Fertilizer containing copper source

Abstract

The present invention provides the use of Cu2SO3.CuSO3.2 2H2O as a fertilizer for providing copper to plants. Fertilizer compositions and methods of nutrition of plants are disclosed.

Description

Technical Field

[0001] The present invention relates to a fertilizer composition comprising Chevreul's salt as a copper source and optionally other macronutrients and micronutrients, and to the use of Chevreul's salt for fertilizing plants. Background Art

[0002] Copper (Cu) is an essential element for many functions in plants, such as chlorophyll production, protein synthesis and respiration. Copper deficiency in plant nutrition can lead to severe yield losses. Copper deficiency manifests itself as yellowing and twisting of young leaves, curling of leaf tips, weakness and wilting at heading, damaged spikelets, bending of growth tips and stems, or melanosis of the stems. Therefore, copper-containing fertilizers are widely used to improve the yield and quality of crop production (Canadian Journal of Plant Science, 2006, 86(3), 605-619).

[0003] Copper deficiency in crops is usually treated by applying copper sulfate or Cu 2+ Chelated forms (e.g. EDTA Cu 2+ For example, patents TR2017007417, WO2015036375, BR2010003875, PL213508 and PL212335 relate to the composition, preparation and use of copper-containing soluble fertilizers.

[0004] All of these fertilizers are water-soluble and therefore easily leached from the root zone or washed off the leaves after foliar application. Copper fertilizers are therefore dosed in considerable excess compared to actual needs, and the economic and ecological use of these fertilizers is not always favorable. For example, copper sulfate is applied to the soil in doses of 3.5 to 15 kg Cu / ha. Copper oxychloride is a gradual release fertilizer most often applied in the form of a suspension concentrate and is still used in high doses (up to 2 kg Cu / ha). Summary of the invention

[0005] An effective way to provide copper to plants is to use slow-release fertilizers. The copper ions may be contained in the fertilizer in their insoluble chemical form, but are gradually released from this insoluble form by biological or chemical processes, thus becoming available for plant uptake. The main problem is to find a form of copper that provides the correct release rate corresponding to plant consumption, thus allowing the dose required to apply the copper to be minimized.

[0006] One aspect of the invention is the use of Cu2SO3.CuSO3.2H2O (so-called Chevreul salt) as a fertilizer for providing copper to plants.

[0007] One aspect of the present invention is also a method for plant nutrition, comprising the step of applying Cu2SO3.CuSO3.2H2O to seeds, plants, fruits or soil.

[0008] Chevreul salt (Cu2SO3·CuSO3·2H2O) contains copper in two oxidation states: Cu 2+ and Cu + , is a very water-insoluble substance. In the metallurgical industry, its low solubility is used to remove 2+ The preparation, structure and properties of Chevreul salts are known (Silva LA, Andrade JB, J. Braz. Chem. Soc., 2004, 15 (2), 170-177). This substance can be prepared by several methods, usually by using S 4+ Compounds (SO2, HSO3 – 、SO3 2– etc.) in aqueous solution at elevated temperatures to reduce Cu 2+ Compounds are prepared (eg, Calban T. et al., Chem. Eng. Comm. 2009, 196, 1018-1029).

[0009] Within the framework of the present invention, it was surprisingly found that the very water-insoluble Chevreul salts release copper at the correct rate for consumption by plants and provide sufficient amounts of copper even at significantly lower application rates than copper fertilizers currently used in the art.

[0010] Fertilizer compositions containing the compound Cu2SO3.CuSO3.2H2O generally contain solvents (especially water), surfactants, rheology modifiers, antioxidants, defoamers and optionally other auxiliary substances known in the formulation art. Chevreul salts can generally be contained in fertilizer compositions in suspended or granular form.

[0011] The fertilizer composition may also contain one or more sources of nutrients N, P, K, Ca, Mg, S, B, Cl, Fe, Mn, Mo, Ni and Zn. Preferably, the nutrient source (nutrient source) can be selected from: ammonium nitrate, potassium nitrate, calcium nitrate, calcium carbonate, magnesium carbonate, dolomitic limestone, urea, ammonium sulfate, calcium dihydrogen phosphate, calcium sulfate dihydrate, ammonium dihydrogen phosphate, potassium chloride, potassium sulfate, kainite (KCl·MgSO4·3H2O), magnesium sulfate, magnesium sulfate heptahydrate, magnesium sulfate monohydrate, ferrous sulfate, ferrous sulfate heptahydrate, Fe 3+Complex with ethylenediaminetetraacetate (EDTA), complex of boric acid and ethanolamine, manganese(II) chloride, manganese(II) chloride dihydrate, manganese(II) chloride tetrahydrate, manganese(II) sulfate, manganese(II) sulfate monohydrate, manganese(II) sulfate tetrahydrate, ammonium molybdate, sodium molybdate, nickel sulfate, nickel sulfate hexahydrate, nickel sulfate heptahydrate, zinc sulfate, Zn 2+ Complex with EDTA, zinc sulfate hexahydrate, zinc sulfate heptahydrate.

[0012] The fertilizer composition according to the present invention may preferably contain one or more sources of the nutrients N, K, S, B and Zn. More preferably, the fertilizer composition contains one or more of the following: ammonium nitrate, potassium nitrate, calcium nitrate, urea, ammonium sulfate, potassium sulfate, magnesium sulfate heptahydrate, a complex of boric acid and ethanolamine, Zn 2+ Complex with EDTA.

[0013] Surfactants include dispersants, wetting agents and emulsifiers of ionic or nonionic nature. Examples may be salts of naphthalenesulfonic acid, phenolsulfonic acid and ligninsulfonic acid, polycondensates of ethylene oxide with fatty alcohols or amines, substituted phenols (preferably alkylphenols and arylphenols), salts of sulfosuccinates, salts of alkylbenzenesulfonic acids, taurine derivatives (preferably alkyl taurates), polyethylene glycol sorbitan monolaurate, polyethylene glycol sorbitan monopalmitate, polyethylene glycol sorbitan monostearate, polyethylene glycol sorbitan monooleate, phosphate esters of polyethoxylated alcohols or phenols, fatty acid esters of polyols and derivatives of the above compounds containing sulfate, sulfonate or phosphate functional groups. The surfactant content in the mixture may preferably be in the range of 2% to 50% by weight.

[0014] Antioxidants are any substances suitable for use in agriculture that have the ability to stabilize Cu2SO3·CuSO3·2H2O compounds against oxidation. 4+ Compounds such as NaHSO3, Na2SO3, Na2S2O5 or K2S2O5. The antioxidant content in the fertilizer may preferably be in the range of 0.01 wt% to 10 wt%.

[0015] A defoamer (or deaerator) is any substance which reduces the stability of the foam. Silicone-based compounds are particularly preferred.

[0016] Auxiliary substances are colloidal stabilizers, adhesives, binders and rheology modifiers. Preferred auxiliary substances are selected from the group consisting of: hydroxypropyl cellulose, hydroxypropyl methylcellulose, methylcellulose, ethyl methylcellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol, betaine, mannitol, sorbitol, glycerol. In general, Cu2SO3·CuSO3·2H2O can be combined with any liquid or solid auxiliary substances commonly used in fertilizer formulations.

[0017] The fertilizer composition according to the present invention preferably contains 1 to 99 wt% of Cu2SO3·CuSO3·2H2O. When formulated as a wettable powder or water-dispersible granules, the fertilizer composition preferably contains 10 to 95 wt%, more preferably 40 to 95 wt%, or 40 to 80 wt% of Cu2SO3·CuSO3·2H2O. When formulated as a suspension concentrate, the fertilizer composition preferably contains 1 to 50 wt%, more preferably 5 to 30 wt% of Cu2SO3·CuSO3·2H2O.

[0018] The fertilizer composition according to the present invention can be prepared in various forms suitable for direct or diluted application in agriculture, such as granules or microparticles dispersible in water, wettable powders, tablets dispersible in water, suspensions, suspension concentrates, pastes dispersible in water, emulsifiable powders, emulsifiable granules or microparticles, emulsifiable suspension concentrates, microemulsions, colloidal solutions containing nano- or micro-particles of Cu2SO3.CuSO3.2H2O. Wettable powders can be filled into soluble packaging, which can prevent undesirable dusting and possible inhalation by users.

[0019] For the above-mentioned applications, the Chevreul salt Cu2SO3.CuSO3.2H2O should preferably have a particle size of less than 40 μm, preferably less than 8 μm, in an even more preferred embodiment less than 4 μm, and most preferably at most 2 μm, the particle size being determined using laser diffraction (Sympa TEC HELOS / KR). The particle size corresponds to the hydrodynamic mean diameter of the particles determined in the measured dispersion.

[0020] In some embodiments, the fertilizer composition according to the present invention may further include additional active substances, such as insecticides, fungicides, bactericides, attractants, acaricides, pheromones and other biologically active substances. The inclusion of additional active substances can increase the effectiveness of the fertilizer.

[0021] The fertilizer composition according to the present invention can be used to fertilize plants (provide copper to plants) by applying it to the plants, their seeds, fruits or the soil in which the plants grow. Crops that can be fertilized using the fertilizer composition include cotton, flax, grapevines, Rosaceae crops (e.g., apple and pear trees, apricot trees, almond trees and peach trees, strawberries), Ribesioidae, Juglandaceae, Betulaceae, Anacardiaceae, Fagaceae, Moraceae, Oleaceae, Actinidaceae, Lauraceae, Musaceae, Rubiaceae, Theaceae, Sterculiceae, Rutaceae (e.g., lemons, oranges and grapefruits), Solanaceae (e.g., tomatoes, potatoes, peppers), Liliaceae, Asteraceae (e.g., chives), Umbelliferae (e.g., ae), Cruciferae, Graminae (e.g. corn, grasses or cereals such as wheat, barley, oats, rye or triticale), Asteraceae (e.g. sunflower), Poaceae (e.g. rice, sorghum), Cucurbitaceae (e.g. cucumber, pumpkin, melon, squash), Brassicaceae (e.g. cabbage), Cruciferae (e.g. canola), Apiaceae (e.g. carrot, parsley, celery), Alliaceae (e.g. onion), Fabacae (e.g. peanuts), Papilionaceae (e.g. soybean, lentil, pea, beans), Chenopodiaceae (e.g. sugar beet, spinach); general agricultural, technical and forest crops and their transgenic homologs.

[0022] The fertilizer composition according to the invention can preferably be used for fertilizing (supplying copper thereto) cereals, corn, rapeseed, mustard, poppy, sunflower, potato, sugar cane, legumes, grapevines, hops, fruit vegetables and root vegetables.

[0023] In a particularly preferred embodiment, the fertilizer is in the form of a suspension concentrate containing 5 to 30% by weight of Cu2SO3.CuSO3.2H2O, 1 to 10% by weight of a surfactant, 1 to 10% by weight of an auxiliary substance and a solvent. The solvent is preferably water.

[0024] The dosage of Cu2SO3.CuSO3.2H2O, expressed as the dosage of Cu during foliar application, may be in the range of 5 to 750 g / ha, preferably in the range of 10 to 250 g / ha, in an even more preferred embodiment in the range of 25 to 150 g / ha. DETAILED DESCRIPTION

[0025] Example 1

[0026] Preparation of a Suspension Concentrate Containing Cu2SO3·CuSO3·2H2O (Fertilizer Composition A1)

[0027] The Chevreul salts and auxiliary substances listed in Table 1 were mixed with water and the mixture was ground using a laboratory grinder Dyno-mill Multi-lab (Soremat) until the particle size was less than 2 μm. The stable dispersion obtained formed the fertilizer composition A1. Composition A1 contained 50 g / dm 3 The particle size was determined by laser diffraction using a Sympa TEC HELOS / KR device. The particle size values ​​represent the hydrodynamic diameter of the particles in the interval X90.

[0028] Table 1 Fertilizer composition A1

[0029] Compound / Substance weight% <![CDATA[Cu2SO3·CuSO3·2H2O]]> 9.5 Polyvinylpyrrolidone 2.0 Hydroxypropyl Cellulose 1.0 Polyethylene glycol sorbitan monolaurate (Tween 20) 2.0 water 85.5

[0030] Example 2

[0031] Preparation of a Suspension Concentrate Containing Cu2SO3.CuSO3.2H2O and a Source of Additional Nutrients (Fertilizer Composition A4)

[0032] The Chevreul salts and auxiliary substances listed in Table 2 were mixed with water and the mixture was ground using a Dyno-mill Multi-lab (Soremat) until the particle size was less than 2 μm. The particle size was determined as in Example 1. A stable dispersion of the fertilizer composition A2 was obtained.

[0033] The sources of nutrients listed in Table 3 were dissolved in water to obtain fertilizer composition A3.

[0034] The final stable dispersion A4 of the fertilizer was obtained by mixing the fertilizer compositions A2 and A3 in a weight ratio of 0.579:0.421. The obtained fertilizer composition A4 contained 50 g / dm 3Cu.

[0035] Table 2 Fertilizer composition A2

[0036] Compound / Substance weight% <![CDATA[Cu2SO3·CuSO3·2H2O]]> 15 Polyvinylpyrrolidone 2 Hydroxypropyl methylcellulose 1 Polyethylene glycol sorbitan monolaurate (Tween 20) 2 water 80

[0037] Table 3 Fertilizer composition A3

[0038] Compound / Substance weight% Potassium Nitrate 15.5 Boric acid complex with ethanolamine 16.6 Zn-EDTA 14.3 Betaine Hydrochloride 0.6 water 53.0

[0039] Table 4 Fertilizer composition A4

[0040] Compound / Substance weight% <![CDATA[Cu2SO3·CuSO3·2H2O]]> 8.70 Polyvinylpyrrolidone 1.16 Hydroxypropyl methylcellulose 0.58 Polyethylene glycol sorbitan monolaurate (Tween 20) 1.16 Potassium Nitrate 6.63 Boric acid complex with ethanolamine 6.99 Zn-EDTA 6.02 Betaine Hydrochloride 0.25 water 68.61

[0041] Example 3

[0042] It was tested whether the fertilizer composition according to the invention containing Chevreul salt as active ingredient can be used in combination with Cu 2+ The water-soluble chelate form of copper was absorbed by the leaves at comparable levels. Therefore, the same dose of copper was applied in these two different forms under the same conditions and the uptake of copper by the plants was compared. The model crop was rapeseed (Brassica napus subsp. napus L.), winter type.

[0043] The experiment was a small plot experiment, in which one application plot was 4m 2 , for each copper source type two plots were tested and mixed plant samples were collected from both plots for analysis. Two fertilizer compositions (different copper sources) were compared:

[0044] 1) Fertilizer composition A1 prepared in Example 1, containing a stable suspension of Chevreul salt as the sole source of Cu,

[0045] 2) Fertilizer composition A5, containing water-soluble Cu 2+ A 5 wt% aqueous solution of a complex with EDTA as the sole source of Cu.

[0046] The concentration of Cu in both fertilizer compositions was the same (50 g / dm 3 Plants not treated with any fertilizer were used as controls. Application was carried out with a hand sprayer at a dosage of 2 l / ha at the growth stage of rapeseed at BBCH=16 (sixth complete leaf development).

[0047] Plant samples were collected on the 10th day after application of the fertilizer composition, and the aerial parts of the plants were thoroughly rinsed with 0.01% HCl to wash away any unabsorbed Cu. The weight of the dry matter of the aerial parts of the plants was determined, and the Cu content in the dry matter was determined using atomic absorption spectroscopy. The results of the analysis are summarized in Table 5.

[0048] Table 5: Copper content in dry matter of rapeseed

[0049]

[0050] The results show that foliar uptake of copper from both fertilizer compositions A1 and A5 was comparable, ie when the water-soluble copper compound was applied the plants received an amount of copper comparable to that received by the water-insoluble Chevreul salt applied in granular form.

[0051] Example 4

[0052] In this example, the effect of the fertilizer composition A4 prepared in Example 2 containing Chevreul salt as an active ingredient was tested on common wheat.

[0053] The experiment was conducted as a precise plant container experiment in a botanical pavilion. The model crop was common wheat (Triticum aestivum L.), variety Julia. Each type was replicated 6 times, with 15 plants per container. Each container contained soil with a weight of 1500 g / container. Soil properties are shown in Table 6. After sowing, uniform watering was ensured for all types throughout the growing period.

[0054] Table 6: Characteristics of soil used in the experiment

[0055] Soil parameters value <![CDATA[pH(CaCl2)]]> 6.09 <![CDATA[Carbon Oxidizable (C ox )]]> 0.80％ Clay 20％ Dust 27％ sand 53％ Cation exchange capacity 164mmol / kg N(total content) 0.19％ P (Mehlich 3 method) 36.4mg / kg K (Mehlich 3 method) 400mg / kg Ca (Mehlich 3 method) 2720mg / kg Mg (Mehlich 3 method) 214mg / kg

[0056] The fertilizer composition A4 containing the suspension formulation of the chevreul salt was applied to the plants. At the beginning of plant growth (at 2-3 leaves), the fertilizer composition was applied from the roots with a sprayer at a concentration of 2 l fertilizer / 250 l water (3 ml solution per container). Plants not applied with any fertilizer were used as controls.

[0057] The parameters monitored were measured weekly. After the experiment, the relative content of chlorophyll in the leaves of the plants was measured (expressed as the value given by the Yara N-Tester device), and the root capacitance corresponding to the root size of the plants was determined using an LCR multimeter ESCORT ELC-131D. Afterwards, the aerial parts of each plant were thoroughly rinsed with 0.01% HCl to wash away the unabsorbed nutrients. The weight and dry matter content of the aerial parts of the plants were determined, and standard inorganic analysis of the plants was performed (N content was determined by the Dumas method, P content was determined by absorptiometry, and Cu, K, Ca and Mg content was determined by atomic absorption spectroscopy).

[0058] The measurement results were evaluated by statistical methods (STATISTICA 12) using one-way ANOVA analysis followed by Fischer test (LSD test) at a significance level of 95% (p<0.05).

[0059] result:

[0060] A) Inorganic analysis

[0061] After applying the fertilizer composition A4 according to the invention, the Cu content in wheat increased significantly (p≤0.05), which was 7.1 times higher than the unfertilized type at the edge of Cu deficiency (Table 7). This result demonstrates the high efficiency of the fertilizer composition A4 as a Cu source for wheat. A slight increase in the nitrogen and potassium content in the plants was observed, which is a beneficial phenomenon. The content of other monitored nutrients was not significantly affected.

[0062] Table 7: Inorganic analysis results of wheat dry matter after application of fertilizer composition A4 relative to the control

[0063]

[0064] B) Plant weight and dry matter yield

[0065] Application of fertilizer composition A4 resulted in a significant increase in total dry matter yield and its content (p≤0.05) (Table 8). This result demonstrates the beneficial properties of Chevreul salt in the treatment of copper deficiency in wheat.

[0066] Table 8: Dry matter yield and content of wheat after application of fertilizer according to the present invention

[0067]

[0068] C) Chlorophyll content

[0069] Application of fertilizer composition A4 resulted in a significant increase (p≤0.05) in chlorophyll content, expressed as a relative value indicated by Yara N-Tester, by 16% (Table 9). The results indicate the positive effect of the fertilizers of the invention on plant metabolism and vitality.

[0070] Table 9: N-tester values ​​after application of fertilizers according to the invention

[0071] type N-Tester Value relatively% Comparison 511 100 Composition A4 593 116

[0072] D) The electrical capacity of the root system

[0073] The capacitance of the root system (expressed in nanofarads, nF) is a measure of the effective surface of the root system. Living plant tissue reacts to the passage of electric current as a capacitor (it can temporarily accumulate charge) and its parallel capacitance can be measured. In addition to the size of the active root system, it also corresponds to the membrane activity of the cells.

[0074] Application of the fertilizer composition A4 according to the invention resulted in a significant increase (p≤0.05) of 26% in the electrical capacity of the root system (Table 10). The results show that the fertilizers according to the invention have a positive effect on root growth and plant vigor.

[0075] Table 10: Root size measured by LCR meter after applying the fertilizer of the present invention

[0076] type Root capacitance (nF) relatively% Comparison 1.55 100 Composition A4 1.95 126

[0077] Example 5

[0078] The effect of the fertilizer composition A4 prepared in Example 2 and containing Chevreul salt as an active ingredient was tested on corn.

[0079] The experiment was a precision plant container experiment conducted under controlled temperature conditions in a greenhouse (day temperature 20°C / 12h, night temperature 10°C / 12h). The model crop was maize (Zea mays L.), variety SY Orpheus. Each type was replicated 6 times, 3 plants per container. Each container contained a soil weight of 1500 g / container, the soil having the same characteristics as shown in Table 6 of Example 4. After sowing, ensure uniform watering of all types throughout the plant growth period.

[0080] The fertilizer composition A4 (3 ml solution per container) was applied foliarly at the beginning of plant growth (at 2-3 leaves) with a sprayer at a concentration of 2 l fertilizer / 250 l water. Plants that were not treated with any fertilizer served as controls. After the experiment, the aerial parts of each plant were thoroughly rinsed with 0.01% HCl to wash off any unabsorbed nutrients. The weight and dry matter content of the aerial parts of the plants were determined, and standard inorganic analysis of the plants was performed similarly to Example 4. The statistical evaluation of the monitored parameters was performed similarly to the experiment shown in Example 4.

[0081] result:

[0082] A) Inorganic analysis

[0083] After applying fertilizer composition A4, the Cu content in corn increased significantly (p≤0.05), which was 5.5 times that of the unfertilized type (Table 11). This result shows that the fertilizer of the present invention is highly efficient as a Cu source for corn. The content of other monitored nutrients was not significantly affected.

[0084] Table 11: Inorganic analysis of corn dry matter after application of fertilizers according to the invention

[0085]

[0086] B) Plant weight and dry matter yield

[0087] Application of fertilizer composition A4 resulted in an increase in total yield and content of dry matter of corn (Table 12).

[0088] Table 12: Dry matter yield and content of corn after applying the fertilizer according to the present invention

[0089]

[0090] Example 6: Preparation of wettable powder and water-dispersible granule formulations (fertilizer compositions A6 and A7)

[0091] The Chevreul salts with a particle size of less than 2 μm and the excipients listed in Table 13 (the amounts correspond to the "Preparation" column) were mechanically mixed and homogenized. The resulting paste was spread into a thin layer on a drying pad and dried in a laboratory drying oven at 50° C. under an inert nitrogen atmosphere for 4 hours. After drying, the layer had the composition shown in Table 13 (column "After drying").

[0092] Table 13 Preparation and composition of fertilizers A6 and A7

[0093]

[0094] *Zephrym PD 3315 is a polymeric surfactant supplied as a 35 wt% solution.

[0095] The dried layer was transferred from the drying mat to laboratory sieves, which were stacked one on top of the other, with mesh sizes of 850 μm (20 mesh conforming to ASTM standard), 425 μm (40 mesh conforming to ASTM standard) and 150 μm (100 mesh conforming to ASTM standard). After sieving, two size fractions representing the two fertilizers were obtained, which were marked as A6-wettable powder (the fraction passing through the 100 mesh) and A7-granules dispersible in water (the fraction passing through the 40 mesh but not through the 100 mesh).

Claims

1. Use of Cu2SO3·CuSO3·2H2O as a fertilizer to provide copper to plants.

2. A method for providing plant nutrition, comprising the step of applying Cu2SO3·CuSO3·2H2O to seeds, plants, fruits or soil.

3. A fertilizer composition for fertilizing plants, characterized in that The invention comprises Cu2SO3.CuSO3.2H2O and at least one auxiliary substance selected from solvent, surfactant, rheology modifier, antioxidant and defoaming agent.

4. The fertilizer composition of claim 3, further comprising a source of at least one nutrient, wherein the nutrient is selected from the group consisting of: N, P, K, Ca, Mg, S, B, Cl, Fe, Mn, Mo, Ni and Zn.

5. The fertilizer composition of claim 4, wherein the source of the nutrient is selected from the group consisting of ammonium nitrate, potassium nitrate, calcium nitrate, calcium carbonate, magnesium carbonate, dolomitic limestone, urea, ammonium sulfate, calcium dihydrogen phosphate, calcium sulfate dihydrate, ammonium phosphate monohydrate, potassium chloride, potassium sulfate, kainite, magnesium sulfate, magnesium sulfate heptahydrate, magnesium sulfate monohydrate, ferrous sulfate, ferrous sulfate heptahydrate, Fe 3+ Complex with ethylenediaminetetraacetate, complex with boric acid and ethanolamine, manganese(II) chloride, manganese(II) chloride dihydrate, manganese(II) chloride tetrahydrate, manganese(II) sulfate, manganese(II) sulfate monohydrate, manganese(II) sulfate tetrahydrate, ammonium molybdate, sodium molybdate, nickel sulfate, nickel sulfate hexahydrate, nickel sulfate heptahydrate, zinc sulfate, Zn 2+ Complex with ethylenediaminetetraacetate, zinc sulfate hexahydrate, zinc sulfate heptahydrate.

6. A fertilizer composition according to any one of claims 3 to 5, which is in the form of a wettable powder or water-dispersible granules and comprises 10 to 95% by weight of Cu2SO3.CuSO3.2H2O.

7. A fertilizer composition according to any one of claims 3 to 5, in the form of a suspension concentrate and comprising 1 to 50 wt% Cu2SO3.CuSO3.2H2O.

8. The fertilizer composition according to any one of claims 3 to 7, wherein the particle size of Cu2SO3.CuSO3.2H2O is at most 40 μm, preferably at most 8 μm, more preferably at most 4 μm.

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