymnosperm (Abies sibirica, Pinus sylvestris) and angiosperm (Alnus incana, Populus tremula) woody plants were selected. We girdled trunks during active growth and sampled tissues at two levels (1 cm and 35 cm) above the girdle at the end of the growing season. General responses to girdling were recorded for the studied species, such as increased phloem increments, parenchymatization of conducting tissues, reduction in the size of conducting elements, and an increase in the size of axial parenchyma cells in the phloem and xylem. We observed the suppression of xylogenesis in 3 out of 4 species. Differences in the structure of conducting tissues were found, which are due to species differences in the initial tissue structure. In gymnosperms, noticeable differences in the number of resin ducts in the xylem were observed between control and girdled trees. In angiosperms, we found the formation of cells with thickened cell walls in girdled trees (i.e., the formation of phloem and xylem fibers with thickened cell walls in aspen and sclereids in the phloem of alder). Based on the literature data, the observed responses may be due to both the wounding effect and the influence of the high sugar content above the girdle. [ABSTRACT FROM AUTHOR]

The rare and threatened Heliosciadium repens grows in moist grasslands and has a distinct life cycle. Plants reproduce both clonally, although ramets tend to be short‐lived, and sexually, with seeds that can form a persistent soil seed bank. The germination requirements of H. repens were investigated, yielding important information for its habitat management and conservation. We examined the soil seed bank in three populations and carried out germination experiments and embryo growth measurements with fresh seeds in laboratory, greenhouse and outdoor conditions. We also investigated the effects of storage and burial of seeds. H. repens formed a long‐term persistent (>6 years) soil seed bank with very pronounced primary dormancy, but no secondary dormancy or dormancy cycles. Seeds can germinate throughout the growing season when temperatures are sufficiently high. Embryo growth and seed germination are triggered by light and, to a lesser extent, daily temperature fluctuations. Seeds of H. repens seem to have developed a unique germination syndrome with several strategies to remain dormant in the soil until optimal conditions are present for seedling establishment and survival. Both sexual reproduction and seed bank formation are crucial for the long‐term survival of the populations. [ABSTRACT FROM AUTHOR]

Yield and its components are greatly affected by climate change. Adjusting the sowing date is an effective way to alleviate adverse effects and adapt to climate change. Aiming to determine the optimal sowing date of summer maize and clarify the contribution of climatic variables to grain yield and its components, a consecutive 4-year field experiment was conducted from 2016 to 2019 with four sowing dates at 10-day intervals from 5 June to 5 July. Analysis of historical meteorological data showed that more solar radiation (SR) was distributed from early June to mid-August, and the maximum temperature (Tmax) > 32°C appeared from early July to late August, which advanced and lasted longer in 1991–2020 relative to 1981–1990. Additionally, the precipitation was mainly distributed from early June to late July. The climate change in the growing season of summer maize resulted in optimal sowing dates ranging from 5 June to 15 June, with higher yields and yield stability, mainly because of the higher kernel number per ear and 1,000-grain weight. The average contribution of kernel number per ear to grain yield was 58.7%, higher than that of 1,000-grain weight (41.3%). Variance partitioning analysis showed that SR in 15 days pre-silking to 15 days post-silking (SS) and silking to harvest (SH) stages significantly contributed to grain yield by 63.1% and 86.4%. The extreme growing degree days (EDD) > 32°C, SR, precipitation, and diurnal temperature range (DTR) contributed 20.6%, 22.9%, 14.5%, and 42.0% to kernel number per ear in the SS stage, respectively. Therefore, we concluded that the early sowing dates could gain high yield and yield stability due to the higher SR in the growing season. Meanwhile, due to the decreasing trend in SR and increasing Tmax trend in this region, in the future, new maize varieties with high-temperature resistance, high light efficiency, shade tolerance, and medium-season traits need to be bred to adapt to climate change and increased grain yield. [ABSTRACT FROM AUTHOR]

Little is known about how carbon integration and storage dynamics affect and are affected by demography in field populations. We sought to elucidate this link by examining dynamic patterns of carbon integration relative to the timing of demographically significant developmental decisions regarding shoot type determination in mayapple, Podophyllum peltatum, a clonal plant with large and persistent rhizomes. Individual rhizome systems growing in natural populations were fed 14CO2 either in late-April, early-May, or mid-June, then harvested at intervals throughout the current season and into the next. When distribution of label was examined we found that carbon fixed at different times in the growing season is used differently: April-fixed assimilate remained in the labeled shoot or was moved into the old rhizome, May-fixed assimilate was found predominantly in the old rhizome, while early-June fixed assimilate moved into the old rhizome and the extending new ramet. Movement of assimilate into the old rhizome appeared to have precedence over formation of additional new ramets. Despite significant within season changes in location of dominant sinks within rhizome systems, there was little redistribution of labeled assimilate: early fixed assimilate was not used to fuel later within season growth, however, assimilate was redistributed between seasons. Vegetative and sexual systems differed in the distribution only of April-fixed assimilate. This was observed even though early labeling occurred prior to anthesis. Sexual systems retained a greater proportion of assimilate in the stem than did vegetative ones, which exported more to the old rhizome. 14C-distribution patterns did not vary between systems differing in future demographic status suggesting that the developmental decision regarding shoot type is based on resources acquired in prior years. We explore the hypothesis that preformation and storage are functionally linked traits that permit plants to coordinate the developmental determination of structures differing in cost and demographic function with known resource status. We conclude that demography influences and is influenced by integrative physiology and that physiological restrictions on within season redistribution of assimilates constrain plants' capacities to respond to short-term environmental variation. Such constraints may affect plants' abilities to respond to rapid environmental change in the Anthropocene. [ABSTRACT FROM AUTHOR]

Plants exhibit an array of drought responses and adaptations, where the trade-off between water loss and CO2 uptake for growth is mediated by regulation of stomatal aperture in response to soil water content (SWC), among other factors. For crop yield stability, the question is how drought timing and response patterns relate to post-drought growth resilience and vigor. We earlier identified, in a few reference varieties of barley that differed by the SWC at which transpiration was curtailed, two divergent water use strategies: water-saving ("isohydric") and water-spending ("anisohydric"). We proposed that an isohydric strategy may reduce risk from spring droughts in climates where the probability of precipitation increases during the growing season, whereas the anisohydric is consistent with environments having terminal droughts, or with those where dry periods are short and not seasonally progressive. Here, we have examined drought response physiology in an 81-line barley (Hordeum vulgare L.) diversity set that spans 20th century European breeding and identified several lines with a third, dynamic strategy. We found a strong positive correlation between vigor and transpiration, the dynamic group being highest for both. However, these lines curtailed daily transpiration at a higher SWC than the isohydric group. While the dynamic lines, particularly cv Hydrogen and Baronesse, were not the most resilient in terms of restoring initial growth rates, their strong initial vigor and high return to initial transpiration rates meant that their growth nevertheless surpassed more resilient lines during recovery from drought. The results will be of use for defining barley physiological ideotypes suited to future climate scenarios. [ABSTRACT FROM AUTHOR]

Seaweed functional traits provide insights on natural populations, their adaptations to the local environment, which can be utilized for commercial exploitation. Here, we analyzed the functional traits of Gracilaria dura from two intertidal populations in Veraval and Adri, from the coast of Gujarat, India, over a period of three months. Functional traits were measured by analyzing growth rates, respiration, primary production, antioxidant activity and the content of plant growth hormones. The weight-to-length allometric exponent ≈3 indicated that G. dura grew almost isometrically. Furthermore, frond shape was not significantly different. Fronds in Veraval, resting submerged, grew faster than the fronds in Adri, which, lay exposed in the flat bare rock during low tide. Accordingly, the simultaneous increase in antioxidant activity, O2 production and chlorophyll content in fronds from Adri suggests that stress from desiccation and UV led to the detrimental accumulation of Reactive Oxygen Species, leading to decreased growth and decreased production of growth hormones. The increased Chl-a may indicate enhanced non-photochemical quenching (NPQ) for the dissipation of excess absorbed light. These results aid in establishing the best practices for maximizing biomass yield or the yield of specific molecules. For maximized biomass yield, fronds should not be subject to emersion nor cultivated on the sea-surface. On the other hand, fronds grown subject to emersion or at the sea-surface yield less biomass but more content on molecules such as antioxidants (flavonoids, phenolics, enzymes), that fight stress from desiccation high temperatures and UV. In this case, stress should still be avoided during the initial growth, at the onset of the growth season, in order to not disrupt the production of growth hormones. The increased O2 production at Adri was initially mistakenly perceived as enhanced Net Primary Production. Only a posterior holistic perspective over the whole data allowed to conclude that it was likely the stress-induced detrimental accumulation of Reactive Oxygen Species. More robust experiments are required to establish if the differences observed between locations have led to the evolution of genetic strains specific to each habitat that may show different performances and yields when cultivated in similar environments. [ABSTRACT FROM AUTHOR]

Soil water balance calculation is one of the methods used to estimate the dynamics of soil water content during plant growth. This study aims to describe rainfall conditions and analyze soil water balance as well as determine the growing season and composition of food crop combination patterns based on the available growing season in East Seram Island. This research uses rainfall data for 30 years of observation period 1992-2021 from Geser Meteorological Station (Data analysis with the following stages: (i) rainfall analysis (ii) calculation of average rainfall (iii) determination of rainfall with a 75% chance (iv) calculation of soil water balance using the Thornthwaite and Mather method (v) determination of the growing season and cropping pattern. The results showed that the average rainfall in East Seram was 2,194 mm/year with a water deficit (D) occurring in October and November, then the rainfall had a 75% chance of being exceeded at 1,439 mm/year with a water deficit of 228 mm/year which lasted for eight months, namely August - March. The growing season under normal rainfall conditions was available throughout the year, while under high rainfall conditions, a 75% chance of the growing season was available for five months, namely May and October. The cropping patterns and crop combinations used were monoculture, polyculture, and intercropping with combinations of cassava, maize, sweet potato, groundnut, mung bean, cassava-corn, cassava-peanuts/green beans, maize-peanuts, cassava-corn-peanuts/green beans, cassava-corn-horticultural crops. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare Fe, Zn, Mn, Al and Li contents in table potato tubers, obtained from seven potato cultivars with different flesh colour, and one cultivar characterised by light-coloured flesh. The study material consisted of potato tubers produced in a one-factor field experiment carried out at the Agricultural Experimental Station in Zawady belonging to the University of Siedlce, Poland (52°03′ N, 22°33′ E) in 2021–2023. The following cultivars were tested: Eurostar (light yellow flesh), Rote Emmalie and Herbie 26 (red flesh), Provita, Salad Blue, Blaue Annelise, Vitelotte Noire and Bora Valley (purple and blue flesh). The study showed that the genetic characteristics of the cultivars determined the nutrient content and uptake with tuber yield. Of the tested minerals which are important for human nutrition (Fe, Zn, Mn), red and purple cultivars accumulated more Fe than the light yellow-fleshed Eurostar. Zn content was the highest in red-fleshed cultivars compared with light and purple-fleshed cultivars. Mn content was the highest in the tubers of the light yellow-fleshed Eurostar and lowest in red Rote Emmalie. Fe, Zn, Mn and Al contents and uptake with tuber yield were influenced by weather conditions during the growing season. [ABSTRACT FROM AUTHOR]

The winged bean is only one of the members of the leguminous species that has the potential for duo-purpose for its pod and tuber yields. The protein and nutritional content in the tuber can be used as alternative crops for animal feed. Previous studies identified the winged bean varieties as having high potential for tuber production, although their tuber development remains unclear. This study aims to elucidate the development of winged bean tubers based on their size and weight during eight months of growth. Tuber yields of high-potential winged bean varieties (W018 and W099) were compared to commercial varieties (Ratchaburi) under field conditions over two years. The experiments were laid out in randomized complete block design with three replications in the 2021–2022 and 2022–2023 growing seasons. The tuber formation of winged bean exhibited a significant increase in tuber weight and size in the fourth month of growth in all varieties, with a gradual change from fibrous roots to tubers. Particularly in the W018 and W099 varieties, tuber development persisted up to eight months after transplanting. On the other hand, the Ratchaburi variety had small tuber size, resulting in the tubers weighing less than in the W018 and W099 varieties. The results indicated that winged bean varieties had different tuber development, with the W018 and W099 varieties being suitable for tuber harvesting at eight months. The large tuber size can be an appropriate alternative to animal feed materials. At the same time, the Ratchaburi variety requires only five months since it is cultivated primarily for tuber consumption, which is concerned with size and shape. Moreover, the yields of the W018 and W099 varieties were significantly higher compared to Ratchaburi at 22.4, 19.3, and 7.423 T/ha in the 2021–2022 growing season and 8.4, 7.9, and 5.6 T/ha in the growing season of 2022–2023, respectively. The protein content in the winged bean tubers increased to 13.00% at eight months. The years (Y) and genotypes (G) differed considerably for tuber formation. The variation in both Y and G and the shoot/root ratio are also discussed in this study. [ABSTRACT FROM AUTHOR]

Drip irrigation with saline water is frequently adopted to realize the sustainable utilization of saline–sodic soil with high water tables, and soil enzyme activities can be used to indicate changes in soil quality. In the current study, spatiotemporal changes in soil urease enzyme (URE), alkaline phosphatase (ALP) and invertase (INV) activities were investigated during consecutive growing seasons. Soil in beds was sampled before planting (0 y) and one, two, three and four years after the growing season (1 y, 2 y, 3 y, 4 y), and these samples were distributed at four horizontal distances from the drip line (0, 10, 20 and 30 cm) and four vertical soil depths (0–10, 10–20, 20–30 and 30–40 cm). The results showed that a distribution pattern of URE and ALP activities formed during the first growing season, while the distribution of INV activity formed until the third growing season. All three soil enzyme activities in the upper soil layers and positions close to the drip line were more greatly affected by planting year. The average URE activity of the soil profile decreased slightly during the first year and increased by about 220% and decreased by 20% after reclamation for two and three years, and finally, it increased to 4.9 μg NH4+·g−1·h−1 at the end of the fourth growing season. ALP activity remained stable during the first two years and rapidly increased in the following years; in particular, in the fourth year, it reached 32.7 μg ph(OH)·g−1·h−1. INV activity increased continually with the number of years after planting and reached 1009.0 μg glu·g−1·h−1 at the fourth season's end. An analysis of variance indicated that URE, ALP and INV activities varied insignificantly among the time points of 0 y, 1 y, 2 y and 3 y (p < 0.05), while they were significantly higher for 4 y than for 0 y and 1 y. In addition, all three enzyme activities of the soil profile had an exponentially increasing trend with the number of years after planting. These results indicated the soil quality in saline–sodic soils could be improved with time under drip irrigation with local saline groundwater, especially around the drip line. [ABSTRACT FROM AUTHOR]

Simple Summary: Our research is the first comparative field-based study on (i) the above- and belowground population dynamics and seasonal abundance and (ii) the effectiveness of conventional and innovative sampling methods for two mealybug species, Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Coccomorpha, Pseudococcidae) and Heliococcus summervillei (Brookes, 1978) (Hemiptera: Coccomorpha, Pseudococcidae), in commercial sugarcane (Saccharum sp. hybrids) (f. Poaceae) over consecutive growing seasons. The novel description of S. sacchari and H. summervillei on sugarcane in multiple seasons, along with the best sampling techniques, allows for accurate monitoring and comparison within the Pseudococcidae family, thus aiding the ability to monitor the pest status in commercial sugarcane. This research is focused on a comparative field-based study of the population dynamics and sampling methods of two mealybug species, Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Coccomorpha, Pseudococcidae) and Heliococcus summervillei (Brookes, 1978) (Hemiptera: Coccomorpha, Pseudococcidae), in sugarcane (Saccharum sp. hybrids) (f. Poaceae) over consecutive growing seasons. The research monitored and compared the above- and belowground populations and seasonal abundance of these two mealybug species in sugarcane fields in Far North Queensland, with non-destructive sampling techniques of yellow sticky traps, pan traps, and stem traps, and destructive sampling of the whole leaf and whole plant. The results indicated that S. sacchari (n = 29,137) was more abundant and detected throughout the growing season, with population peaks in the mid-season, while H. summervillei (n = 2706) showed peaks of the early-season activity. S. sacchari is primarily located on sugarcane stems and roots, compared to H. summervillei, which is located on leaves and roots. The whole-leaf collection and stem trap were the most effective sampling techniques for quantification of H. summervillei and S. sacchari, respectively. This study enhanced the understanding of S. sacchari and the first-ever record of H. summervillei on sugarcane in Australia and will contribute to the development of more effective pest management strategies. [ABSTRACT FROM AUTHOR]

Vegetation autumn phenology is critical in regulating the ecosystem carbon cycle and regional climate. However, the dominant drivers of autumn senescence and their temporal shifts under climate change remain poorly understood. Here, we conducted a multi‐factor analysis considering both direct climatic controls and biological carryover effects from start‐of‐season (SOS) and seasonal peak vegetation activities on the end‐of‐season (EOS) to fill these knowledge gaps. Combining satellite and ground observations across the northern hemisphere, we found that carryover effects from early‐to‐peak vegetation activities exerted greater influence on EOS than the direct climatic controls on nearly half of the vegetated land. Unexpectedly, the carryover effects from SOS on EOS have significantly weakened over recent decades, accompanied by strengthened climatic controls. Such results indicate the weakened constraint of leaf longevity on senescence due to prolonged growing season in response to climate change. These findings underscore the important role of biological carryover effects in regulating vegetation autumn senescence under climate change, which should be incorporated into the formulation and enhancement of phenology modules utilized in land surface models. [ABSTRACT FROM AUTHOR]

Climate change in high latitude regions leads to both higher temperatures and more precipitation but their combined effects on terrestrial ecosystem processes are poorly understood. In nitrogen (N) limited and often moss‐dominated tundra and boreal ecosystems, moss‐associated N2 fixation is an important process that provides new N. We tested whether high mean annual precipitation enhanced experimental warming effects on growing season N2 fixation in three common arctic‐boreal moss species adapted to different moisture conditions and evaluated their N contribution to the landscape level. We measured in situ N2 fixation rates in Hylocomium splendens, Pleurozium schreberi and Sphagnum spp. from June to September in subarctic tundra in Sweden. We exposed mosses occurring along a natural precipitation gradient (mean annual precipitation: 571–1155 mm) to 8 years of experimental summer warming using open‐top chambers before our measurements. We modelled species‐specific seasonal N input to the ecosystem at the colony and landscape level. Higher mean annual precipitation clearly increased N2 fixation, especially during peak growing season and in feather mosses. For Sphagnum‐associated N2 fixation, high mean annual precipitation reversed a small negative warming response. By contrast, in the dry‐adapted feather moss species higher mean annual precipitation led to negative warming effects. Modelled total growing season N inputs for Sphagnum spp. colonies were two to three times that of feather mosses at an area basis. However, at the landscape level where feather mosses were more abundant, they contributed 50% more N than Sphagnum. The discrepancy between modelled estimates of species‐specific N input via N2 fixation at the moss core versus ecosystem scale, exemplify how moss cover is essential for evaluating impact of altered N2 fixation. Importantly, combined effects of warming and higher mean annual precipitation may not lead to similar responses across moss species, which could affect moss fitness and their abilities to buffer environmental changes. [ABSTRACT FROM AUTHOR]

Accurate monitoring of leaf phenology, from individual trees to entire ecosystems, is vital for understanding and modeling forest carbon and water cycles, as well as assessing climate change impact. However, the accuracy of many remote-sensing phenological products remains difficult to directly corroborate using ground-based monitoring, owing to variations in the observed indicators and the scales used. This limitation hampers the practical implementation of remote-sensing phenological metrics. In our study, the start of growing season (SOS) from 2016 to 2021 was estimated for the continental USA using Sentinel-2 images. The results were then matched with several ground-based spring vegetation phenology metrics obtained by the USA National Phenology Network (USA-NPN). In this study, we focused on the relationships between the leaf-unfolding degree (LUD), the SOS, and the factors that drive these measures. Our results revealed that: (1) the ground-based leaves and increasing leaf size stages were significantly correlated with the SOS; (2) with the closest match being observed for a leaf spread of 13%; (2) the relationship between the SOS and LUD varied according to the species and ecoregion, and the pre-season cumulative radiation was found to be the main factor affecting the degree of matching between the ground observations and the metrics derived from the Sentinel-2 data. Our investigations provide a ground-based spring phenology metric that can be used to verify or evaluate remote-sensing spring phenology products and will help to improve the accuracy of remote-sensing phenology metrics. [ABSTRACT FROM AUTHOR]

Biophysical variables play a crucial role in understanding phenological stages and crop dynamics, optimizing ultimate agricultural practices, and achieving sustainable crop yields. This study examined the effectiveness of the Sentinel-2 Biophysical Processor (S2BP) in accurately estimating crop dynamics descriptors, including fractional vegetation cover (FVC), leaf area index (LAI), leaf chlorophyll a and b (LCab), and canopy water content (CWC). The evaluation was conducted using estimation quality indicators (EQIs) and comprehensive ground throughout the entire growing season at the field scale. To identify soil and vegetation pixels, the spectral unmixing technique was employed. According to the EQIs, the best retrievals were obtained for FVC in around 99.9% of the 23,976 pixels that were analyzed during the growth season. For LAI, LCab, and CWC, over 60% of the examined pixels had inputs that were out-of-range. Furthermore, in over 35% of the pixels, the output values for LCab and CWC were out-of-range. The FVC, LAI, and LCab estimates agreed well with ground measurements (R2 = 0.62–0.85), whereas a discrepancy was observed for CWC estimates when compared with ground measurements (R2 = 0.51). Furthermore, the uncertainties of FVC, LAI, LCab, and CWC estimates were 0.09, 0.81 m2/m2, 60.85 µg/cm2, and 0.02 g/cm2 through comparisons to ground FVC, LAI, Cab, and CWC measurements, respectively. Considering EQIs and uncertainty metrics, the order of the estimation accuracy of the four variables was FVC > LAI > LCab > CWC. Our analysis revealed that temporal variations of FVC, LAI, and LCab were primarily driven by field-scale events like sowing date, growing period, and harvesting time, highlighting their sensitivity to agricultural practices. The robustness of S2BP results could be enhanced by implementing a pixel identification algorithm, like embedding spectral unmixing. Overall, this study provides detailed, pixel-by-pixel insights into the performance of S2BP in estimating FVC, LAI, LCab, and CWC, which are crucial for monitoring crop dynamics in precision agriculture. [ABSTRACT FROM AUTHOR]

Plants seeded in degraded grasslands often fail to establish. In the Northern Great Plains, perennial cool‐season grasses are easiest to establish, and they sometimes competitively suppress warm‐season grasses, shrubs, and forbs. Seeding cool‐season grasses at low rates sometimes benefits other seeded plants but risks greater weed abundances. To identify grass seed rates low enough to allow other plants to establish but high enough to constrain weeds, we varied cool‐season grass seed rates while holding warm‐season grass, shrub, and forb seed rates fixed. The first couple growing seasons after seeding, we hypothesized cover of other seeded plants and weeds would decrease with increasing cool‐season grass seed rate. During later growing seasons, we hypothesized weed cover would become independent of grass seed rates due to seeded plants increasing in plots seeded at low rates. Neither hypothesis was supported. Because weed abundances were high, warm‐season grasses, shrubs, and forbs apparently experienced similarly intense competition regardless of grass rate, so low rates did not increase seeded plant establishment. Regardless of seed rate, cool‐season grass cover did not increase between the second and final (i.e. fourth) growing season, perhaps because of low precipitation. Increasing warm‐season grass, shrub, and forb abundances will require controlling weeds in addition to lowering cool‐season grass seed rates. Even these steps will not always increase establishment because native plants sometimes died before controlling weeds with herbicides became feasible and grass competition became important. Lowering grass rates without implementing weed control risks sites becoming weedy for prolonged periods. [ABSTRACT FROM AUTHOR]