Claims:I claim
1. The method of detecting the amount of nutrients in the soil is composed of
a) A soil testing strip composed of at least more than one reagent coat
b) Detection of at least more than one soil nutrients using standard color code
2. The embodiment and the methods as claimed in claim 1, for the detection system
comprises of either manual or automatic detection system wherein in the manual
detection system, a color code is used for visual comparison of results in test-strip and
in case of automated detection, the components of color such as CYMK is used for
determining the final concentration of nutrient in the soil.
3. The embodiment and the methods as claimed in claim 1 that is, the standard color
codes and its corresponding nutrient concentration comprising kg/hectare or kg/acre
and its equivalent units including mass of nutrient per area and mass of nutrient per
volume, conveying to user directly the amount of nutrients present in the soil.
4. The embodiment and the methods as claimed in claim 1, wherein the calibration of
standard color codes includes incorporation of the effect of using extracting agents
and nullifying the effect of interfering ions and masking agents.
a) Wherein the calibration of standard color code is done by modifying the
intensity of color based on calibration factor, or
b) Wherein the calibration of standard color code is done by modifying the
nutrient concentration value for a particular color based on calibration factor
5. As an acquisition member of claim 1, the major soil nutrients selected from the
periodic table includes, nitrogen, phosphorous, potassium, zinc, boron, manganese,
iron and copper
6. As an acquisition member of claim 1, the method of detection involves comparison
of the final color in the reagent coat with the universal color chart (in case of manual)
and RGB or other color codes in case of automation.
7. As an acquisition member of claim 1, the procedure for color development involves
dipping the test-strip in soil solution, preferably for few seconds followed by a
preferential and non-mandatory waiting time, preferably from few seconds to several
minutes for color development.
8. As an acquisition member of claim 1, the working principle of the soil test-strip and
detection system is explained as follows
a) The reagent coat is composed of chemical reagents which develops color
when the target nutrient comes in contact with it
b) The intensity of the color is related to the amount of target nutrient in sample
c) The color of the reagent coat is compared with calibrated standard color chart
and the amount of nutrient in the field is obtained
9. As an acquisition member of claim 1, wherein the reagent coat comprises of many
chemical agents including the masking agents in addition to color developing agents
10. Components of test-strip includes a support base [543] onto which the reagent
coats are attached [476] facilitated by an optional adhesive layer [323 , Description:Soil testing strips
FIELD OF INVENTION
[0001] Embodiment and methods disclosed in the of present invention relates to
analytical instrumentation and techniques, more specifically related to soil testing and
its associated technology.
INTRODUCTION
[0002] Test strips have long been used for testing various analytes in sample.
Economical, easy to use, rapid detection and lower chemical requirements are some
features to spur the demand for test strips in the market. With the advancement in the
detection technology, it is now possible to determine concentration of analyte
accurately and precisely which is evolving day by day with advancement in detection
driven by algorithm. Still, there is no reliable soil testing strips in the market,
specifically due to various bottle necks in the soil testing process. For the first time, a
soil testing strip is disclosed with the ability to solve the bottle necks are listed below.
[0003] Extraction process and interfering ions: Several scientific publications support
mono extraction system for extracting the major micro nutrients from soil. Some
suggest the requirement for extraction using more than one chemicals. Although the
major need for extracting agents is to extract specific nutrients from the soil. It is to be
noted that by using water as extracting agent, the amount of micro and macro
nutrients extracted from soil is less compared to the extracting agent. By quantifying
the relationship between the difference in level of of nutrients extracted with water
and with extracting agents, the corrections can be suitably incorporated in test-strip
universal color code. Similarly, the presence of other ions can be masked using
specific masking agents from the vast number of masking agents reported in the
literature.
[0004] Accuracy and precision: Colorimeter/UV-Visible based detection of soil micro
and macro nutrients are time consuming and very laborious. A step further, these
analytical instruments are inaccurate and not precise for estimation of absorbance as
the soil solution contains various organic matters and minute components even after
filtration that affects the absorption and or transmittance of light. This results
inaccuracies and precision of results, rendering the data useless. On the other hand,
test-strips can be used to accurately show the color change as it is directly related to
the color change based on the immobilized reagents and it does not have any
influence from the light absorbance or transmittance. Nowadays, Several high-end
analytical instruments are available to further accurately estimate the color in the teststrip
based on color code (CMKY, RGBY etc) and efficient algorithms, thereby
increasing the accuracy and precision of test-strips to near true values. From the
accuracy and precision point of view, test-strips are evolving and ahead of the
conventional absorbance -transmittance based analytical instruments.
[0005] Time constrains and laborious: By far, the conventional method of measuring
the concentration of soil nutrients is very time consuming. To test a complete micro
and macro soil nutrients as mentioned in the soil health card scheme proposed by the
government of India (2021), it takes more than one hour and very laborious. On the
other hand, test-strips are rapid and instantaneous. On average it takes less than few
minutes for macro nutrients to less than 10-15 minutes for micro and secondary
nutrients. It is to be noted that the active labour time is less than few seconds and the
remaining time is only for the color development, saving the labor’s effort to great
extent. Most importantly, the demand for soil testing before the cropping season is
high that the demand cant be catered using the existing absolute technology. The
proposed innovation can help to cater the demand for soil testing in less time.
[0006] Cost: The quantity of reagents required in colorimeter/UV-Visible based
methodologies are significantly higher compared to test-strips. Because of reduction
in chemical requirements and the simplicity in manufacturing, cost for complete soil
nutrient analysis is at least 10-15x less compared to conventional methods.
[0007] Accessibility: Due to the complexity and the requirement of specialized
training and skill set for operating colorimeter/UV-Visible based instruments, farmers
cannot measure their own soil in-field. The newly proposed test-strip, for the first
time makes it easy for farmers to measure all soil nutrients in one go.
BRIEF SUMMARY
[0008] the exemplary embodiments of the present disclosure are directed towards a
test strip and standard color chart specifically designed for soil testing purposes.
[0009] the exemplary embodiments of the present disclosure are directed towards a
test strip having at least one or more than one reagent chemical coated sections that
can be used to identify at least one or more than one nutrients in the soil.
[0010] the exemplary embodiments of the present disclosure are directed towards the
test strip detection through the standard reference color chart corrected with calibrated
values, which in turn is dependent on several factors associated with the sample
including but not confined to the effect of extracting agent as known to the person
skilled in the art.
[0011] the exemplary embodiment of the present disclosure are directed towards the
test strip which is rapid, precise, accurate and low cost due to the interventions as
highlighted in [0010] to [0011].
[0012] the exemplary embodiment of the present disclosure are directed towards the
test strip wherein the test-strip changes it color in proportion to the amount of
nutrients present in the soil.
BRIEF DESCRIPTION OF DRAWINGS AND FIGURES
[0013] Figure 1 shows one of the examples of soil test-strips arrangements. The left
most is an example of soil macro nutrient test-strip, right most is an example of soil
micro nutrient test-strip and the last one is an example of all in one soil test-strip.
DETAILED DESCRIPTION
[0014] the present disclosure is not limited in its application to the details of
construction and the arrangement of components set forth in the following description
or illustrated in the drawings both read with or without claims. The phraseology and
terminology is solely used for description of the disclosure and should not be regarded
as limiting.
[0015] the use of “Including”, “comprising” or having” and variations thereof herein
is meant to encompass the items listed and their equivalents as well as additional
items. The terms “a” and “an” never denote limitation of quantity under any
circumstances but notify the presence of at least one of the referenced item. The
numbering in the diagrams does not denote any order, quantity or importance rather
used to distinguish one element from another. The phrase “maximum” and
“minimum” is used to refer the relative magnitude of the factor in discussion.
[0016] Figure 1 is a schematic representation of the test strip made of plastic base
[543] onto which the reagent strip [476] is adhered. It is to be noted that the chemical
coated/ adsorbed onto the reagent strip is mainly used for detection of analytes than
the other component of test strip as known to the person skilled in the art.
Embodiment shows the presence of adhesive layer which bonds the reagent
containing strip with the plastic strip. The reagent strip contains the regents, masking
agents and other supplementary chemicals to detect the analyte of interest from the
sample.
[0017] the test strips as shown in figure 1 contains more than one reagent strip. This is
not a mandatory requirement as a test strip can have at least one reagent strip without
any maximum limit. As known to the skilled person in the art, the dimension or the
number of reagent strip on the test strip does not limit the functionality or the
applicability of innovation in whatsoever ways.
[0018] A rectangular test strip containing different reagent coated strip for detection
of basic micro and macro soil nutrients is disclosed. The basic macro and micro
nutrients does not limit the applicability of the invention to only those respective
analytes, rather expressed for conveying the invention in a simplified and easy to
understand manner as evident for the person skilled in the art. For instance, the basic
micro and macro nutrients as per the soil health card scheme of government of India
(In the year 2021) are nitrogen, phosphorous, potassium, Boron, Phosphorous,
Manganese, Copper and Iron.
[0019] Soil samples are collected from the field and the larger debris are removed
manually or passing through the sieve. A total of one kilogram of soil is added with 1
liter of water or soil and water in 1:1 ratio. A sample of this solution is taken in a test
tube and a test strip is dipped in it for a short period of time. The color change is
compared with the standard chart and the final concentration of the nutrient in the
field is determined in kg/ hectare or kg/acre.
[0020] Figure 1 shows the possible arrangements of reagent coats in the soil test-strip
for a limited number of important micro and macro nutrients. It is evident for the
person skilled in the art that these nutrients are provisional and can be expanded to
include as many micro, macro and secondary nutrients in the soil testing portfolio and
the spirit of innovation is not limited to the examples shown in the figure 1.
[0021] A sample of soil test-strip used to determine the major macro nutrient namely
NPK, that is NPK test-strip is shown in figure 1. It is evident for the person skilled in
the art that Nitrogen, Phosphorus and Potassium are the “major” macro nutrients in
the soil and any nutrients so deemed or appropriate to be classified in this category is
also included in this macro nutrient test-strip definition. In order to facilitate the
easiness in conveying the importance of chemical reaction and its intangible
relationship to the innovation, sample reagents used in the reagent coat [0034-0036] is
discussed in the following paragraphs. In no way these reagents limit the applicability
of invention.
[0022] Napthyl amine derivative and sulphanilamide form pink to violet-pink color
via diazotization reaction, whose intensity can be related to the amount of
diazotization which in turn is dependent on the amount of nitrite or nitrate present in
the soil solution when sulphanilamide and naptyl amine is preferably present in excess.
It is evident for the person skilled in the art that there may be more than one method
or other derivatives of this method used for estimating the nitrate and nitrite in soil.
The key relationship with the method proposed and the innovation is these reagents
and methods are used for estimating the soil nutrients and the same is under the ambit
of proposed innovation, more specifically with the presence of more than one reagent
coat in a single test-strip either calibrated with or without the extracting agent effect.
It is also to be noted that apart from the primary ingredients disclosed here, several
other masking agents including but not confined to at least one or all of the
components such as EDTA, NTA and extracting agents be added to increase the
accuracy of the test-strip.
[0023] Dipicrylamine derivative when reacted with potassium exchanges the cation
and forms potassium dipicrylamide, a red color compound whose intensity varies in
relation to the amount of potassium in solution. It is evident for the person skilled in
the art that there may be more than one method (Such as sodium cobaltinitrite
mixtures) or other derivatives of this method used for estimating the potassium in soil.
The key relationship with the method proposed and the innovation is these reagents
and methods are used for estimating soil nutrients and is under the ambit of proposed
innovation, more specifically in presence of more than one reagent coat in a single
test-strip either calibrated with or without the extracting agent effect. It is also to be
noted that apart from the primary ingredients disclosed here, several other masking
agents including but not confined to at least one or all of the components such as
EDTA, NTA and extracting agents be added to increase the accuracy of the test-strip.
[0024] Ammonium molybdate along with ascorbic acid and antimony potassium
tartarate when reacted with the phosphorous results in formation of blue color whose
intensity varies in relation to the amount of phosphorous in solution. It is evident for
the person skilled in the art that there may be more than one method or other
derivatives of this method used for estimating the phosphorous m in soil. The key
relationship with the method proposed and the innovation is these reagents and
methods are used for estimating the soil nutrients and is under the ambit of proposed
innovation, more specifically with the presence of more than one reagent coat in a
single test-strip either calibrated with or without the extracting agent effect. It is also
to be noted that apart from the primary ingredients disclosed here, several other
masking agents including but not confined to at least one or all of the components
such as EDTA, NTA and extracting agents be added to increase the accuracy of the
test-strip.
[0025] Similarly, several color developing agents and other chemical agents are used
for detection of micro nutrients and secondary nutrients such as boron , manganese,
iron, copper, sulfur and zinc. It is evident for the person skilled in the art that
detection of micro and macro nutrients using the test-strip is part of the invention.