Journal Description
Nitrogen
Nitrogen
is an international, peer-reviewed, open access journal on the whole field of nitrogen research published quarterly online by MDPI.
- Open Access—free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, CAPlus / SciFinder, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.5 days after submission; acceptance to publication is undertaken in 3.2 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: APC discount vouchers, optional signed peer-review and reviewer names published annually in the journal.
Latest Articles
Effects of Seasonal Variation on Nitrogen Use in Brazilian Cerrado Grass Communities
Nitrogen 2024, 5(2), 373-385; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020024 - 24 Apr 2024
Abstract
In savanna ecosystems, the seasonal effects of nitrogen forms and availability, as well as their utilization by plants, influence the abundance and distribution of herbaceous species in grassland communities. This study examines seasonal effects on nitrogen availability and utilization by native grass species
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In savanna ecosystems, the seasonal effects of nitrogen forms and availability, as well as their utilization by plants, influence the abundance and distribution of herbaceous species in grassland communities. This study examines seasonal effects on nitrogen availability and utilization by native grass species in the Cerrado, a savanna ecosystem in Brazil. Ammonium and nitrate levels in soil, nitrate acquisition and transport, and Nitrate Reductase Activity (NRA) in different plant parts during dry and wet periods were assessed. Results indicated higher soil nitrate availability during the wet period, influenced by precipitation, with leaves showing a higher nitrate content compared to roots. There was seasonal modulation in nitrate reduction, with leaves being the primary site during the dry period and roots during the wet period. The studied grass species exhibited heterogeneous responses to seasonal nitrogen availability, potentially affecting community abundance patterns. Findings suggest that edaphoclimatic seasonality plays a crucial role in nitrogen distribution and utilization capacity by grass plants in the Cerrado, contributing to the understanding of these ecosystems’ ecology.
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(This article belongs to the Special Issue Nitrogen Signaling in Plants)
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Recent Advances in Application of 1D Nanomaterials for Photocatalytic Nitrogen Fixation
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Ragesh Nath R., Shamkumar P. Deshmukh, Sachin J. Kamble and Valmiki B. Koli
Nitrogen 2024, 5(2), 349-372; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020023 - 22 Apr 2024
Abstract
Ammonia, as the second most-produced chemical worldwide, serves diverse roles in the industrial and agricultural sectors. However, its conventional production via the Haber–Bosch process poses significant challenges, including high energy consumption and carbon dioxide emissions. In contrast, photocatalytic nitrogen (N2) fixation,
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Ammonia, as the second most-produced chemical worldwide, serves diverse roles in the industrial and agricultural sectors. However, its conventional production via the Haber–Bosch process poses significant challenges, including high energy consumption and carbon dioxide emissions. In contrast, photocatalytic nitrogen (N2) fixation, utilizing solar energy with minimal emissions, offers a promising method for sustainable ammonia synthesis. Despite ongoing efforts, photocatalytic nitrogen fixation catalysts continue to encounter challenges such as inadequate N2 adsorption, limited light absorption, and rapid photocarrier recombination. This review explores how the electronic structure and surface characteristics of one-dimensional nanomaterials could mitigate these challenges, making them promising photocatalysts for N2 fixation. The review delves into the underlying photocatalytic mechanisms of nitrogen fixation and various synthesis methods for one-dimensional nanomaterials. Additionally, it highlights the role of the high surface area of one-dimensional nanomaterials in enhancing photocatalytic performance. A comparative analysis of the photocatalytic nitrogen fixation capabilities of different one-dimensional nanomaterials is provided. Lastly, the review offers insights into potential future advancements in photocatalytic nitrogen fixation.
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(This article belongs to the Topic Carbon and Nitrogen Cycling in Agro-Ecosystems and Other Anthropogenically Maintained Ecosystems)
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Crop Rotation and Nitrogen Fertilizer on Nitrate Leaching: Insights from a Low Rainfall Study
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Isabeli P. Bruno, Augusto G. Araújo, Gustavo H. Merten, Audilei S. Ladeira and Victor M. Pinto
Nitrogen 2024, 5(2), 329-348; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020022 - 19 Apr 2024
Abstract
The intensive use of agricultural fertilizers containing nitrogen (N) can increase the risk of nitrate (NO3−) leaching. However, little information exists regarding its interaction with other factors that influence NO3− leaching, such as no-tillage, which is associated with
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The intensive use of agricultural fertilizers containing nitrogen (N) can increase the risk of nitrate (NO3−) leaching. However, little information exists regarding its interaction with other factors that influence NO3− leaching, such as no-tillage, which is associated with different crop rotation schemes. The objective of this study was to quantify the leachate NO3− concentration and load below the root zone in two different crop rotations under no-tillage, with and without mineral N fertilizer. The experiment was conducted in a no-tillage area in Brazil between 2018 and 2020. The factors were two crop rotations (diversified and simplified) and two N fertilization managements (with and without N fertilizer). The soil solution was collected with suction lysimeters (1 m depth), the NO3− concentration (mg L−1) was spectrophotometrically determined, and the NO3− load (kg ha−1) was calculated from the volume of water drained and the NO3− concentration. The results were categorized into 24 evaluation periods. NO3− leaching was extremely low due to low rainfall throughout the experiment, with no significant differences between the factors and treatments. In the presence of N fertilization, leaching was substantially greater when rainfall increased, and vice versa. No significant difference was observed between the crop rotation schemes, except for one period in which the simplified soybean rotation exhibited high leaching. The evaluated treatments showed less NO3− leaching during the four periods when grass species were cultivated, indicating the importance of grasses in rotation systems.
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(This article belongs to the Special Issue Nitrogen Management and Water-Nitrogen Interactions in Agriculture)
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Open AccessArticle
Nitrogen Cycling in Widgeongrass and Eelgrass Beds in the Lower Chesapeake Bay
by
Emily French, Ashley R. Smyth, Laura K. Reynolds and Kenneth A. Moore
Nitrogen 2024, 5(2), 315-328; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020021 - 18 Apr 2024
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Eelgrass (Zostera marina) loss occurs worldwide due to increasing water temperatures and decreasing water quality. In the U.S., widgeongrass (Ruppia maritima), a more heat-tolerant seagrass species, is replacing eelgrass in certain areas. Seagrasses enhance sediment denitrification, which helps to mitigate
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Eelgrass (Zostera marina) loss occurs worldwide due to increasing water temperatures and decreasing water quality. In the U.S., widgeongrass (Ruppia maritima), a more heat-tolerant seagrass species, is replacing eelgrass in certain areas. Seagrasses enhance sediment denitrification, which helps to mitigate excess nitrogen in coastal systems. Widgeongrass and eelgrass have different characteristics, which may affect sediment nitrogen cycling. We compared net N2 fluxes from vegetated areas (eelgrass and widgeongrass beds, using intact cores that included sediment and plants) and adjacent unvegetated areas from the York River, in the lower Chesapeake Bay during the spring and summer of one year. We found that seagrass biomass, sediment organic matter, and NH4+ fluxes were significantly higher in eelgrass beds than in widgeongrass beds. Eelgrass was also net denitrifying during both seasons, while widgeongrass was only net denitrifying in the summer. Despite differences in the spring, the seagrass beds had a similar rate of N2 production in the summer and both had higher denitrification rates than unvegetated sediments. Both species are important ecosystem components that can help to mitigate eutrophication in coastal areas. However, as the relative composition of these species continues to change, differences in sediment nitrogen cycling may affect regional denitrification capacity.
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Open AccessArticle
Whole Genome Analysis of Streptomyces spp. Strains Isolated from the Rhizosphere of Vitis vinifera L. Reveals Their Role in Nitrogen and Phosphorus Metabolism
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Gustavo Montes-Montes, Román González-Escobedo, Laila N. Muñoz-Castellanos, Graciela D. Avila-Quezada, Obed Ramírez-Sánchez, Alejandra Borrego-Loya, Ismael Ortiz-Aguirre and Zilia Y. Muñoz-Ramírez
Nitrogen 2024, 5(2), 301-314; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020020 - 16 Apr 2024
Abstract
The rhizospheric microorganisms of agricultural crops play a crucial role in plant growth and nutrient cycling. In this study, we isolated two Streptomyces strains, Streptomyces sp. LM32 and Streptomyces sp. LM65, from the rhizosphere of Vitis vinifera L. We then conducted genomic analysis
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The rhizospheric microorganisms of agricultural crops play a crucial role in plant growth and nutrient cycling. In this study, we isolated two Streptomyces strains, Streptomyces sp. LM32 and Streptomyces sp. LM65, from the rhizosphere of Vitis vinifera L. We then conducted genomic analysis by assembling, annotating, and inferring phylogenomic information from the whole genome sequences. Streptomyces sp. strain LM32 had a genome size of 8.1 Mb and a GC content of 72.14%, while Streptomyces sp. strain LM65 had a genome size of 7.3 Mb and a GC content of 71%. Through ANI results, as well as phylogenomic, pan-, and core-genome analysis, we found that strain LM32 was closely related to the species S. coelicoflavus, while strain LM65 was closely related to the species S. achromogenes subsp. achromogenes. We annotated the functional categories of genes encoded in both strains, which revealed genes involved in nitrogen and phosphorus metabolism. This suggests that these strains have the potential to enhance nutrient availability in the soil, promoting agricultural sustainability. Additionally, we identified gene clusters associated with nitrate and nitrite ammonification, nitrosative stress, allantoin utilization, ammonia assimilation, denitrifying reductase gene clusters, high-affinity phosphate transporter and control of PHO regulon, polyphosphate, and phosphate metabolism. These findings highlight the ecological roles of these strains in sustainable agriculture, particularly in grapevine and other agricultural crop systems.
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(This article belongs to the Special Issue Nitrogen Cycling and Bacterial Community)
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Open AccessArticle
Empirical Correlation between Electrical Conductivity and Nitrogen Content in Biochar as Influenced by Pyrolysis Temperature
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Everton Geraldo de Morais, Carlos Alberto Silva, Suduan Gao, Leônidas Carrijo Azevedo Melo, Bruno Cocco Lago, Jéssica Cristina Teodoro and Luiz Roberto Guimarães Guilherme
Nitrogen 2024, 5(2), 288-300; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020019 - 09 Apr 2024
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Much progress has been made in understanding the conditions of biochar production related to biochar properties and carbon (C). Still, very little knowledge has been gained regarding the effects on nitrogen (N), one of the most critical nutrients affected by pyrolysis temperature (PT).
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Much progress has been made in understanding the conditions of biochar production related to biochar properties and carbon (C). Still, very little knowledge has been gained regarding the effects on nitrogen (N), one of the most critical nutrients affected by pyrolysis temperature (PT). Analysis of N in biochar is costly, and alternative methods should be developed to estimate the N content in biochar quickly under different pyrolysis conditions. We hypothesized that there was a correlation between biochar N content and its electrical conductivity (EC). We aimed to evaluate total N and the effect of PT through the correlation with EC, a parameter that can be easily measured. Biochar products derived from coffee husk (CH) and chicken manure (CM) produced at increasing PT (300 to 750 °C) were used for the study and measured for total N and EC. The increase in PT caused significant N loss, consequently reducing total N content in biochars, with the highest loss (82%) and lowest total N content (1.2 g kg−1) found in CM biochar pyrolyzed at 750 °C. The lowest N loss (21% for CH biochar and 36% for CM biochar) was observed at a PT of 300 °C. A negative correlation between EC and total N and a positive correlation with N loss were found in both biochar products across the wide range of PT investigated. To preserve the N content in biochars, the PT should not exceed 400 °C. Our results indicate that EC is a fast and accurate biochar proxy attribute capable of predicting the N content and its loss in coffee husk and chicken manure-derived biochars as the pyrolysis temperature increased from 300 °C to 750 °C and could be used as an alternative to predict the N in biochar easily. A more extensive set of biochar samples and pyrolysis conditions should be tested to validate this approach.
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Open AccessArticle
Assessing the Impact of Nitrogen Fertilization, Variety Selection, Year and Their Interaction on Wheat Yield and Yield Components
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Oussama Hnizil, Aziz Baidani, Ilham Khlila, Nasserelhaq Nsarellah and Ali Amamou
Nitrogen 2024, 5(2), 266-287; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020018 - 09 Apr 2024
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This five-year study (2016–2021) in Morocco’s Mediterranean climate investigated the effect of nitrogen fertilization and genotypic selection on wheat yield and associated components. Utilizing a split-plot design, the study assessed five wheat genotypes—’Faraj’, ‘Luiza’, ‘Itri’, ‘Karim’ and ‘Nassira’—under three nitrogen application rates (120,
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This five-year study (2016–2021) in Morocco’s Mediterranean climate investigated the effect of nitrogen fertilization and genotypic selection on wheat yield and associated components. Utilizing a split-plot design, the study assessed five wheat genotypes—’Faraj’, ‘Luiza’, ‘Itri’, ‘Karim’ and ‘Nassira’—under three nitrogen application rates (120, 60 and 0 kg/ha) across thirty plots with two replicates. Interactions between nitrogen and year showed marked significance in yield (p = 0.001), biomass (p = 0.002), TKW (p = 0.003) and Spk/m2 (p = 0.001), underscoring the variability in optimal nitrogen application rates across different years. Additionally, significant interactions between variety and year were observed for biomass (p = 0.001) and G/m2 (p = 0.001), indicating variability in the performance of different varieties across years. The ‘Itri’ genotype showed the highest yield in 2017, while ‘Luiza’ was pre-eminent in 2018, with ‘Itri’ producing the most biomass. ‘Faraj’ demonstrated consistent superiority in yield and biomass during 2019 and 2020. Our integrated principal component analysis and quadratic models elucidated that an intermediate nitrogen rate of 60 kg/ha (N2) was particularly advantageous for the ‘Faraj’ and ‘Karim’ genotypes. These findings highlight the substantial impact of informed nitrogen level adjustment and genotypic selection on yield optimization.
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Open AccessArticle
N Losses from an Andisol via Gaseous N2O and N2 Emissions Increase with Increasing Ruminant Urinary–N Deposition Rate
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Magdalena A. Ramírez-Sandoval, Nadine Loick, Dante E. Pinochet, Maria López-Aizpun, M. Jordana Rivero and Laura M. Cárdenas
Nitrogen 2024, 5(2), 254-265; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5020017 - 22 Mar 2024
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Agricultural soils account for about 60% of the global atmospheric emissions of the potent greenhouse gas nitrous oxide (N2O). One of the main processes producing N2O is denitrification, which occurs under oxygen-limiting conditions when carbon is readily available. On
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Agricultural soils account for about 60% of the global atmospheric emissions of the potent greenhouse gas nitrous oxide (N2O). One of the main processes producing N2O is denitrification, which occurs under oxygen-limiting conditions when carbon is readily available. On grazed pastures, urine patches create ideal conditions for denitrification, especially in soils with high organic matter content, like Andisols. This lab study looks at the effects of Urine-urea-N load on the Andisol potential to emit N2O. For this, we investigated the effects of three levels of urea-N concentrations in cow urine on emissions of N2O, N2, and CO2 under controlled conditions optimised for denitrification to occur. Results show total N2O emissions increased with increasing urine-N concentration and indicate that denitrification was the main N2O-producing process during the first 2–3 days after urine application, though it was most likely soil native N rather than urine-N being utilised at this stage. An increase in soil nitrate indicates that a second peak of N2O emissions was most likely due to the nitrification of ammonium hydrolysed from the added urine, showing that nitrification and denitrification have the potential to play a big part in N losses and greenhouse gas production from these soils.
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Open AccessArticle
Sustainability Analysis of Nitrogen Use Efficiency in Soybean-Corn Succession Crops of Midwest Brazil
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Francisco Gilberto Erthal Risi, Cristina Moll Hüther, Ciro Abbud Righi, Renan Caldas Umburanas, Tiago Tezotto, Durval Dourado Neto, Klaus Reichardt and Carlos Rodrigues Pereira
Nitrogen 2024, 5(1), 232-253; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010016 - 12 Mar 2024
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Nitrogen (N) is abundant in the atmosphere as N2, which is converted into reactive forms (Nr) for plant assimilation. In pre-industrial times, atmospheric N2 conversion to Nr balanced Nr reconversion to N2, but 20th-century human activity intensified this conversion
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Nitrogen (N) is abundant in the atmosphere as N2, which is converted into reactive forms (Nr) for plant assimilation. In pre-industrial times, atmospheric N2 conversion to Nr balanced Nr reconversion to N2, but 20th-century human activity intensified this conversion via synthetic fertilizers, biological N2 fixation, and fossil fuel burning. The surplus of Nr detrimentally impacts ecosystems and human well-being. This study aimed to assess the N use efficiency in the soil–plant system of the soybean-corn succession ( ) in Mato Grosso and Mato Grosso do Sul, Brazil’s midwest. We estimated N macrofluxes in and identified key agro-environmental indicators. Between 2008 and 2020, the yearly sowed area for the increased by 3.3-fold (currently 7.3 million ha). The average annual input of net anthropogenic Nr, average annual N balance, and N loss in was estimated to be ~204 kg [N] ha−1, 57 kg [N] ha−1, and 30 kg [N] ha−1, respectively, indicating persistent N accumulation and loss. The average results of the agronomic efficiency and N retention indicator in the was 0.71 and 0.90, respectively. Modest N use efficiency results reflect N loss effects. Despite these limitations, there are opportunities in for management strategies to reduce N loss and enhance efficiency.
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Open AccessArticle
Can Foliar-Applied Omeprazole Improve the Yield, Assimilation, Recovery and Nitrogen Use Efficiency in Bean Plants?
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Carlos Abel Ramírez-Estrada, Esteban Sánchez, María Antonia Flores-Córdova, Celia Chávez-Mendoza, Sandra Pérez-Álvarez and Rosa María Yáñez-Muñoz
Nitrogen 2024, 5(1), 219-231; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010015 - 12 Mar 2024
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The low efficiency of nitrogen (N) fertilizers is a frequent problem in agriculture that impacts the environment. Omeprazole (OMP) has been reported to promote N uptake and assimilation in tomato, basil, and corn. However, information about the effect of omeprazole on N assimilation,
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The low efficiency of nitrogen (N) fertilizers is a frequent problem in agriculture that impacts the environment. Omeprazole (OMP) has been reported to promote N uptake and assimilation in tomato, basil, and corn. However, information about the effect of omeprazole on N assimilation, recovery, and N use efficiency parameters for bean plants is limited. Therefore, the objective of the present study was to determine the effect of foliar applications of OMP at 0, 1, 10, and 100 µM on nitrogen assimilation, growth, yield, nitrogen use efficiency parameters, and recovery percentage in green bean plants. Green bean plants cv. Strike grown in pots were used. Biomass, yield, nitrate reductase activity, photosynthetic pigments concentration, soluble amino acids and protein concentrations, total nitrogen concentration, nitrogen use efficiency parameters, and nitrogen recovery were analyzed. The results obtained indicate that the application of OMP at 1 µM increased yield and biomass, promoted N assimilation through higher NR enzyme activity, higher amino acid concentration, higher N use efficiency coefficient, and allowed a more efficient nitrogen recovery percentage.
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Open AccessArticle
Do the Leaves of Multiple Invasive Plants Decompose More Easily than a Native Plant’s under Nitrogen Deposition with Different Forms?
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Chuang Li, Yue Li, Shanshan Zhong, Zhelun Xu, Zhongyi Xu, Mawei Zhu, Yuqing Wei, Congyan Wang and Daolin Du
Nitrogen 2024, 5(1), 202-218; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010014 - 04 Mar 2024
Cited by 1
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This study aimed to clarify the differences in the decomposition rates, soil carbon and nitrogen contents, soil enzyme activities, and the structure of the soil bacterial community between the four Asteraceae invasive plants (AIPs), Bidens pilosa L., Conyza canadensis (L.) Cronq., Solidago canadensis
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This study aimed to clarify the differences in the decomposition rates, soil carbon and nitrogen contents, soil enzyme activities, and the structure of the soil bacterial community between the four Asteraceae invasive plants (AIPs), Bidens pilosa L., Conyza canadensis (L.) Cronq., Solidago canadensis L., and Symphyotrichum subulatum (Michx.) G.L. Nesom, and the native plant Pterocypsela laciniata (Houtt.) Shih under the artificially modeled nitrogen with four forms (including nitrate, ammonium, urea, and the mixed nitrogen forms with an equal mixture of three individual nitrogen forms). The mixed nitrogen forms significantly increased the decomposition rate of the four AIPs and P. laciniata. The positive effects of the mixed nitrogen forms on the decomposition rate of the four AIPs and P. laciniata were obviously greater than those of individual nitrogen forms. Nitrogen with four forms visibly up- or down-regulated the dominant role of predominant soil bacterial biomarkers, and significantly increased the species number, richness, and phylogenetic diversity of the soil bacterial community, as well as the number of most of the functional gene pathways of the soil bacterial communities involved in the decomposition process. The decomposition rate of the four AIPs was similar to that of P. laciniata. The leaves of C. canadensis decomposed more easily than those of S. subulatum. The decomposition process of the four AIPs caused remarkable changes in the relative abundance of several taxa of the soil bacterial community and soil bacterial beta diversity, and caused apparent up- or down-regulation in the dominant role of predominant soil bacterial biomarkers and the number of several functional gene pathways of the soil bacterial communities involved in the decomposition process.
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Open AccessArticle
Cytokinin Biosynthesis Is Affected by Selenium and Nitrate Availabilities to Regulate Shoot and Root Growth in Rice Seedlings
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Lubia S. Teixeira, Thiago A. L. Mota, Deisy J. C. Lopez, Victor A. Amorim, Carla S. Almeida, Genaina A. Souza and Dimas M. Ribeiro
Nitrogen 2024, 5(1), 191-201; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010013 - 04 Mar 2024
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Selenium (Se) and nitrate have the potential to modify rice root architecture, but it is unclear how Se is linked to changes in the rice seedlings nitrate status. Thus, rice seedlings were grown in nutrient solutions containing either 0- or 10-µM Se that
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Selenium (Se) and nitrate have the potential to modify rice root architecture, but it is unclear how Se is linked to changes in the rice seedlings nitrate status. Thus, rice seedlings were grown in nutrient solutions containing either 0- or 10-µM Se that were supplemented with 0.05 (low nitrate condition) or 5.0 mM nitrate (high nitrate condition). Se application to seedlings treated with low nitrate led to sugar accumulation in shoot and root and increased cytokinin concentrations in root, while decreasing cytokinin concentrations in shoot compared with seedlings in 0.05 mM nitrate alone. This, in turn, resulted in decreased shoot growth, while downregulation of OsXTH and OsEXP negatively affected root expansion. On the other hand, Se combined with 5.0 mM nitrate did not affect sugar concentration in tissues compared with seedlings in 5.0 mM nitrate. Moreover, Se negatively regulated the cytokinin biosynthesis in shoot and root of seedlings grown under 5.0 mM nitrate. The reduction in cytokinin concentrations by Se under high nitrate condition decreased shoot growth, but increased root growth through induction of OsXTH and OsEXP. Thus, many of the effects of Se in shoot and root growth are due to a shift in nitrate status of the seedlings.
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Open AccessArticle
Incident Light Level Influences Elemental Budgets of Serianthes nelsonii Merr. Leaf Development
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Thomas E. Marler
Nitrogen 2024, 5(1), 177-190; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010012 - 01 Mar 2024
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Recovery efforts for the endangered Serianthes nelsonii have been deficient. To learn more about leaf development costs, the content of biomass and essential elements were determined in the supportive and laminae tissue of leaves that were constructed under different levels of incident light.
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Recovery efforts for the endangered Serianthes nelsonii have been deficient. To learn more about leaf development costs, the content of biomass and essential elements were determined in the supportive and laminae tissue of leaves that were constructed under different levels of incident light. The biomass required to construct a leaf in 22% light transmission was 65% of that in full sun, and light treatment did not influence the balance between supportive and laminae tissues. Concentrations of carbon, phosphorus, iron, manganese, and boron were greatest for in full-sun laminae, but those of nitrogen, potassium, calcium, magnesium, and zinc were greatest in shaded laminae. The same patterns with regard to light were exhibited in supportive tissues for carbon, nitrogen, potassium, calcium, magnesium, and zinc. In contrast, the supportive tissue phosphorus content was greatest in shaded leaves, and the light level did not influence the supportive tissue concentrations of the remaining elements. The leaf laminae consistently exhibited greater concentrations of elements with the exception of potassium and nickel, which were greater in the supportive tissues. These results indicate that the construction of full-sun S. nelsonii leaves is more costly than that of shaded leaves, and the transfer of biomass and essential elements between the supportive and laminae tissues is not substantially influenced by the developmental light level. Identifying the drivers of S. nelsonii leaf element concentrations is crucial for understanding the role of this charismatic tree in community-level processes.
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Open AccessArticle
Enhancing Sustainability in Potato Crop Production: Mitigating Greenhouse Gas Emissions and Nitrate Accumulation in Potato Tubers through Optimized Nitrogen Fertilization
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Camila Seno Nascimento, Carolina Seno Nascimento, Breno de Jesus Pereira, Paulo Henrique Soares Silva, Mara Cristina Pessôa da Cruz and Arthur Bernardes Cecílio Filho
Nitrogen 2024, 5(1), 163-176; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010011 - 25 Feb 2024
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The complex ramifications of global climate change, which is caused by heightened concentrations of greenhouse gases in the Earth’s atmosphere, are deeply concerning. Addressing this crisis necessitates the immediate implementation of adaptive mitigation strategies, especially within the agricultural sector. In this context, this
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The complex ramifications of global climate change, which is caused by heightened concentrations of greenhouse gases in the Earth’s atmosphere, are deeply concerning. Addressing this crisis necessitates the immediate implementation of adaptive mitigation strategies, especially within the agricultural sector. In this context, this study aimed to assess how the supply of nitrogen (N) (0, 70, 140, and 210 kg N ha−1) in the forms of ammonium nitrate and urea affects the agronomic performance, food quality, greenhouse gas emissions (GHG), and carbon footprint of potato plants. The examined hypothesis was that by precisely calibrating N doses alongside appropriate sourcing, over-fertilization in potato cultivation can be mitigated. A decline in stomatal conductance and net photosynthetic rate disturbs physiological mechanisms, reflecting in biomass production. Application of 136 kg N ha−1 as urea showed a remarkable yield increase compared to other doses and sources. The highest nitrate content in potato tubers was achieved at 210 kg N ha−1 for both sources, not exceeding the limit (200 mg kg−1 of fresh mass) recommended for human consumption. The lowest carbon footprint was obtained when 70 kg N ha−1 was applied, around 41% and 26% lower than when 210 kg N ha−1 and 140 kg N ha−1 were applied, respectively. The results demonstrated that over-fertilization not only worsened the yield and tuber quality of potato plants, but also increased greenhouse gas emissions. This information is valuable for establishing an effective fertilization program for the potato crop and reducing carbon footprint.
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Open AccessArticle
The Evaluation of a Novel Denitrifying Woodchip Bioreactor: Fairmont, MN, USA
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Limeimei Xu, Kerry Holmberg and Joe Magner
Nitrogen 2024, 5(1), 152-162; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010010 - 21 Feb 2024
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The risk of nitrate contamination became a reality for Fairmont in Minnesota, when water rich in NO3-N exceeded the drinking water standard of 10 mg/L. This was unexpected because this city draws its municipal water from a chain of lakes that
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The risk of nitrate contamination became a reality for Fairmont in Minnesota, when water rich in NO3-N exceeded the drinking water standard of 10 mg/L. This was unexpected because this city draws its municipal water from a chain of lakes that are fed primarily by shallow groundwater under row-crop land use. Spring soil thaw drives cold water into a subsurface pipe where almost no NO3-N reduction occurs. This paper focuses on NO3-N reduction before the water enters the lakes and no other nitrogen management practices in the watershed. A novel denitrifying bioreactor was constructed behind a sediment forebay, which then flowed into a chamber covered by a greenhouse before entering a woodchip bioreactor. In 2022 and 2023, water depth, dissolved oxygen, and temperature were measured at several locations in the bioreactor, and continuous NO3-N was measured at the entry and exit of the bioreactor. The results showed better performance at a low water depth with lower dissolved oxygen and higher water temperature. The greenhouse raised the inlet temperature in 2022 but did not in 2023. The forebay and the greenhouse may have impeded the denitrification process due to the high dissolved oxygen concentrations in the influent and the stratification of dissolved oxygen caused by algae in the bioreactor.
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Open AccessCommunication
Uncovering the Unusual Long Chains of Vegetative Cells within Single Colonies of the Dryland Nitrogen-Fixing Cyanobacterium Nostoc flagelliforme
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Xiang Gao, Chang Liu and Wensheng Liang
Nitrogen 2024, 5(1), 144-151; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010009 - 20 Feb 2024
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Heterocyst-forming cyanobacteria that colonize the drylands contribute to carbon and nitrogen supplies in nutrient-poor soils. As one of the representative cyanobacteria, Nostoc flagelliforme adapts well to the arid environment in the form of filamentous colonies (or filaments). To date, the adaptive changes, either genetic
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Heterocyst-forming cyanobacteria that colonize the drylands contribute to carbon and nitrogen supplies in nutrient-poor soils. As one of the representative cyanobacteria, Nostoc flagelliforme adapts well to the arid environment in the form of filamentous colonies (or filaments). To date, the adaptive changes, either genetic or micromorphological, that occur within single colonies of dryland cyanobacteria remain largely unclear. In this study, unusual long chains or trichomes of vegetative cells (not containing heterocysts) were observed within N. flagelliforme filaments. And the overall heterocyst frequency in the trichomes was counted to be 1.3–2.7%, different from the usually observed 5–10% heterocyst frequency in model Nostoc strains when grown in nitrogen-deprived medium. Thus, these phenomena seem contradictory to our usual recognition of Nostoc strains. Related transcriptional and heterocyst frequency analyses suggested no genetically significant alteration in heterocyst formation and nitrogen fixation in this strain. Also, the amounts of nitrogen sources in the extracellular polysaccharide (EPS) matrix released by N. flagelliforme cells that may cause the low heterocyst frequency were assessed to be equivalent to 0.28–1.10 mM NaNO3. When combining these findings with the habitat characters, it can be envisaged that the released nitrogen sources from cells are confined, accumulated, and re-utilized in the EPS matrix, thereby leading to the formation of reduced heterocyst frequency and long-chained vegetative cells. This study will contribute to our understanding of the distinctive adaptation properties of colonial cyanobacteria in dryland areas.
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Open AccessReview
Optimizing the Nitrogen Use Efficiency in Vegetable Crops
by
Hector Valenzuela
Nitrogen 2024, 5(1), 106-143; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010008 - 05 Feb 2024
Cited by 2
Abstract
Nitrogen (N) is the most limiting nutrient for the production of vegetable crops, but anthropogenic sources pose risks due to its transformation into several reactive forms and movement throughout the environment. The bulk of the N research to date to improve Nitrogen Use
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Nitrogen (N) is the most limiting nutrient for the production of vegetable crops, but anthropogenic sources pose risks due to its transformation into several reactive forms and movement throughout the environment. The bulk of the N research to date to improve Nitrogen Use Efficiency (NUE) has followed a reductionist factorial approach focused on synthetic N application rates and crop growth response, under monocultures. The increased adoption of diversified cropping systems, organic N sources, and alternative management practices makes it more challenging to unravel N form transformation, movement, and crop uptake dynamics, in time and space. Here, based on a selected review of the recent literature, we propose a holistic approach of nutrient management to highlight key management and production variables as well as multilevel cropping system, genetic, environmental, ecological, and socioeconomic interactions to improve the N cycle and NUE. The best management strategies to improve NUE include both organic and inorganic N rate calibration studies, germplasm selection, crop rotations, identification of nutrient x nutrient interactions, and pest and water management. Agroecological practices that may improve NUE include vegetational diversification in time and space, integrated crop–livestock systems, conservation tillage, organic amendment inputs, legume-based cropping systems, as well as a landscape approach to nutrient management.
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Open AccessArticle
Organic Nitrogen Forms in Soils Treated with Cattle Manure
by
Cassia Rita Adame, Roberta Souto Carlos, Lucas Boscov Braos, Manoel Evaristo Ferreira and Mara Cristina Pessôa da Cruz
Nitrogen 2024, 5(1), 91-105; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010007 - 01 Feb 2024
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The availability of nitrogen in the soil is influenced by several factors associated with the forms and characteristics of organic nitrogen present in it, as well as by any property that impacts its microbiological and biochemical activity. The objective of the present work
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The availability of nitrogen in the soil is influenced by several factors associated with the forms and characteristics of organic nitrogen present in it, as well as by any property that impacts its microbiological and biochemical activity. The objective of the present work was to evaluate the combined effect of manure fertilization, soil type, and incubation time on soil N forms and availability. The experiment was conducted in a factorial scheme (2 soils × with (20 Mg ha−1) or without manure × 4 incubation times (15, 45, 90, and 180 days)). The levels of organic matter and fractions of organic N and mineral N were evaluated. Fertilization increased the organic matter and mineral N content in both soils, but the effect of fertilization on the organic N fractions was different depending on the type of soil. In the clayey soil, there was an accumulation of nitrogen in the unidentified hydrolysable fraction, whereas, in the sandy soil, the greatest increase occurred in the hydrolysable ammonium fraction. The application of manure generated different effects on the dynamics of N forms, depending on the type of soil. It is important to understand the impacts of different soil properties on the forms of nitrogen.
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Open AccessArticle
Effectiveness of Rhizobium tropici sp. Strain UD5 Peat Biofertilizer Inoculant on Growth, Yield, and Nitrogen Concentration of Common Bean
by
Auges Gatabazi, Ashwell Rungano Ndhlala, Mireille Asanzi Mvondo-She and Semakaleng Mpai
Nitrogen 2024, 5(1), 79-90; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010006 - 01 Feb 2024
Abstract
Common bean (Phaseolus vulgaris L.) ranks among the most produced and consumed legume crops and contains essential macro- and micronutrients. Grain yield of the food crop is markedly decreased by poor management, especially a lack of additional essential nutrient elements through the
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Common bean (Phaseolus vulgaris L.) ranks among the most produced and consumed legume crops and contains essential macro- and micronutrients. Grain yield of the food crop is markedly decreased by poor management, especially a lack of additional essential nutrient elements through the application of fertilizers. In addition to the application of fertilizers, scholarly research and crop farmers have shown that the use of biofertilizer inoculants improves the yield of legume crops. The objective of this research study was to assess the effectiveness of peat-based Rhizobium tropici sp. UD5 on the growth, yield, and nitrogen concentration of common bean. The peat inoculant contained 6.5 × 109 viable cells/g. The experiment was conducted in two climatic zones, as described by the Koppen–Gieger climatic classification system. Treatments involved the peat-based inoculant Rhizobium tropici (T0 = 0 g without inoculation, T1 = 250 g of peat inoculant of strain UD5 for 50 kg seeds, T2 = 500 g of inoculant of strain UD5, and T3 = 200 g of comparative peat inoculant). The results indicated that common-bean-inoculated formulation of R. tropici sp. strain UD5 increased the following parameters compared to the controls: plant height (T1 = 18.22%, T2 = 20.41%, and T3 = 19.93% for bioclimatic zone 1; T1 = 16.78%, T2 = 20.71%, and T3 = 19.93% for bioclimatic zone 2), root length (T1 = 13.26%, T2 = 21.28%, and T3 = 19.38% for zone 1; T1 = 15.06%, T2 = 23.70%, and T3 = 19.20% for zone 2), number of nodules (T1 = 1162.57%, T2 = 1166.36%, and T3 = 1180.30% for zone 1; T1 = 1575%, T2 = 1616.5%, and T3 = 1608.25% for zone 2), size of nodules (T1 = 224.07%, T2 = 224.07%, and T3 = 208.33% for zone 1; T1 = 166.4%, T2 = 180%, and T3 = 140% for zone 2), and yield (T1 = 40.49%, T2 = 47.10%, and T3 = 45.45% for zone 1; T1 = 62.16%, T2 = 54.05%, and T3 = 58.55% for zone 2). R. tropici sp. UD5 peat inoculant formulation also increased the nitrogen concentration in leaves compared to the control (T1 = 3.75%, T2 = 1.12%, and T3 = 8.72%) in both bioclimatic zones. The findings of this study provide significant information on the positive effect of R. tropic UD5 strain peat inoculant application in the improvement of plant growth, development, and yield through the formation of nodules.
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(This article belongs to the Special Issue Microbial Nitrogen Cycling)
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Open AccessArticle
Importance of Overlooked Crop Biomass Components in Sugarcane Nitrogen Nutrition Studies
by
Daniel M.N. Poultney, Laurent Thuriès and Antoine Versini
Nitrogen 2024, 5(1), 62-78; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen5010005 - 26 Jan 2024
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Sugarcane crops typically have a high fertiliser nitrogen (N) input, with low N recovery efficiencies. Nitrogen is essential to crop productivity, but excess application can have negative environmental consequences. Despite the importance of coordinating N fertiliser input with crop N requirements, certain components
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Sugarcane crops typically have a high fertiliser nitrogen (N) input, with low N recovery efficiencies. Nitrogen is essential to crop productivity, but excess application can have negative environmental consequences. Despite the importance of coordinating N fertiliser input with crop N requirements, certain components of the sugarcane plant are typically not considered when evaluating N nutrition. The objective of this study was to establish which sugarcane crop components should be included in these evaluations given their impact on N mass accumulation and on fertiliser N recovery efficiencies. The respective biomass, N mass, and fertiliser N recovery efficiency were evaluated for sugarcane shoots, tillers, strawfall, root, and stool components over two experimental years, for fertilised (urea) and unfertilised treatments. The root component comprised, respectively, 57–65% of the aboveground N mass of fertilised sugarcane, and 74–104% of the unfertilised sugarcane. The sugarcane N requirements and uptake were shown to be more progressive over the growth-cycle when considering the strawfall and tiller components. This study emphasises the importance of evaluating belowground biomass in sugarcane N studies, and suggests that the tiller and strawfall components should also be considered when evaluating the evolution of N mass and fertiliser N recovery efficiency.
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