AU2006200467B2 - Micronutrient chelate fertilizer - Google Patents

Description

S&FRef: 730670

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Fatemeh Shahla Nazaran, of 160 Smart Street, Fairfield, New South Wales, 2165, Australia Mohammad Nazaran Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Micronutrient chelate fertilizer Associated Provisional Application Details: [33] Country:

AU

[31] Appl'n No(s): 2005900501 [32] Application Date: 04 Feb 2005 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c Micronutrient Chelate Fertilizer Technical Field The present invention relates to micronutrient chelate fertilizers and methods for making the same.

Background of the Invention Chelates comprising iron and a chelating agent such as EDTA or EDDHA are useful for increasing the availability of soluble iron to plants and have been widely used in fertilizer compositions. However, weak chelates such as EDTA or simple citric chelate are ineffective when used in alkaline soils (pH 7) because of the possibility of the lo chelated iron being released and immediately undergoing unwanted side reactions. This problem arises due to the instability of the chelate in alkaline conditions. Additionally, EDTA-based fertilizer compositions readily precipitate in soil, particularly in alkaline conditions and hence do not fully penetrate to the plant roots thereby reducing their effectiveness.

Moreover, such conventional iron chelate fertilizers have a limited shelf life due to the effect of light and humidity leading to disruption of the organic complex and the accumulation of inactive break down products; for example the active iron constituent is oxidised to Fe 3 There is therefore a need for an iron chelate composition that is capable of being used as a fertilizer in hard'alkaline soil conditions and that substantially ameliorates the above disadvantages of prior art fertilizers.

Summary of the Invention According to a first aspect of the present invention there is provided a micronutrient chelate fertilizer composition comprising an iron salt, sodium ions and a chelating agent wherein said chelating agent is an organic acid.

The organic acid may be a weak acid, or salt thereof, that is capable of forming a chelate, such as citric acid, tartaric acid, oxalic acid, a phenolic acid and mixtures thereof.

The iron salt may be an iron(II) salt. In one embodiment the iron salt is ferrous sulfate.

The sodium ions may be provided in the form of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium phosphate, sodium chloride, sodium sulfate, or any sodium salt.

In one embodiment the fertilizer composition further comprises a nitrogen source.

The nitrogen source may be urea or ammonium sulfate.

The fertilizer composition may have a pH between about 4 and about 8. In one embodiment the pH is neutral to alkaline, for example between about 6.5 and about 8, or between about 6.5 to about 7.5. Best results are obtained where the composition has a pH in the range of 6.5 to The fertilizer composition may further comprise one or more salts or oxides of at least one of the following elements: zinc, manganese, calcium, potassium, magnesium, molybdenum, boron, and copper.

The fertilizer composition may further comprise chloride, for example, sodium chloride, calcium chloride, potassium chloride.

1o The fertilizer composition may comprise water.

The zinc salt may be zinc sulfate, zinc phosphate or zinc oxide. Best results are obtained by using zinc sulfate.

The manganese salt may be manganese(II) sulfate or manganese(II) phosphate or manganese oxide. Best results are obtained by using manganese(II) sulfate.

The calcium salt may be calcium phosphate, calcium sulfate or calcium carbonate.

Best results are obtained by using calcium sulfate.

The potassium salt may be potassium sulfate or potassium carbonate. Best results are obtained by using potassium sulfate.

The fertilizer composition may further comprise a colouring agent. The colouring agent may be an iron(III) salt, such as an iron halide or iron(III) oxide. The fertilizer composition may further comprise phosphorous. The phosphorus may be present as phosphate.

The fertilizer composition may be in solid form, such as in the form of a powder, granules, pellets, tablets, wettable powder, or in a liquid form.

In one embodiment of the first aspect the fertilizer composition comprises: an iron salt; (ii) a nitrogen source; (iii) an organic acid that is not EDTA or EDDHA; (iv) sodium ions; a zinc salt; (vi) a manganese salt; and optionally: one or more salts or oxides of at least one of the following elements: calcium, potassium, magnesium, molybdenum, boron, and copper; (ii) water; and 3 (iii) a colouring agent.

The nitrogen source may be urea or ammonium sulfate.

The organic acid may be citric acid, oxalic acid, tartaric acid or a mixture thereof.

The fertilizer composition may further comprise chloride, for example, sodium chloride, calcium chloride, potassium chloride.

According to a second aspect of the present invention there is provided a micronutrient chelate fertilizer composition comprising: ferrous sulfate; (ii) sodium hydroxide or sodium chloride; 1o (iii) citric acid; (iv) urea.

The fertilizer composition may further comprise one or more oxides or salts of at least one of the following elements: zinc, manganese, calcium, potassium, magnesium, molybdenum, boron and copper.

The fertilizer composition may further comprise water.

The fertilizer composition may further comprise chloride.

The zinc salt may be zinc sulfate or zinc phosphate. The manganese salt may be manganese(II) sulfate or manganese(lI) phosphate. The calcium salt may be calcium phosphate or calcium sulfate. The potassium salt may be potassium sulfate or potassium carbonate.

The fertilizer composition may further comprise a colouring agent. The colouring agent may be an iron(III) salt, or an iron(III) oxide such as ferric oxide.

The fertilizer composition may further comprise phosphorous.

According to a third aspect of the present invention there is provided a micronutrient chelate fertilizer composition comprising: ferrous sulfate; (ii) urea; (ii) sodium hydroxide; (iv) citric acid; zinc sulfate; (vi) manganese sulfate; (vii) calcium phosphate; (viii) potassium sulfate; and (ix) ferric oxide; The fertilizer composition may further comprise one or more oxides or salts of at least one of the following elements: magnesium, molybdenum, boron and copper.

The fertilizer composition may further comprise water.

The fertilizer composition may further comprise chloride, for example, sodium chloride, calcium chloride, potassium chloride.

According to a fourth aspect of the present invention there is provided a method for supplying soluble iron to a plant, the method comprising applying to the plant or to the soil in which the plant is growing, an effective amount of a fertilizer composition of the first, second or third aspect.

1o According to a fifth aspect of the present invention there is provided a method for increasing the harvest of a crop from a plant, the method comprising applying to the plant or to the soil in which the plant is growing an effective amount of a fertilizer composition of the first, second or third aspect.

The crop may be any crop, edible or non-edible. The crop may be agricultural or Is horticultural. For example, the crop may comprise fruit, vegetable, grains, pulses, nuts, or flowers.

According to a sixth aspect the present invention there is provided a method for treating chlorosis or iron deficiency in a plant, the method comprising applying to the plant or to the soil in which the plant is growing an effective amount of a fertilizer composition of the first, second or third aspect.

According to a seventh aspect of the present invention there is provided the use of a fertilizer composition according to the first, second or third aspect for supplying soluble iron to a plant.

According to an eighth aspect of the present invention there is provided the use of a fertilizer composition according to the first, second or third aspect for increasing the harvest of a crop from a plant.

According to a ninth aspect of the present invention there is provided the use of a fertilizer composition according to the first, second or third aspect for treating chlorosis or iron deficiency in a plant.

According to a tenth aspect of the present invention there is provided a method of manufacturing a citric acid chelate said method comprising: mixing citric acid and at least one metal ion; (ii) heating the mixture obtained in step to a temperature of between about 100 'C and 140 OC; (iii) drying the mixture obtained in step (ii).

The at least one metal ion may be selected from the group consisting of: iron(II), zinc, manganese, calcium, potassium, magnesium, molybdenum, boron, copper and sodium.

Definitions In the context of the present specification, the term "chelate" is used to refer to a coordination compound derived from the complexing of metal ions with organic compounds resulting in the formation of a ring structure.

As used herein the term "effective amount" includes within its meaning a non-toxic but sufficient amount of a fertilizer composition to provide the desired effect. The exact amount required will vary depending on factors such as the species of plant to which the fertilizer composition is to be applied, the general condition of the plant, the particular fertilizer composition being administered, the soil, general ecological, and climatic environment in which the plant is growing, the mode of application, the season in which the fertilizer composition is applied and so forth. Thus, it is not possible to specify an exact "effective amount". However, for any given case, an appropriate "effective amount" may be determined by one of ordinary skill in the art using only routine experimentation.

In the context of this specification "increase" and "increasing" and other variations thereof as used in relation to crop harvests mean an improvement or increase in comparison to other plants either untreated or treated with a different fertilizer or growth medium and/or comparison to the average harvest prior to treatment with a fertilizer composition of the present invention or an otherwise defined basal level of harvest.

As used herein the term "treating" refers to any and all uses which remedy chlorosis or iron deficiency, prevent the establishment thereof, or otherwise prevent, hinder, retard, or reverse the progression of chlorosis or iron deficiency in any way whatsoever.

In the context of this specification, the term "comprising" means "including principally, but not necessarily solely". Furthermore, variations of the word "comprising", such as "comprise" and "comprises", have correspondingly varied meanings.

Brief Description of the Drawings Embodiments of the present invention will now be described, by way of example only, with reference to the following drawing: Figure 1. Flowchart of an exemplary production scheme for the production of an iron chelate fertilizer according to an embodiment of the present invention.

Best Mode of Performing the Invention Bivalent iron (Fe 2 is the most readily absorbed form of iron by plants for direct use in growth. As described herein the present invention relates to a novel micronutrient fertilizer composition for providing Fe 2 and optionally other chelated metal ions such as zinc, and optionally other micronutrients, to plants in hard alkaline soil conditions, thereby improving plant growth and increasing the quality and quantity of crops produced by plants.

Plants to which fertilizer compositions of the present invention may be applied include all plant varieties. The plants may produce agricultural or horticultural crops and edible or non-edible crops. Such crops include, for example, fruit, vegetables, grains, pulses, nuts and flowers. Fertilizer compositions of the present invention are applicable to plants grown in any suitable growth medium, typically soil or hydroponic solution.

The present invention provides fertilizer compositions that are non-toxic and which do not require large amounts of potentially environmentally damaging heavy metals such as molybdenum and copper. Fertilizer compositions of the present invention have the added benefit that they do not alter the existing soil structure or texture.

Fertilizer compositions of the present invention are also non-hormonal. Many prior art micronutrient fertilizers and plant growth supplements contain hormones. These boost plant growth when the fertilizer is first added and improve the appearance of plants, but have little or no effect on the quality of plant products. Hormone use promotes rapid growth however does not enable plants to obtain sufficient nutrients for crop production, and thus crops tend to suffer at least in terms of quality. Further there is growing concern over the potential effects of such hormone-containing fertilizers and growth supplements on animal health and development and particular the possibility that they may contribute to human diseases. As a result many individuals now prefer to use organic products free of hormone treatment.

In addition to the above, and as exemplified herein, the use of fertilizer compositions according to embodiments of the present invention result in increased quality and quantity of crops, promote natural early fruit production and ripening, prevent premature loss of fruit, prevent frost damage and prevent pest and parasite infestation and/or damage.

Fertilizer compositions of the invention According to one aspect the present invention provides a micronutrient chelate fertilizer composition comprising an iron salt, sodium ions and a weak acid that is capable of forming a chelate compound. Typically the iron salt is ferrous sulfate and the organic acid is selected from citric acid, oxalic acid, tartaric acid, phenolic acids or a mixture thereof.

Fertilizer compositions of the present invention provide the advantage of being capable of providing soluble chelated metals in a wide range of pH values from about 3 to about 11. For example, up to 30% soluble iron can be delivered to plants when the fertilizer composition is added to soils or growth media with a pH range of 3 to 11. Other iron chelates, for example plain citric acid .chelate and iron EDTA are not capable of efficiently supplying iron to plants where the soil/growth medium has a pH of greater io than about In embodiments of the present invention citric acid acts as a weak chelating agent, and ferrous sulfate as the provider of divalent iron. In the presence of sodium ions, citric acid and ferrous ions form a strong complex which is able to form chelates with other metal ions. The complex formed has a strong chelating affinity for micronutrient metals.

Theoretically it is possible to chelate a higher percentage of a desired metal compared to other metals present. It is well known that the importance of iron to plants is greater than other micronutrients.

The ratio of citric acid to ferrous sulfate in the complex affects the percentage of soluble iron (bivalent iron Fe2+ as measured in pH between about 3 and about 11). For optimal results, the w/w citric acid: ferrous sulfate ratio should remain within 50 to 100 percent.

Typically the sodium ions are provided in the form of sodium hydroxide sodium bicarbonate, sodium carbonate or sodium phosphate. Using sodium hydroxide rather than sodium bicarbonate assists in maintaining a neutral pH of the fertilizer. This is of particular importance if the fertilizer is to be added directly to soil. Additionally, the presence of sodium per se in the fertilizer composition plays some role as a micronutrient for plants.

A further aspect provides a micronutrient chelate fertilizer composition comprising: ferrous sulfate; (ii) sodium hydroxide; (iii) citric acid ;and (iv) a nitrogen source.

Nitrogen may be present in the form of ammonium sulfate, or more typically urea.

The nitrogen combined with other elements of the complex in the fertilizer composition helps to stabilize the soil nitrogen and assists in increasing the growth rate of plants.

A further aspect provides a micronutrient fertilizer composition comprising: ferrous sulfate; (ii) urea; (iii) sodium hydroxide; (iv) citric acid; zinc sulfate; (vi) manganese sulfate; (vii) calcium phosphate; (viii) potassium sulfate; 1o (ix) ferric oxide; and optionally phosphorous.

Although omitting elements such as zinc, manganese, calcium, potassium, copper, molybdenum, magnesium, boron, and ferric oxide does not alter the ability of a fertilizer composition according to the present invention to achieve the desired results, their is inclusion may increase the nutritional value of the fertilizer to plants. For example, the presence of chelated zinc and manganese interacting with urea in the complex may provide additional benefits to plants in terms of growth and harvest. Ferric oxide acts principally as a colouring agent, but it also acts as a source of iron (III) in the solution.

The sulfur content of fertilizer compositions according to embodiments of the present invention, for example as provided by virtue of one or more sulfates as outlined above, is of benefit for localized acidification of alkaline soils and also for the prevention or control of various pest and parasite infestations of plants. As exemplified herein, the application of a 1/1000 solution of a fertilizer composition according to the present invention on the leaves and fruit of olive, pistachio and rice resulted in the prevention of infestation by the common parasite "olive fly", protected at least 90% of pistachio crops against fungal (aflatoxin) attack and prevented infestation of rice crops by stem borers.

Fertilizer compositions according to the present invention provide stable complexed bivalent iron, not readily oxidized, and thereby inactivated, by, for example, light and/or humidity. As a result, fertilizer compositions of the present invention have an improved shelf life and display increased stability when compared to prior art iron chelate fertilizers in which the iron complex rapidly breaks down and the bivalent iron is oxidized when exposed to light or humidity for even a few days.

A fertilizer composition of the present invention may comprise constituents in the relative amounts indicated: water; about (ii) iron sulfate; about 32% (iii) urea; about 3% (iv) citric acid; about 26% ferric oxide; about 2% (vi) sodium hydroxide; about 19% (vii) zinc sulfate; and about 4% (viii) manganese sulfate, about 4%.

In one embodiment the composition further comprises about 2% calcium phosphate and/or about 2% potassium sulfate.

Those skilled in the art will readily appreciate that the above relative amounts may be altered or varied depending on circumstances or intended application of the fertilizer and these approximate relative amounts are in no way intended to limit the scope of the is present invention. By way of example, the amount of each of the above listed constituents may be varied by approximately Application The amount of a micronutrient fertilizer according to the invention that may be applied to plants or soils in order to achieve the desired effect will typically be determined on a case by case basis taking into consideration a number of factors, for example, the plant type to be treated, plant size, the condition of the plant(s) to be treated, the season, time to harvest, climatic conditions in the local environment, ecology of the local environment, the geographical environment, soil type and soil characteristics. Soil characteristics may include pH (acidity/alkalinity), soil structure, salinity, organic constituents. One skilled in the art will be able to determine the appropriate application rate for a fertilizer of the invention depending on the relevant factors such as those detailed above.

By way of example, Table 1 below sets out suitable application rates for a variety of agricultural crops and horticultural plants.

Table 1- Typical application rates for a variety of crops/plants Crop/plant type Examples Application rate Fruit trees apple, pear, cherry, peach, 80 160 g per tree in full (stone or seed) apricot, nectarine, almond, plum, productivity' walnut, hazelnut, fig, date, quince, pomegranate, persimmon, olive Citrus and non orange, tangerine, mandarin, 100 200 g per tree in full fruit bearing large lemon productivity 2 trees Grapes 20 25 kg per hectare 3 Pistachios 50 100 g per tree in full productivity 4 Summer crops melons watermelon, 5 10 kg per hectare cantaloupe), cucumber, tomato, egg plant Potatoes and onions 10 15 kg per hectare Row crop vegetables cabbage, lettuce, celery, sweet 3 5 kg per hectare basil, cress Strawberries 20 30 kg per hectare Sugar beet 20 25 kg per hectare Field crops grains, corn, wheat, barley, 3 10 kg per hectare alfalfa, rice Maize 20 25 kg per hectare Oily seeds crops Cotton, soya, sunflower 10 -15 kg per hectare Flowers roses etc. 40 50 kg per hectare 6 Lawn and pot 20 25 kg per hectare 7 flowers 1 2 3 4 5 6 7 40-80 g per young tree 50 100 g per young tree 15 20 g per tree 20 50 g per young tree At least 2 g per m 2 2 10 g per vase 2 5 g per m 2 Those skilled in the art will readily appreciate that the above application rates are merely guidelines suitable for the application of fertilizer compositions according to the present invention and are based on plants in a generally healthy state. A higher application rate may be used for plants in poor condition. For example a higher application rate may be warranted for plants exhibiting signs of iron deficiency, such as yellowing foliage. In such instances the application rate may be increased by about 5% to about 50%, by about 10% to about 30%, or by about 15% to about 25%. Those skilled in the art will also appreciate that the above amounts may be administered in a single io application or preferably may be administered over more than one application at different times.

A fertilizer according to an embodiment of the present invention may be applied during the growth period at any time throughout the year. Typically, to achieve maximal benefit, a fertilizer according to an embodiment of the present invention will be applied at the beginning of the growth season for established plants and crops or soon after the emergence of new plants. However the fertilizer may be beneficially applied up until shortly prior to harvest. In one embodiment the application of the fertilizer may be performed intermittently, or at regular intervals throughout the growing period.

Further, those skilled in the art will appreciate that fertilizers in accordance with the present invention may be applied in conjunction with, prior to or following other treatments or nutritional supplements, such as other fertilizers. For example a fertilizer of the present invention may be applied following the application of an NPK (nitrogen:phosphorous:potassium) supplement.

The number of applications of fertilizer required to achieve the desired results will depend on a variety of factors including, for example, the plant type to be treated, plant size, the condition of the plant(s) to be treated, the season, time to harvest, climatic conditions in the local environment, ecology of the local environment, the geographical environment, soil type and soil characteristics. Typically, for application directly to the soil the fertilizer may be applied two or more times during the growing season.

The micronutrient fertilizer of the present invention may be produced either in solid or liquid form. The solid form may comprise, for example, powder, granules pellets, tablets or a wettable powder. A larger granule or pellet size is more convenient when slow release of nutrients is desired, e.g. when the composition is applied to trees.

Similarly, a fertilizer of the present invention may be applied either in solid or liquid form. Solid forms of fertilizer may be first dissolved in a suitable amount of water to 12 produce a solution for application either to the soil or foliage of the plants. As exemplified herein a 1:1000 solution, comprising I g of fertilizer per litre of water may be used.

Fertilizers of the present invention in solid form are typically administered directly to the soil, while liquid forms may be applied either to the soil or to the foliage of the plants. Application to foliage may comprise preparing a dilute solution of fertilizer (for example 1 g fertilizer in 1 litre of water) and applying via a spray system. Application directly to the soil typically has the advantage of enabling the most efficient uptake of nutrients by the plants via their root systems. For example fertilizer of the present 1o invention in solid form may be spread directly onto the soil and/or may be mixed with topsoil prior to being watered in. Alternatively, in solid form or in solution, the fertilizer may be applied by pouring under a thin layer of soil before watering. Alternatively, fertilizers of the present invention may be applied via an existing irrigation system, for example in large scale farming operations. Fertilizers of the present invention dissolve in water more slowly than prior art iron chelate fertilizers thereby producing a regular supply of nutrients to the plants over a longer period of time.

Production One exemplary process for producing a solid form of fertilizer composition according to the present invention is illustrated schematically in Figure 1.

In the first combining step 110, typically at a batching plant, each of the constituents of the fertilizer is combined. All constituents may be combined simultaneously or in any desired order provided, where applicable, the sodium compound (for example sodium hydroxide, sodium bicarbonate or sodium phosphate) is added last.

The addition of the sodium compound initiates a heat producing reaction. Typically the addition of the sodium compound is performed in the presence of a fan or other exhaust means to remove fumes produced.

Typically water is added in the combining step 110, for example 3000 kg water for a 10000 kg net weight fertilizer, to provide a liquid environment for the mixing and dissolving of the remaining constituents.

The constituents are blended in a mixing step 120. Mixing typically continues for a period of time sufficient to ensure all constituents are appropriately mixed and a liquid form produced. In one embodiment mixing may proceed for approximately 1 hour.

During the mixing step 120 the temperature of the composition typically rises, for example up to at least 100 0 C, due to the exothermic nature of the reactions taking place.

13 In experiments conducted by the inventor the temperature of the composition has been raised to approximately 120'C without adverse effect on the production of the final fertilizer composition. In fact, it has been found that keeping the temperature in the range of 100-140 C for a period of up to 30 minutes will maximize the percentage of available soluble metals in the micronutrient fertilizer ultimately produced. Some precipitated materials may be present in the mixing output, mainly due to impurities of used materials, added colours, or inaccurate measurement of mixed materials. These precipitates may be removed by filtering or centrifugation. In an alternative embodiment all of the constituents are added to water, with the exception of sodium hydroxide which is added 1o following addition of all of the other constituents. In another embodiment all of the constituents are mixed together, with sodium hydroxide being added last. In this embodiment no water is added meaning that drying step 130 is significantly shorter. The pH of the composition may be controlled by the addition of a base such as sodium hydroxide and/or sodium bicarbonate.

Following mixing and heating 120, the liquid composition is then dried 130. By way of example the drying 130 may comprise oven drying, raising the temperature of the composition and stirring or using other suitable drying means. For oven drying, any suitable oven may be used, for example a microwave oven. For temperature and stirring the temperature may be raised, for example, to at least 50 0 C. Other suitable drying means may include, for example, a spray drying device. The particular drying means to be utilised may depend, for example, on the water content of the composition prior to drying and the batch size of the fertilizer composition being produced. The water content of the fertilizer composition need not be reduced to 0% in the drying step, but typically will be substantially reduced. For example, a water content of approximately 2% in the dried composition may be acceptable.

Following drying 130, the dried form of the fertilizer composition is then processed and packaged 140. Processing may comprise grinding, or granulating and/or sieving of the composition to obtain the desired particle or granule size of the fertilizer.

Examples The invention will now be described in more detail by way of illustration only, with respect to the following examples. The examples are intended to serve to illustrate the invention and should not be construed as limiting the generality of the disclosure of the description throughout the specification.

Example 1: Typical fertilizer compositions A typical fertilizer composition in accordance with an embodiment of the present invention comprises the following components: water; 300 g (ii) iron sulfate; 1000 g (iii) urea; 100 g (iv) citric acid; 800 g ferric oxide; 50 g (vi) sodium hydroxide; 600 g lo (vii) zinc sulfate; and 130 g (viii) manganese sulfate. 130 g Another typical fertilizer composition in accordance with an embodiment of the present invention comprises the following components: water; 300 g (ii) iron sulfate; 1000 g (iii) urea; 100 g (iv) citric acid; 800 g ferric oxide; 50 g (vi) sodium hydroxide; 600 g (vii) zinc sulfate; and 130 g (viii) manganese sulfate. 130 g (ix) calcium phosphate 50 g potassium sulfate 50 g Example 2: Effects of fertilizer compositions A micronutrient fertilizer according to an embodiment of the present invention was administered to various agricultural and horticultural crops to determine the effect of the fertilizer on growth and yield in a range of species in different soil and climatic conditions.

Apple tree 160g of fertilizer granules was added to soil around an individual apple tree in Mashad, Iran. Prior to the present trial this tree typically bore approximately 20kg of fruit per year and had been fertilized with a commercial (Sequestrene 138) iron fertilizer for 4 years prior to the present trial without any significant result. Several months following treatment with the present fertilizer the tree produced approximately 1000kg of healthy and tasty apples.

Apple orchard 27g of fertilizer was applied to each tree as a solution to part of a 53 acre apple orchard in Damavand, Iran through irrigation drips. The treated part yielded at least more fruit compared to the untreated part and also compared to previous years. The apples ripened one month early in the treated part of the orchard and it was observed that the fruit were more flavoursome (sweeter and tastier).

o Wheat kg of fertilizer was dissolved in water used for irrigation of a 7000m 2 wheat farm in Khoramdareh, Iran. The fertilizer reduced the time to harvest, resulted in heavier and more complete wheat clusters than in previous years, and resulted in a 20% increase in wheat production compared to the previous year. The average protein content of grains was 40% more than those of control grains (from untreated wheat).

Citrus A 1/1000 solution of fertilizer (Ig fertilizer in IL water) was applied in a single application to a 100 acre citrus orchard (containing oranges, mandarins and grapefruits) in Saadabad, Jiroft, Iran. The following harvest yielded about 50% more fruit than in previous years. The fruit was sweeter, the oranges ripened one month earlier, fruit loss was reduced, and the fruit more homogenous in size and quality. It was also observed that the trees had significantly greener and fresher leaves than prior to treatment.

Date 250g of fertilizer was added directly to the soil around each tree in a 50 acre palm orchard. A 200% increase in yield resulted. Dates were almost double the size of those previously produced and fruit loss was reduced to Rice of fertilizer per acre was applied to a rice paddy in Foumanat, Iran. There was a 50% increase in harvest weight, and no sign of stem borers. Clustering was more complete and milling resulted in less broken grains (around 70% less).

Melons of fertilizer per acre was mixed with irrigation water for an uncultivated land (which was covered by salt deposits) in Varamin, Iran to grow rockmelons. 40% more rockmelons than expected from a similar size melon patch were harvested.

Strawberries 16 of fertilizer per acre was applied to a strawberry farm in Hashtgerd, Iran.

Plants yielded 50% more strawberries than prior to treatment and were observed to have a superior taste.

Pomegranate 100g of fertilizer was applied to a pomegranate tree in Tehran, Iran. Prior to treatment the tree had produced small, dry fruits. Following the addition of the fertilizer numerous large, juicy fruits were produced.

Pistachio nuts A 2 acre pistachio orchard in Rafsanjan, Iran was foliage sprinkled once with a 0o 1/1000 solution of fertilzer. Harvested product increased by at least 50% compared to prior to fertilizer treatment. Control (untreated) plants produced on average 32 pistachios per ounce, compared to 26 pistachios per ounce from fertilizer treated plants. Individual nut size and quantity was increased by fertilizer treatment. Contamination of crops with Aflatoxin (Aspergillus flavus) decreased by 90%, which in turn saves the cost and environmental hazards of using fungicides. It was also observed that the number of buds (for the following years harvest) had also increased and leaves were larger and greener.

Claims (19)

1. A micronutrient chelate fertilizer comprising: an iron salt, a nitrogen source, an organic acid that is not EDTA or EDDHA, sodium ions, a zinc salt and a manganese salt, and optionally: one or more salts or oxides of at least one of the elements selected from the group consisting of: calcium, potassium, magnesium, molybdenum, boron, and copper; (ii) water; and (iii) a colouring agent.

2. The fertilizer composition of claim 1, wherein the iron salt is ferrous sulfate.

3. The fertilizer composition of claim 1 or claim 2, wherein the nitrogen source is urea or ammonium sulfate.

4. The fertilizer composition of any one of claims 1 to 3, wherein the organic acid is citric acid, oxalic acid, tartaric acid or a mixture thereof.

5. A micronutrient chelate fertilizer composition comprising: ferrous sulfate, sodium hydroxide or sodium chloride, citric acid, and urea.

6. The fertilizer composition of claim 5, wherein said composition further comprises one or more salts or oxides of at least one of the elements selected from the group consisting of: zinc, manganese, calcium, potassium, magnesium, molybdenum, boron, and copper.

7. The fertilizer composition of claim 5 or claim 6, further comprising a colouring agent.

8. The fertilizer composition of claim 6 or claim 7, wherein the zinc salt is zinc sulfate.

9. The fertilizer composition of any one of claims 6 to 8, wherein the manganese salt is manganese(II) sulfate.

The fertilizer composition of any one of claims 6 to 9, wherein the calcium salt is calcium sulfate or calcium phosphate.

11. The fertilizer composition of any one of claims 6 to 10, wherein the potassium salt is potassium sulfate.

12. The fertilizer composition of any one of claims 7 to 11, wherein the colouring agent is ferric oxide.

13. The fertilizer composition of claim 12 capable of providing soluble chelated metals in a range of pH values from about 3 to about 11.

14. The fertilizer composition of any one of claims 1 to 13, further comprising chloride.

A method for supplying soluble iron to a plant, the method comprising applying to the plant or to the soil in which the plant is growing, an effective amount of a fertilizer composition of any one of claims 1 to 14.

16. A method for increasing the harvest of a crop from a plant, the method comprising applying to the plant or to the soil in which the plant is growing, an effective amount of a fertilizer composition of any one of claims 1 to 14.

17. A method for treating chlorosis or iron deficiency in a plant, the method comprising applying to the plant or to the soil in which the plant is growing, an effective amount of a fertilizer composition of any one of claims 1 to 14.

18. Use of a fertilizer composition according to any one of claims 1 to 14, for supplying soluble iron to a plant, increasing the harvest of a crop from a plant, or treating chlorosis or iron deficiency in a plant.

19. A method of manufacturing a citric acid chelate said method comprising: mixing citric acid and at least one metal ion; (ii) heating the mixture obtained in step to a temperature of between about 100°C and 140'C for up to 30 minutes; and (iii) drying the mixture obtained in step (ii), wherein the at least one metal ion is selected from the group consisting of: iron zinc, manganese, calcium, potassium, magnesium, molybdenum, boron, copper, and sodium. A fertilizer composition substantially as hereinbefore described with reference to Example 1. Dated 23 January, 2009 Fatemeh Shahla Nazaran Patent Attorneys for the Applicant/Nominated Person 1o SPRUSON FERGUSON