DESC:
FIELD OF THE INVENTION
The present invention relates to a stable composition, suitable for plants, comprising a nitrogen containing nutrient(s) and a process for preparation thereof.

BACKGROUND OF THE INVENTION
Crop nutrients or fertilizers have been applied to the soil for several years. Nitrogen, along with potassium and phosphorous, is an essential nutrient for growth and development of plants. Urea continues to be the most widely used source of nitrogen containing fertilizer. It is a colourless, odourless organic compound having two amino group and a carbonyl functional group. It is highly soluble in water. Although most of the urea is used in a solid granular form, its use in the form of liquid also continues to occupy an important segment of the fertilizer market.
Urea, once applied to the soil, gets converted to ammonia by urease, an enzyme produced by endogenous microorganisms present in the soil. The ammonia in turn undergoes hydrolysis rapidly to form ammonium ions. These ammonium ions undergo the process of nitrification to form ammonium nitrate. These ammonium ions and / or ammonium nitrate are directly assimilated by plants for its use.
One of the major challenges faced while using solid urea is that some fraction of the nitrogen is lost after application before it is assimilated by plant. For instance, nitrogen is lost due to volatilization of ammonia to atmosphere, denitrification to gaseous nitrogen, and nitrate leaching.
Factors affecting the availability of the nitrogen from urea fertilizer for it to be assimilated by plant include fertilizer grain size, soil type, soil pH, moisture content of the soil, temperature as well as the application method. Smaller fertilizer grain sizes dissolve faster, releasing nitrogen faster than if larger granules are used. The greatest loss of effectiveness of urea fertilizer is through loss of ammonia if the urea remains on the surface of the soil. The breakdown of urea when combined with water and the soil enzyme urease includes release of ammonia gas. If the urea hasn't infiltrated into the soil through irrigation or been mechanically tilled into the soil, the ammonia and its nitrogen escape to the atmosphere with at least half of the nitrogen lost 24 hours after application. The loss of ammonia is much slower when the air temperature is lower.
Besides the application of the larger number of fertilizers, which are applied at higher rates and frequency, the farmers end up placing a large burden on the environment in terms of chemical excipients and adjuvants added to the soil or applied to the crops. Further, when formulated at high solids contents to maximize the total nitrogen value, these liquid fertilizers present their own stability problems. Notwithstanding these inherent inefficiencies and potential problems, liquid fertilizers based on such formulations continue to be an attractive way of applying nitrogen fertilizers to plants. In view of this scenario, there is a need to reduce the burden on the environment, reduce the amount of chemicals added to the soil and the crop, by judicious selection of excipients, which can improve stability and efficiency of the plant nutrients or the fertilizers, thus increasing availability of the nutrient to the plant for growth.
Many prior art references related to the field of fertilizers indicate the efforts for preparation of improved compositions by using variety of excipients and the processes.
Indian patent application 202341013684 relates to a nanocomposite slow-release nano fertilizer comprising binder, carrier, cross linker and fertilizer. The lignin is fortified with nitrogen derived from urea, bound with chitosan and crosslinked with citric acid to form a nanocomposite nano fertilizer. This nanocomposite nano fertilizer is produced by crosslinking mechanism due to the electrostatic attraction among the compounds.
Indian patent application 202121058946 relates to a method for manufacturing nanostructure composite used as nano fertilizer, manufactured from commercially available urea as a raw material. The method includes addition of water-soluble cellulosic material and capping polymeric material in aqueous solution of urea to get nanostructure composite material in aqueous colloid form.
Indian patent 420127 describes a process for preparation of nanofertilizer composition comprising fertilizer and synthetic polymers like polyethylenimines. The process also involves cross-linking agent selected from the group comprising of carboxylic acid polymer like polyacrylic acid.
Indian patent 400681 relates to method of manufacturing nano-nitrogen using urea or ammonia as a precursor for slow release in the form of solid, liquid or aerosol, wherein the nanofiber of oligosaccharide is attached with the respective nitrogen precursors. This invention also relates to a method of increasing surface area to volume size ratio by reducing the overall size of the fertilizer substances for growth of the plants.
Prior art references relate to application of nanotechnology or use of synthetic polymers, cross-linkers or fibrous material for formation of complex or composite with the nitrogen containing fertilizer, in order to prepare the liquid formulations and regulate the release of the nutrient over long period. However, none of the prior art references comment on the stability of the formulation, or impact of use of carriers or excipients for preventing agglomeration or flocculation of urea particles.
There is a need to develop alternate composition, which is stable and available for the plants and prepared using compatible excipients and a simple process. The present inventors have surprisingly developed an efficient nutrient composition and a process of preparation thereof which ameliorates the aforesaid shortcomings of the prior art.

OBJECTS OF THE INVENTION
The main objective of the present invention is to provide a stable composition, suitable for plant, comprising a nitrogen containing nutrient(s).
Another object of the invention is to provide such stable composition wherein the total nitrogen content ranges from about 1 to 20% by weight of the composition.
Yet another object of the invention is to provide a stable composition wherein the mean particle size of the composition may range from about 0.1 to 2000 nm.
Yet another object of the invention is to provide a stable nutrient composition wherein zeta potential ranges from about – 0.1 to -40 mV.
Yet another object of the invention is to provide a stable composition wherein the viscosity of the composition is in the range of about 1cps to about 25 cps.
Yet one more object of the invention is to provide such stable composition wherein the pH of the composition is in the range of 6 to 11.
Still another object of the invention is to provide a stable composition wherein the Brix value of the composition is in the range of 7 to 12 degrees Brix.
Yet another object of the invention is to provide a process for the preparation of such stable compositions.
Yet one more objective of the invention is to check the efficiency of a stable composition comprising a nitrogen containing nutrient for promoting plant growth and overall crop yield.

SUMMARY OF INVENTION
According to an aspect of the present invention, there is provided a stable nutrient composition for plant growth and enhancing overall crop yield.
According to another aspect of the present invention, there is provided a process of preparing a stable nutrient composition for plant.

DETAILED DESCRIPTION OF THE INVENTION
The following description is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.
Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the scope of the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, steps or components but does not preclude the presence or addition of one or more other features, steps, components or groups thereof.
The present invention relates to a stable composition, suitable for plants, comprising nitrogen containing nutrient and at least one excipient. The total nitrogen content of final product containing nutrient composition ranges from about 1 to 20% by weight of the composition and it is useful for providing nutrition to the plant, thus promoting plant growth and overall crop yield. Such compositions of the present invention are preferably in the form of liquid that optionally may be converted into a solid form such as powder or granules.
The present inventors have surprisingly found that the nutrient composition of the present invention with particular carriers or excipients in defined concentrations offered a stable composition, which could retain its particle size, without any flocculation, sedimentation, or agglomeration. The composition didn’t exhibit any turbidity, haziness, or precipitation during the study, as observed through constant Brix value over the shelf life; thus, indicating stability of the product, without any degradation of active and the carrier in the composition, when stored at various temperature and relative humidity conditions. Moreover, the process is simple as compared to existing prior arts and also the product is found to be comparable/at par with the marketed product, as observed during field trials.
The nitrogen containing nutrients may be selected from urea, ammonium chloride, ammonium sulphate, ammonium hydroxide, mono-ammonium phosphate, di-ammonium phosphate, ammonium nitrate, calcium ammonium phosphate, ammonium sulphate nitrate, or the combination thereof.
The nitrogen containing nutrient in the composition ranges from about 0.1 to 40% by weight of the composition, preferably from about 0.5 to 30%, more preferably from about 1 to 20% by weight of the composition.
In one more embodiment of the invention, the nitrogen containing nutrient may be urea, ammonium chloride, ammonium sulphate and di-ammonium phosphate, used either alone or in combination thereof to prepare the composition.
In one more embodiment of the invention, the nitrogen containing nutrient may be a mixture of urea with one more nitrogen containing nutrient.
The terminology ‘excipient’, as used within the scope of this invention, relates to the carrier used in the nutrient composition.
The excipient or carrier used in the composition of the present invention is selected from the group of amino acids, cellulose derivatives, natural gums, or the mixtures thereof.
Amino acid in the composition of the present invention is selected from glycine, L-lysine, L-alanine, L-arginine, L-histidine, L-methionine, L-proline, L-threonine, L-valine, their salts or the mixtures thereof.
Cellulose derivative in the composition of the present invention is selected from carboxy methyl cellulose (CMC), hydroxypropylmethyl cellulose (HPMC), hydroxypropyl cellulose (HPC), carboxymethylcellulose (CMC), sodium carboxymethylcellulose or the mixtures thereof.
Natural gum in the composition of the present invention is selected form guar gum, xanthan gum, acacia, locust bean gum or the mixtures thereof.
In an embodiment of the invention, the stable nutrient composition may be comprised of combination of excipients selected from the group of amino acids, cellulose derivatives, natural gums.
The excipient in the composition of the present invention is in the range of about 0.01% to about 20% by weight of the composition.
As per one more embodiment of the invention, the stable nutrient composition may further be comprised of surfactant in combination of excipient selected from ammonium lauryl sulfate, sodium lauryl sulfate, and sodium lauryl sarcosinate, sodium myreth sulfate, sodium pareth sulfate, sodium stearte, sodium lauryl sulfate, a-olefin sulfonate, ammonium laureth sulfate, Alkylbenzene Sulfonic Acid or combination thereof.
The invention also relates to a process for the preparation of composition comprising nitrogen containing nutrient and at least one excipient.
In one of the embodiments of the present invention, the process may be comprised of the below steps:
(a) dispersing and /or dissolving at least one nitrogen containing nutrient in water;
(b) dispersing and/or dissolving at least one excipient in water;
(c) mixing dispersion or solution of step (a) with the dispersion or solution of step (b);
(d) optionally continuing stirring the mixture for at least 15 minutes;
(e) optionally filtering the resultant mixture using a suitable filter;
(f) optionally providing heat treatment to the resultant mixture to obtain the nutrient composition.
According to one more embodiment of the present invention, the process may be comprised of the below steps:
(a) dispersing and / or dissolving at least one nitrogen containing nutrient in water;
(b) dispersing and/or dissolving at least one excipient in water;
(c) mixing dispersion or solution of step (a) with the dispersion or solution of step (b);
(d) add surfactant with continuous stirring the mixture for at least 15 minutes;
(e) optionally filtering the resultant mixture using a suitable filter;
(f) optionally providing heat treatment to the resultant mixture to obtain the nutrient composition.
The process, as described in the invention is economical, simple, environmentally safe and employs commonly used industrial equipment. The process does not make use of any hazardous solvent or excipient.
As per one embodiment, the nutrient composition may be prepared by making aqueous solution of 0.01 to 40% w/v of the nitrogen containing nutrient and mixing it for 15 to 60 minutes, by stirring with the aqueous solution of the excipient.
According to one important embodiment, the nitrogen content of the final product containing nutrient composition is about 1 to 20% by weight of the resulting liquid composition.
The nutrient composition is evaluated by measuring nitrogen content, zeta potential, pH, Brix values and the particle size. The composition is also evaluated for its efficiency during field trial by checking straw yield, grain yield, number of effective tillers, dry matter production per hill, number of panicles and panicle length.
The nutrient composition of the present invention is evaluated for stability through measurement of zeta potential, to understand the behavior of the colloidal particles of nutrient in the solution and/or dispersion system.
Zeta potential is a parameter that measures the electrochemical equilibrium at the particle-liquid interface. It measures the magnitude of electrostatic repulsion/attraction between particles and thus, it has become one of the fundamental parameters known to affect stability of colloidal particles. The behaviour of aqueous dispersions between particles and liquid is especially sensitive to the ionic and electrical structure of the interface.
The nutrient composition, as described herein exhibits the zeta potential ranging from -0.1 mV to -40 mV.
The Brix value for the composition of the invention indicates the total solids dissolved in the liquid composition. The measurement of Brix value over the period of shelf life of a liquid composition indicates if the value remains constant and the composition does not undergo any phenomenon like precipitating out, coagulation or flocculation of the colloidal particles solubilized/ suspended in the system. The constant value also indicates that the active and the carrier do not get degraded in the formulation system in various conditions of temperature and humidity, during storage or shelf life, thus indicating a stable composition.
The Brix value was observed to be in the range of 7 to 12 degrees Brix, when checked using refractometer over a period of 3 months in various conditions of temperature and relative humidity.
The particle size distribution of the composition was measured on the day of preparation and over the shelf-life of 6 months, using DLS (Dynamic Light Scattering) equipment.
Dynamic light scattering, sometimes referred to as Quasi Elastic Light Scattering (QELS), is a non-invasive, well-established technique for measuring the size and size distribution of molecules and particles typically in the submicron region. Typical applications of dynamic light scattering are the characterization of particles, emulsions or molecules which have been dispersed or dissolved in a liquid. The Brownian motion of particles or molecules in suspension causes laser light to be scattered at different intensities. Analysis of these intensity fluctuations yields the velocity of the Brownian motion and hence the particle size using the Stokes-Einstein relationship.
The mean particle size of the nutrient composition, as described herein may range from about 0.1nm to 2000 nm. According to one preferred embodiment, the mean particle size of the product may range between 0.5 nm to 1000 nm. As per the most preferred embodiment, the mean particle size of the composition may range between 0.1 nm to 250 nm.
The nutrient composition is evaluated through field trial selecting suitable crop and the efficiency is compared with the reference product and found to be useful for enhancing plant growth and overall crop yield.
The following examples are given for purely illustrative and non-limiting purposes of the present invention.

EXAMPLES:
The invention is now illustrated with non-limiting examples.
Materials: The urea used in the present invention is a white colored, free flowing product purchased from the local suppliers like Labogen fine Chemicals and Metpolychem. Further, ammonium chloride, ammonium sulphate and di-ammonium phosphate used in the present invention are purchased from Merck.

EXAMPLE 1: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of Urea (30% w/w) containing 20% by weight of nitrogen was prepared. The aqueous solution of 2.4% w/w L-lysine hydrochloride was prepared separately. Both the solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min to get a liquid nutrient composition.
The particle size distribution and the zeta potential of the nutrient composition, as prepared by Example 1 (Batch-1) was checked and tabulated in Table 1. The composition was observed at ambient condition over 18 days for both the parameters and the outcome was tabulated in Table 2.

Table 01: Particle size distribution and Zeta potential of the nutrient composition
Nutrient Composition Size distribution Zeta Potential (mV)
D(i10) D(i50) D(i90) D(i95) D(i99)
Example 1 (Batch-1) 0.616 0.867 795 1140 1940 -0.864

Table 02: Stability study of Nutrient composition Example 1
Time point Peak 1 Peak 2 Zeta Potential (mV)
Size
(d. nm) % Intensity Size
(d. nm) % Intensity
Example 1 (Batch-1) Initial 0.76 65.30% 671.8 34.70% -8.55
Example 1 (Batch-1) Day 18 0.79 68.10% 1022 31.90% -11.2

Three more batches of Example 1 (Batch 2, 3 and 4) containing amino acid (L-lysine hydrochloride) were studied for stability over 3 months at various conditions of temperature and humidity. The composition was evaluated for parameters such as pH, Brix value, nitrogen content, particle size and zeta potential. The results are tabulated below in Table 03 and 04.

Table 03: Stability study at 30°C /75% for the composition prepared as per Example 01
Product Name Test Parameter Initial 1 M 3 M
(30°C/ 75%) (30°C/ 75%)
Example 1 (Batch-2) Chemical Nitrogen assay (%w/w) 4.29 4.31 4.2
Brix 10.9 10.8 10.9
pH 7.21 7.25 7.32
Particle size by DLS (nm) Peak 1 476.4 0.796 379.8
% Intensity 62.2 89.5 100
Zeta Potential + (mV) -9.75 -4.18 -9.1
Example 1 (Batch-3) Chemical Nitrogen assay (%w/w) 4.34 4.28 3.89
Brix 10.9 10.8 11
pH 7.18 7.24 7.42
Particle size by DLS (nm) Peak 1 188.7 0.6213 0.913
% Intensity 90.8 100 94.8
Zeta Potential + (mV) -7 -4 -11.3
Example 1 (Batch-4) Chemical Nitrogen assay (%w/w) 4.3 4.31 4.08
Brix 10.9 10.9 10.9
pH 7.21 7.84 7.88
Particle size by DLS (nm) Peak 1 136.8 0.7292 220.2
% Intensity 92.8 85.4 100
Zeta Potential + (mV) -6.29 -7.76 -12.1

Table 04: Stability study at 40°C /75% for the composition prepared as per Example 01
Product Name Test Parameter Initial 1 M 2 M 3 M
(40°C/75%) (40°C /75%) (40°C /75%)
Example 1 (Batch-2) Chemical Nitrogen assay (%w/w) 4.29 4.23 4.09 4.03
Brix 10.90 10.90 10.90 11.00
pH 7.21 7.49 7.67 7.84
Particle size by DLS (nm) Peak 1 476.40 0.82 1.29 0.65
% Intensity 62.20 94.40 100.00 100.00
Zeta Potential + (mV) -9.75 -3.34 -1.04 -4.85
Example 1 (Batch-3) Chemical Nitrogen assay (%w/w) 4.34 4.34 4.10 4.08
Brix 10.90 10.90 11.00 10.90
pH 7.18 7.48 7.61 7.43
Particle size by DLS (nm) Peak 1 188.70 295.30 0.77 620.40
% Intensity 90.80 100.00 81.90 100.00
Zeta Potential + (mV) -7.00 -3.34 -8.95 -6.67
Example 1 (Batch-4) Chemical Nitrogen assay (%w/w) 4.30 4.24 4.16 3.99
Brix 10.90 10.90 10.90 10.90
pH 7.21 7.49 7.60 7.82
Particle size by DLS (nm) Peak 1 136.80 0.73 0.70 0.91
% Intensity 92.80 80.00 98.00 52.20
Zeta Potential + (mV) -6.29 -4.20 -5.23 -5.64

The composition comprising L-lysine hydrochloride as a carrier was found to be stable during stability study, as observed through various physical and chemical parameters, such as Brix value, pH, particle size, Nitrogen content and zeta potential. The Brix value and Nitrogen content was constant, and the particle size of the composition ranged from 0.1 to 2000 nm. The composition was found to be stable over the shelf life under both storage conditions.

EXAMPLE 02: Nutrient composition containing 6% by weight of nitrogen
Aqueous solution of Urea (30% w/w) was prepared containing 20% by weight of nitrogen. The aqueous solution of 3.0% w/w L-lysine hydrochloride was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 03: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of Urea (30% w/w) was prepared containing 20% by weight of nitrogen. The aqueous solution of 2.5% w/w sodium carboxy methyl cellulose was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 04: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of Urea (30% w/w) was prepared containing 20% by weight of nitrogen. The aqueous solution of 0.014% w/w of guar gum was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

Table 05: Particle size distribution and Zeta potential of nutrient composition of Example 04
Nutrient composition Size distribution Zeta Potential (mV)
D(i10) D(i50) D(i90) D(i95) D(i99)
Example 4 109 214 338 379 448 -8.55

Table 06: Stability study of Nutrient composition Example 04
Time point Peak 1 Peak 2 Zeta Potential (mV)
Size
(d. nm) % Intensity Size
(d. nm) % Intensity
Example 4 Initial 234.9 90.90% 35.61 9.10% -0.86
Example 4 Day 18 238 94.60% 26.34 5.40% -4.37

Particle size and zeta potential of the nutrient composition described above in Example 1 and Example 4 were determined at initial time point and after day 18, to check the stability. It was observed that the composition, comprising nutrient and the excipient exhibits the similar particle size distribution, without any considerable change, over a period of 18 days. This indicates that there is no agglomeration/flocculation or sedimentation of particles in the composition prepared as per Example 1 and Example 4.

EXAMPLE 05: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of Urea (30% w/w) and aqueous solution of 0.014% w/w of guar gum was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.
The stability study for nutrient composition kept in transparent glass bottle was carried out as per ICH guidelines at controlled conditions of temperature and relative humidity, selected as 40°C /75% and 30°C /75% over a period of 6 months.

Table 07: Stability study at 40°C /75% for the composition prepared as per Example 05
Product name Test Parameters Initial 1 M 2 M 3 M 6 M
(40°C /75%) (40°C /75%) (40°C /75%) (40°C /75%)
Example 5 (Batch 1) Chemical Nitrogen assay (%w/w) 4.37 4.49 4.66 4.19 4.36
Brix (°Bx) 9.3 9.6 9.4 9.5 9.4
pH 8.24 8.86 9.32 9.37 8.73
Particle size by DLS(nm) Peak 1 258.5 159.7 122.4 143.6 182.7
% Intensity 83.8 91.4 80.3 100 75
Zeta Potential (mV) -8.4 -4.48 -13.7 -21.7 -13.7
Example 5
(Batch 2)



Chemical Nitrogen assay (%w/w) 4.29 4.41 4.45 4.26 4.4
Brix (°Bx) 9.1 9.5 9.4 9.9 9.4
pH 8.42 8.98 9.29 9.44 8.72
Particle size by DLS Peak 1 242.3 261.1 43.56 147.8 217.3
(nm) % Intensity 98.1 77.9 77.1 100 83.4
Zeta Potential (mV) -0.895 0.459 -8.61 -26.4 -15.3
Example 5 (Batch 3) Chemical Nitrogen assay(%w/w) 4.28 4.47 4.41 4.27 4.4
Brix (°Bx) 9.1 9.6 9.4 9.4 9.5
pH 8.36 8.84 9.32 9.35 8.73
Particle size by DLS Peak 1 261 321 83.53 181 234.3
(nm) % Intensity 96.1 85.7 100 72.3 70.6
Zeta Potential (mV) -5.09 -8.19 -3.25 -21.7 -11.4

Table 08: Outcome of the stability study at 30°C /75% for the composition prepared as per Example 05
Product name Test Parameters Initial 1M 3 M 6 M
(30°C /75%) (30°C /75%) (30°C /75%)
Example 5-Batch 1 Chemical Nitrogen assay (%w/w) 4.37 4.47 4.44 4.19
Brix (°Bx) 9.3 9.5 9.5 9.6
pH 8.24 9.02 9.28 9.41
Particle size by DLS
(nm) Peak 1 258.5 429.1 79.97 60.49
% Intensity 83.8 62.8 79.7 97
Zeta Potential (mV) -8.4 -12 -5.14 -9.31
Example 5- Batch 2 Chemical Nitrogen assay (%w/w) 4.29 4.46 4.43 4.39
Brix (°Bx) 9.1 9.6 9.5 9.5
pH 8.42 8.58 9.23 9.34
Particle size by DLS
(nm) Peak 1 242.3 183.1 98.69 547.1
% Intensity 98.1 79.6 100 100
Zeta Potential (mV) -0.895 -20.6 -25.1 -11.1
Example 5-Batch 3 Chemical Nitrogen assay(%w/w) 4.28 4.5 4.4 4.28
Brix (°Bx) 9.1 9.5 9.5 9.7
pH 8.36 8.42 9.1 9.34
Particle size by DLS
(nm) Peak 1 261 463.1 65.69 504.1
% Intensity 96.1 92.2 93.2 100
Zeta Potential (mV) -5.09 -12.1 -13.9 -12.9

The nitrogen content of nutrient composition is measured using distillation and digestion method and it was found to be stable, as compared to initial value, over a period of 6 months.
The Brix value of the composition which measures the amount of dissolved solids in the composition using refractometer, was found to be constant during the stability study, thus indicating there is no degradation of the dissolved solids or even the precipitation out of the system over a period of 6 months.
The pH of the nutrient composition was measured using pH meter at room temperature and it is found to be in the range from 6 to 11.
The mean particle size of the nutrient composition was found to be in the range between 0.5 nm to 1000 nm. The composition didn’t exhibit any sedimentation or aggregation/flocculation and was found to be clear and stable. The data for nitrogen content, pH and zeta potential was also found to confirm the stability of the nutrient composition. Thus the composition comprising nutrient for use in plants was found to be stable over a shelf life of 6 months under various storage conditions

EXAMPLE 06: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of urea is prepared by dissolving 8.6 gm urea in 20 gm of water (making 30% w/v urea solution), continue stirring for 15 minutes 0.01 gm of guar gum is dissolved in 71.39 gm water, continue stirring for 15 minutes. The above solutions are mixed under stirring at 50°C and add 5 gm Linear Alkylbenzene Sulfonic Acid under continue stirring for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 07: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of ammonium sulphate (32% w/w) containing 10% by weight of nitrogen and aqueous solution of 0.024% w/w of guar gum was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 08: Nutrient composition containing 4% by weight of nitrogen
Aqueous solution of ammonium chloride (28% w/w) containing 20% by weight of nitrogen and aqueous solution of 0.014% w/w of guar gum was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 09: Nutrient composition containing 8% by weight of nitrogen
Aqueous solution of diammonium phosphate (51% w/v) containing 20% by weight of nitrogen and aqueous solution of 0.01% w/v of guar gum was prepared separately. Both solutions were mixed under stirring at 40°C to 60°C for 15 minutes. The resultant mixture was filtered and then pasteurized at 70°C to 90°C for 5 to 10 min.

EXAMPLE 10: Experimental Information about field trial using the nutrient composition of the invention
Location Main Rice Research Station, AAU, Nawagam
Design Randomised Block Design (RBD) with factorial concept
Crop Rice
Varieties Gurjari
Plot size 20 x 15 cm
Method of sowing Transplanting
Seed rate 25 kg/ha
Treatment details Factor A: Comparison of effect of composition of the invention (sample as per Example 5) vs reference product
N1: Sample is prepared as per Example 05
N2: Reference sample
Factor B: Comparison of effect of various concentrations of sample as per Example 05 vs reference product
F1: 0 ml/lit water
F2: 2 ml/lit water
F3: 4 ml/lit water
F4: 6 ml/lit water
F5: 8 ml/lit water
*N2 is the reference Urea product available in market which is Liquid nano Urea product containing 4% Nitrogen as encapsulated nitrogen analogues or forms embedded on an organic matrix.
** In both Factor A and B, the treatment was using foliar spray as a mode of use of the product. Thus there is no difference with the mode of application. But the statistical treatment is different. Factor A indicates the treatment of both the reference and sample and its comparison. While factor B is calculated as the average of reference and sample products, applied in different dilutions, as shown in the above table

Table 09: Grain and straw yield obtained by using composition of the invention (Example 05) during the field trial
Treatment Grain Yield/Plant (g) Straw yield/Plant (g) Grain yield (kg/ha) Straw yield (kg/ha)
Factor A- Comparison of effect of composition of the invention vs reference product
N1- Sample is prepared as per Example 05 22.48 28.74 6272 6653
N2- Reference Product 22.17 28.4 6228 6767
Factor B - Comparison of effect of various concentrations of sample (composition of the invention) as per Example 05 vs reference product
F1 – 0mL/L water 18.69 23.2 5448 5796
F2 – 2mL/L water 24.55 31.5 6582 7093
F3 – 4mL/L water 22.9 29.47 6508 7000
F4 – 6mL/L water 23.05 28.79 6359 6793
F5 – 8mL/L water 22.46 29.91 6351 6868

The result of Table 09 indicates that the yield of rice was significantly affected due to the foliar spray treatments (Factor B). The application of foliar spray treatment F2 (2mL/L water) recorded significantly higher grain yield per plant (24.55 g), straw yield per plant (31.50 g), grain yield (6582 kg/ha) and straw yield (7093 kg/ha) of the rice than the other treatments followed by treatments F3 (4mL/L water), F4 (6mL/L water) and F5 (8mL/L water) with respect to grain yield and straw yield. The composition of the invention was found to be at par with the reference product. Thus the nutrient composition of the invention, was found to be effective and useful considering the yield attributes and yield of rice, in comparison with the reference product.

Table 10: Yield attributes of Rice through different parameters
Treatment No of effective tiller/plant Dry matter production/hill(g) Grain /panicles Panicle length (cm) Test weight (g)
Factor A- Comparison of effect of Composition of the Invention (sample as per Example 05) vs reference product
N1- Sample 1 as per example 05 11.53 12.6 145 22.18 29.66

N2- Reference product 11.81 11.65 148 21.57 29.61

Factor B - Comparison of effect of various concentrations of the composition of the invention (sample as per Example 05) vs reference product
F1 – 0mL/L water 9.31 8.49 128 21.83 29.8
F2 – 2mL/L water 11.42 12.78 153 22.07 29.77
F3 – 4mL/L water 12.24 13.15 151 21.88 29.78
F4 – 6mL/L water 12.86 14.26 152 21.86 29.60
F5 – 8mL/L water 12.74 11.96 151 21.74 29.22

Application of foliar spray of liquid urea treatments (Factor A) was found non-significant with respect to number of effective tillers per hill and dry matter production per hill. The result on number of effective tillers per hill at harvest and dry matter production per hill was influenced by foliar spray treatments (Factor B). Treatment F4 (6mL/L water) recorded significantly higher number of effective tillers per hill (12.86) and dry matter production per hill (14.26 g) which was followed by treatments F3 (4mL/L water), F2 (2mL/L water) and F5 (8mL/L water). (From table 10)
The result of Table 10 indicates that the effect of different Liquid urea treatments (Factor A) showed non-significant influence on number of grains per panicles; however, the result on number of grains per panicle was influenced by foliar spray treatments (Factor B). Treatment F2 (2mL/L water) recorded significantly higher number of grains per panicle (153) than the other treatment and it was followed by treatments F3 (4mL/L water), F4 (6mL/L water) and F5 (8mL/L water). The Liquid urea treatment N2 exhibited significantly higher panicle length (22.18 cm) than the other treatment. The composition of the invention was found to be at par with the reference product. Thus the nutrient composition of the invention was found to be effective for enhancing yield of Rice, as observed during the field trial.
The nutrient composition of the invention may be comprised of nitrogen containing nutrient, selected from urea, ammonium chloride, ammonium sulphate, di-ammonium phosphate or the combination thereof. The nutrient composition may be comprised of at least one excipient, and the composition is prepared by a simple process and using commonly available industrial equipment. The nutrient composition is stable over a shelf life of 6 months under various storage conditions. The composition is comprised of about 1 to 20% by weight of nitrogen content, and it is useful for promoting plant growth and overall crop yield including straw yield, grain yield, number of effective tillers, dry matter production per hill, number of panicles and panicle length.
It is to be understood that the present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such modifications, changes, adaptations are intended to be within the scope of the present invention.
,CLAIMS:
1. A stable nutrient composition for plant growth and enhancing overall crop yield comprising:
0.1 to 40% by weight of a nitrogen containing nutrient(s); and
0.01 to 20% by weight of at least one excipient.

2. The stable nutrient composition as claimed in claim 1 wherein the nitrogen containing nutrient is selected from urea, ammonium chloride, ammonium sulphate, ammonium hydroxide, mono-ammonium phosphate, di-ammonium phosphate, ammonium nitrate, calcium ammonium phosphate, ammonium sulphate nitrate, or the combination thereof.

3. The stable nutrient composition as claimed in claim 2, wherein the nitrogen containing nutrient is selected from urea, ammonium chloride, ammonium sulphate and di-ammonium phosphate.

4. The stable nutrient composition as claimed in claim 1, wherein the excipient is selected from amino acids or salts thereof, cellulose derivatives, natural gums, or the mixtures thereof.

5. The stable nutrient composition as claimed in claim 4, wherein excipient is selected from glycine, L-lysine, L-alanine, L-arginine, L-histidine, L-methionine, L-proline, L-threonine, L-valine, or salts thereof; carboxy methyl cellulose (CMC), hydroxypropylmethyl cellulose (HPMC), hydroxypropyl cellulose (HPC), carboxymethylcellulose (CMC), sodium carboxymethylcellulose, guar gum, xanthan gum, acacia, locust bean gum or the mixtures thereof.

6. The stable nutrient composition as claimed in claim 5, wherein the excipient is L-lysine hydrochloride.

7. The stable nutrient composition as claimed in claim 5, wherein the excipient is sodium carboxymethylcellulose.

8. The stable nutrient composition as claimed in claim 5, wherein the excipient is guar gum.

9. The stable nutrient composition as claimed in any one of the preceding claims further comprising a surfactant selected from ammonium lauryl sulfate, sodium lauryl sulfate, and sodium lauryl sarcosinate, sodium myreth sulfate, sodium pareth sulfate, sodium stearte, sodium lauryl sulfate, a-olefin sulfonate, ammonium laureth sulfate, Alkylbenzene Sulfonic Acid or combination thereof.

10. The stable nutrient composition as claimed in any one of the preceding claims wherein:
(i) Mean particle size of the said composition ranges from 0.1 to 2000 nm;
(ii) Zeta potential of the said composition ranges from – 0.1 to -40 mV;
(iii) Viscosity of the said composition ranges from 1cps to 25 cps;
(iv) pH of the said composition ranges from 6 to 11; and
(v) Brix value of the said composition ranges from 7 to 12 degrees Brix.

11. A process of preparing a stable nutrient composition for plant comprising the steps of:
a) dispersing and/or dissolving at least one nitrogen containing nutrient in water;
b) dispersing and/or dissolving at least one excipient in water;
c) mixing dispersion or solution of step a) with the dispersion or solution of step b) with continuing stirring for at least 15 minutes; followed by filtering the resultant mixture using a suitable filter;
d) optionally providing heat treatment to the resultant mixture to obtain the nutrient composition.

12. The process as claimed in claim 11, wherein the said process comprises the optional step of adding surfactant after step (c).