Nitrogen Application Research Articles

IMPACT OF VARIED AMOUNTS OF NITROGENOUS FERTILIZERS ON GRAIN YIELD AND RELATED AGRO-PHYSIOLOGICAL TRAITS IN SPRING WHEAT (TRITICUM AESTIVUM L.)

The application of nitrogen (N) is a critical factor influencing grain yield and agro-physiological traits in spring wheat (Triticum aestivum L.). This study aimed to evaluate the impact of varied nitrogen levels on grain yield and associated traits under field conditions. The study was conducted in Chak No. 136 / 6.R Haroonabad, District Bahawalnagar under the supervision of the Institute of Soil Fertility (Field) during the crop year 2022-23. A randomized complete block design (RCBD) was used, with five N treatments (160, 145, 131, 117 and 103 kg ha⁻¹) applied across three replicates. Key parameters, including flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield, were measured. The results showed a significant increase in flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield with increasing nitrogen application, with the highest yield observed at 160 kg ha⁻¹. The results unveiled the presence of highly significant variations among nitrogen treatments in wheat variety based on the agro-physiological parameters including flag leaf area, thousand-grain weight, number of spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield. Furthermore, the results also unveiled that treatments with higher nitrogen dosage produce better results for almost all the study parameters including grain yield. The correlation coefficient analysis also confirmed the results and suggested that any wheat breeding program aimed at improving wheat yield must select its parental genotypes based on traits having the highest correlation with yield i.e., flag leaf area, thousand-grain weight, number of grains per spike, chlorophyll a, stomatal conductance and net photosynthetic rate except the number of spikelets per spike and biological yield for which the correlation was positive but non-significant. The results suggest that nitrogen in higher amounts up to a certain level is necessary for obtaining maximum output from wheat crops under semi-arid conditions.

Analysis of organic matter stock dynamics in arable soils of Yamal: simulation experiments with the ROMUL model

The goal of this work is to analyze the dynamics of soil organic matter (SOM) in arable soils of Yamal using computational experiments with the ROMUL model. Soil temperature and moisture dynamics were simulated using the SCLISS model. The Yamal experimental station was organized in 1932. The soil is Plaggic Podzol. The thickness of humus horizon (PY) is 30 cm. Pools, kg/m2: SOM – 9.32 and 13.75; N – 0.46 and 0.66 for 0–20 and 0–30 cm respectively. Background: soddy-green-moss tundra near Salekhard. Soil: Folic Podzol: litter (O, 2 cm) and humus-accumulative (AY, 4 cm) and illuvial ferruginous (BF, 6 cm) horizons. Pools, kg/m2: SOM – 1.38 and 2.69, N – 0.03 and 0.18 for 0–2 and 2–6 cm respectively. The quantity and quality of background fall was estimated according to literature data. Clarification of the amount of fall was carried out by the method of inverse problem solving (spin-up). Peat application was simulated: starting application in the dose of 12 kg/m2 and maintenance (every 6 years) in doses 4, 8 and 12 kg/m2, N 1%. Application of mineral fertilizers, 2 variants: a) N 4 g/m2 (40 kg/ha) in peatting years and b) application of the same dose of nitrogen every year. The duration of computational experiments is 30 and 90 years. Computational experiments showed that after the starting peatting of Folic Podzol at the rate of 12 kg/m2 after 30 years, only 15% of the applied detritus remained. Maintenance peatting of 8–12 kg/m2 leads to an increase in SOM pool to 20–30 kg/m2 and excessive accumulation of detritus. Application of 4 kg/m2 of peat once every 6 years for 90 years shows the dynamics of SOM pools from Folic Podzol to Plaggic Podzol which is confirmed by field survey data. Application of mineral nitrogen (4 g/m2) once every 6 years does not affect SOM pools. Annual application of mineral N (4 g/m2) increases SOM pools due to intensified humification. This fact requires experimental verification.

Effects of foliar silicon and nitrogen applications on winter color retention and spring green-up of zoysia grass

Zoysia japonica Steud. (zoysia grass), with its high drought, shade, and salt tolerance, it is an excellent choice for green areas. However, in regions with subtropical climates, it goes into winter dormancy with a loss of green color and functionality, which is a main barrier to its widespread use. The application of silicon and nitrogen in fall was hypothesized to enhance winter color retention of Z. japonica. This study assessed the impact of fall (late-season) nitrogen (0, 2.5, or 5.0 g/m2 ammonium sulfate) and foliar silicon (0, 3, or 6 mL/L potassium silicate) applications on the winter color retention of Z. japonica grown in the field. The experiment was conducted over two consecutive growing seasons in Antalya, Türkiye. Turfgrass quality, color, chlorophyll content, shoot density, and winter dormancy were all improved by late-season nitrogen application. Overall, two sequential nitrogen applications at 5 g/m2 in fall provided 65% to 100% green coverage with acceptable turfgrass quality during fall and winter, indicating the possibility of maintaining the year-round green color of Z. japonica in subtropical climates. However, the silicon treatment did not affect the winter color retention of Z. japonica. The apparent lack of a beneficial response of Z. japonica to the silicon application might be due to the dose, application methods, and silicon source.

Effect of Water and Nitrogen Coupling Regulation on the Growth, Physiology, Yield, and Quality Attributes of Isatis tinctoria L. in the Oasis Irrigation Area of the Hexi Corridor

To address the prevailing problems of high water and fertilizer input and low productivity in Isatis tinctoria L. production in the Hexi Corridor in China, the effects of different irrigation amounts and nitrogen application rates on growth characteristics, photosynthetic physiology, root yield, and quality of I. tinctoria plants were studied with the aim of obtaining the optimal irrigation level and nitrogen application rate. From 2021 to 2023, we established a two-factor split-plot experiment in the oasis irrigation area with three irrigation amounts (sufficient water, medium water, and low water are 100%, 85%, and 70% of the typical local irrigation quota) for the main zone; three nitrogen application rates (low nitrogen, 150 kg ha−1, medium nitrogen, 200 kg ha−1, and high nitrogen, 250 kg ha−1) for the secondary zone; and three irrigation amounts without nitrogen as the control to explore the response of these different water and nitrogen management patterns for I. tinctoria in terms of growth characteristics, photosynthetic physiology, root yield, and quality. The results showed the following: (1) When the irrigation amount was increased from 75% to 100% of the local typical irrigation quota and the nitrogen application rate was increased from 150 to 250 kg ha−1, while the plant’s height, leaf area index, dry matter accumulation in the stem, leaf, and root, as well as the net photosynthetic rate (Pn), the stomatal conductance (Gs), and the transpiration rate (Tr) of I. tinctoria increased gradually, and the root–shoot ratio decreased. (2) When the irrigation amount increased from 75% to 100% of the local typical irrigation quota, the yield and net proceeds of I. tinctoria increased from 43.12% to 53.43% and 55.07% to 71.61%, respectively. However, when the irrigation quota was 100% of the local typical irrigation quota, and the nitrogen application rate increased from 150 to 200 kg ha−1, the yield of I. tinctoria increased from 21.58% to 23.69%, whereas the increase in nitrogen application rate from 200 to 250 kg ha−1 resulted in a decrease in the yield of I. tinctoria from 10.66% to 18.92%. During the 3-year experiment, the maximum yield of I. tinctoria appeared when treated with sufficient water and medium nitrogen, reaching 9054.68, 8066.79, and 8806.15 kg ha−1, respectively. (3) The effect of different water and nitrogen combination treatments on the root quality of I. tinctoria was significant. Under the same irrigation level, increasing the nitrogen application rate from 150 to 250 kg ha−1 could increase the contents of indigo, indirubin, (R,S)–goitrin, total nucleoside, uridine, and adenosine in the root of I. tinctoria from 3.94% to 9.59%, 1.74% to 12.58%, 5.45% to 18.35%, 5.61% to 11.59%, 7.34% to 11.32%, and 14.98% to 54.40%, respectively, while the root quality of I. tinctoria showed a trend of first increasing and then decreasing under the same nitrogen application level. (4) AHP, the entropy weight method, and the TOPSIS method were used for a comprehensive evaluation of multiple indexes of water–nitrogen coupling planting patterns for I. tinctoria, which resulted in the optimal evaluation of the W3N2 combination. Therefore, the irrigation level was 100% of the local typical irrigation quota, the nitrogen application rate should be appropriately reduced, and controlling the nitrogen application rate at the level of 190.30–218.27 kg ha−1 can improve water–nitrogen productivity yields for I. tinctoria and root quality. The results of this study can provide a theoretical basis and technical support for a more reasonable water and fertilizer management model for the I. tinctoria production industry in the Hexi Corridor in China.

Nitrogen Fertilization Using Conventional and Slow-Release Fertilizers at Multiple Levels in Lolium multiflorum Lam. Pastures

Pastures are essential for sustaining dairy production, particularly in temperate climates where year-round grazing is feasible. However, comprehensive analyses of their productivity, efficiency, and cost evaluation remain uncommon. This study evaluated the productivity, quality, nitrogen fertilization use efficiency, and production costs of Lolium multiflorum Lam pasture on a farm in São Miguel Island. The research compared conventional nitrogen fertilizer with slow-release nitrogen fertilizer at application rates of 320 and 160 kg N ha−1, alongside a control treatment. A Latin square design with five treatments was employed to assess both agronomic and economic performance. The results showed that the type of fertilizer did not significantly influence productivity or quality, while nitrogen levels had a notable impact. Higher nitrogen doses increased dry matter yield and crude protein content. Fiber characteristics remained relatively stable, though neutral detergent fiber and acid detergent fiber levels tended to rise with increased nitrogen application. Nitrogen fertilizer use efficiency consistently exceeded 70%, regardless of the fertilizer type or application rate. Regarding production costs, conventional fertilizer was significantly more cost-effective than slow-release fertilizer, underscoring the importance of selecting economically viable options without compromising agronomic performance in forage production.

Effects of water quality and nitrogen on wheat productivity: Experimental and modelling study using the SALTMED model

AbstractThe effects of different water qualities and nitrogen doses need to be investigated for wheat growth to determine the optimal management strategy for sustaining wheat production potential to ensure human food security. Therefore, a 2‐year study (2020–2021 to 2021–2022) was conducted on wheat irrigated with different water qualities, including canal water (Ca), tubewell water (Tu) and mixed Ca‐Tu water (Mx), each fertilized with two nitrogen doses, that is, N75 = 75 kgN.ha−1 and N100 = 100 kgN.ha−1. Ca⨯N100 performed best, with 5.12 t.ha−1 grain yield, 11.60 t.ha−1 biomass, 102.83 cm plant height and 1.32 kg.m−3 water productivity. The best values of the root mean square error (RMSE), normalized root mean square error (NRMSE), coefficient of determination (R2) and coefficient of residual mass (CRM) were 0.11, 0.12, 0.93 and −0.004, respectively, for calibration and 0.13, 0.15, 0.87 and ±0.01, respectively, for validation of the SALTMED model. The scenario simulation was performed for additional levels of water salinity (electrical conductivity [EC] = 8 and 12 dS.m−1) and nitrogen doses (50, 125, 150 and 175 kgN.ha−1). The results revealed improvements in wheat grain yield of 107%, 16% and −6% at EC = 8 dS.m−1 and 125%, 31% and 5% at EC = 12 dS.m−1, while the improvements in biomass were 113%, 22% and −2% at EC = 8 dS.m−1 and 137%, 29% and 8% at EC = 12 dS.m−1 with increasing nitrogen doses from 50–125 kg.ha−1, 125–150 kg.ha−1 and 150–175 kg.ha−1, respectively. It is recommended that high‐quality water with the lowest possible EC and nitrogen applications of up to 150 kgN.ha−1 be adopted for wheat production in semi‐arid areas of Punjab, Pakistan.

Reduced Nitrogen Application with Dense Planting Achieves High Eating Quality and Stable Yield of Rice.

Rational nitrogen (N) application can enhance yield and improve grain eating quality in rice. However, excessive N input can deteriorate grain eating quality and aggravate environmental pollution, while reduced N application (RN) decreases rice yield. Reduced N application with dense planting (RNDP) is recommended for maintaining rice yield and improving N use efficiency. However, the effects of RNDP on the rice grain eating quality and starch structure and properties remain unclear. A two-year field experiment was conducted to investigate the effects of RNDP on the rice yield, grain eating quality, and starch structure and properties. Compared to conventional N treatment, RN decreased significantly the rice yield, while RNDP achieved a comparable grain yield. Both the RN and RNDP treatments improved significantly the rice eating quality. The high eating quality of RNDP was attributed to increased gel consistency, pasting viscosity, and stickiness after cooking as well as decreased protein content. A further analysis of starch structure and properties revealed that RNDP decreased the relative crystallinity, lamellar intensity, gelatinization enthalpy, and retrogradation enthalpy of starch. Therefore, RNDP achieved a stable rice yield and enhanced rice eating quality. These findings provide valuable insights into obtaining optimal quality and consistent yield in rice production under reduced N conditions.

Improving Sorghum (Sorghum bicolor L.) Production through the Use of Azospirillum sp. AZ6 and Trichoderma harzianum T4-Based Biostimulants

Objectives: The objective(s) of the present experiment was to evaluate the effect of Azospirillum sp. AZ6 and Trichoderma harzianum T4-based biostimulants formulated in Mali on the growth and yield of Sorghum in Mali field during monsoon season. Study Design: The experiment was conducted in a completely randomized block design with three treatments. The blocking factor was the direction of rainwater runoff. Methodology: The study was carried out in the rural commune of Ouéléssebougou located in the Sudanian. The sorghum seeds inoculated or non-inoculated with Azozpirillum sp. AZ6, Trichoderma harzianum T4, were randomly sown in single-cropped with no nitrogen (N) application. For the control, 100% dose of N was applied at sowing time at 120 kg/ha. Sorghum plant height, sorghum yield, number of panicles and the weight of 1000 grains weight were evaluated. Results: The salient findings showed a significant increase of the parameters examined by Azospirillum sp. AZ6 and Trichoderma harzianum T4-based biostimulants. Inoculation of AZ6 improved sorghum yield by 68,25%, while T4 by 8.73% in comparison with the control. Conclusion: It is evident that Azospirillum sp. AZ6 and Trichoderma harzianum T4 are suitable for inoculating sorghum (Sorghum bicolore L.). Azospirillum sp. AZ6 produced the highest plant height, yield, number of panicles, and 1000 grain weight relative to Trichoderma harzianum T4 and the non-inoculated control. Therefore, this suggest that Azospirillum sp. AZ6 is suitable for large scale application in sorghum fields to reduce the production costs and increase yield while reducing N fertilizer application rate

Understanding nitrogen allocation dynamics in Indian mustard: Insights from enzyme activity and ideotype analysis

The study explores the effect of varying levels of nitrogen (N) application on N allocation in Indian mustard (Brassica juncea) genotypes from vegetative to the generative phases. The use of a heat map and PCA biplot analysis identifies two distinct sets of ideotypes. The first set is represented by genotype IC212031 having “Stay-green” phenotype with effective N regulating enzymes, high N uptake (NUpt) and better root development. The second set of ideotype is represented by HB9902 having delayed flowering phenology phases. The study highlights the relevance of Nitrate reductase (NR) in the final oil buildup in seeds (r = 0.5, p = 0.09). The considerable rise in NR activity from pre-anthesis to post-anthesis stages translates to higher seed storage compounds such as oil (r=−0.65, p = 0.03). And the developed prediction models confirmed the significance of these stages (pre-anthesis and post-anthesis) in the accumulation of seed storage components with emphasis on oil content. Similarly, this prediction model helps us to study the cause and effect relationship between various factors and oil content. The notable rise in Nitrite reductase (NiR) activity during the post-anthesis phase suggests its role in assimilating N for the storage of seed components, most likely proteins. Further, the inverse relationship between seed N (−0.53,p= 0.09) and oil content (−0.65, p= 0.03) confirmed that at the post anthesis stage the allocation of N towards precursor carbon compounds happens, which in turn forms either proteins or lipids. This becomes a critical factor in determining the final composition of the seed. Irrespective of N treatment and genotype, the N allocation follows the pattern: seed > siliquae husk > stover > root. However, higher N application rates primarily result in increased NUpt, but not necessarily improve utilisation. Overall, the study highlights the roles of root characteristics, N metabolising enzymes, and flowering phenology in enhancing N allocation and seed production in Indian mustard offering valuable insights for breeding strategies to enhance seed yield, oil content and nutrient efficiency in oilseed crops.

Growth, Development, Yield Attributes and Yield of French Bean (Phaseolus vulgaris L.) as Influenced by Doses and Methods of Nitrogen Application

A field experiment was carried out at School of Natural Resource Management, College of Post Graduate Studies in Agricultural Sciences, CAU, Umiam, Meghalaya during summer season 2021 to study the effect of different doses and application methods of nitrogen on the growth, yield and yield attributes of Frenchbean (Phaseolus vulgaris L.). The experiment comprised of four doses of nitrogen viz.,0, 30, 60, 90 kg ha-1 and two methods of its application i.e., full dose as nitrogen as basal application and 2/3 of nitrogen dose as basal and 1/3 of nitrogen dose split application at active branching stage. The experiments consist of a total of 7 treatments laid out in Randomized Block Design with four replications. Growth parameters such as plant height and number of branches per plant in frenchbean showed a significant increase at all the growth stages with increase in nitrogen doses. Maximum plant height (39.35 cm) and number of branches per plant (3.56) were observed with application of 90 kg N ha-1. The grain yield (762.32 kg ha-1) was observed with application of 90 kg N ha-1 whereas, lowest grain yield was observed in control (146.25 kg ha-1). Yield attributes were observed to follow the same trend with highest number of pods per plant as 5.44, number of seeds per pod as observed significantly more values of all the above said parameters of growth and yield of frenchbeanin comparison to full dose of nitrogen as basal alone. Therefore, the finding of this experiment suggest that the frenchbean should be grown with 90 kg N ha-1 and 2/3 of this dose should be applied as basal application while remaining 1/3 should be applied as top dressing at active branching stage for better growth and yield of frenchbean.

Effects of sowing date and nitrogen applications on the energy efficiency of facultative wheat (Triticum aestivum L.) in a Pannonian environment

Energy efficiency analysis provides a deeper understanding of non-renewable energy dependent cropping systems. In this study, we examined the crop yield and energy efficiency of facultative rainfed wheat (WW – winter wheat, WS – spring wheat) and mineral nitrogen (N) fertilization (0, 50, 100, 150, and 200 kg N ha−1) in two growing seasons 2019/20 and 2020/21 in Central Europe. WW out performed WS significantly overall (2019/20: +30.3 to +47.9 %; 2020/21: +18.9 to +37.3 %) in terms of energy efficiency indicators. The impact of N fertilization on energy efficiency was minimal, largely due to one dose application of mineral N fertilizer. The highest estimated net-energy output (NEO) was observed at 160.2 kg N ha−1, which may not sustainable for this pedo-climatic region due to potential N emissions risks. Zero N fertilization showed best performance in terms of energy use efficiency (EUE), energy intensity (EI), and energy productivity (EP). The ERG z-score, which combines NEO and EUE into a single bi-dimensional indicator, indicated an optimal N fertilization level of 72.0 kg N ha−1.

Response of Solanum tuberosum L. to drip irrigation and nitrogen application: productivity, nutrition composition, bioactive compounds, antioxidant activity

Sustainable crop cultivation is a crucial goal in modern agriculture, aiming to attain high productivity while conserving natural resources. This requires the implementation of rational cultivation techniques, with proper irrigation and fertilization practices playing a crucial role in ensuring plant well-being and providing natural protection against biotic and abiotic stresses. The health-promoting properties of crops are also significantly influenced by irrigation and fertilization. This study investigated the productivity, nutritional composition, bioactive compounds, and antioxidant capacity of Vineta early potato cultivar tubers under drip irrigation conditions, combined with nitrogen fertilization through fertigation or broadcasting. Two-factor trials included drip irrigation (control or drip) and nitrogen application (broadcast or fertigation). Precise treatments, such as drip irrigation and N-fertigation were found to enhance all productivity traits. Both practices positively impacted tuber nutrient content. The highest levels of total polyphenols and chlorogenic acid were observed in non-irrigated and broadcasted tubers. Drip-irrigated and N-fertigated tubers exhibited high levels of vitamin C and antioxidant activity. In summary, the combination of drip irrigation with appropriate fertilization methods positively influenced potato crops, as evidenced by an increase in productivity and the quality of tubers.

Effect of Leaf Clipping and Nitrogen Split Application on Bridegroom Rice Productivity

Bridegroom rice is one the most important indigenous rice variety predominantly grown in Tamil Nadu, India. Lodging in nature and poor responsive to nitrogenous fertilizers affects the yield of this crop. To minimize crop lodging and to enhance the productivity, a field experiment was carried out during Samba 2023 at Experimental Farm, Department of Agronomy, Annamalai University, Tamil Nadu, India to study the effect of leaf clipping and nitrogen split application on bridegroom rice productivity. The experiment was laid out in Factorial randomized block design (FRBD) with three replications. The treatments consisted of two factors viz., Factor I -leaf clipping (L): L1- No leaf clipping, L2 - leaf clipping on 30 DAT at one third of leaf, L3- leaf clipping on 45 DAT at one third of leaf and Factor II - split application of N (N) : N1- no splits (no NPK), N2 - 4 equal splits (basal, 25, 50, 75 DAT), N3­- 5 equal splits (basal 20, 40, 60,80 DAT ) and N4 - 6 equal splits (basal, 15, 30, 45, 60 ,75 DAT). Among the treatments, leaf clipping on 45 DAT at one third of leaf along with application of nitrogen in 6 equal split registered its superiority compared to others which recorded the higher values for growth attributes viz., plant height (243cm), number of tillers hill-1 (23.42), root length (33.56cm), root volume (45.19 cc) and dry matter production (12592 kg ha-1),yield attributes viz., number of panicles m-2 (407.62) and number of grains panicle-1 (158.34) and test weight (42.34g) and yields of rice (grain - 3950 kg ha-1­and straw - 6530 kg ha-1­). Thus, it can be concluded that leaf clipping on 45 DAT at one third of leaf along application of nitrogen in 6 equal splits is a viable practice to enhance the growth and yield of bridegroom rice.

Substituting partial chemical nitrogen fertilizers with organic fertilizers maintains grain yield and increases nitrogen use efficiency in maize

IntroductionLong-term application of excessive nitrogen (N) not only leads to low N use efficiency (NUE) but also exacerbates the risk of environmental pollution due to N losses. Substituting partial chemical N with organic fertilizer (SP) is an environmentally friendly and sustainable fertilization practice. However, the appropriate rate of SP in rainfed maize cropping systems in semi-arid regions of China is unknown.MethodsTherefore, we conducted a field experiment between 2021 and 2022 in a semi-arid region of Northern China to investigate the effects of SP on maize growth, carbon and N metabolism (C/NM), and NUE. The following treatments were used in the experiment: no N application (CK), 100% chemical N (SP0, 210 kg N ha–1), and SP substituting 15% (SP1), 30% (SP2), 45% (SP3), and 60% (SP4) of the chemical N. The relationship between these indicators and grain yield (GY) was explored using the Mantel test and structural equation modeling (SEM).Results and discussionThe results found that the SP1 and SP2 treatments improved the assimilates production capacity of the canopy by increasing the leaf area index, total chlorophyll content, and net photosynthetic rate, improving dry matter accumulation (DMA) by 6.2%–10.6%, compared to the SP0 treatment. SP1 and SP2 treatments increased total soluble sugars, starch, free amino acids, and soluble protein contents in ear leaves via increasing the enzymatic reactions related to C/NM in ear leaves during the reproductive growth stage compared with SP0 treatment. The highest plant nitrogen uptake (PNU) and nitrogen recovery efficiency were obtained under the SP2 treatment, and the GY and nitrogen agronomic efficiency were higher than the SP0 treatment by 9.2% and 27.8%. However, SP3 and SP4 treatments reduced DMA and GY by inhibiting C/NM in ear leaves compared to SP0 treatment. Mantel test and SEM results revealed that SP treatments indirectly increased GY and PNU by directly positively regulating C/NM in maize ear leaves. Therefore, in the semi-arid regions, substituting 30% of the chemical N with SP could be considered. This fertilizer regime may avoid GY reduction and improve NUE. This study provides new insights into sustainable cultivation pathways for maize in semi-arid regions.

Trade optimality and micro-nutrient productivity: Assessing the impact of crop trade on nitrogen fertiliser use efficiency

Intensification of agricultural practices has been pivotal in meeting the nutritional demands of a burgeoning global population. However, the widespread application of nitrogen (N) fertilisers has contributed to environmental pollution. In this study, we quantitatively assessed the role of international crop trade in optimising the productivity of micro-nutrients and its implications for N fertiliser use. Using a comprehensive dataset spanning from 1961 to 2019, we analysed the trade flows of seven key micro-nutrients—vitamin C (VC), vitamin B3 (VB3), vitamin B6 (VB6), calcium (Ca), magnesium (Mg), iron (Fe), and zinc (Zn)—embedded in agricultural products. We developed a novel framework to evaluate trade optimality and functionality based on the concentration-weighted productivity of micro-nutrients per kilogram of N fertiliser. Our findings reveal that while international trade has generally contributed to enhancing micro-nutrient productivity per unit of N fertiliser, trade optimality has shown a decreasing trend. High-productivity countries tend to export less relative to their potential, whereas countries with lower productivity import a larger share of crops. This decoupling suggests the need to re-evaluate trade policies to ensure that they align with sustainable agricultural practices and environmental conservation goals. We also identified potential savings in N fertiliser use through optimised trade practices, with estimated savings of 15–45 Tg of N per year. This could mitigate the negative agricultural impact and demonstrates the significant role that trade can play in achieving global sustainability targets. Overall, our research underscores the importance of aligning international crop trade with sustainable N management strategies to enhance micro-nutrient availability, improve environmental outcomes, and contribute to global efforts in achieving the Sustainable Development Goals.

Optimal Irrigation and Fertilization Enhanced Tomato Yield and Water and Nitrogen Productivities by Increasing Rhizosphere Microbial Nitrogen Fixation

Irrigation and nitrogen application rates have significant effects on greenhouse tomato yields, as well as water and nitrogen use efficiencies, but little is known regarding how these rates affect plant–microbiome interactions and how the associated changes might impact tomato yields. In this greenhouse study conducted over two years, the effects of three irrigation levels (moderate deficit with 65–75% water holding capacity threshold, slight deficit with 75–85%, and sufficient irrigation with 85–95%) and four nitrogen application levels (60, 120, 240, and 360 kg ha−1) on tomato growth, yield, water and nitrogen productivities, and rhizosphere microbial diversities and functions were investigated. The results demonstrated that the highest tomato leaf area, dry biomass, yield, and water and nitrogen productivities were obtained under the treatment with sufficient irrigation. With increasing nitrogen application, the tomato leaf area, dry biomass, yield, and water and nitrogen productivities showed a trend of first increasing and then decreasing. Overall, the treatment (N2W3) with sufficient irrigation and 240 kg ha−1 N was associated with the highest tomato growth, yield, and water and nitrogen productivities. Moreover, optimal irrigation and nitrogen application obviously altered the structures of rhizosphere bacterial and fungal communities, particularly recruiting microbiota conferring benefits to tomato growth and nitrogen fixation—namely, Lysobacter and Bradyrhizobium. Ultimately, optimal irrigation and nitrogen application significantly increased the relative abundances of functions related to carbon, sulfur, and nitrogen metabolism, especially nitrogen fixation. In summary, optimal irrigation and fertilization enhanced tomato yield, as well as water and nitrogen productivities by increasing the nitrogen fixation functions of the rhizosphere microbiome. Our results provide significant implications for tomato cultivation in greenhouses, in terms of optimized irrigation and fertilization.

Evaluation of the Effect of Urea and Nanourea on Growth Pattern of Rainfed Bt Cotton (Gossypium hirsutum L.)

A field experiment was conducted to evaluate the effect of different levels of nitrogen through Nanourea and commercial urea with different time of nitrogen application on Bt Cotton (Gossypium hirsutum L.) Fifteen treatment combinations consisting of five different levels of nitrogen through nano urea and commercial urea such as (125% of RDN through nano urea, 100% of through nano urea, 75% RDN through nano urea, 100% RDN through commercial urea and control plot (No nitrogen)) were applied in three split applications of nitrogen at 30,60,90 DAS (40%,40%,20%), 30,60,90,120 DAS (25%,25%,25%,25%), 30,60,90,120 DAS (30%, 30%,20%,20%) were evaluated in split plot design with three replications. The highest absolute growth rates (AGR) for both plant height and dry matter in the context of application of nitrogen through commercial urea were observed during specific growth intervals: 61-90 days after sowing (DAS) for plant height (1.350 cm day-1 plant-1) and 91-120 DAS for dry matter (2.374 g day-1 plant-1). Similarly, when considering split application of nitrogen, the application of nitrogen at 30,60,90 DAS (40%,40%,20%) showed the highest AGR for plant height (1.054 cm day-1 plant-1) during 61-90 DAS and for dry matter (2.158 g day-1 plant-1) during 91-120 DAS. Furthermore, various growth parameters such as CGR, RGR, NAR, and LAI also exhibited their maximum values under both different levels of nitrogen and the mentioned split application of nitrogen.

Organic waste recycling application increases N availability and mitigates N2O emission without crop yield penalty in the North China Plain.

Agricultural organic waste recycling can supply nutrients for crop production and partially replace chemical nitrogen fertilizers, which is beneficial for waste management and environmental protection. Nevertheless, comprehensive evaluation of the effects of different organic materials applications on crop yield and the environment is limited. Therefore, in this study, a comprehensive investigation of the synergistic effects of straw, pig manure, and biogas residue recycling on the wheat (Triticum aestivum L.) and maize (Zea mays L.) systems was carried out in the North China Plain. Field experiments were conducted from 2019 to 2021, comprising five treatments: straw (ST), pig manure (PM), and biogas residue (BR) partially replacing chemical nitrogen fertilizer, sole application of chemical nitrogen fertilizer (CF), and a control with no nitrogen application (WN). The results showed that organic materials significantly increased soil total nitrogen (3.04%-9.10%) and N recovery efficiency (REN; 42.21%-44.99%), but pig manure was more beneficial in increasing crop yields (3.50%), especially wheat yields (8.72%), and REN was significantly higher than that of the other treatments. Organic materials performed differently in wheat and maize seasons, and wheat yield could be improved by organic materials return. Organic materials stimulated N2O emission in wheat season (4.28%-32.20%), while biogas residue inhibited the N2O emission in maize season (47.47%). The negative effect of straw and biogas residue on yield decreased with increasing years of return, and pig manure continued to contribute to yield. In conclusion, pig manure is the optimal alternative that can increase crop yield, soil N content, and REN without stimulating N2O emissions.

Influence of Foliar Application of Nitrogen through Urea and Nano Urea on Morphophysiological and Yield in Foxtail Millet (Setaria italica L.)

A field experiment was conducted at College of Agriculture Nagpur, during Kharif 2023 in randomized blocked design (RBD) with PDKV Yashshree (BFTM-82) variety, at Research Farm of Agricultural Botany Section, College of Agriculture Nagpur, with three replications and eight treatments. The results revealed that the best treatment 25 N kg ha-1 + two spray of nano urea @ 4 ml L-1 (T8) applied at tillering and pre-flowering stage was significantly superior as compared to other treatments which shows the highest value in morpho-physiological viz., Plant height (163.00 cm) at 80 DAS, days to 50% flowering (57.00), days to maturity (87.00), RGR (0.095 g-1 dm-2 day-1 ) at 60-80 DAS and CGR (0.82 g-1 cm-2 day-1) at 60-80 DAS and yield parameters viz., No. of panicle hill-1 (4.90), Panicle length (24.37 cm), No. of spikelet panicle-1 (66.07), Grain yield kg plot-1 (1.30),Grain yield kg ha-1 (1421.78),Harvest index (63.50%) of foxtail millet.

Modified Slow-Release Urea Fertilizers on Yield and Nitrogen Use Efficiency of Wheat Crop (Triticum aestivum L) for Safe and Sustainable Agricultural System

ABSTRACT Safeguarding the agricultural environment from pollution is one of the most critical challenges facing the world in the context of climate change. The loss of nitrogen fertilizers through agricultural runoff or volatilization in the form of nitrate or ammonia emissions is a significant contributor to pollution. This loss also represents an economic waste that may lead to increased prices of agricultural products. Therefore, finding a solution to this problem has become imperative. An experiment was conducted on wheat plants using various rates of urea coated with slow-release materials. The study aimed to assess the impact of these fertilizers on wheat growth and yield, nutrient uptake, and nitrogen utilization efficiency (NUtE). Results demonstrated that urea fertilizers coated with slow-release materials outperformed conventional fertilizers in terms of wheat growth and yield, uptake of nitrogen, phosphorus, and potassium, as well as NUtE. The most favorable outcomes were achieved using urea-formaldehyde, urea-humic, and urea-biochar fertilizers at 100% of the recommended nitrogen application rate. This resulted in economically viable grain production with high fertilizer efficiency. Based on these findings, we recommend applying either urea-formaldehyde or urea-humic at a rate of 107 kg N ha−1 to produce wheat grain and straw with enhanced NUtE. This approach can help reduce environmental pollution caused by nitrogen losses.