Agricultural application of vanadium and vanadium-containing compounds, and processes serving the same

Abstract

The invention relates to the use of ecologically sustainable catalysts not previously applied in the field of agriculture, and to related methods, by means of which a higher rate of atmospheric nitrogen fixation can be achieved and agriculturally advantageous effects can be realized while simultaneously avoiding the harmful effects associated with conventional nitrogen fertilization. More specifically, the invention relates to the novel agricultural application of dissociated vanadium ions possessing redox potential, and to related methods. The method according to the invention is suitable for increasing the yield and biomass of plants, the essence of which lies in applying vanadium to the plant growth medium, to the plant, or to both, in order to enhance the nitrogen-fixing capability of microorganisms capable of fixing atmospheric nitrogen.

Description

[0001] Agricultural Application of Vanadium and Vanadium-Containing Compounds,

[0002] and Processes Serving the Same

[0003] Field of the Invention

[0004] The present invention relates to the field of agriculture, in particular to ecologically sustainable approaches aimed at increasing yields achievable in crop production, and to methods and materials applicable for this purpose. More specifically, the field of the invention encompasses the use of vanadium-containing compounds (“catalysts”), applied in liquid form, for microorganisms capable of fixing atmospheric nitrogen, as well as processes serving this purpose, wherein vanadium constitutes the central element. By means of the method according to the invention, the benefits derived from nitrogen fertilization of plants can be maintained while avoiding its harmful effects.

[0005] Subject Matter of the Invention

[0006] In line with the above, the subject matter of the invention comprises the use of catalytically active compounds - previously not applied for this purpose in agriculture - that are ecologically sustainable, as well as the related processes. Through their application, a higher rate of atmospheric nitrogen fixation can be achieved, and agriculturally advantageous effects can be realized while simultaneously avoiding the harmful effects associated with conventional nitrogen fertilization. More specifically, the subject matter of the invention comprises the novel agricultural application of dissociated (redox -potentialbearing) ions of a chemical element not previously used for this purpose, namely vanadium, as well as the related processes. Even more specifically, the subject matter of the invention comprises the use of vanadium-containing compounds and related processes that are capable of exerting a catalytic effect on microorganisms able to fix atmospheric nitrogen, with respect to this property. Most specifically, the subject matter of the invention comprises the use of vanadium-containing compounds for enhancing the nitrogen-fixing capability of microorganisms capable of fixing atmospheric nitrogen, and processes suitable for this purpose . A unique advantage of the solution according to the invention is that it provides all the benefits achievable through conventional nitrogen fertilization, while at the same time eliminating its adverse properties.

[0007] Background of the Invention

[0008] Nitrogen is one of the most important macronutrients for plants, as it plays a fundamental role in the formation of proteins, enzymes, nucleic acids (DNA, RNA), and chlorophyll. In agriculture, ensuring an adequate supply of nitrogen is essential for healthy plant development, increasing crop yields, and maintaining soil fertility.

[0009] Nitrogen may originate from natural or artificial sources. Natural sources include atmospheric nitrogen and nitrogen present in the soil. Atmospheric nitrogen can be biologically fixed by certain bacteria, and nitrogen is also released through the decomposition of organic matter in the soil, such as plant residues and animal excreta. In addition, rainfall and lightning may also contribute to the nitrogen cycle. Artificial sources include mineral fertilizers or organic fertilizers. Nitrogen-based mineral fertilizers (e.g. ammonium nitrate, urea) provide readily available nitrogen to plants, while organic fertilizers such as manure, compost, and green manuring also contribute to replenishing the nitrogen reserves of the soil.Nitrogen plays a prominent role in plant life, particularly in leaf and stem growth, enhancement of photosynthesis, and the production of proteins and enzymes essential to the plant’s life cycle. Nitrogen deficiency in plants leads to yellowing (chlorosis), slow growth, and reduced yields. Nitrogen is also a fundamental component of chlorophyll, and therefore has a direct impact on the efficiency of photosynthesis. Furthermore, it is indispensable for the synthesis of plant proteins and enzymes that are of increased importance for plant development and stress resistance.

[0010] Although the use of nitrogen-based fertilizers has proven effective, this method may also involve several disadvantages, since excess nitrogen can be leached from the soil and cause nitrate contamination of surface waters and groundwater. It should also be noted that excessive amounts of nitrogen present in the soil may result in overly lush vegetative growth, which reduces the structural strength of plants. Excessive nitrogen fertilization may further contribute to the process of global warming, as greenhouse gases derived from surplus nitrogen, such as nitrogen oxides, may be released into the atmosphere.

[0011] Although, in line with the above, nitrogen plays a key role in plant development and agricultural crop yields, the application of sustainable farming practices is nevertheless indispensable in order to reduce environmental damage. While sustainable nitrogen management is generally pursued in agriculture through the application of nitrogen at the most appropriate dosage and with optimal timing, through green manuring, and through monitoring of nutrient supply, there is an exceptional demand for methods that are capable of providing plants with an optimal amount of nitrogen while retaining the beneficial effects of nitrogen fertilization and simultaneously avoiding the harmful effects resulting from nitrogen loading of arable soils.

[0012] Vanadium (V) is a transition metal, the 23rd element of the periodic table. It is a silver-gray, moderately hard metal that exhibits good resistance to corrosion and oxidation. In nature, it occurs in minerals, most commonly in the form of vanadinite and carnotite, but it is also found in various iron ores and oil sands. Vanadium may be present in several oxidation states, among which the +5 oxidation state is the most stable. Vanadium is most commonly obtained from vanadium -containing ores or as a by-product during the processing of iron ores. The main steps of its production include oxidation of the ores, chemical reduction, and electrolysis. The most important application of vanadium is in the production of high-strength steel alloys for the automotive industry, aircraft manufacturing, toolmaking, and the construction industry. Vanadium is also used as a catalyst in the form of vanadium pentoxide (V2O5) in sulfuric acid production, and it is applied in other important chemical industrial processes as well, such as ammonia oxidation or petroleum refining. Vanadium also plays a significant role in energy storage, particularly in the stabilization of renewable energy sources (solar and wind power plants), as vanadium redox batteries are long-lived, rechargeable, and highly suitable for storing large amounts of energy. Vanadium is further used as a coloring agent in glass manufacturing, in ceramics and paints, and vanadium-based compounds are also employed in specialized semiconductors and in certain medical research applications. Although vanadium occurs only in trace amounts in the human body, it may play a role in the functioning of certain enzymes, and some marine organisms, such as mollusks, utilize vanadium in their biological processes.

[0013] As is apparent from the foregoing, vanadium is applied in a wide range of fields, and it is also evident that its agricultural use as a “catalyst,” as described in the present invention, was previously unknown. According to the agricultural application and the related processes forming the subject matter of the present invention, the effect of vanadium -containing compounds is not exerted directly on plants. Since plants are not capable of directly utilizing nitrogen present in the atmosphere, the application and processes according to the invention enhance the nitrogen-fixing capability of the entire range of organisms living in symbiosis with plants and capable of fixing atmospheric nitrogen, which has asignificant effect on plant growth. Atmospheric nitrogen-fixing organisms convert the fixed nitrogen into a form that is available for plant uptake, as a result of which plants are able to utilize nitrogen originating from the atmosphere indirectly, which is essential for their growth. Within the scope of the present invention, the microorganisms living in symbiosis with plants and capable of fixing atmospheric nitrogen include, without limitation, soil bacteria, root-nodule bacteria (nodulating symbionts), actinomycetes, soil yeasts, microscopic fungi, and cyanobacteria. The nitrogen fixed by nitrogen-fixing bacteria — after being converted into a form available to plants - can thus be utilized indirectly by the plants.

[0014] The present invention is based on the recognition that the process of nitrogen uptake and fixation can be promoted, catalyzed, and accelerated for bacteria if a vanadium source — of high significance for their vital biological processes — is made available to them, since vanadium plays a key role for atmospheric nitrogen-fixing taxa of the biosphere in the biogeochemical processes required for nitrogen fixation. As the amount of vanadium originating from spontaneous biogeochemical processes is typically low and its spatial distribution is far from optimal, there is a need for the appropriate supplementation of vanadium in vanadium-free and vanadium-deficient areas. The presence of vanadium in higher quantities on the side of atmospheric nitrogen-fixing organisms results in significantly increased fixation of atmospheric nitrogen, thereby making a greater amount of nitrogen available to plants in a readily assimilable form.

[0015] Although vanadium is a relatively abundant element on Earth (0.015% in the uppermost 16 km of the Earth’s crust), its distribution is highly uneven and it occurs predominantly in mineral form, in which state it is not accessible to nitrogen-fixing organisms, meaning that its availability and usability for plants is also very limited. Nitrogen (0.03%) is approximately twice as abundant, and due to its presence in the atmosphere in gaseous form, its distribution is much more uniform. In the nitrogen cycle (nitrificationdenitrification), the atmosphere represents a significant reservoir of nitrogen molecules, and in the presence of vanadium, nitrification is accelerated, thereby increasing the amount of nitrogen available for plant uptake. In the catalytic process, the role of vanadium within the metal-enzyme ligand complex is what enhances nitrification capacity. The atmospheric nitrogen reservoir amounts to approximately 57,000-77,000 t / ha; however, molecular nitrogen can only be fixed by the aforementioned microorganisms. The best-known symbiotic systems fix approximately 100-300 kg of nitrogen per hectare per year, of which 75-90% is transferred to the plant in the form of assimilates — predominantly simple amino acids. During biological nitrogen fixation, vanadium supplies the additional electrons required for the reduction of nitrogen molecules via enzymatic electron transfer, presumably acting as a valence-changing metalloprotein. Vanadium is suitable for such valence changes due to its transitionmetal properties. The catalytic effect of vanadium manifests only if the vanadium -containing compound is capable of valence change, that is, if it possesses an active redox potential. The most obvious — though not exclusive — solution for ensuring this, within the scope of the invention, is the use of vanadium compounds that readily dissociate in water. Nearly all vanadium occurs in the Earth’s crust in strongly covalently bound, zero-valent crystalline form, and can only be made available for use after extraction and processing.

[0016] State of the Art

[0017] Although the biological activity and role of vanadium have been investigated on numerous occasions, ranging from microorganisms to humans, the state of the art contains no reference whatsoever to its agricultural application or to its use as a catalyst for enhancing nitrogen fixation by microorganisms.The biological role of vanadium was first reported in 1904, when plant experiments described its fungicidal effects. For most higher organisms, vanadium is either an essential trace element or biologically neutral, whereas for most lower organisms its presence is typically essential and, in the case of nitrifying and nitrogen -fixing microorganisms, efficiency -enhancing (catalytic).

[0018] As mentioned above, the state of the art contains no indication whatsoever of the agricultural application of vanadium, which means that no skilled person worldwide has previously arrived at the recognition that the application of this transition metal could exert any effect on any stage of a plant’s life cycle, and even less so that the application of vanadium could exert a catalytic effect on the life processes of any living organism. Accordingly, the concept forming the basis of the invention is unique, and the method disclosed in the present application exhibits effects that are surprising and unexpected for the skilled person.

[0019] Detailed Description of the Invention

[0020] In accordance with the foregoing, the subject matter of the invention comprises the use of ecologically sustainable catalysts, not previously applied in the field of agriculture, and the related processes, by means of which a higher rate of atmospheric nitrogen fixation can be achieved and agriculturally advantageous effects can be realized while simultaneously avoiding the harmful effects associated with conventional nitrogen fertilization.

[0021] As already mentioned, significant efforts are made in agriculture to ensure that nitrogen — required for optimal plant growth but present in the soil in lower-than-optimal quantities — is replenished only in the lowest still optimal amounts through fertilizer application, with particular emphasis on green manuring and continuous monitoring of nutrient replenishment. Nevertheless, despite their effectiveness, these methods involve considerable costs and environmental burdens. Consequently, there is an exceptional demand for methods that are capable of providing plants with an optimal amount of nitrogen while retaining the beneficial effects of nitrogen fertilization and simultaneously avoiding the harmful effects resulting from nitrogen loading of arable soils.

[0022] According to the present invention, this problem is solved by a method which, in accordance with a previously undescribed and to the skilled person unknown approach, supplies plants with the nitrogen required for growth by enhancing the nitrogen-fixing capability of microorganisms capable of fixing atmospheric nitrogen. The invention is based on the recognition that the fixation of atmospheric nitrogen by nitrogen-fixing microorganisms — and, through this, the uptake and assimilation process by plants — can be catalyzed if a vanadium source indispensable for the nitrogen-fixation process is made available to these microorganisms. As a result of the presence of vanadium in higher quantities, the aforementioned microorganisms fix significantly greater amounts of atmospheric nitrogen, which leads to more vigorous plant growth, increased plant biomass, and higher yields. The increased amount of nitrogen fixed as a result of vanadium application is taken up by plants from the nitrogen-fixing microorganisms through conventional biological processes.

[0023] A unique advantage of the solution according to the invention is that it provides all benefits achievable through conventional nitrogen fertilization, while eliminating its adverse properties. In practice, this means that higher amounts of nitrogen or an adequate nitrogen supply are provided to plants through the enhancement of the nitrogen-fixing capability of atmospheric nitrogen-fixing microorganisms, without subjecting the soil to nitrogen-containing substances, in particular mineral fertilizers. In this manner, faster and more extensive plant development can be ensured, while simultaneously avoidingnitrate contamination of surface waters and groundwater caused by nitrogen leaching, deterioration of the physical properties of plants — particularly a reduction in structural strength due to excessive vegetative growth — and the release of greenhouse gases, such as nitrogen oxides.

[0024] In carrying out the solution according to the invention, vanadium is applied in forms suitable for uptake by nitrogen-fixing microorganisms and for integration into their biochemical processes. For this purpose, while taking economic considerations into account to the greatest extent possible, the most readily available forms of vanadium are used. However, it is clear to the skilled person from the present description that other similarly dissociating vanadium compounds may also be used for the intended purpose without limitation. Accordingly, the use of the vanadium compounds referred to herein and in the examples of the present application shall in no way be regarded as limiting.

[0025] In the method according to the invention, vanadium may be applied using spraying and irrigation techniques commonly employed in the field, before or after sowing, or directly onto the plants, including application by seed treatment (seed coating). The safe and effective application rate, calculated on the basis of vanadium content and determined from experimental results, may be defined as 2-10 g / ha, with the proviso that the lowest amounts are recommended primarily for seed treatment (seed dressing), the intermediate doses are most suitable for soil treatment, while the highest doses are recommended for crop canopy treatment or for sequenced treatment (soil + crop canopy). Furthermore, in all cases it is advisable to take into account the requirements of the crop species to be cultivated, in particular its phenology-dependent nitrogen demand, the soil type and its nitrogen-supplying capacity, and the freely available soil water content, and to determine the application rate and timing accordingly. The application of vanadium according to the invention is equally feasible in open-field cultivation, in closed cultivation systems, as well as in any support medium or in hydroponic systems.

[0026] The solution according to the invention provides the above-mentioned advantages while at the same time complying with the strictest environmental and nature conservation guidelines, and can therefore be integrated into conventional, integrated, and organic farming systems alike. According to previous practices of utilizing atmospheric nitrogen, nitrogen-fixing microorganisms — primarily bacteria, and more recently nitrogen-accumulating bacteria — have been applied to agricultural land, for example by means of organic fertilizers, in accordance with the above-described approaches. In contrast, the solution according to the present invention provides a radically new approach, whereby the nitrogen-fixing capacity of nitrogen-fixing microorganisms ubiquitously present in the biosphere is enhanced. Compared to conventional nitrogen-supplementation methods, the method according to the invention is more advantageous, more economical, and more environmentally friendly. Furthermore, since vanadium and the vanadium-containing compounds applied according to the invention are non-living substances, no issues arise with respect to potential transformative effects of applied microorganisms on the native microbiome. A further major advantage of the solution according to the invention is that it is non-selective with respect to both plants and atmospheric nitrogen-fixing microorganisms, meaning that it can be applied to any plant species and any microorganism, and is therefore universally applicable in any agricultural region and area.

[0027] Examples

[0028] In order to demonstrate the surprising and unexpected effects of the solution according to the invention, targeted investigations were carried out under laboratory conditions.The investigations were conducted as container-based tests. The most commonly commercially available form of vanadium is vanadium pentahydrate; however, in the experiments, dehydrated or water-dissociated vanadium sulfate was used as the vanadium source for the microorganisms, in the form VOSOXTLO , where the value of x ranges from 0 to 6. There is no difference between the applicability of the aforementioned vanadium compounds, since each of these complex compounds dissociates very rapidly in aqueous media, and the ions containing the central vanadium atom — due to their ability to undergo valence changes and their stability — exert a catalytic effect during atmospheric nitrogen fixation. As noted above, the range of vanadium compounds that may be applied is not particularly limited. It is clear to the skilled person, based on the description and the examples, that any vanadium compound exhibiting similar dissociation behavior may be applied in an obvious and equivalent manner for the purposes of the invention.

[0029] Example 1: Investigation on Species with Different Nitrogen Demands and Nitrogen Responses

[0030] In each case, the experiments were repeated eight times. In designing the experiments, data available in the scientific literature regarding the nitrogen demand of the respective plant species were taken as a basis. Accordingly, the range of test plants was as follows (four cultivated species — three dicotyledonous and one monocotyledonous — and one wild-growing dicotyledonous species):

[0031] • a species known to be symbiotic with nitrogen-fixing bacteria and having a high nitrogen demand (common bean / Phaseolus vulgaris)

[0032] • a species exhibiting an exceptionally high nitrogen demand at all stages of development (white cabbage / Brassica oleracea convar. capitata var. alba)

[0033] • a species exhibiting increased nitrogen demand exclusively at the end of its ontogenetic development, during the generative stage — which was intentionally not addressed by the experiment (tomato / Solarium lycopersicum)

[0034] • a species with increased nitrogen demand at germination and toward the end of the life cycle, but reduced demand in the intermediate period (onion / Allium cepa)

[0035] • a nitrogen-indifferent wild plant species (meadow sage / Salvia pratensis)

[0036] Based on the above, it was expected that identical amounts of vanadium sulfate would induce different physiological responses in the sown species, with the expectation that such responses would be positive in direction, measurable, and statistically significant.

[0037] For planting, commercially available planting pots were used, which were filled with commercially available potting soil suitable for germination. Sowing was then carried out. Throughout the experiment, optimal air temperature (21-23 °C), relative humidity (53-55%), and light conditions corresponding to the natural habitat of the respective plants were maintained in a suitable building.

[0038] The experiments were conducted using the following numbers of plants: for common bean, 8 x 2 treated and the same number of untreated plants; for tomato and meadow sage, 8 x 4 treated and the same number of untreated plants; for white cabbage, 5 x 8 treated and the same number of untreated plants; and for onion, 8 x 8 treated and the same number of untreated plants. This corresponded to 8 treated and8 untreated planting pots per species, resulting in a total of 40 treated and 40 untreated pots, i.e. 80 test containers.

[0039] The seeds were of commercial origin and were untreated (not seed-dressed). The plants were sown at the species-specific optimal sowing depth and were immediately irrigated after sowing with 10 mm of irrigation water per test container. The untreated individuals subsequently received only the scheduled irrigation (10 mm of irrigation water per test container every third day after sowing). On the day following sowing, dissolved vanadium sulfate in dissociated form was applied to the soil by spraying, with a metallic vanadium content corresponding to 5 g / ha. Thereafter, the treated individuals also received only irrigation water, in a manner fully identical to the irrigation program applied to the untreated individuals. Due to differences in germination dynamics and individual growth intensity — resulting in exhaustion of the available growth space — measurements were performed after 14 days for all species except onion, for which measurements were performed on day 21. In all cases, measurements were carried out on entire plants with washed roots (after removal of dead seed coats, which in all cases were located above ground, in the case of common bean and onion).

[0040] The results by species were as follows:

[0041]

[0042] *UTC = untreated control

[0043] From the measurement results it is clearly apparent that, for all species, an increase in biomass can be detected and verified in the presence of dissociated vanadium ions, wherein the extent of the increase depends on the actual nitrogen demand of the given species, as well as on the age and phenological stage of the plant.

[0044] In all cases, the presence of vanadium exerted a positive effect on plant growth via soil nitrogen-fixing microorganisms, in accordance with the biological characteristics of the individual plant species. In the context of the present experiment, this meant that the presence of vanadium did not disturb the inherent nitrogen demand of the individual plants. For example, species with lower nitrogen demand did not become excessively nitrogen-demanding; a good example of this is tomato, which has virtually no nitrogen requirement during germination and exhibited only a 2.19% increase in biomass compared to the untreated control. In contrast, species with higher nitrogen demand utilized the available surplus extremely efficiently, as exemplified by common bean, whose biomass increased by 24.68% relative to the untreated control. The table clearly demonstrates that, in all other cases as well, a significant increase in biomass was measurable compared to the untreated control, namely 12.12% for meadow sage, 17.1% for white cabbage, and 22.58% for onion, in ascending order.Example 2: Investigations Aimed at Verifying the Site of the Catalytic Process

[0045] In a further experiment, the objective was to determine whether the catalytic effect of vanadium depends on the spatial location of the microbiome. Accordingly, in this experiment, vanadium ions were not applied exclusively to the soil, but also directly to the plants, meaning that vanadium in an appropriate form was applied to both the soil and the plants, spatially and temporally separated. This experiment focused on the germination-stimulating effect and on separate parameters of below-ground and aboveground biomass.

[0046] The experiment was carried out in four replicates, using untreated plants of the same species as controls, and a standard treatment was also included. The standard treatment consisted of a “classical” crop production practice, namely the application of a high dose of nitrogen fertilizer at sowing (400 kg / ha UTEC46). All selected species were high nitrogen-demand, agriculturally important arable crops. The selection criteria included the availability of information on symbiotic species (pea / Pisum sativum) as well as on non-root-nodule plants, as detailed below: a monocotyledonous species with fibrous root system (maize / Zea mays) and a dicotyledonous species with taproot system (sunflower / Helianthus annuus).

[0047] In this example, the commercially available planting pots and germination soil described in Example 1 were used. Throughout the experiment, optimal air temperature (21-23 °C), relative humidity (53-55%), and light conditions corresponding to the natural habitat of the plants were ensured in a suitable building. For each of the three species, three seeds were sown per container, in four replicates.

[0048] A total of six different treatments were applied (one untreated control, one standard treatment, one combined treatment, and three treatments using vanadium only). The treatments were as follows:

[0049] • UTC (untreated control)

[0050] • standard nitrogen fertilizer solution applied to the soil

[0051] • nitrogen fertilizer solution + dissociated vanadium applied to the soil

[0052] • dissociated vanadium applied to the soil

[0053] • dissociated vanadium applied to the soil + dissociated vanadium applied to the seedlings • dissociated vanadium applied to the seedlings

[0054] Thus, in each experiment, 12 commercially available, untreated seeds per species were sown. The plants were sown at the species-specific optimal sowing depth and immediately irrigated after sowing with 10 mm of irrigation water per test container. The untreated individuals subsequently received only the scheduled irrigation (10 mm of irrigation water per test container every third day after sowing). The standard treatment, i.e. the fertilizer, was also applied as a solution for optimization purposes, to the soil surface on the day following sowing. At the same time, vanadium corresponding to 5 g / ha was applied to the soil surface, as well as the soil -related steps required for the hybrid treatments (see treatments 3 and 5). Treatments 5 and 6 were applied on the seventh day after sowing, likewise at a vanadium rate corresponding to 5 g / ha.

[0055] Measurements were performed on the fourteenth day after sowing. Scheduled irrigation with clean water was, of course, ensured throughout the entire duration and area of the experiment. At the conclusion of the experiment, the germinated individuals were counted by species and by treatment. Thereafter — prior to the commencement of measurements — root washing was performed, and in the case of pea and sunflower, dead seed coats, which in all cases were located above ground, were removed. Subsequently, the above-ground and below-ground biomass of the plants was measured separately.The results:

[0056] Pea:

[0057]

[0058] *UTC = untreated control

[0059] Maize (corn):

[0060]

[0061] *UTC = untreated control

[0062] Sunflower:

[0063]

[0064] *UTC = untreated control

[0065] The experimental results demonstrate that, for all plant species tested, the application of vanadium at any time resulted in a biomass increase of more than 10% compared to the growth of untreated plants; moreover, in species characterized by more sensitive germination, this effect also applied to the stimulation of germination. It can therefore be stated that the application of vanadium provides expressly advantageous effects that are unexpected and surprising for the skilled person. This is further evidenced by the fact that the magnitude and timing of the positive effects differ among the investigated species, while at the same time these effects occur in all cases in a stable, unambiguous, and statistically significant manner.

[0066] The experiments suggest that pea, owing to its own nitrogen-fixing symbionts, exhibits the least pronounced response; however, even in this case, a remarkable increase in biomass was observed, particularly when catalytically active vanadium was made available immediately after sowing. Maize likewise responds more favorably to an early vanadium source, whereas sunflower exhibits the most pronounced response to later or combined application.Example 3: Investigation of the Applicability of Vanadium Seed Treatment (Seed Dressing) as an Agronomic Practice

[0067] In a third exploratory study, the applicability of vanadium as a seed-dressing agent was investigated. The experiments clearly demonstrated that vanadium applied in this manner is also capable of markedly improving plant physiological processes by providing additional nitrogen to the seedlings. In this case as well, vanadium improved the germination percentage, and the biomass of the seedlings visibly exceeded that of the untreated control. (Exact quantitative measurement was not possible in this case for several reasons, including the fact that seed-dressing agents themselves have mass and that the weights of the blotting papers were not equalized.)

[0068] During implementation, two methods were used to fix vanadium onto the seed surface. In one case, the stock solution of vanadium sulfate was added to a commercial seed-dressing formulation (Tebseme, 25 g / L tebuconazole; dose: 1.2 L per tonne of seed). In the other case, vanadium sulfate was added to a concentrated edible white crystalline sugar solution heated to 35 °C (water : sucrose = 1 : 2 m / m%), which was then cooled to room temperature. From this solution, 15 mL was sprayed — naturally by species and separately — onto the seeds, with repeated mixing to ensure uniform distribution. (The thousand-kernel weight of winter wheat — i.e. the mass of one thousand seeds of the same species — was 54.2 g, and each dressing formulation was applied to 500 g of seed; the thousand-kernel weight of winter oilseed rape was 4.7 g, and in this case each dressing formulation was applied to 50 g of seed.) In the seed-dressing treatments containing vanadium, an amount corresponding to 2.5-3 g of vanadium per tonne of seed was applied to the seed surfaces. In both cases, more uniform and more vigorous stands developed as a result of the treatments, with improved germination vigor.

[0069] For the experiments, commercially available blotting paper was used, which was moistened prior to use. Onto this blotting paper, 100 commercially available seeds per species and per treatment were placed and rolled for two major arable crops: one monocotyledonous species, winter wheat (Triticum aestivum), and one dicotyledonous species, winter oilseed rape (Brassica napus subsp. napus). The treatments included untreated, dressed, sugar-syrup-treated, dressed + vanadium, and sugar-syrup-treated + vanadium seeds. Throughout the experiment, optimal air temperature (21-23 °C), relative humidity (53-55%), and light conditions corresponding to the natural habitat of the plants were ensured in a suitable building. The experiment was evaluated on day 10.

[0070] The treatments were as follows:

[0071] • UTC (100 winter wheat and 100 winter oilseed rape seeds, untreated control)

[0072] • seed dressed (100 winter wheat and 100 winter oilseed rape seeds)

[0073] • seed treated with sugar syrup (100 winter wheat and 100 winter oilseed rape seeds)

[0074] • seed dressed with vanadium (100 winter wheat and 100 winter oilseed rape seeds)

[0075] • seed treated with sugar syrup and vanadium (100 winter wheat and 100 winter oilseed rape seeds)

[0076] Thus, a total of 500 winter wheat seeds and 500 winter oilseed rape seeds were examined, yielding the following results:

[0077]

[0078]

[0079] Example 4: Phytotoxicity Assessment

[0080] In this test, it was examined whether a drastic increase in vanadium content — by one order of magnitude compared to the previous experiments — would cause any negative physiological effects. For this purpose, one monocotyledonous crop species (maize / Zea mays) and one dicotyledonous crop species (sunflower / Helianthus annuus) were selected.

[0081] During the experiment, commercially available planting pots and germination soil were used. Throughout the experiment, optimal air temperature (21-23 °C), relative humidity (53-55%), and light conditions corresponding to the natural habitat of the plants were ensured in a suitable building. For each species, three seeds were sown per container, in five replicates. A total of two different test conditions were established (one untreated control and two vanadium -treated conditions).

[0082] The treatment protocol was as follows: immediately after sowing, irrigation was performed with 10 mm of irrigation water per test container. The untreated individuals subsequently received only the scheduled irrigation (10 mm of irrigation water per test container every third day after sowing). On the day following sowing, a vanadium sulfate solution containing 10 mol of vanadium per hectare (corresponding to approximately 510 g / ha of vanadium) was applied to the soil surface. Measurements were performed on the fourteenth day after sowing. Scheduled irrigation with clean water was, of course, ensured throughout the entire duration and area of the experiment.

[0083] At the conclusion of the experiment, the germinated individuals were counted by species and by treatment. Thereafter — prior to the commencement of measurements — root washing was performed, and in the case of sunflower, dead seed coats, which in all cases were located above ground, were removed. Subsequently, the total biomass formed by the plants was measured.

[0084]

[0085] UTC = untreated control

[0086] per 12 plants

[0087] per 13 plants

[0088] The data indicate that crop plants exhibit a very high tolerance even in cases of potential “overdosing” with vanadium, since their biomass is significantly greater than that of untreated plants, and the presence of vanadium also shows a consistent, positive effect on germination.

[0089] Summary

[0090] The results obtained in the examples clearly demonstrate that dissociated vanadium ions capable of undergoing valence changes are suitable for significantly catalyzing the fixation of atmosphericnitrogen, thereby enabling the substitution, reduction, or optimization of the demand for fertilizers that impose a substantial environmental burden.

[0091] In addition, the solution according to the invention provides not only a significant improvement compared to untreated control stands, but also achieves substantially better results than those obtained using currently applied high-dose nitrogen fertilizers. The experimental results confirmed that only a few grams of vanadium are capable of replacing or supporting fully synthetic nitrogen fertilizers produced with high energy input, or — when combined therewith — of exerting an even more pronounced effect.

[0092] The vanadium compounds applied according to the invention can make a significant contribution to improving nitrogen supply in non-tilled or reduced-tillage agricultural areas. Plants respond exceptionally well to the increased amounts of nitrogen provided via the catalytic effect, which nitrogen is fixed and utilized exclusively through biological pathways. As a natural element, this form of nitrogen supply is suitable for meeting the nitrogen requirements of biological, ecological, and nature -based farming systems, or for mitigating nitrogen deficiencies that may arise therein.

[0093] The invention provides a completely novel approach to satisfying the nitrogen requirements of plants, the essence of which lies in enhancing the nitrogen-fixing capacity of nitrogen-fixing microorganisms ubiquitously present in the biosphere. All advantages achievable by applying the solution according to the invention are realized in such a manner that all applications and methods disclosed herein comply with the strictest environmental and nature conservation guidelines. A further major advantage is that the solution can be used without difficulty in conventional, integrated, and organic farming systems alike. Compared to conventional methods for nitrogen supplementation, the method according to the invention is more advantageous, more economical, and more environmentally friendly. An additional significant advantage of the solution according to the invention is that it is non-selective with respect to both plants and atmospheric nitrogen-fixing microorganisms, meaning that it can be applied to any plant species and any microorganism, and no issues arise concerning transformative effects of applied microorganisms on the native microbiome.

Claims

CLAIMS1. Use of vanadium for enhancing the nitrogen-fixing capability of microorganisms capable of fixing atmospheric nitrogen.

2. The use according to claim 1, characterized in that the vanadium is applied in the form of a salt.

3. The use according to claim 2, characterized in that the vanadium is applied in the form of a salt dissociated in water.

4. The use according to claim 3, characterized in that the water-dissociated salt is vanadium sulfate in dehydrated or any hydrated form / VOSCUifbO); / . wherein x is an integer from 0 to 6.

5. A method for increasing the yield and biomass of plants, characterized in that vanadium is applied to the plant growth medium, to the plant, to both, and / or to the seed surface by seed dressing, thereby enhancing the nitrogen-fixing capability of microorganisms capable of fixing atmospheric nitrogen.

6. The method according to claim 5, characterized in that the vanadium is applied in the form of a salt.

7. The method according to claim 5, characterized in that the vanadium is applied in the form of a salt dissociated in water.

8. The method according to claim 5, characterized in that the water-dissociated salt is vanadium sulfate in dehydrated or any hydrated form / VOSCUiFbO) ; / . wherein x is an integer from 0 to 6.

9. The method according to any one of claims 5 to 8, characterized in that the vanadium is applied to one or more of the following: the plant growth medium, the plant, and the plant seed, wherein the application may be simultaneous or carried out at different times.

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