WO1996022359A1

WO1996022359A1 - Plant growth stimulating composition

Info

Publication number: WO1996022359A1
Application number: PCT/US1995/016907
Authority: WO
Inventors: Craig Jones; D. Michael Bitz
Original assignee: E.K.M.A., Inc.
Priority date: 1995-01-20
Filing date: 1995-12-28
Publication date: 1996-07-25
Also published as: US5811276A; AU4645796A; TR199600051A2

Abstract

The present invention relates to a composition capable of stimulating plant growth and to a method of preparing such a composition. A culture is prepared by exposing the culture obtained from a starting culture of gastrointestinal microorganisms to a magnetic field. The exposure of the culture to a magnetic field is performed between two magnets of like poles of which are specifically the north poles that face the flow path of the culture separated from its food source. A food source is used during the process in which to culture a sample of the microorganisms obtained from a nutrient containing culture medium in which to isolate a culture of microorganisms for use in a plant growth stimulating composition. The plant growth stimulating composition further contains a nutrient formulation of Na, Cl, P, Mg, Ca, S, Zn, Cu, Fe, K, Mn, Mo, Si, B, Ni and Rb.

Description

PLANT GROWTH STIMULATING COMPOSITION

This is a continuation-in-part of Application No. 08/376,553, filed January 20, 1995, the entire contents of which are hereby incorportated by reference.

TECHNICAL FIELD

The present invention relates to a composition capable of stimulating plant growth and to a method of preparing such a composition.

BACKGROUND

Plant growth stimulating compositions have application in a number of areas, including farming and commercial and residential landscape maintenance. Various growth stimulating compositions are available that are derived from natural or from synthetic sources. The compositions of the present invention have constituents from both sources and have the advantage of superior growth stimulatory properties. The compositions of the present invention have the further advantage that they can be tailored so as to be optimum for a particular plant type growing under particular soil conditions. OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a composition capable of stimulating the growth of plants. It is another object of the invention to provide a method of treating a microbial culture so as to render it suitable for use as a constituent of a plant growth stimulating composition.

It is a further object of the invention to provide a nutrient formulation suitable for use as a constituent of a plant growth stimulating composition.

In one embodiment, the present invention relates to a method of preparing a culture of microorganisms for use as a constituent of a plant growth stimulating composition. The method comprises: i) obtaining a starting culture sample of microorganisms from the gastrointestinal track of a mammal; ii) culturing the sample in a medium comprising sodium, potassium, calcium, magnesium, inorganic phosphorus and chlorine or salts thereof; iii) culturing the sample resulting from step (ii) in the presence of a food source comprising a grain or a grass; iv) separating the culture of microorganisms resulting from step (iii) from the food source; and v) exposing the culture resulting from step (iv) to a magnetic field. In a further embodiment, the present invention relates to a plant growth stimulating composition comprising a culture of microorganisms produced by the above method and a nutrient formulation comprising Na, Cl, P, Mg, Ca, S, Zn, Cu, Co, I, Se, Fe, K, Mn, Mo, Si, B, Ni and Rb. In yet a further embodiment, the present invention relates to such a nutrient formulation.

In still another embodiment, the present invention relates to method of stimulating the growth of a plant. The method comprises administering to the plant the above composition under conditions such that the stimulation is effected.

In yet another embodiment, the present invention relates to a method of preparing a culture of microorganisms for use as a constituent of a plant growth stimulating composition comprising exposing the culture to a magnetic field under conditions such that thickening of the cell walls of the microorganisms, as determined by light microscopy, is effected. Further objects and advantages of the present invention will be clear from the description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1. Diagram of fermentation tanks for preparation of microbial cultures.

Figure 2. Diagram of orientation of magnets relative to recirculation tube.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method of preparing microbial cultures for use as constituents of a plant growth stimulating compositions. The invention also relates to nutrient formulations to be used in combination with such microbial cultures in the growth stimulating compositions. The cultures and formulations of the invention can be used to stimulate the growth of a variety of plant types including sugar cane, vegetables, fruits, grasses and tropical plants. The cultures and formulations can also be used to advantage on ornamental plants.

Starting cultures suitable for use in preparing the microbial cultures of the invention can be obtained by combining isolates of specific microbial strains or by obtaining a mixed culture from an animal, for example, from the gastrointestinal track of an animal, preferably, a mammal, more preferably a herbivore, most preferably a cow (eg a lactating cow) . Starting cultures can be obtained, for example, from a sample aspirated from the stomach of an animal (eg from the rumen of a herbivore) or from a fecal sample taken from the intestinal track of an animal.

The starting culture, whether obtained from a natural source or prepared from isolates, is cultured for an initial period (eg 21 to 31 hours, preferably, 24 hours) in the presence of a medium that can be prepared from natural sources (eg from the saliva of a herbivore (eg a cow)) or from chemicals. When prepared from saliva, the following procedure can be used. A bolus (eg about 1 liter) is taken from the mouth of the animal (eg a cow) and placed on a filter (eg about an 80 micron filter) . The bolus is washed with warm water (about 10 liters of water per liter of bolus) and the filtrate (pH preferably about 6.3 to 6.8) is obtained and used as the initial culture medium.

When synthetic medium is used, it is preferably formulated so as to contain the following: sodium potassium calcium magnesium inorganic phosphorus chloride

As an example, a culture medium containing the following can be used:

Sodium bicarbonate .0225.g/liter

Potassium bicarbonate .00125 g/liter

Calcium carbonate .000025 g/liter Magnesium carbonate (anhydrous) .0000375 g/liter Phosphoric acid .003375 g/liter

Chloroacetic acid .002125 g/liter

The concentrations of the culture medium components can vary depending on the starting culture and on the target plant, however, typically concentrations vary, for example, by plus or minus 45%, preferably, plus or minus 20% from the above.

The starting culture sample is incubated in the culture medium, preferably, at a pH in the range of 6.9 to 7.3. Adjustments in pH can be made at this point and throughout the process using a variety of acids and bases, sulfuric, hydrochloric and citric being the preferred acids, citric being more preferred, and potassium hydroxide, calcium hydroxide and sodium bicarbonate being the preferred bases, sodium bicarbonate being most preferred. During this initial incubation period, and throughout the process, air is introduced (eg by compressed air injection) to maintain an oxygen content in the range of 3 to 5 ppm (oxygen, nitrogen and argon being the major components of compressed air) . During this initial period, nitrogen, sugar and oxygen uptake occurs. Cells increase in number, nutrient content and in cell-wall content. A food source (substrate) is subsequently (eg after about 23 to 28 hrs, preferably 24 hrs) added to the medium/starting culture sample mixture. The food source can comprise a mixture of feed grains and grasses. Preferably, at least three of the following are added in approximately equal parts by weight:

crushed corn oats milo alfalfa sunflower seeds peanuts (whole) wheat soybeans barley rice flax.

For sugar cane and vegetable crops, a mixture of crushed corn, oats, alfalfa and whole peanuts is preferred. The same is advantageous for tropical plants. When grasses are the target plant (eg in the case of golf course maintenance) , a mixture of crushed corn, oats, alfalfa and flax is preferred. The food source is typically added to the medium/starting culture sample together with a further volume of liquid (ie culture medium and water (eg in a ratio of about 1:5 to 1:4)) in a ratio of about 1 kg of dry matter to about 7-8 liters of liquid. Multiple additions of food source and liquid to the original medium/starting culture sample can be made, 2 additions at approximately 24 hour intervals being preferred. Throughout this period of incubation, an approximately neutral pH is maintained, a pH in the range of about 6.9 to about 7.3 being preferred. The temperature is maintained, preferably, in the range of about 34° to 41°C, 37° to 40°C being preferred.

After the final addition of food substrate, the resulting broth is well mixed, for example, by recirculating the broth in a recirulation tank. The recirculation is typically for a period of about 24 hours, after which time the broth is allowed to stand for a period sufficient to allow the particulate matter to settle out.

An aliquot of the broth supernatant is then removed and placed in a second container (tank) . By separating the supernatant aliquot from the particulate matter, the microorganisms present in the aliquot are separated from their food source (thereby causing a "secondary shunt metabolism" to be effected) . The pH of the transferred aliquot is slowly reduced (eg over a period of several hours) to about 4.5 to about 6.3, 5.1/5.8 to 6.3 being preferred, 5.1 to 6.1 being more preferred (the pH can in fact range from 3.4 to 9.0). The temperature is maintained in the range of about 34°C to 41°, 37° to 41°C being preferred. A minimal amount of a second food source is added (eg about l%-3% v/v of the aliquot, 3% being preferred) . The second food source is, for example, molasses (eg sugar cane or citrus molasses) , aloe vera, papaya juice, εtearate or glycogen. Sugar cane molasses is preferred when sugar cane or grass is the target plant, citric molasses being preferred in the case of citrus and vegetable crops as well as tropical plants (papaya juice can also be advantageous in the case of tropical plants) .

At this point in the process, the number of cells per ml is, advantageously, in the range of 700,000 to

1.5 million, about 850,000 cells/ml to 900,000 cells/ml being preferred, around 890,000 cells/ml being most preferred. The cell count can be increased by delaying the transfer of the aliquot from the first tank to the second.

After the pH has been reduced and the second food source added, an aliquot of the culture is recirculated through a magnetic field. The field is created using an electromagnet or permanent magnets, for example, rare earth magnets. In the case of permanent magnets, an appropriate field can be created, for example, by two opposing magnets. Magnets suitable for use in the present invention have a strength in the range of 1200 to 4500 gauss, about 3500 gauss magnets being preferred. Figure 2 includes a diagram of a preferred orientation of such magnets. While, in the Figure, like poles (ie north poles) are shown to face either side of the recirculation tube, such need not be the case (e.g. opposite poles can also face the tube) . In addition to the use of magnets as described above, magnetic fields can also be generated by particle movement.

The exposure of the microorganisms to the magnetic field results in an increase in the thickness of the microbial cell wall and an increase in cell mobility, as viewed under light microscopy. The invention contemplates the use of magnetic fields that can achieve these ends .

During the process of recirculation through the magnetic field, a formulation of nutrients is added that includes Na, Cl, P, Mg, Ca, S, Zn, Cu, Fe, K, Mn, Mo, Si, B, Ni, and Rb, preferably, also Co, I, or Se. Generally, molybdenum, boron and magnesium are important to fermentation stimulation in the present process (together with the compressed air components) . Preferably, the formulation has the following composition and the concentration ranges listed (g/1) reflect the increase in concentration of the components in the culture upon addition of the formulation to the culture:

Broad range (g/1) Preferred Range (g/I)

Sodium bicarbonate .0001 -.10 .0005-.090

C loroacetic acid .0001 -.04 .0005-.03

Phosphoric acid (liquid) .001-.05 .002-.02

Magnesium carbonate (anhydrous) .000075-.05 001-.004

Calcium carbonate .000250-.300 .001-.004

Sulfur (from sulfates in composition) .000075-.04 .002- 006

Zinc stearate .00004-.008 .0003-.005

Copper sulfate .00000001-.06 .00000001-.00001

Cobalt acetate tetrahydrate .0000005-.0000000006 .00000004-.000000003

Iodine (liquid) .000000003-.000006 .00000005-.000000008

Se (plasma grade std (liquid)) .000000003-.00001 .00000002-.000001

Iron sulfate .0000002-.00009 .000005-00006

Potassium bicarbonate .05-.0006 .04-.006

Manganese sulfate monohydrate .000005-0045 .00045-.00003

Molybdic acid 85% (powder) .00000001-.00004 .00000019-.000005

Silicon (reference std solution (1000 ppm)) .0000005-.0005 .00005-.0001

Boric acid .000002-.0000000003 .00000003-.0000002

Nickle carbonate .000000005-.00005 .0000005-.000003

Rubidium chloride .000000009-.0000095 .00000006-.00000055 Other forms of the indicated elements can also be used so long as they are acceptable to the microorganisms.

Formulations advantageous for tropical plants, vegetables and grass (eg golf course grass) are as follows (expressed in g/1 of culture, the form in which each is added being as indicated above) (see Example for sugar cane values) :

Tropical Golf Course

Plants Vegetables Grass

Na .018 .018 .018

Cl .003 .003 .003

P .002 .002 .002

Mg .004 .0031 .0035

Ca .004 .004 .004

S .006 .006 .006

Zn .00003 .00003 .000038

Cu .00002 .00002 .00002

Co .00000008 .00000005 .000000009

I .0000008 .0000008 .0000008

Se .0000006 .00000045 .00000064

Fe .00006 .00006 .00006

K .006 .006 .006

Mn .00001 .00001 .00001

Mo .000003 .000004 .000009

Si .00001 .00001 .00001

B .000005 .000005 .000005

Ni .0000003 .0000003 .0000003

Rb .000007 .000007 .000007 These advantageous values (and those for sugar cane) can vary. The values for tropical plants can vary, for example, by plus or minus 59%, preferably, plus or minus 28%; the values for vegetables by plus or minus 430%, preferably, plus or minus 22%; the values for grass by plus or minus 450%, preferably, plus or minus 20%; and the values for sugar cane by plus or minus 45%, preferably, 20%.

Upon completion of the magnetic field exposure and nutrient formulation addition, the resulting composition can be used immediately or stored, for example, for as long as two years. During storage, the pH is preferably maintained at about 5 (eg 4.9 to 5.2) , however, a pH range of 5.5 to 6.5 can also be used. The temperature can be maintained between 5°C and 45°C, a temperature in the range of 34-41°C being preferred. Storage in the absence of ultra violet light is preferred.

The regimen used to apply the composition can be optimized for any particular plant. By way of example, 1.5 gallons of the composition can be applied per acre to a sugar cane crop per year in approximately four equal applications; about two gallons can be applied per acre of citrus grove per year in two equal applications; about 3 gallons can be applied per acre of golf course grass in two equal applications; and for vegetable crops, about 2-2.5 gallons can be applied per acre per year in two equal applications. In the case of tropical plants, about 1 gallon can be applied per acre per month. The composition is, advantageously, diluted about 20:1 with water and applied by the spraying of the diluted composition, however, other modes of application (eg irragation) can also be used. Foliar spraying is preferred in the case of tropical plants. Application of the composition results in a significant stimulation of plant growth. The composition can be applied alone or with other agents, such as insecticides and herbicides.

While not wishing to be bound by theory, it is believed that the advantages of the present invention result, at least in part, from the effects of components of the present composition on nitrofication which in turn enhances sulphur metabolism. In the fermentation process of the present invention, alcohols, aldehydes, organic acids, esters, ketones, phenols and sulphur compounds are believed to be produced. As it is understood, the sulphur compounds are of particular importance. As indicated above, boron and magnesium are expected to stimulate the fermentation process, along with oxygen, nitrogen, and argon (the major components of compressed atmospheric air) . When these constituents are added, they are believed to facilitate the nitrogen cycle of yeast present in the culture. As yeast convert sugar in the food substrate and the second food source, alcohols, esters and gums are formed (gums can include alginate, microbial gums, plant exudate and bean gum) . Groups of carbohydrates of particular interest include such gums and cellulose compounds, for example, those derived from the food substrate. The ability of yeast to uptake nitrogen is augmented by certain aerobic bacteria, azotabactors and cyanobactors, along with other nitrogen fixers. These bacteria are believed to be stimulated by molybdenum, boron and magnesium, which elements are believed to be important to the production of gums which, in turn, are important in sulfur metabolism. The importance of molybdenum, boron and magnesium is believed to result from the role played by these elements in the following enzymatic processes.

The process of nitrogen fixation requires the nitrogenase complex which consists of a reductase (which provides electrons with high reducing power) and a nitrogenase (which uses these electrons to reduce N₂ to NH4+) . Each component is an iron-sulfur protein in which iron is bonded to the sulfur atom of a cysteine residue and to inorganic sulfide. The nitrogenase component of the complex also contains one or two molybdenum atoms. The conversion of N₂ into NH⁴* by the nitrogenase complex requires ATP and a powerful reductant. In most nitrogen-fixing micro-organisms, the source of high potential electrons in this six-electron reduction is reduced ferredoxin. ATP binds to the reductase and shifts the redox potential of the enzyme from -0.29V to -0.40V by altering its conformation. ATP is hydrolyzed and the reductase dissociates from the nitrogenase component. Finally, N₂ bound to the nitrogenase component of the complex is reduced to NH⁴*. In relation to the phosphoryl transfer, a kinase catalyzes the transfer of a phosphoryl groups from ATP to an acceptor. Hexokinase catalyzes the transfer of a phosphoryl group from ATP to a variety of six-carbon sugars. Hexokinase requires Mg²* (or another divalent metal ion such as Mn²*) for activity. The divalent metal ion forms a complex with ATP.

Boron acids are another kind of transition state analog for enzymes that form acyl-enzy e intermediates. Acetylcholinesterase is an enzyme that catalyzes the hydrolysis of the ester bond in acetylcholine. Acetate and choline are two important substances in the formation of gums and waxes.

Sulfation is defined as any process of introducing an S0₄ group into an organic compound in which the reaction product (sulfate) exhibits the characteristic -0S0₃- molecular configuration. Sulfation involves the reaction wherein a -COS- linkage is formed by the action of a sulfating agent on an alkene, alcohol, or phenol. Unlike the sulfonates, which exhibit excellent hydrolytic stability, the alcohol sulfates are readily susceptible to hydrolysis in acidic media. Sulfation of fatty alcohols and polyalkoxy reductases occurs in the present process and the sulfation products lend themselves to detergent action as emulsifiers. Gums that are produced by the present process can store and stabilize products of microbial sulphur metabolism. Gums also serve generally to stabilize the fermentation components and thus facilitate storage of the product of the present method. The stabilization of the sulphur metabolism components allows immediate reaction with hydrocarbon chains in the environment by removing the sulfur link from those hydrocarbon chains for detergent reaction with associated alcohols. Basic fermentation processes of alcohols, aldehydes etc, break down components of plant cellulose and short chain carbon structures.

As indicated above, it is advantageous to maintain a pH of 5.1 to 6.1 during fermentation. As the fermentation process moves into the acid cycle, gums are formed. Once the gums begin to form, the pH ranges, for example, between 6.1 and 6.8 (this range can be broader, for example, 5.2 and 6.8) . Gums are anionic which makes them advantageous in storing the acidic fermentation products as well as by products of sulphur metabolism. The product of the present invention is believed to permit a more rapid conversion of the nitrogen cycle through ATP conversion to the sulphur complexes in anaerobic microbial production by the use gum and wax production phenomena. The chemistry of the present process is believed to divert sulfur metabolism so as to lessen the production of sulfites and mercaptans. Hence, the production of end-products such as hydrogen sulfite and methane, which are formed under anaerobic conditions where energy sources are apparently involved with hydrogen via dehydrogenase systems, are believed to be reduced.

Magnetism can alter the end-product production. By adjusting fields and field flux and making them permanent and/or oscillating along with altering bio- catalysts (eg proteins, vitamins, trace elements) and using the proper gas mixture of oxygen, nitrogen and argon, desired sulfur containing compounds are enriched, including α-linked purines, biotin, sulfinated carbohydrates, etc, and the levels of undesirable gases can be decreased. Magnetics, when combined with the present formulation, apparently provide for a more rapid conversion through the nitrogen and sulphur cycles to end complexes of sulphur metabolism. Certain aspects of the invention are described in greater detail in the non-limiting Example that follows.

EXAMPLE

Preparation of Composition for Stimulating Growth of Sugar Cane

Approximately a one liter sample is aspirated from the rumen of a 7.5 year old lactating Holstein cow using a rumen aspirator (Johnson and Johnson) . The sample is taken about 12-14 hours after feeding. Observed microscopically, the sample includes Clostridia, Baccilus, Azotabacter and protozoa (at least 100 cells of each per ml of sample) . The one liter sample is added to a culture medium (169 liters) that includes:

Culture medium:

Sodium bicarbonate 3.80 g Potassium bicarbonate 0.21125 g

Calcium carbonate 0.004225 g

Magnesium carbonate (anhydrous) 0.0063375 g

Phosphoric acid 0.570375 g

Chloroacetic acid 0.359125 g The sample and the culture medium (Mixture A) are maintained in Tank 1 (see Figure 1) at a temperature of 37°C and at a pH in the range of 6.9-7.3 for a first 24 hour period. At this stage, and throughout the process, pH adjustments are made using citric acid or sodium bicarbonate, as appropriate. During this first 24 hr period, Mixture (A) is agitated by the injection of compressed air which results in the presence in Mixture (A) of about 3-5 ppm oxygen. At the end of the first 24 hour period, Mixture

(B) is added to Mixture (A) in Tank 1. Mixture (B) comprises 140 liters of water, pH 7.0-7.1, and 30 liters of the culture medium described above into which air has been injected to achieve an oxygen content of 3-5 ppm. Mixture (B) also includes approximately 20 kg of a substrate comprising the following in approximately equal parts by weigh :

Substrate: crushed corn oats alfalfa whole peanuts

The pH of Mixture (B) is maintained at about 7.1 to 7.2, the temperature at about 34-40°C, and the oxygen content at about 3-5 ppm (by injection of compressed air) . These same conditions are maintained after the addition of Mixture (B) to Mixture (A) to form Mixture (C) . Mixture (C) is maintained in Tank 1 at about 37°C for a second 24 hr period with agitation by compressed air injection.

At the end of this second 24 hour period, Mixture (D) is added to Mixture (C) in Tank 1 to yield Mixture (E) . Mixture (D) , like Mixture (B) , comprises 140 liters of water, pH 7.1 to 7.2, and 30 liters of culture medium. Mixture (D) also includes 20 kg of the substrate described above. Mixture (E) is maintained in Tank 1 for a third 24 hr period with agitation by compressed air injection (temperature 40°C; pH 7.1; oxygen content 3-5 ppm) .

At the completion of the third 24 hour period, Mixture (E) is recirculated for ten minute periods. Tank 1, and the recirculation system associated therewith, is designed such that complete recirculation of Mixture (E) can be effected in the ten minute period. That recirculation is carried out at two hour intervals for a fourth 24 hour period. Mixture (E) is then allowed to stand for a time sufficient to permit particulate matter to settle out.

At the end of that fourth 24 hour period, 170 liters of Mixture (E) supernatant is transferred to Tank 2 (see Figure 1) . Compressed air is injected into Tank 2 to effect agitation of the aliquot of Mixture (E) present therein (Mixture (E-T2) ) and to maintain an oxygen content of 3-5 ppm. Mixture (E-T2) is maintained at a temperature of 37°-41°C and the pH is slowly reduced to 5.8-6.3 (ie over about a 3 hour period) and 3% (v/v) sugar cane molasses is added. The number of 96/22359

microorganisms present in Mixture (E-T2) is about 890,000 cells per ml.

Mixture (E-T2) (175 liters) is transferred to a further recirculation tank, Tank 3 (see Figure 1) and a "micronutrient" package is added. The contents of the package is formulated so that the addition thereof to the 175 liters results in the following concentrations, expressed as g/1 of Mixture (E-T2) :

Sodium bicarbonate .018 Chloroacetic acid .003

Phosphoric acid (liquid) .002

Magnesium carbonate (anhydrous) .002

Calcium carbonate .004

Sulfur (from sulfates in composition) .006 Zinc stearate .00003

Copper sulfate .00002

Cobalt acetate tetrahydrate .00000004

Iodine (liquid) .0000008

Se (plasma grade std (liquid)) .000001 Iron sulfate .00006

Potassium bicarbonate .006

Manganese sulfate monohydrate .00001

Molybdic acid 85% (powder) .000001 Silicon (reference std solution (1000 ppm) .00001 Boric acid .000005

Nickle carbonate .00000005

Rubidium chloride .000007 The content of Tank 3 (Mixture (E-T3)) is recirculated, and, during recirculation, is passed though a magnetic field (an 80 gal/min pump is used in the recirculation process) . The field is generated by six 3500 gauss rare earth magnets oriented as shown in Figure 2 with respect to a 1W diameter PVP 80 gauge recirculation tube, a 1/32" phenolic band being located between the magnets and the tube. During recirculation, the pH is maintained at between 5.5 and 6.5 and the temperature at about 37°C. Compressed air is injected during recirculation to maintain an oxygen content of 3-5 ppm. The composition resulting after 10 minutes of recirculation is stored for about 24 hours at a temperature of 35-38°C. The composition resulting from the foregoing process is applied to sugar cane by spraying four times per year for a total annual application of 1.5 gallons per acre.

* * *

All documents cited above are hereby incorporated in their entirety by reference.

One skilled in the art will appreciate from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A method of preparing a culture of microorganisms comprising: i) obtaining a starting culture sample of microorganisms from the gastrointestinal track of a mammal; ii) culturing said sample in a medium comprising sodium, potassium, calcium, magnesium, inorganic phosphorus and chlorine or salts thereof; iii) culturing the sample resulting from step (ii) in the presence of a food source comprising a grain or a grass; iv) separating the culture of microorganisms resulting from step (iii) from said food source; v) exposing said culture resulting from step (iv) to a magnetic field.

2. The method according to claim 1 wherein said starting culture sample is obtained from a herbivore.

3. The method according to claim 2 wherein said starting culture sample is obtained from the rumen of a cow.

4. The method according to claim 1 wherein said food source comprises at least one of corn, oats, milo, alfalfa, sunflower seeds, peanuts, wheat, soy beans, barley, rice or flax.

5. The method according to claim 1 wherein a pH of 6.9 to 7.3 is maintained in steps (i) to (iii).

6. The method according to claim 5 wherein, in step (iv) , the pH is adjusted to 5.8 to 6.3.

7. The method according to claim 1 wherein said magnetic field is that generated by at least two rare earth magnets each of 1200 to 4500 gauss.

8. The method according to claim 1 wherein said exposure to said magnetic field is effected by passing the culture resulting from step (iv) between two magnets wherein like poles of said magnets face the flow path of said culture resulting from step (iv) .

9. The method according to claim 8 wherein said like poles are north poles.

10. A culture of microorganisms produced by the method of claim 1.

11. A plant growth stimulating composition comprising the culture according to claim 10 and a nutrient formulation comprising Na, Cl, P, Mg, Ca, S, Zn, Cu, Co, I, Se, Fe, K, Mn, Mo, Si, B, Ni and Rb.

12. A nutrient formulation comprising Na, Cl, P, Mg, Ca, S, Zn, Cu, Fe, K, Mn, Mo, Si, B, Ni and Rb.

13. The nutrient formulation according to claim 12 further comprising Co, I or Se.

14. A method of stimulating the growth of a plant comprising administering to said plant the composition according to claim 11 under conditions such that said stimulation is effected.

15. The method according to claim 14 wherein said plant is sugar cane, a vegetable plant, a fruit tree, a tropical plant, or a grass.

16. A method of preparing a culture of microorganisms for use as a constituent of a plant growth stimulating composition comprising exposing said culture to a magnetic field under conditions such that thickening of the cell walls of said microorganisms, as determined by light microscopy, is effected.

17. A method of preparing a culture of microorganisms comprising: i) obtaining a starting culture sample of microorganisms corresponding to that of the gastrointestinal track of a mammal; ii) culturing said sample in a medium comprising sodium, potassium, calcium, magnesium, inorganic phosphorus and chlorine or salts thereof; iii) culturing the sample resulting from step (ii) in the presence of a food source; and iv) separating the culture of microorganisms resulting from step (iii) from said food source.

18. A culture of microorganisms produced by the method of claim 17.

19. A plant growth stimulating composition comprising the culture according to claim 18 and a nutrient formulation comprising Mg, Mo, and B.

20. A method of stimulating the growth of a plant comprising administering to said plant the composition according to claim 19 under conditions such that said stimulation is effected.

21. The culture according to claim 18 wherein said culture of microorganisms resulting from step (iv) comprises gums or waxes.

22. The method according to claim 17 wherein sulphur metabolites present in said culture of microorganisms resulting from step (iv) are stored or stabilized with gums or waxes.

23. The method according to claim 17 further comprising exposing said culture resulting from step (iv) to a magnetic field under conditions such that the rate of nitrogen or sulphur cycle occurring in said culture resulting from step (iv) is increased.

24. The method according to claim 17 further comprising exposing said culture resulting from step (iv) to a magnetic field under conditions such that the off-gasing of products deleterious to plants is increased.

25. The method according to claim 17 further comprising introducing argon, oxygen and nitrogen during steps (ii) , (iii) or (iv) .