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Nitrogen, Volume 5, Issue 2 (June 2024) – 14 articles

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15 pages, 2912 KiB  
Article
Spectral Index-Based Estimation of Total Nitrogen in Forage Maize: A Comparative Analysis of Machine Learning Algorithms
by Aldo Rafael Martínez-Sifuentes, Ramón Trucíos-Caciano, Nuria Aide López-Hernández, Enrique Miguel-Valle and Juan Estrada-Ávalos
Nitrogen 2024, 5(2), 468-482; https://doi.org/10.3390/nitrogen5020030 (registering DOI) - 29 May 2024
Viewed by 111
Abstract
Nitrogen plays a fundamental role as a nutrient for the growth of leaves and the process of photosynthesis, as it directly influences the quality and yield of corn. The importance of knowing the foliar nitrogen content through Machine Learning algorithms will help determine [...] Read more.
Nitrogen plays a fundamental role as a nutrient for the growth of leaves and the process of photosynthesis, as it directly influences the quality and yield of corn. The importance of knowing the foliar nitrogen content through Machine Learning algorithms will help determine the efficient use of nitrogen fertilization in a context of sustainable agronomic management by avoiding Nitrogen loss and preventing it from becoming a pollutant for the soil and the atmosphere. The combination of machine learning algorithms with vegetation spectral indices is a new practice that helps estimate parameters of agricultural importance such as nitrogen. The objective of the present study was to compare random forest and neural network algorithms for estimating total plant nitrogen with spectral indices. Five spectral indices were obtained from remotely piloted aircraft systems and analyzed by mean, maximum and minimum from each sample plot to finally obtain 15 indices, and total nitrogen was estimated from the georeferenced points. The most important variables were selected with backward, forward and stepwise methods and total nitrogen estimates by laboratory were compared with random forest models and artificial neural networks. The most important indices were NDREmax and TCARImax. Using 15 spectral indices, total nitrogen with a variance of 79% and 81% with random forest and artificial neural network, respectively, was estimated. And only using NDREmax and TCARmax indices, 73% and 79% were explained by random forest and artificial neural network, respectively. It is concluded that it is possible to estimate nitrogen in forage maize with two indices and it is recommended to analyze by phenological stage and with a greater number of field data. Full article
(This article belongs to the Special Issue Nitrogen Management and Water-Nitrogen Interactions in Agriculture)
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13 pages, 1223 KiB  
Article
Efficiency of Nitrogen Fertilization in Millet Irrigated with Brackish Water
by Geocleber Gomes de Sousa, Francisco Hermeson Rodrigues Costa, José Thomas Machado de Sousa, Murilo de Sousa Almeida, Silas Primola Gomes, Claudivan Feitosa de Lacerda, Thales Vinicius de Araújo Viana, Samuel de Oliveira Santos, Francisco Barroso da Silva Junior, Fernando Bezerra Lopes, Sílvio Carlos Ribeiro Vieira Lima and Alexsandro Oliveira da Silva
Nitrogen 2024, 5(2), 455-467; https://doi.org/10.3390/nitrogen5020029 (registering DOI) - 29 May 2024
Viewed by 102
Abstract
Nitrogen fertilization can provide greater nutritional support and mitigate salt stress in the millet crop. The aim of this study was to evaluate the physiological responses and agronomic performance of millet crop subjected to nitrogen fertilization and irrigation water salinity. The study was [...] Read more.
Nitrogen fertilization can provide greater nutritional support and mitigate salt stress in the millet crop. The aim of this study was to evaluate the physiological responses and agronomic performance of millet crop subjected to nitrogen fertilization and irrigation water salinity. The study was carried out in a greenhouse, using a completely randomized design in a 5 × 2 factorial scheme, with four replications, with five doses of nitrogen (40; 60; 80; 100 and 120 kg ha−1 of N), and two levels of electrical conductivity for the irrigation water: 0.3 and 4.0 dS m−1. We concluded that salt stress increased leaf sodium levels and had a negative impact on stalk and panicle dry mass, leaf gas exchange, mineral element concentrations (K, P, and Ca), and water use efficiency. The use of lower-salinity water associated with increased nitrogen fertilization provides greater stalk and panicle dry mass, photosynthesis, water use efficiency, chlorophyll index, leaf potassium concentration, and biomass production. The adverse effects of salt stress were evident in decreased transpiration and stomatal conductance, alongside reductions in leaf phosphorus and calcium levels, coupled with elevated leaf sodium concentrations, particularly as nitrogen fertilization rates increased in potted millet plants. These findings offer insights for devising strategies aimed at mitigating the detrimental effects of salt stress on millet plant nutrition through targeted nitrogen fertilization approaches. Full article
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16 pages, 2383 KiB  
Article
Changes in Amino Acids Profile and Uptake on Maize Seedlings Treated with Protein Hydrolysates and Humic Substances
by Luciano Pasqualoto Canellas, Natália Aguiar Canellas, Fábio Val, Riccardo Spaccini, Pierluigi Mazzei and Fabio Lopes Olivares
Nitrogen 2024, 5(2), 439-454; https://doi.org/10.3390/nitrogen5020028 - 26 May 2024
Viewed by 279
Abstract
Protein hydrolysates (PH) and humic substances (HS) are biostimulants that promote crop growth. Despite the widening of knowledge and insights provided by research activities over the past thirty years, there are still uncertainties concerning the possible direct absorption by plants of organic nitrogen [...] Read more.
Protein hydrolysates (PH) and humic substances (HS) are biostimulants that promote crop growth. Despite the widening of knowledge and insights provided by research activities over the past thirty years, there are still uncertainties concerning the possible direct absorption by plants of organic nitrogen as amino acids (AA) delivered as PH and the role of HS. This study aimed to assess the impact of PH treatment on the amino acid profile of maize seedlings and the influence of HS on amino acid uptake. Maize seedlings were treated with either PH from the yeast of the sugarcane fermentation process or a synthetic mixture of amino acids mimicking the PH composition using dual-labeled amino acids (13C, 15N glutamic acid) combined with commercially available humic substances. The amino acid profile was analyzed using HPLC, and plant tissues were examined for 15N using nuclear magnetic resonance (NMR) and mass spectrometry. The application of PH stimulated maize growth, with a more significant effect observed in the presence of humic substances. The treatments significantly altered the plants’ total amino acid content and composition profile. Maize seedlings actively uptake amino acids, representing 21% of the total nitrogen composition. The ascertained improvement of amino acid uptake stimulated by humic substances is associated with their effect on the differential expression of amino permease transporters and plasma membrane H+-ATPase. PH and amino acids enhance maize growth by significantly increasing amino acid uptake. The addition of humic substances further improved the biostimulant effects. Full article
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13 pages, 2691 KiB  
Article
Influence of an Organic Fertilizer on Agronomic Characteristics and Herbaceous Plant Diversity in a Greek Ecosystem: The Case of Cretan Dittany (Origanum dictamnus L.)
by Aikaterini Molla, Alexandra D. Solomou, Anastasia Fountouli, Evaggelia Chatzikirou, Emmanouil Stamatakis, Petros Stamatakis and Elpiniki Skoufogianni
Nitrogen 2024, 5(2), 426-438; https://doi.org/10.3390/nitrogen5020027 - 11 May 2024
Viewed by 454
Abstract
In recent years, there has been a growing tendency towards using organic fertilizers instead of chemical ones. This study aimed to evaluate the influence of the organic fertilizer, Prima Humica, on agronomic characteristics and herbaceous plant diversity on Origanum dictamnus (Dittany) cultivation. A [...] Read more.
In recent years, there has been a growing tendency towards using organic fertilizers instead of chemical ones. This study aimed to evaluate the influence of the organic fertilizer, Prima Humica, on agronomic characteristics and herbaceous plant diversity on Origanum dictamnus (Dittany) cultivation. A field experiment was carried out in Kalo Xorio (Lasithi, Crete) and included three different nitrogen organic fertilization schemes: 0 g/plant (T0—unfertilized), 300 g/plot (T1), and 600 g/plot (T2). Plant height, fresh and dry weight, Leaf Area Index (LAI), and plant diversity during the growing season were measured. The results showed that when the T2 treatment was compared with the unfertilized and the T1 fertilizer, the increase in plant height ranged between 9.18% and 40.61%. Moreover, the total fresh and dry weight were positively affected by the T2 treatment. The total fresh and dry weight varied from 111.6 to 239.8 g per plant and from 36.7 to 77.6 g per plant, respectively. Furthermore, LAI was ameliorated using the T2 fertilizer scheme. Concerning plant diversity, a key finding in this study is that the O. dictamnus ecosystem favors herbaceous plant species richness and Shannon’s diversity index. In total, 18 plant species in the O. dictamnus ecosystem were recorded in the study area. The most frequently occurring plants were Anthemis arvensis L. and Piptatherum miliaceum (L.) Coss. Finally, the highest Shannon’s diversity index of herbaceous plants was detected using the T2 fertilizer scheme. Full article
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17 pages, 3638 KiB  
Article
Optimization of Ammonia Nitrogen Removal and Recovery from Raw Liquid Dairy Manure Using Vacuum Thermal Stripping and Acid Absorption Process: A Modeling Approach Using Response Surface Methodology
by Srijana Sapkota, Arif Reza and Lide Chen
Nitrogen 2024, 5(2), 409-425; https://doi.org/10.3390/nitrogen5020026 - 9 May 2024
Viewed by 536
Abstract
Dairy manure adds a substantial amount of nitrogen to wastewater due to its high levels of associated nutrients. Removal and recovery of ammonia nitrogen (NH3-N) from raw liquid dairy manure (RLDM) is greatly valued. This study was focused on the vacuum [...] Read more.
Dairy manure adds a substantial amount of nitrogen to wastewater due to its high levels of associated nutrients. Removal and recovery of ammonia nitrogen (NH3-N) from raw liquid dairy manure (RLDM) is greatly valued. This study was focused on the vacuum thermal stripping–acid absorption (VTS-AA) process for NH3-N from RLDM, followed by modeling and optimization. Using the response surface methodology (RSM)-based central composite design (CCD) approach, the critical operational parameters of the vacuum thermal stripping process, including temperature (50–70 °C), pH (9–11), vacuum pressure (35–55 kPa), and treatment time (60–90 min), were optimized. With the specified parameters set at temperature 69.9 °C, pH 10.5, vacuum pressure 53.5 kPa, and treatment time 64.2 min, the NH3-N removal efficiency attained was 98.58 ± 1.05%, aligning closely with the model prediction. Furthermore, the recovered ammonium sulfate ((NH4)2SO4) closely matched their commercial counterparts, confirming the effectiveness of the VTS-AA process in recovering NH3-N from RLDM. The distinct advantage of the employed technology lies in the concurrent energy demand reduction achieved by introducing a vacuum system. These findings contribute valuable insights into the practical implementation of the VTS-AA process for treating raw dairy manure, particularly in large-scale operational contexts. Full article
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23 pages, 4823 KiB  
Article
Does the Amount of Pre-Sowing Nitrogen Fertilization Affect Sugar Beet Root Yield and Quality of Different Genotypes?
by Ivana Varga, Antonela Markulj Kulundžić, Monika Tkalec Kojić and Manda Antunović
Nitrogen 2024, 5(2), 386-408; https://doi.org/10.3390/nitrogen5020025 - 8 May 2024
Viewed by 529
Abstract
There has always been a specific focus on nitrogen fertilization in sugar beet production due to its important effect on sugar beet root yield and quality. For stable sugar beet growth and satisfactory root yield and quality, balanced N fertilization is crucial. Thus, [...] Read more.
There has always been a specific focus on nitrogen fertilization in sugar beet production due to its important effect on sugar beet root yield and quality. For stable sugar beet growth and satisfactory root yield and quality, balanced N fertilization is crucial. Thus, this study aimed to investigate spring N fertilization in two seasons as the following treatments: N0—control, N1—only pre-sowing fertilization, and N2—pre-sowing with topdressing. Four different genotypes were included in the study (Serenada, Colonia, Fred, and Danton). The experiment was set up in a plain area, belonging to the temperate climate zone in Eastern Croatia (Županja and Vrbanja), with the long-term mean (LTM) (March–October) air temperature around 16 °C and the total precipitation of 515 mm. Pre-sowing N fertilization had a smaller impact on root yield in the year with higher precipitation (31% higher than LTM). Therefore, the average yields with pre-sowing fertilization (N1) and pre-sowing fertilization with top dressing (N2) were very similar and were only 7% higher than those of the control. In a season with less rainfall (29% less than LTM), pre-sowing fertilization with top dressing (N2) had a more pronounced effect on the increase in sugar beet root yield, which was 17% higher compared to that of the control treatment. The sugar beet sucrose content and quality parameters (brei impurities, loss of sugar in molasses, extractable sugar) differed when N fertilization was applied among locations in both seasons. The white sugar yield was the highest at N2 treatment with pre-sowing and topdressing N fertilization. In general, according to the average of all locations and years of research, the Serenada hybrid achieved the highest average root yield (81.1 t ha−1), while Colonia exhibited the highest root sugar content (14.5%) and white sugar yield (9.7 t ha−1). Full article
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13 pages, 1300 KiB  
Article
Effects of Seasonal Variation on Nitrogen Use in Brazilian Cerrado Grass Communities
by Victor Camargo Keller, Erico Fernando Lopes Pereira-Silva, Sergio Tadeu Meirelles and Elisa Hardt
Nitrogen 2024, 5(2), 373-385; https://doi.org/10.3390/nitrogen5020024 - 24 Apr 2024
Viewed by 500
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Nitrogen Signaling in Plants)
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24 pages, 6167 KiB  
Review
Recent Advances in Application of 1D Nanomaterials for Photocatalytic Nitrogen Fixation
by Ragesh Nath R., Shamkumar P. Deshmukh, Sachin J. Kamble and Valmiki B. Koli
Nitrogen 2024, 5(2), 349-372; https://doi.org/10.3390/nitrogen5020023 - 22 Apr 2024
Viewed by 842
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, [...] Read more.
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. Full article
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20 pages, 1297 KiB  
Article
Crop Rotation and Nitrogen Fertilizer on Nitrate Leaching: Insights from a Low Rainfall Study
by Isabeli P. Bruno, Augusto G. Araújo, Gustavo H. Merten, Audilei S. Ladeira and Victor M. Pinto
Nitrogen 2024, 5(2), 329-348; https://doi.org/10.3390/nitrogen5020022 - 19 Apr 2024
Viewed by 617
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Nitrogen Management and Water-Nitrogen Interactions in Agriculture)
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14 pages, 670 KiB  
Article
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://doi.org/10.3390/nitrogen5020021 - 18 Apr 2024
Viewed by 790
Abstract
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 [...] Read more.
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. Full article
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14 pages, 3622 KiB  
Article
Whole Genome Analysis of Streptomyces spp. Strains Isolated from the Rhizosphere of Vitis vinifera L. Reveals Their Role in Nitrogen and Phosphorus Metabolism
by 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://doi.org/10.3390/nitrogen5020020 - 16 Apr 2024
Viewed by 1121
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Nitrogen Cycling and Bacterial Community)
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13 pages, 4585 KiB  
Article
Empirical Correlation between Electrical Conductivity and Nitrogen Content in Biochar as Influenced by Pyrolysis Temperature
by 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://doi.org/10.3390/nitrogen5020019 - 9 Apr 2024
Viewed by 897
Abstract
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). [...] Read more.
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. Full article
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22 pages, 2827 KiB  
Article
Assessing the Impact of Nitrogen Fertilization, Variety Selection, Year and Their Interaction on Wheat Yield and Yield Components
by Oussama Hnizil, Aziz Baidani, Ilham Khlila, Nasserelhaq Nsarellah and Ali Amamou
Nitrogen 2024, 5(2), 266-287; https://doi.org/10.3390/nitrogen5020018 - 9 Apr 2024
Viewed by 751
Abstract
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, [...] Read more.
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. Full article
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12 pages, 723 KiB  
Article
N Losses from an Andisol via Gaseous N2O and N2 Emissions Increase with Increasing Ruminant Urinary–N Deposition Rate
by 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://doi.org/10.3390/nitrogen5020017 - 22 Mar 2024
Viewed by 891
Abstract
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 [...] Read more.
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. Full article
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