阅读说明：本技术 NPK-Si-腐殖酸盐肥料、其生产方法和用途 (NPK-Si-humate fertilizer, method for the production thereof and use thereof ) 是由 T.S.汉森 M.达斯托尔 O.斯克格博 V.马尔琴科夫 于 2018-11-20 设计创作，主要内容包括：本申请涉及一种组合有机矿物NPK-Si-腐殖酸盐肥料,所述肥料含有包含至少一种氮、磷或钾的营养化合物的至少一种颗粒矿物NPK肥料；和包含单硅酸-腐殖酸盐化合物的螯合物的颗粒腐殖质基硅肥料。本申请还涉及所述组合有机矿物NPK-Si-腐殖酸盐肥料的生产方法。(The present application relates to a combined organomineral NPK-Si-humate fertilizer containing at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium; and a granular humic silicon fertilizer comprising a chelate of a monosilicic acid-humate compound. The application also relates to a method for producing said combo-organomineral NPK-Si-humate fertilizer.)

1. A combination organomineral NPK-Si-humate fertilizer containing at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium; and a granular humic silicon fertilizer comprising a chelate of a monosilicic acid-humate compound.

2. The combination organomineral NPK-Si-humate fertilizer of claim 1, wherein the ratio of the at least one particulate mineral NPK fertilizer to the particulate humic silicon fertilizer is from 10:90 to 90:10 based on the total dry weight of at least one nitrogen, phosphorus or potassium nutrient compound and humic silicon fertilizer contained in the at least one NPK fertilizer.

3. The combination organomineral NPK-Si-humate fertilizer of claim 2, wherein the ratio of the particulate mineral NPK fertilizer to the humic based silicon fertilizer is from 20:80 to 80:20 based on the total dry weight of at least one nitrogen, phosphorus or potassium nutrient compound and humic based silicon fertilizer contained in the at least one NPK fertilizer.

4. The combination organomineral NPK-Si-humate fertilizer of any one of claims 1 to 3, wherein the mineral NPK fertilizer contains at least one of the following nutrient compounds:

(a) nitrogen (N) in the form of Nitrate (NO)₃ ^-) Ammonium (NH)₄ ⁺) And/or urea (CO (NH)₂)₂)，

(b) Phosphorus (P) in the form of Phosphate (PO)₄ ^3-) Hydrogen Phosphate (HPO)₄ ^2-) And/or dihydrogen phosphate (H)₂PO₄ ^-) And/or

(c) Potassium (K) in the form of potassium salt (K)⁺)。

5. The combination organomineral NPK-Si-humate fertilizer of any of the preceding claims 1 to 3, wherein the humic silicon fertilizer is obtained by incubating an aqueous suspension comprising 45-90 wt.% of a humic acid containing raw material, 5-50 wt.% of amorphous silica and 0.5-10 wt.% of a base to a residual moisture of less than 15 wt.%, based on the total weight of dry components, and then drying.

6. The combined organomineral NPK-Si-humate fertilizer of claim 5, wherein the humic base silicon fertilizer comprises insoluble residues of humic acid-containing feedstock and insoluble residues of amorphous silica.

7. The combo organomineral NPK-Si-humate fertilizer of any of claims 5 to 6, wherein the humic acid containing feedstock is selected from the group consisting of: coal, charcoal, lignite, peat and humus, or mixtures thereof.

8. The combo organomineral NPK-Si-humate fertilizer of any of claims 5 to 7, wherein the amorphous silica is selected from the group consisting of: microsilica, diatomaceous earth, rice hull ash, and zeolite, or mixtures thereof.

9. The combo organomineral NPK-Si-humate fertilizer of any of claims 5 to 8, wherein the base is selected from: alkali metal hydroxides, alkaline earth metal hydroxides, or mixtures thereof.

10. The combined organomineral NPK-Si-humate fertilizer product of any one of the preceding claims, wherein the particulate mineral NPK fertilizer is a fertilizer containing N, P and K; n and P; p and K; and/or a complex fertilizer form of the nutrient compounds of N and K; and/or in the form of a mono-nutrient fertilizer containing compounds of N, P and/or K.

11. The combination organomineral NPK-Si-humate fertilizer product of any one of the preceding claims, wherein the at least one mineral NPK fertilizer is in the form of granules, pellets, extrudates, pellets or agglomerates.

12. The combinatorial organomineral NPK-Si-humate fertilizer product of any one of the preceding claims, wherein the content of nitrogen nutrients in the NPK fertilizer is up to about 46 wt% calculated on elemental nitrogen.

13. The combinatorial organomineral NPK-Si-humate fertilizer product of any of the preceding claims, wherein the content of phosphorus nutrient in the NPK fertilizer is in P₂O₅Up to 55% by weight.

14. The combinatorial organomineral NPK-Si-humate fertilizer product of any of the preceding claims, wherein the content of potassium nutrient in the NPK fertilizer is in K₂At most 62% by weight calculated as O.

15. The combinatorial organomineral NPK-Si-humate fertilizer product of any one of the preceding claims, wherein the NPK-Si fertilizer product further contains other nutrients selected from the group consisting of: calcium (Ca), sulfur (S) and magnesium (Mg), and/or a micronutrient selected from the group consisting of: zinc (Zn), copper (Cu), iron (Fe), boron (B) and molybdenum (Mo).

16. The combination organomineral NPK-Si-humate fertilizer of any one of the preceding claims, wherein the organomineral NPK-Si-humate fertilizer is in the form of a physical mixture or blend of a granular mineral NPK fertilizer and a granular silicon humate fertilizer.

17. The combination organomineral NPK-Si-humate fertilizer of any one of the preceding claims, wherein the organomineral NPK-Si-humate fertilizer is in the form of granules, pellets, extrudates or agglomerates.

18. A method of producing the combo organomineral NPK-Si-humate fertilizer of any one of claims 1 to 17, the method comprising:

-providing at least one particulate NPK mineral fertilizer comprising at least one nitrogen, phosphorus or potassium nutrient compound;

-providing a particulate humic silicon fertilizer obtainable by preparing a suspension comprising 45-90 wt% of a humic acid containing raw material, 5-50 wt% of amorphous silica and 0.5-10 wt% of a base, incubating the aqueous suspension and then drying the incubated suspension until the residual moisture is less than 15 wt%, based on the total weight of the dry components, and

-mixing the at least one granular NPK mineral fertilizer and the granular humus silicon fertilizer.

19. The method of claim 18, wherein the at least one granular mineral NPK fertilizer and granular humic based silicon fertilizer are provided in a ratio such that the ratio of the at least one granular NPK mineral fertilizer to the granular humic based silicon fertilizer is from 10:90 to 90:10 based on the total dry weight of at least one nitrogen, phosphorus or potassium nutrient compound and humic based silicon fertilizer contained in the at least one NPK fertilizer.

20. The method of claim 19, wherein the ratio of the at least one granular mineral NPK fertilizer to the granular humic base silicon fertilizer is from 20:80 to 80:20 based on the total dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and humic base silicon fertilizer contained in the at least one NPK fertilizer.

21. The method of any one of claims 18-20, wherein the humic acid containing material is selected from the group consisting of coal, charcoal, lignite, peat and humus, or mixtures thereof.

22. The method of any one of claims 18-21, wherein the amorphous silica is selected from the group consisting of: microsilica, diatomaceous earth, rice hull ash, and zeolite, or mixtures thereof.

23. The method of any one of claims 18-22, wherein the base is selected from an alkali metal hydroxide, an alkaline earth metal hydroxide, or a mixture thereof.

24. The method according to any of the preceding claims 18-23, wherein the at least one particulate mineral NPK fertilizer contains at least one of the following nutritional compounds:

(a) nitrogen (N) in the form of Nitrate (NO)₃ ^-) Ammonium (NH)₄ ⁺) And/or urea (CO (NH)₂)₂)，

(b) Phosphorus (P) in the form of Phosphate (PO)₄ ^3-) Hydrogen Phosphate (HPO)₄ ^2-) And/or dihydrogen phosphate (H)₂PO₄ ^-) And/or

(c) Potassium (K) in the form of potassium salt (K)⁺)。

25. The method of any one of claims 18-23, wherein the at least one particulate mineral NPK fertilizer and the particulate humic matrix silicon fertilizer are mixed until a homogeneous mixture is obtained.

26. A method of supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, the method comprising applying the combination organomineral NPK-Si-humate fertilizer of any one of claims 1 to 17.

27. A method of supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, the method comprising applying a combination organomineral NPK-Si-humate fertilizer of any one of claims 1 to 15, wherein at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium and a particulate silicon humate fertilizer comprising a chelate of a mono silicic acid-humate compound are applied as separate ingredients.

28. Use of the combination organomineral NPK-Si-humate fertilizer of any one of claims 1-17 for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil.

29. Use of the combination organomineral NPK-Si-humate fertilizer of any one of claims 1 to 15 for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, wherein at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium and a particulate silicon humate fertilizer comprising a chelate of a mono silicic acid-humate compound are applied as separate ingredients.

Technical Field

The present invention relates to NPK-Si fertilizer products and their use in agriculture, environmental protection, detoxification and other fields of use of effective silicon fertilizers. In particular, the present application relates to a combination organomineral NPK-Si-humate fertilizer product comprising a high content of silicon in the form of plant available silicon, and a method of producing such a combination organomineral NPK-Si-humate fertilizer product.

Background

Complex fertilizers such as NPK are widely used to enhance plant growth, however, their widespread use also results in negative environmental effects such as eutrophication, reduction in soil biota and diversity, reduction in soil pH, acceleration of soil organic matter decomposition, increased erosion, and increased accumulation of toxic elements (e.g., heavy metals such as Cd from applied phosphate). Therefore, authorities in many countries have introduced restrictions to reduce the amount of fertilizer.

Nitrogen (N), potassium (K) and phosphorus (P) are macronutrients and are therefore consumed in larger amounts in plants. The main functions of the NPK element in the NPK fertilizer are as follows:

nitrogen (N): nitrogen is vital because it is an important component of chlorophyll, a compound that plants use solar energy to produce sugars from water and carbon dioxide (i.e., photosynthesis). It is also a major component of amino acids (structural units of proteins). Without protein, the plants wither and die. Some proteins act as building blocks in plant cells, while others act as enzymes, which are crucial for many biochemical reactions. Nitrogen is a component in energy transfer compounds such as ATP (adenosine triphosphate). ATP allows cells to conserve and utilize energy released in metabolism. Finally, nitrogen is an important component of nucleic acids such as DNA, which is the genetic material that allows cells (and ultimately whole plants) to grow and multiply. Briefly, nitrogen promotes plant growth.

Phosphorus (P): phosphorus is an important component in plant DNA and RNA. Phosphorus is also important for root, flower, seed, fruit, plant energy development and uptake of other elements including nitrogen.

Potassium (K): potassium is important for strong stem growth, water movement and uptake of other elements including N in plants. Potassium also plays a key physiological role in the carbohydrate and protein metabolism of plants, promoting flowering and fruiting.

Elemental fertilizers such AS Calcium Ammonium Nitrate (CAN), Ammonium Nitrate (AN), Ammonium Sulfate (AS), urea, Single Superphosphate (SSP), Triple Superphosphate (TSP), potash (potassium chloride) (MOP), and combination types such AS monoammonium phosphate (MAP), diammonium phosphate (DAP) are well-defined products prepared using well-defined processes.

Complex or mixed fertilizers such as NPK are more difficult to define because the N/P/K ratio is infinite and the methods used in their production are numerous. The product name "NPK" is usually followed by three numbers to indicate N, P (called P) contained in the product₂O₅) And K (referred to as K)₂O), e.g. 24-6-12, indicates that the particular grade contains 24% N (nitrogen compounds), 6% P₂O₅(phosphorus compound) and 12% of K₂O (potassium compound). In addition, the fertilizer may contain magnesium, boron, sulfur, micronutrients, and the like. Typical content of nutrients (marked as N + P)₂O₅+ K₂O) is usually in the range of 40-60%. Is free of P₂O₅Or without K₂Grades of O are also included in the "NPK" product range, however also commonly referred to as NP and NK fertilizers. The most common NPK fertilizers in europe contain nitrate and/or ammonium salts. Table 1 shows typical average ranges for nutrient content in commercial NPK fertilizers.

NPK FERTILIZERS can be produced in four fundamentally different ways (see "Best Available technologies for polarization preservation and Control in the European Fertilizer Industry, Booklet No. 8 OF 8:" PRODUCTION OF NPK fertilZERS by the MIXED ACID ROUTE "Copyright 2000-EFMA, incorporated herein by reference):

NPK fertilizers based on ammonium phosphate/ammonium nitrate

NPK fertilizers based on nitrated phosphates (mixed acid route)

NPK fertilizers based on nitrated phosphates (ODDA-route)

-mechanical blending of a single nutritional component or a plurality of nutritional components.

TABLE 1 average range of nutrient content in commercial NPK fertilizers (see International Fertilizer Association)

Some with S and/or Mg and/or micronutrients

It should be noted that there are other ways of marking NPK fertilizers, for example, there are criteria for using the elemental value, i.e. the amount of element N, P and/or K.

Plants absorb nutrients primarily in ionic form. Nitrogen is absorbed in the form of ammonium and nitrate salts. Potassium and other metal cation nutrients are absorbed as ions. Phosphorus is absorbed mainly as phosphate (hydrogen phosphate and dihydrogen phosphate). Boron is not absorbed as a charged ion, but as boric acid.

Silicon (Si) has traditionally been considered beneficial. Many cultivated plants absorb more Si than N, P or K (Epstein, E. (2001) "Silicon in plants: acts vs. receptors",Studies in Plant Science,8, 1-15). Active transport of this element by plants was found in 2004 (Ma, J. F. et al (2006) "Ashilicon transport in rice",Nature,440(7084), 688). In recent years, the importance and value of Si as a nutrient in crops has been recognized, particularly the stimulation of the growth of Si-accumulating Plants such as rice and sugarcane, and there are many reports concerning the Role of Si in plant nutrition ("A Review of Silicon in resources and Plants and lines in Role in US Agriculture: History and Future Perspectives", B.S. TUBANA et al,Soil Sciencevolume 181, No. 9/10, 2016). In some countries, Si is now classified as a beneficial element for agriculture (japan, china, usa, south korea).

Thus, it is known that silicon may be a highly beneficial element that enhances plant growth and prevents negative effects on many stresses. Fertilization with silicon protects plants from biotic (disease, insect) and abiotic stress (no)Favourable to climatic conditions, salt, toxicity effects) and to reduce the content of mobile Al and heavy metals in the soil, as well as the total content of Al and heavy metals in cultivated plants (Meharg C, Meharg AA (2015) "Silicon, the silver bulb for presenting biological and biological stress, and improving plant quality, in rice)”Environmental and Experimental Botany, 120:8-17)。

Silicon is the second most abundant element in the earth's crust. However, plants can only absorb Si in the monosilicic acid form or possibly in the form of lower oligomers of monosilicic acid, also denoted herein as bio-available Si or plant-available Si. Solutions of monosilicic acid are thermodynamically unstable but over time, the monosilicic acid polymerizes into polysilicic acid and Si becomes biologically unavailable. In natural silicon-containing minerals, Si exists mainly in a crystalline form or is combined with other elements as silicate minerals having low solubility, and thus is not easily accessible to plants by weathering of the minerals.

The most common and widely used Si fertilizers are slag, i.e. a by-product from steel and pig iron production, and natural minerals such as diatomaceous earth, zeolites, vermiculite, etc. These have the following major disadvantages: 1) they are not very efficient sources of silicon and therefore require large amounts (typically 1-2 tons/hectare/year for slag); 2) slag is also often contaminated with heavy metals, which can be absorbed by plants, thus implying a health risk for the population consuming crops fertilized with such slag. Other known silicon fertilizers include potassium silicate, sodium silicate and calcium silicate. The use of an alkaline medium can increase the solubility of the Si-rich silicate material, however the use of such an alkaline silicate solution has the disadvantage of a high pH, which may be toxic to plants. Thus, high dilution with water (e.g., 1:100) may be required prior to fertilization with an alkaline silicate solution, which adds cost and complexity.

The required high capacity of slag-based and mineral-based Si fertilizers is much higher than that of conventional NPK fertilizers. The existing practice requires two different fertilizing operations at the time of application by the farmer and may require high volumes of Si fertilizer (slag) and separate logistics, which presents practical and economic problems for the farmer. CN 1923766 discloses an NPK compound fertilizer comprising calcium silicate containing slag. However, as mentioned above, fertilization with silicate-containing slag has some disadvantages. RU2223250 discloses a complete complex organomineral fertilizer consisting of an organic fertilizer, a mineral fertilizer NPK and a component containing natural zeolite. The following component proportions are respectively specified: mineral component NPK, organic component peat, diatomite containing natural zeolite = (1.7-1.5): (0.65-0.75): (0.65-0.75). The prepared fertilizer provides all nutrients to the plants, reduces soil acidity, and is used by adding to wells without burning roots and without deteriorating yield quality. In RU2223250, silicon was added as natural zeolite-containing diatomaceous earth, which is a natural mineral, and thus the solubility of silicon was low.

There is a need for an effective silicon fertilizer with Si added in a soluble and plant available form, preferably in the monosilicic acid form. Studies carried out by the present inventors have shown that certain amorphous silicas (silica, SiO)₂) Such as microsilica, may be very useful in this regard. The solubility of Si from amorphous silica is much higher than that of crystalline silica or Si-minerals. This means that the amount of Si fertilizer in kg/hectare can be significantly reduced. This in turn can be used to start with the manufacture of a combination product of Si and NPK fertilizers.

These and other advantages of the present invention will become apparent from the following description.

Summary of The Invention

The present invention combines a more efficient and environmentally friendly silicon fertilizer with an NPK fertilizer in the same product. The invention simplifies the distribution and use of silicon fertilizer and NPK fertilizer for farmers. Thus, the present invention provides a more cost effective and therefore affordable NPK-silicon fertilizer for a wide variety of agricultural products.

In the present invention, the silicon fertilizer used in combination with the mineral NPK fertilizer is a humus silicon fertilizer (hereinafter also referred to as Si-humate fertilizer) having a high content of plant-available Si, which is stable for long-term storage relative to the content of plant-available Si. The Si-humate fertilizers are obtained by reaction between humus and amorphous silica under alkaline incubation conditions, resulting in products with high content of plant available silicon in the form of monosilicic acid-humate complexes. The product can be dried, yet retain high levels of plant available Si, which is also stable for long term storage. The residues of the reaction between humus and amorphous silica do not dissolve during alkaline incubation, providing a long-term positive effect on the soil properties and the production and quality of cultivated plants. By using the Si-humate fertilizer with high content of plant available silicon of the present invention, the amount of silicon fertilizer (expressed in kg/ha; kg/ha) can be significantly reduced compared to conventional silicon fertilizers.

Accordingly, the present invention relates to a combination organomineral NPK-Si-humate fertilizer comprising a particulate mineral NPK fertilizer and a particulate humus-based silicon fertilizer comprising a monosilicic acid-humate complex. It has been demonstrated that the combined use of humic base silicon fertilizers and mineral NPK fertilizers has led to increased potassium and phosphorus uptake by plants. This increased absorption of potassium and phosphorus may result in a decreased ratio of K and P in the NPK formulation, which is an advantage because suitable resources for potassium and phosphorus (potash, apatite and/or other phosphate resources) are drastically reduced in the world. Another advantage of using less phosphorus is less diffusion of heavy metals, which are often a source of contaminating phosphate.

It was also demonstrated that the combination of NPK-Si-humate fertilizers resulted in increased crop yield, indicating increased N uptake. The level of increase in crop yield is up to 30-50% to compensate for the reduced use of NPK while maintaining crop yield. This newly demonstrated result may play an important role in environmental impact, such as less soil degradation (increase of Corg (organic carbon) in soil vials in additional plant root formation; improvement of soil pH since the equilibrium pH of microsilica is 7, whereas traditional NPK fertilizers are 4-5; optimization of soil biota vials, increase of populations of nitrogen-fixing bacteria microorganisms and microtubers (micorrhiza), increase of soil adsorption capacity and decrease of contaminant mobility), less eutrophication (euthrophila) (nutrient leaching) and less nitrogen use, most of which are converted into NOx gases that may lead to global warming. Another advantage identified by the present invention is the reduction in the use of pesticides. It was also observed that the inventive combi-organomineral NPK-Si-humate fertilizer increased the ability of plants to establish water reservoirs in plants, and thus was more resistant to drought periods (abiotic stress). Thus, the combined NPK-Si-humate fertilizer of the invention shows a new impact rate on P and K uptake and has an impact on stimulating biomass growth. Stimulating the plant root system increases the plant's uptake of all elements, including K. An increase in monosilicic acid concentration can convert P that is not available to plants into a form that is available to plants, which also improves P nutrition for cultivated plants.

A first aspect of the invention relates to a combination organomineral NPK-Si-humate fertilizer containing at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium; and a granular humic silicon fertilizer comprising a chelate of a monosilicic acid-humate compound.

In a first embodiment of the invention, the ratio of the at least one granular mineral NPK fertilizer to the granular humic base silicon fertilizer is from 10:90 to 90:10 based on the total dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and the humic base silicon fertilizer contained in the at least one NPK fertilizer.

In a second embodiment of the invention, the mineral NPK fertilizer contains at least one of the following nutritional compounds: (a) nitrogen (N) in the form of Nitrate (NO)₃ ^-) Ammonium (NH)₄ ⁺) And/or urea (CO (NH)₂)₂) (ii) a (b) Phosphorus (P) in the form of Phosphate (PO)₄ ^3-) Hydrogen Phosphate (HPO)₄ ^2-) And/or dihydrogen phosphate (H)₂PO₄ ^-) (ii) a And/or (c) potassium (K) in the form of the potassium salt (K)⁺)。

In a third embodiment of the invention, the humic base silicon fertilizer is obtained by incubating an aqueous suspension comprising 45-90 wt% of a humic acid containing raw material, 5-50 wt% of amorphous silica and 0.5-10 wt% of a base, the amounts being based on the total weight of the dry components, and then drying to a residual moisture of less than 15 wt%.

In a fourth embodiment of the invention, the humic base silicon fertilizer comprises an insoluble residue of a humic acid-containing raw material and an insoluble residue of amorphous silica.

In a sixth embodiment of the invention, the humic acid containing feedstock is selected from: coal, charcoal, lignite, peat and humus, or mixtures thereof.

In a seventh embodiment of the invention, the amorphous silica is selected from: microsilica, diatomaceous earth, rice hull ash, and zeolite, or mixtures thereof.

In an eighth embodiment of the invention, the base is selected from: alkali metal hydroxides, alkaline earth metal hydroxides, or mixtures thereof.

In a ninth embodiment of the invention, the ratio of the at least one granular mineral NPK fertilizer to the humic base silicon fertilizer is from 20:80 to 80:20 based on the total dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and the humic base silicon fertilizer contained in the at least one NPK fertilizer.

In a tenth embodiment of the invention, the at least one particulate mineral NPK fertilizer is a fertilizer comprising N, P and K; n and P; p and K; and/or a complex fertilizer form of the nutrient compounds of N and K; and/or in the form of a mono-nutrient fertilizer containing compounds of N, P and/or K.

In an eleventh embodiment of the invention, the at least one mineral NPK fertilizer is in the form of granules, pellets, extrudates, pellets or agglomerates.

In a twelfth embodiment of the invention, the at least one NPK fertilizer has a nitrogen nutrient content of up to about 46% by weight, calculated as elemental nitrogen.

In a thirteenth embodiment of the invention, the content of phosphorus nutrient in the at least one NPK fertilizer is P₂O₅Up to 55% by weight.

In a fourteenth embodiment of the invention, the content of potassium nutrient in the at least one NPK fertilizer is in K₂At most 62% by weight calculated as O.

In a fifteenth embodiment of the invention, the NPK-Si-humate fertilizer product further comprises additional nutrients selected from the group consisting of: calcium (Ca), sulfur (S) and magnesium (Mg), and/or a micronutrient selected from the group consisting of: zinc (Zn), copper (Cu), iron (Fe), boron (B) and molybdenum (Mo).

In a sixteenth embodiment of the invention, the organomineral NPK-Si-humate fertilizer is in the form of a physical mixture or blend of at least one particulate mineral NPK fertilizer and a particulate silicon humate fertilizer.

In a seventeenth embodiment of the invention, the organomineral NPK-Si-humate fertilizer is in the form of granules, pellets, extrudates or agglomerates.

In a second aspect, the present invention relates to a method of producing a combined organomineral NPK-Si-humate fertilizer according to the first aspect and any one of the first to seventeenth embodiments described above, the method comprising:

-providing at least one particulate NPK mineral fertilizer comprising at least one nitrogen, phosphorus or potassium nutrient compound;

-providing a particulate humic silicon fertilizer obtainable by preparing an aqueous suspension comprising 45-90% by weight of a humic acid containing raw material, 5-50% by weight of amorphous silica and 0.5-10% by weight of a base, incubating said aqueous suspension and then drying said incubated suspension until the residual moisture is less than 15% by weight, and

-mixing the at least one granular NPK mineral fertilizer and the granular humus silicon fertilizer.

In a first embodiment of the method, the at least one granular mineral NPK fertilizer and the granular humic base silicon fertilizer are provided in a ratio such that the ratio of the at least one granular NPK mineral fertilizer to the granular humic base silicon fertilizer is from 10:90 to 90:10 based on the total dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and the humic base silicon fertilizer contained in the at least one NPK fertilizer.

In a second embodiment of the method, the ratio of the at least one granular mineral NPK fertilizer to the granular humic base silicon fertilizer is from 20:80 to 80:20 based on the total dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and the humic base silicon fertilizer contained in the at least one NPK fertilizer.

In a third embodiment of the process, the humic acid containing material is selected from the group consisting of coal, charcoal, lignite, peat and humus, or mixtures thereof.

In a fourth embodiment of the method, the amorphous silica is selected from the group consisting of: microsilica, diatomaceous earth, rice hull ash, and zeolite, or mixtures thereof.

In a fifth embodiment of the method, the base is selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, or mixtures thereof.

In a sixth embodiment of the method, the at least one granular mineral NPK fertilizer contains at least one of the following nutritional compounds:

(a) nitrogen (N) in the form of Nitrate (NO)₃ ^-) Ammonium (NH)₄ ⁺) And/or urea (CO (NH)₂)₂)，

(b) Phosphorus (P) in the form of Phosphate (PO)₄ ^3-) Hydrogen Phosphate (HPO)₄ ^2-) And/or dihydrogen phosphate (H)₂PO₄ ^-) And are and

(c) potassium (K) in the form of potassium salt (K)⁺)。

In a seventh embodiment of the method, the at least one granular mineral NPK fertilizer and the granular humus silicon fertilizer are mixed until a homogeneous mixture is obtained.

In an eighth embodiment of the method, the at least one mineral NPK fertilizer is in the form of granules, pellets, extrudates, pellets or agglomerates.

In a ninth embodiment of the method, the at least one NPK fertilizer has a nitrogen nutrient content of up to about 46% by weight, calculated as elemental nitrogen.

In a tenth embodiment of the method, the phosphorus in the at least one NPK fertilizerThe content of nutrients is expressed as P₂O₅Up to 55% by weight.

In an eleventh embodiment of the method, the at least one NPK fertilizer has a potassium nutrient content in K₂At most 62% by weight calculated as O.

In a twelfth embodiment of the method, the NPK-Si-humate fertilizer product further comprises an additional nutrient selected from the group consisting of: calcium (Ca), sulfur (S) and magnesium (Mg), and/or a micronutrient selected from the group consisting of: zinc (Zn), copper (Cu), iron (Fe), boron (B) and molybdenum (Mo).

In a third aspect, the present invention relates to the use of the combined organomineral NPK-Si-humate fertilizer according to the first aspect and according to the first to seventeenth embodiments of the invention of the first aspect for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil.

In a fourth aspect, the present invention relates to the use of the combination organomineral NPK-Si-humate fertilizer according to the invention for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, wherein at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium and a particulate silicon humate fertilizer comprising a chelate of a mono-silicic acid-humate compound are applied as separate ingredients.

In another aspect, the invention relates to a method for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, said method comprising applying the combination organomineral NPK-Si-humate fertilizer of the invention.

In another aspect, the invention relates to a method of supplying nutrients and/or soil conditioners to agricultural or greenhouse soil, the method comprising applying a combination organomineral NPK-Si-humate fertilizer of the invention, wherein at least one particulate mineral NPK fertilizer comprising at least one nutrient compound of nitrogen, phosphorus or potassium and a particulate silicon humate fertilizer comprising a chelate of a monosilicic acid-humate compound are applied as separate ingredients.

Brief Description of Drawings

FIG. 1: test results showing increased uptake of P in corn roots by application of the combination organomineral fertilizer of the present invention.

FIG. 2: test results showing increased uptake of P in corn shoots by application of the combination organomineral fertilizer of the present invention.

FIG. 3: test results showing increased P uptake in sunflower roots by applying the combination organomineral fertilizer of the present invention.

FIG. 4: test results showing increased uptake of P in sunflower shoots by application of the combination organomineral fertilizer of the present invention.

FIG. 5: test results showing increased uptake of K in corn roots by application of the combination organomineral fertilizer of the present invention.

FIG. 6: test results showing increased absorption of K in corn shoots with application of the combination organomineral fertilizer of the present invention.

FIG. 7: test results showing increased absorption of K in sunflower roots by applying the combo organomineral fertilizer of the present invention.

FIG. 8: test results showing increased absorption of K in sunflower shoots with application of the combination organomineral fertilizer of the present invention.

FIG. 9: test results showing the increase in fresh biomass of corn roots by applying the combination organomineral fertilizer of the present invention.

FIG. 10: test results showing the increase in fresh biomass of corn shoots with the application of the combination organomineral fertilizer of the present invention.

FIG. 11: test results showing the increased fresh biomass of sunflower roots by applying the combo organomineral fertilizer of the present invention.

FIG. 12: shows the results of tests using the combination organomineral fertilizer of the present invention to increase the fresh biomass of sunflower shoots.

Detailed Description

The present invention provides a combination organomineral NPK-Si-humate fertilizer comprising at least one particulate mineral NPK fertilizer and a particulate humic base silicon fertilizer comprising a chelate of a monosilicic acid-humate compound, which alleviates at least some of the disadvantages associated with prior art silicon-containing fertilizers.

In the context of the present invention, the term"plant-available Si" and "bioavailable Si" are understood to mean the silicon compounds which are absorbed or taken up in a transferable form by the roots of plants, i.e. monosilicic acid H₄SiO₄Generally denoted as Si (OH)₄Or possibly a lower oligomer of monosilicic acid.

Without being bound by theory, it is believed that the plant available Si in the Si-humate fertilizers of the present invention is formed by a complexation reaction between monosilicic acid and humic acid derivatives dissolved as humates, thereby forming monosilicic acid-humate chelates that are water-soluble and storage stable. The chelate formed by the complexation reaction prevents the monosilicic acid from polymerizing into polysilicic acid, which is a biologically unavailable form of silicon. The chelate (also called complex) thus formed is also water-soluble, even after drying and long storage.

In the context of the present invention, the term "storage-stable bioavailable Si" is to be understood as meaning that the amount of bioavailable Si in the Si-humate fertilizer fraction remains high even after long storage periods compared to freshly produced products. With respect to the term "long storage", it should be noted that tests carried out by the inventors using Si-humate fertilizers that have been stored for one year surprisingly gave about the same results as freshly produced products, measured as crop yield and silicon uptake.

The Si-humate fertilizer can be prepared as follows:

mixing 45-95 wt% of a humic acid containing raw material, 5-50 wt% of amorphous silica and 0.5-10 wt% of a base (based on the total weight of the dry ingredients) in an aqueous medium to form an aqueous suspension, incubating the suspension at a temperature of 20-70 ℃ for a period of at least 1 hour, and drying the incubated mixture. The residual moisture content of the dried product should be 5-15% by weight.

In the context of the present invention, the term "incubation" may also be interpreted as leaching and/or maturation. Incubation represents a process step in which an aqueous alkaline suspension is left for a period of time at a temperature in which the starting material is leached out in an alkaline solution. Furthermore, the complexation reaction between the dissolved monosilicic acid and humic acid occurs during the incubation.

The humic acid containing material may be any humic substance. The preferred humic acid containing material advantageously has a high content of humic acid. Examples of such humus with a high content of humic acid are different types of coal, such as lignite (brown coal, leonardite), peat and humus. The amount of humic acid containing raw material should be 45-95 wt% based on the total content of the dry material. In one embodiment, the amount of humic acid containing material may be from 60 to 90 wt%, for example from 75 to 85 wt%. The amount of humic acid containing material added to the mixture may depend, for example, on the content of humic acid in the material. The humic acid containing material should be ground to a fine powder with mm sized particles, for example 0.1 to 3 mm, to increase the reaction kinetics.

According to the invention, the amorphous silica suitable for use in the process for producing a humic base silicon fertilizer may be a low cost silica selected from the group consisting of: microsilica, diatomaceous earth, rice hull ash, perlite, zeolite, and calcium silicate minerals, or combinations of these. Amorphous silica is a preferred silica source because amorphous silica has a much higher solubility than crystalline forms of silica already present in soil. Preferred amorphous silicas are microsilica and rice hull ash because of their high specific surface area, which increases the dissolution rate of the silica (provided it can be used in alkaline solutions) to the desired monosilicic acid. The specific surface area of the amorphous silica suitable for use in the present invention should be from about 5 to 50 m²(BET), and particle size in the nanometer or micrometer range, for example 0.01 to 50 μm, preferably less than 5 μm. The morphology and particle size distribution of the amorphous silica should be uniform as this facilitates uniform dissolution of the particles in aqueous alkaline suspension. Microsilica (also known as silica fume) is advantageous because it allows uniform morphology and particle size distribution within a narrow range, as well as a suitably high specific surface area. The term "microsilica" as used in the description and claims of the present application refers to particulate amorphous SiO₂It is obtainable by a process in which silica (quartz) is reduced to SiO-gas and the reduction product is oxidized in the gas phase to form amorphous silica. The microsilica may contain up to70% less by weight of silicon dioxide (SiO)₂) Preferably > 95% by weight of SiO₂And has a specific gravity of 2.1 to 2.3 g/cm³And the specific surface area is 5-50 m²Per g (BET), typically 20 m²(ii) in terms of/g. The primary particles are substantially spherical and may have an average size of about 0.15 μm, calculated as volume. Microsilica is preferably obtained as a by-product in the preparation of silicon alloys in electrical reduction furnaces, but may also be (co-) prepared in other processes. In the following description of the invention, amorphous silicon dioxide is microsilica, however, it should be noted that amorphous silicon dioxide may be of other types as described above.

The amount of amorphous silica added to the mixture for the preparation of Si-humate fertilizers is between 5 and 50 wt%. In one embodiment, the amount of amorphous silica is from 10 to 30 weight percent, such as from 15 to 25 weight percent.

The base should be a strong base, e.g. an alkali metal hydroxide, such as NaOH and KOH, an alkaline earth metal hydroxide, such as Ca (OH)₂Or mixtures thereof. The base may be added to the mixture as a solid material. The alkali neutralizes humic acid in the humic acid-containing feedstock to a water-soluble form of humate. The base also dissolves a significant amount of amorphous silica. The main reaction product is monosilicic acid Si (OH)₄. The amount of base added to the mixture is 0.5-10 wt%. Generally, the amount of base added is less than the stoichiometric amount required to dissolve all of the silica and convert all of the humic acid. However, the amount of base provides sufficient bioavailable Si and humates for germination and initial growth phase. The excess amorphous silica will act as a slow release source to provide adequate fertilization during later growth periods. The initial pH in the suspension should be at least 9.5, and may even be as high as 13, before incubation.

The amount of water in the aqueous suspension should be greater than the (stoichiometric) amount necessary for the reaction, maturation during incubation and chelate formation. The aqueous suspension should preferably have a water content such that the suspension is stirrable and preferably also flowable, in order to be transportable, for example by pumping. Thus, the amount of water may be from 25 to 70 wt.%, based on the total weight of the suspension. However, the dispersion should not contain too much water, as this would increase the energy requirement for removing water in the drying step. Thus, the water content typically does not exceed about 50 wt.%, based on the total weight of the suspension. The water content is preferably from 25 to 40% by weight, based on the total weight of the suspension.

Any suitable mixer may be used to prepare the aqueous suspension, such as a dispersion mixer. Typically, the humic acid containing material and the source of amorphous silica are mixed prior to the addition of the water and base. However, this mixing order is not mandatory, as any mixing order may be used. The mixture thus obtained should be well mixed into a homogeneous suspension, thereby forming an alkaline suspension of dissolved and insoluble components. The suspension is incubated at a temperature and for a period of time wherein the humic acid and amorphous silica partially dissolve under formation of humates and monosilicic acid. Without being bound by theory, it is believed that when monosilicic acid is formed, it chelates through a complexation reaction with the water-soluble humate. Monosilicic acid chemically bound to humate in the form of chelates is prevented from polymerizing to polysilicic acid. Thus, the silicon is bound and remains in a bioavailable form.

The incubation temperature is preferably between 20 and 70 ℃. The incubation time should be 1 hour to several days. The incubation time at normal (i.e., ambient) temperature is typically 2-7 days. An incubation time of 3-5 days at ambient temperature is usually sufficient to carry out the leaching and complexing reactions. During the incubation, the pH of the aqueous suspension will drop from greater than 9.5 or even higher to a neutral pH of about 6.5-7. Experiments have shown that by a combination of elevated temperature and stirring, effects similar to prolonged incubation times at ambient temperature can be obtained. In this case, the incubation time may be reduced to several hours, for example, about 24 hours at 50-60 ℃. Generally, increasing the incubation temperature will decrease the incubation time. Agitation and/or stirring of the suspension during incubation may also facilitate homogenization and dissolution of the monosilicic acid and humic acid and thus reduce the incubation time. An optimal combination of stirring, temperature and base can reduce the incubation time to only about one hour. After incubation, the pH of the suspension is typically about 6.5-7.

The incubated suspension is dried, typically by heating to a product temperature of 15-95 ℃, to obtain a product with a residual moisture content of less than 15 wt.%. The drying step may be carried out outdoors or by using any conventional drying equipment, possibly including heating means, to reduce the water content. When drying outdoors, the drying time depends on the air humidity and temperature. In most cases a residual moisture content of about 10% in the product is suitable, however, it should be noted that the water content may deviate from this specific amount. The product should not be completely dried because such drying may convert the mono-silicic acid chelate to silica, which is a bioavailable form of Si. The dried product may be crushed and sieved, and/or granulated as necessary to produce a product that is easy to handle and use, and suitable for mixing with NPK fertilizers.

In the context of the present invention, the terms "NPK", "NPK fertilizer" and "NPK mineral fertilizer" are to be understood as meaning NPK macronutrient fertilizers generally known in the art. Such NPK fertilizers are typically labeled with NPK analysis based on the relative amounts of the chemical elements N (nitrogen compounds), P (elemental or phosphorus compounds), and K (elemental or potassium compounds), as well as any other nutrients when present. The content of nutrients is traditionally declared as N for nitrogen content; p₂O₅Represents phosphorus, K₂O stands for potassium, but it should be noted that the statement of a nutrient may also be stated as the content of an element, and possibly in other ways. The NPK fertilizer of the invention may comprise three primary nutrients N, P and K; two major nutrients (binary fertilizer, NP, NK, PK); or only one primary nutrient, also known as elemental or mono-nutrient fertilizer, comprising a compound of one of N, P and K. It is to be understood that the N, P and K nutrients are present in the fertilizer as compounds, as is generally known in the art. Thus, the NPK fertilizer of the invention contains at least one of the following nutrients: nitrogen (N) in the form of Nitrate (NO)₃ ^-) Ammonium (NH)₄ ⁺) And/or urea (CO (NH)₂)₂) (ii) a Phosphorus (P) in the form of Hydrogen Phosphate (HPO)₄ ^2-) And/or dihydrogen phosphate (H)₂PO₄ ^-) And/or Phosphate (PO)₄ ^3-) (ii) a And potassium (K) in the form of potassium salt (K)⁺)。

The NPK fertilizer suitable for use in the present invention may further comprise one or more secondary nutrients (Ca, S and Mg) and/or micronutrients (Fe, Mn, Zn, B, Cu, Mo and Cl), as is generally known in the art. Fertilizers can contain fillers and various fillers are available in the fertilizer industry. Fillers are generally inactive, i.e., not nutrients, but can improve soil properties. Fillers generally have the effect of improving the stability of the fertilizer product during storage and handling (e.g. anti-caking agents). The high-quality mineral NPK fertilizer is almost entirely composed of nutrient compounds and only very small amounts of additives, such as anticaking agents and fillers. Thus, elemental NPK fertilizers (e.g., ammonium nitrate) consist essentially of ammonium and nitrate salts, which are forms of nitrogen nutrients absorbed by plants. Accordingly, the NPK fertilizer of element P or K essentially consists of the respective nutritional composition. The same applies to NPK fertilizers containing two main nutrients and to NPK fertilizers containing all three main fertilizers.

In the NPK-Si-humate fertilizer of the invention, wherein the ratio of the at least one particulate mineral NPK fertilizer to the particulate Si-humate fertilizer is from 10:90 to 90:10 based on the dry weight of the product, the relative amount of the NPK fertilizer fraction is based on the sum of the nutrient compounds (i.e. any nitrogen, phosphorus and potassium compounds present in the at least one NPK fertilizer) and the Si-humate fertilizer fraction. Thus, any filler or additive in the NPK fertilizer is not included in the dry weight basis. There are a wide variety of commercial mineral NPK fertilizers with varying amounts of N, P and/or K nutrient content, with or without filler compounds and any other additives.

NPK fertilizers can be produced as a compound fertilizer, wherein the ingredients are mixed prior to forming into granules. Each granule contained N, P and K, ensuring a homogeneous product. NPK fertilizers can also be produced as blended fertilizers, which are physical mixtures of dry NPK fertilizer granules, usually containing different nutrient compounds.

In the mechanical blending process of single or multi-nutrient NPK components, the process requires physical blending of the ingredients in dry form. The ingredients are in the form of individual particles, which may have different bulk densities and particle sizes. To achieve a homogeneous and homogeneous blend, care must be taken to avoid separation and caking of the fertilizer product. According to the invention, the Si-humate fertilizer is one of the dry-mixed components, thereby producing the organomineral NPK-Si-humate fertilizer of the invention.

In the combined organomineral NPK-Si-humate fertilizer of the present invention, the ratio of the mineral NPK fertilizer fraction (i.e. the at least one nitrogen, phosphorus or potassium nutrient compound) to the Si-humate fertilizer fraction should be about 10:90 to 90:10, based on the dry weight of the at least one nitrogen, phosphorus or potassium nutrient compound and the Si-humate fertilizer contained in the organomineral NPK-Si-humate fertilizer product. Throughout the description and claims, the weight ratio of mineral NPK fertilizer to Si-humate fertilizer is based on the sum of at least one nitrogen, phosphorus or potassium nutrient compound in the mineral NPK fertilizer fraction and the dry components of the Si-humate fertilizer fraction contained in the combined NPK-Si-humate fertilizer product of the invention. The organomineral NPK-Si-humate fertilizers can be produced in a wide range, for example the ratio of the mineral NPK fertilizer component to the Si-humate fertilizer can be selected from the following ranges: 20:80 to 80:20, 30:70 to 70:30, 40:60 to 60:40 or 50:50 based on dry weight of the product. It should be noted that the NPK-Si-humate fertilizer of the invention may comprise compounds of all three main nutrients N, P and K; two primary nutrients (NP, NK or PK), or only one of the primary nutrients N, P and K. Generally, the ratio of the fraction of NPK mineral components to the fraction of Si-humate fertilizer should be within the specified range: 10:90 to 90:10, and subranges from 20:80 to 80:20, 30:70 to 70:30, 40:60 to 60:40, or 50: 50.

If the amount of Si-humate fertilizer in the NPK-Si-humate fertilizer is more than about 90% (based on dry weight of the product), the amount of NPK nutrients in the fertilizer will in most cases become too low to meet macronutrient requirements, resulting in reduced crop yield and reduced plant health. In most cases, an amount of Si-humate fertilizer of less than about 10% (based on dry weight of the product) will not meet the silicon nutrient requirements of the plant, and furthermore, the beneficial synergistic effects of the combined NPK-Si-humate fertilizer (e.g. increased phosphorus uptake and increased biomass yield) become less. Tests have shown that a ratio of mineral NPK fertilizer compounds to Si-humate fertilizer of between 30:70 and 70:30 (based on dry weight of the product, as defined above) gives very good results. The combination of the addition of Si-humate fertilizers with traditional NPK mineral fertilizers showed a synergistic effect, in particular in terms of increased phosphorus uptake and increased biomass in plants, compared to the test with NPK fertilizer alone (without Si-humate fertilizer).

The NPK-Si-humate fertilizer is preferably in the form of a blended fertilizer. The blended NPK-Si-humate fertilizer may be a physical (mechanical) mixture of an NPK compound fertilizer and a Si-humate fertilizer. The blended NPK-Si-humate fertilizer may be a physical mixture of one, two or three single primary NPK nutrients and Si-humate fertilizer, or the primary NPK nutrients may be in the form of a mixture of NPK fertilizer containing two primary nutrients (NK, NP or PK) and Si-humate fertilizer. In all of the above cases, the nutrients to be mixed should be in the form of individual dry granules. The Si-humate fertiliser is preferably in the form of agglomerated granules or granules, so as to be compatible with the other ingredients of the blend. The blended NPK-Si-humate fertilizer should have a particle size distribution and bulk density that ensures a quality fertilizer that is not susceptible to any separation of nutrient particles during handling and application.

In all the above embodiments of the NPK-Si-humate fertilizer according to the invention, the product may also contain one or more secondary nutrients (Ca, S and Mg) and/or micronutrients (Fe, Mn, Zn, B, Cu, Mo and Cl).

The NPK-Si-humate fertilizers of the invention are useful for supplying nutrients and/or soil conditioners to agricultural or greenhouse soil. By the inventive method of applying the combined NPK-Si-humate fertilizer of the invention, the farmer's fertilizing operation is simplified due to the distribution of silicon nutrients together with the NPK fertilizer in the combined product. Some of the benefits of the fertilizer according to the invention are a reduced volume of fertilizer to be applied, and a simpler logistics. It should be noted, however, that the combined NPK-Si-humate fertilizer according to the invention may be applied as separate ingredients, i.e. the NPK fertilizer and the Si-humate fertilizer are applied as separate ingredients according to the invention, but are used in combination.

The invention will be illustrated by the following examples. These examples should not be considered as limitations of the present invention, as they are intended to illustrate different embodiments of the present invention and the effects of the use of the invention.

Examples

In the following examples, the mineral NPK fertilizer is denoted "NPK" and the Si-humate fertilizer is denoted "Si AgroA".

Plant analysis of phosphorus (P) and potassium (K) indicates:

three plant samples were collected from each test, washed in distilled water, dried at a temperature of +65 ℃, then ground and passed through a 0.1 mm sieve. Microwave digestion of plant samples was used for total P and K analysis. 0.20 + -0.01 g of plant sample in 4 mL concentrated HNO₃And 2 mL of 30% H₂O₂The mixture was pre-digested overnight and then microwave digested for 30 minutes. K and P were analyzed by ICP-MS I Cap-Q (USA) according to standard methods.

Plant analysis of nitrogen (as nitrate) showed:

analysis of soluble forms of NO in apoplasts and symplast of roots, stems and leaves using the following technique₃。

0.20. + -. 0.01g of fresh plant tissue samples were cut into pieces of about 1-2 cm in length and placed in plastic bottles. Then 50 mL of distilled water was added and the mixture was stirred for 24 hours to allow the apoplast solution to diffuse into the external solution. Filtering the mixture and by using small NO₃Instrument (Twin NO)₃Horiba, japan) analysis of cleaning solutions for NO₃. The filtered plant tissue sample was homogenized to break up all cell walls. The homogenized slurry was mixed with 50 mL of distilled water and stirred for 1 hour. As a result, a diluted coplast solution was obtained and after centrifugation monosilicic acid and soluble forms of NO were analyzed by the method described above₃. Calculating monosilicic acid and soluble form of NO on a dry weight basis based on plant tissue moisture data₃The content of (a).