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As essential environmental parameters in the greenhouse, appropriate light and CO2 will improve agricultural productivity and quality. Although many related studies have been carried out on the intelligent regulation of these environmental factors, the regulation of light and CO2 is usually controlled separately, and energy consumption is rarely considered. This paper proposed a coordinated control strategy for greenhouse light and CO2 based on the multi-objective optimization model. Firstly, the experiments on the net photosynthetic rate of blueberry under different temperatures, photon flux density, and CO2 concentration nesting were carried out to establish a blueberry net photosynthetic rate prediction model based on Support Vector Regression (SVR). Secondly, a model for calculating the energy cost of both light and CO2 was constructed. Thirdly, taking the maximum net photosynthetic rate and the minimum energy cost as the objective functions, the Non-dominated Sorting Genetic Algorithm (NSGA-II) was leveraged to obtain the Pareto optimal solutions of the target regulation values of light and CO2 concentration in different temperature ranges. Then, the optimal values were selected based on two different strategies. Finally, the multi-objective optimal control strategy proposed in this paper was compared with both the classical threshold control strategy and the Gaussian curvature maximization control strategy. The results indicated that the strategy which prioritized energy saving could reduce the energy cost by about 22.33% and 19.08%, respectively, under the premise that the net photosynthetic rate was consistent. Meanwhile, the strategy that prioritized production efficiency could increase the net photosynthetic rate by about 8.40% and 4.42%, respectively, with the same energy cost. In conclusion, the proposed multi-objective optimization control can improve the greenhouse climate control performance and reduce cost compared with other mentioned strategies. [ABSTRACT FROM AUTHOR]

The current scientific literature predominantly focuses on pilot-scale studies concerning the effectiveness of membrane covers in reducing gas emissions during cattle manure composting. Our study centers on the application of a leading market commercial membrane cover (ePTE-TEXcomm) and a locally manufactured one (ProfiCover®) at industrial processing levels, evaluating their efficacy in mitigating gas emission during the fifth day of the thermophilic phase. Taking into account material inhomogeneities, work environment impact, and efficiency, the results are characteristic of industrial-scale processes rarely discussed in the scientific literature. Our results, obtained with a portable gas sampler and FTIR spectroscopy measurements using corresponding standards, indicate that ePTE-TEXcomm manifested a reduction of 90.8% for NH3 and 59.6% for CO2. CH4 emissions increased, suggesting their potential entrapment. N2O and propane equivalent experienced reductions of 23.1% and 44.8%, respectively. On the other hand, ProfiCover® presented emission reductions for NH3 and CO2 of 93.3% and 85.9%, respectively. CH4, contrasting with ePTE-TEXcomm, showed a significant reduction of 55.6%. N2O and propane equivalent followed with reductions of 56.7% and 84.5%, respectively. All of this divergence in performance implies a potential trade-off in emission reduction efficacy between the covers. Knowledge sharing between researchers and industry partners is key to translating these technologies into widespread adoption. [ABSTRACT FROM AUTHOR]

The increasing CO2 concentration ([CO2]) in the atmosphere decreases mineral nutrients concentration in crops, whereas it increases water use efficiency (WUE). Partial root-zone irrigation (PRI) could not only increase WUE but also improve plant nutrient status. Yet the effect of PRI combined with elevated CO2 concentration (e[CO2]) on the element stoichiometry of tomato leaves remains unknown. This study sought to investigate the responses of leaf mineral nutrients status and element stoichiometric ratios in tomatoes to PRI combined with e[CO2]. Tomato plants (cv. Ailsa Craig) were grown in pots in climate-controlled growth chambers with ambient [CO2] (a[CO2], 400ppm) and elevated [CO2] (e[CO2], 800ppm), respectively. Three irrigation regimes, i.e., full irrigation (FI), deficit irrigation (DI) and PRI, were applied to tomato plants at the flowering stage. The results showed that plants grown under DI and PRI had a similar biomass, enhanced root growth including greater root to shoot ratio, root length, surface area, volume and specific length, and an improved WUE in comparison with FI under e[CO2]. Additionally, under e[CO2], PRI showed an increase in leaf [C](+1.5%) and [N] (+9.3%), no decrease in leaf [K], [Ca], [Mg], [S] and [15N], but a decrease in leaf C/N (−6.6%) as compared with FI. Conclusively, PRI had the ability to improve leaf N concentration, maintain most leaf mineral nutrient concentrations, and optimize or maintain leaf element stoichiometric ratios under e[CO2]. Therefore, PRI would be a practicable mode of irrigation for optimizing WUE and nutrient status in tomato leaves in a future freshwater-limited and higher-CO2 environment. [ABSTRACT FROM AUTHOR]

Transgenic Bt rice (abbr. Bt rice) has provided a powerful tactics to control the striped stemborer Chilo suppressalis as one key lepidopteran pest in the paddyfields of China. Globally rising carbon dioxide (i.e., CO2) concentration has been predicted to affect the Cry protein contents in plant tissues of Bt rice and thus might affect its control efficiency to target insect pests. To reveal the resistance ability and the corresponding mechanism of C. suppressalis to Bt rice during different growth stage under elevated CO2 (eCO2), we carried out this experiment to measure the Bt toxin contents in Bt rice stems grown under ambient CO2 (aCO2) (400 ppm) and eCO2 (800 ppm) at seedling, tillering and heading stages, and to observe the larval mortality and bioassay the activity of midgut protease and the expression levels of Bt-toxin-receptor genes, aminopeptidases (APNs) in C. suppressalis larvae. Compared with aCO2, eCO2 increased the Bt-toxin content of Bt rice at seedling stage (+6.66%), and decreased that at heading stages (−13.99%), and significantly reduced the Bt-toxin content at tillering stage (−15.21%). And the larval mortality of C. suppressalis was lower as reared with Bt rice stems during tillering stage grown under eCO2 in contrast to aCO2. In addition, eCO2 significantly increased the activity of total protease, tryptase-like enzyme and aminopeptidase of C. suppressalis larvae fed on Bt rice during seedling stage, and significantly reduced the activity of tryptase-like enzyme and aminopeptidase of C. suppressails larvae fed on Bt rice during tillering and heading stages respectively. Moreover, eCO2 significantly increased the expression level of APN1 and APN5 of C. suppressails larvae fed on Bt rice during seedling stage, and significantly reduced the expression level of APN5 of C. suppressalis larvae fed on Bt rice during tillering and heading stages respectively. In summary, the control efficiency of Bt rice to target insect pests under eCO2 showed a downward trend during tillering and heading stages, and especially during tillering stage. [ABSTRACT FROM AUTHOR]

Wheat interactions against fungal pathogens, such as Zymoseptoria tritici, are affected by changes in abiotic factors resulting from global climate change. This situation demands in-depth knowledge of how predicted increases in temperature and CO2 concentration ([CO2]) will affect wheat—Z. tritici interactions, especially in durum wheat, which is mainly grown in areas considered to be hotspots of climate change. Therefore, we characterized the response of one susceptible and two resistant durum wheat accessions against Z. tritici under different environments in greenhouse assays, simulating the predicted conditions of elevated temperature and [CO2] in the far future period of 2070–2099 for the wheat-growing region of Córdoba, Spain. The exposure of the wheat—Z. tritici pathosystem to elevated temperature reduced disease incidence compared with the baseline weather conditions, mainly affecting pathogen virulence, especially at the stages of host penetration and pycnidia formation and maturation. Interestingly, simultaneous exposure to elevated temperature and [CO2] slightly increased Z. tritici leaf tissue colonization compared with elevated temperature weather conditions, although this fungal growth did not occur in comparison with baseline conditions, suggesting that temperature was the main abiotic factor modulating the response of this pathosystem, in which elevated [CO2] slightly favored fungal development. [ABSTRACT FROM AUTHOR]

Growing quality seedlings is a challenge for sustainable cacao production as the survival rate of young seedlings is strongly influenced by environmental factors that affect the productivity of cacao farmers. In this study, cacao (Theobroma cacao L.) seedlings were cultivated in a nursery, and the effects of elevated CO2 concentrations (approximately 800 ppm) applied to cacao seedlings during daytime (6:00–17:59) on the root growth, morphology, and leaf photosynthetic capacity were examined. Treatment with elevated CO2 significantly improved root growth, dry matter weight, and root/shoot ratio. Three-dimensional imaging of roots showed that lateral roots grew longer horizontally, lateral roots and fine roots were distributed over a larger area, and root surface and root volume increased significantly under elevated CO2 treatment. Accurate quantification of root morphology using X-ray CT indicated that the treatment with elevated CO2 concentrations may significantly affect root quality during the seedling stage by expanding the distribution range of lateral and fine roots, which increases the ability of lateral roots to elongate and absorb water and nutrients from the superficial layers. The photosynthetic characteristics of the aboveground leaves of cacao seedlings exposed to elevated CO2 concentrations showed a tendency to adapt to elevated CO2 concentrations by increasing light-use efficiency and CO2-use efficiency. Therefore, the treatment of cacao seedlings with elevated CO2 concentrations improved the growth quality of seedlings due to the characteristics of the roots as large sinks. [ABSTRACT FROM AUTHOR]

Cytochrome P450 monooxygenase (CYP) is one of the three detoxification metabolic enzymes in insects, and is involved in the metabolism and transformation of endogenous substances as well as the activation and degradation of exogenous compounds. This study aims to reveal the molecular mechanism of CYP9E2 in Tribolium castaneum in adapting to high-CO2 stress. By predicting the sequence function of CYP9E2, analyzing the temporal and spatial expression profile of TcCYP9E2, and using RNAi to silence TcCYP9E2 combined with a high-CO2 stress treatment, we measured the carbohydrate content, trehalase activity, and gene expression levels in trehalose metabolism of T. castaneum. A bioinformatics analysis showed that the predicted molecular weight of the protein encoded by TcCYP9E2 is 60.15, the theoretical isoelectric point is 8.63, there is no signal peptide, and the protein is hydrophilic. An evolutionary tree analysis showed that TcCYP9E2 belongs to the CYP6 family and belongs to the CYP3 group; and the spatiotemporal expression profile results showed that TcCYP9E2 was highly expressed in the larvae midgut 48 h after injection of dsCYP9E2, with survival rates decreasing with the increase in CO2 concentration. Under the condition of 75% CO2, the contents of glycogen, glucose, ATP, and membrane-bound trehalase decreased significantly after the injection of dsCYP9E2. The expression of TRE-1, TRE-2, and GP in trehalose metabolism and energy pathways was significantly downregulated. [ABSTRACT FROM AUTHOR]

With the growing number of datasets to describe greenhouse gas (GHG) emissions, there is an opportunity to develop novel predictive models that require neither the expense nor time required to make direct field measurements. This study evaluates the potential for machine learning (ML) approaches to predict soil GHG emissions without the biogeochemical expertise that is required to use many current models for simulating soil GHGs. There are ample data from field measurements now publicly available to test new modeling approaches. The objective of this paper was to develop and evaluate machine learning (ML) models using field data (soil temperature, soil moisture, soil classification, crop type, fertilization type, and air temperature) available in the Greenhouse gas Reduction through Agricultural Carbon Enhancement network (GRACEnet) database to simulate soil CO2 fluxes with different fertilization methods. Four machine learning algorithms—K nearest neighbor regression (KNN), support vector regression (SVR), random forest (RF) regression, and gradient boosted (GB) regression—were used to develop the models. The GB regression model outperformed all the other models on the training dataset with R2 = 0.88, MAE = 2177.89 g C ha−1 day−1, and RMSE 4405.43 g C ha−1 day−1. However, the RF and GB regression models both performed optimally on the unseen test dataset with R2 = 0.82. Machine learning tools were useful for developing predictors based on soil classification, soil temperature and air temperature when a large database like GRACEnet is available, but these were not highly predictive variables in correlation analysis. This study demonstrates the suitability of using tree-based ML algorithms for predictive modeling of CO2 fluxes, but no biogeochemical processes can be described with such models. [ABSTRACT FROM AUTHOR]

Urban vertical farming is an innovative solution to address the increasing demand for food in densely populated cities. With advanced technology and precise monitoring, closed urban vertical farms can optimize growing conditions for plants, resulting in higher yields and improved crop quality. However, to fully optimize closed urban vertical farming systems, research is needed to enhance crop yields and reduce the growing season. The present study is focused on the research of the mutual influence of microclimate parameters, such as temperature, humidity, and carbon dioxide concentration, as well as the spectral composition of light, humidity, and amount of peat in the substrate. The research was conducted within the cultivation of the "Innovator" potato variety at the experimental automated vertical farm of the "Fundamentals of Biotechnology" of the Russian Academy of Sciences. Based on the correlation and Fourier analysis of the dependences of soil moisture and carbon dioxide concentration on time, it is shown that after watering potatoes, there is a 56 h delayed decrease in the concentration of carbon dioxide in the cultivation room, which can be explained by a delayed increase in the intensity of the photosynthesis process. Moreover, a comparison of CO2 dependence on time with the lighting dynamics at the scale of one day indicates the presence of the intrinsic daily biological rhythm of the CO2 absorption rate that does not depend on the external lighting conditions. In addition, by analyzing the dependencies of microclimate parameters and the spectral composition of the lighting over time, it was found that switching on lighting influences the microclimate parameters, which can be explained by the heating of LEDs used for lighting. Moreover, the multiple regression analysis of microclimate parameters and soil moisture showed that an increase in peat content in the substrate leads to a transition from the decisive influence of air humidity on soil moisture to the dominant influence of air temperature. The obtained results reveal the complex mutual influence of the parameters determining the growing conditions within automated closed vertical farms. Consideration of this influence is necessary when optimizing the conditions of vegetation and the development of intelligent plant-growing systems. [ABSTRACT FROM AUTHOR]

High-precision observations provide an efficient way to calculate greenhouse gas emissions from agricultural fields and their spatial and temporal distributions. Two high-resolution laser heterodyne radiometers (LHRs) were deployed in the suburb of Hefei (31.9°N 117.16°E) for the remote sensing of atmospheric CO2, CH4 and N2O above rice paddy fields. The atmospheric transmittance spectra of CO2, CH4 and N2O were measured simultaneously in real time, and the atmospheric total column abundance was retrieved from the measured data based on the optimal estimation algorithm, with errors of 0.7 ppm, 4 ppb and 2 ppb, respectively. From July to October, the abundance of CO2 in the atmospheric column that was influenced by emissions from rice fields increased by 0.7 ppm CH4 by 30 ppb, and by 4 ppb N2O. During the rice growth season, rice paddy fields play a role in carbon sequestration. CH4 and N2O emissions from paddy fields are negatively correlated. The method of baking rice paddy fields reduces CH4 emissions from rice fields, but N2O emissions from rice fields are usually subsequently increased. The measurement results showed that LHRs are highly accurate in monitoring atmospheric concentrations and have promising applications in monitoring emissions from rice paddy fields. In the observation period, rice paddy fields can sequester carbon, and CH4 and N2O emissions from rice fields are negatively correlated. The LHRs have strong application prospects for monitoring emissions from agricultural fields. [ABSTRACT FROM AUTHOR]

Persimmon cv. Giombo is astringent at harvest and must be subjected to astringency removal treatment. To date, the most widespread treatment for this variety involves applying ethanol instead of high CO2 concentrations, which is the usual treatment with other varieties. This study aims to evaluate the effect of high CO2 or ethanol concentrations as deastringency treatments on the quality and flesh structure of 'Giombo´ persimmon during cold storage. The deastringency process was faster in the fruit treated with CO2 than with ethanol. One day after treatment, the CO2-treated fruit showed lower soluble tannin levels than those detected sensorially for this variety, while with the ethanol-treated fruit, these values were obtained after 25 storage days plus the shelf-life period. The tannin insolubilisation process was observed by light microscopy. Loss of flesh firmness during storage was more pronounced when fruit were previously treated with ethanol than with CO2. This is closely related to greater parenchyma degradation during storage caused by ethanol treatment, which was observed by a microstructural study by cryo-scanning electron microscopy. Therefore, as deastringency treatment for 'Giombo', applying CO2 instead of ethanol treatment is recommended for better fruit quality, especially when fruit are to be cold-stored. [ABSTRACT FROM AUTHOR]

The effects of elevated CO2 (eCO2) levels on field-grown cucumbers have been extensively studied. However, the variations in photosynthate accumulation in summer-grown cucumbers simultaneously exposed to eCO2 and varying day-night temperatures (DNF) still remain unexplored. This study aimed to investigate the effects of DNF different CO2 conditions [ambient CO2 (aCO2; 400–600 μmol mol−1) and eCO2 (800–1000 μmol mol−1)] on dry matter production and dry matter distribution in summer-grown cucumbers under two DNF treatments (35/10 °C and 25/20 °C, day/night). We observed that long-term eCO2 exposure increased C assimilation and photosynthate accumulation in leaves, resulting in feedback inhibition of the leaf area. Under both DNF treatments, the total dry matter distribution to fruits under eCO2 conditions was approximately 15% higher than that under aCO2 conditions. Furthermore, soluble sugar content and C:N ratio increased with long-term eCO2 exposure, indicating increased C allocation, photosynthate accumulation, and distribution. However, low night temperatures (LT) inhibited respiration and increased dry matter accumulation by 30% under eCO2 conditions. Additionally, eCO2 increased fruit fresh weight by 8% and 12% under both DNF treatments compared to aCO2. This suggests that long-term eCO2 exposure and varying DNF exhibited different effects through different metabolic mechanisms on cucumber growth at high temperatures. eCO2 conditions probably increased dry matter distribution to improve fruit quality, and LT treatment altered the respiration rate to restore photosynthesis, thereby increasing photosynthate distribution to fruits. Therefore, a combination of CO2 enrichment and DNF can be used to improve fruit quality and yield at high temperatures. [ABSTRACT FROM AUTHOR]

An eddy covariance (EC) GHG study was conducted at two comparable agroecosystems in the Central region of European Russia. The study was conducted in 2013 at the RTSAU Experimental Field with Umbric Albeluvisols (Moscow) and a private farm field with Chernozems in the Pristen area (Kursk region). Both studies involved barley crops, but the fields differed in climate, soil and technological conditions. Diurnal values of net ecosystem exchange (NEE) were two times higher in Kursk than in Moscow. The higher gross primary production (GPP) in Kursk was characterized by better climate and soil conditions and, partially, by the low intensity practices of semi-organic farming. GPP dynamics of the two agroecosystems were significantly different only during the first 50 days of vegetation; however, NEE seasonal differences persisted throughout the growing period, with the trends changing until the end of barley ripening. General trends for ecosystem respiration and GPP were determined by the crop phase. NEE seasonal dynamics showed that the Chernozem agroecosystem was characterized by an almost 2-fold increase in the range of CO2 fluxes, largely determined by hydrologic regime features. Since yield in Kursk was 50% lower than that in Moscow, it may be concluded that the use of modern fertilizing and crop protection systems converts a larger portion of GPP into yield mass. [ABSTRACT FROM AUTHOR]

Supercritical fluid extraction (SFE), using CO2, is a novel, sustainable and very efficient technique for the recovery of highly apolar compounds. However, the recovery of phenolic compounds requires the use of different co-solvent combinations such as water and ethanol to enhance the recovery of these compounds through the optimization of a number of variables. In this sense, the effect of pressure (100, 150 and 200 bar), temperature (50, 65 and 80 °C), extraction time (30, 60, 90, 120, 150 and 180 min) and the effect of the different percentages of ethanol and water as co-solvents on the composition and phenolic content of moringa leaf extracts were evaluated. Six major flavonoids were identified by ultra-high-performance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer (UHPLC-Q-ToF-MS). Pressure and temperature had a significant effect on the phenolic composition of the extracts, as well as on their concentrations. The highest concentration of total flavonoids compounds (TFCs) was obtained by using a mixture of CO2 and water of 50:50 (v/v) at 100 bar, at 65 °C after a 120 min extraction time that produced a concentration of 11.66 mg ± 0.02 mg TFC g−1 sample, which corresponds to 89.0% of the total flavonoids of the sample, obtained by exhaustive extraction. [ABSTRACT FROM AUTHOR]

Predicting the growth response of seedlings from the environmental responses of photosynthesis and metabolism may be improved by considering the dynamics of non-structural carbohydrate (NSC) over a diurnal cycle. Attenuation of growth metabolism when NSC content is low could explain why some NSC is conserved through the night. A dynamic model, incorporating diurnal variation in NSC, is developed to simulate growth of seedlings hour-by-hour. I compare predictions of this model to published growth and NSC data for seedlings that varied according to temperature, light, day length, or CO2. Prolonged-darkness experiments show a temperature dependent upper limit on the respiration capacity. Respiration is attenuated as NSC is depleted. Furthermore, when NSC is high at dawn, inhibition of photosynthesis could attenuate the accumulation of NSC under low temperature, high light, or high CO2. These concepts are used to simulate plant metabolism and growth rates and diurnal variation of NSC in tomato seedlings under two light levels and various temperatures. Comparison of other results using the same model parameters show the dynamic model could predict results for starch and starch-less plants, and when growth was affected by CO2 enrichment and day length. [ABSTRACT FROM AUTHOR]

The use of nitrogenous fertilizers in agriculture can cause uncontrolled gas emissions, such as N2O and CO2, leading to global warming and serious climate change. In this study, we evaluated the greenhouse gases emissions (GHGs) that are concomitant with applied different rates of N fertilization, such as 60%, 70%, 80%, 90%, 100%, 110%, and 120% of the recommended dose in green beans grown under three irrigation systems (surface, subsurface, and drip irrigation). The obtained results showed that GHGs were positively correlated with increasing the rate of N fertilization. Meanwhile, the subsurface irrigation system followed by drip irrigation achieved the highest significant (p ≤ 0.05) values regarding the growth and pod yield attributes. Furthermore, N supplements at 90% and/or 100% of the recommended dose under the subsurface irrigation system led to the highest concentration of chlorophyll, vitamin C, total protein, and activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POX). Proline and pod fibers were decreased in parallel with increasing the N rate, while water use efficiency (WUE) was improved with increasing the rate of N supplements up to 100% or 110% of the recommended dose. [ABSTRACT FROM AUTHOR]

Agricultural soils are a major source of greenhouse gases. Biochar is a soil improver and, when applied to the soil, sequesters carbon. However, a different combination of soil and climatic conditions and biochar leads to different research results. In this research, the effects of 1 kg/m2 and 3 kg/m2 biochar application to clay soils on the CO2 flow in field experiments along two cropping seasons in the Russian Far East were investigated. Data showed that biochar significantly reduces the cumulative flow of soil CO2, compared with untreated field plots. In 2018, the greatest reduction in soil CO2 emissions (28.2%) with 3 kg/m2 of biochar was obtained, while in 2019, the greatest decrease in the cumulative CO2 flow at the application dose of 1 kg/m2 (57.7%) was recorded. A correlation between a decrease in the value of the cumulative CO2 flux and an increase in the biomass grown in the studied areas of agricultural crops during the season of 2018 was found. [ABSTRACT FROM AUTHOR]

Biochar, an ecologically friendly soil amendment, is suggested for large-scale field application for its multiple potential benefits, including carbon sequestration, crop yield improvement, and the abatement of greenhouse gas emissions. However, it is unknown how effective it is in changing soil properties and its associated yield improvement when biochar is co-applied with lime in acidic soil. Here, we examined the effects of two different biochars, i.e., rice husk biochar (RHB) and oil palm empty fruit bunches biochar (EFBB), and lime on nutrient availability, the yield of maize, and soil CO2 emission of acid soil. Biochars were applied at two different rates (10 and 15 t ha−1) in combination with two rates of lime (100% and 75%), while the recommended rate of NPK fertilizers, 100% lime, and without any amendments (control) were also included. Hybrid sweet corn was grown in pots with 20 kg soils for 75 days. Plant performance and soil analyses were performed before and after crop maize cultivation while CO2 emission was recorded. Compared to the control, combined RHB biochars with lime significantly buffered soil pH and increased nutrient availability (e.g., P by 137%), while reducing Al and Fe concentration at harvest. These changes in soil properties significantly increased maize yield (by 77.59%) and nutrient uptake compared to the control. Between the two biochars, RHB was relatively more effective in making these changes than EFBB. However, this treatment contributed to a greater carbon loss as CO2 (209% and 145% higher with RHB and EFBB) from soil than the control. We believe that biochar-mediated buffering of soil pH is responsible for this change. Our results suggest that combined biochar application could bring desirable changes in soil properties and increase crop performance, although these effects can be short-lived. [ABSTRACT FROM AUTHOR]

The increasing quantities of organic residues are becoming one of the most important problems for climate change mitigation. Sustainable utilization technologies are required to minimize the effect of recycling on the environment. Nevertheless, treated residues should be part of the circular bioeconomy. One of the most promising processes is the biogas system, with the final products biogas and digestate, which contain valuable nutrients and are therefore suitable as agricultural fertilizers. However, there is lack of research data on the effectiveness of digestate on environmental factors including soil quality as well as crop productivity and quality. In this study, we compare the roles of different digestates (chicken manure digestate, cow manure digestate, and pig manure digestate) on spring wheat productivity, soil microbial activities, and greenhouse gas emissions in loam and sandy loam soil under controlled climate conditions. The liquid digestate applied was equivalent to 170 kg N ha−1 of total N presented. Overall, results showed that the two soil types responded differently to the addition of the digestates, and the benefits depended on soil characteristics as well as on the type of the digestate applied. There was a higher effect on soil microbial activity in sandy loam soil compared to that of loam soil. Chicken manure digestate had the highest value of dehydrogenase activity and soil microbial biomass C of 9.23 µg TPFg−1 h−1 and 175.6 µg g−1 across the two soil types. CO2 and N2O emissions were moderately higher in loam soil when compared to that of sandy loam soil. The highest CO2 peak emission at 0.0107 µg ha−1 h−1 occurred in pig manure digestate in the sandy loam soil, and regular peak patterns observed in loam soil fertilized with pig digestate manure. Chicken manure digestate had the highest peak emissions across both soil types at 0.007950 mg ha−1 h−1 and 0.5667 mg ha−1 h−1 in the loam and sandy loam soil, respectively. The biomass yield varied across the soil types irrespective of the digestate applied. The agricultural benefits of digestates in different receiving soil ecosystems supplying essential nutrients for crop productivity, coupled with its environmental benefits, makes it an encouraging prospect in temperate climate zones. [ABSTRACT FROM AUTHOR]

Elevated atmospheric CO2 (eCO2) can significantly enhance plant metabolism and improve their nutritional quality. Although several studies addressed the effect of eCO2 on plants, to our knowledge, there are no studies that have applied eCO2 to improve growth, chemical composition, and biological properties of ajwain (Trachyspermum ammi) during sprouting. Herein, eCO2 (620 µmol mol−1) was employed to enhance photosynthetic reactions. Improved photosynthesis induced primary and bioactive secondary metabolism, which led to improved biological activities of T. ammi sprouts in comparison with control sprouts and seeds. eCO2-treated sprouts showed significantly (p < 0.05) higher levels of most measured nutritional primary and secondary metabolites like soluble sugars, essential amino acids, organic acids, essential oils, phenolics, and flavonoids than control sprouts, which had significantly higher values than control seeds. eCO2 significantly improved the antimicrobial properties of T. ammi sprouts against 11 out of 13 microbial species than control sprouts, which had more potent antimicrobial activities than seeds. The significant increase in the antioxidant potential of treated sprouts was indicated by improved levels of ferric reducing antioxidant power (FRAP), DPPH, and oxygen radical absorbance capacity (ORAC). In addition, the anticancer activity against four different human tumor cell lines was significantly (p < 0.05) boosted by both sprouting and eCO2 exposure. Thus, the present study confirms the synergistic effect of sprouting with eCO2 exposure as promising approaches to produce ajwain sprouts with rich nutraceuticals, effective phytochemicals, and enhanced biological activities. [ABSTRACT FROM AUTHOR]

Amaranthus retroflexus L. (Amaranthaceae), Redroot pigweed, is native to North America, but has become a weed of agriculture worldwide. Previous research into competition with food crops found it significantly reduces yields. Additionally, taxonomy, biomass allocation, physiological responses to light intensity, water stress, elevated CO2, and herbicide resistance have been investigated. To extend other research findings, we investigated growth and biomass yield in response to (i) soil moisture stress, and (ii) drought and elevated CO2. Additionally, we investigated seed germination rates following exposure to three elevated temperatures for two different time periods. Overall, moisture stress reduced plant height, stem diameter, and number of leaves. Elevated CO2 (700 ppm) appeared to reduce negative impacts of drought on biomass productivity. Heating seeds at 120 °C and above for either 180 or 300 s significantly reduced germination rate. These results inform an understanding of potential responses of A. retroflexus to future climate change and will be used to predict future occurrence of this weed. The finding that exposing seeds to high temperatures retards germination suggests fire could be used to prevent seed germination from soil seed banks, particularly in no-till situations, and therefore may be used to address infestations or prevent further spread of this weed. [ABSTRACT FROM AUTHOR]

Cacao (Theobroma cacao L.) was grown as an understory tree in agroforestry systems where it received inadequate to adequate levels of photosynthetic photon flux density (PPFD). As atmospheric carbon dioxide steadily increased, it was unclear what impact this would have on cacao growth and development at low PPFD. This research evaluated the effects of ambient and elevated levels carbon dioxide under inadequate to adequate levels of PPFD on growth, physiological and nutrient use efficiency traits of seven genetically contrasting juvenile cacao genotypes. Growth parameters (total and root dry weight, root length, stem height, leaf area, relative growth rate and net assimilation rates increased, and specific leaf area decreased significantly in response to increasing carbon dioxide and PPFD. Increasing carbon dioxide and PPFD levels significantly increased net photosynthesis and water-use efficiency traits but significantly reduced stomatal conductance and transpiration. With few exceptions, increasing carbon dioxide and PPFD reduced macro–micro nutrient concentrations but increased uptake, influx, transport and nutrient use efficiency in all cacao genotypes. Irrespective of levels of carbon dioxide and PPFD, intraspecific differences were observed for growth, physiology and nutrient use efficiency of cacao genotypes. [ABSTRACT FROM AUTHOR]

Stomata, the microscopic pores surrounded by a pair of guard cells on the surfaces of leaves and stems, play an essential role in regulating the gas exchange between a plant and the surrounding atmosphere. Stomatal development and opening are significantly influenced by environmental conditions, both in the short and long term. The rapid rate of current climate change has been affecting stomatal responses, as a new balance between photosynthesis and water-use efficiency has to be found. Understanding the mechanisms involved in stomatal regulation and adjustment provides us with new insights into the ability of stomata to process information and evolve over time. In this review, we summarize the recent advances in research on the underlying mechanisms of the interaction between environmental factors and stomatal development and opening. Specific emphasis is placed on the environmental factors including light, CO2 concentration, ambient temperature, and relative humidity, as these factors play a significant role in understanding the impact of global climate change on plant development. [ABSTRACT FROM AUTHOR]

Cover crops (CC), particularly legumes, are key to promote soil carbon (C) sequestration in no-tillage. Nevertheless, the mechanisms regulating this process need further elucidation within a broad comprehensive framework. Therefore, we investigated effects of CC quality: black oat (Avena strigosa Schreb) (oat), common vetch (Vicia sativa L.) (vetch), and oat + vetch on carbon dioxide-C (CO2-C) emission (124 days) under conventional- (CT), minimum- (MT) and no-tillage (NT) plots from a long-term experiment in Southern Brazil. Half-life time (t1/2) of CC residues and the apparent C balance (ACB) were obtained for CT and NT. We linked our data to long-term (22 years) soil C and nitrogen (N) stocks and crop yield data of our experimental field. Compared to CT, NT increased t1/2 of oat, oat + vetch and vetch by 3.9-, 3.1- and 3-fold, respectively; reduced CO2-C emissions in oat, oat + vetch and vetch by 500, 600 and 642 kg ha−1, respectively; and increased the ACB (influx) in oat + vetch (195%) and vetch (207%). For vetch, CO2-C emission in MT was 77% greater than NT. Legume CC should be preferentially combined with NT to reduce CO2-C emissions and avoid a flush of N into the soil. The legume based-NT system showed the greatest soil C and N sequestration rates, which were significantly and positively related to soybean (Glycine max (L.) Merrill) and maize (Zea mays L.) yield. Soil C (0–90 cm depth) and N (0–100 cm depth) sequestration increments of 1 kg ha−1 corresponded to soybean yield increments of 1.2 and 7.4 kg ha−1, respectively. [ABSTRACT FROM AUTHOR]

The intensification of livestock production, to accommodate rising human population, has led to a higher emission of ammonia into the environment. For the reduction of ammonia emissions, different management steps have been reported in most EU countries. Some authors, however, have criticized such individual measures, because attempts to abate the emission of ammonia may lead to significant increases in either methane, nitrous oxide, or carbon dioxide. In this study, we carried out a meta-analysis of experimental European data published in peer-reviewed journals to evaluate the impact of major agricultural management practices on ammonia emissions, including the pollution swapping effect. The result of our meta-analysis showed that for the treatment, storage, and application stages, only slurry acidification was effective for the reduction of ammonia emissions (−69%), and had no pollution swapping effect with other greenhouse gases, like nitrous oxide (−21%), methane (−86%), and carbon dioxide (−15%). All other management strategies, like biological treatment, separation strategies, different storage types, the concealing of the liquid slurry with different materials, and variable field applications were effective to varying degrees for the abatement of ammonia emission, but also resulted in the increased emission of at least one other greenhouse gas. The strategies focusing on the decrease of ammonia emissions neglected the consequences of the emissions of other greenhouse gases. We recommend a combination of treatment technologies, like acidification and soil incorporation, and/or embracing emerging technologies, such as microbial inhibitors and slow release fertilizers. [ABSTRACT FROM AUTHOR]

The agricultural sector faces looming challenges including dwindling fertiliser reserves, environmental impacts of conventional soil inputs, and increasingly difficult growing conditions wrought by climate change. Naturally-occurring rocks and minerals may help address these challenges. In this case, we explore opportunities through which the geosphere could support viable agricultural systems, primarily via a literature review supplemented by data analysis and preliminary-scale experimentation. Our objective is to focus on opportunities specifically relating to emerging agricultural challenges. Our findings reveal that a spectrum of common geological materials can assist across four key agricultural challenges: 1. Providing environmentally-sustainable fertiliser deposits especially for the two key elements in food production, nitrogen (via use of slow release N-rich clays), and phosphorus (via recovery of the biomineral struvite) as well as through development of formulations to tap into mineral nutrient reserves underlying croplands. 2. Reducing contamination from farms—using clays, zeolites, and hydroxides to intercept, and potentially recycle nutrients discharged from paddocks. 3. Embedding drought resilience into agricultural landscapes by increasing soil moisture retention (using high surface area minerals including zeolite and smectite), boosting plant availability of drought protective elements (using basalts, smectites, and zeolites), and decreasing soil surface temperature (using reflective smectites, zeolites, and pumices), and 4. mitigating emissions of all three major greenhouse gases—carbon dioxide (using fast-weathering basalts), methane (using iron oxides), and nitrous oxide (using nitrogen-sorbing clays). Drawbacks of increased geological inputs into agricultural systems include an increased mining footprint, potential increased loads of suspended sediments in high-rainfall catchments, changes to geo-ecological balances, and possible harmful health effects to practitioners extracting and land-applying the geological materials. Our review highlights potential for 'geo-agriculture' approaches to not only help meet several key emerging challenges that threaten sustainable food and fiber production, but also to contribute to achieving some of the United Nations Sustainable Development Goals—'Zero Hunger,' 'Life on Land,' and 'Climate Action.' [ABSTRACT FROM AUTHOR]

Climate change will inevitably affect agriculture. Simulations of the effects of climate change on the agronomic performance (plant height, biomass dry weight, number of spikes, grain weight, harvest index, and 1000-kernel weight) of nine durum wheat cultivars were performed to identify the genotypes that will have a greater yield potential over the next 50 years. Plants were grown in two Fitotron® CGR crop growth chambers: "room 2020" designed to reproduce the current climatic conditions (control) and "room 2070", designed to simulate the expected climate for the year 2070 in the RCP8.5 scenario (800 ppm, elevated [CO2], and a temperature increase of 2.5 °C). The plant life cycle was clearly shorter in "room 2070" due to the physiological strategy of the plant to escape the high summer temperatures through early ripening of the kernels. Again, in "room 2070", the modern cultivars Rusticano, San Carlo, and Simeto and the old cultivar Cappelli increased the grain yield. Surprisingly, Cappelli seemed to be particularly suitable for cultivation in an environment rich in atmospheric CO2 and under high temperature stress, since it produced a grain yield that was approximately three times higher than the other varieties. [ABSTRACT FROM AUTHOR]

Enhancing root-zone (RZ) dissolved inorganic carbon (DIC) levels of plants grown aeroponically can increase biomass accumulation but may also alter phytohormone profiles in planta. These experiments investigated how CO2 gas (1500 ppm) added to an aeroponic system affected phytohormone concentrations of lettuce (Lactuca sativa) and sweet pepper (Capsicum annuum) plants. Phytohormonal profiling of root and leaf tissues revealed a solitary treatment difference in lettuce plants, an increased shoot jasmonic acid (JA) concentration under elevated RZ CO2. Since JA is considered a growth inhibitor, growth promotion of lettuce under elevated RZ CO2 does not seem related to its phytohormone profile. On the other hand, pepper plants showed changes in foliar phytohormone (aminocyclopropane-1-carboxylic acid, ACC, trans-zeatin, tZ and salicylic acid, SA) concentrations, which were correlated with decreased leaf growth in some experiments. Foliar accumulation of ACC alongside decreased leaf tZ concentrations may mask a positive effect of elevated RZ CO2 on pepper growth. Diverse phytohormone responses to elevated RZ CO2 between different species may be involved in their different growth responses. [ABSTRACT FROM AUTHOR]

A combination of organic and conservation approaches have not been widely tested, neither considering agronomic implications nor the impacts on the environment. Focussing on the effect of agricultural practices on greenhouse gas (GHG) emissions from soil, the hypothesis of this research is that the organic conservation system (ORG+) may reduce emissions of N2O, CH4 and CO2 from soil, compared to an integrated farming system (INT) and an organic (ORG) system in a two-year irrigated vegetable crop rotation set up in 2014, in a Mediterranean environment. The crop rotation included: Savoy cabbage (Brassica oleracea var. sabauda L. cv. Famosa), spring lettuce (Lactuca sativa L. cv. Justine), fennel (Foeniculum vulgare Mill. cv. Montebianco) and summer lettuce (L. sativa cv. Ballerina). Fluxes from soil of N2O, CH4 and CO2 were measured from October 2014 to July 2016 with the flow-through non-steady state chamber technique using a mobile instrument equipped with high precision analysers. Both cumulative and daily N2O emissions were mainly lower in ORG+ than in INT and ORG. All the cropping systems acted as a sink of CH4, with no significant differences among treatments. The ORG and ORG+ systems accounted for higher cumulative and daily CO2 emissions than INT, maybe due to the stimulating effect on soil respiration of organic material (fertilizers/plant biomass) supplied in ORG and ORG+. Overall, the integration of conservation and organic agriculture showed a tendency for higher CO2 emissions and lower N2O emissions than the other treatments, without any clear results on its potential for mitigating GHG emissions from soil. [ABSTRACT FROM AUTHOR]