Nitrogen Fertilizer Sources Research Articles

Nitrogen Fertilizer Source, Timing, and Additives for Increased Efficiency

Nitrogen Fertilizer Source, Timing, and Additives for Increased Efficiency

Nitrogen fertilizers activate siderophore production by the common scab causative agent Streptomyces scabiei.

Streptomyces scabiei is the causative agents of common scab on root and tuber crops. Life in the soil imposes intense competition between soil-dwelling microorganisms and we evaluated here the antimicrobial properties of S. scabiei. Under laboratory culture conditions, increasing peptone levels correlated with increased growth inhibitory properties of S. scabiei. Comparative metabolomics showed that production of S. scabiei siderophores (desferrioxamines, pyochelin, scabichelin and turgichelin) increased with the quantity of peptone thereby suggesting that they participate in growth inhibition. Mass spectrometry imaging further confirmed that the zones of secreted siderophores and growth inhibition coincided. Moreover, either the repression of siderophore production or the neutralization of their iron-chelating activity both led to increased microbial growth. Replacement of peptone by natural nitrogen sources regularly used as fertilizers such as ammonium nitrate, ammonium sulfate, sodium nitrate, and urea also triggered siderophore production in S. scabiei. The observed effect is not mediated by alkalinization of the medium as increasing the pH without providing additional nitrogen sources did not induce siderophore production. The nitrogen-induced siderophore production also inhibited the growth of important plant pathogens. Overall, our work suggests that not only the iron availability but also the nitrogen fertilizer sources could significantly impact the competition for iron between crop-colonizing microorganisms.

Optimum Utilization of Different Nitrogen Fertilizer Sources for Improving Soil Properties and Agro-Physiological Indices of Maize Crop under Humid Subtropical Conditions of Pakistan

Optimum Utilization of Different Nitrogen Fertilizer Sources for Improving Soil Properties and Agro-Physiological Indices of Maize Crop under Humid Subtropical Conditions of Pakistan

Effect of spacing, source of nitrogen fertilizer and sodium nitro Prusside on growth and yield of African marigold (Tagetes erecta L.) during summer in Andhra Pradesh

Effect of spacing, source of nitrogen fertilizer and sodium nitro Prusside on growth and yield of African marigold (Tagetes erecta L.) during summer in Andhra Pradesh

Effects of Different Sources of Nitrogen Fertilizer On the Yield and Fruit Quality of Persian Lime Under Nubaria Conditions

Effects of Different Sources of Nitrogen Fertilizer On the Yield and Fruit Quality of Persian Lime Under Nubaria Conditions

Efficacy of fertilizer nitrogen source, stabilizer, and application timing for corn nitrogen nutrition

AbstractEnhancing fertilizer nitrogen use efficiency (NUE) in corn (Zea mays L.) production is critical for closing yield gaps, increasing producer profitability, and promoting environmental stewardship. In 2014 and 2015, a field experiment was conducted to determine the potential for fertilizer N stabilizer products to improve NUE of granular urea and urea ammonium nitrate (UAN) solution applied to strip‐till corn. A urease inhibitor (UI) or nitrification inhibitor (NI) or both were added at labeled rates to urea or UAN solution for a target rate of 180 kg N ha−1. At V3, a single application of broadcast granular urea and subsurface banded UAN solution with and without fertilizer N stabilizers was made. A split application (50% at V3; 50% at V6) of subsurface banded UAN solution served as a control representing a standard grower practice. Fertilizer N stabilizers improved components of NUE, such as grain N recovery efficiency (GNRE) and partial factor productivity (PFP). A single full rate UAN application did not differ in terms of grain yield each year but did result in less PFP and GNRE in 2015 as compared to the grower standard practice. A timely one‐time full season N rate subsurface banded application of UAN treated with UI and NI to improve NUE could be a viable substitute for the practice of multiple fertilizations. Untreated broadcast urea was inferior to UAN as a N source for corn, but when treated with both a UI and NI, NUE was improved.

Interactive effects of soil salinity and nitrogen fertilizer types on nitrous oxide and ammonia fluxes

Soil salinization, impaired by climate change and poor management practices, poses a global threat, particularly in arid and semi-arid regions, leading to significant land degradation. This study aims to investigate the effects of different nitrogen (N) fertilizer sources (urea, ammonium-sulfate, and biogas waste) on CO2, N2O, and NH3 emissions and soil enzyme activities in two soil types varying in salinity level (non-saline: EC = 1.15 dS m−1, and saline: EC = 35.80 dS m−1) in a robotized continuous-flow soil incubation system. Our results showed a sharp increase in N2O and CO2 emissions (up to 0.51 ± 0.02 g N2O-N ha−1 day−1, 28.1 ± 3.9 kg CO2-C ha−1 day−1) in non-saline soils following soil rewetting, attributed to bacterial denitrification. However, this pattern was not observed in saline soils, suggesting that salinity causes partial inhibition to the regeneration of soil organic matter mineralization and denitrification processes after rewetting. Although salinity did not alter the overall cumulative N2O losses in any fertilizer treatment, it significantly delayed the evolution of N2O peak during the incubation period. On the other hand, NH3 volatilization was significantly higher in N-fertilized saline soils compared to non-saline soils (241% and 157% in ammonium-sulfate and biogas waste treatments, respectively), except for urea treatment, likely due to the decrease in nitrification rates. Furthermore, the study clearly showed lower soil enzyme activity levels for both nitrate reductase and urease activity. Interestingly, the lowest NH3 emissions were measured in urea treatment in both soils. Overall, our findings highlight the complex interplay between soil salinity, nitrogen fertilizer sources, and microbial processes, significantly influencing gaseous nitrogen emissions and N cycling in agricultural soils. Identifying the specific fertilizer treatments that minimize or maximize gaseous nitrogen losses in varying soil salinity, may guide the selection of appropriate fertilization strategies for farmers and policymakers to mitigate environmental impacts of fertilizer use during agricultural production.

Effects of Rainfall Intensity and Slope on Infiltration Rate, Soil Losses, Runoff and Nitrogen Leaching from Different Nitrogen Sources with a Rainfall Simulator

The combined effects of slope gradient, rainfall intensity, and nitrogen fertilizer source on infiltration, runoff, soil loss, and nitrogen (N) leaching in agricultural areas are not thoroughly understood, despite their critical importance in sustainable agriculture. Previous studies have focused on these factors individually, leaving a significant gap in knowledge regarding their synergistic impact. Investigating the interplay between slope gradients, rainfall intensities, and N fertilizer sources is vital to developing effective soil and water conservation strategies and implementing sustainable agricultural practices. This study is comprised of two experiments. Experiment 1 was designed as a 3 × 2 × 3 factorial arrangement, incorporating three levels of rainfall intensity (RI) (45, 70, and 100 mm/h), two slope gradients (5 and 8°), and three soil types (sandy loam, silt loam, and clay loam), aimed at assessing runoff, infiltration, and soil loss. Experiment 2, laid out as 3 × 2 × 3 × 3 factorial, expanded on this, adding N fertilizer source (urea, CaCN2, and limestone ammonium nitrate (LAN) at 130 kg/ha N) and assessing N leaching alongside the previous metrics. Both experiments used a rotating disc rainfall simulator and were replicated four times. Results revealed that steeper slopes (8°) led to increased runoff and soil loss, impeding infiltration, while gentler slopes (5°) facilitated greater infiltration and minimized soil loss. Rainfall intensity played a significant role, with 70 mm/h/5° combinations promoting higher infiltration rates (48.14 mm/h) and 100 mm/h/8° resulting in lower rates (37.07 mm/h for sandy loam and silt loam, 26.09 mm/h for clay loam). Nitrogen leaching varied based on N source; urea at 130 kg/ha N led to higher losses (7.2% in sandy loam, 6.9% in silt loam, 6.5% in clay loam), followed by LAN (6.9% in sandy loam, 6.7% in silt loam, 6.3% in clay loam) while CaCN2 at the same rate resulted in lower N losses (6.4% in sandy soil, 4.4% in silt loam, 4.2% in clay soil). This research highlights the critical need to consider both slope gradient and rainfall intensity in conjunction with appropriate nitrogen fertilizer sources when developing strategies to mitigate soil erosion and nutrient loss in agricultural settings.

Effect of Different Sources of Nitrogen and Bio Fertilizers on Growth, Yield and Quality of Cherry Tomato [Solanum lycopersicum L.) Var. Cerasiforme] in Polyhouse Conditions

The present investigation was carried out at Research Farm, Department of Horticulture, Naini Agricultural Institute, SHUATS, Naini, Prayagraj, Uttar Pradesh during the Kharif-2022 with a view to identify the effect of different sources of nitrogen and bio fertilizers on growth, yield and quality of cherry tomato” [Solanum lycopersicum L.) var. cerasiforme] in polyhouse conditions. The experiment was laid in Randomized block design (RBD) with 9 treatments and 3 replications with different combination in RDF and application of organic nutrition. Under this experiment, overall, 10 treatment were taken. From the above experimental finding it may be concluded that the treatment T9 (75% N through urea + 25% N through FYM + Azotobacter (4 kg ha-1) + PSB (4 Kg ha-1) was found to be best in the terms of growth parameters like highest plant height (283.35 cm) at 120 DAT, maximum number of branches per plant (72.33 branches) at 120 DAT. In terms of earliness, it was found to have minimum days to attain 50% flowering (55.93 DAT). In terms of yield T9 had highest number of fruits per cluster (5.57 fruits), and fruit yield per hectare (25.88 t ha-1).

Nitrogen Use Efficiency and Yield Levels Using Soluble and Controlled-release Urea Formulations in Tomato Production

This research study evaluated the suitability of controlled-release urea (CRU) as an alternate nitrogen (N) fertilizer source to conventional soluble urea (U) for tomato production under a humid, warm climate in coastal plain soils. Tomatoes are typically produced on raised plastic-mulched beds, where U is fertigated through multiple applications. On the other hand, CRU is applied once at planting, incorporated into soil before the raised beds are covered with plastic mulch. N source and management will likely impact tomato yield, N use efficiency (NUE), and apparent recovery of N fertilizer (APR). A 2-year field study was conducted on fall and spring tomato crops in north Florida to determine the crop N requirement and NUE in tomatoes (var. HM 1823) grown in sandy soils under a plastic-mulched bed system. In addition to a no N fertilizer treatment, three urea N sources [one soluble source and two polymer-coated CRU sources with different N release durations of 60 (CRU-60) and 75 (CRU-75) days] were applied at three N rates (140, 168, and 224 kg⋅ha−1). Across all N sources and N rates, fall yields were at least 20% higher than spring seasons. At the 140 kg⋅ha−1 N rate, APR and NUE were improved, especially when U was applied in fall tomato, whereas preplant CRUs improved N efficiency in spring tomato. Based on the lower APR values found in spring production seasons (0% to 16%) when compared with fall (57.1% to 72.6%), it can be concluded that residual soil N was an important source for tomatoes. In addition, the mean whole-plant N accumulation of tomato was 102.5 kg⋅ha−1, further indicating that reducing the N rate closer to crop N demand would greatly improve conventional vegetable production systems on sandy soils in north Florida. In conclusion, polymer-coated CRU and fertigation U applications were able to supply the N requirement of spring and fall tomato at a 38% reduction of the recommended N rate for tomato in Florida (224 kg⋅ha−1). Preliminary results show that adoption of CRU fertilizers can be considered a low-risk alternative N source for tomato production and the ease of applying CRU once during the bed preparation period for tomato may be an additional incentive.

Post-anthesis dry matter and nitrogen accumulation, partitioning, and translocation in maize under different nitrate-ammonium ratios in Northwestern China.

An appropriate supply of ammonium (NH4+) in addition to nitrate (NO3-) can greatly improve plant growth and promote maize productivity. However, knowledge gaps exist regarding the mechanisms by which different nitrogen (N) fertilizer sources affect the enzymatic activity of nitrogen metabolism and non-structural carbohydrates during the post-anthesis period. A field experiment across 3-year was carried out to explore the effects of four nitrateammonium ratio (NO3-/NH4+ = 1:0 (N1), 1:1 (N2), 1:3 (N3), and 3:1 (N4)) on postanthesis dry matter (DM) and N accumulation, partitioning, transportation, and grain yield in maize. NO3-/NH4+ ratio with 3:1 improved the enzymatic activity of N metabolism and non-structural carbohydrate accumulation, which strongly promoted the transfer of DM and N in vegetative organs to reproductive organs and improved the pre-anthesis DM and nitrogen translocation efficiency. The enzymatic activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamine oxoglutarate aminotransferase, and non-structural carbohydrate accumulation under N4 treatment were increased by 9.30%-32.82%, 13.19%-37.94%, 4.11%-16.00%, 11.19%-30.82%, and 14.89%-31.71% compared with the other treatments. Mixed NO3--N and NH4+-N increased the total DM accumulation at the anthesis and maturity stages, simultaneously decreasing the DM partitioning of stem, increasing total DM, DM translocation efficiency (DMtE), and contribution of pre-anthesis assimilates to the grain (CAPG) in 2015 and 2017, promoting the transfer of DM from stem to grain. Furthermore, the grain yield increased by 3.31%-9.94% (2015), 68.6%-26.30% (2016), and 8.292%-36.08% (2017) under the N4 treatment compared to the N1, N2, and N3 treatments. The study showed that a NO3-/NH4+ ratio of 3:1 is recommended for high-yield and sustainable maize management strategies in Northwestern China.

Soil Properties and Yield of Peppermint (Mentha Piperita L.) in Response to Different Nitrogen Fertilizers Under Water-Deficit Conditions

ABSTRACT Drought and lack of nutrients (including nitrogen) limit crop production in arid and semi-arid regions, including Iran. In order to investigate the combined effect of nitrogen fertilizer sources (organic and chemical) under low water stress on soil properties, biological yield and peppermint essential oil, a three-year experiment was conducted during the spring and summer of the years (2017–2019) in the semi-arid region of Iran. The experiment was conducted as split plots in the form of randomized complete blocks with three replications. Experimental treatments include three irrigation regimes (irrigation after draining 25, 40 and 55% of usable water in the root zone) as the main factor and six fertilizer treatments based on plant nitrogen requirements (100% Chemical, No fertilizer, 50% Chemical + 50% Azocompost, 100% Vermicompost, 100% Azocompost, 50% Chemical + 50% Vermicompost) as sub-factors. The results showed that water-deficit conditions decreased organic carbon, total nitrogen content, soil phosphorus and potassium and biological yield and increased the percentage of peppermint essential oil. Also, in most of the treatment compositions of irrigation regime, the application of organic fertilizer (especially pure vermicompost and azocompost treatments) or combination with chemical fertilizer the increase organic carbon, macronutrients (nitrogen and phosphorus) and micro (iron and zinc) in soil solution, causing improved biological yield and essential oil content and moderated the effects of water-deficit stress on peppermint. These practical measures can help save water and fertilizer consumption while promoting the production of healthy medicinal products over the course of three years.

Enhanced performance of oxygen vacancy-rich In-TiO2 materials for electrocatalytic urea synthesis via a relay catalysis strategy

As an essential source of nitrogen fertilizer for agricultural production and an important raw material in the chemical industry, urea is of great importance to the sustainable development of our economy and society. Oxygen vacancy-rich In3+-doped TiO2, denoted as Vo-In-TiO2, exhibits high catalytic activity for the co-activated reduction of NO3− and CO2 to synthesize urea, with respectively Faraday efficiency (FE) and urea yield (Rurea) of 9.06 % and 759.8 μg mg−1h−1 at an applied potential of −0.65 V versus reversible hydrogen electrode (vs. RHE), which can be attributed to the respective efficacy of oxygen vacancies (Vo) and In3+ and their synergistic effect through relay catalysis. Both experimental and theoretical investigations show that the doped In3+ endows the catalyst with a strong ability to capture CO2, while the Vo acts directly as active site to effectively facilitate the adsorption of *NO3 and further conversion of *NO2, and shows high activity for the NO3− reduction reaction (NO3−RR). That is, Vo reduces NO3− to *NH2, and In3+ plays a role in inducing the direct combination of *NH2 and *CO2 adsorbed on the surface of the catalyst to form the key intermediate *CO2NH2 and thus urea. This strategy of relay catalysis can make full use of the advantages of different parts of the catalyst to achieve a synergistic effect, providing a new approach to the design of highly efficient catalysts.

Coriander response to nitrogen fertilizer sources in different competing levels of weeds

The competition of weeds with crops and nutrient management has a significant effect on the yield and economic efficiency of a country. This study aimed to evaluate the impacts of sulfur-coated urea and common urea on the yield and fatty acid composition of three coriander genotypes (Nahavandi, Pishgam, Ethiopia) under weeded and unweeded conditions. Traits including 1000 seeds weight, fruit yield, content of oil, and composition of fatty acids were examined. Nitrogen fertilizer and weeding treatments significantly improved the weight of 1000 seeds and weeds decreased the yield of fruit. The highest fruit yield was obtained by the Ethiopia genotype in weed-free conditions. Results showed that N fertilizer increased the oil percentage of coriander fruit. Urea fertilizer resulted in the highest oil content in the Nahavandi and Pishgam genotypes under weeded plots in the first and second years, respectively. Also, petroselinic, linoleic, and palmitic acids were the major coriander fatty acid composition. Nahavandi genotype showed the highest palmitic acid. Also, urea in the weed condition led to increase the linoleic acid content in the Nahavandi genotype. Overall, results showed that N fertilizer, especially urea, improved the quality characteristics of coriander fruits.

Nitrogen fertilizer source, rate, placement, and application timing effect on sorghum (grain and forage) and corn grain yields

AbstractIdentifying the limiting nutrient, fertilizer source, rate, placement, additives, and timing of application are critical components of fertilizer management. The objective of this study was to quantify the impact of nitrogen (N) fertilizer source, rate, placement method, additives, application timing, and environment on yields of grain sorghum, forage sorghum [Sorghum bicolor (L.) Moench], and corn (for grain, Zea mays L.). Independent field experiments were conducted at 13 different environments in Kansas from 2008 through 2013 on grain sorghum, forage sorghum, and corn. Treatments were an incomplete factorial combination of four fertilizer placement methods, three fertilizer types, five fertilizer additives, three fertilizer application times, and six fertilizer rates that varied by location and across years. Results showed grain and forage sorghum yields responded to N fertilizer in environments that were not extremely dry (<136 mm) or wet (>651 mm). Corn responded to N fertilizer application only in high‐precipitation environments. For grain sorghum, where rate × placement × source × additive interaction was significant, broadcast application of urea (source) at high rates (67–134 kg N ha−1), with summer application timing, or with additive in winter (with environmentally smart nitrogen [ESN]) resulted in up to 43% greater yield compared with application of urea‐ammonium nitrate (UAN; source) and surface band (placement) at 67 kg ha−1 without additives. In the one site‐year where forage sorghum responded to fertilizer application, forage yields with preplant application of UAN at 56–140 kg ha−1 were 164% greater than the control. For corn, application of either urea or UAN fertilizer, UAN in coulter or surface band, with ESN blend, applied at planting, and at highest rates (160 kg ha−1) resulted in best yields compared with the alternatives and 110% greater yield compared with the unfertilized control. We concluded that fertilizer rate is an important management component as it consistently affected yield regardless of crop considered. Fertilizer placement and timing have crop‐specific importance as they were significant for only corn, but the main effect of additives (N stabilizers) was not significant for any of the crops. Environment and crop type influenced crop response to N fertilizer rate, timing, placement, and additives.

A novel method for production of nitrogen fertilizer with low energy consumption by efficiently adsorbing and separating waste ammonia

Recovering waste NH3 to be used as a source of nitrogen fertilizer or liquid fuel has recently attracted much attention. Current methods mainly utilize activated carbon or metal-organic frameworks to capture NH3, but are limited due to low NH3 adsorption capacity and high cost, respectively. In this study, novel porous materials that are low cost and easy to synthesize were prepared as NH3 adsorbents by precipitation polymerization with acid optimization. The results showed that adsorption sites (‒COOH, –OH, and lactone) which form chemical adsorption or hydrogen bonds with NH3 were successfully regulated by response surface methods. Correspondingly, the dynamic NH3 adsorption capacity increased from 5.45 mg g−1 to 129 mg g−1, which is higher than most known activated carbon and metal-organic frameworks. Separation performance tests showed that NH3 could also be separated from CO2 and CH4. The findings in this study will advance the industrialization of NH3 polymer adsorbents and provide technical support for the recycling of waste NH3.

Estrutura do dossel, aspectos comportamentais e fisiológicos de ovinos terminados em pasto, usando-se torta de mamona como insumo alternativo

ABSTRACT The purpose was to evaluate structural characteristics of pasture, behavioral aspects and physiological parameters of sheep finished on irrigated Tamani grass pasture under continuous stocking, using castor bean cake as alternative input. Structural characteristics of the pasture were assessed in a randomized block design in 2 x 2 factorial arrangement, with two sources of nitrogen fertilization (mineral - urea and organic - in natura castor bean cake) and two supplements (with or without detoxified castor bean cake), in four replications (paddocks). Behavioral aspects and physiological parameters were assessed in a randomized block design with four treatments, and repeated measures over time in eight replications (sheep). Total forage biomass, green leaf blade biomass, grazing, rumination, and idleness times, as well as respiratory rate and rectal temperature were assessed. Urea provided greater leaf blade biomass (1,807 kg DM.ha.cycle-1) and tiller population density (1,592 tillers.m-2). Grazing time reduced 65 minutes.day-1 for animals supplemented with detoxified castor bean cake and kept in pastures fertilized with urea. The use of castor bean cake did not change the physiological parameters of the animals in any of the managements evaluated and can be used as a strategic input in the finishing of sheep on pasture.

Grain yield, cooking quality, and aroma of fragrant rice as affected by nitrogen source and method of application

<p>One constraint is the incapacity of existing agronomic studies on rice yield, aroma, and cooking quality to fully assess the effects of various applications and sources of nitrogen (N) fertilizer. It is challenging for us to understand how different N inputs impact rice's sensory and cooking qualities in addition to crop productivity because of this research gap. So, a two-year pot experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka, under an open field plastic net house from July 15 to December 4 in 2020 and 2021. The study used Bangladesh Rice Research Institute (BRRI) dhan70 as the test crop. The experiment examined two factors: the methods and source of N application. Three methods of N application were tested: 100% soil application (NM<sub>1</sub>), 2% foliar spray at tillering and booting stages (NM<sub>2</sub>), and a combination of 50% soil application and 2% foliar spray at the booting stage (NM<sub>3</sub>). Three sources of N were also evaluated: Urea (NS<sub>1</sub>), ammonium nitrate (NS<sub>2</sub>), and ammonium sulfate (NS<sub>3</sub>). Total 41.0 kg N ha<sup>−1</sup> was applied considering the nitrogen content in Urea (46%), ammonium nitrate (35%), and ammonium sulfate (21%). The experiment followed a randomized complete block design (RCBD) with three replications. The results indicated that the application of N significantly influenced most of the studied parameters. The combined application of N as a foliar dose and soil application, along with ammonium nitrate and ammonium sulfate, showed improved results for various parameters such as gelatinization temperature, gel consistency, protein content, cooking time, imbibition ratio, 2-AP content, grain aroma, and taste of BRRI dhan70 compared to 100% soil application of N. The highest grain yield and 2-AP was observed in the NM<sub>3</sub>NS<sub>3</sub> treatment (35.437 g·pot<sup>−1</sup> and 0.137 µg·g<sup>−1</sup>, respectively) which was statistical similar with NM<sub>3</sub>NS<sub>2</sub> treatment while the lowest yield and 2-AP was recorded in NM<sub>1</sub>NS<sub>1</sub> (24.877 g·pot<sup>−1</sup> and 0.076 µg·g<sup>−1</sup>, respectively).</p>

Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (Allium cepa) Bulbs

Onion (Allium cepa) is one of the world’s most consumed, nutrient-dense foods, low in calories and containing a rich amount of major bioactive compounds, vitamins, and minerals. The purpose of this study was to determine the influence of different nitrogen (N) fertilizer sources on the nutritional and phytochemical qualities of short-day onions. A white-type onion (cv. Texas Grano) was subjected to different fertilizer application treatments, namely (i) pre-plant base application of 80 kg ha−1 N from CaCN2, alone or in combination with (ii) top-dressing with 50 kg ha−1 N from limestone ammonium nitrate (LAN), or (iii) top-dressing with 50 kg ha−1 N from urea, (iv) pre-plant base application of 80 kg ha−1 N from LAN and top-dressing with 50 kg ha−1 N from LAN, (v) pre-plant base application of 80 kg ha−1 N from urea and top-dressing with 50 kg ha−1 N from urea, and (vi) 0 kg ha−1 N. Pre-plant application of CaCN2 (80 kg ha−1 N) outperformed standard onion fertilizers, urea (130 kg ha−1 N) and LAN (130 kg ha−1 N), significantly enhancing total phenolic content, antioxidant activity, and calcium (Ca) and potassium (K) content in onion bulbs. Applying 50 kg ha−1 N from urea as top-dressing with the pre-plant application of CaCN2 (80 kg ha−1 N) elevated total phenolics (5.48 mg GAE g−1) and flavonoids (0.741 mg CE g−1) in the onion bulbs. The highest antioxidant activity (55.9%) and free radical scavenging activity (26.3%) were achieved with top-dressing 50 kg ha−1 N from LAN following CaCN2 pre-plant application. Application of CaCN2 + urea also significantly increased onion bulb potassium (2335 mg kg−1) and calcium (828 mg kg−1) contents, while CaCN2 combined with LAN improved magnesium (123.3 mg kg−1) content. This study recommends pre-plant CaCN2, top-dressed with either LAN or urea, for improved phytochemical components, antioxidant activities, and certain mineral content in onion bulbs. These findings present a practical approach for cultivating nutrient-rich and phytochemically abundant onion bulbs, promoting improved human health.

Evaluation of nano-nitrogen fertilizers and other nitrogen sources on the performance of Guinea grass plants grown in newly reclaimed soil under water deficiency

Water deficiency and chemical fertilizers' pollution are two of many factors causing imbalance in the ecosystem rhythm, which reflects on farm livestock quality and quantity, particularly in arid and semi-arid regions. Limited research is available on the use of different sources of nitrogen fertilizers on pasture crops; hence, an open field research experiment was carried out in newly reclaimed soil to investigate the effect of different sources of nitrogen fertilizers on maximizing protein level and production of Guinea grass (Panicum maximum Jacq.) plant under water deficiency. Present data from two successive seasons revealed that: plants received nitrogen in the form of nano particles recorded significant increases in yield, morphological parameters, leaf anatomy, and chemical composition (macro and micro nutrients, total carbohydrates, plant pigments and crude protein) over control (plants that received the recommended dose of NPK fertilizers) in both growing seasons. In addition, endogenous hormones; gibberellins (GA3) and abscisic acid (ABA) beside enzymes; superoxide dismutase (SOD) and peroxidase (POD) had been affected by different treatments. The lowest amounts of cellulose, hemicellulose and lignin were resulted from nitrogen nano particles treatment, while the rates of leaf photosynthesis, stomatal conductance, intercellular CO2 concentration, and water use efficiency were enhanced also by nitrogen nano particles treatment application. The present findings suggested that increasing crude protein level of Guinea grass plant grown in newly reclaimed soil by addition of the mentioned nanoparticles could be a promising approach to improve crop productivity under water deficiency and reduce environmental pollution.