Nitrogen

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12 pages, 2469 KiB

Open AccessArticle

Reduction of Nitrogen through Anaerobic Processes in Chinese Rice Paddy Soils

by Ahmed A. A. Aioub, Shuquan Jin, Jiezhang Xu and Qichun Zhang

Nitrogen 2024, 5(3), 655-666; https://doi.org/10.3390/nitrogen5030043 - 30 Jul 2024

Viewed by 889

Abstract

Comprehending the anaerobic nitrogen transformations, including denitrification, anaerobic ammonium oxidation (anammox), and anaerobic ammonium oxidation linked with iron reduction (Feammox) in soil, is essential for improving soil fertility and minimizing the environmental impacts of nitrogen loss. Despite this, research on anaerobic nitrogen transformations, [...] Read more.

Comprehending the anaerobic nitrogen transformations, including denitrification, anaerobic ammonium oxidation (anammox), and anaerobic ammonium oxidation linked with iron reduction (Feammox) in soil, is essential for improving soil fertility and minimizing the environmental impacts of nitrogen loss. Despite this, research on anaerobic nitrogen transformations, particularly Feammox in paddy soil, is sparse. This study examined soil denitrification, anammox, and Feammox, along with their respective contributions to nitrogen loss in paddy soil at various depths, under different fertilization and irrigation treatments. It utilized 15N isotope labeling to investigate the limiting factors of these anaerobic nitrogen transformations and their interactions. The findings showed that denitrification rates ranged from 0.41 to 2.12 mg N kg⁻¹ d⁻¹, while anammox rates ranged from 0.062 to 0.394 mg N kg⁻¹ d⁻¹, contributing 84.3% to 88.1% and 11.8% to 15.7% of total soil nitrogen loss, respectively. Denitrification was identified as the predominant pathway for nitrogen loss across different soil depths. Fertilization and irrigation had more pronounced impacts on anaerobic nitrogen transformations than did soil depth, potentially affecting these processes through both abiotic and biotic pathways. This study identified significant correlations among the three types of anaerobic nitrogen transformations. These findings offer a theoretical foundation for optimizing nitrogen management strategies to mitigate losses in agricultural systems. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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14 pages, 667 KiB

Open AccessArticle

Ammonium Fertilization Enhances Nutrient Uptake, Specifically Manganese and Zinc, and Growth of Maize in Unlimed and Limed Acidic Sandy Soil

by Asif Naeem, Philipp Deppermann and Karl H. Mühling

Nitrogen 2023, 4(2), 239-252; https://doi.org/10.3390/nitrogen4020017 - 19 Jun 2023

Cited by 5 | Viewed by 2399

Abstract

Although NH₄⁺ fertilization is known to acidify rhizosphere and enhance nutrient uptake, the effects on a nutrient-sufficient acidic soil amended with lime are not demonstrated. Thus, the influence of NH₄⁺ fertilization of an unlimed and limed (3 g calcium [...] Read more.

Although NH₄⁺ fertilization is known to acidify rhizosphere and enhance nutrient uptake, the effects on a nutrient-sufficient acidic soil amended with lime are not demonstrated. Thus, the influence of NH₄⁺ fertilization of an unlimed and limed (3 g calcium carbonate per kg soil) acidic soil on the nutrient uptake and growth of maize was studied in comparison to NH₄NO₃ fertilization. The pH of limed rhizosphere soil was about two units higher than that of the unlimed soil. The maize plants were grown in pots under greenhouse conditions for about two months. The results showed that the pH of the NH₄⁺-fertilized unlimed and limed soil was 0.54 and 0.15 units lower than the NH₄NO₃-fertilized soil. Liming negatively affected shoot and root dry matter production, whereas the NH₄⁺-fertilized plants produced higher dry matter than the NH₄NO₃-fertilized plants, with significant difference of 28% in the limed soil only. Liming decreased Fe concentration in rhizosphere soil from 99 to 69 mg kg⁻¹ and decreased plant-available Mn the most (71%), whereas the NH₄⁺-fertilized unlimed and limed soil had 48% and 21% higher Mn concentration than the respective NH₄NO₃-fertilized soils. Similarly limed rhizosphere soil had 50% lower plant-available Zn concentration than the unlimed soil, and the NH₄⁺-fertilized soil had an 8% higher Zn concentration than the NH₄NO₃-fertilized unlimed soil. The liming negatively affected P, K, Mn, and Zn concentrations and contents in maize shoot to a lower degree in the NH₄⁺-fertilized soil, whereas the positive effect of NH₄⁺ on the nutrient concentration and contents was vigorous in the unlimed soil than the limed soil. It is concluded that NH₄⁺ fertilization could be beneficial in enhancing nutrient uptake and growth of maize in both acidic and alkaline soils, despite the higher inherent plant-available concentrations of the nutrient in soil. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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21 pages, 5417 KiB

Open AccessArticle

Cover Crop Termination Method and N Fertilization Effects on Sweet Corn Yield, Quality, N Uptake, and Weed Pressure

by Sachina Sunuwar, Arthur Siller, Samantha Glaze-Corcoran and Masoud Hashemi

Nitrogen 2023, 4(1), 37-57; https://doi.org/10.3390/nitrogen4010005 - 25 Jan 2023

Viewed by 1926

Abstract

Cover cropping is vital for soil health. Timing and method of termination are major factors influencing the agroecological benefits of cover crops. Delay in the termination of cover crops results in greater biomass production. Likewise, incorporation of cover crops during termination often speeds [...] Read more.

Cover cropping is vital for soil health. Timing and method of termination are major factors influencing the agroecological benefits of cover crops. Delay in the termination of cover crops results in greater biomass production. Likewise, incorporation of cover crops during termination often speeds residue mineralization compared to no-till systems. We used four termination strategies for a late-terminated winter rye–legume mix (in tilled and no-till systems) and four N application rates in the succeeding sweet corn crop to examine how cover crop termination affected N response in sweet corn as well as the independent effects of N application rate and cover crop termination method. The experiment was conducted using a randomized complete block design with four replications. Increasing N fertilization up to 144 kg N ha⁻¹ promoted yield and quality in sweet corn as well as summer weed growth. The cover crop termination method did not affect sweet corn response to N fertilizer. This suggests that when rye is terminated late in the spring before planting cash crops, the incorporation of its residues may not greatly affect the soil N dynamics. This indicates that decisions to incorporate rye residues may be taken by farmers with an eye mainly towards management issues such as weed control, environmental impacts, and soil health. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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11 pages, 921 KiB

Open AccessArticle

Evaluation of Alkaline Hydrolyzable Organic Nitrogen as an Index of Nitrogen Mineralization Potential of Some Coastal Savannah Soils of Ghana

by Daniel E. Dodor, Mohamed S. Kamara, Abena Asamoah-Bediako, Samuel G. K. Adiku, Dilys S. MacCarthy, Samuel K. Kumahor and Dora Neina

Nitrogen 2022, 3(4), 652-662; https://doi.org/10.3390/nitrogen3040043 - 16 Dec 2022

Cited by 5 | Viewed by 2616

Abstract

Numerous biological and chemical methods have been proposed over the years for estimating the nitrogen (N) mineralization capacity of soils; however, none of them has found general use in soil fertility testing. The efficacy of a recently proposed alkaline hydrolysis method for assessing [...] Read more.

Numerous biological and chemical methods have been proposed over the years for estimating the nitrogen (N) mineralization capacity of soils; however, none of them has found general use in soil fertility testing. The efficacy of a recently proposed alkaline hydrolysis method for assessing N availability in soils compared with the standard long-term incubation technique for determining potentially available N was evaluated. The nitrogen mineralization of 12 surface soils incubated under aerobic conditions at 25 °C for 26 weeks was determined. Field-moist soils were direct-steam distilled with 1 M KOH or 1 M NaOH; the NH₃ released was trapped in boric acid, and its concentration was determined successively every 5 min for 40 min. The cumulative N mineralized or hydrolyzed was fitted to the first-order exponential equation to determine the potentially mineralizable N (N_o) and an analogous “potentially hydrolyzable N (N_max)” for the soils. The flush of CO₂ (fCO₂) following the rewetting and incubation of air-dried soils under aerobic conditions for 3 days was also determined. The results showed that the N_max values differed considerably among the soils, indicating differences in the chemical nature and reactivity of the organic N content of the soils, and were significantly correlated with N_o and fCO₂ values. The estimated N_max and N_o values ranged from 105 to 371 mg N kg⁻¹ and 121 to 292 mg kg⁻¹, respectively. Based on the simple and inexpensive nature of the alkaline hydrolysis procedure, the reduction in the incubation time required to obtain N_o (months to minutes), and the strong association between N_max and N_o, we concluded that N_max is a good predictor of the biologically discrete and quantifiable labile pool of mineralizable soil organic N (ON), and the use of the alkaline hydrolyzable ON as a predictor of N_o merits consideration for routine use in soil testing laboratories for estimating the N-supplying capacity of soils. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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14 pages, 491 KiB

Open AccessArticle

Predicting Soil Nitrogen Availability for Maize Production in Brazil

by Lucas Boscov Braos, Roberta Souto Carlos, Fernando Kuhnen, Manoel Evaristo Ferreira, Richard Lesley Mulvaney, Saeed Ahmad Khan and Mara Cristina Pessôa da Cruz

Nitrogen 2022, 3(4), 555-568; https://doi.org/10.3390/nitrogen3040036 - 10 Oct 2022

Cited by 6 | Viewed by 2148

Abstract

Maize (Zea mays L.) is a crop widely cultivated in the state of São Paulo, and the sustainable management of nitrogen (N) nutrition is crucial to improving productivity and the environment, which calls for a reliable means of predicting potentially available soil [...] Read more.

Maize (Zea mays L.) is a crop widely cultivated in the state of São Paulo, and the sustainable management of nitrogen (N) nutrition is crucial to improving productivity and the environment, which calls for a reliable means of predicting potentially available soil N. A study was undertaken to evaluate and compare biological and chemical indices of potential N availability for a diverse set of 17 soils collected in the northwest region of São Paulo state. For this purpose, mineralization assays were performed at three distinct temperatures, and chemical assessments were carried out using the Illinois Soil Nitrogen Test (ISNT) and by fractionation of hydrolysable soil N. In addition, a greenhouse experiment was conducted to determine dry matter and N accumulation in the aboveground parts of maize plants. Potentially available N estimated by the incubation methods increased with increasing temperature and was strongly correlated with N uptake (r = 0.90). Hydrolysable N fractions varied widely among the soils studied and were more variable for amino sugar N than for other fractions. Potentially available N estimated by the ISNT was highly correlated with hydrolysable amino acid N and amino sugar N (r = 0.95–0.96) and also with plant dry matter accumulation (r = 0.82) and N uptake (r = 0.93). The ISNT has potential to improve fertilizer N recommendations for maize production in Brazil, provided that the test values are interpreted relative to an appropriate calibration database, planting density, and other factors affecting crop N requirement. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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14 pages, 643 KiB

Open AccessArticle

Agronomic and Economic Evaluations of N Fertilization in Maize under Recent Market Dynamics

by Yesuf Assen Mohammed, Russ W. Gesch, Jane M. F. Johnson and Steve W. Wagner

Nitrogen 2022, 3(3), 514-527; https://doi.org/10.3390/nitrogen3030033 - 1 Sep 2022

Cited by 10 | Viewed by 2282

Abstract

An online calculator is available to determine economic optimum nitrogen rate (EONR) for maize (Zea mays L.) production in the USA Corn Belt. For Minnesota, this calculator considers nitrogen (N) fertilizer cost, maize grain price and crop history, and produces a statewide [...] Read more.

An online calculator is available to determine economic optimum nitrogen rate (EONR) for maize (Zea mays L.) production in the USA Corn Belt. For Minnesota, this calculator considers nitrogen (N) fertilizer cost, maize grain price and crop history, and produces a statewide N rate based on maximum economic return to N (MRTN). However, a clear precipitation and temperature gradient, and soil heterogeneity across the state, and recent changes in fertilizer cost and maize grain price require the comparison of EONR from this calculator with results from field study. The objectives of this research were to determine the agronomic and economic benefits of basal and split application of N fertilizer on maize grain yield and yield components and compare EONR from field study with N recommendation from the online calculator. The nitrogen fertilizer rate for the field study ranged from 0 to 224 kg N ha⁻¹, either split or all applied at planting. The results showed that there were no interaction effects of N rate by time or N rate by year on maize grain yield. Maize grain yield had a quadratic response to N rate, and agronomic maximum grain yield peaked at 205 kg N ha⁻¹. The EONR from the field study was 168 kg N ha⁻¹ and it remained stable under a wide range of economic analysis scenarios with net benefit reaching up to 2474 USD ha⁻¹. The N rate from the online calculator at MRTN was 151 kg N ha⁻¹ and this rate may cause N deficiency in maize resulting in a yield penalty compared with the field study results. The field study was performed under specific soil and climatic conditions. Therefore, extensive research under various soil types, agronomic management practices and climatic conditions is warranted to evaluate the online calculator performance and its reliability as a precision tool for N fertilizer management in maize production. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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18 pages, 4562 KiB

Open AccessArticle

Impact of Plant-Based Amendments on Water-Soluble Nitrogen Release Dynamics in Cultivated Peatlands

by Vincent Marmier, Jacynthe Dessureault-Rompré, Emmanuel Frossard and Jean Caron

Nitrogen 2022, 3(3), 426-443; https://doi.org/10.3390/nitrogen3030028 - 23 Jul 2022

Cited by 4 | Viewed by 1957

Abstract

Drained cultivated peatlands have been an essential agricultural resource for many years. To slow and reduce the degradation of these soils, which increases with drainage, the use of plant-based amendments (straw, wood chips, and biochar) has been proposed. Literature on the effects of [...] Read more.

Drained cultivated peatlands have been an essential agricultural resource for many years. To slow and reduce the degradation of these soils, which increases with drainage, the use of plant-based amendments (straw, wood chips, and biochar) has been proposed. Literature on the effects of such amendments in cultivated peatlands is scarce, and questions have been raised regarding the impact of this practice on nutrient cycling, particularly nitrogen (N) dynamics. By means of a six-month incubation experiment, this study assessed the effects of four plant-based amendments (biochar, a forest mix, willow, and miscanthus) on the release kinetics of water-soluble N pools (mineral and organic) in two histosols of differing degrees of decomposition (Haplosaprist and Haplohemist). The amendment rate was set at 15 Mg ha⁻¹ on a dry weight basis. The N release kinetics were significantly impacted by soil type and amendment. Miscanthus and willow were the amendments that most reduced the release of soluble organic N (SON) and mineral N (minN). The addition of plant-based amendments reduced the total amount of released N pools during the incubation (cumulative N pools) by 50.3 to 355.2 mg kg⁻¹, depending on the soil type, the N pool, and the type of amendment. A significant relationship was found between microbial biomass N, urease activity, and the cumulative N at the end of the incubation. The results showed that the input of plant-based amendments in cultivated peatland decreases N release, which could have a beneficial impact by decreasing N leaching; however, it could also restrict crop growth. Further research is needed to fully assess the impact of such amendments used in cultivated peatlands on N and on C fluxes at the soil–plant and soil–atmosphere interfaces to determine if they constitute a long-term solution for more sustainable agriculture. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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8 pages, 1128 KiB

Open AccessPerspective

Secondary Immobilization as a Phase of N mineralization Dynamics of Soil Organic Inputs

by Panagiotis Dalias and Anastasis Christou

Nitrogen 2022, 3(4), 600-607; https://doi.org/10.3390/nitrogen3040039 - 1 Nov 2022

Cited by 1 | Viewed by 2635

Abstract

Current understanding of nitrogen (N) mineralization from organic soil inputs considers three alternative processes: immediate net mineralization of N, net immobilization followed by net mineralization, or exclusively net immobilization. The three processes are compatible and linked with the C:N ratio rule. However, research [...] Read more.

Current understanding of nitrogen (N) mineralization from organic soil inputs considers three alternative processes: immediate net mineralization of N, net immobilization followed by net mineralization, or exclusively net immobilization. The three processes are compatible and linked with the C:N ratio rule. However, research evidence from a number of incubation studies incorporating processed materials like manures, composts, manure composts, or already decomposed plant residues suggest the presence of a second N immobilization phase. The mechanisms and conditions of this process, which is against the prevailing theory of soil N cycling, have not been ascertained, but they should most likely be attributed to impeded dead microbial biomass turnover. The transfer of mineral forms of N to the organic N pool may reasonably be explained by the chemical stabilization of nitrogenous compounds with secondary products of lignin degradation, which occurs late after incorporation of an organic input in soil. Secondary immobilization questions the reliability of the C:N ratio and most likely of other quality indices if proved to be real, even to some extent, while it may also have significant consequences on the management of soil organic additives applied as fertilizers. Full article

(This article belongs to the Special Issue Soil Nitrogen Supply: Linking Plant Available N to Ecosystems Functions and Productivity, 2nd Edition)

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