Ammonium Nitrate Research Articles

Electrocatalytic Nitrate Reduction on Metallic CoNi‐Terminated Catalyst with Industrial‐Level Current Density in Neutral Medium

AbstractGreen ammonia synthesis through electrocatalytic nitrate reduction reaction (eNO3RR) can serve as an effective alternative to the traditional energy‐intensive Haber‐Bosch process. However, achieving high Faradaic efficiency (FE) at industrially relevant current density in neutral medium poses significant challenges in eNO3RR. Herein, with the guidance of theoretical calculation, we successfully designed and constructed a metallic CoNi‐terminated catalyst on copper foam, which achieves an ammonia FE of up to 100% under industrial‐level current density and very low overpotential (‐0.15 V versus RHE) in a neutral medium. Multiple characterization results have confirmed that the maintained metal atom‐terminated surface through interaction with copper atoms plays a crucial role in reducing overpotential and achieving high current density. By constructing a home‐made gas stripping and absorption device, we demonstrated the complete conversion process for high‐purity ammonium nitrate products, displaying the potential for practical application. Our work suggests a sustainable and promising process towards directly converting nitrate‐containing pollutant solutions into practical nitrogen fertilizers.This article is protected by copyright. All rights reserved

Stacking nitrogen management practices: Combining double‐slot fertilizer injection with urease and nitrification inhibitors improves yields and reduces ammonia and nitrous oxide emissions

AbstractAmmonia loss following nitrogen fertilization can degrade air quality and impact human health, whereas nitrous oxide (N2O) can contribute to global warming and climate change. Mitigation practices that target only one N‐loss pathway can lead to pollution swamping; hence, practices targeting both N‐losses are required. A 3‐year field study examined fertilizer N‐placement (broadcast urea, single‐slot injection of urea ammonium nitrate [UAN], double‐slot UAN injection) and N‐metabolization inhibitors (with/without urease and nitrification inhibitors) impacts on NH3 and N2O losses and corn yields. Ammonia volatilization was reduced (p < 0.05) by 26% with single‐slot UAN injection (10.6 kg N ha−1) and by 63% with double‐slot UAN injection (5.32 kg N ha−1) compared to broadcast urea (14.3 kg N ha−1). Dual urease and nitrification inhibitors reduced NH3 volatilization (0.84–3.86 kg N ha−1) by 57%–92% compared to no inhibitors (5.32–14.3 kg N ha−1). When no inhibitors were applied, N2O emissions from slot injection (6.43–7.62 kg N ha−1) were 2.6–3.1 times greater than from broadcast urea (2.43 kg N ha−1). Dual inhibitors reduced N2O emissions by 43% from 6.43 to 3.66 kg N ha−1 with double‐slot injection. Double‐slot UAN injection increased corn grain yields (9.73 t ha−1) by 12%–13% compared to single‐slot UAN injection (8.71 t ha−1) and broadcast urea (8.6 t ha−1). Double‐slot UAN injection effectively decreased NH3 losses and increased corn grain yields, but dual N inhibitors were required to also reduce N2O. Hence, combined productivity and environmental benefits were accrued only when fertilizer containing urease and nitrification inhibitors was combined with double‐slot injection.

Hydrology and oxygen addition drive nutrients, metals, and methylmercury cycling in a hypereutrophic water supply reservoir

Impaired water quality in Mediterranean climate reservoirs is mainly associated with eutrophication and internal nutrient loading. To improve water quality in hypereutrophic Hodges Reservoir, California, United States, a hypolimnetic oxygenation system (HOS), using pure oxygen gas, was implemented in 2020. This study encompasses 3 years of pre-oxygenation data (2017–2019) and 2 years of post-oxygenation data (2020–2021) to understand the cycling of nutrients, metals, and mercury in the reservoir. During the wet year of 2017, mildly reduced conditions lasted until mid-summer in the enlarged reservoir. Nutrients and metals were seen in the hypolimnion including ammonia (~2 mg-N/L), manganese (~0.5 mg/L), phosphate (~0.5 mg-P/L), and sulfide (~10 mg/L). Production of methylmercury (MeHg), an important bioaccumulative toxin, was favored from April to June with a hypolimnetic accumulation rate of around 200 ng/m2·d. In contrast, the dry year of 2018 exhibited higher hypolimnetic concentrations of ammonia (~4 mg-N/L), manganese (~1 mg/L), phosphate (>0.5 mg-P/L), and sulfide (>15 mg/L). The rapid onset of highly reduced conditions in 2018 corresponded with low MeHg hypolimnetic accumulation (~50 ng/m2·d). It seems that mildly reduced conditions were associated with higher MeHg accumulation, while sulfidic, reduced conditions impaired inorganic mercury bioavailability for MeHg production and/or promoted microbial demethylation. Sulfide also appeared to act as a sink for iron via FeS precipitation, and potentially for manganese via MnS precipitation or manganese coprecipitation with FeS. Mass flux estimates for 2017–2019 indicate that much of the nutrients that accumulated in the hypolimnion moved via turbulent diffusion into the epilimnion at loading rates far exceeding thresholds predicting eutrophic conditions. After oxygenation in 2020–2021, the reservoir water column was highly oxidized but showed a lack of thermal stratification, suggesting reservoir operations in combination with HOS implementation inadvertently mixed the water column in this relatively shallow reservoir. Post-oxygenation, concentrations of ammonia, phosphate, manganese, and mercury in bottom waters all decreased, likely in response to oxidized conditions. Oxygenated bottom waters exhibited elevated nitrate, a byproduct of ammonia nitrification, and iron, a byproduct of FeS oxidation, indicating a lake-wide response to oxygenation.

Thermal annealing gradient tailoring on ammonium nitrate-capped CdS nanospheres synthesized via green precipitation

This study explores the impact of thermal annealing gradients on the physical properties and structural evolution of cadmium sulphide (CdS) nanospheres capped with ammonium nitrate as a modifier, which were fabricated through precipitation and subsequent annealing within 160-480 oC temperature range. The properties were characterized using X-ray diffraction (XRD), ultraviolet–visible (UV-Vis), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques The XRD results show that the present CdS exhibits superior crystallinity compared to pure CdS without capping, transitions from a cubic to a hexagonal phase structure, and increases in crystallite size and crystallinity with increasing temperature. The FTIR spectra postulate that a vibrational band presence evidences ammonium nitrate capping on CdS, with another distinct band that represents CdS in the lower wavenumber region, both intensifying at elevated temperatures. The UV-Vis analysis reveals that CdS exhibits strong ultraviolet (UV) absorption suitable for effective photoreaction under UV light and has a broader band gap compared to bulk CdS. SEM images show an extensive distribution of homogeneous nanospheres over the surface, with increased growth in size when capped with ammonium nitrate and at higher temperatures. As validated by TGA and DSC results, CdS with a smaller crystallite size improves thermal stability and energy transfer, as evidenced by reduced weight loss and a lower endothermic temperature, respectively. Varying the annealing temperature with ammonium nitrate capping can improve the structural and physical properties of CdS, which are beneficial for varied applications such as optoelectronics, energy storage, and photocatalysts.

Thermal Oxidation Reaction between NH3 and O3: Low-temperature Formation of an NH4+ -bearing Salt

NH3 has long been predicted to be an important component of outer solar system bodies, yet detection of this compound suggests a low abundance or absence on many objects where it would be expected. Here, we demonstrate that a thermally driven oxidation reaction between ammonia (NH3) and ozone (O3) in a H2O + NH3 + O3 mixture may contribute to the low abundance of NH3 on some of these objects, as this reaction efficiently occurs at temperatures as low as 70 K. We determined the overall activation energy for this reaction to be 17 ± 2 kJ mol−1, which is consistent with other chemical systems that react at cryogenic temperatures. The loss of these two compounds coincides with the formation of NH4+ and NO3− at low temperatures, both of which are observable with infrared spectroscopy. Warming our H2O + NH3 + O3 mixtures through sublimation, we find a number of higher-temperature phases, such as ammonia hemihydrate, nitric acid, and ammonium nitrate (NH4NO3). The most stable of these is NH4NO3, which remains on the substrate until temperatures near 270 K. The salt product within this sample contains near-infrared spectral features between 2.0 and 2.22 μm, which is a spectral region of interest for several outer solar system objects, including the Uranian satellites Miranda, Ariel and Umbriel, and Pluto's satellite Charon.

Highly Sensitive, Easy-to-Use, One-Step Detection of Peroxide-, Nitrate- and Chlorate-Based Explosives with Electron-Rich Ni Porphyrins.

Homemade explosives, such as peroxides, nitrates, and chlorates, are increasingly abused by terrorists, criminals, and amateur chemists. The starting materials are easily accessible and instructions on how to make the explosives are described on the Internet. Safety considerations raise the need to detect these substances quickly and in low concentrations using simple methods. Conventional methods for the detection of these substances require sophisticated, electrically operated, analytical equipment. The simpler chemical detection methods are multistep and require several chemicals. We have developed a simple, one-step method that works similarly to a pH test strip in terms of handling. The analytical reaction is based on an acid-catalyzed oxidation of an electron-rich porphyrin to an unusually stable radical cation and dication. The detection limit for the peroxide-based explosive triacetone triperoxide (TATP), which is very frequently used by terrorists, is 40 ng and thus low enough to detect the substance without direct contact via the gas phase. It is sufficient to bring the stick close to the substance to observe a color change from red to green. Nitrates and chlorates, such as ammonium nitrate, urea nitrate, or potassium chlorate, are detected by direct contact with a sensitivity of 85-350 ng. A color change from red to dark brown is observed. The test thus detects all homemade explosives and distinguishes between the extremely impact-, shock-, and friction-sensitive peroxides and the less sensitive nitrates and chlorates by color change of a simple test strip.

Effects of small-scale outplanting fertilization on conifer seedling growth and fungal community establishment

Forestry in Sweden largely relies on planting genetically improved seedlings after clear-cutting, and high survival and early growth of planted seedlings is vital for stand establishment, economic viability, and carbon sequestration. Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) are the two most important tree species in Swedish forest stands and both are associated with a variety of ectomycorrhizal fungi. While seedlings are generally not fertilized at outplanting, previous results have shown that fertilization with arginine phosphate can increase root growth and seedling survival. However, it is not clear how this affects fungal community composition on the roots of growing seedlings. In a planting experiment sampled after one and two growing seasons, we found that planting position had the largest effects both on seedling performance and on fungal community composition and provide insight into the early stages of fungal community succession on planted Norway spruce and Scots pine seedlings. Fungal taxa present on seedlings before planting persisted on seedling roots, while some degree of novel colonization by site indigenous taxa was observed. Fertilization modified the relative abundance of some fungal taxa but did not lead to significant changes in overall community composition. In terms of seedling performance, ammonium nitrate led to increased mortality while arginine phosphate improved root growth.

Improved anticorrosive performance of epoxy coating by introducing a one-pot synthesised nano-ceria embedded lamellar polyaniline/kaolinite hybrid

This study presents an innovative and uncomplicated approach to produce ceria-decorated lamellar polyaniline utilising interfacial oxidative polymerisation, with ceric ammonium nitrate as both the aniline oxidiser and the ceria precursor. The study found that a 1 % weight of active polyaniline/ceria hybrid provides better corrosion protection. The addition of barrier kaolinite further enhances the protective properties of the hybrid. The study also proposes a mechanism for the synergistic function of ceria, polyaniline, and kaolinite in achieving better protective performance of the coating in harsh saline environments. The EIS results indicate that the cPAni_K/epoxy material shows a high |Z|0.01Hz value of 5.59 × 1010 and two months of continuous exposure, the charge transfer resistance maintained at 2.14 × 109 Ω cm2. EIS results exhibited the durability of the coating in the harsh saline media. Corrosion rate shows that cPAni_K embedded epoxy displays the corrosion rate of the eight-order lower than that of the pristine epoxy coat. This newly developed active/passive hybrid pigment is eco-friendly and suitable for preventing corrosion in marine environments.

Cerric ammonium nitrate catalyzed eco-friendly green synthesis of chitosan Schiff base using PEG-400 as an anticancer agent against gastric cancer cells via inhibiting EGFR

The present study was conducted to scrutinize the pharmacological effect of oxazole-embedded Chitosan as an anticancer agent against gastric cancer cells. This compound was synthesized using the classical Schiff base reaction but utilizing the novel green chemical process where cerric ammonium nitrate (CAN) was used as a catalyst in the PEG-400 as solvent media. The target compound was obtained with an excellent yield at the catalyst loading of 5% CAN concentration in 15 min. The Kinase-Glo Plus luminescence kinase assay kit was used to determine the EGFR inhibitory activity of compound 1 where it showed potent activity with IC50 of 2.14 µM. Its effect was also determined on the cellular viability of the Human gastric cancer cell line (SGC7901), liver cancer cell line (HepG2), and lung cancer cell line (A549), where it exhibits potent activity against SGC7901. The compound further showed the concentration-dependent inhibitory effect on migration and invasion of SGC7901. In RT-qPCR analysis, the compound showed induction of apoptosis of SGC7901 cells possibly by restoring the expression of Bcl-2 and Bax near to normal, and inhibition of the mRNA expression of EGFR in a concentration-dependent manner. KEY WORDS: Schiff base, Chitosan, EGFR, mRNA, apoptosis, Bcl-2 Bull. Chem. Soc. Ethiop. 2024, 38(4), 1091-1101.                                                    DOI: https://dx.doi.org/10.4314/bcse.v38i4.22

The effects of contour-based rainwater harvesting and integrated nutrient management on maize yields in semi-arid regions of Zimbabwe

In the smallholder farming areas located in semi-arid regions of Zimbabwe, low and unreliable rainfall distribution and poor soil fertility are the major factors limiting crop production. The negative effects of these biophysical factors have been worsened by climate change. However, the major challenges have been the lack of sustainable, low-cost water and nutrient management technologies for these semi-arid regions. The objectives of this study were to evaluate the effects of contour-based rainwater harvesting (RWH) namely tied contours (TC), infiltration pits (IP) which were compared with the standard contour (STDC), and intergrated nutrient management (INM) where cattle manure was used as basal fertiliser and Ammonium Nitrate (AN) as top dressing, on maize yields. Results showed that fields with RWH had higher yields compared to STDC. Average maize yields were 2210 and 1792 kg ha−1 for TC and IP which were 88% and 52% above STDC (1176 kg ha−1) respectively. Increasing nitrogen (N) levels resulted in a further increase in maize yields. Return on investment was negative during drier years and was significantly higher in RWH systems compared with STDC during wet seasons. Farmers need to reduce mineral fertiliser application during dry seasons since little rainwater is captured. We conclude that contour based RWH and INM can be used as sustainable low cost methods of crop production. Higher fertiliser application rates when rainfall is limiting, do not result in increased return on investiment.

Complete ammonia oxidation (comammox) at pH 3–4 supports stable production of ammonium nitrate from urine

This study developed a new process that stably produced ammonium nitrate (NH4NO3), an important and commonly used fertilizer, from the source-separated urine by comammox Nitrospira. In the first stage, the complete conversion of ammonium to nitrate was achieved by comammox Nitrospira. In this scenario, the pH was maintained at 6 by adding external alkali, which also provided sufficient alkalinity for full nitrification. In the second stage, the NH4NO3 was produced directly by comammox Nitropsira by converting half of the ammonium in urine into nitrate. In this case, no alkali was added and pH automatically dropped and self-maintained at an extremely acidic level (pH 3–4). In both scenarios, negligible nitrite accumulation was observed, while the final product of the second stage contained ammonium and nitrate at the molar ratio of 1:1. The dominance of comammox Nitrospira over canonical ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) was systematically proved by the combination of 16S rRNA gene amplicon sequencing, quantitative polymerase chain reaction, and metagenomics. Notably, metagenomic sequencing suggested that the relative abundance of comammox Nitrospira was over 20 % under the acidic condition at pH 3–4, while canonical AOB and NOB were undetectable. Batch experiments showed that the optimal pH for the enriched comammox Nitrospira was ∼7, which could sustain their activity in a wider pH range from 4 to 8 surprisingly but lost activity at pH 3 and 9. The findings not only present an application potential of comammox Nitrospira in nitrogen recovery from urine wastewater but also report the survivability of comammox bacteria in acidic environments.

EVALUATION OF SELECTED MECHANICAL AND PHYSICAL PROPERTIES OF PARTICLEBOARDS CONTAINING WASTE PLASTICS

This article is focused on the research of particleboards (PB) composed of wood particles from spruce logs and recycled crushed plastic granulates. Crushed plastic granulates sized from 1.0 to 4.0 mm were obtained from worn automobiles by recycling, specifically painted and unpainted bumpers. The proportion of plastic granulate in the particleboards represented 10%, 15%, and 20% of the total weight of the composites. In the production of PB, urea-formaldehyde resin and paraffin emulsion were used as a binder and ammonium nitrate was used as a hardener. The aim of the article was to compare the selected properties of PB containing plastic filler with pure PB. Mechanical properties (tensile and bending strength), and physical properties (water absorption and thickness swelling) were evaluated according to EN 319, EN 310 and EN 317. Based on the results, it can be stated that the bending strength and physical properties of PB containing plastic filler were significantly better compared to pure PB. On the contrary, the tensile strength values were lower in most cases.

Local incomplete combustion emissions define the PM2.5 oxidative potential in Northern India

The oxidative potential (OP) of particulate matter (PM) is a major driver of PM-associated health effects. In India, the emission sources defining PM-OP, and their local/regional nature, are yet to be established. Here, to address this gap we determine the geographical origin, sources of PM, and its OP at five Indo-Gangetic Plain sites inside and outside Delhi. Our findings reveal that although uniformly high PM concentrations are recorded across the entire region, local emission sources and formation processes dominate PM pollution. Specifically, ammonium chloride, and organic aerosols (OA) from traffic exhaust, residential heating, and oxidation of unsaturated vapors from fossil fuels are the dominant PM sources inside Delhi. Ammonium sulfate and nitrate, and secondary OA from biomass burning vapors, are produced outside Delhi. Nevertheless, PM-OP is overwhelmingly driven by OA from incomplete combustion of biomass and fossil fuels, including traffic. These findings suggest that addressing local inefficient combustion processes can effectively mitigate PM health exposure in northern India.

Fertilizer Application Method Provides an Environmental-Friendly Nitrogen Management Option for Sugarcane

Abstract Purpose Nitrogen fertilizer management is an important agricultural tool that must be optimized to promote sustainable practices since the nitrogen-fertilizer recovery by plants (NRP) is low, leading to nitrogen losses to the environment. In sugarcane, N-fertilization has been investigated over the years but little attention has been given to N-fertilizer application methods. Sugarcane crop production and environmental impact regarding N-fertilizer application methods (i.e., applied onto the sugarcane straw layer and incorporated into the soil) were investigated in the present study aiming to achieve an environmental-friendly cropping system. Methods Sugarcane yield and NRP, N2O emissions, relevant components of the soil microbiological community and N-fertilizer retention in soil layers were quantified. The experiment was carried out in field conditions where N-fertilizer application methods using 15N-labelled ammonium nitrate (15NH415NO3) were compared to a control treatment with no N-fertilization. Results Incorporation of N-fertilizer into the soil increased the sugarcane yield by 17% (two-year average) compared to N-fertilizer applied onto the sugarcane straw layer, which was similar to control treatment. There was an increase in NRP-fertilizer of 79% due to the application of N-fertilizer incorporated into the soil. Furthermore, soil incorporation of N-fertilizer decreased N2O emission by 22% with the fertilizer N emission factor reduced four-fold. The N2O emissions were mostly associated with ammonium-oxidizing bacteria (AOB). Conclusions Our results show that application of N-fertilizer incorporated into the soil is an environmental-friendly N-fertilization management which will improve agricultural sustainability and reduce environmental impacts. Graphical Abstract

Nutritional and Molecular Studies of Alkaliphilic Tolerant Potential Amylase Producing Lactic Acid Bacteria Isolated from Indigenous Foods and Dumpsites

Alkaliphilic organisms are important in industries but most of these organisms are obtained from Bacillus species and the like that  require special scrutiny before use in fermentation of food related products. Lactic acid bacteria are generally regarded as safe (GRAS)  and are therefore readily applied in industrial fermentation with confidence. Due to high demand for the products of alkaliphilic organisms and industrial acceptability of lactic acid bacteria, there is a need to source for GRAS microorganisms that can withstand pH  ranges. The aim of this study was to isolate alkaliphilic tolerant lactic acid bacteria from fermented cassava mash, `ogi` and dump site  samples with a view to determining their nutritional requirement as well as molecular identity. Lactic acid bacteria were isolated from the  samples using standard methods. The isolates were subsequently characterized morphologically, biochemically and molecularly. Effects  of different carbon, nitrogen sources, initial temperature and pH as well as metal ions (Na+, Ca2+, Mg2+, Zn2+ and Cu2+) on the growth of  the isolates were examined. Data obtained were analyzed using one-way analysis of variance (ANOVA). Results obtained indicate that  extracted DNA sequence of A3, A7, A8 and A10 were related to those of Lactobacillus brevis FJ476121.1, Pediococcus acidilactici  CP096031.1, Pediococcus pentasaceus AB362605.1 and Pediococcus acidilactici CP053421.1 respectively with the sequences within the GenBank. 1% fructose elicited growth for all the bacteria detected except Lactobacillus brevis and ammonium nitrate was most preferred  by all the bacteria detected apart from Pediococcus pentasaceus strain. Lactobacillus brevis FJ476121.1 and Pediococcus acidilactici  CP053421.1 were the most alkaliphilic tolerant bacteria detected with OD of 0.285±0.04 and 0.198±0.04 respectively. Different metal ions  significantly influenced the growth of isolates in this study. The results in this study indicate potential applicability of the detected  bacteria for industrial processes.    

Investigation and mapping of toxic fumes produced by detonation of ANFO explosives in underground space

AbstractPost‐blast fumes are hazardous and known to cause severe health related issues of workers. Further, these harmful gases have a significant impact on the surrounding environment. Thus, it is imperative to have an in‐depth understanding of the real time detonation fume generation in underground space to avoid hazardous health risk of the worker. In this context, the mapping of toxic fume concentrations generated by the detonation of ANFO explosives in the actual field is a fascinating area of research that has a great environmental impact. This article examined the real‐time analysis of toxic fumes generated by ammonium nitrate fuel oil (ANFO) explosives at various locations of a metalliferous underground mine. Furthermore, detonation parameters of various ANFO explosive compositions were also studied at the mining site. On‐site blasting studies were performed with ANFO explosives, and post‐detonation fume measurements enabled us to map the CO and NOx concentrations in underground spaces. Toxic fumes like CO and NOx were analyzed before and after each blasting operation at different intervals, and found within the allowed limit as per the Directorate General of Mines Safety guidelines. Additionally, an empirical correlation has been established to evaluate the maximum detonation velocity based on the alteration of ammonium nitrate and fuel oil composition.

Desiccation and senification in the technology of cultivation of winter triticale varieties in the Middle Urals

Triticale is an artificially man-made culture that has both positive and negative signs and properties. One of such undesirable signs is the low resistance of the grain to germination during maturation. Therefore, the search for ways to reduce this phenomenon is an urgent issue. Pre-harvest treatment of crops, namely desiccation and senification, can be a solution to this problem. The purpose of the study, conducted in the conditions of the Udmurt Republic, geographically belonging to the Middle Urals, was a comparative study of the effect of desiccation and senification of crops on yield and grain quality of winter triticale. In a two-factor field experiment during the growing seasons 2021 and 2022, the varieties Izhevskaya 2 (control) and Beta, whose crops were treated with desiccant Sukhovey and seni- cants – 20 and 30% solutions of ammonium nitrate and ammonium sulfate, were studied. In the years of the study, the final stages of ontogenesis in triticale varieties took place in hot dry conditions. As a result, the effect of the studied substances did not affect the grain yield. When comparing the declared varieties, the yield advantage of the Beta variety was established due to the formation of larger grains and higher inflorescence productivity. At the same time, a greater accumulation of dry matter per unit area was characterized by a higher-growing variety Izhevskaya 2. In the course of the experiment the increase of the natural weight indices of winter triticale variety Beta by 7–9 g/l in the variants with the use of ammonium sulfate was revealed. Grain volume weight of the Izhevskaya 2 variety did not change under the influence of the studied methods.

Response of corn yield to water retaining agents, inhibitors, and corn stalks addition in semi-arid cropland,

Drought, excessive use of nitrogen fertilizer, and decline in soil organic matter threaten corn production. This study investigated the potential of water retaining agents, inhibitors, and corn stalks in enhancing soil physicochemical properties to bolster corn yield in semi-arid farmlands. In our study, polyacrylamide addition increased the content of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3–-N) in the seedling stage, exchangeable potassium (K) in the mature stage but decreased the content of available phosphorus (P) in the seedling stage. Potassium polyacrylate addition increased the content of NH4+-N and decreased the content of available P in the seedling stage. The addition of inhibitors decreased the content of NH4+-N and available P in the seedling stage, NO3–-N and available P in the jointing stage, and NH4+-N in the mature stage, respectively. Corn stalks returning could maintain soil moisture, decrease the content of NH4+-N in the seedling stage and exchangeable K in the mature stage, and increase the content of available P and exchangeable K in the seedling stage. Combined application of inhibitors and corn stalks could increase soil organic carbon (SOC) and ensure corn yield, which was the best fertilization mode in semi-arid cropland.

Influence of the Nitrogen Fertilization on the Yield, Biometric Characteristics and Chemical Composition of Stevia rebaudiana Bertoni Grown in Poland.

Stevia rebaudiana Bertoni is a plant native to South America that has gathered much interest in recent decades thanks to diterpene glycosides, called steviosides, which it produces. These compounds are characterised by their sweetness, which is 250-300 times higher than saccharose, and they contain almost no caloric value. Stevia is currently also grown outside the South American continent, in various countries characterised by warm weather. This research aimed to determine whether it is viable to grow Stevia rebaudiana plants in Poland, a country characterised by a cooler climate than the native regions for stevia plants. Additionally, the impact of adding various dosages and forms of nitrogen fertiliser was analysed. It was determined that Stevia rebaudiana grown in Poland is characterised by a rather low concentration of steviosides, although proper nitrogen fertilisation can improve various characteristics of the grown plants. The addition of 100 kg or 150 kg of nitrogen per hectare of the field in the form of urea or ammonium nitrate increased the yield of the stevia plants. The stevioside content can be increased by applying fertilisation using 100 kg or 150 kg of nitrogen per hectare in the form of ammonium sulfate. The total yield of the stevia plants grown in Poland was lower than the yield typically recorded in warmer countries, and the low concentration of steviosides in the plant suggests that more research about growing Stevia rebaudiana in Poland would be needed to develop profitable methods of stevia cultivation.

High-nitrogen fertilizer alleviated adverse effects of drought stress on the growth and photosynthetic characteristics of Hosta ‘Guacamole’

BackgroundSeveral plants are facing drought stress due to climate change in recent years. In this study, we aimed to explore the effect of varying watering frequency on the growth and photosynthetic characteristics of Hosta ‘Guacamole’. Moreover, we investigated the effect of high-nitrogen and -potassium fertilizers on alleviating the impacts of drought stress on the morphology, photosynthetic characteristics, chlorophyll fluorescence, fast chlorophyll a fluorescence transient, JIP-test parameters, and enzymatic and non-enzymatic scavenging system for reactive oxygen species (ROS) in this species.ResultsLeaf senescence, decreased chlorophyll contents, limited leaf area, and reduced photosynthetic characteristics and oxygen-evolving complex (OEC) activity were observed in Hosta ‘Guacamole’ under drought stress. However, high-nitrogen fertilizer (30-10-10) could efficiently alleviate and prevent the adverse effects of drought stress. High-nitrogen fertilizer significantly increased chlorophyll contents, which was higher by 106% than drought stress. Additionally, high-nitrogen fertilizer significantly improved net photosynthetic rate and water use efficiency, which were higher by 467% and 2900% than those under drought stress. It attributes that high-nitrogen fertilizer could reduce transpiration rate of leaf cells and stomatal opening size in drought stress. On the other hand, high-nitrogen fertilizer enhanced actual photochemical efficiency of PS II and photochemical quenching coefficient, and actual photochemical efficiency of PS II significantly higher by 177% than that under drought stress. Furthermore, high-nitrogen fertilizer significantly activated OEC and ascorbate peroxidase activities, and enhanced the performance of photosystem II and photosynthetic capacity compared with high-potassium fertilizers (15-10-30).ConclusionsHigh-nitrogen fertilizer (30-10-10) could efficiently alleviate the adverse effects of drought stress in Hosta ‘Guacamole’ via enhancing OEC activity and photosynthetic performance and stimulating enzymatic ROS scavenging system.