Enhancing Nitrogen Use Research Articles

Biopolymer Urea Composite for Enhancing Nitrogen Use Efficiency in Coastal Sandy Soils of Kerala, India

Aim: To formulate biopolymer urea composites in pellet form and to test their efficacy on the release and leaching of nitrogen in northern coastal sandy soils of Kerala. Place and Duration of Study: Department of Agronomy, College of Agriculture, Padannakkad, Kasaragod, Kerala agricultural University, between May 2023 and March 2024. Methodology: Pellets of biopolymer urea composites (BUCs) were formulated by mixing prilled urea with coconut shell charcoal (C1), gypsum (C2), rice husk biochar (C3), and zeolite (C4) as coating materials and potato starch (S1) and tapioca starch (S2) as binding materials. The experiment was laid out in a Factorial Completely Randomised Design. Castor oil was uniformly sprayed on the composites after formulation. These composites were tested against urea for their nitrogen content and pH. Release behavior of nitrogen in soil and distilled water and leaching behavior in the soil were studied using CRD as the experimental design. The treatments were: T1: Urea, T2: BUC 1, T3: BUC 2, T4: BUC 3, T5: BUC 4, T6: BUC 5, T7: BUC 6, T8: BUC 7, T9: BUC 8 and T10: Control (Soil). Results: Total nitrogen content was not significantly varied across different treatments, but the increase in pH was significant for the treatment, C4. Release of nitrogen in distilled water revealed marked differences among the treatments. Urea exhibited significantly elevated nitrogen release on first day compared to other treatments, whereas T9 and T4 initially showed substantially lower values, which gradually increased, reaching significantly higher levels by day 30. The soil incubation study demonstrated that urea exhibited significantly higher values of ammoniacal and nitrate nitrogen release on the 7th day, reaching their maximum on 14th day and then decreased gradually till 30 days. All other treatments showed significantly lower release of ammonia into the soil, followed by a gradual increase, reaching a maximum at 90 days. Leaching of ammoniacal and nitrate nitrogen was maximum for T1 on day 8. Significantly lower nitrate nitrogen leaching values were recorded by T9 towards the end of the experiment. Conclusion: T9 showed initial release of nitrogen at significantly lower rates. Furthermore, it had a significantly higher pH compared to other treatments, rendering its suitability for acidic soil.

Effects of Long-Term Nitrogen Fertilization on Nitrous Oxide Emission and Yield in Acidic Tea (Camellia sinensis L.) Plantation Soils

The responses of nitrous oxide (N2O) emissions to nitrogen (N) application in acidic, perennial agricultural systems, and the factors driving these emissions, remain poorly understood. To address this gap, a 12-year field experiment was conducted to investigate the effects of different N application rates (0, 112.5, 225, and 450 kg N ha−1 yr−1) on N2O emissions, tea yield, and the associated driving factors in a tea plantation. The study found that soil pH significantly decreased with long-term N application, dropping by 0.32 to 0.85 units. Annual tea yield increased significantly, by 148–243%. N application also elevated N2O emission fluxes by 33–277%, with notable seasonal fluctuations observed. N2O flux was positively correlated with N rates, water-filled pore space (WFPS), soil temperature (Tsoil), and inorganic N (NH4+-N and NO3−-N), while showing a negative correlation with soil pH. Random forest (RF) modeling identified WFPS, N rates, and Tsoil as the most important variables influencing N2O flux. The cumulative N2O emissions for N112.5, N225, and N450 were 1584, 2791, and 45,046 g N ha−2, respectively, representing increases of 1.33, 2.34, and 3.77 times compared to N0. The N2O-N emission factors (EF) were 0.35%, 0.71%, and 0.74%, respectively, and increased with higher N rates. These findings highlight the importance of selecting appropriate fertilization timing and improving water and fertilizer management as key strategies for mitigating soil acidification, enhancing nitrogen use efficiency (NUE), and reducing N2O emissions in acidic tea-plantation systems. This study offers a theoretical foundation for developing rational N fertilizer management practices and strategies aimed at reducing N2O emissions in tea-plantation soils.

Screening Key Genes Related to Nitrogen Use Efficiency in Cucumber Through Weighted Gene Co-Expression Network Analysis.

Cucumber (Cucumis sativus L.) is a crucial vegetable crop, requiring significant nitrogen fertilizer inputs. However, excessive nitrogen application not only impairs growth but also poses severe environmental risks. Thus, enhancing nitrogen use efficiency (NUE) in cucumber is imperative. For the identification of genes associated with NUE in cucumber, roots of high NUE and low NUE lines were analyzed under high nitrogen conditions. Using transcriptome sequencing through WGCNA, a total of 15,180 genes were categorized into 35 co-expression modules, with 5 modules being highly correlated with NUE. Based on differential expression within the five modules and the results of GO and KEGG enrichment analyses, 25 genes were identified as potentially related to NUE. Among these, CsaV4_1G002492 (GLR22), CsaV4_2G003460 (GLR35), CsaV4_3G000307 (NRT1.1), and CsaV4_7G001709 (UPS2) were homologous to genes in Arabidopsis known to directly participate in NUE related process. These four genes were chosen as key genes for further analysis. qRT-PCR analysis revealed that CsaV4_3G000307 and CsaV4_7G001709 were more active during the early stages of the high nitrogen treatment in the high NUE line. Conversely, CsaV4_1G002492 and CsaV4_2G003460 were more active in the low NUE line. Using transcriptomic analysis, a frameshift INDEL mutation was observed in CsaV4_3G000307 in the low NUE line, which impacted the compactness of the protein structure, potentially altering its function. Analysis of protein interactions of these four key genes predicted some potential interaction networks. This research offers critical insights into the genetic factors influencing NUE in cucumber, presenting potential targets for genetic modification or breeding programs.

Overexpression of Phytoglobin1 in Rice Leads to Enhanced Nitrogen Use Efficiency via Modulation of Nitric Oxide.

Nitric oxide (NO) is one of the byproducts of nitrogen metabolism. Excess amount of NO is scavenged by phytoglobins. The role of phytoglobin mediated NO homoeostasis in modulation of nitrate transporters was investigated using NO scavenger cPTIO, phytoglobin overexpressing rice and Arabidopsis. Growing plants under low nitrate leads to generation of reduced levels of NO accompanied by elevated expression of high affinity transporters (HATs) such as NRT2.1, NRT2.3 and NRT2.4. Scavenging of NO by cPTIO under optimal nitrate caused enhanced HATs expression. Phytoglobin overexpressing Arabidopsis showed improved growth and enhanced expression of HATs under low nitrogen in comparison to WT. Pretreatment of optimal nitrate grown plants with NO scavenger cPTIO enhanced HATs expression and shifting of these primed plants from optimal to low nitrate leads to further elevation of HATs expression accompanied by enhanced nitrogen uptake and its accumulation with positive effect on growth. Phytoglobin overexpression in rice leads to enhanced HATs expression, improved growth, nitrogen accumulation under low nitrate. Pgb OE lines showed enhanced accumulation of amino acids. Taken together our results suggest an important role of phytoglobins in nitrogen uptake and assimilation.

Genome-Wide and Transcriptome Analysis of Autophagy-Related ATG Gene Family and Their Response to Low-Nitrogen Stress in Sugar Beet.

Sugar beet (Beta vulgaris L.) is a significant global crop for sugar production, with nitrogen playing a crucial role in its growth, development, and sugar yield. Autophagy facilitates nutrient reabsorption and recycling under nutrient stress by degrading intracellular components, thereby enhancing plant nitrogen use efficiency. However, research on the autophagy response to low-nitrogen stress in sugar beet remains limited. In this study, 29 members of the ATG gene family were identified, with genes within the same subfamily displaying similar gene structures and conserved domains. These ATG genes in sugar beet contain various hormone and stress-response elements. Transcriptome data and qRT-PCR analysis further revealed that the expression levels of ATG4, ATG8b, ATG18a, TOR, NBR1, ATI, ATG8a, ATG12, and VTI12a were significantly upregulated under low-nitrogen stress, with most genes showing high expression levels across different tissues. These ATG genes are thus likely involved in regulating autophagy in response to low-nitrogen conditions. The observed increase in autophagosome numbers further supports the induction of autophagy by low-nitrogen stress. These nine genes can be considered key candidates for further research on nitrogen-sensitive autophagy in the sugar beet ATG gene family. This study provides a comprehensive analysis of the structure and biological functions of ATG genes in sugar beet, offering genetic resources for future efforts to improve sugar beet varieties through genetic engineering. Such efforts could focus on regulating autophagy to enhance nitrogen use efficiency and develop new germplasm.

Urea loaded nanoclay biopolymer composites: synthesis, characterization and evaluation for enhancing nitrogen use efficiency

Urea loaded nanoclay biopolymer composites: synthesis, characterization and evaluation for enhancing nitrogen use efficiency

The role of organic amendments combined with nitrogen fertilizers in enhancing nitrogen use efficiency for wheat in saline calcareous soil

This study investigates the effects of combining different nitrogen fertilizers with organic amendments and Azospirillum brasilense on wheat growth, yield, and nutrient uptake in saline calcareous soil, with a goal of enhancing crop productivity while reducing environmental impacts. The objective was to evaluate treatments involving ammonium sulfate (AS), urea, and sulfur-coated urea (SCU), mixed with organic amendments such as Moringa seed residues (MSR), biogas manure (BM), and vermicompost (Ver), along with Azospirillum brasilense (ASB). Among these treatments, SCU emerged as the most effective nitrogen source, especially when combined with Vermicompost and ASB. Key results include the following: the highest Chlorophyll a content of 1.96 mg/g f wt was observed in the SCU treatment with Ver and ASB; Likewise, the same treatment exhibited the highest values of Chlorophyll b, carotenoids, and proline; the tallest plant height (117.50 cm) was also achieved with this combination; and the highest straw and grain weights (2.63 g/plant and 2.22 g/plant, respectively) came from the same treatment. Additionally, this treatment yielded the highest protein content at 19.29%. In terms of nutrient uptake, SCU-based treatments consistently demonstrated the highest values. The SCU with Ver + ASB treatment recorded the highest nitrogen uptake in straw at 78.64 mg plant−1, phosphorus uptake at 12.86 mg plant−1, and potassium uptake at 61.66 mg plant−1. Similarly, this combination yielded the highest N, P, and K uptake in grains, with 68.05, 10.88, and 53.15 mg plant-1, respectively. e

Field Assessment of Biochar Interactions With Chemical and Biological N Fertilization in Pointed White Cabbage

ABSTRACTThe interaction of biochar with mineral fertilization has attracted attention as a strategy to reduce N losses and enhance nitrogen use efficiency. In this study, we investigated the coapplication of biochar with two optimized fertilization strategies based on split urea and a microbial inoculant (Azospirillum brasilense) in a commercial pointed white cabbage crop. Additionally, we evaluated a third optimized N fertilization alternative, a biochar‐based fertilizer (BBF) enriched in plant‐available N, which was developed from the same biochar. We assessed environmental impacts such as greenhouse gasses (GHG) and NH3 emissions, yield‐scaled N2O emissions, and global warming potential (GWP). Additionally, we evaluated agronomical outcomes such as crop yield, plant N, and chlorophyll concentration. Moreover, we examined the N‐fixing gene's total and relative abundance (nifH and nifH/16S). Biochar and BBF exhibited similar crop yield, GHG, and NH3 emissions compared to split applications of the synthetic fertilizer. The main difference was associated with the higher soil C sequestration in biochar and BBF treatments that reduced the associated GWP of these fertilization strategies. Finally, biochar favored the activity of the N‐fixing bacteria spread, compared to the sole application of bacteria and BBF demonstrated a promoting effect in the soil's total abundance of natural N‐fixing bacteria.

Correction to: Enhanced Nitrogen Use and Economic Benefits in Organic Vegetable Fields via Appropriate Manure Application in Northwestern China

Correction to: Enhanced Nitrogen Use and Economic Benefits in Organic Vegetable Fields via Appropriate Manure Application in Northwestern China

Potassium supply for improvement of cereals growth under drought: A review

AbstractPotassium (K) is an essential macronutrient that determines crop productivity and promotes crop growth under conditions of abiotic stress. In this review paper, peer‐reviewed publications (experimental data) dealing with the role of K administration in the control of cereals growth under drought stress are reviewed and analyzed. Most published research on the impact of K administration on cereals growth under drought focuses primarily on bread wheat (Triticum aestivum L.) and maize (Zea mays L.), along with barley (Hordeum vulgare L.), rice (Oryza sativa L.), pearl millet (Pennisetum glaucum L.), and sorghum (Sorghum bicolor L.). The beneficial effect of K on cereals growth under drought has been related to maintenance of water balance in the crops, increased activity of the antioxidant enzymes, increased synthesis of osmolytes, contribution to a low sodium (Na)/K ratio, extension of the grain filling period, and increase of the grain growth rate and weight. Moreover, K was suggested as a possible way for enhancing nitrogen use efficiency (e.g., bread wheat and sorghum). Nevertheless, the beneficial effect of foliar applied K in dried soil during grain filling differed among bread wheat cultivars, highlighting that the effect of K supply on grain weight may differ depending on application method, that is, administration through the soil or the foliage. Overall, K supply could be exploited as a tool for increasing cereal tolerance to drought, for example, by considering late administration of K through top dressing applications or foliar sprayings. Yet additional information is needed on the rate and the K form, along with the most suitable growth stage for application. Such information could help agronomists develop strategies for high‐quality cereal production in stressful environments.

Partial replacement of inorganic fertilizer with organic inputs for enhanced nitrogen use efficiency, grain yield, and decreased nitrogen losses under rice-based systems of mid-latitudes

In the rice-based system of mid-latitudes, mineral nitrogen (N) fertilizer serves as the largest source of the N cycle due to an insufficient supply of N from organic sources causing higher N losses due to varying soil and environmental factors. However, aiming to improve soil organic matter (OM) and nutrients availability using the best environmentally, socially, and economically sustainable cultural and agronomic management practices are necessary. This study aimed to enhance nitrogen use efficiency (NUE) and grain yield in rice-based systems of mid-latitudes by partially replacing inorganic N fertilizer with organic inputs. A randomized complete block design (RCBD) was employed to evaluate the effects of sole mineral N fertilizer (urea) and its combinations with organic sources—farmyard manure (FYM) and poultry compost—on different elite green super rice (GSR) genotypes and were named as NUYT-1, NUYT-2, NUYT-3, NUYT-4, NUYT-5, and NUYT-6. The study was conducted during the 2022 and 2023 rice growing seasons at the Rice Research Program, Crop Sciences Institute (CSI), National Agricultural Research Centre (NARC), Islamabad, one of the mid-latitudes of Pakistan. The key objective was to determine the most effective N management strategy for optimizing plant growth, N content in soil and plants, and overall crop productivity. The results revealed that the combined application of poultry compost and mineral urea significantly enhanced soil and leaf N content (1.36 g kg− 1 and 3.06 mg cm− 2, respectively) and plant morphophysiological traits compared to sole urea application. Maximum shoot dry weight (SDW) and root dry weight (RDW) were observed in compost-applied treatment with the values of 77.62 g hill− 1 and 8.36 g hill− 1, respectively. The two-year mean data indicated that applying 150 kg N ha⁻1, with half provided by organic sources (10 tons ha⁻1 FYM or poultry compost) and the remainder by mineral urea, resulted in the highest N uptake, utilization, and plant productivity. Thus, integrated management of organic carbon sources and inorganic fertilizers may sustain the productivity of rice-based systems more eco-efficiently. Further research is recommended to explore root and shoot morphophysiological, molecular, and biochemical responses under varying N regimes, aiming to develop N-efficient rice varieties through advanced breeding programs.

Enhancing Wheat Productivity in Pakistan through Nitrogen Management and NDVI Monitoring with Green Seeker

Enhancing sustainability in modern farming systems, it is crucial to minimize environmental pollution from nitrogenous fertilizers by optimizing their application rates. The cost of production for wheat is increasing in Pakistan due to irrational use of nitrogen fertilizers by farming community which are costly and sometimes lead to high vegetative growth causing severe lodging thereby reducing yield. Optimum use of nitrogen (N) fertilizer is therefore empirical to improve the productivity of wheat at a reasonable cost. A field study for two-year was conducted at Ayub Agricultural Research Institute, Faisalabad to manage N fertilizers to enhance nitrogen use efficiency and improve financial return. A sensor-based nitrogen application using Normalized Difference Vegetation Index (NDVI) was compared with farmer practice by using T-test. Results revealed that there was 29% reduction in the use of N and an increase of 12 % in wheat grain yield. Increase in yield with sensor base fertilization improved nitrogen uptake efficiency (39%) and nitrogen fertilizer productivity (59 %) compared to farmer-based N application. The sensor-based management system and the farmer's practices had nitrogen-use efficiencies of 49% and 44%, respectively. The highest net benefits (US$789), benefit cost ratio (1.92) and resource use efficiency (0.864) in sensor-based application of N revealed that the nitrogen management with the help of Green Seeker could be a viable option for enhancing NUE, financial returns and reduction of environmental contamination.

Optimal agronomic measures combined with biochar increased rice yield through enhancing nitrogen use efficiency in soda saline-alkali fields

Soda saline-alkali stress severely hampers rice growth, nitrogen use efficiency, and yield formation. Biochar addition has been recognized as a potential solution to mitigate the adverse effects of saline-alkali stress on crops. Similarly, optimal agronomic measures are known to optimize crop growth conditions and enhance yield formation and resource utilization efficiency. Despite this knowledge, there is limited understanding of the combined effects of optimizing agronomic measures and biochar addition on ionic accumulation, nitrogen use efficiency, and rice yield in soda saline-alkali paddy fields. In this study, a 3-year field experiment was undertaken to evaluate the combined effects of optimal agronomic measures and biochar application on rice physiological properties, nitrogen use efficiency, and yield under five agronomic treatments: zero-fertilizer control (CK), farmers’ practice (FP), high-yield and high-efficiency management (OPT1), super-high-yield management (OPT2), high-yield and high-efficiency management combined with biochar (OPT1+B), and super-high-yield management combined with biochar (OPT2+B). The results demonstrate that treatments of optimal agronomic practices combined with biochar application (OPT2+B and OPT1+B) effectively reduced leaf Na+ concentration, Na+/K+ ratio, abscisic acid (ABA) concentration, and malondialdehyde (MDA) concentration, while enhancing leaf K+ concentration, improving leaf water status, and reducing relative electrical leakage over three years. Furthermore, these combined treatments positively influenced the enzyme activities of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), and leaf nitrogen content (LN), as well as SPAD values. Additionally, the average nitrogen agronomic use efficiency (AEn) increased by 154.71 %, 109.81 %, 50.67 %, and 32.60 % in OPT1+B, OPT2+B, OPT1, and OPT2, respectively, compared to FP, while nitrogen physiological use efficiency (PEn) decreased by 64.03 %, 58.56 %, 29.46 %, and 21.81 %. The average grain yield (GY) increased by 311.42 %, 302.86 %, 196.57 %, 178.86 %, and 133.72 % in OPT2+B, OPT1+B, OPT2, and OPT1, respectively, compared to FP. AEn exhibited positive correlations with K+, leaf water status (LWS), NR, GS, GOGAT, LN, SPAD, and GY. These findings will offer new insights into the sustainable development and utilization of soda saline-alkali lands.

Respuesta morfológica de plántulas de maíz nativo (Zea mays L.) a ambientes contrastantes de nitrógeno

Nitrogen plays a vital role in plant metabolism, influencing growth and development, particularly in crops like maize (Zea mays L.). This study aimed to evaluate the morphological response of maize seedlings to different nitrogen levels. The design was a completely randomized factorial arrangement of 4 x 2, involving four maize cultivars and two nitrogen levels.The variety Sb 302 Berentsen and three native varieties originating from Tecamachalco, Puebla, Mexico were studied. For a period of 14, 21, 28 and 35 days, seedlings were grown in nutrient solution with 10 % and 100 % nitrogen levels under hydroponic conditions. The results revealed significant variability in seedling morphology, particularly in root architecture and dry weight, between the 10 % and 100 % nitrogen treatments. High coefficients of variation were observed in the lengths of crown and seminal roots, alongside significant correlations between root and seedling dry weights at both nitrogen levels. Additionally, a strong correlation was found between root length and number under the 10 % nitrogen treatment. The results highlight the critical role of nitrogen in maize seedling development and the interaction between nitrogen concentration and maize variety, particularly in primary root length. The study improves understanding of nitrogen's role in optimizing maize growth and suggests strategies to enhance nitrogen use efficiency across different maize varieties. Keywords: cereals, nitrogen use efficiency, root architecture, native varieties.

Enhancing crop productivity and nitrogen use efficiency by application of pine oleoresin coated urea in maize-wheat cropping sequence in vertisols

Enhancing crop productivity and nitrogen use efficiency by application of pine oleoresin coated urea in maize-wheat cropping sequence in vertisols

Comparative phenotypic and transcriptomic analysis reveals genotypic differences in nitrogen use efficiency in sorghum

Sorghum (Sorghumbicolor L.), a model for C4 grass and an emerging biofuel crop, is known for its robust tolerance to low input field. However, the focus on enhancing nitrogen use efficiency (NUE) in sorghum under low nitrogen (N) conditions has been limited. This study conducted hydroponic experiments and field trials with two sorghum inbred lines, contrasting in their N efficiency: the N-efficient (398B) and the N-inefficient (CS3541) inbred lines. The aim was to analyze the key factors influencing NUE by integrating phenotypic, physiological, and multi-omics approaches under N deficiency conditions. The field experiments revealed that 398B displayed superior NUE and yield performance compared to CS3541. In hydroponic experiments, the growth of 398B outperformed CS3541 following N deficiency, attributing to its higher photosynthetic and sustaining activity of N metabolism-related enzymes. Genomic and transcriptomic integration highlighted fewer genomic diversities and alterations in global gene expression in 398B, which were likely contributor to its high NUE. Additionally, co-expression network analysis suggested the involvement of key genes which impact N uptake efficiency (NUpE) and N utilization efficiency (NUtE) in both lines, such as an N transporter, Sobic.003G371000.v3.2leaf(NPF5.10) and a transcription factor, Sobic.002G202800.v3.2leaf(WRKY) in bolstering NUE under low-N stress. The findings collectively suggested that 398B achieved higher NUpE and NUtE, effectively coordinating photosynthesis and N metabolism to enhance NUE. The candidate genes regulating N uptake and utilization efficiencies could provide valuable insights for developing sorghum breeds with improved NUE, contributing to sustainable agricultural practices and bioenergy crop development.

Integrated management strategies increased silage maize yield and quality with lower nitrogen losses in cold regions.

High-yield and high-quality production of silage maize in cold regions is crucial for ensuring the sustainable development of livestock industry. This study first conducted an experiment to select the optimized silage maize varieties and densities using a split-plot design. The tested maize varieties were Xuntian 3171, Xuntian 16, Xunqing 858, and Fengtian 12, with each variety planted at densities of 67,500, 79,500, and 90,000 plants ha-1. Following the variety and density selection, another experiment on optimizing nitrogen management for silage maize was carried out using a completely randomized design: no nitrogen fertilizer (T1), applying urea-N 320 kg ha-1 (T2), applying urea-N 240 kg ha-1 (T3), applying polymer-coated urea-N 240 kg N ha-1 (T4), and ratios of polymer-coated urea-N to urea-N at 9:1 (T5), 8:2 (T6), 7:3 (T7), and 6:4 (T8). T5-T8 all applied 240 kg N ha-1. The yield and quality of silage maize, nitrogen use efficiency and balance, and economic benefits were evaluated. Results showed that Xunqing 858 had significantly higher plant height (8.7%-22.6% taller than the other three varieties) and leaf area (30.9% larger than Xuntian 3171), resulting in yield 11.5%-51.6% higher than the other three varieties. All varieties achieved maximum yields at a planting density of 79,500 plants ha-1. Integrated management strategy 7 (T7: Xunqing 858, 79,500 plants ha-1, polymer-coated urea-N to urea-N ratio of 7:3) achieved the highest yield of 73.1 t ha-1, a 6.1%-58.1% increase over other treatments. This strategy also produced the highest crude protein (11.1%) and starch (19.1%) contents, and the lowest neutral detergent fiber content (50.6%), with economic benefits improved by 10.3%-97.8% compared to other strategies. Additionally, T7 improved nitrogen use efficiency by 15.4%-94.5%, reduced soil nitrate leaching by 4.4%-36.5%, and decreased nitrogen surplus by 7.0%-46.6%. Comprehensive analysis revealed that the integrated management strategy 7 significantly improved silage maize yield and quality in cold regions while enhancing nitrogen use efficiency and reducing the risk of nitrate leaching, aligning with green agriculture development requirements. These findings will provide vital theoretical insights and practical guidance for high-yield and high-quality silage maize production in cold regions worldwide.

Straw returning and nitrogen reduction: Strategies for sustainable maize production in the dryland

Implementing continue straw returning practices and optimizing nitrogen application can mitigate nitrogen losses and enhance nitrogen use efficiency (NUE) in dryland. 15N-labeled technique offers a robust approach for tracking fertilizer nitrogen fate and assessing nitrogen use efficiency. Based on the continue (>6 yr) experiment, we conducted a two-year experiment (2020 and 2021) to evaluate the effects of straw returning and nitrogen management under plastic film mulching on 15N recovery rates, N2O emissions and maize yield with three treatments: no straw returning with 225 kg N·ha−1 under plastic film mulching (RP-N225), straw returning with 225 kg N·ha−1 under plastic film mulching (RPS-N225), and straw returning with 20% nitrogen reduction (180 kg N·ha−1) under plastic film mulching (RPS-N180). After six years, both continue straw returning with plastic film mulching increased uptake of fertilizer nitrogen, had higher 15N recovery rates than RP-N225, leading to increased 15N accumulation in grain and aboveground biomass, ultimately enhancing yield. The RPS-N225 treatment exhibited the highest spring maize yield and nitrogen harvest index. The RPS-N180 treatment significantly increased maize yield more than RP-N225 and had the highest NUE, partial factor productivity of nitrogen fertilizer, and nitrogen uptake efficiency, with improvements ranging from 1.7 to 2.4%, 19.3–29.6%, and 17.3–27.5%, respectively, compared to the other treatments. Moreover, RPS-N225 resulted in significantly higher cumulative N2O emissions and yield-scaled N2O emissions than the other treatments, whereas the RPS-N180 treatment significantly decreased yield-scaled N2O emissions compared to RP-N225. Hence, combining continue straw returning with appropriate nitrogen reduction can effectively increase maize yield and yield-scaled N2O emissions. By offering insights into optimizing nitrogen fertilizer management after continue maize straw return, this study is contributed to widespread adoption of straw return practices and sustainable agricultural development in semi-arid areas.

Research Hotspots and Trends of Nitrification Inhibitors: A Bibliometric Review from 2004–2023

Nitrification inhibitors are essential in agricultural and environmental production practices. They play a crucial role in promoting agricultural and environmental sustainability by enhancing nitrogen use efficiency, boosting crop yields, and mitigating the adverse environmental effects of nitrogen losses. This bibliometric analysis covers the period from 2004 to 2023, offering a detailed examination of the development of nitrification inhibitor research. The study demonstrates a consistent growth in research publications, indicating sustained interest and dedication to advancing the field. It identifies key contributors, such as institutions and researchers, and underscores the significance of their work through citation analysis. Keyword co-occurrence analysis reveals four distinct clusters focusing on enhancing crop yields, understanding microbial community dynamics, exploring grazing pasture applications, and addressing environmental impact mitigation. The cutting-edge area of keyword burst detection research has transitioned from fundamental research to comprehensive nitrogen management practices. This analysis provides insights into the current research landscape of nitrification inhibitors and proposes future research directions, underscoring the critical role of this field in tackling global agricultural and environmental challenges.

Enhancing nitrogen use efficiency in cereal crops: from agronomy to genomic perspectives

Enhancing nitrogen use efficiency in cereal crops: from agronomy to genomic perspectives