Patent Application
20240376022
The present invention relates to fertilizers comprising potassium and potassium solubilizing microorganisms. It also relates to methods of manufacturing these fertilizers and to uses of these fertilizers for providing nutrients to plants.
After nitrogen and phosphorus, potassium is one of the major nutrients required by all the plants. It plays a major role in the activation of several metabolic processes including protein synthesis, photosynthesis, enzyme activation, the transport of water and nutrients in the plants through xylem and synthesis of starch. It also plays a role in improving quality and shelf life of crops as well as resistance to stress and disease. It is often observed that without adequate potassium, the plants have poorly developed roots, grow slowly, produce small seeds and have lower yields.
Potassium in soil exists in different forms but the crop can absorb what is present in soil solution only. The readily available potassium in soil solution is just 2% out of the total, and the remaining part of soil potassium is locked up in soil minerals and hence most of it is unavailable for plant uptake. Also, in most of the soils, potassium levels decrease easily due to crop uptake, runoff, leaching and soil erosion.
Soil potassium management strategies primarily rely on the application of potassium fertilizers. A diverse group of potassium fertilizers exist, with notable examples being potassium thiosulfate and potassium sulfate which are available under brand names KTS®, GranuPotasse®, SoluPotasse®, K-Leaf® from Tessenderlo Kerley. Some potassium fertilizers are suitable for fertigation or foliar application, for example KTS® (which is a liquid) and SoluPotasse® and K-Leaf® (which are highly soluble forms of potassium sulfate, allowing dissolution for e.g. fertigation or spray application).
In recent years, soil potassium management strategies relying on the application of potassium solubilizing bacteria and other microorganisms (also interchangeably referred to as potassium mobilizing micro-organisms) as biofertilizer instead of direct application of potassium have emerged. A large number of saprophytic bacterial and fungal strains have been identified which solubilize potassium from insoluble forms like mica, fledspar and others by microbial production of protons and organic ligands, hydroxyl anions and extracellular polysaccharides (EPS), which can either directly dissolve rock potassium or chelate silicon ions to bring potassium into the solution.
Ali, A., et al. Archives of Agriculture Sciences Journal 2.2 (2019): 43-54 describes treatment of a plot of potato tubers with NPK fertilization in the form of superphosphate (applied during land preparation), urea (applied 30, 60 and 90 days after planting) and a mixture of feldspar, filter mud cake and potassium sulfate (applied 30, 60 and 90 days after planting). Potassium solubilizing bacteria Bacillus cereus was added after emergence of potato plants and once again after one week.
A disadvantage of known soil potassium management strategies employing potassium solubilizing microorganisms is that they rely on either (i) application of only the potassium solubilizing microorganism without applying a potassium fertilizer throughout the growing season, which limits use of this strategy to high potassium content soils and still results in very limited potassium availability for the crop (and thus low crop health benefits or yield increase); or (ii) separate applications of the potassium solubilizing microorganism and potassium fertilizer, leading to a complex application scheme requiring more interventions than a conventional NPK fertilization scheme, which is very labor intensive and thus costly.
It is an object of the present invention to provide products and methods which simplify and/or improve existing crop potassium management strategies, crop health, crop yield, etc.
The present inventors have surprisingly found that one or more objects of the invention is achieved by employing a high potassium content fertilizer which includes potassium solubilizing microorganisms, as described herein. Indeed, as is shown in the appended examples, it was found that it is possible for potassium solubilizing microorganisms to survive in the chemical environment provided by concentrated potassium fertilizers. This enables a convenient, shelf-life stable fertilizer to be provided and results in a surprising increase in crop health and performance characteristics, in particular yield and quality. The formulations described herein are particularly practical to use since they allow the fertilizer and the microorganisms to be applied simultaneously, as opposed to the known separate application modes which are more labor intensive, and the present formulation's high concentration reduces the number of applications of K fertilization required during the growing season. The fertilizers of the present invention also easily allow an even distribution of the potassium solubilizing microorganism over the whole application area to be achieved, which is difficult when applying potassium solubilizing microorganism alone because the required dose and thus amount of inoculum to be applied is very small. By using the potassium source as a carrier, the potassium solubilizing microorganism can be more accurately and evenly dosed. Without wishing to be bound by any theory, it is believed that the formulations of the present invention further synergystically improve performance over separate application of potassium solubilizing microorganisms and potassium fertilizers since they guarantee that the microorganism will be in close contact with potassium-bearing compounds, independent of potassium content of soils and distribution of that potassium content over different soil layers (e.g. microorganisms applied to the top soil do not easily access potassium formations in lower layers), and the close contact of the potassium solubilizing microorganisms and potassium fertilizers is believed to decrease the K-fixation rate of the applied potassium fertilizer (effectively slowing down conversion of the fertilizer to unavailable forms of potassium).
In a first aspect of the present invention there is provided a fertilizer comprising
In another aspect, the present invention provides a method for the preparation of a fertilizer as described herein comprising the steps of:
In another aspect, the present invention provides a method of fertilization comprising simultaneously applying a first source of potassium as described herein and a potassium solubilizing microorganism as described herein to soil and/or foliage, preferably to soil. In preferred embodiments, the simultaneous application of the first source of potassium and the potassium solubilizing microorganism is as the fertilizer of the present invention.
In another aspect, the present invention provides the use of the fertilizers of the invention:
In another aspect, the present invention provides a kit-of-parts comprising a first source of potassium as described herein; a potassium solubilizing microorganism as described herein; and instructions for combining the first source of potassium and the potassium solubilizing microorganism such that a fertilizer as described herein is obtained.
The expression “comprise” and variations thereof, such as, “comprises” and “comprising” as used herein should be construed in an open, inclusive sense, meaning that the embodiment described includes the recited features, but that it does not exclude the presence of other features, as long as they do not render the embodiment unworkable.
The expressions “one embodiment”, “a particular embodiment”, “an embodiment” etc. as used herein should be construed to mean that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of such expressions in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. For example, certain features of the disclosure which are described herein in the context of separate embodiments are also explicitly envisaged in combination in a single embodiment.
The singular forms “a,” “an,” and “the” as used herein should be construed to include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its broadest sense, that is as meaning “and/or” unless the content clearly dictates otherwise.
The expression “potassium (as K2O)” when used in relation to the potassium content is known to the skilled person and should be construed to mean the potassium content as expressed in terms of the amount of K2O which would provide the same amount of potassium as provided by whichever potassium source is actually contained in the fertilizer. For example, if the first source of potassium is potassium sulfate (which comprises 44.88 wt. % potassium) and the fertilizer comprises 85 gram potassium sulfate per 100 g of fertilizer, then the fertilizer comprises the first source of potassium in an amount providing 38.15 wt. % potassium (by total weight of the fertilizer), which is typically expressed in the art and throughout this document as 45.8 wt. % (by total weight of the fertilizer) potassium (as K2O). The wt. % potassium can be converted to the wt. % potassium (as K2O) by multiplication with the factor 1.2.
The expression “liquid” as used herein should be construed to encompass slurries and pastes, unless otherwise specified.
In a first aspect of the present invention there is provided a fertilizer comprising
In preferred embodiments of the invention, the first source of potassium is selected from the group consisting of potassium sulfate (K2SO4), potassium bisulfate (KHSO4), potassium thiosulfate (K2S2O3), dipotassium sulfite (K2SO3) potassium bisulfite (KHSO3), potassium chloride (KCl), potassium magnesium sulfate (K2SO4·2MgSO4), potassium nitrate (KNO3), potassium sodium nitrate KNa(NO3)2, potassium hydroxide (KOH), potassium carbonate (K2CO3KHCO3), potassium orthophosphate KH2PO4K2HPO4, potassium polyphosphate (K4P2O7), potassium metaphosphate (KPO3), polyhalite (K2Ca2Mg(SO4)4·2H2O), langbeinite (K2Mg2(SO4)3), kainite (KMg(SO4)·Cl·3H2O), picromerite (K2SO4·MgSO4·6H2O), leonite (K2SO4·MgSO4·4H2O), aphthitalite (K3Na(SO4)2), K-feldspar minerals (e.g. orthoclase, microcline, sanidine, adularia, and/or amazonite), feldspathoid minerals (e.g. nepheline, leucite), K-bearing phyllosilicates (e.g. illite) and combinations thereof. More preferably the first source of potassium is selected from the group consisting of potassium sulfate (K2SO4), potassium bisulfate (KHSO4), potassium thiosulfate (K2S2O3), dipotassium sulfite (K2SO3) potassium bisulfite (KHSO3), potassium magnesium sulfate (K2SO4·2MgSO4), polyhalite (K2Ca2Mg(SO4)4·2H2O), langbeinite (K2Mg2(SO4)3), K-feldspar minerals (e.g. orthoclase, microcline, sanidine, adularia, and/or amazonite), feldspathoid minerals (e.g. nepheline, leucite), K-bearing phyllosilicates (e.g. illite) and combinations thereof. Still more preferably the first source of potassium is selected from the group consisting of potassium sulfate (K2SO4), potassium bisulfate (KHSO4), potassium thiosulfate (K2S2O3), potassium magnesium sulfate (K2SO4·2MgSO4), polyhalite (K2Ca2Mg(SO4)4·2H2O), langbeinite (K2Mg2(SO4)3) and combinations thereof. Most preferably the first source of potassium is potassium sulfate (K2SO4) or potassium thiosulfate (K2S2O3).
It is also preferred that the fertilizer of the invention comprises less than 5 wt. % (by total weight of the fertilizer), preferably less than 2 wt. %, more preferably less than 0.5 wt. % of carboxylic acid salts of potassium. In some embodiments of the invention, the fertilizer is substantially free of carboxylic acid salts of potassium.
In preferred embodiments of the invention, the first source of potassium is provided in an amount providing more than 15 wt. % (by total weight of the fertilizer) potassium (as K2O), preferably more than 20 wt. %, more preferably more than 25 wt. %. In some embodiments of the invention, preferably when the fertilizer is provided in solid form, the first source of potassium is preferably provided in an amount providing more than 28 wt. % (by total weight of the fertilizer) potassium (as K2O), preferably more than 32 wt. %, preferably more than 36 wt. %. In particularly preferred embodiments of the invention, preferably when the fertilizer is provided in solid form, the first source of potassium is provided in an amount providing more than 40 wt. % (by total weight of the fertilizer) potassium (as K2O), preferably more than 45 wt. %, more preferably more than 48 wt. %, most preferably more than 49%.
The total amount of potassium (as K2O) in the fertilizer is typically less than 62 wt. % (by total weight of the fertilizer), preferably less than 55 wt. %, more preferably less than 53%.
In some embodiments of the invention the fertilizer comprises one or more further sources of potassium next to the first source of potassium. In case the fertilizer comprises one or more further sources of potassium (e.g. from organic sources such as compost or manure), it is preferred that such other sources of potassium are comprised in the fertilizer in an amount providing less than 10 wt. % (by total weight of the fertilizer) potassium (as K2O), preferably less than 5 wt. %.
In preferred embodiments of the invention, the amount of chloride (Cl−) in the fertilizer is less than 5 wt. % (by total weight of the fertilizer), more preferably less than 3 wt. %.
In preferred embodiments of the invention, the amount of sulfite (SO3) in the fertilizer is less than 3 wt. % (by total weight of the fertilizer), more preferably less than 1 wt. %.
In an embodiment of the invention, the potassium solubilizing microorganism is selected from microorganisms which display a halo zone after 72 hours when tested in accordance with the protocol defined in Rajawat, Mahendra Vikram Singh, et al. “A modified plate assay for rapid screening of potassium-solubilizing bacteria.” Pedosphere 26.5 (2016): 768-773 (which reference is incorporated herein in its entirety), employing the modified Aleksandrov medium with BTB at 100 mg/I.
In preferred embodiments of the invention the potassium solubilizing microorganism is selected from the genera Achromobacter, Acidithiobacillus, Alcaligenes, Agrobacterium, Aminobacter, Arthrobacter, Aspergillus, Azospirillum, Azotobacter, Bacillus, Bradyrhizobium, Brevibacillus, Brevundimonas, Burkholderia, Buttiauxella, Chryseobacterium, Citrobacter, Cladosporium, Clostridium, Colletotrichum, Delftia, Enterobacter, Ensifer, Erwinia, Escherichia, Exiguobacterium, Glomus, Frateuria, Flavobacterium, Flectobacillus, Fusarium, Janthinobacterium, Klebsiella, Kluyvera, Kocuria, Lactobacillus, Leclercia, Macrophomina, Mesorhizobium, Methylobacterium, Microbacterium, Myroides, Paenibacillus, Pantoea, Penicillium, Pseudomonas, Pusillimonas, Rahnella, Ralstonia, Rhizobium, Rhizoctonia, Salmonella, Sclerotinia, Schizophyllum, Serratia, Sphingobacterium, Sphingomonas, Stenotrophomonas, Staphylococcus, Thiobacillus, Trichoderma, and combinations thereof, preferably the potassium solubilizing microorganism is selected from the genera Bacillus, Frauteria, Pseudomonas, and combinations thereof, more preferably the potassium solubilizing microorganism is selected from the genera Bacillus and/or Pseudomonas. Suitable species of microorganisms within these genera are known to the skilled person and are for example listed on pages 181-185 of Kour, Divjot, et al. “Potassium solubilizing and mobilizing microbes: biodiversity, mechanisms of solubilization, and biotechnological implication for alleviations of abiotic stress.” New and Future Developments in Microbial Biotechnology and Bioengineering. Elsevier, 2020. 177-202, incorporated herein by reference.
In preferred embodiments of the invention the potassium solubilizing microorganism is one or more species selected from the group consisting of Achromobacter piechaudii, Acidithiobacillus ferrooxidans, Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Agrobacterium radiobacter, Agrobacterium rubi, Agrobacterium tumefaciens, Alcaligenes piechaudii, Aspergillus awamori, Aspergillus candidus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus glabrum, Aspergillus niger, Aspergillus terreus, Aspergillus wentii, Azospirillum brasilense, Azospirillum lipoferum, Azotobacter chroococcum, Bacillus altitudinis, Bacillus amyloliquefaciens, Bacillus cereus, Bacillus circulans, Bacillus circulanscan, Bacillus coagulans, Bacillus edaphicus, Bacillus firmus, Bacillus flexus, Bacillus globisporus, Bacillus horikoshii, Bacillus licheniformis, Bacillus megaterium, Bacillus methylotrophicus, Bacillus mojavensis, Bacillus mucilaginosus, Bacillus mycoides, Bacillus pasteurii, Bacillus pseudomycoides, Bacillus subtilis, Bacillus thuringiensis, Burkholderia cepacia, Burkholderia glathei, Burkholderia mallei, Burkholderia metallica, Burkholderia pyrrocinia, Burkholderia pyrrocinia, Burkholderia ubonensis, Buttiauxella izardii, Citrobacter Freundii, Clostridium botulinum, Clostridium pasteurianum, Delftia acidovorans, Ensifer adhaerens, Enterobacter aerogenes, Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter cloacae, Enterobacter hormaechei, Erwinia amylovora, Escherichia freundii, Exiguobacterium antarcticum, Flavobacterium johnsoniae, Frateuria aurantia, Fusarium mosseae, Fusarium oxysporium, Fusarium solani, Glomus coronatum, Glomus diaphanum, Glomus etunicatum, Glomus intraradices, Glomus mosseae, Glomus viscosum, Klebsiella variicola, Kocuria rhizophila, Leclercia adecarboxylata, Macrophomina phaseolina, Methylobacterium mesophilicum, Methylobacterium nodulans, Microbacterium foliorum, Microbacterium hominis, Microbacterium testaceum, Myroides odoratimimus, Paenibacillus anaericanus, Paenibacillus glucanolyticus, Paenibacillus kribensis, Paenibacillus mucilaginosus, Pantoea agglomerans, Pantoea ananatis, Penicillium frequentans, Pseudomonas aeruginosa, Pseudomonas azotoformans, Pseudomonas brassicacearum, Pseudomonas chlororaphis, Pseudomonas fluorescens, Pseudomonas korensis, Pseudomonas oryzihabitans, Pseudomonas pseudoalcaligenes, Pseudomonas putida, Pseudomonas taiwanensis, Pseudomonas trivalis, Pseudomonas vancoverencis, Pusillimonas agarexedens, Pusillimonas alkaliterrae, Pusillimonas glucanolyticus, Pusillimonas harena, Rahnella aquatilis, Ralstonia pickettii, Rhizobium leguminosarum, Rhizobium pusense, Rhizoctonia solani, Rizophagus intraradices, Salmonella bongori, Schizophyllum commune, Sclerotinia sclerotiorum, Serratia marcescens, Stenotrophomonas maltophilia, Thiobacillus denitrificans, Trichoderma harzianum, and combinations thereof. In more preferred embodiments of the invention the potassium solubilizing microorganism is selected from the group consisting of Pseudomonas vancoverencis, Pseudomonas korensis, Pseudomonas putida, Pantoea agglomerans, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus subtilis, Bacillus mucilaginosus, Frateuria aurantia, and combinations thereof. In the most preferred embodiments of the invention the potassium solubilizing microorganism comprises or is Bacillus mucilaginosus. In preferred embodiments of the invention, the potassium solubilizing microorganism is in the form of spores or cysts.
It is explicitly envisaged that the potassium solubilizing microorganism may be provided in the form of two or more different species of potassium solubilizing microorganisms as described herein, for example a combination of Pseudomonas vancoverencis, Pseudomonas korensis.
The fertilizer of the invention typically comprises at least 1×103 CFU/g (by total weight of the fertilizer), more preferably at least 1×104 CFU/g, most preferably at least 1×105 CFU/g of the potassium solubilizing microorganism. The invention is not particularly limited with respect to the upper limit of the amount of potassium solubilizing microorganism comprised in the fertilizer. For cost-efficiency reasons, the amount will typically be within the range of 1×103 to 1×1012CFU/g (by total weight of the fertilizer), preferably within the range of 1×104 to 1×1010 CFU/g, most preferably within the range of 1×105 CFU/g to 1×109 CFU/g.
As shown in the appended examples, the present inventors have surprisingly shown that the potassium mobilizing microorganisms can survive in the fertilizer of the invention even upon prolonged storage. Hence, in preferred embodiments of the invention, the fertilizer as described herein is storage stable. Storage stable preferably means that the fertilizer complies with CFU30>0.01*CFU0 wherein CFU0 is the number of viable microorganisms expressed as CFU/g (by total weight of the fertilizer) provided in the fertilizer at time of its formulation (day 0), and CFU30 is the number of viable microorganisms expressed as CFU/g (by total weight of the fertilizer) determined at day 30, wherein the fertilizer is stored in the dark, in a sealed container at 25° C. Preferably, the fertilizer complies with CFU30>0.1*CFU0, more preferably the fertilizer complies with CFU30>0.5*CFU0. In other words, the CFU/g (by total weight of fertilizer) determined after thirty days of storage is more than 1% of the CFU/g at day zero, preferably more than 10%, more preferably more than 50%.
The fertilizer may be provided in the form of a solid or a liquid. Providing the fertilizer as a solid is particularly preferably when the first source of potassium is selected from the group consisting of potassium sulfate (K2SO4), potassium magnesium sulfate (K2SO4·2MgSO4), polyhalite (K2Ca2Mg(SO4)4·2H2O), langbeinite (K2Mg2(SO4)3) and combinations thereof. Providing the fertilizer as a liquid is particularly preferably when the first source of potassium is (a) potassium thiosulfate or (b) dipotassium sulfite (K2SO3) and/or potassium bisulfite (KHSO3).
In preferred embodiments of the invention, the fertilizer is provided in the form of a particulate solid. The type of particles is not particularly limited and can be, for example, a powder, granule, prill, pellet or pastille. In highly preferred embodiments, the first source of potassium and the potassium solubilizing microorganism are comprised in the same particle (as opposed to e.g. a simple dry blend of inoculum and a potassium source). This has the additional advantage that the product is delivered as a “ready to use” product such that dosing mistakes are avoided and supply chain is simplified compared to on-site blending at the grower site. The invention is not particularly limited with regard to the location of the potassium solubilizing microorganism with respect to the other ingredients of the fertilizer within a particle. Hence, the particle comprising the first source of potassium and the potassium solubilizing microorganism can be any type of agglomerate (e.g. an optionally coated granule, pellet, prill, pastille, etc.) or coated powder. The present inventors have found that embodiments of the invention wherein the potassium solubilizing microorganism is coated on the outside of the fertilizer particles are preferable since such coated particles are conveniently and easily obtainable by spraying an aqueous solution of microorganism on fertilizer particles. Alternatively the potassium solubilizing microorganism may be present in the core of an optionally multi-layered core-shell type particle, or as an intermediate layer of a multi-layered particle, or homogenously distributed throughout the fertilizer particle.
In some embodiments of the invention, the fertilizer is provided in the form of a powder having a particle size distribution wherein >80 wt. % of the powder passes through a sieve with a 1.65 mm aperture, preferably >75 wt. % passes through a sieve with 0.3 mm aperture. This particle distribution is useful in case a fast-dissolving fertilizer is desired. In alternative embodiments of the invention, the fertilizer is provided in the form of granules wherein >90 wt. % of the granules has a diameter between 0.5 and 10 mm, preferably between 1 and 6 mm. These granules are easy to handle and apply to the field.
In some embodiments of the invention the fertilizer is provided in the form of a particulate solid, wherein the fertilizer has a solubility of more than 100 g/I demineralized water (25° C.). In such embodiments it is preferred that the pH of a 1 wt. % solution of the fertilizer in demineralized water is within the range of 2.5-6, preferably 2.5-4, more preferably 2.6-3.4. In such embodiments the first source of potassium is preferably potassium sulfate (K2SO4). These potassium sulfate fertilizers are suitable to dissolve and apply as liquid fertilizer, for example via spray, injection or fertigation application. Potassium solubilizing microorganisms which are particularly preferred for these fertilizers are Bacillus mucilaginosus and Bacillus subtilis. As shown in the appended examples, the present inventors have demonstrated the exceptional stability of these microorganisms in the liquid fertilizers of the present invention. This is important since the liquid fertilizer is often stored in tanks next to the field over a number of days which can cause a significant reduction in the number of viable microorganisms. Surprisingly, despite the acidic pH, stable compositions according to the invention could be provided. This is advantageous since this allows the typical “fertilizer grade” potassium sulfate obtained from a Mannheim process to be used. Mannheim-produced potassium sulfate contains, next to the potassium sulfate, minor amounts of acidic impurities which cause a low pH upon dissolution. Such a potassium sulfate is available from Tessenderlo Kerley under the name SoluPotasse®. Hence, in some embodiments of the invention the fertilizer is provided in the form of a particulate solid having a solubility of more than 100 g/I demineralized water (25° C.), wherein the first source of potassium is Mannheim-produced potassium sulfate (K2SO4), wherein the pH of a 1 wt. % solution of the fertilizer in demineralized water is within the range of 2.5-6, preferably 2.5-4, more preferably 2.6-3.4, and wherein the potassium solubilizing microorganism is preferably selected from the group consisting of Bacillus mucilaginosus, Bacillus subtilis and combinations thereof.
In some embodiments of the invention the fertilizer is provided in the form of a liquid, wherein the fertilizer has a pH within the range of 5.5-9, preferably 6-9, more preferably 6.5-8.8. In such embodiments the first source of potassium is preferably potassium thiosulfate (K2S2O3). These potassium thiosulfate fertilizers are storage stable and can be applied as liquid fertilizer, for example via spray, injection or fertigation application. Potassium solubilizing microorganisms which are particularly preferred for liquid fertilizers according to the invention are from the genus Bacillus, in particular Bacillus mucilaginosus, Bacillus amyloliquefaciens and Bacillus subtilis. As shown in the appended examples, the present inventors have demonstrated the exceptional stability of these microorganisms in the liquid fertilizers of the present invention.
In some embodiments there is provided the fertilizer of the present invention wherein:
In some embodiments there is provided the fertilizer of the present invention wherein:
In some embodiments there is provided the fertilizer of the present invention wherein:
The fertilizer of the present invention may optionally comprise further ingredients next to the first source of potassium and the potassium solubilizing microorganism, such as (but not limited to) solvent (e.g. water), other fertilizing ingredients, other microorganisms (e.g. other potassium solubilizing microorganisms or plant growth promoting microorganisms), surface active compounds, pH adjusting agents (strong or weak acids or bases), biostimulants (e.g. amino acids or peptides), carriers (e.g. silicates, clays, sugars) etc.
Examples of other fertilizing ingredients such as may be included in the fertilizer of the present invention include a source of macronutrients selected from N, P, S, Ca, or Mg and/or a source of micronutrients selected from Fe, B, Mn, Zn, Cu, Mo, Ni, V, Co.
In specific embodiments of the invention, the fertilizer comprises more than 80 wt. % (by dry weight of the fertilizer) of the first source of potassium, preferably more than 90 wt. %, more preferably more than 92 wt. %. As will be understood by the skilled person, when reference is made throughout this document to the amount of the first source of potassium, this refers to the amount of the compound inclusive of its counterion unless specified otherwise. For example, if the first source of potassium is potassium sulfate and the fertilizer comprises 85 g potassium sulfate per 100 g dry weight of fertilizer, then the fertilizer comprises 85 wt. % (by dry weight of the fertilizer) of the first source of potassium.
In some embodiments of the invention, the fertilizer consists essentially of the first source of potassium, the potassium solubilizing microorganism, and optionally water.
In another aspect, the present invention provides a method for the preparation of a fertilizer as described herein comprising the steps of:
As will be understood by the skilled person, all embodiments described herein for the fertilizer of the invention, for example relating to the identity and concentrations of the different components, or the stability of the resulting product are equally applicable to the method for the preparation of the fertilizer.
In preferred embodiments of the invention, the fertilizer is a particulate solid wherein the first source of potassium and the potassium solubilizing microorganism are comprised in the same particle and step (iii) is performed via spray coating, dip coating, brushing, roll coating, co-extruding, co-granulating, or co-pelletizing.
The invention also provides the fertilizer obtainable by the method described herein for the preparation of a fertilizer.
In another aspect, the present invention provides a method of fertilization comprising simultaneously applying a first source of potassium as described herein and a potassium solubilizing microorganism as described herein to soil and/or foliage, preferably to soil. In preferred embodiments, the simultaneous application of the first source of potassium and the potassium solubilizing microorganism is as the fertilizer of the present invention.
As will be understood by the skilled person, all embodiments described herein for the fertilizer of the invention, for example relating to the identity and concentrations of the different components, or the stability of the resulting product are equally applicable to the method of fertilization.
The application can take place at any time before, during or after the growing season. In case of annual crops it is preferred that the application takes place within 4 weeks prior to planting, such as about 2 weeks prior to planting.
The application can take place using any application method, such as broadcast or topdress application, sidedress application, banding, spray application, soil injection or fertigation.
In case the fertilizer of the invention is provided in the form of a granule, prill, pastille or pellet, it is typically applied as such to the soil via broadcasting, although other fertilizers or additives may be blended with the fertilizer of the invention before its application to the soil.
In case the fertilizer of the invention is provided in the form of a powder, the method typically comprises dissolving and/or suspending, preferably dissolving the fertilizer in water before application to the field via spray application, soil injection, banding or fertigation. The fertilizer is typically applied in dissolved form as such, although other fertilizers or additives may be blended with the solution or suspension of the fertilizer of the invention before its application to the soil.
In case the fertilizer of the invention is provided in the form of a liquid, the method typically comprises dilution of the fertilizer with water before application to the field via spray application, banding, soil injection or fertigation. In case of fertigation, dilution typically happens in-situ during application by slowly injecting the liquid fertilizer into a system actively irrigating water. The fertilizer is typically applied in diluted form as such, although other fertilizers or additives may be blended with the diluted fertilizer of the invention before its application to the soil.
The method of fertilization preferably comprises application of the first source of potassium in an amount within the range of 10-2000 kg potassium (as K2O) per hectare. The actual dose required depends on local growing conditions including, but not limited to soil type, soil potassium content, crop variety, target yield, etc. For example, mango typically requires about 10-100 kg potassium (as K2O) per hectare while banana typically requires about 1300-1500 kg potassium (as K2O) per hectare. It is within the routine capabilities of the skilled person to optimise the actual amount of potassium applied.
In some preferred embodiments, there is provided the method of fertilization wherein the method is for improving the morphological characteristics, the physiological characteristics and/or the yield of tomato crop. In particular, the method is for improving the morphological characteristics, the physiological characteristics and/or for increasing the yield of tomato crop compared to an identical fertilization scheme wherein no microorganism is applied. In preferred embodiments, the method is for increasing the yield of tomato crop by at least 5% compared to an identical fertilization scheme wherein no microorganism is applied, preferably by at least 7%, more preferably by at least 10%.
In some preferred embodiments, there is provided the method of fertilization wherein the method is for increasing the starch content, the yield, and/or the average tuber size of potato crop. In particular, the method is for increasing the starch content, the yield, and/or the average tuber size of potato crop compared to an identical fertilization scheme wherein no microorganism is applied. In preferred embodiments, the method is for increasing the yield of potato crop by at least 5% compared to an identical fertilization scheme wherein no microorganism is applied, preferably by at least 10%, more preferably by at least 14%.
In another aspect, the present invention provides the use of the fertilizers of the invention:
In preferred embodiments of the present invention there is provided the use of the fertilizers of the invention for improving the morphological characteristics, preferably of tomato crop, wherein the morphological characteristic is selected from fruit size, fruit weight, leaf area and/or uniformity of color.
In preferred embodiments of the present invention there is provided the use of the fertilizers of the invention for improving the physiological characteristics, preferably of potato or tomato crop, wherein the physiological characteristic is selected from firmness, fruit vitamin C content and/or shelf-life.
In highly preferred embodiments of the present invention there is provided the use of the fertilizers of the invention for improving the vitamin C content and/or the lycopene content of a crop, preferably a tomato crop. The vitamin C content and/or the lycopene content is preferably increased in the fruit of the crop, preferably the tomato crop. The vitamin C content is preferably increased by at least 20% and the lycopene content is preferably increased by at least 50%. The increase is preferably determined compared to an identical fertilization scheme wherein no microorganism is applied. As is shown in the appended examples, the present inventors have found that the concentration of vitamin C and lycopene in tomatoes is significantly increased compared to a control when employing the fertilizer of the invention.
In some embodiments, there is provided the use of the fertilizers of the invention for increasing the yield of tomato crop by at least 5% compared to an identical fertilization scheme wherein no microorganism is applied, preferably by at least 7%, more preferably by at least 10%. In preferred embodiments, the use is for increasing the yield of potato crop by at least 5% compared to an identical fertilization scheme wherein no microorganism is applied, preferably by at least 10%, more preferably by at least 14%.
The use preferably comprises application of the fertilizer of the present invention as is described herein in the context of the method of fertilization.
In another aspect, the present invention provides a kit-of-parts comprising a first source of potassium as described herein; a potassium solubilizing microorganism as described herein; and instructions for combining the first source of potassium and the potassium solubilizing microorganism such that a fertilizer as described herein is obtained.
As will be understood by the skilled person, all embodiments described herein for the fertilizer of the invention, for example relating to the identity and concentrations of the different components, or the stability of the resulting product are equally applicable to the kit-of-parts.
As will have been understood based on the above description, particularly preferred embodiments of the invention are described by the following items.
The effect of simultaneous fertilization of a potassium source and potassium solubilizing microorganisms on tomato was investigated.
A potassium sulfate (brand name SoluPotasse®) obtained from Tessenderlo Kerley was simultaneously applied with Pseudomonas vancoverencis and Pseudomonas korensis. The potassium sulfate had the following characteristics (before blending):
Tomato (Var. Hirad) was planted in sandy loam soil (soil K content=70 ppm) in 15 kg pots in a greenhouse and drip irrigation applied under normal watering conditions. Potassium sulfate and an inoculum powder of Pseudomonas vancoverencis and Pseudomonas korensis were simultaneously applied to the soil at a rate of 126 kg and 300 g per hectare respectively in 3 split applications during flowering, fruit set and fruit development (plus all fertilizers received by control). The control consisted of regular NP fertilizer (15:5) and micro fertilizer applied daily until the end of harvest, as well as potassium sulfate (SoluPotasse®) fertilizer applied once a week at total rate of 600 kg/ha (which was partially substituted for 126 kg Potassium sulfate applied simultaneously with microorganism for three applications of the test pots). The resulting tomatoes were evaluated for morphological traits and physiological traits according to the principal component analysis and factor analysis using STATISTICA 8.0 software.
The results are shown in the below table:
Simultaneous application of a potassium source and potassium solubilizing microorganisms resulted in significant increases in morphological parameters (such as firmness and even ripening), physiological parameters (such as leaf K content, fruit Vitamin C content, fruit Lycopene content) and yield of the tomatoes compared to the control treatment employing a corresponding fertilization scheme without potassium solubilizing bacteria.
Pure potassium sulfate powder (brand name SoluPotasse®) obtained from Tessenderlo Kerley and having the characteristics described in example 1 was dry blended with potassium solubilizing microorganism at a concentration of 1×107 CFU per 100 g fertilizer, 5×107 CFU per 100 g fertilizer, 1×108 CFU per 100 g fertilizer and 2×108 CFU per 100 g fertilizer. A 10% solution (in demi water) of the mixtures was prepared and stored at room temperature in the shade in a closed vessel. A sample of the solution was taken every day for a month, and plated onto a sterile NB (Nutrient Broth) growth medium in a Petri dish, which was incubated (24-48 hour) and submitted to a colony count in order to assess the survival of the tested microorganisms in the potassium sulfate solution.
The following potassium solubilizing microorganisms were tested: Pseudomonas korensis, Pseudomonas vancoverencis, Pseudomonas putida, Pantoea agglomerans, and Bacillus subtilis.
It was found that the number of viable colonies in the Bacillus subtilis samples remained stable up until at least a month, while the number of viable colonies was already decreased significantly after 24 hours for the other microorganisms. It was demonstrated that when microorganisms from the genus Bacillus are used, such as Bacillus subtilis, the shelf-life in dissolved solution remained stable. This is an important practical advantage since in practice the dissolved fertilizer may be stored in tanks for a number of days, e.g. during prolonged fertigation application.
Each of Pseudomonas korensis, Pseudomonas vancoverencis, Pseudomonas putida, Pantoea agglomerans, and Bacillus subtilis was dry blended with granular potassium sulfate (brand name GranuPotasse®) at concentrations of 1×107CFU per 100 g fertilizer, 5×107 CFU per 100 g fertilizer, 1×108 CFU per 100 g fertilizer and 2×108 CFU per 100 g fertilizer. The granular potassium sulfate had the following characteristics (before blending):
Each of the resulting 20 solid samples was stored at room temperature in the shade in a closed vessel. for 24 hours.
A sample of the dry product was taken every day for a month, dissolved and plated onto a sterile NB (Nutrient broth) growth medium in a Petri dish, which was incubated (24-48 hour) and submitted to a colony count in order to assess the survival of the tested microorganisms in the potassium sulfate solution.
It was found that all microorganisms maintained their initial CFU count after 24 hours of storage.
Hence, the stability of the fertilizers according to the invention has been demonstrated.
The effect simultaneous fertilization of a potassium source and potassium solubilizing microorganisms on potato variety Taros was investigated on a 2000 m2 plot divided into a control and test plot with a soil potassium content of 500 ppm.
Granular potassium sulfate (brand name GranuPotasse®) obtained from Tessenderlo Kerley and having the characteristics described in example 3 was dry blended with 1×107 CFU per 100 g fertilizer of a blend of Pseudomonas vancoverencis and Pseudomonas korensis to provide a fertilizer according to the present invention.
A control plot was treated according to regular local practices including pre-planting fertilization, fertilization during the growing season, and weed control. The GranuPotasse® was applied at a rate of 250 kg/ha two weeks prior to planting.
A test plot was treated identical to the control, however instead of GranuPotasse®, the fertilizer according to the invention was applied at the same potassium rate.
The results are shown in the following table.
Application of the fertilizer according to the present invention resulted in significant increases in yield, marketable yield, starch content, and leaf potassium content of the potatoes compared to a control treatment employing a corresponding fertilization scheme without potassium solubilizing bacteria.
The effect of simultaneous fertilization of a potassium source and potassium solubilizing microorganisms on the starch content and leaf potassium content of potato variety Banba was investigated on a 2500 m2 plot divided into a control and test plot with a soil potassium content of 275 ppm.
Granular Potassium sulfate (brand name GranuPotasse®) obtained from Tessenderlo Kerley and having the characteristics described in example 3 was dry blended with 1×107 CFU per 100 g fertilizer of a blend of Pseudomonas vancoverencis and Pseudomonas korensis to provide a fertilizer according to the present invention.
A control plot was treated according to regular local practices including pre-planting fertilization, fertilization during the growing season, and weed control. The GranuPotasse® was applied at a rate of 250 kg/ha (according to farmer practices) two weeks prior to planting. Tuber planting was done in June 2020 and the irrigation was performed between 4-8 day intervals, depending on the summer time temperature. Leaf analysis was done by obtaining approximately 500 g leaves (mid-size) of the plants which was immediately sent to laboratory for leaf analysis.
A test plot was treated identical to the control, however instead of GranuPotasse®, the fertilizer according to the invention was applied at the same potassium rate.
The results are shown in the following table.
Application of the fertilizer according to the present invention resulted in significant increases in starch content and leaf potassium content of the potatoes compared to a control treatment employing a corresponding fertilization scheme without potassium solubilizing bacteria.
In order to evaluate the stability of the fertilizers of the present invention, the following fertilizers 1-8 were prepared. The fertilizers 1-8 were stored at room temperature in the shade in a closed vessel that was opened periodically to sample the fertilizer to assess the survival of the tested microorganisms in the potassium fertilizer.
Every week for a month, then every month a sample (after dissolution for solid samples) was plated onto a sterile NB (Nutrient Broth) growth medium in a Petri dish, which was incubated (24-48 hour) and submitted to a colony count in order to assess the survival of the tested microorganisms in the potassium sulfate solution. The results are shown in the below table.
Bacillus subtilis
Bacillus subtilis
Bacillus subtilis
Bacillus subtilis
Bacillus
mucilaginous
Bacillus
mucilaginous
Bacillus
mucilaginous
Bacillus
mucilaginous
The GranuPotasse® had the characteristics (before coating) described in example 3, the SoluPotasse® had the characteristics (before coating) described in example 1. The KTS® is a solution of potassium thiosulfate in water which had the following characteristics (before blending):
It was found that the fertilizers according to the invention demonstrate excellent stability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21200479.0 | Oct 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/077307 | 9/30/2022 | WO |
