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 19.3 days after submission; acceptance to publication is undertaken in 4.7 days (median values for papers published in this journal in the first half of 2024).
- Journal Rank: CiteScore - Q2 (Agricultural and Biological Sciences (miscellaneous))
- Recognition of Reviewers: APC discount vouchers, optional signed peer-review and reviewer names published annually in the journal.
Impact Factor:
1.6 (2023);
5-Year Impact Factor:
1.6 (2023)
Latest Articles
Impact of Nodulation Efficiency and Concentrations of Soluble Sugars and Ureides on Soybean Water Deficit During Vegetative Growth
Nitrogen 2024, 5(4), 992-1000; https://doi.org/10.3390/nitrogen5040063 - 17 Oct 2024
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Drought is the primary limiting factor affecting soybean productivity, and is exacerbated by climate change. In legumes like soybeans, biological nitrogen fixation (BNF) is the main form of nitrogen acquisition, with nitrogen being converted into ureides. A greenhouse experiment was conducted using the
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Drought is the primary limiting factor affecting soybean productivity, and is exacerbated by climate change. In legumes like soybeans, biological nitrogen fixation (BNF) is the main form of nitrogen acquisition, with nitrogen being converted into ureides. A greenhouse experiment was conducted using the soybean cultivar BMX Zeus IPRO, with two water treatments applied during the vegetative phase: control (C) and water deficit (D). The relative water content and number of nodules were reduced in the D plants. Ureide concentrations (allantoin and allantoic acid) were higher in nodules under D conditions. However, no differences were observed in allantoin, total ureide, and soluble sugar concentrations in leaves. Our results suggest that reducing the number of nodules may be a key strategy for maintaining BNF under drought conditions and that ureide accumulation could be the primary metabolic response in this soybean cultivar. These findings indicate that the effects of water restriction on BNF are likely associated with local metabolic responses rather than a systemic ureide feedback mechanism inhibiting BNF.
Full article
Open AccessArticle
Role of Nitrogen Fertilization and Sowing Date in Productivity and Climate Change Adaptation Forecast in Rice–Wheat Cropping System
by
Khalid Hussain, Erdoğan Eşref Hakki, Ayesha Ilyas, Sait Gezgin and Muhammad Asif Kamran
Nitrogen 2024, 5(4), 977-991; https://doi.org/10.3390/nitrogen5040062 - 16 Oct 2024
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Global food security is at risk due to climate change. Soil fertility loss is among the impacts of climate change which reduces the productivity of rice–wheat cropping systems. This study investigated the effects of varying nitrogen levels and transplanting/sowing dates on the grain
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Global food security is at risk due to climate change. Soil fertility loss is among the impacts of climate change which reduces the productivity of rice–wheat cropping systems. This study investigated the effects of varying nitrogen levels and transplanting/sowing dates on the grain yield (GY) and biological yield (BY) of rice and wheat cultivars over two growing seasons (2017–2019). Additionally, the impact of climate change on the productivity of both crops was tested under a 1.5 °C temperature increase and 510 ppm CO2 concentration while nitrogen fertilization and sowing window adjustments were evaluated as adaptation options using the DSSAT and APSIM models. Results indicated that the application of 120 kg N ha−1 significantly enhanced both GY and BY in all rice cultivars. The highest wheat yields were obtained with 140 kg N ha−1 for all cultivars. Rice transplanting on the 1st of July and wheat sowing on the 15th of November showed the best yields. The statistical indices of the model’s forecast results were satisfactory for rice (R2 = 0.83–0.85, root mean square error (RMSE) = 341–441, model efficiency (EF) = 0.82–0.89) and wheat (R2 = 0.84–0.89, RMSE = 213–303, EF = 0.88–0.91). Both models predicted yield loss in wheat (20–25%) and rice (28–30%) under a climate change scenario. The models also predicted that increased nitrogen application and earlier planting would be necessary to reduce the impacts of climate change on the productivity of both crops.
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Open AccessArticle
Co-Inoculation of Soybean Seeds with Azospirillum and/or Rhizophagus Mitigates the Deleterious Effects of Waterlogging in Plants under Enhanced CO2 Concentrations
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Eduardo Pereira Shimoia, Douglas Antônio Posso, Cristiane Jovelina da-Silva, Adriano Udich Bester, Nathalia Dalla Corte Bernardi, Ivan Ricardo Carvalho, Ana Cláudia Barneche de Oliveira, Luis Antonio de Avila and Luciano do Amarante
Nitrogen 2024, 5(4), 941-976; https://doi.org/10.3390/nitrogen5040061 - 15 Oct 2024
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Rising CO2 levels, as predicted by global climate models, are altering environmental factors such as the water cycle, leading to soil waterlogging and reduced oxygen availability for plant roots. These conditions result in decreased energy production, increased fermentative metabolism, impaired nutrient uptake,
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Rising CO2 levels, as predicted by global climate models, are altering environmental factors such as the water cycle, leading to soil waterlogging and reduced oxygen availability for plant roots. These conditions result in decreased energy production, increased fermentative metabolism, impaired nutrient uptake, reduced nitrogen fixation, and altered leaf gas exchanges, ultimately reducing crop productivity. Co-inoculation techniques involving multiple plant growth-promoting bacteria or arbuscular mycorrhizal fungi have shown promise in enhancing plant resilience to stress by improving nutrient uptake, biomass production, and nitrogen fixation. This study aimed to investigate carbon and nitrogen metabolism adaptations in soybean plants co-inoculated with Bradyrhizobium elkanii, Azospirillum brasilense, and Rhizophagus intraradices under waterlogged conditions in CO2-enriched environments. Plants were grown in pots in open-top chambers at ambient CO2 concentration (a[CO2]) and elevated CO2 concentration (e[CO2]). After reaching the V5 growth stage, the plants were subjected to waterlogging for seven days, followed by a four-day reoxygenation period. The results showed that plants’ co-inoculation under e[CO2] mitigated the adverse effects of waterlogging. Notably, plants inoculated solely with B. elkanii under e[CO2] displayed results similar to co-inoculated plants under a[CO2], suggesting that co-inoculation effectively mitigates the waterlogging stress, with plant physiological traits comparable to those observed under elevated CO2 conditions.
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Open AccessReview
Advances in the Study of NO3− Immobilization by Microbes in Agricultural Soils
by
Xingling Wang and Ling Song
Nitrogen 2024, 5(4), 927-940; https://doi.org/10.3390/nitrogen5040060 - 11 Oct 2024
Abstract
The extensive application of nitrogen (N) fertilizers in agriculture has resulted in a considerable accumulation of N in the soil, particularly nitrate (NO3−), which can be easily lost to the surrounding environments through leaching and denitrification. Improving the immobilization of
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The extensive application of nitrogen (N) fertilizers in agriculture has resulted in a considerable accumulation of N in the soil, particularly nitrate (NO3−), which can be easily lost to the surrounding environments through leaching and denitrification. Improving the immobilization of NO3− by soil microorganisms in agriculture is crucial to improve soil N retention capacity and reduce the risk of NO3− loss. In this paper, we reviewed the significance of microbial immobilization of soil NO3− in soil N retention, the techniques to quantify soil gross microbial NO3− immobilization rate, and its influencing factors. Specifically, we discussed the respective contribution of fungi and bacteria in soil NO3− retention, and we clarified that the incorporation of organic materials is of vital importance in enhancing soil microbial NO3− immobilization capacities in agricultural soils. However, there is still a lack of research on the utilization of NO3− by microorganisms of different functional groups in soil due to the limited techniques. In the future, attention should be paid to how to regulate the microbial NO3− immobilization to make soil NO3− supply capacity match better with the crop N demand, thereby improving N use efficiency and reducing NO3− losses.
Full article
(This article belongs to the Special Issue Microbial Nitrogen Cycling)
Open AccessArticle
Contrasting Life-Form Influences Guam Ficus Foliar Nutrient Dynamics
by
Thomas E. Marler
Nitrogen 2024, 5(4), 915-926; https://doi.org/10.3390/nitrogen5040059 - 11 Oct 2024
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Tropical trees that remain evergreen and exhibit leaf litterfall that is gradual over time coexist with trees that are seasonally deciduous and exhibit pulsed litterfall. The manner in which these trees acquire, store, and contribute nutrients to the biogeochemical cycle may differ. Green
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Tropical trees that remain evergreen and exhibit leaf litterfall that is gradual over time coexist with trees that are seasonally deciduous and exhibit pulsed litterfall. The manner in which these trees acquire, store, and contribute nutrients to the biogeochemical cycle may differ. Green and senesced leaves from deciduous Ficus prolixa trees were compared with those from Ficus tinctoria on the island of Guam. The results enabled stoichiometry and resorption calculations. F. prolixa’s young green leaf nitrogen (N) and potassium (K) concentrations were double, and the phosphorus (P) concentration was triple, those of F. tinctoria. Concentrations converged as the leaves aged such that no differences in concentration occurred for senesced leaves, indicating that nutrient resorption proficiency did not differ between the two species. In contrast, the resorption efficiency was greater for F. prolixa than F. tinctoria for all three nutrients. The N:P values of 6–11 and K:P values of 5–7 were greater for young F. tinctoria leaves than young F. prolixa leaves. The N:K values were 1.1–1.6 and did not differ between the two species. No differences in pairwise stoichiometry occurred for senesced leaves for any of the nutrients. These Guam results conformed to global trends indicating that seasonally deciduous plants are more acquisitive and exhibit greater nutrient resorption efficiency. The differences in how these two native trees influence the community food web and nutrient cycling lies mostly in the volume and synchronicity of pulsed F. prolixa litter inputs, and not in differences in litter quality. These novel findings inform strategic foresight about sustaining ecosystem health in Guam’s heavily threatened forests.
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Open AccessArticle
Removal of Nitrogen, Phosphates, and Chemical Oxygen Demand from Community Wastewater by Using Treatment Wetlands Planted with Ornamental Plants in Different Mineral Filter Media
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José Luis Marín-Muñiz, Gonzalo Ortega-Pineda, Irma Zitácuaro-Contreras, Monserrat Vidal-Álvarez, Karina E. Martínez-Aguilar, Luis M. Álvarez-Hernández and Sergio Zamora-Castro
Nitrogen 2024, 5(4), 903-914; https://doi.org/10.3390/nitrogen5040058 - 5 Oct 2024
Abstract
This study aimed to explore the impact of various ornamental plants (Heliconia psittacorum, Etlingera elatior, Spatyphilum walisii) grown in different filter media (porous river rock (PR) and tepezyl (TZ)) on the removal of pollutants in vertical-subsurface-microcosm treatment wetlands (TWs).
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This study aimed to explore the impact of various ornamental plants (Heliconia psittacorum, Etlingera elatior, Spatyphilum walisii) grown in different filter media (porous river rock (PR) and tepezyl (TZ)) on the removal of pollutants in vertical-subsurface-microcosm treatment wetlands (TWs). This study also sought to assess the adaptability of these plant species to TW conditions. Twenty-four microcosm systems were utilized, with twelve containing PR and twelve containing TZ as the filter media. Each porous media type had three units planted with each species, and three were left unplanted. Rural community wastewater was treated in the TWs. The results showed no significant differences in the effects of the porous media on pollutant removal performance (p > 0.05). However, it was noted that while both porous media were efficient, TZ, a residue of construction materials, is recommended for sites facing economic constraints. Additionally, the removal efficiency was found to be independent of the type of ornamental plant used (p > 0.05); however, the measured parameters varied with plant spp. The adaptation of the plants varied depending on the species. H. psittacorum grew faster and produced a larger number of flowers compared to the other species (20–22 cm). S. wallisii typically produced 7–8 flowers. E. elatior did not produce flowers, and some plants showed signs of slight disease and pests, with the leaves turning yellow. In terms of plant biomass, the type of porous media used did not have a significant effect on the production of above (p = 0.111) or below-ground biomass (p = 0.092). The removal percentages for COD in the presence and absence of plants were in the ranges of 64–77% and 27–27.7%, respectively. For TN, the numbers were 52–65% and 30–31.8%, and for N-NO3, they were 54–60% and 12–18%. N-NH4 saw removal rates of 67–71% and 28–33%, while P-PO4 saw removal rates of 60–72% and 22–25%. The difference in removal percentages between microcosms with and without plants ranged from 30 to 50%, underscoring the importance of plants in the bio-removal processes (phytoremediation). These results reveal that incorporating ornamental plants in TWs with TZ for wastewater in rural areas holds great promise for enhancing the visual appeal of these systems and ultimately gaining public approval. Our findings also enable us to offer recommendations for selecting suitable plants and substrates, as well as designing combinations for TWs.
Full article
(This article belongs to the Special Issue Soil Nitrogen Cycling—a Keystone in Ecological Sustainability)
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Open AccessArticle
Iodine-Enriched Urea Reduces Volatilization and Improves Nitrogen Uptake in Maize Plants
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João Victor da Costa Cezar, Everton Geraldo de Morais, Jucelino de Sousa Lima, Pedro Antônio Namorato Benevenute and Luiz Roberto Guimarães Guilherme
Nitrogen 2024, 5(4), 891-902; https://doi.org/10.3390/nitrogen5040057 - 2 Oct 2024
Abstract
Urea is the primary source of nitrogen (N) used in agriculture. However, it has a high N loss potential through volatilization. Various mechanisms can be employed to reduce N volatilization losses by inhibiting urease. When added to urea, iodine (I) has high potential
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Urea is the primary source of nitrogen (N) used in agriculture. However, it has a high N loss potential through volatilization. Various mechanisms can be employed to reduce N volatilization losses by inhibiting urease. When added to urea, iodine (I) has high potential for this purpose. Thus, this study aimed to determine whether adding I to urea reduces volatilization losses and increases N uptake in maize plants. Maize plants were cultivated in greenhouse conditions for 36 days. Urea treatments were applied at 15 days of testing, including iodine-enriched urea, conventional urea, and no urea application. Additionally, a study concerning N volatilization from urea was conducted using the same treatments under the same environmental conditions. Iodine was incorporated and adhered to urea, at an I concentration of 0.2%, using potassium iodate (KIO3). Under controlled conditions and over a short period of time, it was observed that the application of iodine-enriched urea increased the chlorophyll b content, root N accumulation, and total N accumulation in maize plants compared with conventional urea. Moreover, iodine-enriched urea reduced N losses from volatilization by 11% compared with conventional urea. The reduction in N volatilization correlated positively with the increased chlorophyll b, total chlorophyll, root N accumulation, and total N accumulation favored by the iodine-enriched urea treatment. Our findings demonstrated that adding I to urea is an efficient and promising strategy to reduce N losses and increase N uptake in plants.
Full article
(This article belongs to the Special Issue Alternatives to Mineral Nitrogen Fertilizers in Agriculture: State of the Art, Challenges and Future Prospects)
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Open AccessArticle
A Mixture of Summer Legume and Nonlegume Cover Crops Enhances Winter Wheat Yield, Nitrogen Uptake, and Nitrogen Balance
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Jun Wang, Upendra M. Sainju and Shaohong Zhang
Nitrogen 2024, 5(4), 871-890; https://doi.org/10.3390/nitrogen5040056 - 2 Oct 2024
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Cover crops protecting soil erosion during the summer fallow in the monsoon weather may enhance dryland winter wheat yield and N relations. We examined the effects of four summer cover crops (soybean (Glycine max L., SB), sudangrass (Sorghum sudanense {Piper} Stapf,
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Cover crops protecting soil erosion during the summer fallow in the monsoon weather may enhance dryland winter wheat yield and N relations. We examined the effects of four summer cover crops (soybean (Glycine max L., SB), sudangrass (Sorghum sudanense {Piper} Stapf, SG), soybean and sudangrass mixture (SS), and no cover crop (CK)) and three N fertilization rates (0, 60, and 120 kg N ha−1) on winter wheat yield, quality, and N relations from 2017–2018 to 2020–2021 in the Loess Plateau of China. Cover crop biomass and N accumulation, soil mineral N, and winter wheat yield, protein concentration, and N uptake were greater for SB and SS than other cover crops at most N fertilization rates and years. The N fertilization rate had variable effects on these parameters. Winter wheat aboveground biomass and grain N productivities were greater for CK than other cover crops at all N fertilization rates and years. Nitrogen balance was greater for SS than other cover crops at 60 and 120 kg N ha−1 in all years. The SS with 120 kg N ha−1 can enhance soil mineral N, winter wheat yield and quality, and N balance compared to CK and SG with or without N fertilization rates.
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Open AccessArticle
Morpho-Physiological and Biochemical Responses in Prosopis laevigata Seedlings to Varied Nitrogen Sources
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Erickson Basave-Villalobos, Luis Manuel Valenzuela-Núñez, José Leonardo García-Rodríguez, Homero Sarmiento-López, José Luis García-Pérez, Celi Gloria Calixto-Valencia and José A. Sigala
Nitrogen 2024, 5(4), 857-870; https://doi.org/10.3390/nitrogen5040055 - 28 Sep 2024
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Nitrogen (N) fertilization promotes morphofunctional attributes that enhance plant performance under stress conditions, but the amount and form supplied modify the magnitude of plant responses. We assessed several morpho-physiological and biochemical responses of Prosopis laevigata seedlings to a high supply of N, provided
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Nitrogen (N) fertilization promotes morphofunctional attributes that enhance plant performance under stress conditions, but the amount and form supplied modify the magnitude of plant responses. We assessed several morpho-physiological and biochemical responses of Prosopis laevigata seedlings to a high supply of N, provided as either inorganic (NH4NO3) or organic (amino acids). Such N treatments were applied on four-month-old seedlings as a supplement of 90 mg N to a regular supply of 274 mg N plant−1. Nitrogen supply modified biomass allocation patterns between leaves and roots regardless of N form. Increased N input decreased photosynthetic capacity, even when plants had high internal N reserves. Organic N fertilization reduced the N use efficiency, but increased leaf and root amino acid concentrations. Proteins accumulated in stems in plants receiving inorganic N, while the organic N increased leaf proteins. High N supply promoted root starch accumulation irrespective of N form. Nitrogen supply did not directly influence plants’ regrowth capacity. Still, resprouting was correlated to initial root-to-shoot ratios and root starch, confirming the importance of roots as storage reserves of starch for recovering biomass after browsing. These findings have practical implications for designing nutritional management strategies in nurseries to improve seedling performance in afforestation efforts.
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Open AccessReview
Site-Specific Nitrogen Fertilizer Management Using Canopy Reflectance Sensors, Chlorophyll Meters and Leaf Color Charts: A Review
by
Ali M. Ali, Haytham M. Salem and Bijay-Singh
Nitrogen 2024, 5(4), 828-856; https://doi.org/10.3390/nitrogen5040054 - 27 Sep 2024
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The efficient management of nitrogen (N) on a site-specific basis is critical for the improvement of crop yield and the reduction of environmental impacts. This review examines the application of three primary technologies—canopy reflectance sensors, chlorophyll meters, and leaf color charts—in the context
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The efficient management of nitrogen (N) on a site-specific basis is critical for the improvement of crop yield and the reduction of environmental impacts. This review examines the application of three primary technologies—canopy reflectance sensors, chlorophyll meters, and leaf color charts—in the context of site-specific N fertilizer management. It delves into the development and effectiveness of these tools in assessing and managing crop N status. Reflectance sensors, which measure the reflection of light at specific wavelengths, provide valuable data on plant N stress and variability. The advent of innovative sensor technology, exemplified by the GreenSeeker, Crop Circle sensors, and Yara N-Sensor, has facilitated real-time monitoring and precise adjustments in fertilizer N application. Chlorophyll meters, including the SPAD meter and the atLeaf meter, quantify chlorophyll content and thereby estimate leaf N levels. This indirect yet effective method of managing N fertilization is based on the principle that the concentration of chlorophyll in leaves is proportional to the N content. These meters have become an indispensable component of precision agriculture due to their accuracy and ease of use. Leaf color charts, while less sophisticated, offer a cost-effective and straightforward approach to visual N assessment, particularly in developing regions. This review synthesizes research on the implementation of these technologies, emphasizing their benefits, constraints, and practical implications. Additionally, it explores integration strategies for combining these tools to enhance N use efficiency and sustainability in agriculture. The review culminates with recommendations for future research and development to further refine the precision and efficacy of N management practices.
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Open AccessArticle
Nitrate Removal by Floating Treatment Wetlands under Aerated and Unaerated Conditions: Field and Laboratory Results
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Jenna McCoy, Matt Chaffee, Aaron Mittelstet, Tiffany Messer and Steve Comfort
Nitrogen 2024, 5(4), 808-827; https://doi.org/10.3390/nitrogen5040053 - 25 Sep 2024
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Urban and storm water retention ponds eventually become eutrophic after years of receiving runoff water. In 2020, a novel biological and chemical treatment was initiated to remove accumulated nutrients from an urban retention pond that had severe algae and weed growth. Our approach
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Urban and storm water retention ponds eventually become eutrophic after years of receiving runoff water. In 2020, a novel biological and chemical treatment was initiated to remove accumulated nutrients from an urban retention pond that had severe algae and weed growth. Our approach installed two 6.1 m × 6.1 m floating treatment wetlands (FTWs) and two airlift pumps that contained slow-release lanthanum composites, which facilitated phosphate precipitation. Four years of treatment (2020–2023) resulted in median nitrate-N concentrations decreasing from 23 µg L−1 in 2020 to 1.3 µg L−1 in 2023, while PO4-P decreased from 42 µg L−1 to 19 µg L−1. The removal of N and P from the water column coincided with less algae, weeds, and pond muck (sediment), and greater dissolved oxygen (DO) concentrations and water clarity. To quantify the sustainability of this bio-chemical approach, we focused on quantifying nitrate removal rates beneath FTWs. By enclosing quarter sections (3.05 × 3.05 m) of the field-scale FTWs inside vinyl pool liners, nitrate removal rates were measured by spiking nitrate into the enclosed root zone. The first field experiment showed that DO concentrations inside the pool liners were well below the ambient values of the pond (<0.5 mg/L) and nitrate was quickly removed. The second field experiment quantified nitrate loss under a greater range of DO values (<0.5–7 mg/L) by including aeration as a treatment. Nitrate removal beneath FTWs was roughly one-third less when aerated versus unaerated. Extrapolating experimental removal rates to two full-sized FTWs installed in the pond, we estimate between 0.64 to 3.73 kg of nitrate-N could be removed over a growing season (May–September). Complementary laboratory mesocosm experiments using similar treatments to field experiments also exhibited varying nitrate removal rates that were dependent on DO concentrations. Using an average annual removal rate of 1.8 kg nitrate-N, we estimate the two full-size FTWs could counter 14 to 56% of the annual incoming nitrate load from the contributing watershed.
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Open AccessArticle
Plantago Species Show Germination Improvement as a Function of Nitrate and Temperature
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António Teixeira, Pietro P. M. Iannetta and Peter E. Toorop
Nitrogen 2024, 5(3), 790-807; https://doi.org/10.3390/nitrogen5030052 - 20 Sep 2024
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At the optimum temperature, which is the ideal range in which seeds germinate most efficiently, seed germination may be lower than expected under favorable conditions, and this is indicative of seed dormancy. Also, germination may be enhanced by additional and interacting factors, such
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At the optimum temperature, which is the ideal range in which seeds germinate most efficiently, seed germination may be lower than expected under favorable conditions, and this is indicative of seed dormancy. Also, germination may be enhanced by additional and interacting factors, such as nitrate and light. However, little is known about the interplay between temperature, nitrate, and seed germination. Using seeds from 22 accessions of four Plantago species that occupy distinct pedoclimates, we applied a factorial experimental design to assess the relationship between exogenously applied nitrate (KNO3) and temperature on germination in a Petri dish experiment. The data explore the relationship between seed germination, temperatures, and seed- and maternal-source soil N content as either nitrite (NO2−), nitrate (NO3−), or ammonium (NH4+). The interpretation also considered the total N and C contents of seeds, and the soil of the maternal plant (of the test seed) sources. Significant interspecific effects of nitrate and temperature on seed germination were observed. The capacity of nitrate to enhance final germination may be diminished substantially at supra-optimum temperatures, e.g., P. lagopus germination at 15 °C was 7% lower than that seen for water-only treatment. In contrast, at sub-optimum and alternating temperatures, nitrate enhanced final germination differentially across the species tested. This suggests a shift to enhanced germination at lower temperatures in the presence of sufficient soil nitrate, facilitating seedling establishment earlier in the growing season. The seeds of some Plantago species showed increased germination as a function of nitrate and temperature, particularly those of P. lagopus. The findings indicate that species (and genotype) responses correlated with the prevailing temperature and rainfall patterns of the locality; such local adaptation would ensure that seed germination and establishment occur during a period when environmental conditions are optimal.
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Open AccessArticle
Litter Decomposition Rates of Four Species of Agroecological Importance in the Peruvian Coast and Andean Highland
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Tomás Samaniego, Jorge Ramirez and Richard Solórzano
Nitrogen 2024, 5(3), 772-789; https://doi.org/10.3390/nitrogen5030051 - 13 Sep 2024
Abstract
Crop residue decomposition is fundamental for ecosystems, influencing carbon cycling, organic matter accumulation, and promoting plant development through nutrient release. Therefore, this study aimed to ascertain the rate of decomposition of four commonly cultivated crops (alfalfa, maize, avocado, and eucalyptus) along the northern
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Crop residue decomposition is fundamental for ecosystems, influencing carbon cycling, organic matter accumulation, and promoting plant development through nutrient release. Therefore, this study aimed to ascertain the rate of decomposition of four commonly cultivated crops (alfalfa, maize, avocado, and eucalyptus) along the northern coast of Lima (Huaral) and in the Ancash Mountain range (Jangas) areas. Decomposition rates were assessed using mass loss from decomposition bags measuring 15 × 10 cm, filled with 10–15 g of material tailored to each species, and buried at a depth of approximately 5 cm. Sampling occurred every three months over a year, totaling four sampling events with three replicates each, resulting in ninety-six experimental units. The findings demonstrate that the decomposition rates and the release of nutrients were markedly greater in Huaral for maize and avocado. In contrast, these rates were notably elevated in Jangas for alfalfa and eucalyptus. The leaf litter of avocado and eucalyptus (tree) had periods of accumulation and release of heavy metals such as Cd. The initial C/N ratio was one of the main factors related to the nutrient decomposition rate; in contrast, there were no significant relationships with soil properties at the study sites.
Full article
(This article belongs to the Topic Carbon and Nitrogen Cycling in Agro-Ecosystems and Other Anthropogenically Maintained Ecosystems)
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Open AccessArticle
Effects of Soil Sucrose Application on Biological Nitrogen Fixation and Aboveground Biomass Production in Leguminous Cover Crops
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Verónica Berriel
Nitrogen 2024, 5(3), 763-771; https://doi.org/10.3390/nitrogen5030050 - 6 Sep 2024
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The use of cover crops (CCs) based on tropical legumes, including Crotalaria ochroleuca, Crotalaria juncea, Crotalaria spectabilis, and Cajanus cajan, represents a pivotal aspect of agricultural rotations. These crops facilitate the incorporation of nitrogen through biological nitrogen fixation (BNF),
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The use of cover crops (CCs) based on tropical legumes, including Crotalaria ochroleuca, Crotalaria juncea, Crotalaria spectabilis, and Cajanus cajan, represents a pivotal aspect of agricultural rotations. These crops facilitate the incorporation of nitrogen through biological nitrogen fixation (BNF), thereby reducing the necessity for synthetic nitrogen fertilizers. Nevertheless, the capacity for the BNF of these species in Uruguay is relatively modest. To address this limitation, an approach is proposed that involves the immobilization of nitrogen in the soil using a highly energetic material, such as sucrose. The objective of this study was to examine the impact of incorporating sucrose into typical Uruguayan soil on aboveground dry matter production, nitrogen accumulation, and nitrogen fixation by legumes utilized as CCs. The experiments involved the planting of C. ochroleuca, C. juncea, C. spectabilis, and C. cajan in pots containing either soil alone or soil mixed with sucrose and the subsequent maintenance of these in a plant growth chamber for a period of 90 days. The addition of sucrose had a positive impact, with nearly double the aboveground dry matter production and nitrogen content observed. The percentage of nitrogen derived from the atmosphere (%Ndfa) increased significantly in all species, rising from an average of 83% to 96% in the sucrose-amended soil compared to the control. In the case of C. juncea, there was a notable threefold increase in aboveground dry matter and nitrogen accumulation across different treatments, accompanied by a 26% rise in %Ndfa and a fourfold increase in nitrogen fixation amounts. These findings indicate that C. juncea has the potential to significantly enhance performance and ecosystem services in typical Uruguayan soil.
Full article
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Open AccessArticle
Nitrogen Dynamics from Conventional Organic Manures as Influenced by Different Temperature Regimes in Subtropical Conditions
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Abu Taher Mohammad Anwarul Islam Mondol, Md. Akhter Hossain Chowdhury, Sharif Ahmed and Md Khairul Alam
Nitrogen 2024, 5(3), 746-762; https://doi.org/10.3390/nitrogen5030049 - 23 Aug 2024
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Determining nutrient-release patterns of organic manures can give an estimate of the potential amount of nutrients that a given material can contribute to crops along with chemical fertiliser. Nutrients released from organic manure depend on several factors, and temperature is one of them.
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Determining nutrient-release patterns of organic manures can give an estimate of the potential amount of nutrients that a given material can contribute to crops along with chemical fertiliser. Nutrients released from organic manure depend on several factors, and temperature is one of them. To evaluate how different types of conventional organic manures release nitrogen (N) under varying temperature conditions, an incubation study was conducted at the Bangladesh Agricultural Research Institute. Six organic manures—poultry manure (PM), vermicompost (VC), bio-slurry (BS), cowdung (CD), water-hyacinth compost (WHC), and rice straw compost (RSC)—were evaluated at three temperature regimes (15, 25, and 35 °C) to study the dynamics of N incubated for 330 days. The N release was significantly influenced by the interaction of organic manures and temperature regimes. Poultry manure-treated soil incubated at 35 °C had the highest mineralisation of all parameters than other manures. The mineralisation of N followed the order: PM > VC > BS > CD > WHC > RSC > control and 35 °C > 25 °C > 15 °C. Across different temperatures, the mineralisation rate of PM was 15–55% higher than that of other manures. At 35 °C, the mineralisation rate was 10% and 20% higher compared to 25 °C and 15 °C, respectively. The first-order kinetic models predicted the organic N release from manures satisfactorily. The findings of the present study enrich the understanding of N-release patterns under different temperature regimes that prevail in different crop growing seasons in Indo-Gangetic Plains, providing valuable data for researchers and policymakers interested in sustainable integrated nutrient management practices.
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Open AccessReview
Balance of Nitrate and Ammonium in Tropical Soil Conditions: Soil Factors Analyzed by Machine Learning
by
Risely Ferraz-Almeida
Nitrogen 2024, 5(3), 732-745; https://doi.org/10.3390/nitrogen5030048 - 19 Aug 2024
Abstract
The nitrogen/N dynamic is complex and affected by soil management (i.e., residue accumulation and correction/fertilization). In soil, most of the N is combined with organic matter (organic forms), but the N forms absorbed by plants are ammonium/NH4+ and nitrate/NO3−
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The nitrogen/N dynamic is complex and affected by soil management (i.e., residue accumulation and correction/fertilization). In soil, most of the N is combined with organic matter (organic forms), but the N forms absorbed by plants are ammonium/NH4+ and nitrate/NO3− (inorganic forms). The N recommendation for agriculture crops does not observe the N available in the soil (organic or inorganic), indicating a low efficiency in nitrogen management in soil. Based on the hypothesis that the stocks of NO3− and NH4 can be used as indicative of N status in soil but with high variation according to soil factors (soil uses and management), the objective of the study was to (i) analyze the balance of nitrate and ammonium in tropical soil with different uses and management and (ii) use machine learning to explain the nitrogen dynamic in soil and the balance of nitrate and ammonium. The results showed that soil N stocks and pH promoted the formation of three clusters with the similarity between Cluster 1 (clay texture) and Cluster 2 (loam texture), represented by higher contents of nitrate as a result of high nitrification rate and lower contents of ammonium in soil. Cluster 3 (sand texture) was isolated with different N dynamics in the soil. In agricultural soils, the content of NO3− tends to be higher than the content of NH4+. There is a high nitrification rate in clay soil explained by higher organic matter and clay content that promotes soil biology. Based on the results of machine learning, for clay and loam soil, the contents of NO3 can be used as indicative of N status as a final result of nitrification rate and higher variation in soil. However, in sandy soil, NO3 can not be used as indicative of N status due to N losses by leaching.
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(This article belongs to the Special Issue Soil Nitrogen Cycling—a Keystone in Ecological Sustainability)
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Open AccessArticle
Comparison of Organic and Inorganic Fertilization in Fenugreek Cultivation Using Nitrogen Indicators
by
Antigolena Folina, Antonios Mavroeidis, Panteleimon Stavropoulos, Lydia Eisenbach, Ioanna Kakabouki and Dimitrios Bilalis
Nitrogen 2024, 5(3), 712-731; https://doi.org/10.3390/nitrogen5030047 - 13 Aug 2024
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Nitrogen indices could be used to evaluate organic and inorganic fertilization because they provide quantitative measures of nitrogen availability in the soil, allowing for a more accurate assessment of nutrient-management practices and optimization of crop yields. This study investigates the impact of different
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Nitrogen indices could be used to evaluate organic and inorganic fertilization because they provide quantitative measures of nitrogen availability in the soil, allowing for a more accurate assessment of nutrient-management practices and optimization of crop yields. This study investigates the impact of different fertilization types and salinity on various soil parameters in fenugreek (Trigonella foenum-graecum L.) cultivation and nitrogen indices. A field experiment was established at the Agricultural University of Athens during the cropping period of 2018–2019 (CP I), 2019–2020 (CP II), and 2020–2021 (CP III) in a split-plot design with two main salinity treatments (high salinity, HS, and conventional salinity, CS) and five fertilization treatments (biocyclic–vegan humus soil (BHS), manure (FYM), compost (COMP), inorganic fertilization (11–15–15), and the control (C). The Nitrogen Balance Intensity (NBI) was statistically significantly affected by the factors of fertilization (p ≤ 0.01) and salinity (p ≤ 0.001) for CP I. The maximum NUEcrop value was recorded in the FYM treatment (0.83 ± 0.04) and the minimum in the COMP treatment (0.64 ± 0.04). Physiological efficiency (PE) was not significantly affected by any treatment for CP III. The fertilization factor significantly affected the NUEsoil index (p ≤ 0.001) for all three CPs. For CP I, the highest Nitrogen Uptake Efficiency (NUpE) value was recorded in the BHS treatment (27.08 ± 7.31) and the lowest in the C treatment (13.22 ± 7.31). There were no significant differences in CP I and CP II NUEbalance values among the NPK, BHS, and FYM treatments. These findings underscore the potential of organic fertilizers in addressing the global nitrogen challenge and promoting environmentally sustainable farming practices.
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Open AccessArticle
Effect of Time of Nitrogen Fertilization on Use of Root Reserves in Megathyrsus maximus Cultivars
by
Aline M. Motta, Luiz J. M. Motta, Lucas G. Mota, Lucas M. B. Assis, Anna B. O. Moura, Luis C. O. Borges, Gustavo B. A. Silva, Camila F. D. Duarte, Carla H. A. Cabral and Carlos E. A. Cabral
Nitrogen 2024, 5(3), 702-711; https://doi.org/10.3390/nitrogen5030046 - 10 Aug 2024
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Nitrogen is a very important nutrient in grass maintenance fertilization and therefore must be applied at the appropriate moment. The objective of this study was to identify the most responsive moment to nitrogen fertilization and to verify if root mass and the content
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Nitrogen is a very important nutrient in grass maintenance fertilization and therefore must be applied at the appropriate moment. The objective of this study was to identify the most responsive moment to nitrogen fertilization and to verify if root mass and the content of carbohydrates and nitrogen in roots influence the moment of fertilization in cultivars of Megathyrsus maximus (syn. Panicum maximum). This study was carried out simultaneously in a greenhouse using a completely randomized design, with sixteen treatments and five replications, in a 4×4 factorial design. The treatments consisted of four intervals between cultivar defoliation and nitrogen fertilization (0, 3, 6 and 9 days) and four Megathyrsus maximus cultivars, Mombasa, BRS Zuri, BRS Quenia and BRS Tamani, which were evaluated in five regrowth cycles. No difference in forage mass was observed among cultivars when fertilization was performed on days zero, three and nine after harvesting. On day nine, Mombasa showed a higher forage mass compared to BRS Tamani. Nitrogen content in the roots of Zuri decreased when fertilization was performed on the third day after defoliation, remaining constant in the other fertilization intervals. A linear reduction in root starch in BRS Zuri was observed, while in Mombasa cultivars, a linear increase was observed when fertilization was performed nine days after harvesting. Thus, nitrogen fertilization of BRS Tamani should be carried out closer to defoliation, while Mombasa, BRS Zuri and BRS Quenia can be fertilized up to nine days after harvesting, which results in greater flexibility regarding the moment of nitrogen fertilization.
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Open AccessReview
Climate Change and Nitrogen Dynamics: Challenges and Strategies for a Sustainable Future
by
Aline Viancelli and William Michelon
Nitrogen 2024, 5(3), 688-701; https://doi.org/10.3390/nitrogen5030045 - 8 Aug 2024
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Global warming driven by climate change has profound impacts on nitrogen dynamics in terrestrial and aquatic ecosystems. The increased emissions of greenhouse gases alter the distribution and availability of nitrogen, which is a critical nutrient for all living organisms. This review examines the
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Global warming driven by climate change has profound impacts on nitrogen dynamics in terrestrial and aquatic ecosystems. The increased emissions of greenhouse gases alter the distribution and availability of nitrogen, which is a critical nutrient for all living organisms. This review examines the connections between climate change and nitrogen cycling, highlighting the adverse effects on ecosystem health and productivity. The proliferation of nitrogen pollution due to agricultural runoff, industrial effluents, and urban wastewater aggravates eutrophication, leading to significant environmental and economic consequences. The imbalance in nitrogen availability not only affects plant growth and soil fertility but also disrupts aquatic ecosystems, resulting in harmful algal blooms and hypoxic conditions. Effective mitigation and adaptation strategies are essential to addressing these challenges. Sustainable agricultural practices, such as precision farming and the use of slow-release fertilizers, along with robust policies and innovative technologies, like biochar application and nitrification inhibitors, are essential in managing nitrogen levels. This review underscores the importance of interdisciplinary approaches that involve integrating insights from ecology, agronomy, and the social sciences to develop comprehensive solutions. Future research should focus on long-term studies to assess the cumulative impacts of climatic changes on nitrogen availability and ecosystem health to guide policies and management practices for sustainable development.
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Open AccessArticle
New Nitrogen Use Efficiency Indices for Biomass Formation and Productivity in Green Beans Under Foliar Fertilization with Molybdenum Nanofertilizer
by
Ezequiel Muñoz-Márquez, Juan Manuel Soto-Parra, Ramona Pérez-Leal and Esteban Sanchez
Nitrogen 2024, 5(3), 667-687; https://doi.org/10.3390/nitrogen5030044 - 5 Aug 2024
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Most crops are fertilized with high amounts of nitrogen, and have an alarmingly low utilization efficiency. For this reason, the coordination between the fertilizer contribution and the nitrogen requirements of the crop is very important. Therefore, the objective of the present study was
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Most crops are fertilized with high amounts of nitrogen, and have an alarmingly low utilization efficiency. For this reason, the coordination between the fertilizer contribution and the nitrogen requirements of the crop is very important. Therefore, the objective of the present study was to establish new indices to determine nitrogen use efficiency (NUE), and to define the amount of assimilated nitrogen, which is used for the formation of green bean plant organs, fertilized with molybdenum nanofertilizer applied foliarly, and combined with edaphic fertilization of ammonium nitrate. The plants were grown in a greenhouse covered with anti-aphid mesh and irrigated with nutrient solution. Three sources of foliar molybdenum (Nanofertilizer, molybdenum Chelate and Sodium Molybdate) were applied in four doses of 0, 5, 10 and 20 ppm Mo, complemented with edaphic fertilization of NH4NO3 (0, 3, 6 and 12 mM of N). As results, the NUE indices showed that with the application of the nanofertilizer, the total biomass production increased 41.65% more than with the application of the chelate, and 36.84% more than with the application of molybdate. In summary, the dose that presented the highest efficiency was 6 mM-N with 10 ppm-Mo. Finally, it is concluded that the use of NUE indices is an important approach that evaluates the fate of nitrogen and accurately estimates plant yield.
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