WO2012095864A2

WO2012095864A2 - A plant nutrient composition and a process for preparing the same

Info

Publication number: WO2012095864A2
Application number: PCT/IN2012/000019
Authority: WO
Inventors: Chandan GADGIL
Original assignee: Innovative Environmental Technologies Pvt. Ltd.
Priority date: 2011-01-14
Filing date: 2012-01-06
Publication date: 2012-07-19
Also published as: WO2012095864A3

Abstract

There are provided a plant nutrient composition and a plant nutrient kit that is also useful modifying the pH of the soil. Both the plant nutrient composition and the plant nutrient kit employ bio-sulphur mass that is produced by the sulphur oxidation bacteria as a result of microbial oxidation. There is also provided a process for preparation of the plant nutrient composition of the present invention.

Description

A PLANT NUTRIENT COMPOSITION AND A PROCESS FOR PREPARING THE SAME

FIELD OF THE DISCLOSURE

The present invention relates to a plant nutrient composition and a process for preparing the same.

BACKGROUND

There is a growing demand for sulphur containing fertilizers worldwide. It has been found that in many cases the lower crop yields are on account of the sulphur deficiency in the soil. Sulphur by itself is difficult to be absorbed as a nutrient by plants. For the uptake of sulphur, it has to be converted into the sulphate form. Hence, most of the sulphur fertilisers available worldwide are in the form of sulphates e.g., ammonium sulphate, potassium sulphate and the likes. However, direct application of freely soluble sulphates in the form of ammonium sulphate and the likes could pose a threat due to leaching by excess irrigation or as a result of floods. It is because of this reason, one time application of such fertilizers to satisfy the sulphur requirement of the plant throughout its life cycle may not be desirable. Elemental sulphur, on the other hand is not soluble. It does not get leached out and can be converted fractionally into soluble sulphates by sulphur oxidising bacteria available in the soil. Sulphur oxidizing bacteria (e.g. Thiobacillus Thiooxidans) available in the soil have the ability to oxidize the elemental sulphur to ultimately produce H₂S0₄. The sulphate form thus produced is then absorbed by the plants as a nutrient.

Additionally, the H2SO4 formed as a result of microbial oxidation, along with providing soluble sulphates for plant uptake, has the ability to solubilize various other nutrients such as mineral oxides, rock phosphate, etc., making them available to the plants.

Further, it has been found that about 30% of soils across the globe are alkaline; i.e. they have a pH of 7.5 or above. Studies have shown that the availability and the uptake of essential nutrients and micro-nutrients by plants are maximum at a pH between 6.5 and 7.5. Above pH 7.5, the availability and hence uptake of nutrients like N, Ca, Mg, Fe, Mn, B, Cu, Zn are reduced to negligible amounts. Incorporating elemental sulphur in these alkaline soils can reduce the pH to the desired levels; however, the process may take plenty of years. However, the direct application of acid to neutralize these soils is also unfavourable as it may result in over- acidification and adverse impact on the soil environment. The controlled release of H2SO4 by means of controlled oxidation of elemental sulphur by the sulphur oxidizing bacteria allows the amendment of pH to take place without leaching.

However, in spite of its various advantages, using only elemental sulphur as a fertilizer may have a drawback that the conversion rate may be much slower than required and will be dependent on the amount of sulphur oxidizing bacteria available in the soil. The process of conversion may be expedited by inoculation with sulphur oxidizing bacteria.

Further, biologically prepared sulphur, on account of its micronic particle size and hence larger available surface area and an optimum pH of about 2.5 for the activity of acidophilic sulphur oxidizing bacteria available in the soil, can be used more efficiently as a fertilizer.

Various sulphur containing fertilizers and methods for preparing them are disclosed in US5653782, US Patent 3333939, US 5571303. In US Patent 7470304, there is disclosed a process for the manufacture of sulphur containing ammonium phosphate fertilizer that employs biologically prepared sulphur as one of the ingredients.

Further, sulphur containing fertilizers with various minerals microorganisms, like sulphur oxidizing bacteria have been disclosed in US3186826, JP1 1302649, CA2269301 and GB 104174.

OBJECTS:

Some of the objects of the present invention include:

It is an object of the present invention to provide a plant nutrient composition which provides controlled release of multiple nutrients to plants in absorbable form as per their requirement and the soil conditions in which they are planted.

It is also an object of the present invention to provide a plant nutrient composition which provides expeditious neutralization of alkaline soils, thus increasing the availability of multiple nutrients to the plants.

It is still further object of the present invention to provide a plant nutrient composition which is cost-effective. It is another object of the present invention to provide a plant nutrient composition which is easy to prepare and use.

It is still another object of the present invention to provide a plant nutrient composition which is eco-friendly.

It is another object of the present invention to provide a simple and economic process for the preparation of plant nutrient composition.

Other objects and advantages of the present invention will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present invention.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.

SUMMARY:

In accordance with a first aspect of the present invention there is provided a plant nutrient composition comprising bio-sulphur mass containing a first sulphur oxidizing bacteria and a second group of sulphur oxidizing bacteria. Typically, the bio-sulphur mass is produced by the first group of oxidizing bacteria.

Typically, the oxidation state of the bio-sulphur mass is predominantly zero. Typically, the pH of the bio-sulphur mass ranges between 2.5 and 8.5.

Typically, the first group of sulphur oxidizing bacteria is at least one selected from the group Thiobacillus thioparus, Thiobaccilus thiothrix, hiomicrospirafrisi, Thioalkalibacter halophilus, Thioalkalivibrio Thioalkalispira and Thiobacillus novellus.

Typically, the first group of oxidizing bacteria exhibit optimum activity at pH ranging between 6 and 9. Typically, the second group of oxidizing bacteria are acidophilic sulphur oxidizing bacteria. In accordance with one of the embodiments of the present invention, the second group of oxidizing bacteria is T.thiooxidans.

Typically, the second oxidizing bacteria exhibit optimal activity at pH ranging between 1 and 6.

In accordance with one of the embodiments, the plant nutrient composition of the present invention further comprises at least one nutrient selected from the group consisting of N, K, Fe, Ni, Co, Al, Zn, Mo.

In accordance with one of the embodiments, the plant nutrient composition of the present invention further comprises at least one excipient selected from the group consisting of bentonite, kaoline, gelatine, cellulose and xanthan gum.

In accordance with one of the embodiments, the plant nutrient composition of the present invention further comprises at least one mineral selected from the group consisting of rock phosphate and oxides, carbonates, acid addition salts of metals or elemental metals as such, said metals being selected from the group consisting of Zn, Ca and Mg, Fe, Bo.

Typically, the plant nutrient composition of the present invention is in at least one form selected from the group consisting of granules, powder, and compressed blocks. In a second aspect of the present invention, there is also provided a process for preparing the plant nutrient composition that comprises:

centrifuging/filterpressing/settling the washed or unwashed bio-sulphur mass and optionally drying it;

pulverizing the bio-sulphur mass to obtain a powder; admixing the culture of a second group of oxidizing bacteria with an excipient to obtain a granular mass; optionally, adding nutrients and minerals to the granular mass; mixing the powder and the granular mass to obtain a plant nutrient composition.

In accordance with a third aspect of the present invention, there is provided a plant nutrient kit comprising a container comprising a bio-sulphur mass containing a first group of oxidizing bacteria and a container containing a culture of second group of sulphur oxidizing bacteria.

Typically, the bio-sulphur mass is produced by the first group of oxidizing bacteria.

Typically, the oxidation state of the bio-sulphur mass is predominantly Zero.

Typically, the pH of the bio-sulphur mass ranges between 2.5 and 8.5.

Typically, the first group of sulphur oxidizing bacteria is at least one selected from the group consisting of Thiobacillus thioparus, Thiobaccilus thiothrix, Thialkalibacter Halophilus, Thioalkalivibrio, Thioalkalispira, Thiomicrospirafrisi and Thiobacillus novellus.

Typically, the first group of oxidizing bacteria exhibit optimum activity at pH ranging between 6 and 9.

Typically, the second group of oxidizing bacteria are acidophilic sulphur oxidizing bacteria.

In accordance with one of the embodiments of the present invention, the second group of oxidizing bacteria is T.thiooxidans.

Typically, the second group of oxidizing bacteria exhibit optimal activity at pH ranging between 1 and 6.

In accordance with one of the embodiments of the present invention, the container containing bio-sulphur mass further comprises further comprises at least one nutrient selected from the group consisting of N, K, Fe, Ni, Co, Al, Zn, Mo.

In accordance with one of the embodiments of the present invention, the container containing bio-sulphur mass in the kit of the present of invention further comprises at least one mineral selected from the group consisting of rock phosphate and oxides, carbonates, acid addition salts of metals or elemental metals as such, said metals being selected from the group consisting of Zn, Ca and Mg, Fe, Bo. In accordance with one of the embodiments, the container containing bio- sulphur mass in the plant nutrient kit of the present invention further comprises at least one excipient selected from the group consisting of bentonite, kaoline, gelatine, cellulose and xanthan gum.

BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1 provides a graph that shows the change in pH of the bio-sulphur mass sample over a period of time after water washing;

Figure 2 provides a graph that shows the comparative reduction in pH using the plant nutrient system of the present invention and the prior art composition containing elemental sulphur and sulphur oxidizing bacteria; Figure 3 provides a graph that shows the pH reduction achieved by plant nutrient system of the present invention and the prior art composition containing elemental sulphur as a function of time;

Figure 4 provides a graph that shows the extent of pH reduction in terms of percentage achieved by plant nutrient composition of the present invention and the prior art composition containing elemental sulphur during the experimental period; Figure 5 provides a comparative reduction in pH and the linear trend over a period of time by using the plant nutrient composition of the present invention and-the prior art composition containing elemental sulphur and sulphur oxidizing bacteria

Figure 6a shows the ground nut crop after 75days during the study in control group plot A

Figure 6b shows the ground nut crop after 75 days during the study in the plots in Group B

Figure 7 provides a graph that shows the correlation between the proportion of the sulphur oxidizing bacteria used in the plant nutrient system and the extent and pace of pH reduction.

DESCRIPTION OF THE INVENTION:

There has been tremendous need for sulphur containing fertilizers over the past years and a lot of effort has been taken in their manufacture. However, there has been very less research on the possibility of the use of bio-sulphur in the preparation of a fertilizer. The elemental sulphur is produced in the Sulphur oxidizing bacteria as a result of microbial oxidation, which is either stored inside the cell in the form of globules or is transported outside the bacterial cells in colloidal form. The oxidative state of the bio-sulphur mass is predominantly zero (S°) and it is an intermediate in the oxidation of sulphide to sulphates by sulphur oxidising bacteria that remain active in the pH ranging between 6 and 9. The term bio-sulphur mass as used in the context of the present invention particularly refers to the sulphur as described above.

As compared to conventionally known inorganic sulphur, the bio-sulphur mass is associated with numerous advantages which make it a near ideal ingredient for the preparation of a sulphur containing fertilizer.

Unlike inorganic sulphur, the bio-sulphur is in a colloidal form with sub- micronic particle size having an enormous surface area. This increased surface area of the bio-sulphur mass available to the sulphur oxidizing bacteria ensures a more efficient process of nutrient release/pH amendment than ordinary inorganic sulphur which is produced chemically.

Still further, in contrast to inorganic sulphur which is hydrophobic and is hardly soluble in water, the biologically produced sulphur is hydrophilic in nature and therefore it can be easily dispersed in water and the soil evenly, thus avoiding stratification and facilitating uptake by the plants.

In accordance with the present invention there is provided a plant nutrient composition that comprises:

a bio-sulphur mass inherently comprising a first group of sulphur oxidizing bacteria; a second group of sulphur oxidizing bacteria.

The first group of sulphur oxidizing bacteria is widely used in various biotechnological processes for the cleaning of sulphides, typically hydrogen sulphide, from a variety of gas streams including but not limited to biogas, syngas ,natural gas, acid/tail gas, sour gas. The first group of sulphur oxidizing bacteria inherently present in the thus prepared bio-sulphur mass of the present invention include Thiobacillus thioparus, Thiobaccilus thiothrix, Thiomicrospirafrisi, Thioalkalibacter halpohilus, Thioalkalivibrio, Thioalkalispira, Thiobacillus novellus. This inherently present first group of sulphur oxidizing bacteria in the biologically produced bio-sulphur mass is known to have optimal activity at pH ranging between 6 and 9.

The second group of bacteria employed in the plant nutrient composition of the present invention are acidophilic sulphur oxidizing bacteria which include Thiobacillus Thiooxidans. The second group of sulphur oxidizing bacteria exhibit optimum activity at pH ranging between 1 and 6.

The inherently present first group of bacteria play an important role in amending the pH of the bio-sulphur mass. These bacteria have the ability to reduce the pH of the bio-sulphur mass after water washing, typically from 8.5 (pH of the freshly prepared bio-sulphur mass ranges between 7 and 8.5) to as low as about 2.5 over a period typically ranging between 27 to 30 days. The strength of the acid produced by these bacteria, through microbial oxidation of the bio-sulphur however, is weak. The normality of acid formed due to microbial oxidation of the bio-sulphur mass by the action of the first group of bacteria is low, e.g. about 0.002N to 0.02N in about 25 days. As a result of this, the acid thus produced, does not produce over- acidification but it generates optimum conditions for the growth, survival and microbial oxidation by the second group of sulphur oxidizing bacteria present in the plant nutrient composition of the present invention.

In case of the plant nutrient composition of the present invention, the second group of bacteria engage in the microbial oxidation more efficiently, partly because of the larger available surface area due to the colloidal nature of sulphur particles present in the bio-sulphur mass and partly because of the reduced pH of the bio-sulphur mass on account of the microbial oxidation carried out by the inherent first group of sulphur oxidizing bacteria.

As a result of the increased efficiency, the bio-sulphur mass required to achieve a given pH amendment or to fulfil a given sulphate requirement of the plants is lesser than the amount of inorganic sulphur required for achieving the same pH amendment or to fulfil the same sulphate requirement in a fixed period of time.

At the same time, the amount of the second group of sulphur oxidizing bacteria required for achieving a certain pH amendment or to fulfil a certain sulphate requirement in fixed period of time is half if bio-sulphur is used instead of the conventionally known inorganic sulphur.

Also, for a fixed given amount of bio-sulphur mass and inorganic sulphur, to achieve a given sulphate requirement/pH amendment, the amount of time required by inorganic sulphur is 62% more than the bio-sulphur mass.

The rate at which sulphur is converted into sulphuric acid is controlled by the rate of microbial oxidation which in turn is adjusted by the amount of the second group of bacteria that are present in the plant nutrient system. Depending upon the soil conditions and requirement by plant, the proportion of the inoculated second group of sulphur oxidizing bacteria in the plant nutrient composition of the present invention can be adjusted accordingly and may range between 5 ml to 50 ml per 100 grams of sulphur with a count

Q

of about 10 per ml. The effect of the amount of the inoculated second group of bacteria on the time period required for changing the pH of the soil is shown in Figure 7.

Similarly, the amount of the bio-sulphur mass can also be adjusted depending on the amount of pH amendment/sulphur requirement to be achieved.

Thus, the degree of sulphate availability/pH amendment as well as the time in which it is achieved can be adjusted by controlling the amount of bio- sulphur mass as well as the proportion of second group of sulphur oxidizing bacteria, thus allowing the nutrient composition of the present invention to be designed for providing customized nutrient release/ pH amendment.

For example, for rapid pH amendments, biologically prepared sulphur are inoculated with larger proportions of the second group of sulphur oxidising bacteria, depending on the timeframe available for the amendment. For extremely alkaline soils where a higher degree of pH amendment is required, a larger amount of bio-sulphur mass can be added with regular proportions of second oxidizing bacteria. For even higher degrees of pH amendments to be carried out within a short time frame, a larger amount of bio-sulphur mass is added with a larger proportion of second group of oxidizing bacteria as well. Time frame within which the pH amendment is to be carried out is in turn decided on the basis of the nature and type of a crop and the specific soil type in which it is being cultivated. The same principle may be applied for use of the composition of the present invention as a nutrient. For crops with higher sulphur requirement, a larger amount of bio-sulphur mass are added. For crops with a sulphate requirement early in their life cycle, a larger proportion of second group of sulphur oxidizing bacteria are added to facilitate quick release.

For minor pH corrections/ sulphate availability to be made over a longer period of time, a sustained and controlled rate of microbial oxidation of the bio-sulphur mass is desired. Typically, the excipients could be of the type including but not limited to binding agents, dispersing agents, disintegrating agents, wetting agents, defoamer, stabilizers and the like. Typically, the binding agent can be selected from the group consisting of bentonite, gypsum, starch, pregelatinized starch, gelatin, vinyl chloride, povidone, hydroxyl propyl cellulose, ethyl cellulose, xanthan gum, cellulose acetate phthalate, hydroxyl propyl methyl cellulose, polyvinyl alcohols, phenyl naphthalene sulphonate, lignin derivatives, polyvinyl pyrrolidone, polyalkylpyrrolidone, polyethoxylated fatty acids, polyethoxylated fatty alcohols, ethylene oxide copolymer, propylene oxide copolymer, polyethylene glycols and polyethylene oxides.

The excipient is preferably selected from the group that includes bentonite kaoline, gelatine, cellulose and xanthan gum. with the second group of bacteria.

The rate of microbial oxidation and hence the release of

is dependent on the breakdown of the excipient. The bacterial activity begins only when the excipient comes in contact with water.

In accordance with one of the embodiments of the present invention, the composition of the present invention further comprises a mineral source with or without a nutrient. The mineral source used in the plant nutrient composition of the present invention includes rock phosphate and oxides, carbonates, acid addition salts of metals or elemental metals as such, said metals being selected from the group consisting of Zn, Ca and Mg, Fe, Bo. These minerals in the plant nutrient composition of the present invention, in- situ get converted into their respective soluble sulphate forms by the action of the second group of sulphur oxidizing bacteria in the presence of bio- sulphur, water and air.

The nutrient employed in the plant nutrient composition of the present invention, is selected from the group that comprises N, K, Fe, Ni, Co, Al, Zn, Mo.

In accordance with the present invention, there is also provided a process for the preparation of the plant nutrient composition of the present invention that comprises:

Typically, the plant nutrient composition of the present invention is in the form selected from the group consisting of suspension, mixture, powder, granules, pellets and compressed blocks. Another approach for controlling the extent and pace of the pH amendment in the soil is to select the bio-sulphur mass with a specific pH. When the rapid change in pH in short time frame is desired, the bio-sulphur with a pH of about 2.5 to 4 is employed. In cases, where a longer timeframe is desired for the amendment in pH then in such cases, the bio-sulphur mass with pH ranging between 4 and 8.5 is employed.

In accordance with another aspect of the present invention there is provided a kit comprising discretely packed bio-sulphur mass and second group of sulphur oxidizing bacteria. In accordance with one of the embodiments, the discretely packed second group of sulphur oxidizing bacteria are in the form of granules comprising an excipient, a nutrient and a mineral source. The kit of the present invention in one embodiment comprises the same set of excipient, nutrient and mineral source as described herein above.

In accordance with another embodiment, the discretely packed second group of oxidizing bacteria are in the form of a diluted culture containing 10⁸ /ml bacteria. This embodiment of the plant nutrient composition in the form of a kit has a longer shelf life since the second group of bacteria remain active in the solution and action on sulphur begins only on application in the soil. The plant nutrient composition and the kit of the present invention increase the germination rate in plants. Furthermore, it also increases plant yields. Still, furthermore, it also makes the plants resistant to pests and diseases. The example will now be described with the help of the following non- limiting examples.

Examples:

Example 1 :

The bio-sulphur mass (1500 kg) was water washed and was sun dried for a period of 26 days to reduce the pH to 2.7. The lumps of the dried bio-sulphur mass were pulverised to obtain aggregates with an average particle size 2 mm.

The acidophilic sulphur oxidizing bacteria, T. thiooxidans 226 litres (with

o

bacterial concentration of 1 x 10 per ml was admixed with a moisture retaining excipient i.e bentonite (150 kg) and the pulverized bio-sulphur mass aggregates in a rotary mixer to obtain a wet mass.

The granules thus prepared were then introduced to the soil in a farm plot of 1 hectare with a soil pH of 8.5. Water was sprayed immediately after introducing the granules to the soil and thereafter in order to maintain the moisture at 30 %. The pH of the soil was measured after 37 days and it was found out to be 7.2

Example 2:

The aggregates of the bio-sulphur mass (1500 Kg ) with a pH of 3.00 were obtained by the same process as provided in example 1.

These aggregates were introduced to the soil with a pH of 8.2 in another plot with of 1 hectare. A stock culture (300 litres) containing T. thiooxidans was sprayed on the farm within 3 hours from the introduction of the bio-sulphur mass aggregates by means of a spray pump. Water was sprayed to maintain moisture at 30 %. The pH of the soil was measured after a period of 30 days and it was found out to be 6.9.

Test Data

Test Example 1

Differences between Chemical Sulphur and the bio-sulphur mass

The physical and chemical properties of the inorganic elemental sulphur and the bio-sulphur mass were tested. The comparison of these properties is provided in Table 1. Table 1

Test Example 2:

The pH profile of the bio-sulphur mass employed in the plant nutrient release system of the present invention was studied for 37 days. The biosulphur mass was obtained from a bio-desulphurization plant near Shirdi, Maharashtra in India.After its isolation from the reactor, it was washed and 10 gm of the washed bio-sulphur mass with an initial pH of 7.76 was kept in a beaker at room temperature under observation.

The pH of the sample under observation was checked every alternate day over a period of 37 days using a pH meter. The gradual change in the pH of the sample as observed over a period of time is shown in Table 2 provided below. The normality of the acid produced in the sample over a period of time was also measured by a standard acid-base titration between a 1% solution of the sample and NaOH solution and using the formula grams/litre = Normality / Equivalent weight. The normality of the sample was thus calculated and it was found to be 0.002N after the stabilization of pH.Thus, it was found that the acid formed due to the inherent first group of sulphur oxidizing bacteria was not strong.

The graph provided in Figure 2 shows the pH profile of the bio-sulphur mass over a period of 37 days.

Field Study I

A field study of the pH of the soils in 46 plots was carried out. It was observed that 100% of the soils were alkaline, i.e. > pH 7 and required pH correction. The pH of the soil in these plots before the study is provided in Table 3 below.

Table 3: Field study of pH of 45 plots in Nagar District, Maharashtra in India.



The soil samples from 23 plots in Group A, were treated with a conventionally known composition comprising a combination of inorganic sulphur and sulphur oxidizing bacteria. For the same, 200 g of the soil samples in Group A were taken in 23 trays. Conventional inorganic sulphur and a culture of T. thiooxidans was mixed in a beaker and added to the 23 trays such that each tray contained 500 mg inorganic sulphur and 0.2 ml Thiobacillus thiooxidans culture. The Thiobacillus thiooxidans culture had a cell count of 10⁸ per ml. The composition was applied once and the pH was checked every alternate day using a pH meter. Moisture was kept constant at 30% using a spray.

For Group B, the similar procedure was repeated. 200g of soil samples from the 23 plots were taken in 23 trays. Biosulphur mass obtained from a bio- desulphurization plant near Shirdi was taken after washing and mixed with Thiobacillus thiooxidans in a beaker. This mixture was added to the 23 trays such that each tray contained 500 mg of the bio-sulphur mass and 0.2 ml Thiobacillus thiooxidans. The Thiobacillus thiooxidans had a cell count of 10⁸ per ml. The composition was applied once and the pH was checked every alternate day using a pH meter. Moisture was kept constant at 30% using a spray.

The average pH for 23 plots in each group during the study period is shown in Table 4 provided below.

Table 4

* Assuming reduction to pH 6.5= 100% reduction

BSM - Bio-sulphur mass

TT- Sulphur oxidizing bacteria, Thiobacillus Thiooxidans (Second group of Bacteria) l?¾ +SOB - Plant nutrient release System of the present Invention CS - Conventionally known elemental sulphur /Chemical sulphur

CS+TT - Prior art composition comprising chemical sulphur and Thiobacillus Thiooxidans

The comparative change in pH in the soils of plots from each of the Groups is shown in Figures 2,3 and 4

It can be seen ++from the graphs in Figures 2, 3 and 4 that the change in pH in case of the plots in Group B, treated with the plant nutrient release system of the present invention was not not only substantial but it was also quicker than the corresponding change in pH in the soils of plot in Group A (Control Group)

For example, from the Graph shown in Figure 3, it can be seen that the reduction of pH of soil from 8.53 to 8 was achieved in 15 days in Group B( wherein the plant nutrient release system of the present invention was used). While it took 25 days to achieve the same change in pH in Group A (Control Group).

In 15 days, the reduction in pH in case of Group B was 8.53 to 8 whereas in the same period, in Group A the change in pH was from 8.53 to 8.2.

From graph 4 in Figure 4, it can be seen that after 37 days, 63.5% of the pH correction was complete in case of plots in Group B whereas only 38.4% of the pH correction was complete ater 37 days in case of the plots in Group A.

On adding a trendline to the graphs, it can also be seen that the 100% completion of the pH correction would take 57 days in case of plots in Group B. While in case of plots in Group A, the time required for 100% pH correction would be 92 days.

The photographs of the plants in plots from Group A (control Group) and Group B are provided in Figures 5 and 6. It is clearly evident from these photographs that photosynthetic activity for Group B is better, thus improving the greening and resulting in better yield

Field Study II :

Impact of the proportion of Thiobacillus thiooxidans in the plant nutrient release system of the present invention on the rate of pH correction:

In this study, the soils in 4 different plots, Plot I, II, III, IV and V were treated with 5 diferent compositions with varying proportions of bio-sulphur and Thiobacillus thiooxidans.

The details of the compositions used for treating the soils in plots I to V are provided in Table 5 below:

Plot III 200 g soil + Bio-sulphur mass (500 mg) + 0.2 ml 37 days culture containing Thiobacillus Thiooxidans (l( /ml)

Plot IV 200 g soil + Bio-sulphur mass (500 mg) + 0.2 ml 37 days culture containing Thiobacillus Thiooxidans

(l(f/ml)

Plot V 200 g soil + Only bio-sulphur mass (500 mg) 37 days

(l( /ml)

The results from this study are provided in Table 6 provided below :

Table 6

21 7.75 7.87 7.95 8.1 8.11

23 7.72 7.8 7.88 8.03 8.05

25 7.66 7.73 7.81 7.98 8

27 7.58 7.67 7.75 7.93 7.96

29 7.52 7.6 7.7 7.9 7.91

31 7.47 7.54 7.65 7.89 7.89

33 7.34 7.48 7.59 7.83 7.85

35 7.32 7.41 7.52 7.79 7.8

37 7.24 7.34 7.48 7.75 7.77

From Graph 7 in Figure 7, it is concluded that the rate of microbial oxidation and hence the rate at which sulphates are made available to the plant/ soil is amended for pH can be controlled by varying the proportion of second group of sulphur oxidizing bacteria.

While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

Claims

Claims:

1. A plant nutrient composition comprising a bio-sulphur mass containing a first sulphur oxidizing bacteria and a second group of sulphur oxidizing bacteria.

2. A plant nutrient composition as claimed in claim 1, wherein the bio-sulphur mass is produced by the first group of oxidizing bacteria.

3. A plant nutrient composition as claimed in claim 1, wherein the oxidation state of the bio-sulphur mass is predominantly zero.

4. A plant nutrient composition as claimed in claim 1, wherein the pH of the bio- sulphur mass ranges between 2.5 and 8.5.

5. A plant nutrient composition as claimed in claim 1, wherein the first group of sulphur oxidizing bacteria is at least one selected from the group Thiobacillus thioparus, Thiobaccilus thiothrix, Thiomicrospirafrisi, Thioalkalibacter halophilus, Thioalk livibrio, Thioalkalispira and Thiobacillus novellus.

6. A plant nutrient composition as claimed in claim 1, wherein the first group of oxidizing bacteria exhibit optimum activity at pH ranging between 6 and 9.

7. A plant nutrient composition as claimed in claim 1, wherein the second group of oxidizing bacteria are acidophilic sulphur oxidizing bacteria.

8. A plant nutrient composition as claimed in claim 1 , wherein the second group of oxidizing bacteria is T.thiooxidans.

9. A plant nutrient composition as claimed in claim 1, wherein the second oxidizing bacteria exhibit optimal activity at pH ranging between 1 and 6.

10. A plant nutrient composition as claimed in claim 1 , further comprising at least one nutrient selected from the group consisting of N, K, Fe, Ni, Co, Al, Zn, Mo.

11. A plant nutrient composition as claimed in claim 1 , further comprising at least one excipient selected from the group consisting of bentonite, kaoline, gelatine, cellulose and xanthan gum.

12. A plant nutrient composition as claimed in claim 1, further comprising at least one mineral selected from the group consisting of rock phosphate and oxides, carbonates, acid addition salts of metals or elemental metals as such, said metals being selected from the group consisting of Zn, Ca and Mg, Fe, Bo.

13. A plant nutrient composition as claimed in claims 10 to 12, wherein the composition is in at least one form selected from the group consisting of granules, powder, and compressed blocks.

14. A process for preparing a plant nutrient composition as claimed in claims 1 to 13, said process comprising :

centrimging/filterpressing/settling the washed or unwashed bio-sulphur mass and optionally drying it;

15. A plant nutrient kit comprising a container comprising a bio-sulphur mass containing a first group of oxidizing bacteria and a container containing a culture of second group of sulphur oxidizing bacteria.

16. A plant nutrient kit as claimed in claim 15, wherein the bio-sulphur mass is produced by the first group of oxidizing bacteria.

17. A plant nutrient kit as claimed in claim 15, wherein the oxidation state of the bio-sulphur mass is predominantly Zero.

18. A plant nutrient kit as claimed in claim 15, wherein the pH of the bio- sulphur mass ranges between 2.5 and 8.5.

19. A plant nutrient kit as claimed in claim 15, wherein the first group of sulphur oxidizing bacteria is at least one selected from the group consisting of Thiobacillus thioparus, Thiobaccilus thiothrix, Thialkalibacter Halophilus, Thioalkalivibrio, Thioalkalispira, Thiomicrospirafrisi and Thiobacillus novellus.

20. A plant nutrient kit as claimed in claim 15, wherein the first group of oxidizing bacteria exhibit optimum activity at pH ranging between 6 and 9.

21. A plant nutrient kit as claimed in claim 15, wherein the second group of oxidizing bacteria are acidophilic sulphur oxidizing bacteria.

22. A plant nutrient kit as claimed in claim 15, wherein the second group of oxidizing bacteria is T.thiooxidans.

23. A plant nutrient kit as claimed in claim 15, wherein the second group of oxidizing bacteria exhibit optimal activity at pH ranging between 1 and 6.

24. A plant nutrient kit as claimed in claim 15, wherein the container containing bio-sulphur mass further comprises at least one nutrient selected from the group consisting of N, K, Fe, Ni, Co, Al, Zn, Mo.

25. A plant nutrient kit as claimed in claim 15, wherein the container containing bio-sulphur mass further comprises at least one mineral selected from the group consisting of rock phosphate and oxides, carbonates, acid addition salts of metals or elemental metals as such, said metals being selected from the group consisting of Zn, Ca and Mg, Fe, Bo.

26. A plant nutrient kit as claimed in claim 15, wherein the container containing bio-sulphur mass further comprises at least one excipient selected from the group consisting of bentonite, kaoline, gelatine, cellulose and xanthan gum.