NZ241079A - Fertilizers - mineral and nutrient mix for rapid establishment of microbial flora - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £41 079 Z. PATENT OFFICE 19 MAR 1993 PATENTS FORM NO. 5 Fee No. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 241079 Dated: 19 December 1991 /ED £ IMPROVEMENTS IN AND RELATING TO COMPOSITIONS i (> u c. 1 ic>° 1 COMPRISING A BINDER AND NUTRIENT . IL_tCl'i Ac,It L H-"IHC/A L WE MOANA FERTILISERS LIMITED a New Zealand company of Baldhill Road, RD 1, Waiuku, New Zealand hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 c*fxL\J J ;This invention relates to improvements in and relating to compositions comprising a binder and nutrient. ;Technical Field ;This invention is directed towards fertilisers. More specifically, many embodiments are directed to providing a nutrient suitable for the rapid establishment of fungus or micro-organisms on a suitable mineral substrate. In many instances the mineral substrate will comprise a rock phosphate or other substantially insoluble phosphate product, however other materials may also be; used. ;The nutrient is typically chosen to allow for the rapid establishment of fungus in other micro-organisms which are present in the soil, and in particular those which aid in phosphate solubilisation may be specifically targeted. ;Background Art ;Phosphorus, one of the main trace elements, is generally added to pasture in the form of superphosphate, an acidified form of rock phosphate. Compared with normal rock phosphate, which is generally and predominantly calcium phosphate, superphosphate is much more soluble and is released to be available to plants relatively quickly. ;Rock phosphate is still used in the fertiliser industry for application to pasture, particularly where the more rapid release of the superphosphate is not required, or where a long term slow release of plant phosphorus may be preferred. Economics also comes into play as rock phosphate needs only to be milled whereas superphosphate requires, in addition, treatment of the raw phosphate material with acid. Over a large acreage, ;2 ;W1019 ;cost differences can become significant. During lean times many farmers may be faced with a choice of spreading superphosphate, cheaper rock phosphate (which may not be suitable for the particular application) or not fertilising with a phosphorus containing material at 5 all. Furthermore, the acidic nature of superphosphate often requires liming if the normal soil pH is to be maintained. ;A growing trend towards the use of naturally occurring fertilisers is also occurring. There are relatively few natural fertilisers, with the possible exception of fish based compositions, which are high in phosphorus. 10 However these may over supply other elements in addressing a phosphorus deficiency. Rock phosphate also considered to be a naturally occuring fertiliser however, lacks the faster release characteristics of superphosphate and is often not suitable as a direct replacement. ;There are many micro-organisms and fungi, many of which occur 15 naturally in soils, which are advantageous to have in pasture as enhancing or encouraging plant growth. Some of these assist the plant in taking nutrients from the soil while many others are able to assist the release of nutrients, otherwise bound up, to be available to plant life. While research continues, many are now well known. Encouraging the 20 growth of these organisms may often be advantageous, especially those associated with the solubilisation of phosphate minerals. ;It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. ;Further aspects and advantages of the present invention will become 25 apparent from the ensuing description which is given by way of example only. ;3 ;Disclosure of invention ;According to one aspect of the present invention there is provided a fertiliser composition comprising: ;- a mineral substrate, and ;- an introduced nutrient source for rapidly establishing fungal or microbial growth. ;According to another aspect of the present invention there is provided a fertiliser composition substantially as described above in which said introduced nutrient includes an ammonium compound, or an amine. ;According to another aspect of the present invention there is provided a fertiliser composition substantially as described above in which said mineral substrate includes at least one member of a group comprising: aluminosilicate (as herein defined), lime, zeolite, clay, and phosphate minerals. ;According to another aspect of the present invention there is provided a fertiliser composition substantially as described above in which said particles of the composition have been coated with a nutrient support. ;According to another aspect of the present invention there is provided a fertiliser composition substantially as described above in which the introduced nutrient or nutrient support has been adapted for the rapid establishment of a member of the group consisting of: a member of the genus Aspergillus, a member of the genus Penicillium, a member of the genus Cylindrocladium, a member of the genus Pseudomonas, and a member of the species Fitsarium oxysporum, Fusarium solani, ;4 ;Aspergillus niger, Aspergillus candidus, Aspergillus flavus, Aspergillus ustus, Penicillium janthinellum, Sclerotium rolfsii, and Bacillus megatherium phospaticums. ;According to another aspect of the present invention there is provided a method for the production of a fertiliser composition comprising the introduction of a nutrient source for rapidly establishing fungal or microbial growth, to a mineral substrate. ;According to another aspect of the present invention there is provided a method substantially as described above in which a nutrient support is coated onto, and/or allowed to impregnate into, the surface of particles of the mineral substrate. ;Embodiments of the present invention will comprise a mineral substrate. The mineral substrate serves to act as a base for introduced nutrients which will serve to accelerate the establishment of biologically active material (i.e. fungus, micro-organism (including microbes) and/or reproductive material therefor) present in the soil or pasture etc. As typically the action of the more desired biologically active material is to improve phosphate solubilisation and release into the soil, the mineral substrate will normally comprise a phosphate material. While virtually any phosphate material may be used, it will typically comprise an insoluble phosphate, as compared to more soluble forms such as 'super phosphate'. A good example of the insoluble phosphates include the so-called rock phosphates, some specific examples of which are the North Carolina rock phosphates (NCRP), Peruvian rock phosphates (available in New Zealand under the name SECURAROCK ™), or the Egyptian rock ;/ • i ; j ' J • ■*> — ^ phosphates (marketed in New Zealand under the name QUINPHOS™). However, it should be appreciated that other forms of rock, and insoluble, phosphates exist which may be used within the present invention, though it is considered that phosphate materials commercially exploited for 5 fertiliser application will usually be employed. It is also envisaged that phosphate materials present in the mineral substrate need not be restricted to the generally less expensive insoluble forms.

The mineral substrate may comprise solely one or more rock or insoluble phosphates. However in other embodiments, additional constituents may 10 be present. These may be present as discrete particles in a composition or incorporated into more sophisticated 'pellet' type forms, to be discussed as follows.

Typically the mineral substrate will comprise a solid granule or pellet through may also substantially comprise a powdered material. In most 15 cases the average particle size will not exceed 10mm as larger material is not readily spread by most commercial equipment and large fragments may be a hindrance to farming. As, to some extent, nutrient and mineral release (per weight of binding material) is dependent upon particle size (powdered forms generally having a faster release), particle size can be 20 used to help govern the release characteristics of the product.

The substrate may comprise many materials though will often be substantially mineral in nature. The substrate may comprise solely naturally occurring materials, such as rock phosphate, broken where necessary to an appropriate size. Alternatively, it may comprise a 25 reconstituted conglomerate or pellet of, substantially, minerals. For example it could comprise powdered rock phosphate pressed into a pellet 6 form of a uniform size.

By way of example, additional constituents may comprise an aluminosilicate, which term wherever used herein shall often refer to an aluminosilicate clay. There are many such materials known and include, by way of example only, vermiculite, bentonite (montmorillonite), sepiolite-attapulgite, illite, chlorite, halloysite and kaolinite.

One preferred aluminosilicate for use in the present invention is bentonite which is readily available. Bentonite generally refers to a clay comprising more than 70% montmorillonite.

If the process allows, it may be desirable to incorporate other components into the pellet. This may be, for example, lime, clays, zeolites or various minerals. These may act as nutrients for the inicro-organisms or fungi, or comprise plant available nutrients to be eventually released to a plant. The other components may modify the physical characteristics of the pellet, such as by helping cement the pellet together, or adjusting the porosity (which can affect how well a pellet may be impregnated or how quickly it 'releases' its contents after application).

Where substantially non-processed materials, such as straight insoluble phosphate, is used, the available options may be limited. However, there is room for great variation in the nature of a product if one or more constituents are broken down and re-combined to form the mineral substrate. As can be appreciated, attributes such as the porosity, fertiliser content, particle size and other variables can be rigidly controlled and almost infinitely varied. However it will also be appreciated that this will increase the number of manufacturing steps and thus, the cost of the end product. It shall be assumed that a reader ^ M O J skilled in the art will be able to select components suitable for their needs and combine them into a suitable pellet. Similarly the manufacture of bound or pressed pellets is well known and the many possible techniques will not be described herein.

Another constituent which may be included in a fertiliser composition, and which may be present as part of the mineral substrate or added subsequently, is a hydrating agent. Some non-reversable hydrating agents have been mentioned already and these include unslaked limes, calcium sulphate, gypsum and other cementing type constituents. These 10 may be included to help cement particles or granules together, or to absorb excess moisture such as from a liquid nutrient (if added). The effect in this case will be to absorb the added moisture so that the end product is still a substantially dry, flowable material.

Other hydrating agents are known and these may not necessarily be 15 predominantly binding or cementing type materials. For instance, calcium chloride and various silica gels are among other well known hydrating agents (the term 'hydrating agent' or 'hydrating constituent' being used to indicate a substance capable of absorbing or adsorbing moisture). Zeolite materials may also be used as hydrating agents.

Also of use are what shall be termed as reversible hydrating agents, in which water taken in is available for use by the biologically active material introduced from the soil. Useful in this regard are many gels such as gelatine and agars though many more are also known. One fish based fertiliser, suitable for use as a nutrient in the present invention, 25 includes seaweed whose proportion can be varied during manufacture to alter the viscosity of the resulting product. This product is available in 8 ^ i J Australasia from Moana Fertilisers Limited of Waiuku, New Zealand under the trade mark MOANA™.

Another substance of use are the newer cross-linked polymers, some of which are biodegradable (usually after a period of several years). Some of 5 these have been recently put to use in potting mixes and the applicant is aware of at least one product available in Australia under the trade name of AGROSOKE™.

Hydrating agents and constituents may be employed in the present invention, not only to absorb excess moisture so that a substantially dry 10 product results, or to act as a cementable binder in some cases, but also to accelerate the establishment of soil present biological organisms. Many will find a moisture rich support conducive to growth. Some zeolites and aluminosilicates may be useful in this regard.

Embodiments of the present invention will also include a nutrient. 15 Typically this will be a nutrient useful to targeted biologically active material. Typically these will also be plant useful nutrients and thus a dual purpose may be provided - there is a nutrient suitable for sustaining soil present biological material, and secondly, the NPKS characteristics of the fertiliser may be altered which can extend the range of applicability 20 for the end product as a fertiliser.

A nutrient may comprise materials commonly used as plant fertilisers and the invention represents an alternative means of preparing a high phosphorus, multi-elemental fertiliser. Often these 'normal fertilisers' will also enhance the growth of targeted fungi and micro-organisms. In 25 most cases a nutrient acting as a nitrogen source is sufficient but should not be in such a high or readily available concentration as to adversely 9 2 u / J affect any targeted organisms.

While many nitrogen providing nutrient sources may be used, some preferred embodiments of the present invention make use of nutrients containing ammonium compounds or amines. Many ammonium and 5 amine based fertilisers are known and may be employed. However, it is noted that many fish based fertilisers are also rich in amines and, depending on the production of process, a typical ammoniacal smell can often be detected. Typically the use of ammonium, and amine containing, nutrients will be beneficial as recent research by others have suggested 10 that the nitrification of free ammonia can increase the solubility of North Carolina phosphate rock (NCPR). This research (published in Compost Science and Utilisation. Premier Issue, 1993) supports the applicant's observation that the use of a fish based fertiliser product on phosphate rock noticeably increased its solubility and, therefore, availability for 15 plants. In some instances a significant ammoniacal smell was detected after fungal growth had been established. The use of nutrients able to be readily converted into free ammonia for subsequent nitrification processes may be especially useful in some embodiments, and may be a means by which the rate of release of phosphorous from the insoluble 20 phosphate can be varied.

The aforementioned fish based fertiliser product, based on the acid and base hydrolysis of marine matter, has been found to be effective in trials. Granular mineral substrate impregnated with the fish fertiliser was found to support the growth of fungal and plant matter after a relatively 25 short period though this will depend upon a number of factors such as temperature and seasonal variations, the presence of fungus or microorganisms in the soil, moisture content and rainfall etc.

L, fcv it v-f ^ Another useful nutrient, other than those already described, can include the typical liquid waste from many meat processing plants, which is often rich in animal protein. Animal protein is a useful nutrient source for many biologically active materials which may be encountered in the soil.

Nutrients may be introduced to the mineral substrate in a variety of manners. For instance if provided in a dry form, they may be dusted or coated onto mineral substrate. Where the mineral substrate exists in a substantially powered or granular form, dry nutrients may merely be blended in to the mixture. In embodiments where pellets are manufactured, rather than relying on natural granules of a substance, it may also be possible to use 'dry' nutrients.

Where the mineral substrate is present in larger lumps (though this may also be applied to other forms) it may be easier to apply a liquid based nutrient which can be used to impregnate the particles. This may comprise making an aqueous solution of the desired nutrients though many nutrients may already come in a liquid form able to be directly applied. In this case the granule or pellet must be porous to the solvent chosen. A greater degree of control over porosity is possible for manufactured pellets though most rock phosphate and other minerals are porous to and will absorb water and common solvents.

Targeted fungi for the selection of nutrients in the present invention include members of the genus Aspergillus, Fusarium and Penicillium. Most members of these fungal groups are useful though in particular the following may be specifically targeted: \ 1 11 ! m s w t Fusarium Oxysporum, Fusarium Solani, Aspergillus Niger, Aspergillus Candidus, Aspergillus Flavus, Aspergillus Ustus, Penicillium Janthinellum., and Sclerotium Rolfsii.

Some other micro-organisms which may be targeted for establishment include Bacillus Megatherium Phosphalicum and strains thereof, Gram-positive bacteria and members of the genus. However it is to be noted that the foregoing lists are not meant to be exhaustive but are provided by wajr of example only and that not all members of species named in general may always be useful for soil chemistry.

Various other modifications may be made to a fertiliser composition according to the present invention. For instance, a coating may be applied to the particles of the composition. This may comprise a gelled layer, which could also include the nutrient. A thickened seaweed and fish based fertiliser is available upon request from Moana Fertilisers Limited of Waiuku, New Zealand. In this case the increased proportion of seaweed gels the fish fertiliser through additional gelling agents may be required.

Alternatively the coating may be nutrient free, with nutrients (if provided) being introduced into the particles or mineral substrate.

The coating may swell when wetted (in the field) and thus allow fungus or organisms to begin to grow on the coating and spread to the particle. A hydrating cross linking polymer may be used. A zeolite coating may also be used. Some zeolites and clays may effectively coat the surfaces of 12 particles and act as a porous support for encouraging biological growth.

As another example of modifications, the nature of the composition will effect how it may be used and applied. Typically it is preferred that the end product is a substantially dry flowable material as this would enable its application by relatively common dry material spreaders. In many cases the available fertiliser spreading equipment will still manage a damp product though it is still generally desirable that the composition is able to flow. The use of hydrating agents and constituents has been described to absorb excess moisture which may be added during various stages of production. However it is also noted that a distinction is to be made with hygroscopic and deliquescent materials which could continue absorbing moisture from the atmosphere and result in a 'wet' product. Consequently, where possible, the use of hygroscopic or deliquescent materials should be eliminated or reduced.

A modification which may be incorporated into the invention is to coat, impregnate or otherwise treat particles with an agent able to promote their free flow. Many dusting agents such as talc, various sterates etc could be used in this regard. Some of these may also be partially water repellant which can be useful in preventing further absorption of water by the particles. However a coating agent which will be readily removed after application of the fertiliser composition is generally preferred unless a slow or delayed release product is desired. Other materials, which reduce moisture loss (and which need not necessarily comprise a free flow agent), may also be applied.

Particle size is a matter of user choice and will also be influenced by the method of manufacture. It is envisaged that most embodiments of the 13 2f'0 79 present invention will have an average particle size such that at least 90% will be able to pass though a sieve with a mesh size of 10mm by 10mm. This would be regarded as a coarse embodiment and may not find universal application. Probably more useful is a finer grade in which 5 90% of the particles will pass through a sieve with a rectangular mesh of 3mm by 3mm. In ultra fine embodiments, the composition may be substantially powdered.

Best Modes for carrying out the Invention Further aspects and advantages of the invention will become apparent 10 from the ensuing examples, which are not intended to be restrictive but to illustrate but some aspects of the present invention.

Example 1 A nutrient solution capable of promoting the growth of a suitable fungus and micro-organism in a soil is prepared. A targeted organism could be, 15 for instance, a fungus of the family Fusarium though need not be restricted to this alone. The nutrient solution in a preferred embodiment is a non-heat treated fish based fertiliser such as available from Moana Fertilisers Limited, Baldhill Road, Waiuku, New Zealand though other preparations could also be used. For instance, the nutrient may be an 20 aqueous solution of ammonium or another nitrate. The greater range of nutrients in the fish fertiliser would however tend to provide an improved fertiliser product with a greater range of fertilising nutrients.

As previously mentioned, the fish base composition can be considered to be a relatively rich source of amines and nitrogen, which are readily 25 converted by soil present bacteria and fungi into other products including 14 M»079 in many cases, free ammonia. Other present soil bacteria may then nitrify this free ammonia with the associated process solubilising phosphate present. Another possible nutrient source is an animal protein base composition, such as the liquid waste from many meat 5 processing and rendering plants. Even if not plentiful in plant available nitrogen, these forms of nutrients typically comprise a rich broth particularly suitable for the rapid establishment of fungal or microbial colonies. The use of sewage could be considered though the difficult here is that the presence of pathological organisms may require its prior 10 treatment which can effect the composition. In addition, treated sewage is typically fairly dilute and may require concentration (and associated expense) for use in certain embodiments of the present invention. Sewage as a nutrient source could be considered though the foregoing problems will often preclude its use and thus a fish or animal protein 25 based waste or fertiliser composition may be considered.

The substrate in this example is a commercially available rock phosphate broken down to an acceptable size. An average size of 3mm or less is considered to be useful.

To the substrate is added, in an aqueous form, the nutrient solution 20 which is absorbed into the rock phosphate to impregnate it. While virtually any ratio of substrate: liquid may be used, it is preferable to use lower quantities of liquid if a substantially dry product is to be obtained. While slurries or suspensions of substrate may be used and are within the scope of the present invention, it is envisaged that these liquid forms 25 are more suitable for application of the invention rather than as a form which may be stored for some time before application. If necessary, substantially dry forms may be converted into a slurry or liquid form prior to application.

In trials, less than 25% liquid (by weight) was added to the substrate, with around 10% being preferred for obtaining a substantially dry product. Once impregnated, the product may be dried though considerations include the extra time and cost for drying and the effect of excess drying on the fungus or micro-organism. It is envisaged that in most , but not all cases, the product will have a free moisture content (by weight) of less than 25% and more likely 5-15% inclusive. By free moisture is meant water not present as waters of crystallisation of various components. The use of components able to remove excess water through crystallisation, or through a physical (e.g. zeolites) or chemical reaction (e.g. gypsum, calcium sulfate monohydrate, unslaked lime etc.), may also be used to create a product having the preferred water content and allow the addition of more dilute nutrient solutions during impregnation but still provide a substantially dry product.

Example 2 Here a substrate comprises a manufactured pellet. By way of example it may contain the following constituents: Component % by weight [to total of 100%] gypsum up to 100% lime up to 100% aluminosilicate up to 100% rock phosphate up to 100% an inorganic fertiliser or mixture up to 90% containing nitrogen and I or potassium and I or trace elements mineral or vegetable or other oil up to 15% water up to 25% 16 Various aluminosilicates may be used and the term includes within its ambit clays such as kaolinite, bentonite, etc., and zeolites of which many are commercially available.

Inorganic fertilisers generally include mineral and synthetic products, including various nitrates, phosphates, sulphates, chlorides etc. It shall not generally include materials based on organic materials such as plant or animal matter.

A relatively porous pellet is obtained which is impregnated with a nutrient mixture in the same manner as example 1.

Example 3 Here the product comprises either a manufactured pellet or blend of components which may be substantially particulate or powdered in form. The constituents are as follows: Component % by weight [to total of 100%] rock or insoluble phosphate 35-80% bentonite or bentonite predominant aluminosilicate 20-65% liquid nutrients comprising at least one of an ammonium containing nutrient, an amine containing nutrient, a fish based composition, an animal protein based composition 0-15% 17 14ie?3 Example 4 A fertiliser composition which comprises, be weight to a total of 100%: Rock phosphate or insoluble phosphate 5-99.999% Nutrient 0-95% - Non-phosphate mineral substrate 0-95% Example 5 As for examples 2 or 4 in which the nutrient chosen is a liquid fish based fertiliser. A suitable product is that available from Moana Fertilisers Limited of Waiuku, New Zealand.

Example 6 As for examples 5 through 8 in which a hydrating constituent (preferably reversible) is included. This may comprise the use of a gel such as agar and may comprise the use of a seaweed-fish based fertiliser such as available from Moana Fertilisers Limited of Waiuku, New Zealand. Another option is the use of the product AGROSOKE™. For pelleted embodiments, polymeric or dry hydrating agents may be blended with the other dry constituents prior to pellet formation.

Example 7 This embodiment comprises a coated pellet in which the coating is a gel-20 like covering suitable for the rapid establishment and growth of 18 contained biological material. Preferably this embodiment is directed to pelleted type embodiments where any one particle substantially comprises a substantially homogeneous blend of components. However, it could also be applied to non-pelleted mixtures, in which case it is preferred that the constituents are substantially non-powdered and preferably also not the larger or coarser sizes. It is envisaged that particle or pellet sizes which fall predominantly within the average size range of 2-5mm diameter will be most applicable for this particular embodiment though it is noted that a larger size could be tolerated for substantially homogeneous pellets.

The method comprises the application of a suitably viscous coating to particles. These particles could be any of the products from the previous examples, though with the above recommendations in mind. The nature of the coating is typically that of a gel and it is preferable that a gel which will further harden, perhaps via a setting reaction or through the loss of water, is used. Typically the gelled coating will be applied while still in a fluid or semi-fluid state, though will eventually form a discrete coating on each particle which should not clog or bind particles together into a sticky mass.

Several methods may be used to achieve this. For instance, many gelling materials such as agar and gelatine (among other examples), have a setting reaction. Consequently, these type of gelling agents may be used for the coating and applied before the setting reaction has climaxed.

As an alternative, moisture absorbent materials or hydrating agents within the particle could promote the formation of a suitable coating. 19 As a further modification, a free flow agent could be dusted or applied to the resulting coated particles to reduce the further possibility of particles sticking or binding to each other in the bulk form.

The coating may comprise a nutrient, such as the liquid fish based fertilisers available from Moana Fertiliser Limited. Other liquid nutrients could also be used, or a solution of solid nutrients. The use of a thicker seaweed based fish composition from Moana Fertiliser, or the equivalent, is also possible though additional gelling agents may be added prior to its application. If the coating of interest is sufficiently fluid, then rather than a discrete coating on the particle, the outer surface layers may impregnated so that an outer crust comprising part of the intended coating and part of the substrate may be formed. In some instances this can be just as effective as a discrete gelled coating.

Example 8 A rock phosphate mineral is milled to a particle size of typically between 3-10mm. To this is introduced a nutrient comprising a fish based composition and/or an animal protein based composition. Again a fish base fertiliser, or a fish plus seaweed based fertiliser is currently available under the name MOANA, or MOANA PLUS, available from Moana Fertilisers Limited, or the equivalents are acceptable. These particular products are given by way of example only.

The method of introduction is typically by slow introduction of the liquid content to the rock phosphate in a ribbon blender. Spray application of the .t . . O - t.- liquid components into the mineral substrate within the mixing vat is preferred for even distribution. The liquid components will typically comprise between 5-15% of the total weight of the combination. If more concentrated or diluted nutrient compositions are used, then these 5 proportions may vary. It is noted that a wide degree of variation exists for the quantity of nutrients added. Typically the quantity of nutrient present will be sufficient to establish or accelerate growth of preferred fungi or micro-organisms within the soil. However, the proportion of nutrients may also be increased so that the fertiliser composition which results is 10 also able to supply other elements than phosphorus. For this example, it will be assumed that the foregoing proprietaries fish based fertilisers will often be diluted between 5:1 and 15:1.

The product is essentially completed after blending though the product may be allowed to dry (either by artificial or forced drying, or natural or 15 air drying) before storage or transport.

Example 9 To the product of Example 8, is applied a thickened gel coating. Typically the gel coating comprises a nutrient source such as described for Example 8 though this may be in a more greatly diluted form. Gelling or 20 thickening of the coaiing may be achieved through the use of a sufficiently viscous product (e.g. some seaweed containing fertiliser compositions) or a gelling agent such as gelatine, agar or the equivalent may be added prior to coating. The coating may also be applied in a ribbon mixer and as for Example 8 the fluid coating may be applied by 25 spraying or showering it onto the particulate material in the mixing vat. 21 'N. ,4, J. w i J Most agar or gelatine type compositions will set though this will often be accelerated to some extent as the substantially dry phosphate material absorbs moisture from the coating.

It may be desirable to continue agitation of the mixture until the coating 5 or impregnation of the surface is substantially complete, to avoid clumps of gelled material arising.

Also as an option, a free flow agent, such as talc or various stearates, may be applied to dust the individual coated particles.

Application of the coating may be via a number of known methods, 10 including a ribbon blender. However to some extent the method of coating will depend upon the viscosity and proportions of components.

Nature of product.

In most cases the product will comprise a pellet or granule with a relatively low moisture content (25% or less and preferably 5-15%). The 15 average particle size will often be 10mm or less, and more preferably 3mm or less. In most cases the granular forms will remain flowable though the moisture content will often mean less dust, which may be an advantage in many cases.

The pellet of most embodiments will comprise essentially a binder 20 incorporating nutrients directed to establish the growth of targeted fungi and/or micro-organisms. Typically the product will be porous as many embodiments rely upon liquid impregnation to introduce some of the components. Porosity also allows the product to release nutrients when 22 wetted or rained upon. Porosity also influences how accessible the pellet/granule is to fungus or microbial growth and also how rapidly the product decays or releases its contents.

The product also represents a means of preparing a solid or 'dry' fertilising composition from a liquid fertiliser. This may in practice provide advantage as many fertilisers are transported in a dry form and consequently a large amount of equipment is adapted for dry or solid material. At least on embodiment of a product also represents a high phosphorus fertiliser which also contains other nutrients, according to the impregnated components. Phosphates are generally applied on their own or with lime - the present invention represents a means by which additional elements can be applied during the same operation.

Also, the nutrients will often tend to be released at a relatively slow rate, at least compared to a liquid fertiliser applied to pasture. This may be advantageous in areas of high rainfall where many liquid and some readily soluble solid fertilisers would be quickly washed from the soil. The rapid establishment of the fungus or other preferred microorganisms may further regulate rapid leaching of nutrients from the product.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. 23 24

Claims (31)

WHAT WE CLAIM IS:

1. A fertiliser composition comprising: a mineral substrate, and - an introduced nutrient source for rapidly establishing the growth of phosphate solubilising fungi and/or microbes.

2. A fertiliser composition as claimed in claim 1 in which said introduced nutrient is an available nitrogen containing nutrient.

3. A fertiliser composition as claimed in either claim 1 or claim 2 in which said introduced nutrient includes an ammonium compound, or an amine.

4. A fertiliser composition as claimed in any one of the preceding claims in which said nutrient comprises a fish based composition.

5. A fertiliser composition as claimed in any one of the preceding claims in which said nutrient comprises an animal based protein composition.

6. A fertiliser composition as claimed in any one of the preceding claims in which said mineral substrate comprises a rock phosphate and/or an insoluble phosphate, as herein defined.

7. A fertiliser composition as claimed in any one of the preceding claims in which said mineral substrate includes at least one member of a group comprising: aluminosilicate (as herein defined), lime, zeolite, clay, and phosphate minerals.

8. A fertiliser composition as claimed in any one of the preceding claims which includes a binder for cementing constituents together. 2A W /335 24 1 07 /

9. A fertiliser composition as claimed in any one of the preceding claims which includes a hydrating constituent in a substantially hydrated form.

10. A fertiliser composition as claimed in any one of the preceding claims which includes a hydrating constituent in a substantially non-hydrated form.

11. A fertiliser composition, as claimed in any one of the preceding claims, in a substantially dry, flowable form.

12. A fertiliser composition as claimed in any one of the preceding claims in a granular or pelleted form.

13. A fertiliser composition as claimed in claim 12 in which the granules or pellets are of a size such that at least 90% by volume will pass through a sieve with a rectangular mesh of 10mm by 10mm.

14. A fertiliser composition as claimed in claim 12 in which the granules or pellets are of a size such that at least 90% by volume will pass through a sieve with a rectangular mesh of 3mm by 3mm.

15. A fertiliser composition as claimed in claim 12 or any claim dependent thereon, in which granules or pellets of the composition have been coated with a nutrient support.

16. A fertiliser composition as claimed in claim 12 or any claim dependent thereon, in which the surface layer of the granules or pellets of the composition have been impregnated with a nutrient support.

17. A fertiliser composition as claimed in claim 15 or claim 16 in which said nutrient support comprises a gel. f V j 0 25 c-1 /f'*\ •/ h " i ^ t

18. A fertiliser composition as claimed in claim 17 in which said nutrient support comprises a gelled fish based composition.

19. A fertiliser composition as claimed in claim 17 in which said nutrient support comprises a gelled animal protein based composition.

20. A fertiliser composition as claimed in any one of claims 15 through 19 in which said nutrient support includes a cross linked polymer.

21. A fertiliser composition as claimed in claim 12 or any claim dependent thereon in which said granules or pellets have been treated or coated with a free flowing agent.

22. A fertiliser composition as claimed in any one of the preceding claims in which the introduced nutrient or nutrient support has been chosen for the rapid establishment of a targeted fungus or microbe common to the soil in the intended area of application of the fertiliser composition.

23. A fertiliser composition as claimed in any one of the preceding claims in which the introduced nutrient or nutrient support has been selected for the rapid establishment of a member of the group consisting of: gram positive bacteria, members of the genus Aspergillus, members of the genus Penicillium, members of the genus Cylindrocladium, members of the genus Pseudomonas, and members of the species Fusarium oxysporujn, Fusarium solani, Sclerotium rolfsii, and Bacillus megatherium pliospaticums. f-8 '! <S V IV! A iO:i: 26 \ u

24. A fertiliser composition as claimed in any one of claims 1 through 22 in which the introduced nutrient or nutrient support has been selected for the rapid establishment of a member of the group consisting of: members of the species Aspergillus niger, Aspergillus candidus, Aspergillus flavus, Aspergillus ustus and Penicillium janthinellum.

25. A method for the production of a particulate fertiliser composition comprising the introduction of a nutrient source for rapidly establishing phosphate solubilising fungal or microbial growth, to a mineral substrate.

26. A method as claimed in claim 25 in which said mineral substrate comprises a phosphate material.

27. A method as claimed in either claim 25 or claim 26 in which a said mineral substrate comprises a rock phosphate or insoluble phosphate, as herein defined.

28. A method as claimed in any one of claims 25 through 27 in which the introduced nutrient is in a liquid form which is applied to the mineral substrate.

29. A method as claimed in claim 28 in which the liquid nutrient is allowed to impregnate or coat said mineral substrate.

30. A method as claimed in any one of claims 25 through 29 in which a nutrient support is coated onto, and/or allowed to impregnate into, the surface of particles of the mineral substrate.

31. A method as claimed in claim 30 in which said nutrient support is in addition to nutrients previously introduced to the mineral substrate:' . 27 "f r • 0 u;,i