DESC:Technical filed:
The present invention relates to Lignosulfonate complexes of water soluble fertilizers that provides complete and sustainable nutrient supply to crops to get high yield and quality of agriculture produce. The present invention further relates to process for complexation of water soluble fertilizers with naturally occurred lignosulfonates. The present invention further relates to method of providing sustainable nutrient supply to crops by providing lignosulfonate complexes of water soluble fertilizers, to improve the yield and quality of the produce.

Background and prior art:
Synthetic chemical inorganic fertilizers such as ammonium phosphates, ammonium nitrates, Potassium nitrates, potassium chlorides, potassium sulphates; methods of manufacturing these inorganic fertilizers and methods of processing these fertilizers are well reported in the prior art. One of the primary problems encountered when handling, transporting and storing of these fertilizers is the fact that the fertilizers tend to lump due to crystallization. US Patents. Nos. 3,112,343, 4, 160,782 and 4,204,053 disclose various processes for the treatment of these fertilizers with additives such as formaldehyde in an effort to eliminate the crystallization problems. US4587358 discloses a fertilizer composition which employs lignosulphonates as an additive to improve anticaking properties.

Lignosulfonates are non- hazardous natural organic compounds commonly used for commodities like Coal, briquettes, ceramics and production of plywood. Lignosulfonates used in various industries as binder, dispersing agent, emulsifier and water reducing agent with multifunctional application in different industries and agriculture.
US 4846871 and US5114458 reports lignosulfonate treated fertilizer particles that results in harder particles less susceptible to breakage and to provide anti-caking and anti-dusting properties. The lignosulfonate treated fertilizer is prepared by a process which comprise heating the homogeneous mixture of the fertilizer and lignosulfonate before reducing the size of the particles. However, the product thus obtained comprises particle mixture of fertilizer and lignosulfonate that reduces the caking and dusting of the fertilizer. These prior arts do not discloses the effect of lignosulfonate treated fertilizer in improving the yield and quality of the produce in the fields.

J. N. Meier, et al reported the Effects of lignosulfonate-fertiliser mixture on soil respiration and nitrogen dynamics. This article concludes that the addition of LS initially increases a small proportion of CO2 evolution; slightly decreases urea hydrolysis; reduces the proportion of volatilization of added Nitrogen and thus can increase nitrogen availability.
However, none of the above prior arts describes complexation of water soluble fertilizers with naturally occurred lignosulfonates; thereby providing complete and sustainable nutrient supply to crops to get high yield and quality of agriculture produce.

Objectives of the present invention:
Accordingly, it is an objective of the present invention to provide lignosulfonate complexes of water soluble fertilizers.
It is another objective of the present invention to provide a process for preparation of lignosulfonate complexes of water soluble fertilizers.
It is yet another objective of the present invention to provide method of providing sustainable nutrient supply to crops which method comprising providing to the crops in effective amounts of the lignosulfonate complexes of water soluble fertilizers to improve the yield and quality of the produce.

Summary of the invention:
In line with the above objective, the present invention provides lignosulfonate complexes of water soluble fertilizers and process for preparation thereof.
In an aspect, the water soluble N, P, K fertilisers are selected from the group consisting of urea, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate, potassium chloride, ammonium nitrates, potassiun nitrates, potassium chlorides, potassium sulfates, potassium phosphate or combinations thereof.
Specific lignin sulfonate salts are included in the list by the OMRI-Organic Materials Review Institute. However, the Lignosulfonate typically used in the present invention are selected from the group consisting of sodium lignates, alkaline metal lignates, ammonium lignates, calcium lignates, potassium lignates or mixtures thereof.

Accordingly, in another aspect, the invention provides a process for preparation of lignosulfonate complex of water soluble fertilizers which process comprises;
a) Activating the carbon molecules of lignosulfonate by treating with Phosphoric acid at ambient temperature;
b) Slowly adding 100 % water soluble Nitrogen source at 30°C under continuous stirring to complete the reaction;
c) Slowly adding 100 % water soluble potassium source at 30°C under continuous stirring to complete the reaction; and
d) Slowly adding 100 % water soluble Phosphorous source at 30°C under continuous stirring to obtain lignosulfonate complex of N, P, K fertiliser.

Detailed description of the invention:
The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.
In accordance with the above objectives, the present invention provides lignosulfonate complexes of water soluble fertilizers.
In another embodiment, the invention provides a process for preparation of lignosulfonate complexes of water soluble fertilizers.
The functional groups in the lignosulfonates that can be complexed with water soluble fertilisers may be formed by activating the lignosulfonate compounds by treating with various acids like Phosphoric acids, Nitric acids, Hydrochloric acids, Sulfuric acids or by treating with various alkaline solutions like Potassium hydroxide, ammonium hydroxide, and Ammonium nitrates etc. or optionally with addition of a chelating agent. The activation of these organic molecules takes place by destruction of the metal complexes or of the inter-functional bonds of the lignosulfonate salts thereby release at least 10% of free complexing functional groups, which will react with the fertilisers in the subsequent step.

According to the present invention, "complexing functional groups' means any functional group that is able to form complexes with metals. These complexing functional groups are carboxyl, phenol and hydroxyl groups, for example. The number or the proportion of free complexing functional groups can be measured by various techniques that are well known by a person skilled in the art, for example by potentiometry or by gravimetry.

For example, the carboxyl complexing functional groups can be analysed by potentiometry, which makes it possible to determine, for example, the residual free acidity of organic compounds in solution corresponding to the acidity titratable with sodium hydroxide up to the pH of the equivalent point. It is obtained by plotting the titration curve of said organic Solution with a titrated Solution of sodium hydroxide and determining, from this curve, the equivalent volume of titrant solution. This method is notably described by Dr. William Horwitz and Dr. George Latimer, in “The 18th Edition, Revision 3, Official Methods of Analysis (AOAC), 2007, Jr. Editors'.

The activated functional groups in lignosulfonats such as carboxylic acids when subjected to complexation can be cross linked or chelated with Potassium ions, and or Nitrogenous compounds, and or phosphate ions, and or not limited to N,P,K based compounds, as individual and or with combination of other cationic molecules like Zinc, Magnesium, Manganese, Iron, Boron, Molybdenum etc.
Due to strong bonding of lignosulfonates with Nitrogen molecules, the prevention of nitrogen degradation in the soil compared with normal nitrogen based compounds is observed.

In an embodiment, the present invention provides complexation of lignosulfonates with specific ratio of 0.01% to 99.99 % Nitrogenous fertilizers like urea, liquid ammonia and or saturated solutions of nitric acid and or saturated solutions of Ammonium nitrate, ammonium chloride, mono ammonium phosphate etc., as individual and their combinations.

In another embodiment the present invention provides complexation of lignosulfonates in a specific ratio of 0.01% to 99.99% with phosphate fertilizers like Phosphoric acid and or saturated solutions of Mono Ammonium Phosphate and or, Mono Potassium Phosphate with various proportions of phosphate containing compounds as individual and their combinations
The present invention provides complexation of lignosulfonates in a specific ratio of 0.01% to 99.99% with Potassium fertilizers like saturated solutions of Potassium Hydroxide and or potassium sulphate and other various portions of potassium containing compounds as individual and their combinations.

However, in a preferred embodiment, the invention provides lignosulfonate complexes of N, P, K water soluble fertilisers.
Accordingly, in one preferred embodiment, the process for preparation of lignosulfonate complex of N, P, K water soluble fertilizers which process comprises;
a) Activating the carbon molecules of lignosulfonate by treating with Phosphoric acid at ambient temperature;
b) Slowly adding 100 % water soluble Nitrogen source at 30°C under continuous stirring to complete the reaction;
c) Slowly adding 100 % water soluble potassium source at 30°C under continuous stirring to complete the reaction;
d) Slowly adding 100 % water soluble Phosphorous source at 30°C under continuous stirring to obtain lignosulfonate complex of N, P, K fertiliser.

In an aspect, the water soluble N, P, K fertilisers are selected from the group consisting of urea, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate, potassium chloride, ammonium nitrates, potassiun nitrates, potassium chlorides, potassium sulfates, potassium phosphate or combinations thereof.
More specifically, the water soluble source of potassium is selected from the group consisting of ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, potassium phosphate, di-ammonium phosphate.
The water soluble source of phosphate is selected from the group consisting of nitrogen-potassium-phosphorus granulates, potassium phosphate, potassium chloride, potassiun nitrates, potassium sulfates, or combinations thereof.
The water soluble source of nitrogen is selected from the group consisting of urea, ammonium nitrates, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate potassiun nitrates, or combinations thereof.

In a preferred embodiment, the water soluble fertilisers are the combination of N, P, K fertilizers.

Lignosulfonate are typically selected from the group consisting of sodium lignates, alkaline metal lignates, ammonium lignates, calcium lignates, potassium lignates or mixtures thereof.

In a further embodiment, the invention provides the composition of lignosulfonate complex of water soluble fertilisers.

In a preferred embodiment, the water soluble fertilisers are the combination of N, P, K fertilizers. Accordingly, the lignosulfonate complex composition of the present invention comprises;
a) Lignosulfonate in an amount of 10 to 25%;
b) Water soluble source of Phosphate in an amount of 20 to 30%;
c) Water soluble source of Potassium in an amount of 8 to 12%; and
d) Water soluble source of nitrogen in an amount of 20 to 30%.

Accordingly, the water soluble N, P, K fertilisers are selected from the group consisting of urea, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate, potassium chloride, ammonium nitrates, potassiun nitrates, potassium chlorides, potassium sulfates, potassium phosphate or combinations thereof.

The lignosulfonate complex of the water soluble N, P, K fertilisers can be made into compositions optionally using suitable carriers such as suspending agent; gammacacia and other carriers.
Accordingly, in one preferred embodiment, the composition of lignosulfonate complex of N, P, K fertilizers which comprises;
a) Lignosulfonate in an amount of 10 to 25%;
b) Water soluble source of Phosphate in an amount of 20 to 30%;
c) Water soluble source of Potassium in an amount of 8 to 12%;
d) Water soluble source of nitrogen in an amount of 20 to 30%
e) suspending agent(s) in an amount of 2 to 5%; and
f) gammacacia in an amount of 30 to 60%.
In yet another embodiment, the present invention provides method of providing sustainable nutrient supply to crops which method comprising providing to the crops in effective amounts of the lignosulfonate complexes of water soluble fertilizers according to the present invention, to improve the yield and quality of the produce.

In yet another embodiment, field trails have been conducted on soya bean crop and Green gram crop using N-P-K Lignosulfonate based nutrition product -20-20-20 (composition of example 1) and compared the same with Farmer practice, as described under example 4.
As is evident from the results of this example, the fertigation with lignosulfonate complex of NPK fertilizer increases the plant height, pod length and number of pods/plant over conventional farmer’s practice. The soybean grain yield was increased by 28.9% with the use of Lignosulfonate C-N-P solution over farmers’ practice.
Similarly, in Green gram cropping system, the fertigation with lignosulfonate complex of NPK fertilizer gave higher seedling establishment, number of pods/plant, pod length, number of grains/pod and test weight than farmers practice. In addition, the green gram yield was increased by 47.1% with the use of Lignosulfonate C-N-P solution over farmers’ practice.

The following examples are presented to further explain the invention with experimental conditions, which are purely illustrative and are not intended to limit the scope of the invention.

Example 1
N-P-K
Composition 20-20-20
MAP 250
KNO3 377
MKP 90
UREA 263
LIGNOSULFONATE 200
AMMONIUM SULPHATE 0
SOP 0
WATER 200
SUSPENSION AGENT 30
GAMMACACIA 50

Example 2
S NO Component name Formulatio-1
w/v % Formulation-2 w/v % Formulation-3
w/v % Formulation-4
w/v Formulation-5
w/v
1 H3PO4 20 25 XXXXX 33.33 20
2 HNO3 20 25 25 15
3 NH4OH 20 25 25 15
4 KOH 20 XXXXX 25 33.33 20
5 Lignosulfonate 20 25 25 33.33 15
6 Micronutrients and trace elements XXXXXX XXXXXX XXXXX XXXXX 15
7 Adjuvants/Aquafiller Optional Optional Optional Optional Optional

Example 3:
Field trail Experiment-1 with Example-1 20-20-20-(N-P-K) on Soya bean crop
Field trail Data on Soya bean crop:
The filed trial data was conducted on soya bean crop using N-P-K Lignosulfonate based nutrition product vis-à-vis Farmer’s practice.
Dose: 20 % of Ligno sulfonate based nutritional solution was used for the Field trail conducted 1 acre. Accordingly, 5.0 L of Ligno sulfonate based nutritional solution prepared for at basal stage and later two growth stages through fertigation like flowering and fruiting.
Treatment Plant height at 65 days (cm) No of Pods / plant Pod length (cm) Soybean Grain Yield (q/ac) % Yield Increase
Farmers' Practice 37.8 48.6 4.1 3.08
Ligno sulfonate wsf grade-N-P- K-20-20-20 45.6 59.2 4.5 3.97 29

Fertigation is a method of fertilizer application in which fertilizer is incorporated within the irrigation water by the drip system. As is evident from the above table, the fertigation with lignosulfonate complex of NPK fertilizer increased the plant height, pod length and number of pods/plant over conventional farmer’s practice. The intercrop, soybean was harvested. The soybean grain yield increased by 28.9% with the use of Lignosulfonate C-N-P solution over farmers’ practice. The results of this experiment can be summarised as below.

1. Higher soybean biomass recorded due to vigorous plant growth in soybean crop.
2. Root nodules were counted in random plants at peak vegetative stage. 18-20 number of root nodules was found when compared to 12-14 numbers in farmers’ practice.
3. Pod filling is better with bold and good shape grains in the plants treated with lignosulfonate complex of NPK fertiliser solution.

Field trails Experiment-2 using Example-1 20-20-20-(N-P-K) on Green gram
Field trail Data on Green gram crop using N-P-K Lignosulfonate based nutrition product -20-20-20 and compared the same with Farmer practice
Dose: 20 % of Ligno sulfonate based nutritional solution was used for the Field trail conducted 1 acre. Accordingly, 5.0 L of Ligno sulfonate based nutritional solution prepared for at basal stage and later two growth stages through fertigation like flowering and fruiting.
Treatment Plant height at 65 days (cm) No of Pods / plant Pod length (cm) Grain Yield (q/ac) % Yield Increase
Farmers' Practice 36.7 12.1 9.0 1.7
Ligno sulfonate wsf grade-N-P-K 20-20-20 22.6 26.4 13.0 2.5 47.1%

As is evident from the above table, the fertigation with lignosulfonate complex of NPK fertilizer gave higher seedling establishment, number of pods/plant, pod length, number of grains/pod and test weight than farmers practice.
In Green gram cropping system, green gram was harvested and gave 47.1% increase in green-gram grain yield over farmers’ practice. The results of this experiment can be summarised as below.
1. Crop growth is vigorous and greener at vegetative.
2. Higher number of secondary branches and root nodules observed over farmers practice.
,CLAIMS:
1. Lignosulfonate complex of water soluble N, P, K fertilizer composition comprises;
a) Lignosulfonate in an amount of 10 to 25%;
b) Water soluble source of Phosphate in an amount of 20 to 30%;
c) Water soluble source of Potassium in an amount of 8 to 12%;
d) Water soluble source of nitrogen in an amount of 20 to 30%.

2. The Lignosulfonate complex as claimed in claim 1, wherein, the composition optionally comprises;
a) suspending agent(s) in an amount of 2 to 5%;
b) gammacacia in an amount of 30 to 60% and
c) other carriers.

3. The Lignosulfonate complex as claimed in claim 1, wherein, the water soluble source of potassium is selected from the group consisting of ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, potassium phosphate, di-ammonium phosphate.

4. The Lignosulfonate complex as claimed in claim 1, wherein, the water soluble source of phosphate is selected from the group consisting of nitrogen-potassium-phosphorus granulates, potassium phosphate, potassium chloride, potassiun nitrates, potassium sulfates, poly phosphates, phosphite, or combinations thereof.

5. The Lignosulfonate complex as claimed in claim 1, wherein, the water soluble source of nitrogen is selected from the group consisting of urea, amino acids, ammonium nitrates, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate potassium nitrates, or combinations thereof.
6. The Lignosulfonate complex as claimed in claim 1, wherein, the Lignosulfonate are typically selected from the group consisting of sodium lignates, alkaline metal lignates, ammonium lignates, calcium lignates, potassium lignates, Amino acid chelated lignite or mixtures thereof.

7. A process for preparation of lignosulfonate complex of N, P, K water soluble fertilizers which process comprises;
a) Activating the carbon molecules of lignosulfonate by treating with Phosphoric acid at ambient temperature;
b) Slowly adding 100 % water soluble Nitrogen source at 30°C under continuous stirring to complete the reaction;
c) Slowly adding 100 % water soluble potassium source at 30°C under continuous stirring to complete the reaction;
d) Slowly adding 100 % water soluble Phosphorous source at 30°C under continuous stirring to obtain lignosulfonate complex of N, P, K fertiliser.

8. The process as claimed in claim 7, wherein, the carbon molecules of lignosulfonate is selected from the group consisting of sodium lignates, alkaline metal lignates, ammonium lignates, calcium lignates, potassium lignates or mixtures thereof.

9. The process as claimed in claim 7, wherein, the water soluble source of potassium is selected from the group consisting of ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, potassium phosphate, di-ammonium phosphate.

10. The process as claimed in claim 7, wherein, the water soluble source of phosphate is selected from the group consisting of nitrogen-potassium-phosphorus granulates, potassium phosphate, potassium chloride, potassiun nitrates, potassium sulfates, or combinations thereof.
11. The process as claimed in claim 7, wherein, the water soluble source of nitrogen is selected from the group consisting of urea, ammonium nitrates, ammonium phosphates, nitrogen-potassium-phosphorus granulates, mono-ammonic phosphate, di-ammonium phosphate potassiun nitrates, or combinations thereof.

12. A method of providing sustainable nutrient supply to crops which method comprises providing to the crops an effective amounts of the lignosulfonate complexes of water soluble fertilizers, as claimed in claim 1, to improve the yield and quality of the produce.