Iron Fertilization Research Articles

Assessment of a commercial biodegradable iron fertilizer (Fe3+-IDS) for water treatment by solar photo-Fenton at near-neutral pH

The employ of commercial iron fertilizers based on aminopolycarboxylic chelates for urban wastewater reclamation stands out as a practical circular economy approach for arid/semi-arid regions. A proof-of-principle study of a novel photo-Fenton-like process using the commercial fertilizer ADOB® Fe IDHA-9% based on Fe3+-IDS (Fe3+-IDS/H2O2/solar) for organic pollutant removal has been performed. The process was tested including the baseline effects of photolysis, H2O2/solar, Fe3+-IDS/solar and Fe3+-IDS/H2O2, in a wide range of target pollutants (0.1–10 mg/L) and reagent concentrations (1–10 and 4–40 mg/L of Fe3+-IDS and H2O2, respectively), in three water matrices (demineralized, natural water and synthetic urban wastewater) and at lab-scale under constant artificial solar radiation. Successful removal of 10 mg/L of imidacloprid (85% in 60 min), was attained by the photo-Fenton-like process with a significant contribution of the Fenton process (52%) and photo-redox activation of the iron chelate (37%). The increase of the water matrix complexity, mainly in bicarbonate ions and organic matter content, leads to a moderate performance decrease (66% removal in 60 min). When increasing the complexity of the water matrix to synthetic urban wastewater, high process performance was attained in 60 min to remove three recalcitrant contaminants of emerging concern: 63%, 81% and 92% for imidacloprid, carbamazepine and trimethoprim, respectively. The results obtained showed a high efficiency of the use of a commercial fertilizer based on iron in the photo-Fenton process, slightly lower than the widely studied Fe-EDDS, but feasible to be an alternative iron source for solar photo-Fenton at near-neutral pH based on its lower cost and environmentally greener characteristics.

Assessing microbially mediated vivianite as a novel phosphorus and iron fertilizer

BackgroundMicroorganisms can transform phosphorus (P)-enriched iron (Fe)-oxide sludge into products with higher P concentration or can directly promote the precipitation of P-rich compounds from water. However, there is no evidence of these products’ efficiency as fertilizers. This study aimed to assess the effectiveness of microbially mediated vivianite (biovivianite) as P and Fe fertilizer for durum wheat and white lupin, respectively.ResultsTo this end, two completely randomized block experiments were conducted with wheat (phosphorus (P) experiment) and white lupin (iron (Fe) experiment). The P and Fe sources used included biovivianite produced by microbial reduction of P-containing ferrihydrite at pH 6.5 (VivInsol6.5) and pH 7.0 (VivInsol7.0), biovivianite produced with soluble Fe(III) citrate (C6H5FeO7) in the presence of soluble phosphate at pH 7 (VivSol), and vivianite from a commercial company (ComViv). Potassium dihydrogen phosphate (KH2PO4) was used as a reference fertilizer in the P experiment, and Fe-EDDHA and Fe(II)-sulfate (FeSO4.7H2O) were used in the Fe experiment. Total P uptake by wheat plants from the product dominated by vivianite and phosphate-green rust (VivSol) was not significantly different from KH2PO4. The relative P use efficiency, i.e., the equivalence in terms of P recovery of VivSol was 74% of KH2PO4, making VivSol the effective P source for durum wheat among the products tested (aside from KH2PO4). For Fe uptake, product dominated by vivianite and metavivianite (VivInsol7.0), was the most effective Fe source for white lupin followed by Fe-EDDHA, ComViv, and VivSol with VivInsol6.5 as the least effective but without significant differences with Fe(II)-sulfate. The average crystallite sizes of the biovivianite were 59 nm, 63 nm, and 66 nm for VivSol, VivInsol7.0, and VivInsol6.5, respectively.ConclusionsThe mineral constituents of the biovivianite coupled with their nano-crystallite sizes explained its effectiveness as P and Fe fertilizers. The results reveal that biovivianite production is a novel way of producing efficient P and Fe fertilizers from P-enriched Fe sludge or P-rich water. Thus, it can be used for producing fertilizers with high P and Fe concentrations from water purification, providing new tools for a circular economy approach in the use of a non-renewable resource such as P.Graphical

A Cost Model for Ocean Iron Fertilization as a Means of Carbon Dioxide Removal That Compares Ship‐ and Aerial‐Based Delivery, and Estimates Verification Costs

AbstractWe present a cost model for implementing a deployment scale effort for conducting ocean iron fertilization (OIF) for marine‐based carbon dioxide removal (CDR). The model incorporates basic oceanographic parameters critical for estimating the effective export of newly fixed CO2 into biomass that is stimulated by Fe addition to an Fe‐limited region of the Southern Ocean. Estimated costs can vary by nearly 100‐fold between best‐case and worst‐case scenarios, with best‐case values of $7/net tonne C captured versus worst‐case $1,500/net tonne C captured, without accounting for verification costs. Primary oceanographic factors that influence cost are the net primary productivity increases achieved via OIF, the amount of C exported into the deep ocean, and the amount of CO2 ventilated back to the atmosphere. The model compares ship‐based versus aerial delivery of Fe to the ocean, and estimates aerial delivery can be 30%–40% more cost effective; however, the specific requirements for aerial delivery require additional research and development. The model also estimates costs associated with verification and environmental monitoring of OIF. These costs increase $/net tonne C captured by 3–4‐fold. Best, intermediate, and worst cases for aerial delivery and ship delivery are $21, $83, $2,033, and $24, $94, $4,691, respectively, inclusive of verification costs. The primary goal of this model is to demonstrate the variability in cost of OIF as a CDR method, and to better understand where additional research is needed to determine the major factors that may make OIF a tractable, nature‐based CDR method.

Implementation of marine CO2 removal for climate mitigation: The challenges of additionality, predictability, and governability

Achieving net zero CO2 emissions requires gigatonne-scale atmospheric CO2 removal (CDR) to balance residual emissions that are extremely difficult to eliminate. Marine CDR (mCDR) methods are seen increasingly as potentially important additions to a global portfolio of climate policy actions. The most widely considered mCDR methods are coastal blue carbon and seaweed farming that primarily depend on biological manipulations; ocean iron fertilisation, ocean alkalinity enhancement, and direct ocean capture that depend on chemical manipulations; and artificial upwelling that depends on physical manipulation of the ocean system. It is currently highly uncertain which, if any, of these approaches might be implemented at sufficient scale to make a meaningful contribution to net zero. Here, we derive a framework based on additionality, predictability, and governability to assess implementation challenges for these mCDR methods. We argue that additionality, the net increase of CO2 sequestration due to mCDR relative to the baseline state, will be harder to determine for those mCDR methods with relatively large inherent complexity, and therefore higher potential for unpredictable impacts, both climatic and non-climatic. Predictability is inherently lower for mCDR methods that depend on biology than for methods relying on chemical or physical manipulations. Furthermore, predictability is lower for methods that require manipulation of multiple components of the ocean system. The predictability of an mCDR method also affects its governability, as highly complex mCDR methods with uncertain outcomes and greater likelihood of unintended consequences will require more monitoring and regulation, both for risk management and verified carbon accounting. We argue that systematic assessment of additionality, predictability, and governability of mCDR approaches increases their chances of leading to a net climatic benefit and informs political decision-making around their potential implementation.

A Critical Review of Methodologies for Evaluating Iron Fertilizers Based on Iron Reduction and Uptake by Strategy I Plants

Under iron (Fe)-limited conditions, plants have developed strategies for acquiring this essential micronutrient. Several Fe sources have been studied as potential fertilizers, with Fe synthetic chelates being the most used to prevent and correct Fe chlorosis in crops. The determination of the activity of the Fe chelate reductase (FCR) enzyme has long been described in the literature to understand the efficiency of Strategy I plants in acquiring Fe from fertilizers under deficient conditions. Other experiments have focused on the translocation of Fe to the plant to define the effectiveness of Fe fertilizers. Yet, both assays are relevant in knowing the capacity of a novel Fe source and other compounds alleviating Fe chlorosis in Strategy I plants. This work reviews the methodologies that are used in FCR assays to evaluate novel Fe fertilizers, including the factors modulating the results obtained for FCR assay activity, such as the Fe substrate, the Fe level during the growing period and during the FCR assay, the pH, the choice of an in vivo or in vitro method, and the plant species. A discussion of the benefits of the concurrence of FCR and Fe uptake assays is then presented alongside a proposed methodology for assessing the effectiveness of Fe fertilizers, emphasizing the importance of understanding chemical and physiological plant interactions. This methodology unifies key factors that modify FCR activity and combines these with the use of the 57Fe tracer to enhance our comprehension of the efficacy of Fe-based fertilizers’ effectiveness in alleviating Fe chlorosis. This comprehensive approach not only contributes to the fundamental understanding of Fe-deficient Strategy I plants but also establishes a robust method for determining the efficiency of novel sources for correcting Fe deficiency in plants.

Analysis of tomatoes showing iron deficiency symptoms in winter under heavy fruit load

Declines in crop productivity that are thought to be due to iron deficiency have been reported even on non-calcareous-alkaline soils. For example, tomatoes exhibit iron deficiency-like symptoms (yellowing of new leaves) if the fruit load is heavy during winter. The objective of this study is to investigate the relationship between fruit load, low temperatures, low sunlight, and iron deficiency, and to explore the possibility of increasing productivity with iron-containing fertilizers. Results of an investigation of the farms experiencing iron deficiency-like symptoms in winter showed low iron concentrations and elevated expression of iron deficiency-inducible genes in yellowing leaves. To investigate the effects of heavy fruit load on iron nutrition, plants were grown in three groups: those with a medium number of fruits per truss (MED), a high number of fruits (heavy fruit load; HEAVY), and a high number of fruits with additional iron fertilization (++Fe). The SPAD leaf-color value of the new leaves and weight of the lower leaves in winter were in the order of HEAVY < ++Fe < MED. In all groups, the iron concentrations in the upper leaves in January were lower than those in October and March. RNA-seq analysis showed that the expression of genes involved in iron absorption was suppressed in the roots in January, which may have contributed to iron deficiency in winter. These results suggest that one of the factors limiting the productivity of tomatoes in winter with heavy fruit load is iron, and that productivity can be restored by iron materials.

Iron fertilization–induced deoxygenation of eastern equatorial Pacific Ocean intermediate waters during the Paleocene–Eocene thermal maximum

Abstract The Paleocene–Eocene thermal maximum (PETM), a transient period of global warming, is considered to be an important analog for future greenhouse conditions. It was accompanied by a significant carbon cycle perturbation. Although ocean deoxygenation across the PETM is reported widely, its mechanism in the open ocean remains uncertain. Here, we present magnetic and geochemical analyses of sediments from the eastern equatorial Pacific Ocean. We found that iron fertilization during the PETM by eolian dust and volcanic eruptions fueled eastern equatorial Pacific Ocean productivity. This process led to increased organic matter degradation and oxygen consumption in intermediate waters, leading to deoxygenation. Our findings suggest that iron fertilization could be an important driver of open-ocean oxygen loss, as a side effect of global warming.

Transient Response of Southern Ocean Ecosystems During Heinrich Stadials

AbstractAntarctic ice core records suggest that atmospheric CO2 increased by 15–20 ppm during Heinrich stadials (HS). These periods of abrupt CO2 increase are associated with a significant weakening of the Atlantic meridional overturning circulation (AMOC), and a warming at high southern latitudes. As such, modeling studies have explored the link between changes in AMOC, high southern latitude climate and atmospheric CO2. While proxy records suggest that the aeolian iron input to the Southern Ocean decreased significantly during HS, the potential impact on CO2 of reduced iron input combined with oceanic circulation changes has not been studied in detail. Here, we quantify the respective and combined impacts of reduced iron fertilization and AMOC weakening on CO2 by performing numerical experiments with an Earth system model under boundary conditions representing 40,000 years before present (ka). Our study indicates that reduced iron input can contribute up to 6 ppm increase in CO2 during an idealized Heinrich stadial. This is caused by a 5% reduction in nutrient utilization in the Southern Ocean, leading to reduced export production and increased carbon outgassing from the Southern Ocean. An AMOC weakening under 40ka conditions and without changes in surface winds leads to a ∼0.5 ppm CO2 increase. The combined impact of AMOC shutdown and weakened iron fertilization is almost linear, leading to a total CO2 increase of 7 ppm. Therefore, this study highlights the need of including changes in aeolian iron input when studying the processes leading to changes in atmospheric CO2 concentration during HS.

Chelated- and nano iron fertilization affects nutrient uptake and translocation in fresh market tomatoes

Our study aimed to evaluate the effects of nano and chelated Fe fertilization on nutrient and heavy metals uptake and their translocation from soil to root, stem, leaf, and fruits of fresh market tomatoes (Solanum Lycopersicon, cv. Sunbrite). A completely randomized design in a factorial experiment, with two Fe sources (nano vs. chelated) applied at 0 (control), 10, 20, and 40 mg/L via drip-irrigated plasticulture, was conducted. Nutrient and heavy metals concentrations in soil, water, tomato roots, stems, leaves, and fruits were determined. Soil had higher K, Fe, Ca, Mg, P, and Mn but lower Ni, Cd, and Cr concentrations. The P, K, Fe, Cu, Mn, and Na concentrations in the roots were significantly affected by both nano and chelated Fe fertilization; however, without following a consistent pattern. Averaged across the Fe treatments, K, Ca, Mg, Fe, and P that translocated from the soil were dominated in the roots, stems, and leaves. The nutrient translocation order, from roots to fruits in response to Fe fertilization, was nano Fe (40%) > chelated Fe (37%) > control (23%). Based on the treatment index values calculated across treatments, it is evident that Fe fertilization plays a pivotal role in nutrient uptake and translocation. The use of chelated Fe at a concentration of 20 mg/L had a pronounced effect on improving the nutritional quality of the tomatoes and, by extension, their associated public health benefits. In conclusion, the chelated Fe (20 mg/L) stands out as the most preferable and effective Fe fertilization for tomatoes.

Upwelling-driven biogenic silica accumulation in the Yangtze Sea, South China during Late Ordovician to Early Silurian time: A possible link with the global climatic transitions

Silica accumulation in the Yangtze Sea during the Ordovician–Silurian (O–S) transition appears to have coincided with global climatic fluctuations, widespread upwelling, and volcanism. There is a need to further evaluate their respective contributions to silica deposition and potential relationships among these factors. The current study selected siliceous deposits in the Wufeng and Longmaxi Formations from four sections spanning the inner to outer Yangtze Sea, South China, to gain a deeper understanding of the climatic and oceanographic evolution associated with silica enrichment. Al/(Al + Fe + Mn) values, the presence of radiolarians, and Si isotope values of samples recovered from the investigated shale successions offer compelling evidence that the silica is largely of biogenic origin with some terrigenous contributions. Further, various productivity and redox proxies suggest that biogenic silica (BSi) accumulated under conditions of enhanced marine productivity and anoxic bottom water conditions. Hg/TOC and Zr/Al2O3 profiles suggest intermittent volcanism during the BSi deposition in the Yangtze Sea. However, the lack of correlation between BSi and Hg/TOC values indicates that volcanic iron fertilization was not responsible for BSi accumulation. Instead, most BSi-rich samples are dominated by low MnEF × CoEF values (<0.5), consistent with BSi deposited in modern upwelling settings. Hydrographic reconstruction based on Mo–U covariation indicates a more open water setting in the outer Yangtze Sea, while the coeval inner Yangtze Sea was relatively restricted. Therefore, upwelling events appear to have been more vigorous in the outer Yangtze Sea. Published and new Chemical Index of Alteration (CIA), BSi, and MnEF × CoEF data for the Wufeng and Longmaxi Formations across the inner to outer Yangtze Sea demonstrate that temporal and spatial variations of BSi were controlled by climate-driven upwelling. In particular, cool-water upwelling contemporaneous with Hirnantian glaciation may have been responsible for the establishment of the cool-water fauna of the shallow-water Guanyinqiao Bed and enhanced silica deposition in deeper water. Moreover, a moderate negative relationship between compiled CIA and BSi contents suggests that enhanced upwelling driving BSi accumulation appears to have been favored during cooling events. Integrated analysis of BSi deposits of the Laurentia and Baltica continental margins further suggests that BSi accumulation on continental margins during the O–S transition was primarily influenced by global cooling. Therefore, we suggest that wind patterns or/and thermohaline circulation, influenced by climate fluctuations, induced widespread cold water upwelling events during the O–S transition. Moreover, elevated BSi production diluted accumulating OM resulting in the observed parabolic relationship of BSi and TOC.

Effects of magnetoelectric water irrigation combined with foliar iron fertilizer on the growth characteristics and iron absorption of spinach

Vegetable cultivation is highly profitable and can quickly generate earnings. The demand for vegetables is increasing daily compared with grain crops. However, the inefficient use of water resources and the lack of microelements in soil prevent improvements in vegetable quality and yield. This study conducted indoor pot experiments on spinach (Spinacea oleracea L.), including five concentrations of foliar iron (e.g., 0, 15, 30, 45, and 60 mg/L) under conventional water and magnetoelectric water irrigation conditions. This experiment was conducted to clarify the effect of the combined application of magnetoelectric water and foliar iron fertilizer on the growth characteristics and iron absorption patterns of spinach. The results demonstrated that magnetoelectric water combined with the application of 15 mg/L foliar iron fertilizer was the most effective combination. These results occurred by (1) increasing the available iron content in the soil while promoting the accumulation of total nitrogen in spinach leaves and (2) increasing the chlorophyll content and maximum net photosynthetic rate of spinach leaves. This resulted in a significant increase of 31.91 % in the aboveground fresh weight of spinach and an iron enrichment coefficient of 40.12 %. Additionally, the accuracy of the logistic growth and light response model to simulate the growth and light response process of spinach was greater than 0.98, indicating good fitting effects. The increase in chlorophyll content was the main factor promoting spinach growth and iron absorption, and the prediction model of spinach yield based on chlorophyll content was well fitting. These results provide theoretical references and technical support for promoting magnetoelectric water irrigation technology combined with foliar iron fertilizer to improve vegetable yields.

Assessing the Ecological Implications of Ocean Iron Fertilization: Insights from Post-Eruption Volcanic Processes

This study proposes the usage of post-eruption volcanic processes as a natural analog for assessing the potential impacts of man-made iron fertilization on ocean ecosystems. Data is compiled from the 14 most explosive volcanic eruptions since 1884 to establish correlations between climate temperature anomalies and phytoplankton growth induced by volcanic tephra fallout in addition to other post-eruption variables. Through a comparative analysis of the contrasting strengths of these relationships using a student t-test for statistical significance, multivariable regression analysis, and linear regression interpretation, the scale of ocean iron fertilization is quantified. Two well-documented modern volcanic eruptions in Hawaii and Iceland are additionally employed as case studies to provide a comprehensive understanding of micro phenomenons occurring post-eruption. Rapid algae growth is demonstrated in High Nutrient Low Chlorophyll regions (HNLC), where long-term growth can be sustained for up to six months. Statistical results isolate the effect of stratospheric injection from ocean iron fertilization, demonstrating the effectiveness of tephra ash fallout in inducing regional phytoplankton growth. In all, these findings contribute to a comprehension of the potential ecological consequences of iron fertilization efforts, an approach to assess environmental implications without direct experimentation.

Impact of foliar application of iron and zinc fertilizers on grain iron, zinc, and protein contents in bread wheat (Triticum aestivum L.).

Micronutrient deficiencies, particularly iron (Fe) and zinc (Zn), are prevalent in a large part of the human population across the world, especially in children below 5 years of age and pregnant women in developing countries. Since wheat constitutes a significant proportion of the human diet, improving grain Fe and Zn content in wheat has become important in improving human health. This study aimed to quantify the effect of foliar application of iron sulfate heptahydrate (FeSO4.7H2O) and zinc sulfate heptahydrate (ZnSO4.7H2O) and their combination on grain Fe and Zn concentrations, as well as grain protein content (GPC). The study also aimed to assess the utility of these applications in large field conditions. To address this issue, field experiments were conducted using 10 wheat cultivars and applying a foliar spray of FeSO4.7H2O (0.25%) and ZnSO4.7H2O (0.50%) separately (@400 L of solution in water per hectare during each spray) and in combination at two different crop growth stages (flowering and milking) for three consecutive crop seasons (2017-2020). The study used a split-plot design with two replications to assess the impact of foliar application on GFeC, GZnC, and GPC. In addition, an experiment was also conducted to assess the effect of soil (basal) @ 25 kg/ha ZnSO4, foliar @ 2 kg/ha, ZnSO4.7H2O (0.50%), and the combination of basal + foliar application of ZnSO4 on the grain micronutrient content of wheat cultivar WB 02 under large field conditions. GFeC increased by 5.1, 6.1, and 5.9% with foliar applications of FeSO4, ZnSO4, and their combination, respectively. GZnC increased by 5.2, 39.6, and 43.8% with foliar applications of FeSO4, ZnSO4, and their combination, respectively. DBW 173 recorded the highest increase in GZnC at 56.9% with the combined foliar application of FeSO4 and ZnSO4, followed closely by HPBW 01 at 53.0% with the ZnSO4 foliar application, compared to the control. The GPC increased by 6.8, 4.9, and 3.3% with foliar applications of FeSO4, ZnSO4, and their combination, respectively. Large-plot experiments also exhibited a significant positive effect of ZnSO4 not only on grain Zn (40.3%, p ≤ 0.001) and protein content (p ≤ 0.05) but also on grain yield (p ≤ 0.05) and hectoliter weight (p ≤ 0.01), indicating the suitability of the technology in large field conditions. Cultivars exhibited a slight increase in GFeC with solitary foliar applications of FeSO4, ZnSO4, and their combination. In contrast, a significant increase in GZnC was observed with the foliar application of ZnSO4 and the combined application of FeSO4 and ZnSO4. In terms of GPC, the most significant enhancement occurred with the foliar application of FeSO4, followed by ZnSO4 and their combination. Data demonstrated the significant effect of foliar application of ZnSO4 on enhancing GZnC by 39.6%. Large plot experiments also exhibited an increase of 40.3% in GZnC through the foliar application of ZnSO4, indicating the effectiveness of the technology to be adopted in the farmer's field.

On the Variability of Equatorial Pacific Nitrate and Iron Utilization

The tropical Pacific is one of the largest ocean regions on Earth where the trace element iron limits new primary production and therefore the efficiency of carbon export to the deep sea. Although there is a long history of marine biogeochemical research in the tropical Pacific, recent advancements using GEOTRACES key parameters such as iron and nitrate isotopes (nitrate δ15N and δ18O) make this a good time to review the current understanding of tropical Pacific nitrate dynamics—how both regional subsurface nitrate characteristics and surface ocean nitrate utilization change with time. While this article provides a comprehensive overview of the biological, chemical, and physical processes shaping equatorial Pacific subsurface-to-surface nutrients, it principally explores the findings from the first nitrate isotope time series in iron-limited high nutrient, low chlorophyll waters. Results indicate that the preferential recycling of bioavailable iron within the euphotic zone is required to explain even the lowest observed nitrate utilization in the eastern equatorial Pacific (EEP). Furthermore, because seasonal-to-interannual nitrate utilization variability in the EEP cannot be driven by changes in iron supply, this work argues that iron recycling (and therefore bioavailable iron) is modulated by upwelling rate changes, creating a predicted and recently observed spectrum of iron limitation in the iron-limited EEP surface waters. In other words, upper ocean physics overwhelmingly dominates seasonal-to-interannual nitrate utilization in the iron-​limited EEP. This new understanding of nitrate utilization in iron-limited waters helps to explain long-term changes in past equatorial Pacific nitrate utilization obtained via sedimentary proxy records and potentially complicates the efficacy of future iron fertilization of the equatorial Pacific.

Potential impact of iron oxide conjugated nano-fertilizer on growth, flowering and isozyme expression in Gardenia jasminoides

Nano-fertilizers protect the soil from the excessive addition of traditional fertilizers, enhancing the efficiency of the elements and diminishing the number of additive fertilizers. The effect of Fe2O3NPs-Boron (Fe2O3NPs-B), and Fe2O3 NP-Humic Acid (Fe2O3NPs-HA) at 100, 150 and 250 ppm, Fe2O3, and control (without any iron fertilizers) on the vegetative growth, flowering, photosynthetic pigments, nutrient element content and isozymes activity (peroxidase, superoxide dismutase and polyphenol oxide) of Gardenia jasminoides plants was investigated. Gamma-rays at 25 kGy were conducted for the promising synthesis of Fe2O3NPs-B, and Fe2O3NPs-HA. The experiment was carried out under greenhouse conditions during two successive seasons. The results stated that Fe2O3NPs-B and Fe2O3NPs-HA at the highest concentration (250 ppm) had a significant positive effect in all vegetative characteristics, photosynthetic pigments, nutrient element content and isozymes activity. Fe2O3NPs-HA showed the optimal result in all morphological and biochemical characteristics. The highest activity of enzymes appeared in the treated plants with Fe2O3 NPs-B followed by Fe2O3 NPs-HA at 250 ppm. The advantage nano-fertilizer usage may be summarized as saving the soil from the unreasonable accumulation of classic fertilizers, improving the use efficiency of parts and reducing the number of different fertilizers as a consequence of their increased surface area and their nano-size.

Response of some Growth Traits of Maize Plants to Conventional and Nano-Fertilizers

The Agricultural Research Station in the university city associated with the College of Agriculture at the University of Kufa undertook a fall 2022-2023 field experiment. The study examined the effects of zinc and iron nanoparticles at 2g.l-1 or 3g.l-1, conventional iron and zinc fertilizer at 3g.l-1, and distilled water on maize plant growth and development. A three-replication Randomized Completely Block Design (RCBD) factorial experiment was done. Nano-fertilization with nano-zinc at 3g.l-1 produced the best results across various vegetative development indicators. Plant height rate, stem diameter, leaf chlorophyll, nitrogen, and phosphorus content are these indicators. However, 3g.l-1 nano iron increased leaf area the highest, reaching 0.424 m2.plant-1. This treatment also produced the most rows per ear and the maximum leaf potassium concentration. In contrast, 1.5 g.L-1 traditional zinc and 1.5 gm.L-1 conventional iron fertilizer produced better vegetative growth and production. These included plant height, average stem diameter, leaf chlorophyll, and leaf elements (NPK). Additionally, 3 g.L-1 conventional iron produced the maximum leaf area. Overall, the 1.5 g.L-1 nano-zinc and 1.5 g.L-1 nano-iron fertilizer combination had higher vegetative growth rates than other combinations. However, the combination of 1 g.L-1 nano-iron and 1.5 g.L-1 nano-zinc had the maximum leaf area and potassium concentration.

Effect of Iron Treatment and Fertilizer of High Phosphorous (N.P.K) on Vegetative and Flowering Growth of Lalla Abbas plant, Mirabilis jalaba L.

Effect of Iron Treatment and Fertilizer of High Phosphorous (N.P.K) on Vegetative and Flowering Growth of Lalla Abbas plant, Mirabilis jalaba L.

Response of seedling barley (Hurdeom vulgar, L.) to foliar fertilization of nano-oxides (Fe, Cu, Mg)

Background. An experiment was conducted at the Grain Technology Laboratory, Crop Department, Faculty of Agriculture, Omar Al-Mukhtar University, during the 2023 season. The experiment utilized a completely randomized design to study the response of barley to foliar application of fine nanoscale iron, manganese, and copper fertilizers. The application was carried out as foliar spray at two different doses, two weeks and one month after sowing, using 3 kg capacity pots with 20 seeds per pot. The experiment included three observations for each treatment, with the nanoscale iron, manganese, and copper oxides applied at a concentration of 1 cmol/L. The data revealed the following: Significant positive response of barley shoots to foliar application of nanoscale iron, manganese, and copper fertilizers in various growth indicators, including shoot weight, shoot length, leaf area, crop growth rate, and specific leaf weight. High significant differences were observed in the effect of nanoscale iron, manganese, and copper oxides on the average shoot weight, crop growth rate, and leaf area. Copper oxide and manganese oxide showed the highest means, followed by iron oxide, compared to the control. Iron oxide exhibited the highest specific leaf weight for barley shoots, followed by copper oxide and then manganese oxide, compared to the control treatment.

Increasing iron use efficiency by controlling emitter clogging in drip irrigation systems

Iron is one of the essential elements for crop growth. Traditional iron fertilizer application method by injecting iron into soil results in low utilization efficiency of iron fertilizer and a considerable amount of iron residue in the soil. Applying iron fertilizer by drip irrigation system could effectively improve the utilization efficiency of iron fertilizer. However, emitter clogging seriously restrict this technology. Here, the effects of different types of iron fertilizers [Ferrous sulfate (FeSO4); Ferric citrate (FC-Fe); Sodium ferric ethylenediamine tetraacetate (EDTA-Fe); And no iron fertilizer (CK)] on emitters clogging were assessed. The components of emitter clogging substances were detected through X-ray Diffraction and Fourier Transform Infrared Spectrometer. The results showed that different types of iron fertilizers significantly affected emitter clogging. EDTA-Fe application significantly mitigated emitter clogging, reduced the total amount of clogging substances by 49.6% on average, and increased the emitter flow rate by 21.0%. This is due to EDTA-Fe chelated scaling cations (e.g., Ca2+) in water through its functional groups, thereby reducing the contents of calcite, monohydrate calcite and dolomite. However, FeSO4 and FC-Fe application aggravated emitter clogging, and increased the total clogging substances by 52.3% and 105.8%, respectively. Surprisingly, iron precipitation was not detected in the clogging substances. FeSO4 and FC-Fe aggravated clogging mainly by increasing the formation of particulate fouling (e.g., muscovite) and chemical precipitation (e.g., calcite). This study suggested choosing EDTA-Fe in drip irrigation systems to reduce emitter clogging. The research results are of significance for improving the utilization efficiency of iron fertilizer and promoting the application of iron fertilizer drip irrigation technology.

Influence of iron fertilizer form and concentration on bioelectricity and methane emission from hydroponic plant microbial fuel cells

This study aimed to evaluate the effect of iron form (Fe2+ and Fe3+) and concentration (0 μM, 7.5 μM, and 15 μM) on the biomass production, bioelectricity generation, and methane (CH4) emissions of hydroponic plant microbial fuel cells (H-PMFCs). Rice plants (Oryza sativa L.) were grown in H-PMFCs. During the 90 days of operation, the highest power density (PDmax) was observed in Group 7.5–15 of 949.17 mW/m3. When adding single-form iron (Fe2+ or Fe3+), the PDmax of H-PMFCs was positively correlated with iron concentration. Further, the H-PMFC feed with Fe3+ showed higher power output than the feed with Fe2+. Adding 7.5 μM Fe2+ and 15 μM Fe3+ (Group 7.5–15) showed the highest overall biomass production, including plant lengthavg/plant (89.67 ± 1.17 cm) and plant weightavg/plant (14.91 ± 0.02 g dry mass) and lowest CH4 emission (43.15 ± 2.00 g/m2). The CH4 emission test indicated that the addition of iron in rice H-PMFCs can decrease the emission of CH4 in two ways: (i) iron electron acceptors directly inhibit methanogens; (ii) iron electron acceptor enhances the electricity production ability of MFC to inhibit CH4 production. Therefore, adding 7.5 μM Fe2+ and 15 μM Fe3+ showed great potential to enhance the performance of H-PMFCs on biomass production, bioelectricity generation, and CH4 emission inhibition.