AU784288B2 - Biological fertiliser composition - Google Patents

Description

P/01/009 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT We certify that the following Eighteen (18) pages are a true and correct copy of the description and claims of the original complete specification in respect of an invention entitled BIOLOGICAL FERTILISER COMPOSITION Name of Applicant: Signature THE ERA FARMING COMPANY PTY LTD Richard H. Baddeley Registered Patent Attorney BIOLOGICAL FERTILISER COMPOSITION This invention relates to biological fertiliser compositions and methods for their production and use. Such compositions contain important nutrient elements and compounds for employment in soil fertilisation. In such manner, plant growth and development may be promoted.

At the present time, most fertilisers in conventional use are chemical fertilisers, not natural products. For example, as US 5912398 explains, phosphorus fertilisers are produced by chemical treatment of mined phosphate ores. The chemical conversion of mineral phosphate ore into phosphate fertiliser is an energy intensive process involving high temperature leaching of phosphate ore. The leaching process generates contaminants and the resultant fertilisers are often over-utilised.

As an alternative to such chemical fertilisers have been proposed biological fertilisers which are naturally occurring materials or derived from naturally occurring materials. For example, a biological source of phosphorus is rock phosphate. A problem with rock phosphate is its environmental insolubility in soils. Thus it has been proposed to increase the efficacy of rock phosphate by inoculating the rock with phosphate solubilising bacteria: "Rock Phosphate for o Ecological Farming", The Hindu, 7 June, 1995.

As that article points out, crops grown using such inoculated phosphate rock have shown extensive root development and better tolerance to biotic and abiotic stresses. Indeed, the avoidance of such stresses is at the core of biological fertilisation methods.

A more complex composition is disclosed in US Patent No. 5912398. That 25 composition furnishes continuous release of soluble phosphate into soil for uptake by plants. The composition, added to soil, includes a microorganism capable of producing and releasing a solubilisation agent for solubilising insoluble phosphate and a source of phosphate, preferably rock phosphate ore after application. The solubilised phosphate would then be available to plants when the composition is applied to crop growing areas. The composition further includes a carbon source for microorganism growth.

The composition is formulated into a physical form in which the various components are adjacent to each other to promote phosphate solubilisation.

Solubilised phosphate is then released into the plant growing environment.

A granular physical form is preferred. The so granulated composition can then be broadcast over the crop growing area.

Such a composition is concerned only with the application of phosphate to crop growing areas. The nutrient needs of crops are somewhat more complex.

Therefore, it is necessary to develop fertiliser compositions which have a broader range of nutrient supply capability. Specifically, the fertiliser composition would preferably have NPK analysis. Other nutrient elements may also be desirable.

US Patent No. 4563207 discloses a clay breaking and fertilising composition and a method for its use. The fertilising composition includes an intimate mixture of calcium carbonate, basic phosphate, a water-soluble potash (potassium) compound and dried protein-rich manure in such proportions that when spread on clay soil and watered, the composition has a clay-breaking and *fertilising effect.

15 The preferred manure is chicken manure and phosphate rock may be used S as the source of phosphate.

c As far as may be understood, this reference proposes no microbial digestion of the mixture prior to application to an area to be fertilised. Further, leaching may be a problem with such a fertiliser composition.

20 It is the object of the present invention to provide a fertiliser composition that is straightforward to make and use while avoiding problems such as those discussed above.

;"!With this object in view, the present invention provides a biologically acceptable fertilizing composition derived by at least partial microbial digestion prior to application of said composition to an area to be fertilized, the composition including the following components fertilizing components adjusted in proportion to give the desired NPK analysis; a source of phosphate, preferably rock phosphate; an adsorbent material; biomass derived from a microbial inoculate; a carbon source suitable to sustain growth of digestion microorganisms; and a potassium source.

By "biologically acceptable" is meant a fertilising component(s) which occurs naturally in the environment or fertilising component(s) derived from such naturally occurring materials without chemical processing. Such materials can be distinguished from those chemical fertilisers requiring conventional chemical processing of naturally occurring materials for their production, for example, the superphosphate fertilisers.

The various components of the digestion mixture may, where appropriate or applicable, be added in liquid or solid form.

The digestion mixture may further include trace metal additives such as copper, zinc, manganese and molybdenum compounds. Non metallic additives may include boron compounds. A calcium supplement, such as lime or gypsum, may also be added to the mixture if calcium levels in the soil to be fertilised are insufficient.

The mixture may incorporate food enzymes to promote enzymatic action on the digestion mixture. Such enzymes may be derived from fish material.

Vitamins may also be included. For example, thiamine, biotin, vitamin B 12 pantothenic acid, folic acid, nicotinic acid and/or riboflavin as well as other 15 vitamins may be added to the digestion mixture or produced during digestion.

As to suitable nitrogen additives, advantageously to be added, there may especially be mentioned urea (with high nitrogen analysis) as well as plant or animal derived nitrogenous fertiliser compositions whether in liquid or solid form.

S Suitable sources of nitrogen may include liquid fish emulsions, liquid chicken or other animal nutrients. These fertilisers provide a preferred amine form of o nitrogen derived from proteins and amino acids.

Manures and other animal waste products may be incorporated within the o digestion mixture. Cattle and poultry manures are especially suitable. Poultry manure, especially chicken manure, may advantageously be used.

25 A suitable potassium source, is potassium sulphate, potassium carbonate o or blends thereof. Other biologically acceptable sources of potassium may also be used. The utilisation of potassium sulphate, in particular, has beneficial effects in solubilising phosphorus being an acidic compound in solution. The mild chemical reaction enhances the effects of the organic acids being produced by inoculated microorganisms.

As indicated above, the mixture includes a natural source of phosphate. A suitable source is phosphate rock which may be derived from phosphate mining operations around the world. There are phosphate rock deposits in Australia and overseas.

In another embodiment, the fertilizing composition of the present invention further includes an organic compound containing at least one carboxyl group or carboxylate salt such as acetate, citrate or oxalate. Such compounds have a strong affinity to phosphorus..

In another aspect, the organic compound may be oxalate, citrate, acetate or other like carboxylic compound, included within a non-biologically acceptable or chemical fertilizer to enhance release of insoluble phosphorus from the soil.

The organic compound, may, for example, be citrate salts such as alkali metal citrates; or oxalate salts, such as sodium oxalate or ammonium oxalate; or oxalic acid, or citric acid, or mixtures thereof.

It has been found by the Applicant that inclusion of an oxalate source such as ammonium oxalate or sodium oxalate may be beneficial because of its 15 capacity to release phosphorus from soil in an chemical reaction. Ammonium oxalate may be preferred. Other oxalates and compounds including at least one carboxylic group, other it is thought than calcium oxalate (being insoluble), may be used. It is also possible that other leaching agents for phosphate may be useful. The oxalate compound may be derived from Bayer alumina process waste including sodium oxalate. Calcium oxalate formed in Bayer processing may also be reacted with ammonia/carbon dioxide to form ammonium oxalate.

In any event, further optimization of phosphorus release may be achieved by addition of oxalate or compounds including at least one carboxylic group.

Sodium oxalate solution solubilises small amounts (expected to be, 19% by 25 weight phosphate rock) of otherwise potentially plant unavailable phosphorus from soil in such a reaction. Up to 1 kg phosphorus may be released per 2 kg oxalate applied to soil. Without wishing to be bound by any theory, it is believed that chemical reaction involves the exchange of a dicarboxylic group for a calcium or ferrous or ferric ion (or any other ion which can form a chemical bond with phosphorus), then forming calcium oxalate, ferrous oxalate, ferric oxalate or the like.

The sodium ion can then attach itself to available hydroxyl or phosphate ions leaving the phosphorus ion available for plant uptake. In particular, phosphorus availability may be enhanced around root zone of plants, especially when combined with applied phosphorus in the form, for example, of phosphate rock.

The utilisation of organic acids (oxalic, citric, acetic) in fertiliser compounds improves the availability of the phosphorus by reducing fixation through the process of chelation. The metal ions are bonded to the organic acids preventing them from locking up in the soil but are still available to the plants. This process applies to the utilisation of chemical fertilizers as well as slow release fertilizers.

The chelation process is a natural process of keeping phosphate available to plants as soil organisms convert sugars into various organic acids and then excrete them into the soil solution as a by-product of metabolism.

Such an effect may be particularly useful in the early growth stage of plants where a substantial portion of their phosphorus requirements (up to is taken up. This early growth stage is about six weeks in duration. It appears 15 that an alkaline reaction, such as induced by the oxalate ion, may improve the plant availability of other nutrients present in soil surrounding the root zone also.

Lime application, which also promotes alkaline reaction, may be associated with improved nutrient availability but may be less beneficial than sodium oxalate in phosphate release from soil.

Without wishing to be limited by any theory, it is believed that the same chemical reactions occur within the soil when oxalate, citrate or carboxyl containing compounds, such as carboxylate salts of alkali metals, are combined with chemical fertilizers or biological fertilizers and applied to the soil.

It will be understood from the above description that a further inventive :00: 25 aspect provides a method for producing a fertiliser in which a fertiliser component, S• as described above, is admixed with alumina process waste containing a carboxylate salt, as above described, preferably a salt of an alkali metal or ammonium.

A method of fertilizing soils including application to a soil of such a fertilizing composition is also provided in a still further aspect.

An adsorbent material such as a suitable clay for example, smectite clay, zeolite clay, montmorillonite, bentonite, saponite, illite, kaolinite or otherwise; or activated carbon may be added to the digestion mixture from the commencement 6 of digestion. As well as providing a support for microorganisms and liberated nutrients, such additives may be useful in odour control. Clays and activated carbon prevent nutrient leaching tendency. Activated carbon controls odour and is moisture retentive. Activated carbon may also increase plant availability of nitrogen. Other filler materials such as rock fines, rock dusts, sand or other remineralisation agents, to re-mineralise depleted soils, may be included in the digestion mixture. Rock additives such as igneous rock additives may remineralise over-farmed soils.

As the carbon source for microorganisms may particularly be mentioned carbohydrates. Polysaccharides, or complex carbohydrates, such as glucose, fructose, galactose, sucrose or other may advantageously be employed. Further, polymers and copolymers of glucose, for example starch, may also be used as a carbon source. The carbon source may be in liquid, solution, or solid form.

Molasses from sugar production may be a suitable source.

15 As carbon source with fertilising capacity may again be mentioned manures, as described above. Other carbonaceous wastes could be used also.

l9** Heat treatment of manures and wastes is not contemplated.

l The quantity of carbon source introduced to the mixture may be calculated in accordance with the degree of biomass, a measure of microbial population, that it is desired to attain during digestion.

Whilst digesting microorganisms, particularly phosphate solubilising organisms, need not be inoculated into the digestion mixture, with the fee.

:0 microorganisms present in the mixture then performing the digestion, it may be more preferable for such microorganisms to be introduced to the mixture.

25 As described above, phosphate rock contains normally insoluble phosphate. Therefore, it may be desirable to inoculate the digestion mixtures with suitable phosphate solubilising microorganisms. Bacteria, other fungi and actinomycetes may also play a role.

US Patent No. 5912398 provides a useful disclosure of suitable microorganisms. Quoting directly, of particular interest are bacteria exhibiting the mineral phosphate solubilising trait as well as fungi and actinomycetes that exhibit the ability to solubilise rock phosphate ore and other biological sources of insoluble phosphate. Suitable microorganisms, perhaps preferably to be used, may be selected from the genera Erwinia, Pseudomonas, Gluconobacter, Klebsiella, Acinetobacter, Aspergillus, Penicillium, Paecilomyces, Acremonium, Verticillium, Geomyces, Chrysosporium, and mixtures thereof.

More preferred microorganisms include Pseudomonas cepacia, Aspergillus niger, Aspergillus phenicis, Peniccillium herquei, Penicillium funiculosum, Penicillium lanoso-coerulum, Penicillium simlicissum, Penicillium atramentosum, Penicillium roquefortii, Paecilomyces sp, Acremonium sp, Verticillium sp, Geomyces sp, Chrysosporium sp and mixed cultures thereof.

Strains of these named microorganisms that have been selected or mutated to have enhanced rock phosphate solubilising properties may be used.

Other microorganisms that exhibit the same functionality may also be used.

Thiobacillus spp, which is a sulphur oxidising microorganism, may be employed. This organism oxidises sulphur forming sulphuric acid in the presence of water. Sulphuric acid may act as phosphate solubilising agent. Elemental 15 sulphur or pyrite may be added to the mixture as an energy source to promote this effect.

.However, US Patent No. 5912398 does not disclose inclusion of agriculturally active microbes other than those mentioned above. In accordance with the present invention, nitrogen fixing microorganisms such as Derxia, Azotobacter and Beijerinckia or other agriculturally active microorganisms may be introduced to an inoculating culture. In particular, it is desirable that the digestion produce humic and fulvic acids which are important to soil nutrition. These products of microbial digestion may be produced in greater yield by particular microorganisms. Humic and fulvic acids, generated during digestion, may 25 function as chelating agents which can release nutrients making them plant available and preventing them both from leaching and locking-up in the soil.

Microorganisms that promote formation of humic and fulvic acids may be introduced to digestion.

In another inventive aspect, the invention provides a process for manufacturing a fertilizing composition of any one of the preceding claims, including the steps of mixing the following components, fertilizing components adjusted in proportion to give the desired NPK analysis; a source of phosphate; an adsorbent material; a microbial inoculate; a 8 carbon source suitable to sustain growth of digestion microorganisms together; and a potassium source and holding the mixture for a predetermined digestion time.

It may be necessary to adjust the moisture content of the digestion mixture to promote digestion. No limit is set on moisture content though it is anticipated that moisture content shall not exceed about 10% by weight of the total digestion mixture. An anticipated range is 5 to 10% by weight.

Moisture control might be done in dependence on digestion mixture temperature. Accordingly, if temperature exceeds a permissible level, suggesting excessive microbial activity, say about 600C, water may be introduced to the mixture. Sprinklers attached to a water supply may distribute water over the digestion mixture. Small additions of water are contemplated. When digestion temperature falls to an acceptable level again, water introduction may be stopped.

15 It is anticipated that the digestion process may be conducted in simple drum type vessels. Other types of digester may be used. Digestion time may ",vary but the expected time range may reach several weeks, about two to three weeks being the expected time but up to 4 weeks being possible. Preferred e digestion temperature range is 25°C to 350C.

The product of digestion may be granulated or pelletised. Product pellets or granules may be 2-5mm (not more than 10mm in diameter) in diameter and S" may be applied to an area to be fertilised by broadcasting or other conventional methods of fertiliser application.

•co -Fertiliser compositions in accordance with the various aspects of the 25 present invention may be applied to soil to provide nutrients which significantly reduce the energy load on growing plants. This reduced energy requirement increases crop growth and yield.

Further, the composition allows use of waste products, such as molasses, from the sugar industry, in a biologically acceptable way. The resulting composition does not leach significantly, allows increases in nutrient availability and crop growth, as well as moisture holding capacity. Importantly humic and fulvic acid addition to soil in the product composition also has benefits in improving nutrient availability and crop growth.

9 The present invention may be more fully understood from the following Example which shows only one illustrative fertiliser composition falling within the scope of the present invention. The Example is not intended to be limiting.

Example A blend of the following components was prepared, adding each component to the digester, a drum of suitable volume. The digestion is aerobic initially but becomes aerobic in the later stages. On a 100kg basis, a blend was prepared as follows.

Milled phosphate rock (P 2 0 5 analysis 24% by weight) Potassium Sulphate 18 Solid N fertiliser Manure Source (chicken manure) Activated carbon 7 TOTAL MASS SOLIDS: Mass Liquid Component (kg~ Polysaccharide (molasses) Vitamin B12 0.01 Food enzyme 0.005 Microbial Inoculate trace Water TOTAL MASS LIQUID: Total Mass Composition 100 The milled phosphate rock may be used in accordance with the characterisation of US Patent No. 5912398. That is, the phosphate rock may grade 24% in particles that pass through a 200 mesh screen. Other NPK fertilisers may be added in any desired proportions, all fertilisers being biologically acceptable.

Any commercially available source of activated carbon may be used.

Further, the balance of activated carbon may be proportioned between clay and activated carbons as desired. A clay, such as a bentonite or montmorillonite clay, may less advantageously take the place of activated carbon. A filler such as sand, or finely divided mineral material including igneous rock dust may be included.

Activated carbon, clay and/or filler may be added, in whole or part, after commencement of the digestion process.

The microbial inoculant may comprise a culture of Acinetobacter calcoaceticus and Gluconobacter oxydans as described in US Patent No.

5912398. Other microorganisms could be employed instead.

The mixture was then allowed to digest for 14 days. The digestion time may vary but may reach 4 weeks.

Where necessary during the digestion, water may be introduced to reduce the temperature from 600C to a more acceptable temperature range, say about S to 35 0

C.

The sources of NPK are added to maintain a desired analysis of one or more of these above about However, if necessary, NPK content may be •varied by addition of further fertiliser components, before, during or after 20 digestion. It can clearly be seen that an NPK analysis above 5% of each is achieved in accordance with the above example.

The digested product may be pelletised or granulated. A disc pelletiser or extruder may be used for this purpose. Potassium sulphate may be added in liquid form acting as a binder for granulating or pelletising the product. The fertiliser may then be applied to areas to be fertilised by conventional techniques.

Such a fertiliser may be a slow release fertiliser.

o Experiments have also been conducted to assess the effect of oxalate inclusion on phosphorus release, Sodium oxalate, in particular, as sourced from Bayer alumina process waste was tested. Indicative experiments showed that up to 70% phosphorus release from soil as plant available phosphorus might be attained through oxalate reaction with otherwise plant unavailable phosphorus. A "slow release" effect may be achieved. About 20-100kg oxalate addition per hectare is anticipated addition range.

11 Root zone availability of phosphorus is thus enhanced. Plants may not utilise all released phosphorus but increased phosphorus availability during the six weeks following application, may be particularly beneficial to plant growth.

Conventional phosphatic fertilisers are not expected to be useful for maintaining such substantial phosphorus levels due to leaching or adsorption (into plant unavailable form) effects.

Modifications and variations to the fertiliser composition of the present invention may be made by the skilled reader of this disclosure. Such modifications and variations fall within the scope of the present invention. In particular, the proportions of NPK components may be varied as desired. In addition, the nature of the NPK components may be varied as desired subject to biological acceptability being maintained. Liquid or solid fertiliser compositions may be used.

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Claims (31)

1. A biologically acceptable fertilizing composition derived by at least partial microbial digestion prior to application of said composition to an area to be fertilized, the composition including the following components: a) fertilizing components adjusted in proportion to give the desired NPK analysis; b) phosphate rock; c) an adsorbent material; d) biomass derived from a microbial inoculate; and e) a carbon source suitable to sustain growth of digestion microorganisms; and f) a potassium source.

2. A fertilizing composition of claim 1, wherein said components of said composition are in a solid or liquid form.

3. A fertilizing composition of claim 1 or 2, further including trace metal additives.

4. A fertilizing composition of any one of the preceding claims, further ooooo including a calcium supplement. S 5. A fertilizing composition of any one of the preceding claims, further including food enzymes.

6. A fertilizing composition of any one of the preceding claims, further including the addition of vitamins.

7. A fertilizing composition of any one of the preceding claims wherein the potassium source is potassium sulphate. 13

8. A fertilizing composition of any one of the preceding claims, further including an organic compound containing at least one carboxylic group or a salt thereof.

9. A fertilizing composition as claimed in claim 8, wherein said compound is selected from the group consisting of citrate and oxalate salts. A fertilizing composition as claimed in claim 8 or 9, wherein said oxalate salt is sodium oxalate or ammonium oxalate.

11. A fertilizing composition as claimed in claim 9 or 10, wherein said oxalate compound is derived from alumina processing waste (red mud).

12. A fertilizing composition of any one of the preceding claims wherein said adsorbent material is clay or activated carbon.

13. A fertilizing composition of any one of the preceding claims wherein the fertilizing components are manures or other animal waste.

14. A fertilizing composition of any one of the preceding claims wherein said carbon source suitable to sustain growth of microorganisms is a carbohydrate selected from the group consisting of polysaccharides, glucose, fructose, galactose, sucrose and mixtures thereof. A fertilizing composition of any one of the preceding claims microbial inoculate includes sulphur oxidizing microorganisms.

16. A fertilizing composition of any one of the preceding claims microbial inoculate includes phosphate solubilizing microorganisms.

17. A fertilizing composition of any one of the preceding claims microbial inoculate includes nitrogen fixing microorganisms. wherein the wherein the wherein the 14

18. A fertilizing composition of any one of the preceding claims wherein the microbial inoculate includes microorganisms that form humic and fulvic acids during digestion of the fertilizing composition.

19. A process for manufacturing a fertilizing composition of any one of the preceding claims, including the steps of: mixing the following components a) fertilizing components adjusted in proportion to give the desired NPK analysis; b) phosphate rock; 0 c) an adsorbent material; microc d) a microbial inoculate; e) a carbon source suitable to sustain growth of digestion )rganisms together; and f) a potassium source; and holding the mixture for a predetermined digestion time.

20. A process as claimed in claim 19, wherein the quantity of carbon source introduced to said composition is calculated as a function of the degree of biomass to be achieved during digestion.

21. A process of claim 19 or 20, wherein the fertilizing composition is held for digestion for a period between 14 days and 4 weeks.

22. A process of any one of claims 19, 20 and 21, wherein the temperature of the fertilizing composition is held between 250C and 350C.

23. A process of any one of claims 19 to 22, wherein the temperature is held at the desired temperature by the addition of water.

24. A process of any one of claims 19 to 23, wherein the moisture content does not exceed 10% by weight. process of any one of claims 19 to 23, wherein the moisture content is between 5% and 10% by weight.

26. A process as claimed in any one of claims 19 to 25, wherein alumina processing waste is mixed with said remaining components during manufacture of said fertiliser composition.

27. A product of the process of claims 19 to 26, manufactured into pellets or granules.

28. A product of claim 27, wherein the pellets and granules are less than in diameter.

29. A product of claim 27, wherein the pellets and granules are between 2- in diameter.

30. A process for producing a fertiliser in which the fertilizing composition of any one of claims 1 to 18 is admixed with Bayer alumina processing waste containing a carboxylate salt.

31. A process of claim 30, wherein said carboxylate salt is a salt of an alkali metal or ammonium.

32. A process of claim 30 or 31, wherein said carboxylate salt is an oxalate, citrate or acetate.

33. A process of claim 32 wherein said carboxylate salt is sodium oxalate or ammonium oxalate.

34. The product of the process of any one of claims 19 to 33. A method of fertilizing soils comprising application to a soil of a fertilizing composition as claimed in any one of claims 1 to 18. 16

36. A method of fertilizing soils comprising application to a soil of a product as claimed in any one of claims 27 to 30 or 29. DATED this 13 th day of December 2005 THE ERA FARMING COMPANY PTY LTD WATERMARK PATENT TRADE MARK ATTORNEYS GPO BOX 2512 PERTH WA 6001 AUSTRALIA P16824AU00 o