Next Issue
Volume 1, December

Nitrogen, Volume 1, Issue 1 (September 2020) – 7 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Select all
Export citation of selected articles as:
Article
Low-Cost Multispectral Sensor Array for Determining Leaf Nitrogen Status
Nitrogen 2020, 1(1), 67-80; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010007 - 25 Aug 2020
Cited by 2 | Viewed by 1026
Abstract
A crop’s health can be determined by its leaf nutrient status; more precisely, leaf nitrogen (N) level, is a critical indicator that carries a lot of worthwhile nutrient information for classifying the plant’s health. However, the existing non-invasive techniques are expensive and bulky. [...] Read more.
A crop’s health can be determined by its leaf nutrient status; more precisely, leaf nitrogen (N) level, is a critical indicator that carries a lot of worthwhile nutrient information for classifying the plant’s health. However, the existing non-invasive techniques are expensive and bulky. The aim of this study is to develop a low-cost, quick-read multi-spectral sensor array to predict N level in leaves non-invasively. The proposed sensor module has been developed using two reflectance-based multi-spectral sensors (visible and near-infrared (NIR)). In addition, the proposed device can capture the reflectance data at 12 different wavelengths (six for each sensor). We conducted the experiment on canola leaves in a controlled greenhouse environment as well as in the field. In the greenhouse experiment, spectral data were collected from 87 leaves of 24 canola plants, subjected to varying levels of N fertilization. Later, 42 canola cultivars were subjected to low and high nitrogen levels in the field experiment. The k-nearest neighbors (KNN) algorithm was employed to model the reflectance data. The trained model shows an average accuracy of 88.4% on the test set for the greenhouse experiment and 79.2% for the field experiment. Overall, the result concludes that the proposed cost-effective sensing system can be viable in determining leaf nitrogen status. Full article
Show Figures

Figure 1

Article
Nitrogen Supplying Capacity of Animal Manures to the Soil in Relation to the Length of Their Storage
Nitrogen 2020, 1(1), 52-66; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010006 - 19 Aug 2020
Viewed by 739
Abstract
The study estimated the relationship between the amount of nitrogen (N) that will become available to plants after incorporation of soil of sheep/goat, cattle, swine, and poultry manure and the duration of manure storage prior to soil addition. Manures were periodically sampled from [...] Read more.
The study estimated the relationship between the amount of nitrogen (N) that will become available to plants after incorporation of soil of sheep/goat, cattle, swine, and poultry manure and the duration of manure storage prior to soil addition. Manures were periodically sampled from 12 storage piles that were kept for 12 months each and mixed with soil before laboratory incubation for 83 days. The percentage of organic N mineralized after soil incorporation was clearly greater for poultry, ranging between 41 and 85%, in relation to the other three manure types, for which maximum mineralization ranged between 4.5 and 66%. For sheep/goat, cattle, and swine, the interaction between mineralization and immobilization processes showed a distinct pattern with two phases of net N release during the twelve months of storage. The first was separated from the second by a period where mineralization was zeroed and appeared at about six months after storage initiation. It was recommended that farmers should preferably use well-digested manures that have been aerobically stored more than six months to avoid materials that provoke intense immobilization, unless problems associated with the use of fresh manure are managed. Full article
Show Figures

Figure 1

Review
Extent and Variation of Nitrogen Losses from Non-legume Field Crops of Conterminous United States
Nitrogen 2020, 1(1), 34-51; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010005 - 19 May 2020
Cited by 6 | Viewed by 1016
Abstract
Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN2O), ammonia volatilization (CNH3), [...] Read more.
Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN2O), ammonia volatilization (CNH3), and nitrate leaching (CNO3) during the growing season and associated crop, soil, and water management information were gathered to determine the extent and controls of these losses. This database consisted of 404, 26, and 358 observations of CN2O, CNH3, and CNO3 losses, respectively, from sixty-two peer-reviewed manuscripts. Corn (Zea mays) dominated the N loss studies. Losses ranged between −0.04 to 16.9, 2.50 to 50.9, and 0 to 257 kg N ha−1 for CN2O, CNH3 and CNO3, respectively. Most CN2O and CNO3 observations were reported from Colorado (n = 100) and Iowa (n = 176), respectively. The highest values of CN2O, and CNO3 were reported from Illinois and Minnesota states, and corn and potato (Solanum tuberosum), respectively. The application of anhydrous NH3 had the highest value of CN2O loss, and ammonium nitrate had the highest CNO3 loss. Among the different placement methods, the injection of fertilizer-N had the highest CN2O loss, whereas the banding of fertilizer-N had the highest CNO3 loss. The maximum CNO3 loss was higher for chisel than no-tillage practice. Both CN2O and CNO3 were positively correlated with fertilizer N application rate and the amount of water input (irrigation and rainfall). Fertilizer-N management strategies to control N loss should consider the spatio-temporal variability of interactions among climate, crop-and soil types. Full article
Show Figures

Figure 1

Article
Pollution Reduction in Throughflow from Vegetated and Non-Vegetated, Foam-Based Surfaces and Green Roofs
Nitrogen 2020, 1(1), 21-33; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010004 - 05 Aug 2018
Viewed by 1757
Abstract
The ability of foam-based unplanted and green surfaces (Aqualok™) to remove pollutants (total suspended solids (TSS), NO3, NH4, total organic carbon (TOC) and total phosphorus (TP)) from direct precipitation and roof runoff passing through the surfaces was assessed. The [...] Read more.
The ability of foam-based unplanted and green surfaces (Aqualok™) to remove pollutants (total suspended solids (TSS), NO3, NH4, total organic carbon (TOC) and total phosphorus (TP)) from direct precipitation and roof runoff passing through the surfaces was assessed. The assessments were conducted using unplanted Aqualok™ and planted Aqualok™ roof panels and a bioswale Aqualok™ installed on two Fire and Emergency Medical Service Stations (FEMSs) in Washington, D.C., USA. During a three-year period, impacts on water chemistry were evaluated by examining overall averages as well as performance over time. Upon installation, all Aqualok™ surfaces released a “pulse” of TSS and NO3, which decreased over time. TP concentrations from the planted panels were elevated relative to conventional roof runoff throughout the study. TOC was generally higher for planted Aqualok™ compared to unplanted Aqualok™, and did not decrease over time. Excluding the three months post-installation, TSS in throughflow from planted and unplanted Aqualok™ surfaces was 88% and 90% lower, respectively, than in runoff from a conventional tar and gravel roof. No significant differences between green surface throughflow and conventional roof runoff for NO3 or NH4 were observed. Full article
(This article belongs to the Special Issue Urbanization and Environmental Contaminants)
Show Figures

Figure 1

Review
Assessing Nitric Oxide (NO) in Higher Plants: An Outline
Nitrogen 2020, 1(1), 12-20; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010003 - 04 May 2018
Cited by 19 | Viewed by 2642
Abstract
Nitric oxide (NO) is a free radical and a component of the N-cycle. Nevertheless, NO is likewise endogenously produced inside plant cells where it participates in a myriad of physiological functions, as well as in the mechanism of response against abiotic and biotic [...] Read more.
Nitric oxide (NO) is a free radical and a component of the N-cycle. Nevertheless, NO is likewise endogenously produced inside plant cells where it participates in a myriad of physiological functions, as well as in the mechanism of response against abiotic and biotic stresses. At biochemical level, NO has a family of derived molecules designated as reactive nitrogen species (RNS) which finally can interact with different bio-macromolecules including proteins, lipids, and nucleic acids affecting their functions. The present review has the goal to provide a comprehensive and quick overview of the relevance of NO in higher plants, especially for those researchers who are not familiar in this research area in higher plants. Full article
Show Figures

Figure 1

Communication
Biosensor-Mediated In Situ Imaging Defines the Availability Period of Assimilatory Glutamine in Maize Seedling Leaves Following Nitrogen Fertilization
Nitrogen 2020, 1(1), 3-11; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010002 - 19 Jul 2017
Viewed by 2329
Abstract
The amino acid glutamine (Gln) is an important assimilatory intermediate between root-derived inorganic nitrogen (N) (i.e., ammonium) and downstream macromolecules, and is a central regulator in plant N physiology. The timing of Gln accumulation after N uptake by roots has been well characterized. [...] Read more.
The amino acid glutamine (Gln) is an important assimilatory intermediate between root-derived inorganic nitrogen (N) (i.e., ammonium) and downstream macromolecules, and is a central regulator in plant N physiology. The timing of Gln accumulation after N uptake by roots has been well characterized. However, the duration of availability of accumulated Gln at a sink tissue has not been well defined. Measuring Gln availability would require temporal measurements of both Gln accumulation and its reciprocal depletion. Furthermore, as Gln varies spatially within a tissue, whole-organ in situ visualization would be valuable. Here, the accumulation and subsequent disappearance of Gln in maize seedling leaves (Zea mays L.) was imaged in situ throughout the 48 h after N application to roots of N-deprived plants. Free Gln was imaged by placing leaves onto agar embedded with bacterial biosensor cells (GlnLux) that emit luminescence in the presence of leaf-derived Gln. Seedling leaves 1, 2, and 3 were imaged simultaneously to measure Gln availability across tissues that potentially vary in N sink strength. The results show that following root N fertilization, free Gln accumulates and then disappears with an availability period of up to 24 h following peak accumulation. The availability period of Gln was similar in all seedling leaves, but the amount of accumulation was leaf specific. As Gln is not only a metabolic intermediate, but also a signaling molecule, the potential importance of regulating its temporal availability within plant tissues is discussed. Full article
Show Figures

Figure 1

Editorial
Nitrogen: A New Cross-Disciplinary International Open Access Journal
Nitrogen 2020, 1(1), 1-2; https://0-doi-org.brum.beds.ac.uk/10.3390/nitrogen1010001 - 12 Jun 2017
Cited by 2 | Viewed by 2377
Abstract
Nitrogen, the element that is intimately associated with essentially all processes on Earth, is the broad focus of a new online, open access journal.[...] Full article
Next Issue
Back to TopTop