AU2013207561B2 - Fertiliser formulation - Google Patents

Abstract

The invention provides a stable, water soluble fertiliser suspension comprising water, at least one nutrient, and a stabiliser, wherein the stabiliser is guano. 5 Included in the invention is a fertiliser suspension that has a surprisingly high concentration of nutrients, and a method of making the suspension.

Description

FERTILISER FORMULATION FIELD OF THE INVENTION

The invention described herein relates to fertiliser formulations. In particular, the invention is directed to stable liquid fertiliser formulations and stable high potassium liquid fertiliser formulations.

BACKGROUND ART

Plants generally require a nutritionally balanced soluble nutrient feed program for healthy and rapid growth. Many mineral fertilisers comprising mineral salts have limited solubility in water. This has implications for the cost of production and application, as suspensions for application to crops have to be made up on site, and solutions are necessarily dilute.

Settling out of suspended material is problematic for manufacture, transport and application as the actives are lost as solids, and cause problems with the mechanism of pumping and spraying.

Various attempts have been made to address the problem of limited solubility of fertiliser mixtures. Some of the attempts at a solution are disclosed in U.S. Patent Nos. 3,519,413 and 3,950,159, where a suspension of coarse particles and a hydrophilic or a polysaccharide gum for thickening is disclosed. U.S. Patent No. 4,069,034 describes a method of making a suspension fertiliser with bentonite and humic acid as crystal growth modifiers. This disclosure is directed to a manufacturing process that deals with supersaturating nitrogen and phosphorous in a reactor at elevated temperatures. U.S. Patent No. 4,525,197 discloses a fertiliser suspension that utilizes magnesium-aluminium silicate as a stabilizer along with a dispersant selected from sorbitol, polyvinyl alcohol, caseinate, and soluble starch hydrolosates to prevent the formation of large crystals.

Another known technique is to use a co-solvent that is miscible with the solvent that lowers the solubility of the mineral salt and slows the rate of crystal growth. The limitation of this option is that few co-solvents are non-toxic to plant growth.

Currently in Australia farmers are forced to mix dry fertiliser with water to dissolution or suspension on site. This is expensive, time-consuming, laborious and water-intensive.

Available suspensions are expensive as the solids have to be micronized to about 70microns to ensure suspension, and this adds to the expense of manufacture.

In particular, fertilisers for banana crops are very high in potassium, with w/w20-30% potassium. As potassium is particularly difficult to solubilise, this exacerbates the problem of a liquid formulation.

Therefore, there would be an advantage if it were possible to provide a concentrated, stable, water soluble fertiliser suspension which may overcome at least some of the above-mentioned disadvantages or provide a useful or commercial choice.

SUMMARY OF THE INVENTION

In a first aspect, the invention resides in a stable, water soluble fertiliser suspension comprising water, at least one nutrient, and a stabiliser, wherein the stabiliser is guano.

In a second aspect, the invention resides in a stable, water soluble fertiliser suspension comprising water, at least one nutrient, and a stabiliser, wherein the stabiliser is guano and the concentration of the stable suspension is from 55% w/w to 75%w/w.

In a third aspect, the invention resides in a method of manufacturing a stable, water soluble fertiliser suspension, the method comprising the steps of: • Adding water to a mixer; • Adding at least one fertiliser nutrient to the water; • Mixing xanthum gum and oil separately; • Adding the xanthum gum and oil mixture to the mixer; • Adding stabiliser to the mixer, wherein the stabiliser is guano; • Mixing the resultant stabilised suspension and decanting the suspension.

In a fourth aspect, the invention resides in a stable, water soluble fertiliser suspension made by the method of the third aspect. 'Stable’ in the context of the present invention means that suspended material does not settle out of suspension for at least 6 to 8 weeks.

With regard to the first, second and third aspects above, the at least one nutrient can be any nutrient or mixture of nutrients required for an effective fertiliser. The nutrients can include, but are not limited to, one or a combination of any of K2S04, KCI, KOH, K2C03, KNO3, Urea, urea-ammonium nitrate, potassium phosphate, ammonium phosphate, calcium phosphate, MgS04, MgN03, zinc, copper, boron, iron, manganese, silica dioxide, humic acid, kelp, and fish elusion.

The amount of each of the nutrients can be any practicable amount, singly or in combination with one or more nutrients, but is preferably in the percentages w/w final product as follows: l<2SO4(20-85%), KCI( 10-40%), KOH(1-5%), K2C03{1-5%), KN03(10-30%), Urea(10-30%), urea-ammonium nitrate( 10-30%), ammonium su!phate(1-5%), potassium phosphate(1-10%), ammonium phosphate(1-10%), calcium phosphate(1-10%), MgSO4(1-10%), MgNO3(1-10%), zinc(1-3%), copper(0.5-2%), boron(1-2%), iron(1-2%), manganese(1-2%), silica dioxide(1-20%), humic acid(1-10%), kelp(0.5-1%), and fish elusion(0.5-10%).

More preferably, and particularly for fertilisers for banana plants, the concentration of potassium sulphate (K2SO4) is greater that 30% w/w. This is a higher concentration than has been achieved before the present invention and is highly advantageous to plants using liquid fertilisers.

The quality of the at least one nutrient of the suspension of the invention can be any grade suitable for a fertiliser. The at least one nutrient can be used as provided by the supplier (technical grade) or can be milled or micronized. Advantageously, the present invention allows for use of unprocessed, technical grade nutrient/s to be used in the suspension of the invention, without the need for processing or milling before addition to the suspension of the invention.

The guano can be any guano, but is preferably avian guano. The guano can be added to the at least one nutrient in any amount sufficient to give a stable suspension of the invention. Preferably the guano is added in an amount from 0.5% to 10% w/w final product. More preferably, the guano is added in an amount of about 2% w/w final product.

The guano is preferably micronized to between 1 and 50 microns before addition to the at least one nutrient and water. More preferably, the guano is micronized to about 5 microns before addition to the at least one nutrient and water.

The suspension of the invention can optionally include other inert components. For example, the suspension can include xanthum gum as a suspension agent, canola oil as an emulsifier, and/or fulvic acid for nutrient retention in the soil. Preferably, these components are present in the amounts as follows (w/w): fulvic acid(1-5%), xanthum gum(0.1-1%), canola oil(0.1-1%).

With regard to the third aspect of the invention, the oil can be any practicable oil, but is preferably canola oil, or oils simitar to canola oil.

The suspension of the invention is stable for up to eight weeks from manufacture.

The stable suspension of the invention can then be provided to the farmer as a liquid fertiliser. The farmer can easily add the suspension to an irrigation system, where the suspension is solubilised in the abundance of water of the irrigation system.

The advantages of the stable suspension of the invention are numerous. The suspension is economical to produce, easy to provide to the farmer and less labour intensive for the farmer to apply than existing systems. The suspension of the invention aiso allows for more frequent applications of nutrients in smaller quantities, which in turn results in more efficient uptake of the nutrients. Use of the suspension of the invention results in fewer run-offs, and an overall improvement in quality and quantity of crop to which the suspension is applied.

In order that the invention may be more readily understood and put into practice, one or more preferred embodiments thereof will now be described.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Having broadly described the invention above, non-limiting examples of the suspension of the invention and their preparation, will now be given.

Example 1: General Method of Preparation

In general, the fertiliser suspension of the invention is prepared as follows. Water (about 30% of the mass of final product) is added to a mixer. Raw materials as listed in Examples 2 and 3 are added to the water in the order indicated. The xanthum gum and canola oil are mixed separately prior to addition to the water. The suspension is mixed to the desired pH and viscosity, and then decanted for transport.

Example 2: A First Formulation of the Suspension of the Invention

The general method described in Example 1 is followed, using the constituents below, to give a first suspension of the invention.

Raw Material Raw Material (kg) End product (kg)

Water 480 480 HPX (polysaccharide) 9 489

Zinc sulphate 12 501

Copper sulphate 4 505

Urea-ammonium nitrate 265 770

Monoammonium phosphate 50 820

Magnesium sulphate 50 870

Potassium sulphate 575 1445

Potassium hydroxide 28 1473

Guano 12 1485

Xanthum gum 3,5 1488.5

Canola oil 5 1493.5

Fuivic acid 8 1501.5

Total Weight of Product 1501.5

Specific gravity 1.5015

Example 3: A Second Formulation of the Suspension of the Invention

The general method described in Example 1 is followed, using the constituents below, to give a second suspension of the invention.

Raw Material Raw Material (kg) End product (kg)

Water 510 510

Monoammonium phosphate 120 630

Boron 12.5 642.5

Monoammonium phosphate 50 692.5

Potassium sulphate 470 1162.5

Potassium hydroxide 7 1169.5

Urea-ammonium nitrate 240 1409.5

Guano 12 1421.5

Xanthum gum 3.5 1425

Canola oil 5 1430

Total Weight of Product 1430

Specific gravity 1.43

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the present invention without departing from the spirit or scope of the invention as broadly described. The above examples are therefore to be considered in all respects illustrative and not restrictive.

The term “comprise” and variants of the term such as “comprises” or “comprising” are used herein to denote the inclusion of a stated integer or stated integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive interpretation of the term is required.

Any reference to publications cited in this specification is not an admission that the disclosures constitute common general knowledge in Australia.

Claims (20)

1. A stable, water soluble fertiliser suspension comprising: water; at least one nutrient; and between 0.5% w/w and 10% w/w of a stabiliser; wherein the stabiliser is micronized guano having a size between 1 and 50 micron.

2. The suspension of claim 1 wherein the nutrient is selected from the group consisting of K2S04, KCI, KOH, K2CO3, KNO3, Urea, urea-ammonium nitrate, ammonium sulphate, potassium phosphate, ammonium phosphate, calcium phosphate, MgS04, MgN03, zinc, copper, boron, iron, manganese, silica dioxide, humic acid, kelp, and fish elusion.

3. The fertiliser suspension of claim 1 or claim 2 wherein the at least one nutrient is a combination of two or more nutrients.

4. The fertiliser suspension of any one of claims 1 to 3 wherein the nutrient is of technical grade.

5. The fertiliser suspension of any one of claims 1 to 4 wherein the guano is avian guano.

6. The fertiliser suspension of any one of claims 1 to 5 wherein the guano is from 0.5 to 10% w/w of the suspension.

7. The fertiliser suspension of any one of claims 1 to 6 wherein the guano has a size of about 5 microns.

8. The fertiliser suspension of any one of claims 1 to 7, further comprising one or more components selected from the group consisting of xanthan gum, fulvic acid and canola oil.

9. The fertiliser suspension of claim 8 including potassium sulphate, wherein the concentration of the potassium sulphate is at least 30% w/w.

10. The fertiliser suspension of claim 1 wherein the concentration of the suspension is from 55% w/w to 75%w/w.

11. A stable, water soluble fertiliser suspension comprising water, at least one nutrient, and between 0.5% w/w and 10% w/w of a stabiliser, wherein the stabiliser is micronized guano having a size between 1 and 50 micron and the concentration of the stable suspension is from 55% w/w to 75%w/w.

12. The suspension of claim 11 wherein the nutrient is selected from the group consisting of K2S04, KCI, KOH, K2C03, KNO3, Urea, urea-ammonium nitrate, ammonium sulphate, potassium phosphate, ammonium phosphate, calcium phosphate, MgS04, MgN03, zinc, copper, boron, iron, manganese, silica dioxide, humic acid, fulvic acid, kelp, and fish elusion.

13. The fertiliser suspension of claim 11 wherein the at least one nutrient is a combination of two or more nutrients.

14. The fertiliser suspension of any one of claims 11 to 13 wherein the guano is avian guano.

15. The fertiliser suspension of any one of claims 11 to 14 wherein the guano is from 0.5 to 10% w/w of the suspension.

16. The fertiliser suspension of any one of claims 11 to 15 wherein the guano has a size of about 5 microns.

17. The fertiliser suspension of any one of claims 11 to 16, further comprising one or more components selected from the group consisting of xanthan gum, fulvic acid and canola oil.

18. A method of manufacturing a stable, water soluble fertiliser suspension, the method comprising the steps of: • Adding water to a mixer; • Adding at least one fertiliser nutrient to the water; • Mixing xanthum gum and oil separately; • Adding the xanthum gum and oil mixture to the mixer; • Adding between 0.5% w/w and 10% w/w of stabiliser to the mixer, wherein the stabiliser is micronized guano having a size between 1 and 50 micron; • Mixing the resultant stabilised suspension and decanting the suspension.

19. The method of claim 18 wherein the least one fertiliser nutrient includes potassium sulphate and the concentration of the potassium sulphate is at least 30% w/w.

20. A stable, water soluble fertiliser suspension made by the method of claim 18 or claim 19.