Nitrogen Fertilizer Production Research Articles

Estimating the global warming potential of animal waste-based organic liquid fertilizer for urban hydroponic farms

Urban farms, particularly those utilizing vertical space and hydroponics, have the potential to address many challenges of the existing food system. The use of organic inputs in hydroponics can conserve dwindling non-renewable resources and mitigate greenhouse gas (GHG) emissions associated with inorganic nitrogen (N) fertilizer production and use. The study compared plant growth using organic liquid fertilizer (OLF) from insect and chicken waste in a two-step aerobic bioreactor. Basil (Ocimum basilicum) plants were grown with an inorganic fertilizer control and a novel OLF at two separate locations. In the first part of the study, plant yield, nutrient uptake and tissue elemental composition were used to validate the functional equivalency of OLF versus inorganic fertilizer. The second part of the study used these results to conduct a life-cycle assessment (LCA) to quantify GHG mitigation potential of the novel OLF. N-mass balance showed a liquid nitrogen conversion rate ∼40% for the bioreaction. Solid output from the bioreaction contained approximately 35% of the initial N. N-gaseous loss was approximately 25% of total N-input. Because the nature of gaseous N-loss was unknown, LCA modeled different scenarios varying the percent of gaseous N-loss as N2O, as it is the only nitrogen-based gas with appreciable global warming potential. Models showed that N2O leakage during bioreaction must be below 5% of total N-input for OLF to mitigate GHG emissions associated with fertilizer usage in urban hydroponic production. Further studies should focus on direct quantification and characterization of gaseous N-loss during this type of bioreaction.

The Use of Low-Cost Drone and Multi-Trait Analysis to Identify High Nitrogen Use Lines for Wheat Improvement

Breeding for nitrogen use efficiency (NUE) is becoming more important as global uncertainty makes the production and application of nitrogen (N) fertilizers more expensive and environmentally unfriendly. Despite this, most cereal breeding programs still use yield-related components as proxies for NUE, likely due to the prohibitive cost and time of collecting and analyzing samples through traditional lab-based methods. Drone-based NUE phenotyping provides a viable and scalable alternative as it is quicker, non-destructive, and consistent. Here, we present a study that utilized financially accessible cost-effective drones mounted with red-green-blue (RGB) image sensors coupled with the open-source AirMeasurer platform and advanced statistical analysis to exclude low-NUE lines in multi-seasonal field experiments. The method helped us to identify high N agronomic use efficiency lines but was less effective with a high N recovery efficiency line. We found that the drone-powered approach was very effective at 180 kg N per hectare (N180, an optimized N-rate) as it completely removed low-NUE wheat lines in the trial, which would facilitate breeders to quickly reduce the number of lines taken through multi-year breeding programs. Hence, this encouraging and scalable approach demonstrates its ability to conduct NUE phenotyping in wheat. With continuous refinements in field experiments, this method would be employable as an openly accessible platform to identify NUE lines at different N-rates for breeding and resource use efficiency studies in wheat.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode.

Transformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co-reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g-1 h-1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (-0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C-N coupling is the rate-determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co-reduction of CO2 and NO3 - to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value-added chemical synthesis.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode

AbstractTransformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co‐reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g−1 h−1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (−0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C−N coupling is the rate‐determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co‐reduction of CO2 and NO3− to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value‐added chemical synthesis.

Sustainable nitrogen fixation by novel gliding arc plasma reactor for the production of nitrogen fertilizers

AbstractA novel plasma reactor is being investigated for green NOx production, crucial for nitrate‐based fertilizer manufacturing. Various parameters, including air flow rates, gas ratios, ozone, and catalyst effects are explored for NO → NO2 conversion. NOx concentrations reach ~0.6 vol%, with a total production of ~9.7 gr/h and energy cost of ~3.0 mJ/mol, notably favorable for atmospheric gliding arc plasma. Selectivity (~75%) towards NO2 is achieved with ozone addition or catalytic treatment, pivotal for nitrate fertilizer and HNO3 production.

Global potential nitrogen recovery from anaerobic digestion of agricultural residues

Meeting the anticipated 50% increase in global food demand by 2050 requires a crucial reassessment of agricultural practices, particularly in terms of nitrogen fertilizers inputs. This study analyzes the technical potential of nitrogen recovery from livestock manure and crop residues, bringing attention to the often-overlooked resource of digestate derived from anaerobic digestion. Our analysis highlights the significant capacity of the anaerobic digestion process, yielding approximately 234 ± 5 million metric tons (Mt) of nitrogen annually, sourced 93% from livestock manure and 7% from crop residues. Additionally, we estimated that substituting synthetic nitrogen with nitrogen from anaerobic digestion has the potential to reduce greenhouse gas emissions by 70% (185 Mt CO2-eq yr−1). Lastly, 2.5 billion people could be sustained by crops grown using nitrogen from anaerobic digestion of manure and crop residues rather than synthetic nitrogen fertilizers. Although agricultural residues have double the technical potential of current synthetic nitrogen fertilizer production, 30% of croplands encounter difficulties in satisfying their nitrogen needs solely through crop residues and anaerobic digestion manure. This deficiency primarily results from inefficient reuse attributed to geographical mismatches between crop and livestock systems. This underscores the urgent need to reconnect livestock and cropping systems and facilitate the transport and reuse of manure in crop production. In conclusion, the mobilization of these large amounts of nitrogen from livestock manure and crop residues will require to overcome the nitrogen from anaerobic digestion green premium with incentives and subsidies.

Enhancing selective ammonium transport in membrane electrochemical systems

Recovering ammonia nitrogen from wastewater is a sustainable strategy that simultaneously addresses both nitrogen removal and fertilizer production. Membrane electrochemical system (MES), which utilizes electrochemical redox reactions to transport ammonium ions through cation exchange membranes, has been considered as an effective technology for ammonia recovery from wastewater. In this study, we develop a mathematical model to systematically investigate the impact of co-existing ions on the transport of ammonium (NH4+) ions in MES. Our analysis elucidates the importance of pH values on both the NH4+ transport and inert ion (Na+) transport. We further comprehensively assess the system performance by varying the concentration of Na+ in the system. We find that while the inert cation in the initial anode compartment competes with NH4+ transport, NH4+ dominates the cation transport in most cases. The transport number of Na+ surpasses NH4+ only if the fraction of Na+ to total cation is extremely high (>88.5%). Importantly, introducing Na+ ions into the cathode compartment significantly enhances the ammonia transport due to the Donnan dialysis. The analysis of selective ion transport provides valuable insights into optimizing both selectivity and efficiency in ammonia recovery from wastewater.

Utilizing plasma-generated N2O5 gas from atmospheric air as a novel gaseous nitrogen source for plants

Fixing atmospheric nitrogen for use as fertilizer is a crucial process in promoting plant growth and enhancing crop yields in agricultural production. Currently, the chemical production of nitrogen fertilizer from atmospheric N2 relies on the energy-intensive Haber–Bosch process. Therefore, developing a low-cost and easily applicable method for fixing nitrogen from the air would provide a beneficial alternative. In this study, we tested the utilization of dinitrogen pentoxide (N2O5) gas, generated from oxygen and nitrogen present in ambient air with the help of a portable plasma device, as a nitrogen source for the model plant Arabidopsis thaliana. Nitrogen-deficient plants supplied with medium treated with N2O5, were able to overcome nitrogen deficiency, similar to those provided with medium containing a conventional nitrogen source. However, prolonged direct exposure of plants to N2O5 gas adversely affected their growth. Short-time exposure of plants to N2O5 gas mitigated its toxicity and was able to support growth. Moreover, when the exposure of N2O5 and the contact with plants were physically separated, plants cultured under nitrogen deficiency were able to grow. This study shows that N2O5 gas generated from atmospheric nitrogen can be used as an effective nutrient for plants, indicating its potential to serve as an alternative nitrogen fertilization method for promoting plant growth.

Nitrogen fixation‐driven carbon sequestration: Brief communication

AbstractPrior to the commercial nitrogen fertilizer production in 1919, all the world's terrestrial and aquatic carbon was supported by nitrogen fixation. Annual N deposition to semi‐arid lands and temperate forests is less than 5 kg/ha‐year and 10 kg/ha, respectively. Plant and soil C/N ratios range from 9.9 to 29.8 and 9 to 14, respectively. In an equilibrium, sustainable ecosystem where N is not removed from soil pools and is only dependent on annual N inputs, maximum C sequestration rates are approximately 3.25 kg to 46 kg/ha for arid ecosystems and 23 to 101 kg/ha for forest ecosystems. Commercial N applications range from approximately 70 to 160 kg/ha‐year. Managed nitrogen fixation rates range from approximately 50 to 130 kg N/ha‐year. For each additional kg N‐entering forests, the additional C is approximately 13 kg. N‐fixing plants range from alder and lupines in the arctic, to Prosopis and Acacias in semi‐arid lands and the large trees Inga and Pentaclethra in tropical rainforests. If N‐fixing plants achieving 50 kg N/ha‐year were planted on the equivalent of a 447 km square, on six continents, the IEA target of 1.7Gt CO2 (0.72 Gt of carbon) capture capacity by 2030 https://www.ief.org/news/whats‐the‐target‐for‐carbon‐sequestration‐and‐how‐do‐we‐get‐there could be achieved.

Highly efficient and selective electrosynthesis of urea via co-reduction of carbon dioxide and nitrate over the TiNx catalyst

Green and sustainable electrosynthesis of urea at ambient conditions through co-reduction of CO2 and NO3− (CR-CO2/NO3−) is regarded as a new avenue for nitrogen fertilizer production, however, the lack of novel electrocatalysts capable of selective C-N coupling hinders its wide application. Herein we reported a TiNx catalyst (TiN/TiN0.3) prepared by facile electric explosion method for electrocatalytic urea synthesis via CR-CO2/NO3−. The derived catalyst with porous nanostructure and specific active phase (TiN0.3) is more conductive for efficient C-N coupling. Consequently, a faradaic efficiency (FE) of 43.1 ± 3.1 % and a urea formation rate as high as 1488 ± 95 μg h−1 mgcat−1 were reached over the TiNx electrode, outperforming most of the reported CR-CO2/NO3− systems toward urea synthesis. In-situ attenuated total reflection Fourier transformed infrared spectroscopy and isotope-labeling experiments demonstrated the details about electrochemical coupling processes. The simulation study suggested that the TiN0.3 (100) facet facilitates the electroreduction of CO2 and NO3−, and decreases the energy barrier for generation of the key intermediates (*CO/*NH2), thus leading to the selective formation of urea. This work accomplished highly efficient electrochemical CR-CO2/NO3− toward nitrogen fertilizer production over a novel TiNx electrocatalyst for the target process.

Sewage sludge-derived nutrients and biostimulants stimulate rice leaf photosynthesis and root metabolism to enhance carbohydrate, nitrogen and antioxidants accumulation

The production of high quality liquid nitrogen fertilizer with both nutrient comprehensive and biostimulant properties by alkaline thermal hydrolysis of sewage sludge has shown great potential in agricultural production. However, little is known about the effects of sewage sludge-derived nutrients, and biostimulants (SS-NB) on leaf photosynthesis and root growth in rice. Phenotypic, metabolic and microbial analyses were used to reveal the mechanism of SS-NB on rice. Compared to NF treatment, phenotypic parameters (fresh/dry weight, soluble sugar, amino acid, protein) were increased by SS-NB in rice. SS-NB can enhance the photosynthesis of rice leaves by improving the photoconversion efficiency, chlorophyll content, ATP synthase activity, Rubisco and NADPH production. Meanwhile, SS-NB also increased antioxidant capacity (SOD, POD, CAT and proline) in rice leaf and root tissues. Metabolomics revealed that SS-NB application increased the expression levels of metabolites in root and leaf tissues, including carbohydrate, nitrogen and sulfur metabolism, amino acid metabolism, antioxidants, and phytohormone. Most importantly, the regulation of metabolites in rice root tissues is more sensitive than in leaf tissues, especially to the higher levels of antioxidants and phytohormones (IAA and GA) in rice root tissues. Furthermore, SS-NB increased the abundance of photosynthetic autotrophic, organic acids-degrading and denitrifying functional bacteria in rice roots and recruited plant growth-promoting bacteria (Azospirillum and norank_f_JG30-KF-CM45), while the NF treatment group resulted in an imbalance of the microbial community, leading to the dominance of pathogenic bacteria. The results showed that SS-NB had great application potential in crop growth and stress resistance improvement.

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.

Problems of fertilizer application in developed agriculture and their solution

One of the important ways to obtain heavy and high-quality crops is to increase soil fertility by fertilizing to a level that fully meets the needs of crops in nutrients. According to the results of the research, the function and role of fertilizers in increasing crop yields were revealed. The data on the production and use of nitrogen, phosphorus and potash mineral fertilizers in Uzbekistan and worldwide were summarized. The ways of increasing soil fertility and crop yields through the use of fertilizers are outlined.

An appropriate ammonium: nitrate ratio promotes the growth of centipedegrass: insight from physiological and micromorphological analyses.

Reasonable nitrogen fertilizer application is an important strategy to maintain optimal growth of grasslands, thereby enabling them to better fulfil their ecological functions while reducing environmental pollution caused by high nitrogen fertilizer production and application. Optimizing the ammonium (NH4 +):nitrate (NO3 -) ratio is a common approach for growth promotion in crops and vegetables, but research on this topic in grass plants has not received sufficient attention. Centipedegrass, which is widely used in landscaping and ecological protection, was used as the experimental material. Different NH4 +:NO3 - ratios (0: 100, 25:75, 50:50, 75:25, 100:0) were used as the experimental treatments under hydroponic conditions. By monitoring the physiological and morphological changes under each treatment, the appropriate NH4 +:NO3 - ratio for growth and its underlying mechanism were determined. As the proportion of ammonium increased, the growth showed a "bell-shaped" response, with the maximum biomass and total carbon and nitrogen accumulation achieved with the NH4 +:NO3 - ratio of 50:50 treatment. Compared with the situation where nitrate was supplied alone, increasing the ammonium proportion increased the whole plant biomass by 93.2%, 139.7%, 59.0%, and 30.5%, the whole plant nitrogen accumulation by 44.9%, 94.6%, 32.8%, and 54.8%, and the whole plant carbon accumulation by 90.4%, 139.9%, 58.7%, and 26.6% in order. As a gateway for nitrogen input, the roots treated with an NH4 +:NO3 - ratio of 50:50 exhibited the highest ammonium and nitrate uptake rate, which may be related to the maximum total root length, root surface area, average root diameter, root volume, and largest root xylem vessel. As a gateway for carbon input, leaves treated with an NH4 +:NO3 - ratio of 50:50 exhibited the highest stomatal aperture, stomatal conductance, photosynthetic rate, transpiration rate, and photosynthetic products. The NH4 +:NO3 - ratio of 50:50 treatment had the largest stem xylem vessel area. This structure and force caused by transpiration may synergistically facilitate root-to-shoot nutrient translocation. Notably, the change in stomatal opening occurred in the early stage (4 hours) of the NH4 +:NO3 - ratio treatments, indicating that stomates are structures that are involved in the response to changes in the root NH4 +:NO3 - ratio. In summary, we recommend 50:50 as the appropriate NH4 +:NO3 - ratio for the growth of centipedegrass, which not only improves the nitrogen use efficiency but also enhances the carbon sequestration capacity.

Trade‐off between soil carbon sequestration and net ecosystem economic benefits for paddy fields under long‐term application of biochar

AbstractThe application of biochar and nitrogen fertilizer can increase rice yield, soil organic carbon (SOC) storage and reduce greenhouse gas (GHG) emissions. However, few studies have systematically evaluated the carbon footprint (CF) and net ecosystem economic benefits (NEEB) of paddy ecosystems under long‐term application of biochar and nitrogen fertilizer. Here, the life cycle assessment method was used to quantify the CF and NEEB of paddy fields under different biochar and nitrogen fertilizer application rates in 7 years. Three biochar rates of 0 (B0), 4.5 (B1) and 13.5 t ha−1 year−1 (B2) and two nitrogen fertilizer rates of 0 (N0) and 300 kg ha−1 year−1 (N) were set. The results showed that B2 significantly increased methane (CH4) emission by 38%, decreased nitrous oxide (N2O) emission by 29%, and significantly increased global warming potential by 27% compared with B0. Besides that, biochar application significantly increased ΔCSOC by 87%–173% and reduced CF by 1.6–1.8 Mg CO2 eq ha−1. Among them, CH4 and N2O emissions contributed 46%–95% of total GHG emissions, and the production and transportation of nitrogen fertilizer and biochar contributed 17%–52% of total GHG emissions. Nitrogen fertilizer application can significantly increase rice yield by 85% compared to the N0, which could bring the largest NEEB. Biochar application had a negative influence on the NEEB regardless of N application. This might be attributable to the fact that the economic gains from increased rice production and SOC caused by biochar cannot outweigh the high cost of biochar. These results suggest that the biochar application can significantly improve the SOC sequestration and reduce the CF, but also had negative effect on NEEB in paddy filed.

Effect of single basal application of controlled-release blended fertilizer on reactive nitrogen loss, carbon and nitrogen footprint during summer maize growth period

To elucidate the agronomic and environmental effects of single basal application of controlled-release blended fertilizer in summer maize, and optimize management measures of nitrogen fertilizer for grain production in North China Plain, we conducted a field experiment in Dezhou Modern Agricultural Science and Technology Park in Shandong Province. There were four treatments: CK (no N fertilizer), FFP (farmer's fertilizing practice, 240 kg N·hm-2), OPT (optimized nitrogen application, 210 kg N·hm-2), and CRBF (controlled-release blended fertilizer with single basal application, 210 kg N·hm-2). We compared maize yield and reactive nitrogen loss, and quantitatively evaluated the carbon and nitrogen footprints by using life cycle assessment method. The results showed that nitrogen application significantly increased summer maize yield. Compared with FFP, OPT and CRBF increased summer corn yield by 0.7% and 2.9%, respectively, decreased the total amount of ammonia volatilization, N2O emission, and nitrate leaching by 13.0% and 72.7%, 13.3% and 37.5%, 20.5% and 23.5% respectively. Compared with CK, nitrogen application significantly increased the global warming potential (GWP) of summer maize production. Compared with FFP, GWP and greenhouse gas emission intensity of OPT decreased by 3.8% and 4.2%, while the reduction of CRBF were 8.7% and 12.0%, respectively. Compared with CK, nitrogen application significantly increased the carbon and nitrogen footprint of summer maize production. The production and transportation of nitrogen fertilizer and soil greenhouse gas emission were the main contributing factors of the carbon footprint, with contribution rates of 54%-60% and 24%-31%, respectively. Nitrate leaching was the main contributing factor of nitrogen footprint, with contribution rate of 57%-94%. Compared with FFP, the carbon and nitrogen footprints of OPT and CRBF were reduced by 11.0% and 16.5%, 19.6% and 28.4%, respectively. Considering the yield, reactive nitrogen loss and carbon and nitrogen footprint, we recommended the single basal application of controlled-release blended fertilizer as an effective nitrogen fertilizer management measure to promote grain clean production in the North China Plain.

US climate policy yields water quality cobenefits in the Mississippi Basin and Gulf of Mexico

We utilize a coupled economy-agroecology-hydrology modeling framework to capture the cascading impacts of climate change mitigation policy on agriculture and the resulting water quality cobenefits. We analyze a policy that assigns a range of United States government's social cost of carbon estimates ($51, $76, and $152/ton of CO2-equivalents) to fossil fuel-based CO2 emissions. This policy raises energy costs and, importantly for agriculture, boosts the price of nitrogen fertilizer production. At the highest carbon price, US carbon emissions are reduced by about 50%, and nitrogen fertilizer prices rise by about 90%, leading to an approximate 15% reduction in fertilizer applications for corn production across the Mississippi River Basin. Corn and soybean production declines by about 7%, increasing crop prices by 6%, while nitrate leaching declines by about 10%. Simulated nitrate export to the Gulf of Mexico decreases by 8%, ultimately shrinking the average midsummer area of the Gulf of Mexico hypoxic area by 3% and hypoxic volume by 4%. We also consider the additional benefits of restored wetlands to mitigate nitrogen loading to reduce hypoxia in the Gulf of Mexico and find a targeted wetland restoration scenario approximately doubles the effect of a low to moderate social cost of carbon. Wetland restoration alone exhibited spillover effects that increased nitrate leaching in other parts of the basin which were mitigated with the inclusion of the carbon policy. We conclude that a national climate policy aimed at reducing greenhouse gas emissions in the United States would have important water quality cobenefits.

Effects of Straw Biochar on Carbon Footprint of Maize Farmland Ecosystem Under Mulched Drip Irrigation in Hetao Irrigation District

To explore the effect of biochar on greenhouse gas emissions and the carbon footprint of a corn farmland ecosystem under drip irrigation with film in an arid region, biochar treatments with different application rates[0 (CK), 15 (C15), 30 (C30), and 45 t·hm-2 (C45)] were established. The seasonal changes in soil greenhouse gases (CO2, N2O, and CH4) and their comprehensive warming potential in the maize farmland ecosystem were monitored for two consecutive years after a one-time application of biochar. The carbon emissions caused by agricultural production activities and their carbon footprint were estimated using the life cycle assessment method. Compared with that in CK, the cumulative CO2 emissions in the crop growing season decreased by 17.6%-24.7%, the cumulative N2O emissions decreased by 71.1%-110.4%, and the global warming potential decreased by 19.5%-25.9%. In the second year of the crop growing season after biochar application, the cumulative CO2 emissions were reduced by 19.2%-40.6%, the cumulative N2O emissions were reduced by 38.7-46.7%, and the comprehensive warming potential was reduced by 19.7%-40.5%. For two consecutive years, the treatment of C15 and C30 increased the cumulative absorption of CH4 to different degrees, whereas the treatment of C45 significantly decreased the cumulative absorption of CH4. C15 and C45 were the treatments with the least carbon footprint per unit yield in the current and the succeeding year of biochar application, and their carbon footprint per unit yield was 10.1% and 26.2% lower than that of CK, respectively. Soil greenhouse gas emissions showed the most contribution to the carbon footprint of the maize farmland ecosystem (38.1%-59.2%), followed by nitrogen fertilizer production (19.8%-33.4%), electric energy production (6.7%-8.8%), and plastic film mulching (4.4%-7.4%). Biochar contributed 5.7%-13.8% to the ecosystem's carbon footprint. The application of 30 t·hm-2 biochar had a better effect on carbon reduction, carbon fixation, and yield increase in the farmland ecosystem. Improving the biochar production process and transportation route, increasing nitrogen use efficiency, and developing water-saving and energy-saving irrigation technology are important ways to reduce the carbon footprint of farmland ecosystems in arid regions.

An Analytical Economic Study of the Production and Consumption of Nitrogen Fertilizers in Egypt

An Analytical Economic Study of the Production and Consumption of Nitrogen Fertilizers in Egypt

Optimizing Renewable Ammonia Production for a Sustainable Fertilizer Supply Chain Transition.

Local renewable ammonia production using electrolytic hydrogen is an emerging approach to alleviate emissions attributed to synthetic nitrogen fertilizer production while also insulating against fluctuations in fertilizer prices and mitigating transportation costs and emissions. However, replacing ammonia currently produced using fossil fuels will not be immediate. To this end, we develop a supply chain transition model, which first optimizes the design and hourly operation of new renewable ammonia facilities to minimize production costs and then optimizes the annual installation timing, production scale, and location of these new renewable facilities along with ammonia transportation to meet county resolution demands. The objective is to augment and eventually replace conventional ammonia market imports in an economically competitive manner. We performed a case study for Minnesota's ammonia supply chain and found that a full transition to in-state renewable production by 2032 is optimal. This is incentivized by the U.S. federal government's clean hydrogen production credits. This transition results in 99 % reduction in carbon intensity along with stable supply costs below $475 per metric tonne. New renewable production facilities are an order of magnitude smaller than existing conventional plants. They use both wind and solar resources and operate dynamically to minimize expensive battery and hydrogen storage capacities.