WO2015091605A2

WO2015091605A2 - Method of use of a composition comprising hydrogen sulphide donor and seed composition comprising hydrogen sulphide donor

Info

Publication number: WO2015091605A2
Application number: PCT/EP2014/078151
Authority: WO
Inventors: Rasik H. Raythatha
Original assignee: Solvay Sa
Priority date: 2013-12-19
Filing date: 2014-12-17
Publication date: 2015-06-25
Also published as: WO2015091605A3

Abstract

Method of use of a composition comprising hydrogen sulphide donor and seed composition comprising hydrogen sulphide donor A method of use of hydrogen sulphide for enhancing melioration of soil, plant growth, seed germination and/or photosynthesis, wherein the hydrogen sulphide is provided in the form of a hydrogen sulphide donor.

Description

METHOD OF USE OF A COMPOSITION COMPRISING HYDROGEN SULPHIDE DONOR AND SEED COMPOSITION COMPRISING HYDROGEN SULPHIDE DONOR

This application claims priority from U.S. provisional application No.61/918016 and U.S. provisional application No. 61/918019, the whole content of these applications being incorporated herein by reference for all purposes.

The present invention concerns a method of use of hydrogen sulphide for enhancing plant growth, seed germination and/ or photosynthesis, and suitable compositions, and preferably, the present invention concerns, in a first section, a method of use of a composition comprising at least one hydrogen sulphide donor, wherein the composition is applied to the soil, a respective soil meliorating composition, and a process for its manufacture; and in a second section, a seed composition comprising seeds and at least one hydrogen sulphide donor, a process for the manufacture of such a composition, and a method of use of such a composition.

Gaseous H2S (hydrogen sulphide) and H2S dissolved in water is known to exhibit beneficial biological effects on seeds and plants, as described e.g.

in F.D. Dooley et al, PLOS One, 2013, Vol. 8(4), e62048. A positive effect is also registered when seeds are treated in an aqueous solution of metal sulphide or metal hydrogen sulphide, as described in CN103141511.

Object of the present invention is to provide improved methods of providing hydrogen sulphide in agricultural applications, especially to meliorate soils and to enhance plant growth, seed germination and/or photosynthesis of plants. Another object of the present invention is to provide compositions with improved properties, especially in view of meliorating soils and enhancing plant growth, seed germination and/or photosynthesis of plants, but also in view of a better handling of such compositions. These and other objects of the invention are achieved by the invention as outlined in the description and the claims.

It was found that the application of a hydrogen sulphide donor to the soil and/or the presence of a hydrogen sulphidesulphide donor in a seed composition benefits plant growth, germination and/or photosynthesis. Preferably, the hydrogen sulphidesulphide donor is solid. Accordingly, the invention concerns a method of use of hydrogen sulphide for melioration of soil, enhancing plant growth, seed germination and/or photosynthesis, wherein the hydrogen sulphide is provided in the form of a hydrogen sulphide donor. The advantage of applying a hydrogen sulphide donor, especially a hydrogen sulphide donor in solid form, instead of, for example, a solution of hydrogen sulphide or a dissolved sulphide salt, or of gaseous hydrogen sulphide, is that the release of hydrogen sulphide is temporally extended, application and sulphide release control of the composition is improved.

Preferably, at least 50% by weight of the hydrogen sulphide donor are in solid form. More preferably, the hydrogen sulphide donor preferably is in solid form.

The term "soil" in the frame of the present application denotes soil which is carrying plants. A listing of preferred plants is given below. The term "soil" also denotes soil which is intended to be used for the plantation of seeds of any plants. A listing of any seeds which can be planted on soil is given below. The term "soil" is also intended to include the soil of fields and soil sold in packages or bulk form to be distributed on suitable areas.

A preferred method of use, wherein the at least one hydrogen sulphide donor preferably is a solid, relates to embodiments wherein

a) The at least one hydrogen sulphide donor is comprised in a

composition which is applied to the soil, or

b) The at least one hydrogen sulphide donor is comprised in a seed

composition which comprises seeds.

Another aspect of the present invention relates to a composition

comprising at least one hydrogen sulphide donor and at least one additional agent selected from the group consisting of seeds, a formulating agent, at least one additional agriculturally active agent and at least one auxiliary agent. Once again, in such compositions, the temporal release of hydrogen sulphide is extended. The compositions, especially if containing the hydrogen sulphide donor in solid form, are easier to handle compared to gaseous hydrogen sulphide or an aqueous solution.

The two preferred embodiments - a composition suitable to be applied to soil and its application to the soil, and a seed composition and the use of which - are explained now in further detail. Seed compositions comprising seeds and at least one hydrogen sulphide donor and the use of such seed compositions are described in the following paragraphs denoted as "first section".

The present invention concerns, in a first section, a composition comprising seeds and at least one hydrogen sulphide donor. This composition is also denoted as "seed composition". The composition provides a release, preferably controlled release, of a suitable amount of gaseous H2S and/or dissolved H2S and/or an aqueous solution containing S ^" when the seed composition is brought into the soil and/or after sowing. Often, the release of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" is supported by contact with environmental water or controlled irrigation. The presence of a suitable amount of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" at various stages of the germination of the seed and early growth of the seedling improves germination speed, quality and resistance of the seedling to adverse conditions, such as adverse climate conditions, use of herbicides or other chemicals on the crop, exposure to pathogens or pests, salinity or osmotic stress. Plant growth stages requiring photosynthesis also benefit from controlled release of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" from the composition. The composition allows for controlled application of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" at various stages of germination and seedling growth,

circumventing issues of handling of toxic gaseous H2S or toxic, often fast decomposing solutions of H2S donors, dosage problems or the need for multiply repeated treatment of the seeds or seedlings after sowing or planting.

The first section of the invention therefore concerns a seed composition comprising seeds and at least one hydrogen sulphide donor. In one embodiment of the invention, the seed composition further comprises a formulating agent. The invention further concerns a process for the manufacture of such seed compositions and a method for its use. The seed composition may be present in the form of seeds coated with at least one additional ingredient, especially, coated with the at least one hydrogen sulphide donor and/ or the optional formulating agent, and/or at least one auxiliary agent. Such agents are described below in detail.

The term "seeds" as used especially in the first section of the present invention is intended to denote any seeds that are suitable for the production of plants, preferably for human or animal consumption, or for further manufacture of industrially applicable products such as fibers, textiles, fuels or polymers. Generally, the invention is not limited to specific species of plant seeds. The species include fruits such as pear-like fruits, stone fruits, and soft fruits (apple, pear, plum, peach, Japanese apricot, prune, almond, cherry, strawberry, raspberry, black berry, tomato, pepper), cereals, roots, legumes, tubers such as beets and potatoes, herbs, spices, camphor trees (avocado, cinnamon, camphor, etc.), ornamental plants, fiber plants such as flax or cotton, drug plants and oil producing plants, for example rape, canola, mustard, poppy, olive, sunflower, coconut, castor, cocoa bean, peanut and soybean; tobacco, nuts, coffee, sugar cane, tea, grapevine, hop and banana. More preferably, the species include cereals. Even more preferably, the seeds include rice seeds, wheat seeds, rye seeds, maize seeds, quinoa seeds, oats seeds, barley seeds, millet seeds, sorghum seeds, teff seeds, triticale seeds, spelt seeds and buckwheat seeds. The most preferred cereal species are rice and maize. Other preferred plants include potato, carrot, sweet potato, sugar beet, bean, pea, chicory, lettuce, cabbage, cauliflower, broccoli, turnip, radish, spinach, asparagus, onion, garlic, eggplant, pepper, celery, squash, pumpkin, zucchini, cucumber, apple, pear, quince, melon, plum, cherry, peach, nectarine, apricot, strawberry, grape, raspberry, blackberry, pineapple, avocado, papaya, mango, banana, soybean, tomato and raspberries.

The seed composition according to the first section of the present invention may comprise more than one seed species, for example, two or more.

The term "hydrogen sulphide donor" as used in all sections of the present invention is intended to denote a chemical compound which is able, under agricultural conditions, to release H2S, or releases dissolved H2S and/or aqueous solution containing S ^". Of course, two or more compounds can be applied simultaneously as hydrogen sulphide donor. The released H2S and/or dissolved H2S and/or aqueous solution containing S ^" may be available to the seed and/or seedling and/or plant as gas, dissolution or solution in a suitable concentration as to provide a beneficial biological effect, such as improved germination rate, growth rate and/ or photosynthesis. Suitable hydrogen sulphide donors may be either organic or inorganic. Inorganic hydrogen sulphide donors are preferred. More specifically, metal sulphide and/or metal hydrogen sulphides are preferred. Preferred metal sulphide and/or metal hydrogen sulphides are selected from the group consisting of CaS, KHS, NaHS, Na₂S, MgS, SrS, BaS, SiS. Most preferred inorganic hydrogen sulphide donors are CaS, SrS and BaS. CaS is more particularly preferred. In one embodiment of the first section of the invention, the seeds may be pre-treated prior to being added to the seed composition, e.g. thermal treatment, treatment with antifungal agents such as captan, treatment with insecticides, growth enhancers, fungi etc.

In a particular embodiment of the method of use according to the first section of the invention, the water content of the seed composition is low.

Generally, the water content is equal to or less 10000 ppm. Preferably, the water content is equal to or less than 8000 ppm. Most preferably, the water content is equal to or less than 5000 ppm. Generally, the water content is equal to or higher than 0 ppm. In some cases, a water content of equal to or higher than 500 ppm is preferred. The water content may also be equal to or higher than 1000 ppm. Often, water content may also be equal to or higher than 3000 ppm. If the process allows, a water content of even less than 100 ppm is achieved; often, the water content is then equal to or higher than 5 ppm. In a most preferred embodiment, the water content is from 100 ppm to 10000 ppm. The water content, expressed as "ppm" is ppm="parts per million" of weight in relation to the weight of the seed composition, wherein the composition comprises all ingredients such as seeds, the at least one hydrogen sulphide donor, optionally the at least one formulation, and other optional ingredients such as agriculturally active agents and/or auxiliary agents.

The amount of the at least hydrogen sulphide donor in the seed

composition according to the first section of the invention is described as S ^"- content in wt %. The S ^"-content, expressed as "wt %" (wt ="weight percent"), is wt % of weight in relation to the weight of the seed composition, wherein the composition comprises all ingredients such as seeds, the at least one hydrogen sulphide donor, optionally the at least one formulation, and other optional ingredients such as agriculturally active agents. It should be understood that, in the case of an inorganic hydrogen sulphide donor, the term S -content denotes the S -content which is comprised in an inorganic hydrogen sulphide donor, for example in CaS. Further, it should be understood that, in the case of an organic hydrogen sulphide donor, the term S -content denotes the theoretical stoichiometric amount of H2S which can be released by the organic hydrogen sulphide donor, e.g. by contact with water, aqueous solutions and/or acids.

Generally, the S -content of the seed composition is equal to or less

than 10 wt %. Preferably, the S ^"-content is equal to or less than 8 wt %. Most preferably, the S 2-^"-content is equal to or less than 5 wt %. Generally, the S 2-^"- content is equal to or higher than 1 wt %. Preferably, the S -content is equal to or higher than 2 wt %. Most preferably, the S -content is equal to or higher than 3 wt %.

According to the first section of the invention, the at least one hydrogen sulphide donor preferably is a solid. In another embodiment, the at least one hydrogen sulphide donor is a liquid. The at least one liquid hydrogen sulphide donor may suitably be applied to the seed composition in combination with a formulating agent, such as a solid carrier.

In one embodiment of the first section of the invention, the seed

composition further comprises at least one formulating agent. The at least one formulating agent is selected from the group consisting of a binder, a polymer, a cellulose derivative, a surfactant, a fat or an oil, an organic salt or an inorganic salt. The at least one formulating agent is agriculturally compatible. Preferably, the at least one formulating agent is selected from the group consisting of polysaccharides, polysaccharide derivatives, super- absorbent polymers, water- insoluble polymers, water-soluble polymers and biodegradable polymers, gypsum, phosphor salts, clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers, surfactants (surface-active agents), which may be an

emulsifying, dispersing or wetting agent of the ionic or nonionic type; fillers and plastisizers, or polyelectrolyte complexes. More preferably, the at least one formulating agent is selected from the group consisting of polyesters, polyether esters, polyanhydrides, polyester urethanes, polyester amides; polyvinyl acetates; polyvinyl acetate copolymers; guar derivatives (e.g. guar galactomannan);

polyvinyl alcohols and tylose; polyvinyl alcohol copolymers;

polyvinylpyrrolidones; sugars, in particular polysaccharides, including starches, modified starches and starch derivatives, dextran, maltodextrins, dextrin, alginates, chitosanes and celluloses, cellulose esters, cellulose ethers and cellulose ether esters including ethylcelluloses, methylcelluloses,

hydroxymethylcelluloses, hydroxypropylcelluloses and carboxymethylcellulose; fats; oils; proteins, including casein and caseinate salts, gelatin and zeins; gum arables; shellacs; vinylidene chloride and vinylidene chloride copolymers;

lignosulfonates, in particular calcium lignosulfonates; polyacrylates,

polymethacrylates and acrylic copolymers; polyvinylacrylates; polyethylene oxide; polybutenes, polyisobutenes, polyethylene glycol, polystyrene,

polyethyleneamines, polyethylenamides; acrylamide polymers and copolymers; polyhydroxyethyl acrylate, methylacrylamide monomers; polychloroprene; latex; styrene-acrylate based copolymers; wood flours, wood pulp, paper pulp, peat, cereal flours, tree bark mill, wood meal and nut shell meal, activated carbon, fine-grain inorganic solids, silica gels, silicates, clays, vermiculite, chalk, diatomaceous earth, calcium carbonate, magnesium carbonate, dolomite, magnesium oxide, potassium phosphate, titanium dioxide, mica, calcium sulfate and the like; clays and inorganic solids such as calcium bentonite, kaolin, china clay, talc, perlite, mica, vermiculite, silicates, quartz powder, montmorillonite, attapulgite, bole, loess, limestone, lime and mixtures thereof; cereal flours, which includes wheat flour, oat flour and barley flour. Most preferred formulating agents are cellulose derivatives, such as methyl cellulose. In another preferred embodiment, the at least one formulating agent is selected from the group consisting of colours, dyes and colorants. Specific colours, dyes and colorants are for example, Chromatint^® dyes. There is no limitation to the colours of the colours, dyes and colorants; preferred colours are red, yellow and green.

In another embodiment of the first section of the invention, at least one pH regulating formulating agent is comprised in the seed formulation, such as lime. This can serve to aid to control H2S release, e.g. in acid soils.

In a further embodiment of the first section of the invention, the seed composition further comprises at least one additional agriculturally active agent. As used herein, the term "agricultural active agent" denotes any chemical element, molecule, or compound, or mixture thereof, which has properties which enhance the efficiency of the agricultural activity. For example, agricultural active agent can enhance or control a biological activity in a seed, a plant, or a disease or pest of a seed or plant; or function as antidote against herbicides. Such agricultural active agents include, but are not limited to, pesticides, herbicides, fertilizers including nutrients (macronutrients and/or micronutrients), such as ammonium sulfate, ammonium phosphate, herbicide antidotes such as oximes, ammonium nitrate, ureas and mixtures thereof, plant growth regulators, drugs, dyes, biological attractants, scents and pheromones.

In a further embodiment of the first section of the invention, the seed composition further comprises at least one auxiliary agent. The term "auxiliary agent" is intended to denote in particular an agent fostering the applicability selected from the group consisting of water, oil of plant, animal or synthetic nature, organic solvents or aqueous solutions. An auxiliary agent may be advantageously present in the formulation process of the composition, e.g. to avoid dusting or enhance adhesion. In certain aspects, the optional auxiliary agent can also be fully or partly removed during the process according to the invention for manufacturing the composition containing the hydrogen sulphide donor.

In a preferred aspect of the first section of the invention, the seed composition is solid.

In one aspect of the first section of the present invention, the composition according to the present invention has a specific H₂S release-rate. Generally, the H₂S release-rate of the claimed composition is equal to or less than 100 ppm/day, wherein one day denotes 24 hours. Preferably, the H₂S release-rate is equal to or less than 10 ppm/day. Most preferably, the H₂S release-rate is equal to or less than 1 ppm/day. Generally, the H₂S release-rate is equal to or higher

than 0.001 ppm/day. Preferably, the H₂S release-rate is equal to or higher than 0.005 ppm/day. Most preferably, the H₂S release-rate is equal to or higher than 0.01 ppm/day.

In the first section of the present invention, the H₂S release-rate is determined by suitable detection methods such as "UOP9-85 Hydrogen Sulphide in Gases by the Tutwiler Method"; UOP Method 212, "Hydrogen Sulphide, Mercaptan Sulfur and Carbonyl Sulphide in Hydrocarbon Gases by

Potentiometric Titration", H2S probes which are commercially available, such as GA24XT-H, precipitation or gravimetric methods (e.g. copper ion solution titration), methylene blue method; or H2S adsorption in Cd- or Zn-acetate solution with subsequent iodometric analysis. Preferably, the H2S release rate is measured by H2S probe or precipitation of copper sulphide with gravimetrical analysis.

In the first section of the present invention, the invention also concerns a process for the manufacture of the seed composition comprising the seeds and the at least one hydrogen sulphide donor. In one aspect of this first section of the invention, the process for manufacturing the composition comprising the seeds and the at least one hydrogen sulphide donor according to the invention comprises mixing the seeds and the at least one hydrogen sulphide donor.

Optionally, at least one formulating agent as set forth above, and/or at least one additional agriculturally active agent are present in the process. In the mixing process, the ingredients can be added either in combination or consecutively. Optionally, at least one auxiliary agent, preferably chosen from the group consisting of water, oil of plant, animal or synthetic nature, organic solvents or aqueous solutions is added at any time during the mixing process. If any one of the ingredients selected from the at least one hydrogen sulphide donor and the at least one formulating agent which is optionally present and/or at least one agriculturally active agent is a liquid, the mixing process is also referred to as "wet mixing". If all of the ingredients selected from the at least one hydrogen sulphide donor and the at least one formulating agent which is optionally present and/or at least one agriculturally active agent is solid, the mixing process is also referred to as "dry mixing". Dry mixing may include also dusting and milling. If desired, the process also comprises the step of applying heat and/or reduced pressure during mixing and/or after mixing is completed. Applying heat and/or reduced pressure during mixing and/or after mixing is completed is especially preferential in the case when the auxiliary agent is or contains water. The process may also optionally include at least one drying step, wherein the at least one drying method is preferably selected from the group consisting of heating, hot air, reduced pressure, IR drying, freeze drying, drying at ambient conditions (e.g. on the air at ambient pressure and temperature). The process may also include optionally at least one cooling step. The mixing can be carried out in any equipment suitable for such mixing, such as tumbling mixers, shear mixers employing rotating shapes, drum mixers, Z-blades, ribbon blades, orbiting screws, pan mixers, Muller mixers, Auger mixers, spinning disk distribution mixers, impellers, air lift mixers, fluidized bed mixers, rotor-stator mixers, hopper discharge blenders and stockpile blenders, free fall mixer (tumble mixer, stagger mixers, mixing pear, comical-, dual conical-, V-mixer, tetrahedral mixer). Most preferably, the equipment is chosen such that no or essentially no segregation of the seeds, the at least one hydrogen sulphide donor and other optionally present ingredients occurs, resulting in a homogenous or essentially homogenous blend, minimizing damage to seeds.

In another embodiment of the first section of the present invention, , the process for manufacturing the seed composition comprising the seeds and the at least one hydrogen sulphide donor according to the invention comprises coating the seeds at least partially with the at least one hydrogen sulphide donor. In the present aspect of the invention, the seeds may be coated with at least one layer comprising the at least one hydrogen sulphide donor. Optionally, at least one formulating agent as set forth above, and/or at least one additional agriculturally active agent are comprised in the one or more layers which coat the seeds.

Optionally, at least one auxiliary agent, preferably chosen from the group consisting of water, oil of plant, animal or synthetic nature, organic solvents or aqueous solutions is added at any time during the manufacturing process. In one aspect of the process according to the present invention, the seeds are coated with more than one layer. At least one of those layers comprises at least one or more hydrogen sulphide donor, and optionally at least one or more formulating agent and/or additional agriculturally active agent and/or auxiliary agent. Other layers may comprise at least one or more formulating agent and/or additional agriculturally active agent and/or auxiliary agent, and no H2S donor. In a preferred embodiment, the one or more layers on the seeds are applied such that the rate of H2S release and/or formation of dissolved H2S and/or formation of a S -containing aqueous solution is controlled.

In one preferred embodiment of the first section of the present invention, the process of manufacturing the seed composition comprising seeds and at least one H2S donor, wherein the seeds coated with at least one layer comprises at least one step selected from the group of preparing a solution or dispersion or slurry of the at least one hydrogen sulphide donor and/or the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent. To prepare the solution or dispersion or slurry, solvents are chosen which are agriculturally acceptable, which will vary with the seeds which are coated. Suitable solvents include water, organic solvents, aqueous solutions, molten polymers and mixtures of any of the foregoing. In a further step, the solution or dispersion or slurry is applied to the seeds or the coated seeds. The application technique is selected from the group of dipping, spraying, misting, mixing, soaking and immersing. In one aspect of the invention, the treated seeds are separated in a next step from the solution or dispersion or slurry by filtration. This step is often followed by a drying step, in which the treated seeds are subjected to at least one drying step selected from the group consisting of heat, hot air, blowing, reduced pressure, IR drying, freeze drying and drying under ambient conditions (e.g. on the air at ambient pressure and temperature). After removal of the solvent, a coating comprising one or more layers has formed on the seeds, wherein the coating comprises the at least one hydrogen sulphide donor and/or the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent. The process may also include optionally at least one cooling step.

In another aspect of the first section of the invention, after applying the solution or dispersion or slurry to the seeds, the solvent is removed completely or essentially completely from the seed/solution(dispersion/slurry) mixture by at least one technique selected from the group consisting of heating, hot air, reduced pressure, IR drying, freeze drying, drying at ambient conditions (e.g. on the air at ambient pressure and temperature) such that all or essentially all of the at least one hydrogen sulphide donor and/or the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent forms a coating on the seeds. The coating may comprise one or more layers.

In another aspect of the first section of the invention, after applying the solution or dispersion or slurry, the solvent is removed partially from the seed/solution(dispersion/slurry) mixture by at least one technique selected from the group of heating, hot air, reduced pressure, IR drying, freeze drying, drying under ambient conditions (e.g. on the air at ambient pressure and temperature) such that part or all or essentially all of the at least one hydrogen sulphide donor and/or the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent forms a coating on the seeds, e.g. by precipitation, co-precipitation or another adherence

mechanism. Any excess of solvent, solution and/or dispersion and/or slurry may be removed after this step by filtration, spinning or other suitable separation method. Preferably, the removal of the solvent, solution, slurry and/or dispersion is followed by at least one drying step, selected from the group consisting of heating, hot air, reduced pressure, IR drying, freeze drying, drying under ambient conditions (e.g. on the air at ambient pressure and temperature). The process may also optionally include at least one cooling step.

In a preferred aspect of the first section of the invention, the one or more layers of coating are applied to the seed by wet mixing and/or dry mixing. In such a coating process, the seeds and the at least one hydrogen sulphide donor are mixed, optionally in the presence of at least one formulating agent as set forth above, and/or at least one additional agriculturally active agent. In the mixing process, the ingredients can be added either in combination or consecutively. Preferably, at least one auxiliary agent, chosen from the group consisting of water, oil of plant, animal or synthetic nature, polymers, organic solvents or aqueous solutions is added at any time during the mixing process. If any one of the ingredients selected from the at least one hydrogen sulphide donor and the at least one formulating agent which is optionally present and/or at least one agriculturally active agent which is optionally present are a liquid, the mixing process is also referred to as "wet mixing". If all of the ingredients selected from the at least one hydrogen sulphide donor and the at least one formulating agent which is optionally present and/or at least one agriculturally active agent which is optionally present are solid, the mixing process is also referred to as "dry mixing". If desired, the process includes the step of applying heat and/or reduced pressure during mixing or after mixing is completed.

Applying heat and/or reduced pressure after mixing is completed is especially preferential in the case when the auxiliary agent is or contains water. The process may also optionally include at least one drying step, wherein the at least one drying method is selected from the group consisting of heating, hot air, reduced pressure, IR drying, freeze drying, drying at ambient conditions (e.g. on the air at ambient pressure and temperature). The process can be carried out in any equipment suitable for such mixing, such as tumbling mixers, shear mixers employing rotating shapes, Z-blades, ribbon blades, drum mixers, orbiting screws, pan mixers, Muller mixers, Auger mixers, spinning disc distribution mixers, impellers, air lift mixers, fluidized bed mixers, rotor-stator mixers, hopper discharge blenders and stockpile blenders, free fall mixer (tumble mixer, stagger mixers, mixing pear, conical-, dual conical-, V-mixer, tetrahedral mixer). The process may also optionally include at least one cooling step.

Other processes according to the first section of the present invention to coat the seeds with one or more layers comprising the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent may comprise compression and/or fluid bed methods.

In a preferred embodiment of the first section of the invention, the process for manufacturing the seed composition comprising the seeds and the at least one hydrogen sulphide donor according to the invention comprises formulating the composition comprising the seeds, the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent by extrusion.

In a very preferred embodiment of the first section of the invention, the process for manufacturing the composition comprising the seeds and the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent comprises the step of rolling the seeds into/with a solid, preferably a powder, wherein the solid consists of the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent. Preferably, no liquids are added during this process. The seeds produced by this process possess a film consisting of the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent, formed as a result of Van der Waal forces.

In another very preferred embodiment of the first section of this invention, the process for manufacturing the seed composition according to the invention comprises the steps of mixing pre-wetted seeds with water or another suitable liquid auxiliary agent, and then mix the pre-wetted seeds with a dry seed-coating composition consisting of the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent.

Generally, in the process for manufacturing the seed composition according to the first section of the invention more than one process step can be employed.

In another preferred aspect if the first section of the present invention, the process is carried out such that the seed composition obtained by the process has a H₂S release-rate from 0.001 to 100 ppm/day. Generally, the composition has a H₂S release-rate of the claimed composition is equal to or less than 100 ppm/day. Preferably, the H₂S release-rate is equal to or less than 10 ppm/day. Most preferably, the H₂S release-rate is equal to or less than 1 ppm/day. Generally, the H₂S release-rate is equal to or higher than 0.001 ppm/day. Preferably, the H₂S release-rate is equal to or higher than 0.005 ppm/day. Most preferably, the H₂S release-rate is equal to or higher than 0.01 ppm/day.

In any of the aspects according to the first section of the invention concerning processes for coating seeds with the at least one hydrogen sulphide donor and optionally at least one formulating agent and/or auxiliary agent and/or agriculturally active agent, the term "coated" also denotes partial coating of the seed kernels or the formation of a less well defined coating in which distinct layers cannot be identified. Such coated seeds may also include encrusted seeds or partially encrusted seeds.

In a preferred embodiment of the first section of the invention, the process conditions for mixing and/or coating and/or extruding are suitably selected such that the preferred water content, H₂S release-rate and S -content as set forth above for the composition according to the invention is realized. According to the first section of the present invention, the composition comprising the seeds, the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one auxiliary agent and/or the at least one additional agriculturally active agent is used by applying the composition to the soil.

Generally, in the first section of the invention, the seed composition according to the invention containing the hydrogen sulphide donor is applied to the soil at a daytime temperature ("application temperature", measured in the shade at the zenith of the sun) of equal to or higher than 0°C. More preferably, the application temperature is equal to or higher than 5°C. Most preferably, the application temperature is equal to or higher than 8°C. The application temperature is generally equal to or lower than 40 °C. More preferably, the application temperature is equal to or lower than 30°C. Even more preferably, the application temperature is equal to or lower than 27 °C.

In one embodiment according to the first section of the present invention, the seed coating or seed crust has a thickness of from 0.001 mm to 5 mm.

Generally, the seed coating or crust thickness is equal to or greater than 0.001 mm. More preferably, the seed coating or crust thickness is equal to or greater than 0.01 mm. Even more preferably, the seeds coating or crust thickness is equal to or greater than 0.05 mm. Generally, the seed coating or crust thickness is equal to or lower than 5 mm. More preferably, the seed coating or crust thickness is equal to or lower than 4 mm. Even more preferably, the seed coating or crust thickness is equal to or lower than 3 mm. Most preferably, more preferably, the seed coating or crust thickness is equal to or lower than 2 mm.

The thickness of the seed coating is determined by calculating the surface area of a batch of seeds to be coated, and, the net weight of ingredients to be coated on the seeds, assuming the coating is substantially uniform. The uniformity of the coating is visually determined by sectioning seeds and examining the cross-sections. This method is particularly applicable to very small seeds about 1 mm in average diameter. Larger seeds are sectioned and the thickness of the coating measured under the microscope.

The application of compositions, and compositions especially suitable, to be applied to soil for melioration, is described in the following paragraphs denoted as "second section".

In a second section of the present invention, invention concerns a method of use of a soil meliorating composition comprising at least one hydrogen sulphide donor; such a soil meliorating the composition is applied to the soil to enhance plant growth, seed germination and/or photosynthesis of plants. Such a soil meliorating composition generally does not comprise seeds. The method provides a release, preferably controlled release, of a suitable amount of gaseous H2S and/or dissolved H2S and/or an aqueous solution containing S ^" when the composition is brought into the soil, which is beneficial to the growth of crops at various growth and germination stages. Often, the release of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" is supported by contact with environmental water or controlled irrigation. The presence of a suitable amount of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" at various stages of the germination of the seed and early growth of the seedling and/or plant improves germination speed, quality and resistance of the seedling and/or plant to adverse conditions, such as adverse climate conditions, use of herbicides or other chemicals on the crop, exposure to pathogens or pests, salinity or osmotic stress. The method allows for controlled application of H2S and/or dissolved H2S and/or an aqueous solution containing S ^" at various stages of germination and seedling and/or plant growth, circumventing issues of handling of toxic gaseous H2S or toxic, often fast decomposing solutions of H2S donors, dosage problems or the need for multiply repeated treatment of e.g. seeds or seedlings and/or plants after sowing or planting. The invention further concerns a soil meliorating composition comprising at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent.

The second section of the invention further concerns a process for the manufacture of a composition comprising at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent, wherein the process comprises at least one of the following steps : precipitating, co- precipitating, mixing, milling, drying, slurrying, melting, heating, extruding, cooling, coating, spraying and spray-drying.

The term "hydrogen sulphide donor" as used in the second section of the invention is identical to the definition set forth above.

In one embodiment of the second section of the invention, the soil meliorating compositionfurther comprises at least one formulating agent. The at least one formulating agent generally is selected from the group consisting of a binder, a surfactant, a polymer, a cellulose derivative, a surfactant, a fat or an oil, an organic salt or an inorganic salt. The at least one formulating agent is generally selected to be compatible with an agricultural use. Preferably, the at least one formulating agent is selected from the group consisting of

polysaccharides, polysaccharide derivatives, super-absorbent polymers, water- insoluble polymers, water-soluble polymers and biodegradable polymers, gypsum, phosphor salts, clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers, surfactants (surface-active agents), which may be an

emulsifying, dispersing or wetting agent of the ionic or nonionic type; fillers and plasticizers, or polyelectrolyte complexes. More preferably, the at least one formulating agent is selected from the group consisting of polyesters, polyether esters, polyanhydrides, polyester urethanes, polyester amides; polyvinyl acetates; polyvinyl acetate copolymers; polyvinyl alcohols and tylose; polyvinyl alcohol copolymers; polyvinylpyrrolidones; guar derivatives (e.g. guar galactomannan); sugars, in particular polysaccharides, including starches, modified starches and starch derivatives, dextran, maltodextrins, dextrin, alginates, chitosanes and celluloses, cellulose esters, cellulose ethers and cellulose ether esters including ethylcelluloses, methylcelluloses, hydroxymethylcelluloses,

hydroxypropylcelluloses and carboxymethylcellulose; fats; oils; proteins, including casein and caseinate salts, gelatin and zeins; gum arables; shellacs; vinylidene chloride and vinylidene chloride copolymers; lignosulfonates, in particular calcium lignosulfonates; polyacrylates, polymethacrylates and acrylic copolymers; polyvinylacrylates; polyethylene oxide; polybutenes,

polyisobutenes, polyethylene glycol, polystyrene, polyethyleneamines, polyethylenamides; acrylamide polymers and copolymers; polyhydroxyethyl acrylate, methylacrylamide monomers; polychloroprene; latex; styrene-acrylate based copolymers; wood flours, wood pulp, paper pulp, peat, cereal flours, tree bark mill, wood meal and nut shell meal, activated carbon, fine-grain inorganic solids, silica gels, silicates, clays, vermiculite, chalk, diatomaceous earth, calcium carbonate, magnesium carbonate, dolomite, magnesium oxide, potassium phosphate, titanium dioxide, mica, calcium sulfate and the like; clays and inorganic solids such as calcium bentonite, kaolin, china clay, talc, perlite, mica, vermiculite, silicates, quartz powder, montmorillonite, attapulgite, bole, loess, limestone, lime and mixtures thereof; cereal flours, which includes wheat flour, oat flour and barley flour. Most preferred formulating agents are cellulose derivatives, such as methyl cellulose. In another embodiment of the second section of the invention, at least one pH regulating formulating agent is comprised in the soil meliorating composition such as lime. This can serve to aid to control H2S release, e.g. in acid soils.

In the method of use according to the second section of the present invention the soil to which the soil meliorating composition containing a hydrogen sulphide donor is applied generally is used to grow crops, for example from seeds or seedlings. Crops for whose cultivation the method of use is beneficial include any crops that are suitable for the production of plants, preferably for human or animal consumption, or for further manufacture of industrially applicable products such as fibres, textiles, fuels or polymers.

Generally, the invention is not limited to specific species of crops. The species include fruits such as pear-like fruits, stone fruits, and soft fruits (apple, pear, plum, peach, Japanese apricot, prune, almond, cherry, strawberry, raspberry, black berry, tomato, pepper), cereals, roots, legumes, tubers such as beets and potatoes, herbs, spices, camphor trees (avocado, cinnamon, camphor, etc.), ornamental plants, fiber plants such as flax or cotton, drug plants and oil producing plants, for example rape, canola, mustard, poppy, olive, sunflower, coconut, castor, cocoa bean, peanut and soybean; tobacco, nuts, coffee, sugar cane, tea, grapevine, hop and banana. More preferably, the species include cereals. Even more preferably, the crops include rice, wheat, rye, maize, quinoa, oats, barley, millet, sorghum, teff, triticale, spelt and buckwheat. The most preferred cereal species are rice and maize. Other preferred crops include potato, carrot, sweet potato, sugar beet, bean, pea, chicory, lettuce, cabbage, cauliflower, broccoli, turnip, radish, spinach, asparagus, onion, garlic, eggplant, pepper, celery, canot, squash, pumpkin, zucchini, cucumber, apple, pear, quince, melon, plum, cherry, peach, nectarine, apricot, strawberry, grape, raspberry, blackberry, pineapple, avocado, papaya, mango, banana, soybean, tomato and raspberries. The method of use may be applied to soil on which more than one species of crop is grown. According to the claimed method of use, the soil meliorating composition comprising at least one hydrogen sulphide donor and optionally at least one formulating agent and optionally at least one additional agriculturally active agent and optionally at least one auxiliary agent generally may be applied to the soil before, during or after sowing and/or planting. The application to the soil after sowing and/or planting is preferred.

In the method of use according to the present invention the soil to which the composition containing a hydrogen sulphide donor is applied generally is used to grow crops, for example from seeds or seedlings. Crops for whose cultivation the method of use is beneficial include any crops that are suitable for the production of plants, preferably for human or animal consumption, or for further manufacture of industrially applicable products such as fibres, textiles, fuels or polymers. Generally, the invention is not limited to specific species of crops. The species include fruits such as pear-like fruits, stone fruits, and soft fruits (apple, pear, plum, peach, Japanese apricot, prune, almond, cherry, strawberry, raspberry, black berry, tomato, pepper), cereals, roots, legumes, tubers such as beets and potatoes, herbs, spices, camphor trees (avocado, cinnamon, camphor, etc.), ornamental plants, fibre plants such as flax or cotton, drug plants and oil producing plants, for example rape, canola, mustard, poppy, olive, sunflower, coconut, castor, cocoa bean, peanut and soybean; tobacco, nuts, coffee, sugar cane, tea, grapevine, hop and banana. More preferably, the species include cereals. Even more preferably, the crops include rice, wheat, rye, maize, quinoa, oats, barley, millet, sorghum, teff, triticale, spelt and buckwheat. The most preferred cereal species are rice and maize. Other preferred crops include potato, carrot, sweet potato, sugar beet, bean, pea, chicory, lettuce, cabbage, cauliflower, broccoli, turnip, radish, spinach, asparagus, onion, garlic, eggplant, pepper, celery, canot, squash, pumpkin, zucchini, cucumber, apple, pear, quince, melon, plum, cherry, peach, nectarine, apricot, strawberry, grape, raspberry, blackberry, pineapple, avocado, papaya, mango, banana, soybean, tomato and raspberries. The method of use may be applied to soil on which more than one species of crop is grown. According to the claimed method of use, the soil meliorating composition comprising at least one hydrogen sulphide donor and optionally at least one formulating agent and optionally at least one additional agriculturally active agent and optionally at least one auxiliary agent generally may be applied to the soil before, during or after sowing and/or planting. The application to the soil after sowing and/or planting is preferred.

In another embodiment of the second section of the invention, the soil meliorating composition further comprises at least one additional agriculturally active agent. As used herein, the term "agricultural active agent" denotes any chemical element, molecule, or compound, or mixture thereof, which has properties which enhance the efficiency of the agricultural activity. For example, agricultural active agent can enhance or control a biological activity in a seed, a plant, or a disease or pest of a seed or plant; or function as antidote against herbicides. Such agricultural active agents include, but are not limited to, pesticides, herbicides, fertilizers including nutrients (macronutrients and/or micronutrients), such as ammonium sulfate, ammonium phosphate, herbicide antidotes such as oximes, ammonium nitrate, ureas and mixtures thereof, plant growth regulators, drugs, dyes, biological attractants, scents and pheromones. Preferred fertilizers are humus, manure or urea.

In a further embodiment of the second section of the invention, in the claimed method of use, the composition which is being applied to the soil according to the method of use further comprises at least one auxiliary agent. The term "auxiliary agent" is intended to denote in particular an agent fostering the applicability selected from the group consisting of water, oil of plant, animal or synthetic nature, organic solvents or aqueous solutions. An auxiliary agent may be advantageously present in the formulation process of the composition, e.g. to avoid dusting or enhance adhesion. In certain aspects, the optional auxiliary agent can also be fully or partly removed during the process according to the invention for manufacturing the composition containing the hydrogen sulphide donor.

In a preferred aspect of the second section of the invention, the soil meliorating composition is solid.The method of use according to the second section of the invention, generally is performed by applying the composition containing the hydrogen sulphide donor to the soil at a daytime temperature ("application temperature", measured in the shade at the zenith of the sun) of equal to or higher than 0°C. Preferably, the composition is applied to the soil at a daytime soil temperature range of from 0°C to 40°C.

More preferably, the application temperature is equal to or higher than 5°C. Most preferably, the application temperature is equal to or higher than 8°C. The application temperature is generally equal to or lower than 40°C. More preferably, the application temperature is equal to or lower than 30°C. Even more preferably, the application temperature is equal to or lower than 27 °C.

The method of use according to the second section of the invention, generally is performed by applying the composition to the soil such that the S - concentration is in the range of from 0.005 to 0.6 mol/acre. Preferably, the composition is applied to the soil in an amount corresponding to a

S -concentration in the range of from 0.05 to 0.60 mol/acre.

Generally, the S -concentration is equal to or higher than 0.005 mol/acre. More preferably, the S -concentration is equal to or higher than 0.01 mol/acre. Most preferably, the the S -concentration is equal to or higher than 0.02 mol/acre. Generally, the S -concentration is equal to or lower than 0.6 mol/acre. More preferably, the S -concentration is equal to or lower than 0.3 mol/acre. Even more preferably, the S -concentration is equal to or lower than 0.2 mol/acre.

An acre corresponds to 4046.856 m .

In the method of use according to the the second section of the invention, the S -content of the soil meliorating composition generally is from 0.3 wt % to 58 wt %. Often, the S -content of the composition is equal to or higher than 0.3 wt %. More preferably, the S -content of the composition is equal to or higher than 5 wt %. Even more preferably, the S -content of the composition is equal to or higher than 10 wt %. Most preferably, the S -content of the composition is equal to or higher than 20 wt %. Generally, the S -content of the composition is equal to or lower than 58 wt %. More preferably, the S -content of the composition is equal to or lower than 55 wt %. Even more preferably, the S ^"- content of the composition is equal to or lower than 50 wt %. The S -content, expressed as "wt %" (weight percent), is wt % of weight in relation to the weight of the composition, wherein the composition comprises all ingredients such as the at least one hydrogen sulphide donor, optionally the at least one formulating agent, and other optional ingredients such as agriculturally active agents and/or auxiliary agent.

In a particular embodiment of the method of use according to the second section if the invention, the water content of the composition is low. Generally, the water content is equal to or less than 10000 ppm. Preferably, the water content is equal to or less than 8000 ppm. Most preferably, the water content is equal to or less than 5000 ppm. Generally, the water content is equal to or higher than 100 ppm. In some cases, a water content of equal to or higher than 500 ppm is preferred. The water content may also be equal to or higher than 1000 ppm. If the process allows, a water content of even less than 100 ppm is achieved; often, the water content is then equal to or higher than 5 ppm. In a most preferred embodiment, the water content is from 100 ppm to 10000 ppm. The water content, expressed as "ppm" is ppm="parts per million" of weight in relation to the weight of the composition, wherein the composition comprises all ingredients such as the at least one hydrogen sulphide donor, optionally the at least one formulation, and other optional ingredients such as agriculturally active agents and/or auxiliary agent. In one aspect of the second section of the present invention, in the method of use according to the invention, the soil meliorating composition has an H₂S release-rate of the claimed composition is equal to or less than 100 ppm/day. Preferably, the H₂S release-rate is equal to or less than 10 ppm/day. Most preferably, the H₂S release-rate is equal to or less than 1 ppm/day. Generally, the H₂S release-rate is equal to or higher than 0.001 ppm/day. Preferably, the H₂S release-rate is equal to or higher than 0.005 ppm/day. Most preferably, the H₂S release-rate is equal to or higher than 0.01 ppm/day.

The second section of the invention also concerns a soil meliorating composition comprising at least one hydrogen sulphide donor and at least one formulating agent and/or at least one additional agriculturally active agent and/or at least one auxiliary agent. The terms "hydrogen sulphide donor", "formulating agent", "agriculturally active agent" and "auxiliary agent" have the same meaning as set forth above for the claimed method of according to the invention, and its different aspects and embodiments. The same preferences for "hydrogen sulphide donor", "formulating agent", "agriculturally active agent" and

"auxiliary agent" as set forth above apply as for the claimed method of use according to the invention, and its different aspects, preferences and

embodiments. The application temperature, S -concentration in mol/acre and crops for whose cultivation the composition according to the invention can be used, are as described above for the composition used in the method of use according to the invention. The composition according to the invention preferably is a solid.

In the soil meliorating composition according to the second section of the present invention the S -content of the composition, comprising the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one additional agriculturally active agent and/or the at least one auxiliary agent, generally is from 0.3 wt % to 58 wt %. Often, the S ^"-content of the composition is equal to or higher than 0.3 wt %. More preferably, the S ^"- content of the composition is equal to or higher than 5 wt %. Even more preferably, the S -content of the composition is equal to or higher than 10 wt %. Most preferably, the S -content of the composition is equal to or higher than 20 wt %. Generally, the S -content of the composition is equal to or lower than 58 wt %. More preferably, the S -content of the composition is equal to or lower than 55 wt %. Even more preferably, the S -content of the composition is equal to or lower than 50 wt %. The S ^"-content, expressed as "wt %" (weight percent), is wt % of weight in relation to the weight of the composition, wherein the composition comprises all ingredients such as the at least one hydrogen sulphide donor, optionally the at least one formulating agent, and other optional ingredients such as agriculturally active agents and/or auxiliary agent.

The water-content of the soil meliorating composition according to the second section of the invention, comprising the at least one hydrogen sulphide donor and optionally the at least one formulating agent and/or the at least one additional agriculturally active agent and/or the at least one auxiliary agent, is generally low. Generally, the water content of the claimed composition is equal to or less than 10000 ppm. Preferably, the water content is equal to or less than 8000 ppm. Most preferably, the water content is equal to or less than 5000 ppm. Generally, the water content is equal to or higher than 100 ppm. In some cases, a water content of equal to or higher than 500 ppm is preferred. The water content may also be equal to or higher than 1000 ppm. If the process allows, a water content of even less than 100 ppm is achieved; often, the water content ist then equal to or higher than 5 ppm. In a most preferred embodiment, the water content is from 100 ppm to 10000 ppm. The water content, expressed as "ppm" is ppm="parts per million" of weight in relation to the weight of the

composition, wherein the composition comprises all ingredients such as the at least one hydrogen sulphide donor, optionally the at least one formulating agent, and other optional ingredients such as agriculturally active agents and/or auxiliary agent.

In a particular embodiment of the second section of the present invention, the soil meliorating composition according to the invention consists of a core and at least one layer. Preferably the core and the at least one layer each comprise independently either the least one hydrogen sulphide donor or the at least one formulating agent and/or optionally at least one additional agriculturally active agent, or the least one hydrogen sulphide donor and the at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent. Suitably, the core comprises at least the hydrogen sulphide donor and at least one layer comprises the at least one formulating agent and/or optionally at least one additional agriculturally active agent, and the at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent. In one aspect of the second section of the present invention, the claimed composition is applied to the soil, i.e. the composition according to the invention is used in the method of use according to the invention.

The H₂S release-rate of the composition according to the second section of the present invention is generally equal to or less than 100 ppm/day, wherein one day denotes 24 hours. Preferably, the H₂S release-rate is equal to or less than 10 ppm/day. Most preferably, the H₂S release-rate is equal to or less than 1 ppm/day. Generally, the H₂S release-rate is equal to or higher than 0.001 ppm/day. Preferably, the H₂S release-rate is equal to or higher than 0.005 ppm/day. Most preferably, the H₂S release-rate is equal to or higher than 0.01 ppm/day.

The H₂S release-rate for the the composition according to the second section of the present invention can be determined by suitable detection methods such as "UOP9-85 Hydrogen Sulphide in Gases by the Tutwiler Method"; UOP Method 212, "Hydrogen Sulphide, Mercaptan Sulfur and Carbonyl Sulphide in Hydrocarbon Gases by Potentiometric Titration", H2S probes which are commercially available, such as GA24XT-H, precipitation or gravimetric methods (e.g. copper ion solution titration), methylene blue method; or H2S adsorption in Cd- or Zn-acetate solution with subsequent iodometric analysis. Preferably, the H2S release rate is measured by H2S probe or precipitation of copper sulphide with gravimetrical analysis.

The second section of the invention also concerns a process for the manufacture of a soil meliorating composition comprising at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent, wherein the process comprises at least one of the following steps :

precipitation, co-precipitation, mixing, milling, drying, slurrying, melting, heating, extruding, cooling, coating, spraying, spray-drying. Generally, more than one process step can be employed.

In one aspect of the second section of the invention, the process for the manufacture of the soil meliorating composition according to the invention comprises mixing the at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent. In the mixing process, the ingredients can be added either in combination or consecutively. Optionally, at least one auxiliary agent, preferably chosen from the group consisting of water, oil of plant, animal or synthetic nature, organic solvents or aqueous solutions is added at any time during the mixing process. If any one of the ingredients, being the at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent, is a liquid, the mixing process is also referred to as "wet mixing". If all of the ingredients, being the at least one hydrogen sulphide donor and at least one formulating agent and/or optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent is solid, the mixing process is also referred to as "dry mixing". Dry mixing may include also dusting and milling. If desired, the process also comprises the step of applying heat and/or reduced pressure during mixing and/or after mixing is completed. Applying heat and/or reduced pressure during mixing and/or after mixing is completed is especially preferential in the case when the auxiliary agent is or contains water. The process may also optionally include at least one drying step, wherein the at least one drying method is preferably selected from the group consisting of heating, hot air, reduced pressure, IR drying, freeze drying, drying at ambient conditions (e.g. on the air at ambient pressure and temperature). The process may also include optionally at least one cooling step. The mixing can be carried out in any equipment suitable for such mixing, such as tumbling mixers, shear mixers employing rotating shapes, drum mixers, Z-blades, ribbon blades, orbiting screws, pan mixers, Muller mixers, Auger mixers, spinning disk distribution mixers, impellers, air lift mixers, fluidized bed mixers, rotor-stator mixers, hopper discharge blenders and stockpile blenders, free fall mixer (tumble mixer, stagger mixers, mixing pear, comical-, dual conical-, V-mixer, tetrahedral mixer). Most preferably, the equipment is chosen such that no or essentially no segregation of the at least one hydrogen sulphide donor and other optionally present ingredients occurs, resulting in a homogenous or essentially homogenous blend.

In one aspect of the second section of the invention, the process for manufacturing the composition comprising at least one hydrogen sulphide donor provides a composition with the specific H₂S release-rate, S -content and water content as set forth above for the composition according to the invention.

Process conditions and steps for the process for manufacturing the composition according to the second section of the invention are preferably are suitably chosen; for example, formulating agent may be chosen such as to control the H2S -release under the agricultural conditions; layers may be formed in the product with formulating agents which will impact the H2S-release; heat and/or pressure may be chosen such that water is removed from the product to reach the targeted water content; the ratio of ingredients may be optimized such that the product can be applied in a desirable concentration per soil surface; manufacturing conditions and apparatus may be selected such that the product acquires properties like compactness, hardness, solubility etc. which will impact the dosage and release of the active substance or active substances - e.g. rotating drums will, at relevant speed, time, temperature and/or pressure result in a product with a specific compactness. Generally, the process for manufacturing the composition comprising at least one hydrogen sulphide donor according to the second section of the invention comprises at least one step selected from the group consisting of : preparing solutions, slurries or pastes of at least one ingredients, wet or dry mixing, extruding, coating, precipitating, co-precipitating, mixing, milling, drying, slurrying, melting, heating, extruding, cooling, coating, spraying and spray-drying. Preferred process steps are mixing and extruding. Generally, more than one process step can be employed. In a most preferred process, the hydrogen sulphide donor is mixed with a binder, preferably lignosulfonate, and a filler material, preferably calcium carbonate, clay or anhydrite calcium sulfate, in a dry mixing process.

In another preferred aspect, the process for manufacturing the composition comprising at least one hydrogen sulphide donor according to the second section of the invention is carried out such that the composition obtained by the process has a H₂S release-rate from 0.001 to 100 ppm/day. Generally, the composition has a H₂S release-rate of the claimed composition is equal to or less than 100 ppm/day. Preferably, the H₂S release-rate is equal to or less than 10 ppm/day. Most preferably, the H₂S release-rate is equal to or less than 1 ppm/day.

Generally, the H₂S release-rate is equal to or higher than 0.001 ppm/day.

Preferably, the H₂S release-rate is equal to or higher than 0.005 ppm/day. Most preferably, the H₂S release-rate is equal to or higher than 0.01 ppm/day.

Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

The following examples describe the invention more detail without intending to limit it.

Example 1: A seed composition 6,75 g of CaS (corresponding to a S ^" amount of 3 g) are slurried in 6 mL methanol. 3 g of polyvinyl alcohol and 3 g hydroxypropylcellulose in 6 mL of methanol are added and the mixture is mixed with 91 g of rice seeds in a rotary coating machine. After an application time of about 5 minutes, the seeds are dried in a fluid bed dryer. The coated seeds display an enhanced rate of germination when tested in the field.

Example 2: A soil meliorating composition

45 g of CaS and 50 g of calcium lignosulfonate are mixed in a rotary mixer. A mixture of 5 g polyvinyl alcohol in 11 ml MeOH is sprayed onto the rotating mixture. After finished application, the mixture is dried in a fluid bed dryer. The soil meliorating composition displays a germination and growth enhancing effect when applied to the soil which is then planted with rice seeds.

Claims

C L A I M S

1. A method of use of hydrogen sulphide for enhancing melioration of soil, plant growth, seed germination and/or photosynthesis, wherein the hydrogen sulphide is provided in the form of a hydrogen sulphide donor.

2. The method of claim 1, wherein the at least one hydrogen sulphide donor preferably is a solid, and wherein a) The at least one hydrogen sulphide donor is comprised in a composition which is applied to the soil, or

b) The at least one hydrogen sulphide donor is comprised in a seed composition comprising seeds

3. A composition comprising at least one hydrogen sulphide donor and at least one additional agent selected from the group consisting of seeds, a formulating agent, at least one additional agriculturally active agent and at least one auxiliary agent.

4. The composition of claim 3 which is a seed composition comprising seeds and at least one hydrogen sulphide donor.

5. The composition of claim 3 which is a soil meliorating composition comprising at least one hydrogen sulphide donor and at least one additional agent selected from the group consisting of a formulating agent, at least one additional agriculturally active agent and at least one auxiliary agent.

6. The seed composition according to claims 3 or 4, or the soil meliorating composition sulphide according to claim 3 or 5, wherein the hydrogen sulphide donor is selected from the group consisting of metal sulphide salts and metal hydro sulphide salts.

7. The seed composition according to any one of claims 3, 4 and 6, or the soil meliorating composition sulphideaccording to claim 3, 5 or 6, wherein the hydrogen sulphide donor is selected from the group consisting of CaS, KHS, NaHS, Na₂S, MgS, SrS, BaS, SiS.

8. The seed composition according to any one of the claims 3, 4, 6 and 7, wherein the water content of the composition is from 0 to 10000 ppm.

9. The seed composition of any one of claims 3, 4 and 6 to 8, wherein the seeds are selected from the group of cereals, tubers, roots, legumes, fruits, vegetables, fibre plants, drug plants and oil plants.

10. The seed composition of any one of the claims 3, 4 and 6 to 9, wherein the seeds are at least partially coated with at least one coating layer, wherein the at least one coating layer comprises either the at least one hydrogen sulphide donor or optionally one or more formulating agent and/or at least one additional agriculturally active agent and/or at least one auxiliary agent, or the at least one hydrogen sulphide donor and the at least one formulating agent and/or at least one additional agriculturally active agent and/or at least one auxiliary agent.

11. The seed composition of any one of the claims 3, 4 and 6 to 10, wherein the composition has a H₂S release-rate from 0.001 to 100 ppm/day.

12. A process for the manufacture of a seed composition according to any one of claims 3, 4 and 6 to 11 comprising seeds and at least one hydrogen sulphide donor and optionally one or more formulating agent formulating agent and optionally one or more agriculturally active agent and optionally at least one auxiliary agent, wherein the seeds are either mixed with the at least one hydrogen sulphide donor and optionally the at least one formulating agent and optionally one or more agriculturally active agent and optionally at least one auxiliary agent, or wherein the seeds are coated with at least one layer comprising the at least one hydrogen sulphide donor and optionally the at least one formulating agent and optionally one or more agriculturally active agent and optionally at least one auxiliary agent wherein the process comprises one or more of the following steps : precipitation, co-precipitation, mixing, dry mixing, wet mixing, dusting, milling, dipping, misting, drying, slurrying, melting, heating, extruding, cooling, coating, spraying and spray-drying.

13. The soil meliorating composition according to any one of claims 3 and 5 to 7, comprising at least one sulphideformulating agent wherein the at least one least one formulating agent is comprised in the composition, wherein the at least one formulating agent is selected from the group consisting of a binder, a polymer, a surfactant, a cellulose derivative, an organic salt or an inorganic salt, wherein the at least one formulating agent preferably is selected from the group consisting of polysaccharides, polysaccharide derivatives, super-absorbant polymers, water-insoluble polymers, water-soluble polymers and biodegradable polymers, gypsum and phosphor salts.

14. The soil meliorating composition sulphideaccording to any one of claims 3, 5 to 7 or 13, wherein the water content of the composition is from 100 to 10000 ppm.

15. A process for the manufacture of a soil meliorating composition sulphideaccording to any one of claims 3, 5 to 7 and 13 to 14 comprising at least one hydrogen sulphide donor and at least one additional agent and optionally at least one additional agriculturally active agent and/or optionally at least one auxiliary agent, wherein the process comprises at least one of the following steps : precipitating, co-precipitating, wet mixing, dry mixing, milling, drying, slurrying, melting, heating, extruding, cooling, coating, spraying, spray-drying.