The invention relates to a surface-treatment composition which is a multifunctional additive comprising the mixture of organic and inorganic components of natural origin. The surface-treatment composition according to the invention, when applied to the surface of solid fertilizers used as plant nutrients, due to its surfactant properties has a positive influence on their properties being equally desirable in terms of handling, storage, distribution and use. On the other hand, compared to the known surface treatment preparations, the surface treatment composition according to the invention is eco-friendly: it enhances the availability of the macro and micro nutrient elements of the treated fertilizer, making thereby possible to save material and energy, i.e. to achieve the same effect by using less composition and thus less energy will be required for the application, which is an important additional benefit.

With a view to the application in plant production as well as to the variations in time and place regarding the manufacture of solid fertilizers, it is extremely important to store them during manufacture, distribution and use without the risk of deterioration in quality. Since one of the main requirements set against solid fertilizers as particulate materials is to prevent pulverization and agglutination to clods which cannot be properly distributed, in most cases strengthening and/or surface treatment additives are used in the fertilizer manufacturing practice. Additives limiting humidity absorption/release play an extremely important role during storage and transport in bulk; however, good moisture capacity and the binding of tiny particles (dust) forming during handling must be ensured. From these demands it is clear that the need exists for a multipurpose surface treatment additive. A well-known example is the incorporation of strengthening additives to granular fertilizers and the surface treatment of fertilizers so as to prevent agglutination and pulverization and to reduce water uptake. In N and PK fertilizers inorganic salts are used as strengthening additives and fatty amines and/or mineral oils or waxes are used for surface treatment. To increase the efficacy of surface treatment, a protective layer may be created on the surface of the particles by the application of inert powders (powdering), such as talk/bentonite/dolomite/diatomite (Gy. Almassy, F. Mate, Gy. Zador: Fertilizers, Technical Editors Budapest, 1977, page 236).

The more recent surface treatment preparations comprise, in lieu of hard-to-treat fatty amines, less toxic anionic/cationic or non-ionic surfactant materials, and, as water repellent component, oils or waxes or the mixture thereof. Strengthening and agglutination inhibiting agents incorporated in fertilizers and/or applied on their surface usually are called in the Anglo-Saxon art as "anti-caking agents". For example, according to the US Patent 6, 110,866, polyglycol ethers or the oxidized products thereof are used as surfactants for liquid or solid core fertilizers, thus they can be also the carriers of herbicide, insecticide, fungicide or other hydrophobic or hydrophilic biologically active materials. These surfactants provide miscibility; however, in order to ensure the appropriate effects, further additives are applied as well. It appears from the description and the examples that a separate anti-caking additive and substances enhancing bioavailability have to be added to the various polyglycol ether derivatives protected in more than 20 claims. Furthermore, some of the polyglycol ethers are long-lived, environmentally harmful substances, while their plant nutrition and growth stimulating effects are unknown.

To eliminate these problems, the Chinese company Shandong Chuangxin Humic Acid

Technology Ltd. offers crystalline, water-soluble humic acid potassium salt (potassium humate) as a strengthening and anti-caking agent for fertilizers. The offered product of natural origin as a fertilizer additive provides the benefits mentioned in connection with the use of polyglycol ethers. Its known favourable biological activity extends from germination through root growth of the plant to the improvement of the quantity and quality of the crop. However, the applicability of this additive is considerably limited due to its alkalinity; the alkalinity of potassium humate dissolved in water can be pH=l l . Upon the effect of minimal moisture, potassium releases ammonia from the nitrate, sulphate and phosphate salts of fertilizers, causing thus a loss of N-fertilizer active agent, generating the pulverization and agglutination of the particles, making the air of the fertilizer store harmful to human health and increasing the risk of fire and explosion. To ensure an appropriate storage time, an additional surface treatment: the use of an oily/waxy additive and/or inert powdering material (dolomite or bentonite powder) is required, such as in the case of the above-referenced US Patent 6,110,866.

The process according to EP2310342A1 comprises mixing a humate mineral suspended in water and having a particle size of from 20 to 400 microns (e.g. leonardite, lignite or humified peat) and a natural surfactant, for example alginic acid and an alkaline component (or alternatively sodium alginate) with solid or liquid fertilizers. This is how an effective fertilizer for plant production or soil remediation is obtained. According to the description, the inventor names the mixture of humic acids and alginic acid with bases as humoalginates. Their nutritive power is obvious; if the alkaline component is potassium (K) and/or ammonium (N) hydroxide, we can call it an N,K macroelement source, too. Furthermore, the known biological effect of a humate in the mixture is enhanced by alginic acid (polymannuronic acid), because saccharic acids are good microbial nutrients themselves. However, the solution according to the description has the disadvantage that the composite preparations prepared by the described process are non-storable: they should be used immediately; consequently, they are not commercial formulations, since the property of the components changes quickly, due to the alkalinity mentioned. Chemical reactions cause deterioration and material loss in the case of both liquid and solid compositions, being thus unsuitable for surface treatment as well. Furthermore, the preparation and dosing of alginic acid makes the production process more complicated, while its material and energy demand makes the process expensive, this is why no information concerning agricultural application has been provided.

According to the Hungarian Patent 175,501, entitled "Composition, based on oil shale, intensifying plant-growth and containing slowly soluble fertilizers", alginate is digested by a base and then it is neutralized by acid treatment, resulting in the increased activity and nutrient-binding capacity of the humic acids precipitated on the surface of the residue of digestion. The agent prepared according to this patent is a moderate humic acid nutrient complex which ensures a permanent and appropriate nutrient level; however, the production process is complicated and material- and energy-intensive: this is why no industrial implementation has taken place. The inventors went on with researching and after five years they managed to obtain another patent protection for the utilization of the multipurpose soil conditioning mineral, alginite. According to the Hungarian Patent 196,446, alginite is being used simultaneously for improving the physical properties, nutrient binding capacity of soils, for increasing water and pH buffer capacity (by the clay and calcite minerals of alginite), for increasing the organic matter and microelement content of the soil (volcanic tuff broils of alginite) as well as for liming, due to the calcium carbonate content thereof. However, so as to achieve the desired effects, it has to be applied as a soil conditioner in a ratio of 10-100 t/ha. Despite its manifold favourable properties, due to the costs of transport and application the sphere of economic use (10 km) is limited to the areas neighbouring the mine. The multipurpose usability as an additive would also be beneficial when mixed with fertilizers; however, the effect of small doses is uncertain, for example due to the extremely diverse organic matter (3-40 %) and calcite (5-50%) contents of alginite as a mineral. To eliminate the disadvantages, according to the Hungarian Patent 200,579, entitled "Process for producing soil improving, nutrient supplying mixture system with controlled effect", alginite is admixed with peat and zeolite, whereby the multifunction effect can be improved; however, doses of several tons of this mixture have to be used, so that the soil improving effect detailed in connection with the Hungarian Patent 196,446 could be safely achieved. In the Hungarian publication document No. HU 1200469 Al soil conditioning preparations comprising alginite and zeolite and having favourable effects on the growing conditions of plants are disclosed; the surface treatment of solid fertilizers, however, is not mentioned there. The US publication document 2003/167811 Al mentions leonardite as the source of humic acid, the purpose of use being, however, to prepare a granular-pelleted fertilizer in admixture with Bacillus bacteria and decontaminated manure. In the international publication document WO 2013/044911 Al, the preparation of compositions promoting plant growth, comprising leonardite and calcite powder, are disclosed, without mentioning the surface treatment of solid fertilizers. In the US publication document US 2005/0395019 Al a granular fertilizer comprising a humate (according to example 1 : leonardite) and a phosphate is described; in the US Patent 3,050,385 oil shale is reacted with fertilizer components for the preparation of slow release fertilizers. None of the publications mentions compositions useful for the surface treatment of solid fertilizers. From the Hungarian Patent 207,504 it is known that the combination of alginite and bentonite can be used as dispersion stabilizator, this combination being used for the surface treatment of solid fertilizers.

Our objective was to provide multifunctional compositions preventing the agglutination and pulverization of solid fertilizers, retarding water uptake and at the same time being suitable for surface treatment with a favourable effect on the availability of nutrients, which compositions equally show favourable effects in measurements made with regard to physical and chemical stability and agricultural efficacy; furthermore, which are eco-friendly products and transmit this property to the solid fertilizers treated by them. Our further objective was to provide compositions which are effective and biologically efficient also in small quantities, so as not to dilute the fertilizer, i.e. to avoid burdening the environment with unnecessary ballast.

During our research work we examined several additives tested already earlier as fertilizer additives, but without any practical results. It has been found that several such below-described components, when used in specific colloidal form, can be surface-active and bioactive even if their alkaline or acid digestion has not been made, since not only the surface coverage, i.e. the efficiency of surface treatment of solid fertilizer products treated by them will increase, if the particle size of the surface treatment composition comprising such additives is reduced to less than 400 microns, preferably less than 40 microns and more preferably less than 10 microns, but the biological efficiency of the solid fertilizers will also be improved. It is presumable that when the particle size is reduced, both hydrophobic and hydrophilic centres are liberated in the additives, which may aggregate again. When comminution is carried out in the presence of positive (+) or negative (-) ions, preferably fertilizer salts and water, the particles of the surface treatment composition do not agglutinate. In this manner a plant nutrient, eco-friendly combination will be obtained, which does not comprise any substances being harmful or only undesired for the environment and at the same time protects the surface of solid fertilizers and makes possible the prolonged storage of the end-products prepared in this way.

It has been discovered that when a mineral containing an organic matter as well as a kerogen, humified portion, preferably leonardite or dudarite, and a clay mineral comprising also organic matter, for example an oil shale, preferably alginite from the localities Gerce (Hungary), Pula (Croatia) or Varpalota (Hungary), is blended into the aqueous solution or suspension of one or more fertilizer components and the particle size is reduced to not more than 400 microns, typically to less than 40 microns and preferably to less than 10 microns, the composition obtained in this manner is suitable for the surface treatment of solid fertilizers, with the simultaneous effect of increasing nutrient availability and plant conditioning.

Based on the above, the invention relates to an eco-friendly composition for the surface treatment of solid fertilizers, to prevent agglutination and pulverization, to retard water uptake and at the same time to increase nutrient availability, having a particle size not more than 400 microns, said composition comprising a mixture consisting of a mineral comprising organic matter and a kerogen, humified portion on the one part and a clay mineral comprising also organic matter on the other part, said mixture having hydrophobic and hydrophilic centres, and one or more known plant nutrients.

The mineral comprising organic matter and a kerogen, humified portion (mineraloid) contains a kerogen, humified organic matter in 70-90 % by weight of its composition. The definition of such minerals can be found in the following reference: Pettit, R. E., 2004: "Organic matter, humus, humate, humic acid, fulvic acid and humin: Their importance in soil fertility and plant health" [http://www.humate.info/main page.html].

The clay mineral comprising also organic matter contains a kerogen, humified portion in 3-40 % by weight and clay in 20-80 % by weight. The definition of such minerals can be found in the following reference: Littke: "Deposition, Diagenesis and Weathering of Organic Matter-Rich Sediments", chapter 6 (Springer Verlag, 2006).

A person skilled in the art will understand that the composition of minerals comprising organic matter and a kerogen, humified portion and that of clay minerals comprising also organic matter is extremely diverse, thus in the surface treatment compositions according to the invention the mixing ratio of for example leonardite used as a mineral comprising organic matter and a kerogen, humified portion (its definition can be found in the following reference: Julia A. Jackson, James P. Mehl, Klaus K. E. Neuendorf 2008, Glossary of Geology, American Geological Institute, 800pp) or dudarite (a mineral having essentially the same composition as leonardite, comprising 60 % by weight of humic acid, mined out in the Hungarian locality Dudar) and alginite used as clay mineral comprising also an organic matter (its definition can be found in the following reference: Macauley, G.; Snowdon, L. R.; Ball, F. D. (1985). "Geochemistry and geological factors governing exploitation of selected Canadian oil shale deposits". 85 (13). Natural Resources Canada: 3. ISBN 978-0-660-11905-2) is optimized to achieve 0.2-60 % by weight, preferably 1-40 % by weight total clay mineral content and 0.2-80 % by weight, preferably 0.5-50 % by weight total humic acid content and a suitable proportion of hydrophilic/hydrophobic centres for surface treatment. The ratio of hydrophilic and hydrophobic centres can be regulated by the ratio of the two components (namely, the clay mineral is more hydrophilic, while the organic matter is more hydrophobic), but the hydrophilic and hydrophobic centres of both components are liberated in the end product obtained by particle size reduction. The number of active centres may increase, in proportion to the size reduction, i.e. to the growth of the surface, to as much as million times the original number: they are to ensure gel stability and the efficacy of surface treatment. The appropriate ratio of the two components can be decided by laboratory tests: when there are many hydrophilic centres, the mixture will feel damp and becomes clotted; when there are many hydrophobic centres, the mixture will exfoliate from the surface of the treated fertilizer.

The eco-friendly surface treatment composition of the invention can be prepared by using, as a fertilizer component comprising positive and negative ions and as plant nutrient, a neutral (pH = 6-8) salt and/or complex compound of macro-, secondary and micro-nutrients (expediently N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu) in the form of an aqueous suspension or solution, or a hydrous salt. These fertilizer components contain free acids (for example nitric acid, sulphuric acid or phosphoric acid with a pH-value between 1 and 5) and free bases (for example ammonium hydroxide, potassium hydroxide or calcium hydroxide with a pH-value between 8 and 14), which are neutralized at the end of the gelation process, if necessary.

The eco-friendly surface treatment composition according to the invention may contain a hydrophylic and/or hydrophobic excipient selected according to the intended use, preferably animal and/or plant oils, fats or waxes; lignin, lignocellulose or vinasse, in 0.1-40 % by weight, preferably 0.2-20 % by weight of the organic matter, and natural clay minerals, for example bentonite in 0-60 % by weight.

Optionally, the Cu and/or S (elementary sulphur) content of the fertilizer components in the eco-friendly surface treatment composition according to the invention can be increased to 0.5-50 % by weight, preferably to 1-40 % by weight, so as to obtain a fungicidal effect in addition to the secondary or micronutrient supplementation.

Optionally, one or more pesticides in 0.1-50 % by weight can also be used in the eco- friendly surface treatment composition according to the invention, in addition to the fertilizer components.

As a supplementation of the fertilizer components, optionally bioactive compounds of natural origin, such as phytohormones (preferably auxin or cytokinin) and/or vitamins can also be used in the eco-friendly surface treatment composition according to the invention.

Without wishing to rely on any theory, in the preparation process of the eco-friendly surface treatment composition according to the invention the mechanical digestion carried out in the presence of the kerogen, humified organic matter results in a gel having hydrophilic and hydrophobic surface-active centres as a multifunctional surface treatment composition, which improves the storing properties of the fertilizer particles, increases its solidity, inhibits pulverization and agglutination; at the same time it can also be used in itself (for example as a foliar and/or seed fertilizer) or even as an additive admixed with known fertilizers, since due to its organic matter, clay mineral and calcite content as well as owing to the humic acids contained it has favourable (poorly soluble, slow-acting) micronutrient complexing/carrying properties. In the mixture of alginite(A)-dudarite(D), with a ratio of AID = 0.1 - 10, preferably 0.2 - 5, the amount of the clay mineral and the humic acid can be adjusted in the ratio desired for surface treatment and the hydrophobic-hydrophylic character can be ensured.

The eco-friendly surface treatment composition according to the invention can be prepared in a known manner. In general, the organic matter comprising also a kerogen, humified portion and the clay mineral as well as the optional further additives are added to the solution or suspension of the plant nutrients intended for use as fertilizer component, or, if the fertilizer is liquid, are suspended in the fertilizer itself in a known manner. The mixture obtained is then subjected to an operation to adjust the particle size of the suspension to not more than 400 microns, preferably to not more than 40 microns and more preferably to less than 10 microns, applying for example a disintegrating slurry pump or a colloidal and/or bead mill. The composition obtained according to the invention can then be used either in itself or in admixture with known fertilizers for the stabilization and surface treatment thereof. The weight ratio of the fertilizer : composition can range between 200 : 1 and 1 : 200.

The use of the new surface treatment composition according to the invention is beneficial not only for the production and storage of solid fertilizers, but also in agriculture, whereby the plants' nutrient uptake and utilization increases, which is reflected in the quantity and quality of the crop, and the same result can be obtained by using less fertilizer. Therefore, the composition according to the invention is eco-friendly compared to the usual well-known fertilizers, since it enhances the vitality, nutrient uptake and stress resistance of living beings. On the other hand, instead of 10-100 t/ha (see: Hungarian Patent No. 196,446 and Dr. Gabor Solti: "Agricultural exploitation of the alginite and oil shale resources of Hungary", MAFI edition. Budapest, 1987) 10-20 kg/ha, in the form of surface treatment, exerts an adequate biological effect.

Main types of the fertilizers useful in the eco-friendly surface treatment compositions according to the invention are: urea (U), ammonium nitrate (AN), dolomitic ammonium nitrate, ammonium sulphate (AS), ammonium thiosulphate, monoammonium phosphate (MAP), diammonium phosphate (DAP), dipotassium phosphate, potassium- monophosphate/phosphate, potassium sulphate, potassium nitrate, potassium chloride, calcium nitrate, calcium magnesium nitrate, mono/dicalcium phosphate, superphosphates, urea phosphate, nitrate, sulphate and chloride salts and organic chelates of micronutrients.

Said types are described in the following references:

1. Gy. Almassy, F. Mate, Gy. Zador: Fertilizers, Miiszaki Kiado (Technical Editors) Budapest, 1977, page 236.

2. Jakab Loch, Arpad Nosticzius: Agrochemistry and plant protection chemistry Bp. 1992. Mezogazda Kiado (Agronomist Editors).

3. Dr. Gabor Solti: "Agricultural exploitation of the alginite and oil shale resources of Hungary", MAFI edition. Budapest, 1987. Other known components that optionally can be used in the eco-friendly surface treatment compositions according to the invention include inter alia the following substances: hydrophilic and/or hydrophobic nutrients, e.g. animal and/or plant oils or fats, waxes, lignin, lignocelluloses or vinasse; known anti-caking agents, dolomite, powders of clay minerals, for example bentonite; pesticides (see for example in the above reference 2); bioactive compounds of natural origin, such as phytohormones (preferably auxin or cytokinin), or vitamins (see for example in the above reference 2).

Water uptake, solidity, pulverization and temperature tolerance measurements have been performed by methods typically used in the fertilizer industry.

Water uptake: volume of water taken up in a Binder KFB 240 climatic chamber

(manufacturer: Binder, Tuttlingen, Germany) at 25 °C, with 80 % relative humidity, in 72 hours, measured on an analytical scale, test portion expressed in %.

Temperature tolerance: due to the multiple recrystallization of ammonium nitrate (above 32.5 °C recrystallization with change of crystal volume, upon cooling recrystallization again) the hardness of the particles decreases: after 20 cycles a considerable decrease can be observed; the static particle hardness is measured using the crumbling force necessary for snapping, in (N) ERWEKA tester device (manufacturer: Erweka, Heusenstamm, Germany).

Measurement of pulverization: 100 g sample is vibrated on EML 200 laboratory vibrating screen for 10 minutes and the fine particle fraction of less than 100 microns is measured with mg accuracy.

Dynamic hardness test: 100 mg granular-pelleted fertilizer is weighed in a self- produced container and by using compressed air 2 bar pressure is set in the container. The air expanding through the lower opening makes the particles hit the wall. The weight of crushed particles is measured and the ratio of the particles which remained intact is calculated in the percent of the weighed portion.

The following examples are included to demonstrate the invention more closely.

Example 1

a) 100 g of leonardite (with particle size less than 1 mm and with 12 % moisture content) were suspended in 300 g of ammonium sulphate solution saturated at 20 °C,

b) then 100 g of alginite from Gerce (with 14 % moisture content and with particle size less than 1 mm) were suspended in 300 g of ammonium sulphate solution saturated at 20

°C,

c) finally, 50 g of leonardite and 50 g of alginite from Gerce (the mixture hereinafter referred to as dual gel) were suspended in 300 g of ammonium sulphate solution saturated at 20 °C.

Suspensions a), b) and c) were separately gelated in a Dyno bead mill (manufacturer: Willy A. Bachofen AG, Switzerland) by milling 90 % to a particle size of less than 40 microns and 50 % to a particle size of less than 50 microns. 7 g of each of gels a), b) and c) were separately sprayed onto the surface of 100 g NPK (10: 15: 15) fertilizer each and then with 2 g of each of the gels the surface of each of 100 g H4N03 + CaMg(C03)2 was treated in a similar manner with 2 g of each of the gels. The water uptake, dynamic hardness, pulverization and temperature tolerance of the samples prepared (the latter being of importance when storing H ₄ NO ₃ + CaMg(C0 ₃ ) ₂ ) were measured and summarized in the following table.

As demonstrated by the measurements, the fertilizers treated with the composition according to the invention, optimized for surface treatment, i.e. with dualgel, have more favourable parameters regarding storage and spreading than the typical (control) surface treatment agents, or alginite alone or leonardite alone (Hungarian equivalent = dudarite). The favourable parameters have been confirmed by the practice, too, i.e. the storage life increased (the degree of caking did not hinder the spreading), and the product of trial manufacture could be spread with the centrifugal spinner broadcasters evenly, without drifting dust. Thus in the further trials the two main constituent mixtures of the composition were used, investigating the effect of various fertilizers and other additives; the results and the biological efficacy are illustrated by further examples.

Example 2

50 g of air-dry (14 % moisture) and ground (below 1 mm particle size) alginite from Gerce (with an organic matter content of 6 % by weight) and 50 g of dudarite (with an organic matter content of 60 % by weight, 14 % moisture) were suspended in 250 g of Nitrosol liquid fertilizer (own produce, U/AN with a mol ratio of 1 : 1, i.e. a mixture of urea/ammonium nitrate solution, density: 1.3 g/cm ³ , N content: 30 % by weight, Zn content: 0.02 % by weight) and then by using a Cavitron slurry pump (manufactured by Warman International Limited, Great-Britain) the average particle size was reduced to less than 40 microns at a maximum temperature of 80 °C. The thixotropic gel produced in this manner was like a tooth paste, containing sufficient surfactant centre, humic acid and clay mineral for the surface treatment of fertilizers with similar consistency.

Example 3

7 kg of the gel prepared according to example 2 was applied onto the surface of 100 kg of NPK (15: 15: 15) fertilizer with a surface treatment rolling drum at a maximum temperature of 80 °C, ensuring thereby adequate mixing and drying. The product prepared in this manner can be spread without pulverization with centrifugal spinner broadcasters as well. The dynamic hardness of the gel -treated fertilizer increases from 61.1 % to 74.1 % and the fertilizer does not cake even after one year of storage. The water uptake is 6-7 %, which corresponds to that of the product prepared by the surface treatment performed with the Galoril surface treatment substance (product of the US firm ArrMaz). Based on agricultural small pot tests (see for example in the above reference 4), the NPK fertilizer treated according to this example increased the amount of green mass in the initial phase of growth by 10-20 % and in large plot trials it increased the amount of crop by 5-10 % in the case of maize and wheat, compared to the control (the same NPK without surface treatment).

Example 4

Based on example 2, a gel was prepared from 50 g of air-dry and ground (less than 1 mm of particle size) alginite from Gerce (with an organic matter content of 6 % by weight) and 50 g of dudarite (with an organic matter content of 60 % by weight) in 220 g of ammonium sulphate (AS) solution saturated at ambient temperature. 2 g of the gel was sprayed onto 100 g of granulated (without Galoril surface treatment substance) particles of NH4N03 + CaMg(C03)2 stirred in a rolling drum. The fertilizer, the surface of which was treated in this manner, was dried at ambient temperature for one day, spread in a thin layer in the laboratory. The dynamic hardness and water uptake of the product, based on measurements standardized at 107 °C, were identical with the parameters of the typical product, the surface of which was treated with Galoril, and its temperature tolerance increased by 10 %, thus it would not pulverize even when provisionally stored in the open air (the measurement results can be seen in the last row of the table of example 1).

Example 5

Air-dry dust of 6.6 g of dudarite and 13.4 g of alginite from Pula was suspended in 80 g of a solution of ammonium sulphate (AS) and urea (U), mol ratio AS/U = 1 :4, water content: 30 %, followed by the preparation of a gel by the aid of a Dyno bead mill at a maximum temperature of 80 %, reducing thereby the average particle size below 10 microns. The gel was used for surface treatment according to example 4. The water uptake (amount of water taken at 25 °C, with 80 % relative humidity, in 72 hours) decreased to 5-6 %, which is better (less) than the water uptake of the sample of example 2, because U+AS are less water- absorbing than U+AN (Nitrosol). Particle hardness increased by 10% and water uptake decreased, compared to example 3. Agricultural measurements (see for example the above reference 4) of identical NPK doses showed 10-20 % surplus compared to the usual harvest in the case of wheat and rape as well.

Example 6

Suspension was prepared by adding 8 g of dudarite and 8 g of alginite from Pula to 80 g of the AS+U solution of example 5, followed by gelation by the aid of a Dyno bead mill, while adding 16 g of sulphur dust. The thus obtained composition can be used for the surface treatment of NPK, and a secondary nutrient, i.e. sulphur (S) substitute can also be used as a suspension-type foliar fertilizer either with the NPK fertilizer or alone. Further, the agricultural activity shown in the previous examples is completed with plant protecting activity, since the powdery mildew killing ability of colloidal sulphur is well-known (see for example the above reference 2).

Example 7

To a (1 : 1 mol ratio) solution of 80 g of calcium magnesium nitrate in 50 % by weight of water the air-dry powder of 6.6 g of dudarite and 13.4 g of alginite from Pula and 60 g of urea are added and then the resulting suspension is gelated in Frymakoruma colloidal mill (manufacturer: Frymakoruma AG, Rheinfelden, Germany). The resulting surface treatment composition is sprayed onto the surface of a fertilizer of 7:28: 14 NPK ratio, obtaining thus a starter fertilizer with good storage and usability properties (agricultural efficacy was confirmed by a germ test according to MSZ 22902/4-76 standard).

Example 8

To the gel prepared according to example 7, 20 g of fruit tree oil or even edible oil, 20 g of sulphur powder and 32 g of blue vitriol + 3 g of zinc sulphate monohydrate and finally 6 g of calcium oxide are added during vigorous stirring. The suspo-emulsion homogenized by stirring was reground in a Dyno bead mill (below 10 microns in 90 %) and then gelated. By diluting the gel with 5-10-fold amount of water it is used for winter wash-down spraying. Besides its fungicidal (S, Cu) property it has surface spreading ability, which makes it an insecticide and ovicide and it heals pruning wounds.

Example 9

20 g of air-dry, ground (less than 1 mm particle size) alginite (with 6 % organic matter content) and 20 g of dudarite (with 60 % organic matter content) are mixed during grinding with 6 g of boric acid, 5 g of iron sulphate pentahydrate, 6 g of manganic sulphate, 2 g of zinc sulphate monohydrate, 14 g of ammonium sulphate and 27 g of urea in a disintegrator (for example in a size reduction and dispersion equipment with rotating hammers (manufacturer: the firm Hosokawa Micron, Osaka, Japan) and then the mixture is finely ground in an air-jet mill, in gas flow at a pressure of 2 bar and at a temperature of 40 °C. The fine fraction of less than 40 microns is separated from the gas flow and an aliquot of 5 g is mixed with 95 g of NPK fertilizer, followed by the preparation of premium quality fertilizer by pressing or by particle forming in a drum granulator, which fertilizer contains, in addition to the primary nutrients, micro-nutrients as well and its quality is better than it is usual, even without surface treatment.