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Review

Plasma-Activated Water as a Sustainable Nitrogen Source: Supporting the UN Sustainable Development Goals (SDGs) in Controlled Environment Agriculture

by
Pamela Estefania Andrade
1,2,
Patrice Jacob Savi
2,
Flavia Souza Almeida
3,
Bruno Augusto Carciofi
3,
Abby Pace
4,
Yugeng Zou
2,
Nathan Eylands
5,
George Annor
6,
Neil Mattson
4 and
Christian Nansen
2,*
1
Escuela de Biología, Universidad del Azuay, Cuenca 010204, Ecuador
2
Department of Entomology and Nematology, University of California Davis, Davis, CA 95616, USA
3
Department of Biological and Agricultural Engineering, University of California Davis, Davis, CA 95616, USA
4
Horticulture Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14850, USA
5
Department of Horticultural Science, University of Minnesota, Saint Paul, MN 55455, USA
6
Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN 55455, USA
*
Author to whom correspondence should be addressed.
Crops 2025, 5(3), 35; https://doi.org/10.3390/crops5030035
Submission received: 3 April 2025 / Revised: 16 May 2025 / Accepted: 26 May 2025 / Published: 6 June 2025
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Abstract

Global agriculture remains dependent on nitrogen fertilizers produced through fossil fuel-based processes, contributing to greenhouse gas emissions, energy use, and supply chain vulnerabilities. This review introduces plasma-activated water (PAW) as a novel, electricity-driven alternative for sustainable nitrogen delivery. Generated by non-thermal plasma, PAW infuses water with reactive oxygen and nitrogen species, offering a clean, decentralized substitute for conventional synthetic fertilizers derived from the Haber–Bosch and Ostwald processes. It can be produced on-site using renewable energy, reducing transportation costs and depending on fertilizers. Beyond its fertilizer properties, PAW enhances seed germination, plant growth, stress tolerance, and pest resistance, making it a multifunctional input for controlled environment agriculture. We also assess PAW’s techno-economic viability, including energy requirements, production costs, and potential scalability through renewable energy. These factors are crucial for determining its feasibility in both industrial systems and localized agricultural applications. Finally, the review examines PAW’s contribution to the ten United Nations Sustainable Development Goals, particularly in climate action, clean energy, and sustainable food production. By combining agronomic performance with circular production and emissions reduction, PAW presents a promising path toward more resilient, low-impact, and self-sufficient agricultural systems.

1. Introduction

The global human population of about 8 billion today is estimated to reach 10 billion by 2050 [1]. As food demand rises with population growth, commercial and large-scale food production will become even more reliant on ways to obtain nitrogen fertilizer to grow crops in ways that are both economically and environmentally sustainable. Accordingly, it is valid and important to view challenges associated with a global human population through the prism of nitrogen fertilizers. Moreover, the demand for nitrogen fertilizer has been steadily growing each year, and in 2024 it was estimated to be approximately 108 million metric tons [2]. To the best of our knowledge, there are no accurate global percentage estimates on the use of synthetic versus organic (compost, manure, cover crops) nitrogen fertilizers in crop production. However, it has been estimated that about 2% of the world’s agricultural land is managed organically, while the remaining 98% is under conventional farming practices [3]. If so, the global use of synthetic nitrogen fertilizer per year in crop production may be about 106 million metric tons (Table 1).
Synthetic fertilizers typically provide nitrogen in three chemical forms: nitrate (NO3−), ammonium (NH4+), and urea [CO(NH2)2]. These chemical forms of nitrogen are typically derived from precursors, such as ammonia (NH3) via the Haber–Bosch process, and nitric acid (HNO3) via the Ostwald process [11]. Around 95% of the annual hydrogen production, primarily used in ammonia and nitric acid manufacturing, comes from fossil fuels, such as natural gas, oil, and coal, resulting in a significant carbon footprint [12]. It requires large amounts of energy to break covalent bonds between H-H and N≡N. In the Haber–Bosch process, steam reforming consumes about 75% of the total energy, performing at 1120–1170 K and 25–35 atm to produce hydrogen [13]. Nitrogen production requires a similar energy input [11,12]. Ammonia synthesis is performed at 723–823 K and 250–350 atm [13], and establishment and maintenance of such conditions require large amounts of energy. The Ostwald process also requires high energy for nitric acid production, with ammonia oxidation operating at 975–1225 K and 4–10 atm. Extra oxidation and absorption steps add to the total energy consumption [13]. Essentially, conventional ammonia production through the Haber–Bosch process requires 39 GJ of energy per ton of fixed nitrogen and consumes 5.5 EJ of global energy annually, which represents 11% of the chemical industry’s energy use [13]. Nitric acid, produced through the Ostwald process consumes 66.6 GJ per ton of fixed nitrogen and contributes to an additional 0.6 EJ of global energy use per year [14]. The Haber–Bosch and Ostwald processes are interdependent, as ammonia from the Haber–Bosch process is used in the Ostwald process to create nitric acid [11].
It has been estimated that the Haber–Bosch process consumes 1 to 2% of the world’s annual energy output [12]. The high energy consumption associated with fertilizer production results in large amounts of carbon dioxide and other greenhouse gases, such as nitrogen oxides (e.g.,: nitrous oxide, ozone, and particulate matter (PM2.5) [15]. High nitrogen dioxide concentrations may exacerbate common viral infections and cause lung damage [15]. In 2019, it was estimated that nitrogen dioxide pollution causes 4.0 (range, 1.8–5.2) million new pediatric asthma cases annually, being equal to 13% (range, 6–16%) of the global asthma incidence [16]. It is also important to note that the total amount of carbon dioxide equivalents released into the atmosphere due to ammonia production is about 400 Mt/year, which corresponds to 1.5% of all greenhouse gas emissions [11].
Current approaches to manufacturing fertilizer precursors, such as ammonia and nitric acid, call for urgent and large-scale needs for environmentally sustainable alternatives [13]. Here, we provide a review of plasma-activated water (PAW) as a sustainable alternative to conventional nitrate fertilizers, and we focus on controlled environment agriculture (CEA). PAW can be produced by renewable energy without toxic emissions and carbon footprint [17]. Reactive nitrogen and oxygen species possess a wide range of physical properties of water, which grants PAW the ability to promote plant growth, break seed dormancy, and suppress pathogens while simultaneously enhancing plants’ natural defense mechanisms by activating key physiological pathways [18,19,20,21]. In addition to its agricultural benefits, PAW has the potential to create new job opportunities in this emerging sector, fostering innovation and economic growth. Furthermore, its localized production capability enhances fertilizer sovereignty, allowing small-scale and decentralized fertilizer production for controlled environments [17,18,21,22].
Figure 1 illustrates the flow and summarizes the industrial process of producing nitrogen fertilizers. The system uses water (A) and methane from a natural gas supply (B) into the steam methane reforming process (C) to generate hydrogen. Compressed air (D) is fed to the air separation unit (E), which produces nitrogen (fed to the Haber-Bosch process) and oxygen (fed to the Ostwald process). Nitrogen (from E) combines with hydrogen (from C) in the Haber-Bosch process facility (F) to synthesize ammonia, which is input to the Ostwald process (G) together with oxygen (from E) and air (from D). The Ostwald process oxidizes ammonia (from F) to nitric acid (H). Ammonia (from F) and nitric acid (H), along with other chemicals (dashed lines), serve as primary precursors for nitrogen fertilizers (I), which are applied to agricultural systems (K) primarily as nitrate, ammonium, and urea. These fertilizers are transported via ships, rail, and trucks (J). These processes consume large amounts of fossil energy and emit significant greenhouse gases, including CO2, CO, and NOx. As a result, nitrogen fertilizer production imposes considerable environmental impacts and contributes to energy dependency and supply chain vulnerabilities in agriculture.

2. Controlled Environment Agriculture

CEA encompasses growing systems that shield crops from ambient climatic conditions while allowing precise control, monitoring, and regulation of the cultivation area’s microclimate to enhance yield stability and productivity [23]. There are many types of CEA facilities, including greenhouses, rooftop gardens, retrofit container farms, and plant factories (i.e., single-stack and vertical farms). CEA conditions can be adjusted to optimize specific crops’ growing requirements via supplemental lighting (LEDs and high-pressure sodium lamps) and carbon dioxide enrichment, regulation of vapor pressure deficit, and time-specific temperature modulations [24]. While offering year-round indoor crop production with less water [25], shorter growing periods [26], reduced space [27], and higher yields [27,28], CEA technologies remain dependent on fossil fuel -based synthetic fertilizers. Significant growth is expected in global CEA markets to suppress rising food insecurity as arable land per capita decreases and extreme climate events threaten field crop production [29]. According to a recent market analysis report, the global CEA market size was valued at USD 38 billion in 2023 with a compound annual growth rate of 13.2% over the next 5 years [30]. In the U.S. alone, the number of CEA operations has grown by over 100% in the last 15 years [31]. Novel crop production in cannabis and other economically viable edible, ornamental, and pharmaceutical plant commodities will expand the industry and worldwide production. However, achieving this growth and meeting the United Nations Sustainable Development Goals (SDGs) will require producers to adopt more sustainable technologies over traditional practices, highlighting opportunities for sustainable fertilizer production [32]. The 2030 Agenda for Sustainable Development provides a global framework for achieving peace and prosperity, encompassing seventeen Sustainable Development Goals [33].
The use of PAW for controlled delivery of plasma-generated reactive oxidative species to soil, soilless, and hydroponic systems creates new avenues of research as it is applied to fertilization and irrigation [34]. As a potential cost-effective source of fertilizer, PAW can also be used in pH management [11,12,13,35]. Furthermore, it has the potential to optimize plant–microbe interactions, improve nutrient availability, regulate plant hormone activity, and increase plant resistance to both biotic and abiotic stressors [18,20,21,36].

3. Physicochemical Properties and Generation of PAW

PAW forms through non-thermal plasma, which dissociates air molecules to generate oxidized and reduced nitrogen species directly in water [26,34]. Non-thermal plasma, also known as cold plasma, results from high-voltage discharges ionizing a gas through electron–molecule collisions, with input gases including ambient air, oxygen, nitrogen, helium, argon, and gas mixtures (Figure 2A) [34]. Input gas composition, discharge/reactor structure, activation method, applied voltage, activation time, storage conditions, flow rate, and treatment time determine characteristics and quantities of active species present in PAW [17,37,38,39,40,41]. In PAW, oxygen species include atomic oxygen, singlet oxygen, superoxide anion, and ozone, and reactive nitrogen species include atomic nitrogen, nitric oxide, nitrate, nitrite, and peroxy-nitrite [40,41]. PAW can also contain nitric oxide, nitrite, nitrate, dinitrogen trioxide, dinitrogen pentoxide, and ammonia [17,32]. These nitrogen compounds are mobile and soluble in soil, facilitating uptake and serving as fertilizers [42]. Input gas composition, discharge/reactor structure, activation method, applied voltage, activation time, storage conditions, flow rate, and treatment time also drive PAW’s physicochemical properties, including pH, conductivity, oxidative–reductive potential, total dissolved solids, and resistivity [20]. PAW exhibits high oxidation–reduction potential, with hydrogen peroxide acting as both an oxidant and reductant [32,43].
Water molecules undergo reactions with primary species, including hydroxyl radicals, hydrogen atoms, oxygen atoms, nitrogen atoms, nitric oxide, and ions to generate secondary species, notably hydrogen peroxide, nitrogen oxides, ozone, nitrous acid, nitric acid, peroxy-nitrous acid, and ions essential for PAW applications [32,39].
Reactor designs for PAW production either submerge electrodes in water or generate plasma above the surface, offering innovative alternatives to conventional fertilizer production. During plasma generation, nitrite forms via nitrogen–oxygen reactions, while nitric oxide and nitrite undergo post-discharge oxidation to nitrates through reactions with ozone, hydroxyl radicals, superoxide, and hydrogen peroxide [35]. PAW characteristics depend on production parameters, including discharge/reactor structure, activation method, applied voltage, activation time, storage conditions, and the flow rate and composition of the working gas [17,37].
Plasma exposure modifies oxidation–reduction potential and conductivity [35] and lowers water’s pH until gradually stabilizing as a function of extended treatment time [32,43]. PAW enhances macroscopic water properties, with conductivity increasing to 100–500 mS/cm, serving as an indicator of reactive species and ion diffusion, which increases density [32,43]. Enhanced conductivity significantly reduces surface tension, promoting evaporation and heat dissipation [32]. Additionally, PAW decreases the contact angle, improving surface energy through hydrophilic functional groups, which enhance water uptake and seed germination [44].
Reactive species in PAW exhibit distinct lifetimes: hydroxyl radicals, superoxide radicals, and non-radical peroxy-nitrite degrade within microseconds to nanoseconds, ozone within minutes, hydrogen peroxide within hours, nitrite within hours to days, while nitrate within months [35,45]. PAW’s physicochemical properties evolve post-discharge as species interact [46]. While pH and conductivity remain stable, reactive species fluctuate with storage time and conditions [47,48]. Short-lived reactive nitrogen species, such as peroxy-nitrous acid, degrade rapidly due to homolysis and isomerization in PAW’s acidic environment [49]. In this environment, nitrites react with hydrogen ions and hydrogen peroxide to form nitrates and peroxy-nitrite, progressively reducing nitrite and hydrogen peroxide while increasing nitrate levels over time (Figure 2C) [50,51,52]. PAW with nitrite concentrations exceeding 10 mg NO2−/L experiences rapid nitrite decline within 30 days, whereas lower initial nitrite levels remain stable (Figure 2C) [46,53]. The mechanisms of nitrate degradation remain unclear; however, nitrate concentrations below 15 mg NO3−/L remain stable for 30 days, while initial concentrations exceeding 40 mg NO3−/L decline to below 20 mg NO3−/L within the same period [47,48,53].
Few studies have examined the effects of storage methods on PAW characteristics. Storing PAW at −80 °C retains nitrite and hydrogen peroxide for 30 days while maintaining antibacterial properties better than storage at −20 °C, 4 °C, or 25 °C [47]. Additionally, a copper surface or increased pH slows nitrite and hydrogen peroxide degradation [50,54]. Further research is needed to optimize storage conditions for preserving PAW’s physicochemical properties when immediate use is not feasible.

4. Techno-Commercial Analysis and Market Potential of PAW

As global nitrogen fertilizer demand grows, projections indicate that by 2050, ammonia production is expected to reach 220 million tons [13]. The compound annual growth rate for market volume is projected at 2.1% between 2020 and 2026, with the potential market value exceeding USD 495 billion [13,43]. Nitric acid production and demand are also anticipated to grow steadily in the coming years [13]. Ammonia represents one of the highest-volume chemicals globally, with a market size of 175 million tons and a market value of USD 67 billion, accounting for approximately 5% of the global chemical market [43]. Fertilizer production dominates its consumption, comprising 80% of ammonia used by volume and 40% of its market value [55]. Developed in 1903 as one of the first industrial nitrogen fixation methods, the Birkeland–Eyde process utilized plasma-based nitrogen oxide synthesis but was eventually overshadowed by the Haber–Bosch process [14,17]. However, the increasing availability of affordable renewable electricity has renewed interest in plasma-based nitrogen fixation [14,17]. In particular, atmospheric plasma is more cost-effective and requires less infrastructure than low-pressure systems, making it suitable for scaling [56]. For example, atmospheric pressure plasma can produce 35 mL of plasma-activated desalinated water in 15 min, compared to only 10 mL produced by thermal desalination in 2 h [56]. Atmospheric pressure plasma consumes 2140 kWh per cubic meter, which is 92.6% less energy than traditional desalination methods [56]. When atmospheric pressure plasma is powered by renewable energy sources like solar or wind, it creates a sustainable way to produce PAW [56,57]. Direct solar plasma could reduce reliance on grid electricity or energy storage, making it especially beneficial in regions with abundant seawater but limited freshwater, such as California, the Middle East, West Africa, and Australia.
Hence, PAW presents a cost-effective alternative to conventional nitrogen fertilizers by eliminating the reliance on fossil fuel-derived ammonia and nitric acid. The Haber–Bosch and Ostwald processes require large energy inputs, consuming around 6.1 EJ and contributing 1.4% of global greenhouse gas emissions [13,14,58]. In contrast, PAW production relies on air, water, and electricity, enabling the use of renewable energy sources (e.g., solar, wind, thermal, hydroelectric) to drive nitrogen fixation [14,59]. The capital expenditure for plasma-based NOx synthesis is approximately half to one-third that of the electrolysis-based Haber–Bosch process combined with the Ostwald process, particularly if plasma generator costs decrease from USD 0.98/W to USD 0.054/W [14]. While current plasma-based NOx synthesis processes operate at 2.4 MJ mol−1 N, achieving full competitiveness with conventional methods requires reducing this to ≤0.7 MJ mol−1 N [14]. Non-thermal plasma holds the potential to meet this target through optimized reactor designs and enhanced plasma chemistry [14].
Using data from 2021, electricity prices were around USD 21.80 MWh−1, and the estimated production cost of nitric acid via non-thermal plasma was USD 713.95–USD 970.10 per ton, compared to the conventional market price of USD 272.50–USD 381.50 per ton [14]. However, as renewable energy prices decline, potentially reaching USD 5.45–USD 10.90 MWh−1, non-thermal plasma-based nitrogen fixation could become cost-competitive [14]. While conventional processes struggle with high costs when scaled down, plasma-based NOx synthesis is more adaptable for decentralized or on-site fertilizer production, minimizing distribution, transportation, and storage costs, which can triple fertilizer costs [14,59]. This scalability makes non-thermal plasma an attractive solution for smallholder farmers, localized fertilizer production, and self-sufficient agricultural systems [55,60]. This shift could also drive new job opportunities in plasma reactor manufacturing, renewable energy integration, and PAW-based fertilizer distribution, stimulating local economies [61,62]. As fertilizer markets expand, there is renewed interest in alternative nitrogen fixation methods that reduce energy consumption and environmental impact. PAW, driven by renewable electricity and offering lower infrastructure costs, presents a timely opportunity for researchers and industry to develop efficient, decentralized systems aligned with sustainability goals.

5. PAW and Sustainable Agricultural Potential

PAW has multiple beneficial effects on plants, including: enhancing seed germination (Figure 3A and Figure 4A) [20,63], promoting seedling and plant growth (Figure 3B and Figure 4B) [18,19,21], increasing abiotic stress tolerance [21,32], improving yield quality and quantity [20,23,24,25] (Figure 3C), decontaminating seeds and soil from pathogens (Figure 5A) [20,45,64,65,66], enhancing natural plant defenses [36] (Figure 5B), and boosting fertilizer (nitrate, ammonium) (Figure 5C, Table 2) [7,46,65].
PAW has been shown to enhance germination and seedling growth of black gram (Vigna mungo), radish sprouts (Raphanus sativus), soybeans (Glycine max), Zinnia (Zinnia elegans), Chinese cabbage (Brassica rapa subsp. pekinensis), lentils (Lens culinaris), tomato (Solanum lycopersicum), and rapeseed (Brassica napus) [19,32]. PAW-treated wheat (Triticum aestivum) and alfalfa (Medicago sativa) seeds exhibited increased drought resilience, germination, seedling growth, and root and shoot elongation [32]. PAW irrigation enhances nitrogen content and uptake of macroelements (Calcium, Phosphorus, Sodium, Potassium, Magnesium) and microelements (Manganese, Iron, Zinc) in tomato (Solanum lycopersicum) and wheat [37,67]. PAW boosts growth and yield by increasing chlorophyll content and seedling development. Treated wheat, peanuts (Arachis hypogaea), and brown rice seeds show improved germination, root and shoot growth, leaf expansion, and higher yields [32].
Reactive oxygen and nitrogen species regulate phytohormone levels, triggering metabolism that influences seed germination [68]. Hydrogen peroxide (H2O2) in PAW functions as a signaling molecule, activating OXI1 kinases, inducing callose production, triggering MAPK cascades, and stimulating phytohormones, such as salicylic and jasmonic acid, which are key hormonal regulators of plant defenses. Optimal hydrogen peroxide levels suppress early-stage two-spotted spider mite development and reduce their survival. PAW irrigation combined with plasma-treated rice seeds alters plant traits, negatively affecting fall armyworms (Spodoptera frugiperda) by reducing larval mass, delaying pupation, and increasing mortality by 25% [69]. Given these data, PAW irrigation should be explored as a sustainable pest management tool. Recent studies on entomopathogenic nematodes reveal PAW is harmless to Steinernema carpocapsae but lethal to Heterorhabditis bacteriophora and Steinernema feltiae at exposures ≥5 and 10 s, respectively [70]. Therefore, species-specific evaluations are necessary to prevent the disruption of soil-based biological control agents. In addition, PAW stimulates the synthesis of plant hormones, such as auxin and cytokinin, inducing physiological and biochemical changes that promote seed germination and plant growth [32,42,65].
Reactive oxygen and nitrogen species regulate phytohormone levels, triggering metabolism that influences seed germination [68]. Seed dormancy and germination depend on gibberellic acid and abscisic acid [71,72,73]. Gibberellic acid promotes germination by activating α-amylase, which remobilizes energy substrates, while abscisic acid maintains dormancy. Reactive oxygen and nitrogen species promote germination by degrading abscisic acid and enhancing gibberellic acid biosynthesis (Figure 4A) [74]. PAW enhances dormancy release through hormonal modulation, increased seed coat permeability, and enhanced water uptake [75]. Moderate reactive oxygen species levels act as signaling molecules for germination, while excessive levels cause oxidative stress. Reactive nitrogen species support plant nutrition and redox regulation, aiding the synthesis of amino acids, proteins, and chlorophyll (Figure 4B) [68]. The germination process involves three stages: water absorption, metabolic activation, and radicle protrusion. Reactive oxygen species trigger transduction events related to seed germination, while reactive nitrogen species regulate redox status and synthesis of biomolecules [34].
PAW has also been shown to suppress phytopathogenic bacteria, fungi, and arthropods, though research remains in the early stages (Figure 5A). It exhibits strong bactericidal effects against Bacillus cereus, Salmonella spp., and Escherichia coli on cherry tomatoes [76]. PAW application 1–24 h before pathogen inoculation reduces tomato leaf spot (Xanthomonas vesicatoria) severity by 61% [64]. It also inhibits Staphylococcus aureus on kiwifruit (Actinidia deliciosa) [77] and strawberries (Fragaria × ananassa) [78] and Escherichia coli on soybean (Glycine max) seeds [78]. PAW exhibits fungicidal effects, inhibiting spore germination and reducing Fusarium graminearum pathogenicity in wheat and barley (Hordeum vulgare) through cell wall disruption, increased membrane permeability, and mitochondrial dysfunction [20]. While PAW’s virucidal activity against plant viruses remains unconfirmed, related plasma technologies disrupt Tobacco mosaic virus particles and degrade RNA, reducing infectivity [79]. PAW elicited 90% mortality of mealybugs (Planococcus citri) within 24 h [80]. Direct treatment with atmospheric plasma discharge correlated with increased mortality of western flower thrips (Frankliniella occidentalis), tobacco thrips (Frankliniella fusca), Asian tiger mosquitoes (Aedes albopictus), two-spotted spider mites (Tetranychus urticae), and German cockroaches (Blattella germanica) [81]. Supplementary PAW irrigation of tomato plants induced avoidance behavior by two-spotted spider mites and reduced their population growth [36]. The authors demonstrated that both avoidance behavior and reduced population growth were likely associated with significant increases in densities of glandular and non-glandular trichomes. Non-glandular trichomes act as physical barriers, while glandular trichomes deter herbivores through allelochemical secretions such as acyl sugars, methyl ketones, and sesquiterpenes (Figure 5B) [36,82].

6. Expanding PAW’s Utility

The unique physicochemical properties of PAW have attracted growing attention in academic and industrial communities [66]. Beyond agricultural applications, PAW can be employed as a disinfectant and decontaminant due to the effects of reactive species on microorganisms such as planktonic bacteria, biofilms, molds, fungi, and viruses [83]. PAW has been found to be an effective inactivation technique for thirteen species of planktonic bacteria [68]. Additionally, PAW is effective at inactivating fungal spores as well as damaging viral DNA and RNA [68].
In the food industry, studies have demonstrated PAW’s effectiveness in extending the shelf life of various food products, including meat, fish, fruits, vegetables, and cereals, though its efficacy varies depending on treatment conditions and types of food [84]. PAW has also been investigated for processed foods, like bean curd and rice cakes, showing minimal changes to food quality while effectively reducing microbial load [69].
In the medical field, the acidity of PAW, along with the reactive oxygen and nitrogen species generated, is key for bacterial inactivation presenting PAW as a medium for device sterilization [85]. PAW also shows significant potential in dentistry due to its antimicrobial properties, making it suitable for decontaminating dental devices and treating oral infectious diseases, as well as promoting wound healing and reducing inflammation in infected lesions [63]. PAW’s reactive species could be utilized for tooth bleaching, offering a dual benefit of disinfection and esthetic improvement [63]. However, further in vivo studies and research are needed to confirm and optimize efficacy and safety within individual industries and among specific applications.

7. PAW Alignment with UN SDGs

The Sustainable Development Goals establish a roadmap for advancing innovation, agriculture, and climate resilience, aiming to tackle pressing global issues such as food insecurity, ecosystem loss, and environmental degradation by 2030 [33]. PAW contributes to SDG 2: Zero Hunger by enhancing seed germination, improving plant health, and increasing crop yields, directly supporting food security [33,61]. With 735 million people facing hunger in 2022, an increase of 122 million since 2019, innovative agricultural technologies like PAW are essential [62]. PAW also aligns with SDG 3: Good Health and Well-being by reducing chemical contamination in food production and enhancing food safety through its antimicrobial properties [62].
PAW supports SDG 7: Affordable and Clean Energy as it relies on electricity, which can be sourced from renewables, decreasing fossil fuel dependence [33,61]. Additionally, PAW enables localized, on-site fertilizer production using carbon-free methods at low temperatures and pressures, reducing reliance on centralized supply chains [17]. Integrating PAW with renewable energy could enhance agricultural self-sufficiency while advancing multiple SDGs.
In line with SDG 8: Decent Work and Economic Growth, PAW promotes sustainable agricultural practices that boost productivity while reducing chemical dependency, fostering economic resilience [61]. With over 2 billion workers in informal employment and global unemployment projected to rise in 2024, modernizing agriculture through PAW can create stable economic opportunities [62].
PAW advances SDG 9: Industry, Innovation, and Infrastructure by offering scalable technology for sustainable agriculture and food processing [33,61]. It also supports SDG 12: Responsible Consumption and Production by minimizing chemical fertilizer and pesticide use, reducing environmental contamination [33,62]. Given that 1.05 billion tons of food were wasted in 2022, PAW’s role in improving crop resilience and storage efficacy is crucial for reducing food losses [62]. Furthermore, PAW’s ability to enhance drought resilience and reduce water consumption in irrigation systems aligns with SDG 12. Small-scale, on-site fertilizer production powered by renewables could shift global fertilizer production dynamics, reducing import dependence and increasing energy independence in developing nations [22,60].
PAW contributes to SDG 14: Life Below Water and SDG 15: Life on Land by decreasing synthetic fertilizer and pesticide runoff, which harms aquatic and terrestrial ecosystems [33,62]. With ocean acidification rising and carbon dioxide levels now 150% above pre-industrial levels, alongside a 12% increase in species extinction risk since 1993, sustainable alternatives like PAW are essential [62]. Additionally, PAW supports SDG 13: Climate Action by lowering greenhouse gas emissions linked to chemical fertilizer and pesticide production and application [33,62]. With global carbon dioxide emissions at record highs and public fossil fuel funding tripling since 2015, sustainable agricultural solutions are urgent [62]. By improving soil health, reducing runoff, and cutting agriculture’s carbon footprint, PAW indirectly supports SDGs 14 and 15.
Finally, PAW aligns with SDG 17: Partnerships for the Goals by fostering collaboration among industry, universities, research centers, and governments. Strengthening these partnerships will be key to advancing PAW research and ensuring its full potential for sustainable impact is realized.

8. PAW Future Directions

PAW research faces key challenges that must be addressed for widespread agricultural adoption, including (1) methodological standardization [86], (2) mechanistic understanding [20], (3) scalability [13], and (4) regulatory acceptance. Overcoming these barriers is essential for optimizing PAW across diverse crops and controlled environments.
A current lack of standardized methodologies limits reproducibility and cross-study comparisons [20,86]. Variability in PAW generation, treatment, and storage requires standardized protocols for chemical characterization and meta-analyses. Most mechanistic studies focus on long-lived reactive species like nitrates and nitrites, while short-lived reactive species remain underexplored [86]. Expanding research on these compounds could improve understanding of PAW’s interactions with plant tissues and soil microbiomes. Additionally, while PAW’s impact on seed germination and plant growth is well studied, its potential in disease and pest management remains largely unexamined [87]. Investigating these applications could significantly enhance PAW’s utility as a sustainable alternative to conventional agrochemicals.
Scalability and economic viability must be assessed for PAW’s transition to commercial agriculture [19]. Pilot trials in commercial nurseries should evaluate their performance across crops, soil types, and greenhouse conditions [34,86]. Optimizing treatment intensity, frequency, and application methods can maximize agronomic benefits while minimizing energy consumption. Research should focus on energy-efficient PAW generation and integrating renewable energy sources to lower costs [13,17,88].
Adoption of PAW requires collaboration among researchers, industry, and policymakers [32]. Partnerships with agricultural supply companies and farmers can facilitate real-world implementation. Addressing publication bias is also crucial, as selective reporting skews perceived efficacy [18]. Transparent data reporting and parametric studies can improve reliability and reproducibility. Regulatory barriers hinder PAW’s adoption, particularly in organic farming. While legally recognized as a fertilizer in the EU, U.S., and Canada, its classification as an organic input is restricted [89]. EU Regulation 2018/848 prohibits highly soluble nitrogen fertilizers in organic systems, disqualifying PAW despite its on-site production potential. Advocacy should highlight PAW’s environmental benefits beyond nitrogen solubility to reconsider its eligibility. U.S. organic certifiers do not evaluate the equipment used to produce PAW, which allows on-site production. However, if PAW is commercialized as a fertilizer product, it would likely be classified as synthetic and is currently not eligible for use in organic agriculture due to the absence of a specific exemption [90,91]. Future efforts should aim to reclassify PAW as a non-synthetic input or establish a regulatory pathway for its acceptance as a sustainable synthetic alternative.
Research should evaluate PAW’s effects on soil health, nutrient leaching, and microbial dynamics. Generating robust sustainability data could support its inclusion in organic farming and broader agricultural policies.

9. Conclusions

PAW represents a transformative step toward sustainable nitrogen fertilization, addressing key environmental and economic challenges associated with conventional fertilizer production. Its ability to enhance plant growth, improve soil health, and minimize ecological impact positions PAW as a viable alternative for controlled environment agriculture. PAW’s impacts extend past plant nutrition to include economic decentralization of fertilizer production, reduced dependency on fossil fuel, and enhanced food sovereignty. However, its viability as a large-scale solution remains contingent on optimizing nitrogen yield, improving energy efficiency, and establishing standardized production protocols. This review underscores the necessity of further research into PAW’s reactive species effects over time, renewable energy integration, and cost-effectiveness compared to conventional fertilizers. By addressing these challenges, PAW could serve as a transformative technology that redefines nitrogen fertilization by supporting UN Sustainable Development Goals, mitigating climate impacts, and fostering a climate-conscious future through resilient global food systems.

Author Contributions

Conceptualization, C.N. and P.E.A.; writing—original draft preparation, C.N. and P.E.A.; writing—review and editing, C.N., P.E.A., P.J.S., B.A.C., F.S.A., A.P., Y.Z., N.E., G.A. and N.M.; illustrations, P.E.A. and P.J.S.; supervision, C.N. All authors have read and agreed to the published version of the manuscript.

Funding

This research was partially funded by the USDA/ARS Floriculture, Nursery Research Initiative, the American Floral Endowment, the USDA/Specialty Crop Multi-State Program (grant #21-0732-001-SF), Western Sustainable Agriculture Research and Education (WSARE Project #SW24-012), and the NIFA/Organic Agriculture Program (grant #2023-04746).

Data Availability Statement

No new data were created or analyzed in this study. Data sharing is not applicable to this article.

Acknowledgments

The authors wish to thank two anonymous reviewers for highly constructive and detailed revisions. Additionally, the authors are thankful to Erik Hertel for providing valuable insights into the regulatory landscape surrounding plasma-activated water and its classification as a fertilizer in the EU and the U.S.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
PAWPlasma-Activated Water
CEAControlled Environment Agriculture
LEDsLight-emitting diodes
PM2.5Particulate matter
UVUltraviolet
UNUnited Nations
SDGSustainable Development Goals
EUEuropean Union
U.S.United States of America
DNADeoxyribonucleic Acid
RNARibonucleic Acid

References

  1. Graham, F. Daily Briefing: World Population Estimated to Reach Eight Billion Today. Nature 2022, d41586-022-03739–9. [Google Scholar] [CrossRef] [PubMed]
  2. Tomšík, K.; Bartoňová, K.; Marušiak, J.; Čermák, M.; Blažek, V.; Malec, K.; Maitah, M. Global Trends in Fertilizer Commerce: A Dual Analysis of General and Nitrogen Fertilizer Markets; Maci, J., Maresova, P., Firlej, K., Soukal, I., Eds.; University of Hradec Králové: Hradec Králové, Czech Republic, 2024; pp. 442–452. [Google Scholar]
  3. Willer, H.; Trávníček, J.; Schlatter, B. The World of Organic Agriculture: Statistics & Emerging Trends 2024, 25th ed.; Research Institute of Organic Agriculture FiBL and IFOAM—Organics International: Frick/Bonn, Germany, 2024. [Google Scholar]
  4. U.S. Department of Agriculture, Economic Research Service. Food Availability (Per Capita) Data System: Vegetables (All Uses); Food Availability Data System; U.S. Department of Agriculture, Economic Research Service: Washington, DC, USA, 2024; p. 40. [Google Scholar]
  5. Gülüt, K.Y.; Şentürk, G.G. Impact of Nitrogen Fertilizer Type and Application Rate on Growth, Nitrate Accumulation, and Postharvest Quality of Spinach. PeerJ 2024, 12, e17726. [Google Scholar] [CrossRef] [PubMed]
  6. Rodríguez, A.; Peña-Fleitas, M.T.; Gallardo, M.; De Souza, R.; Padilla, F.M.; Thompson, R.B. Sweet Pepper and Nitrogen Supply in Greenhouse Production: Critical Nitrogen Curve, Agronomic Responses and Risk of Nitrogen Loss. Eur. J. Agron. 2020, 117, 126046. [Google Scholar] [CrossRef]
  7. Yue, W.; Liu, L.; Chen, S.; Bai, Y.; Li, N. Effects of Water and Nitrogen Coupling on Growth, Yield and Quality of Greenhouse Tomato. Water 2022, 14, 3665. [Google Scholar] [CrossRef]
  8. Him, R.; Romdhane, L.; Nicoletto, C.; Tlili, I.; Ilahy, R. Changes in Morphological and Physiological Parameters Affecting Lettuce Cultivars Due to Nitrogen Fertilizer in Greenhouse Tunnel. J. Postharvest Technol. 2024, 10, 19–34. [Google Scholar]
  9. Kosson, R.; Felczyński, K.; Szwejda-Grzybowska, J.; Grzegorzewska, M.; Tuccio, L.; Agati, G.; Kaniszewski, S. Nutritive Value of Marketable Heads and Outer Leaves of White Head Cabbage Cultivated at Different Nitrogen Rates. Acta Agric. Scand. Sect. B—Soil Plant Sci. 2017, 67, 524–533. [Google Scholar] [CrossRef]
  10. Yoder, N.; Davis, J.G. Organic Fertilizer Comparison on Growth and Nutrient Content of Three Kale Cultivars. HortTechnology 2020, 30, 176–184. [Google Scholar] [CrossRef]
  11. López Martínez, P. Techno-Economic Analysis of a Solar Ammonia and Fertilizer Production. Master’s Thesis, German Aerospace Center, Institute of Future Fuels, Linder Höhe, 51147, Cologne Germany DTU, Process and Systems Engineering Centre, Søltofts Plads, Building 224, 2800 Kgs, Lyngby, Denmark, 2022. [Google Scholar]
  12. Chen, J.G.; Crooks, R.M.; Seefeldt, L.C.; Bren, K.L.; Bullock, R.M.; Darensbourg, M.Y.; Holland, P.L.; Hoffman, B.; Janik, M.J.; Jones, A.K.; et al. Beyond Fossil Fuel–Driven Nitrogen Transformations. Science 2018, 360, eaar6611. [Google Scholar] [CrossRef]
  13. Lim, J.; Fernández, C.A.; Lee, S.W.; Hatzell, M.C. Ammonia and Nitric Acid Demands for Fertilizer Use in 2050. ACS Energy Lett. 2021, 6, 3676–3685. [Google Scholar] [CrossRef]
  14. Rouwenhorst, K.H.R.; Jardali, F.; Bogaerts, A.; Lefferts, L. From the Birkeland–Eyde Process towards Energy-Efficient Plasma-Based NOX Synthesis: A Techno-Economic Analysis. Energy Environ. Sci. 2021, 14, 2520–2534. [Google Scholar] [CrossRef]
  15. De Vries, W. Impacts of Nitrogen Emissions on Ecosystems and Human Health: A Mini Review. Curr. Opin. Environ. Sci. Health 2021, 21, 100249. [Google Scholar] [CrossRef]
  16. Achakulwisut, P.; Brauer, M.; Hystad, P.; Anenberg, S.C. Global, National, and Urban Burdens of Paediatric Asthma Incidence Attributable to Ambient NO2 Pollution: Estimates from Global Datasets. Lancet Planet. Health 2019, 3, e166–e178. [Google Scholar] [CrossRef] [PubMed]
  17. Peng, P.; Chen, P.; Schiappacasse, C.; Zhou, N.; Anderson, E.; Chen, D.; Liu, J.; Cheng, Y.; Hatzenbeller, R.; Addy, M.; et al. A Review on the Non-Thermal Plasma-Assisted Ammonia Synthesis Technologies. J. Clean. Prod. 2018, 177, 597–609. [Google Scholar] [CrossRef]
  18. Waskow, A.; Howling, A.; Furno, I. Mechanisms of Plasma-Seed Treatments as a Potential Seed Processing Technology. Front. Phys. 2021, 9, 617345. [Google Scholar] [CrossRef]
  19. Attri, P.; Ishikawa, K.; Okumura, T.; Koga, K.; Shiratani, M. Plasma Agriculture from Laboratory to Farm: A Review. Processes 2020, 8, 1002. [Google Scholar] [CrossRef]
  20. Guo, D.; Liu, H.; Zhou, L.; Xie, J.; He, C. Plasma-activated Water Production and Its Application in Agriculture. J. Sci. Food Agric. 2021, 101, 4891–4899. [Google Scholar] [CrossRef]
  21. Song, J.-S.; Kim, S.B.; Ryu, S.; Oh, J.; Kim, D.-S. Emerging Plasma Technology That Alleviates Crop Stress During the Early Growth Stages of Plants: A Review. Front. Plant Sci. 2020, 11, 988. [Google Scholar] [CrossRef]
  22. Ibendahl, G. The Russia-Ukraine Conflict and the Effect on Fertilizer; Department of Agricultural Economics, Kansas State University: Manhattan, KS, USA, 2022; pp. 1–12. [Google Scholar]
  23. Vatistas, C.; Avgoustaki, D.D.; Bartzanas, T. A Systematic Literature Review on Controlled-Environment Agriculture: How Vertical Farms and Greenhouses Can Influence the Sustainability and Footprint of Urban Microclimate with Local Food Production. Atmosphere 2022, 13, 1258. [Google Scholar] [CrossRef]
  24. Gómez, C.; Currey, C.J.; Dickson, R.W.; Kim, H.-J.; Hernández, R.; Sabeh, N.C.; Raudales, R.E.; Brumfield, R.G.; Laury-Shaw, A.; Wilke, A.K.; et al. Controlled Environment Food Production for Urban Agriculture. HortScience 2019, 54, 1448–1458. [Google Scholar] [CrossRef]
  25. Badji, A.; Benseddik, A.; Bensaha, H.; Boukhelifa, A.; Hasrane, I. Design, Technology, and Management of Greenhouse: A Review. J. Clean. Prod. 2022, 373, 133753. [Google Scholar] [CrossRef]
  26. Oh, S.; Lu, C. Vertical Farming—Smart Urban Agriculture for Enhancing Resilience and Sustainability in Food Security. J. Hortic. Sci. Biotechnol. 2023, 98, 133–140. [Google Scholar] [CrossRef]
  27. Ojo, M.O.; Zahid, A. Deep Learning in Controlled Environment Agriculture: A Review of Recent Advancements, Challenges and Prospects. Sensors 2022, 22, 7965. [Google Scholar] [CrossRef] [PubMed]
  28. Ragaveena, S.; Edward, A.S.; Surendran, U. Correction to: Smart Controlled Environment Agriculture Methods: A Holistic Review. Rev. Environ. Sci. Biotechnol. 2021, 20, 915. [Google Scholar] [CrossRef]
  29. Sharma, A.; Hazarika, M.; Heisnam, P.; Pandey, H.; Devadas, V.S.; Wangsu, M. Controlled Environment Ecosystem: A Plant Growth System to Combat Climate Change through Soilless Culture. Crop Des. 2024, 3, 100044. [Google Scholar] [CrossRef]
  30. Grand View Research. Indoor Farming Market Size, Share, Growth Report, 2030; Grand View Research: San Francisco, CA, USA, 2024; p. 120. [Google Scholar]
  31. Dohlman, E.; Maguire, K.; Davis, W.; Husby, M.; Bovay, J.; Weber, C.; Lee, Y. Trends, Insights, and Future Prospects for Production in Controlled Environment Agriculture and Agrivoltaics Systems; U.S. Department of Agriculture, Economic Research Service: Washington, DC, USA, 2024; p. 48. [Google Scholar]
  32. Pańka, D.; Jeske, M.; Łukanowski, A.; Baturo-Cieśniewska, A.; Prus, P.; Maitah, M.; Maitah, K.; Malec, K.; Rymarz, D.; Muhire, J.D.D.; et al. Can Cold Plasma Be Used for Boosting Plant Growth and Plant Protection in Sustainable Plant Production? Agronomy 2022, 12, 841. [Google Scholar] [CrossRef]
  33. Fernandes, F.A.N.; Rodrigues, S. Cold Plasma Technology for Sustainable Food Production: Meeting the United Nations Sustainable Development Goals. Sustain. Food Technol. 2025, 3, 32–53. [Google Scholar] [CrossRef]
  34. Ranieri, P.; Sponsel, N.; Kizer, J.; Rojas-Pierce, M.; Hernández, R.; Gatiboni, L.; Grunden, A.; Stapelmann, K. Plasma Agriculture: Review from the Perspective of the Plant and Its Ecosystem. Plasma Process. Polym. 2021, 18, 2000162. [Google Scholar] [CrossRef]
  35. Rossetti, I. Reactor Design, Modelling and Process Intensification for Ammonia Synthesis. In Sustainable Ammonia Production; Inamuddin, Boddula, R., Asiri, A., Eds.; Green Energy and Technology; Springer: Cham, Switzerland, 2020; pp. 17–48. [Google Scholar] [CrossRef]
  36. Savi, P.J.; Mantri, A.; Khodaverdi, H.; Zou, Y.; De Moraes, G.J.; Nansen, C. Indirect Effects of Plasma-Activated Water Irrigation on Tetranychus Urticae Populations. J. Pest Sci. 2025, 98, 449–462. [Google Scholar] [CrossRef]
  37. Laroque, D.A.; Seó, S.T.; Valencia, G.A.; Laurindo, J.B.; Carciofi, B.A.M. Cold Plasma in Food Processing: Design, Mechanisms, and Application. J. Food Eng. 2022, 312, 110748. [Google Scholar] [CrossRef]
  38. Rathore, V.; Nema, S.K. The Role of Different Plasma Forming Gases on Chemical Species Formed in Plasma Activated Water (PAW) and Their Effect on Its Properties. Phys. Scr. 2022, 97, 065003. [Google Scholar] [CrossRef]
  39. Zhou, R.; Zhou, R.; Wang, P.; Xian, Y.; Mai-Prochnow, A.; Lu, X.; Cullen, P.J.; Ostrikov, K.K.; Bazaka, K. Plasma-Activated Water: Generation, Origin of Reactive Species and Biological Applications. J. Phys. Appl. Phys. 2020, 53, 303001. [Google Scholar] [CrossRef]
  40. Jablonowski, H.; Schmidt-Bleker, A.; Weltmann, K.-D.; Von Woedtke, T.; Wende, K. Non-Touching Plasma–Liquid Interaction—Where Is Aqueous Nitric Oxide Generated? Phys. Chem. Chem. Phys. 2018, 20, 25387–25398. [Google Scholar] [CrossRef] [PubMed]
  41. Liu, K.; Liu, S.; Ran, C. The Effect of Air-Water-Plasma-Jet-Activated Water on Penicillium: The Reaction of HNO2 and H2O2 Under Acidic Condition. Front. Phys. 2020, 8, 242. [Google Scholar] [CrossRef]
  42. Domonkos, M.; Tichá, P.; Trejbal, J.; Demo, P. Applications of Cold Atmospheric Pressure Plasma Technology in Medicine, Agriculture and Food Industry. Appl. Sci. 2021, 11, 4809. [Google Scholar] [CrossRef]
  43. Mordor Intelligence Research & Advisory. Ammonia Market Size & Share Analysis—Growth Trends & Forecasts (2025–2030); Mordor Intelligence: Telangana, India, 2024. [Google Scholar]
  44. Mohajer, M.H.; Monfaredi, M.; Rahmani, M.; Martami, M.; Razaghiha, E.; Mirjalili, M.H.; Hamidi, A.; Ghomi, H.R. Impact of Dielectric Barrier Discharge Plasma and Plasma-Activated Water on Cotton Seed Germination and Seedling Growth. Heliyon 2024, 10, e38160. [Google Scholar] [CrossRef]
  45. Gao, Y.; Francis, K.; Zhang, X. Review on Formation of Cold Plasma Activated Water (PAW) and the Applications in Food and Agriculture. Food Res. Int. 2022, 157, 111246. [Google Scholar] [CrossRef]
  46. Bradu, C.; Kutasi, K.; Magureanu, M.; Puač, N.; Živković, S. Reactive Nitrogen Species in Plasma-Activated Water: Generation, Chemistry and Application in Agriculture. J. Phys. Appl. Phys. 2020, 53, 223001. [Google Scholar] [CrossRef]
  47. Shen, J.; Tian, Y.; Li, Y.; Ma, R.; Zhang, Q.; Zhang, J.; Fang, J. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water Stored at Different Temperatures. Sci. Rep. 2016, 6, 28505. [Google Scholar] [CrossRef]
  48. Vlad, I.-E.; Anghel, S.D. Time Stability of Water Activated by Different On-Liquid Atmospheric Pressure Plasmas. J. Electrost. 2017, 87, 284–292. [Google Scholar] [CrossRef]
  49. Goldstein, S.; Lind, J.; Merényi, G. Chemistry of Peroxynitrites as Compared to Peroxynitrates. Chem. Rev. 2005, 105, 2457–2470. [Google Scholar] [CrossRef]
  50. Kutasi, K.; Popović, D.; Krstulović, N.; Milošević, S. Tuning the Composition of Plasma-Activated Water by a Surface-Wave Microwave Discharge and a kHz Plasma Jet. Plasma Sources Sci. Technol. 2019, 28, 095010. [Google Scholar] [CrossRef]
  51. Ghorui, S.; Tiwari, N.; Parab, H. Atmospheric Pressure Portable Catalytic Thermal Plasma System for Fast Synthesis of Aqueous NO3 and NO2 Fertilizer from Air and Water. Plasma Chem. Plasma Process. 2025, 45, 371–402. [Google Scholar] [CrossRef]
  52. Jung, S.; Kim, H.J.; Park, S.; In Yong, H.; Choe, J.H.; Jeon, H.-J.; Choe, W.; Jo, C. The Use of Atmospheric Pressure Plasma-Treated Water as a Source of Nitrite for Emulsion-Type Sausage. Meat Sci. 2015, 108, 132–137. [Google Scholar] [CrossRef]
  53. Wang, Q.; Salvi, D. Evaluation of Plasma-Activated Water (PAW) as a Novel Disinfectant: Effectiveness on Escherichia Coli and Listeria Innocua, Physicochemical Properties, and Storage Stability. LWT 2021, 149, 111847. [Google Scholar] [CrossRef]
  54. Lukes, P.; Dolezalova, E.; Sisrova, I.; Clupek, M. Aqueous-Phase Chemistry and Bactericidal Effects from an Air Discharge Plasma in Contact with Water: Evidence for the Formation of Peroxynitrite through a Pseudo-Second-Order Post-Discharge Reaction of H2 O2 and HNO2. Plasma Sources Sci. Technol. 2014, 23, 015019. [Google Scholar] [CrossRef]
  55. Smith, C.; Hill, A.K.; Torrente-Murciano, L. Current and Future Role of Haber–Bosch Ammonia in a Carbon-Free Energy Landscape. Energy Environ. Sci. 2020, 13, 331–344. [Google Scholar] [CrossRef]
  56. Ekanayake, U.G.M.; Seo, D.H.; Faershteyn, K.; O’Mullane, A.P.; Shon, H.; MacLeod, J.; Golberg, D.; Ostrikov, K.K. Atmospheric-Pressure Plasma Seawater Desalination: Clean Energy, Agriculture, and Resource Recovery Nexus for a Blue Planet. Sustain. Mater. Technol. 2020, 25, e00181. [Google Scholar] [CrossRef]
  57. Khanmohammadi, S.; Khanjani, S. Experimental Study to Improve the Performance of Solar Still Desalination by Hydrophobic Condensation Surface Using Cold Plasma Technology. Sustain. Energy Technol. Assess. 2021, 45, 101129. [Google Scholar] [CrossRef]
  58. Capdevila-Cortada, M. Electrifying the Haber–Bosch. Nat. Catal. 2019, 2, 1055. [Google Scholar] [CrossRef]
  59. Winter, L.R.; Chen, J.G. N2 Fixation by Plasma-Activated Processes. Joule 2021, 5, 300–315. [Google Scholar] [CrossRef]
  60. Ben Hassen, T.; El Bilali, H. Impacts of the Russia-Ukraine War on Global Food Security: Towards More Sustainable and Resilient Food Systems? Foods 2022, 11, 2301. [Google Scholar] [CrossRef] [PubMed]
  61. United Nations. Transforming Our World: The 2030 Agenda for Sustainable Development; United Nations: New York, NY, USA, 2015. [Google Scholar]
  62. United Nations. Progress towards the Sustainable Development Goals; United Nations: New York, NY, USA, 2024; p. 26. [Google Scholar]
  63. Milhan, N.V.M.; Chiappim, W.; Sampaio, A.D.G.; Vegian, M.R.D.C.; Pessoa, R.S.; Koga-Ito, C.Y. Applications of Plasma-Activated Water in Dentistry: A Review. Int. J. Mol. Sci. 2022, 23, 4131. [Google Scholar] [CrossRef]
  64. Perez, S.M.; Biondi, E.; Laurita, R.; Proto, M.; Sarti, F.; Gherardi, M.; Bertaccini, A.; Colombo, V. Plasma Activated Water as Resistance Inducer against Bacterial Leaf Spot of Tomato. PLoS ONE 2019, 14, e0217788. [Google Scholar] [CrossRef]
  65. Pakprom, J.; Santalunai, S.; Charoensiri, W.; Ramjanthuk, S.; Janpangngern, P.; Thongsopa, C.; Thosdeekoraphat, T.; Santalunai, N.; Santalunai, S. Optimizing Nitrate Fertilizer Production Using Plasma-Activated Water (PAW) Technology: An Analysis of Dielectric Properties. Appl. Sci. 2024, 14, 9997. [Google Scholar] [CrossRef]
  66. Thirumdas, R.; Kothakota, A.; Annapure, U.; Siliveru, K.; Blundell, R.; Gatt, R.; Valdramidis, V.P. Plasma Activated Water (PAW): Chemistry, Physico-Chemical Properties, Applications in Food and Agriculture. Trends Food Sci. Technol. 2018, 77, 21–31. [Google Scholar] [CrossRef]
  67. Wang, J.; Cheng, J.-H.; Sun, D.-W. Enhancement of Wheat Seed Germination, Seedling Growth and Nutritional Properties of Wheat Plantlet Juice by Plasma Activated Water. J. Plant Growth Regul. 2023, 42, 2006–2022. [Google Scholar] [CrossRef]
  68. Wong, K.S.; Chew, N.S.L.; Low, M.; Tan, M.K. Plasma-Activated Water: Physicochemical Properties, Generation Techniques, and Applications. Processes 2023, 11, 2213. [Google Scholar] [CrossRef]
  69. Dilip, D.; Modupalli, N.; Rahman, M.M.; Kariyat, R. Atmospheric Cold Plasma Alters Plant Traits and Negatively Affects the Growth and Development of Fall Armyworm in Rice. Sci. Rep. 2025, 15, 3680. [Google Scholar] [CrossRef]
  70. Doshi, P.; Klas, M.; Kyzek, S.; Zahoranová, A.; Šerá, B. Investigating the Effect of Plasma Activated Water on Entomopathogenic Nematodes under Laboratory Conditions. Heliyon 2025, 11, e42038. [Google Scholar] [CrossRef]
  71. Kucera, B.; Cohn, M.A.; Leubner-Metzger, G. Plant Hormone Interactions during Seed Dormancy Release and Germination. Seed Sci. Res. 2005, 15, 281–307. [Google Scholar] [CrossRef]
  72. Tuan, P.A.; Kumar, R.; Rehal, P.K.; Toora, P.K.; Ayele, B.T. Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals. Front. Plant Sci. 2018, 9, 668. [Google Scholar] [CrossRef] [PubMed]
  73. Sharma, A.; Pandey, S.; Bhardwaj, R.; Zheng, B.; Tripathi, D.K. The Role of Growth Regulators and Phytohormones in Overcoming Environmental Stress; Elsevier: Amsterdam, The Netherlands, 2023; ISBN 978-0-323-98332-7. [Google Scholar]
  74. Barjasteh, A.; Lamichhane, P.; Dehghani, Z.; Kaushik, N.; Gupta, R.; Choi, E.H.; Kaushik, N.K. Recent Progress of Non-Thermal Atmospheric Pressure Plasma for Seed Germination and Plant Development: Current Scenario and Future Landscape. J. Plant Growth Regul. 2023, 42, 5417–5432. [Google Scholar] [CrossRef]
  75. Priatama, R.A.; Pervitasari, A.N.; Park, S.; Park, S.J.; Lee, Y.K. Current Advancements in the Molecular Mechanism of Plasma Treatment for Seed Germination and Plant Growth. Int. J. Mol. Sci. 2022, 23, 4609. [Google Scholar] [CrossRef]
  76. Lee, G.; Choi, S.-W.; Yoo, M.; Chang, H.-J.; Lee, N. Effects of Plasma-Activated Water Treatment on the Inactivation of Microorganisms Present on Cherry Tomatoes and in Used Wash Solution. Foods 2023, 12, 2461. [Google Scholar] [CrossRef]
  77. Zhao, Y.; Chen, R.; Liu, D.; Wang, W.; Niu, J.; Xia, Y.; Qi, Z.; Zhao, Z.; Song, Y. Effect of Nonthermal Plasma-Activated Water on Quality and Antioxidant Activity of Fresh-Cut Kiwifruit. IEEE Trans. Plasma Sci. 2019, 47, 4811–4817. [Google Scholar] [CrossRef]
  78. Ma, R.; Wang, G.; Tian, Y.; Wang, K.; Zhang, J.; Fang, J. Non-Thermal Plasma-Activated Water Inactivation of Food-Borne Pathogen on Fresh Produce. J. Hazard. Mater. 2015, 300, 643–651. [Google Scholar] [CrossRef]
  79. Hanbal, S.E.; Takashima, K.; Miyashita, S.; Ando, S.; Ito, K.; Elsharkawy, M.M.; Kaneko, T.; Takahashi, H. Atmospheric-Pressure Plasma Irradiation Can Disrupt Tobacco Mosaic Virus Particles and RNAs to Inactivate Their Infectivity. Arch. Virol. 2018, 163, 2835–2840. [Google Scholar] [CrossRef] [PubMed]
  80. Ten Bosch, L.; Köhler, R.; Ortmann, R.; Wieneke, S.; Viöl, W. Insecticidal Effects of Plasma Treated Water. Int. J. Environ. Res. Public. Health 2017, 14, 1460. [Google Scholar] [CrossRef]
  81. Donohue, K.V.; Bures, B.L.; Bourham, M.A.; Roe, R.M. Mode of Action of a Novel Nonchemical Method of Insect Control: Atmospheric Pressure Plasma Discharge. J. Econ. Entomol. 2006, 99, 38–47. [Google Scholar] [CrossRef]
  82. Lucini, T.; Faria, M.V.; Rohde, C.; Resende, J.T.V.; De Oliveira, J.R.F. Acylsugar and the Role of Trichomes in Tomato Genotypes Resistance to Tetranychus Urticae. Arthropod-Plant Interact. 2015, 9, 45–53. [Google Scholar] [CrossRef]
  83. Heng, Y.; Wang, M.; Jiang, H.; Gao, S.; Zhang, J.; Wan, J.; Song, T.; Ren, Z.; Zhu, Y. Plasma-Activated Acidic Electrolyzed Water: A New Food Disinfectant for Bacterial Suspension and Biofilm. Foods 2022, 11, 3241. [Google Scholar] [CrossRef] [PubMed]
  84. Rahman, M.; Hasan, M.S.; Islam, R.; Rana, R.; Sayem, A.; Sad, M.A.A.; Matin, A.; Raposo, A.; Zandonadi, R.P.; Han, H.; et al. Plasma-Activated Water for Food Safety and Quality: A Review of Recent Developments. Int. J. Environ. Res. Public Health 2022, 19, 6630. [Google Scholar] [CrossRef] [PubMed]
  85. Abuzairi, T.; Ramadhanty, S.; Puspohadiningrum, D.F.; Ratnasari, A.; Poespawati, N.R.; Purnamaningsih, R.W. Investigation on Physicochemical Properties of Plasma-Activated Water for the Application of Medical Device Sterilization; AIP Publishing: Bali, Indonesia, 2018; p. 040017. [Google Scholar]
  86. Waskow, A.; Avino, F.; Howling, A.; Furno, I. Entering the Plasma Agriculture Field: An Attempt to Standardize Protocols for Plasma Treatment of Seeds. Plasma Process. Polym. 2022, 19, 2100152. [Google Scholar] [CrossRef]
  87. Locatelli, S.; Triolone, S.; De Bonis, M.; Zanin, G.; Nicoletto, C. Non-Thermal Plasma-Activated Water Enhances Nursery Production of Vegetables: A Species-Specific Study. Agronomy 2025, 15, 209. [Google Scholar] [CrossRef]
  88. Punith, N.; Harsha, R.; Lakshminarayana, R.; Hemanth, M.; Anand, M.S.; Dasappa, S. Plasma Activated Water Generation and Its Application in Agriculture. Adv. Mater. Lett. 2019, 10, 700–704. [Google Scholar] [CrossRef]
  89. European Parliament; Council of the European Union. Regulation (EU) 2018/848 of the European Parliament and of the Council on Organic Production and Labelling of Organic Products; Official Journal of the European Union: Brussels, Belgium, 2018; pp. L 150/1–L 150/14. [Google Scholar]
  90. Agricultural Marketing Service; USDA. Synthetic Substances Allowed for Use in Organic Production; Code of Federal Regulations (CFR), Title 7, Part 205; Government Publishing Office: Washington, DC, USA, 2024; pp. 449–451. [Google Scholar]
  91. USDA; NOP; Agricultural Marketing Service. Decision Tree for Classification of Materials as Synthetic or Nonsynthetic; NOP Guidance Document (NOP 5033-1); USDA: Washington, DC, USA, 2016; pp. 1–3. [Google Scholar]
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Figure 1. Flowchart of conventional fossil-based nitrogen fertilizer production. (A) Water fed to the steam methane reforming process facility. (B) Methane fed to the steam methane reforming process facility. (C) Steam methane reforming processes facility. (D) Air from the air compressor unit fed to the air separation unit and to the Ostwald process. (E) Nitrogen fed to the Haber-Bosch process and oxygen fed to the Ostwald process from the air separation unit. (F) Haber-Bosch process facility feeding ammonia to the Ostwald process facility. (G) Ostwald process facility. (H) Nitric acid produced from the Ostwald process. (I) Nitrogen fertilizer produced with nitric acid and ammonia from the Haber-Bosch process along with other chemical processes. (J) Transportation of fertilizers via ships, rail, and trucks. (K) Final destination of nitrogen fertilizers (greenhouses). The arrow tips on the lines indicate the direction of flow and input to a process. The white circles at the end of lines represent an output from a process, indicating where the flow continues or exits the system. Dashed lines represent the combination of products with other chemical processes (e.g., ammonia and nitric acid combined with additional non-represented chemical processes to produce nitrogen fertilizer).
Figure 1. Flowchart of conventional fossil-based nitrogen fertilizer production. (A) Water fed to the steam methane reforming process facility. (B) Methane fed to the steam methane reforming process facility. (C) Steam methane reforming processes facility. (D) Air from the air compressor unit fed to the air separation unit and to the Ostwald process. (E) Nitrogen fed to the Haber-Bosch process and oxygen fed to the Ostwald process from the air separation unit. (F) Haber-Bosch process facility feeding ammonia to the Ostwald process facility. (G) Ostwald process facility. (H) Nitric acid produced from the Ostwald process. (I) Nitrogen fertilizer produced with nitric acid and ammonia from the Haber-Bosch process along with other chemical processes. (J) Transportation of fertilizers via ships, rail, and trucks. (K) Final destination of nitrogen fertilizers (greenhouses). The arrow tips on the lines indicate the direction of flow and input to a process. The white circles at the end of lines represent an output from a process, indicating where the flow continues or exits the system. Dashed lines represent the combination of products with other chemical processes (e.g., ammonia and nitric acid combined with additional non-represented chemical processes to produce nitrogen fertilizer).
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Figure 2. Formation of PAW components through jet plasma and post-discharge physicochemical changes during storage. (A) Electron–molecule collisions in the plasma beam, ambient air serves as the input gas. (B) Gas–liquid interface, where the plasma interacts with water, generating reactive oxygen and nitrogen species. (C) Physicochemical changes in three main components of PAW during storage.
Figure 2. Formation of PAW components through jet plasma and post-discharge physicochemical changes during storage. (A) Electron–molecule collisions in the plasma beam, ambient air serves as the input gas. (B) Gas–liquid interface, where the plasma interacts with water, generating reactive oxygen and nitrogen species. (C) Physicochemical changes in three main components of PAW during storage.
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Figure 3. Effect of PAW on tomato plant growth. (A) Seed germination differences between the control group and PAW-treated seeds. (B) Differences in seedling vigor, uniformity, and root growth between the control and PAW-treated groups. (C) Differences in plant growth, yield quantity and quality between the control and PAW-treated groups.
Figure 3. Effect of PAW on tomato plant growth. (A) Seed germination differences between the control group and PAW-treated seeds. (B) Differences in seedling vigor, uniformity, and root growth between the control and PAW-treated groups. (C) Differences in plant growth, yield quantity and quality between the control and PAW-treated groups.
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Figure 4. Mechanisms of PAW in seed germination and nitrogen assimilation (A) PAW-induced seed germination. PAW delivers reactive oxygen species (ROS) and reactive nitrogen species (RNS) like NO2− and NO3−. These species, exogenous factors, promote seed coat erosion and modulate endogenous hormonal pathways, stimulating gibberellic acid (GA) and inhibiting abscisic acid (ABA), alongside direct ROS involvement, to trigger germination (B) PAW-derived nitrogen uptake and assimilation. Plant roots readily absorb PAW-derived nitrogen species (NO3− and NH4+) via specific protein transporters in the plasma membrane. NO3− is reduced to NO2− and then to NH4+, which is subsequently incorporated into amino acids, primarily within plastids. Nitrogen can be stored in the vacuole as a nitrogen reserve or transported to the shoot, demonstrating efficient assimilation of PAW-provided nitrogen for plant growth.
Figure 4. Mechanisms of PAW in seed germination and nitrogen assimilation (A) PAW-induced seed germination. PAW delivers reactive oxygen species (ROS) and reactive nitrogen species (RNS) like NO2− and NO3−. These species, exogenous factors, promote seed coat erosion and modulate endogenous hormonal pathways, stimulating gibberellic acid (GA) and inhibiting abscisic acid (ABA), alongside direct ROS involvement, to trigger germination (B) PAW-derived nitrogen uptake and assimilation. Plant roots readily absorb PAW-derived nitrogen species (NO3− and NH4+) via specific protein transporters in the plasma membrane. NO3− is reduced to NO2− and then to NH4+, which is subsequently incorporated into amino acids, primarily within plastids. Nitrogen can be stored in the vacuole as a nitrogen reserve or transported to the shoot, demonstrating efficient assimilation of PAW-provided nitrogen for plant growth.
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Figure 5. Comparison of the benefits of PAW application in crop production. (A) Presence of pathogens in untreated plants. (B) Pest infestation in untreated plants, with a reduction in pest populations in PAW-treated plants, attributed to increased trichome density. (C) PAW as a fertilizer enhancer, promoting plant growth and overall health.
Figure 5. Comparison of the benefits of PAW application in crop production. (A) Presence of pathogens in untreated plants. (B) Pest infestation in untreated plants, with a reduction in pest populations in PAW-treated plants, attributed to increased trichome density. (C) PAW as a fertilizer enhancer, promoting plant growth and overall health.
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Table 1. Vegetable production and consumption data.
Table 1. Vegetable production and consumption data.
CropsRecommended N Fertilization (kg N ha−1)Average Yield (Mg ha−1)Annual Consumption per Capita (kg/Person)References
Spinach 50–15032–50 1.30 [4,5]
Bell Pepper425 935.02 [4,6]
Tomato320 53–94 34.25 [4,7]
Lettuce
(Romain, butterhead, iceberg)		80275.76[4,8]
Cabbage (White head)200–50096–1973.24[4,9]
Kale112 10–15 0.44[4,10]
Table 2. Comparison between PAW and conventional nitrogen fertilizers on key germination and growth-related metrics in crops.
Table 2. Comparison between PAW and conventional nitrogen fertilizers on key germination and growth-related metrics in crops.
MetricsPAWConventional Fertilizers
Seed germination rateEnhanced in various speciesIndirect effect; not formulated to enhance germination
Seedling vigor and uniformityImproved vigor, uniformity, and root developmentNo direct impact on uniformity or vigor
Root and shoot growthIncreased elongation and biomass in various speciesSupports growth via nutrient supply but may not enhance morphology
Chlorophyll contentElevated chlorophyll contentDependent on nitrate uptake; not always optimized
Yield quantity and qualityImproved fruit size, weight, and overall qualityImproves yield quantity, less consistent effect on quality
Abiotic stress toleranceIncreased tolerance to drought and salinityLimited or no stress-mitigating properties
Nutrient uptake efficiencyEnhanced uptake of multiple nutrientsSupplies nutrients but may not optimize uptake
Hormonal modulationActivates auxins, cytokinins, and gibberellins for growth and germinationNo direct hormonal interaction
Pest resistance Induces trichome development, reducing pest populationsNo effect on physical pest defenses
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Andrade, P.E.; Savi, P.J.; Almeida, F.S.; Carciofi, B.A.; Pace, A.; Zou, Y.; Eylands, N.; Annor, G.; Mattson, N.; Nansen, C. Plasma-Activated Water as a Sustainable Nitrogen Source: Supporting the UN Sustainable Development Goals (SDGs) in Controlled Environment Agriculture. Crops 2025, 5, 35. https://doi.org/10.3390/crops5030035

AMA Style

Andrade PE, Savi PJ, Almeida FS, Carciofi BA, Pace A, Zou Y, Eylands N, Annor G, Mattson N, Nansen C. Plasma-Activated Water as a Sustainable Nitrogen Source: Supporting the UN Sustainable Development Goals (SDGs) in Controlled Environment Agriculture. Crops. 2025; 5(3):35. https://doi.org/10.3390/crops5030035

Chicago/Turabian Style

Andrade, Pamela Estefania, Patrice Jacob Savi, Flavia Souza Almeida, Bruno Augusto Carciofi, Abby Pace, Yugeng Zou, Nathan Eylands, George Annor, Neil Mattson, and Christian Nansen. 2025. "Plasma-Activated Water as a Sustainable Nitrogen Source: Supporting the UN Sustainable Development Goals (SDGs) in Controlled Environment Agriculture" Crops 5, no. 3: 35. https://doi.org/10.3390/crops5030035

APA Style

Andrade, P. E., Savi, P. J., Almeida, F. S., Carciofi, B. A., Pace, A., Zou, Y., Eylands, N., Annor, G., Mattson, N., & Nansen, C. (2025). Plasma-Activated Water as a Sustainable Nitrogen Source: Supporting the UN Sustainable Development Goals (SDGs) in Controlled Environment Agriculture. Crops, 5(3), 35. https://doi.org/10.3390/crops5030035

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