Claims:We claim:
1. An apparatus for testing soil, comprising:
- a testing module (12) for testing a soil sample solution to determine an amount of at least one macronutrient present in said sample solution by means of fluorescence-based capillary electrophoresis;
- a testing chip (21) removably positioned in said testing module (12) for holding said sample solution during test, wherein said testing chip (21) includes three or more channels (29 – 32);
- an output module (13) for outputting a test result;
- at least one microcontroller unit (14) electrically connected to each module (12, 13) for controlling a corresponding function; and
- at least one power module (15) for supplying power to said testing module (12), said microcontroller unit (14) and said output module (13),
wherein said testing chip (21) is entirely made of a transparent material and does not include any electrically conductive material, and said testing module includes a third dosing unit (25) for delivering a predetermined volume of a conductive solution to at least one of said channels (29 – 32) in said testing chip (21).

2. The apparatus as claimed in claim 1, further comprising a sample preparation module (11) for preparing a sample solution by mixing soil to be tested and a solvent.

3. The apparatus as claimed in claim 2, wherein said sample preparation module (11) includes:
- a container (16) for containing the solvent and the soil;
- an agitating unit (17) for mixing the solvent and the soil to form a mixture of solid particles and the soil sample solution; and
- at least one filter unit (18) for filtering said mixture to separate solid particles from said mixture, wherein said filter unit (18) includes at least one filter paper (42) removably placed over at least one metallic mesh (43) and a vacuum pump (41).

4. The apparatus as claimed in claim 2, wherein said sample preparation module (11) is releasably attachable to said testing module (12).

5. The apparatus as claimed in claim 4, wherein at least one locking mean is attached to at least one of said sample preparation module (11) and said testing module (12) for holding said sample preparation module (11) in position with respect to said testing module (12) when said sample preparation module (11) is attached to said testing module (12).

6. The apparatus as claimed in claim 1, wherein said output module (13) includes at least one of an LCD, a LED display, a plotting unit, a printing unit and a wireless communication unit.

7. The apparatus as claimed in claim 1, wherein said channels (29 – 32) in said testing chip (21) include at least two inlet channels (29 – 30) and at least one outlet channel (31 – 32).

8. The apparatus as claimed in claim 2, wherein said testing module (12) includes:
- a first dosing unit (23) for receiving said sample solution from said sample preparation module (11) and for delivering a predetermined volume of the soil sample solution to at least one of inlet channels (29 – 30) in said testing chip (21); and
- a second dosing unit (24) for delivering a predetermined volume of a buffer solution to at least one of said inlet channels (29 – 30) in said testing chip (21).
- a third dosing unit (25) for delivering a predetermined volume of a conductive solution to at least one of said inlet channels (29 – 30) in said testing chip (21).

9. The apparatus as claimed in claim 7, wherein said testing module (12) further includes:
- at least one imaging unit (38) for capturing at least one image of at least one of said outlet channels (31 – 32) in said testing chip (21) while testing said soil sample solution; and
- at least one image processing unit (40) for processing said image to determine said amount of each macronutrient present in said sample solution.

10. A method for soil testing apparatus, comprising the steps of:
- introducing a predetermined volume of a soil sample solution into a testing chip, wherein said testing chip includes at least two inlet channels and at least one outlet channel, such that said sample solution enters one of said inlet channel and flows through said outlet channel;
- applying a predetermined voltage to said sample solution, such that each macronutrient present in said sample solution moves along said outlet channel at a different velocity;
- capturing at least one image of said sample solution, while applying said predetermined voltage; and
- analyzing said image to determine an amount of each macronutrient present in said sample solution,
wherein, before introducing said sample solution into said channels, an electrically conductive path is formed along said channels by introducing an electrically conductive solution into said channels.

11. An apparatus for testing soil, comprising:
- a testing module (12) for testing a soil sample solution to determine an amount of at least one macronutrient present in said sample solution by means of fluorescence-based capillary electrophoresis;
- a testing chip (21) removably positioned in said testing module (12) for holding said sample solution during test, wherein said testing chip (21) includes three or more channels (29 – 32);
- an output module (13) for outputting a test result;
- at least one microcontroller unit (14) electrically connected to each module (12, 13) for controlling a corresponding function; and
- at least one power module (15) for supplying power to said testing module (12), said microcontroller unit (14) and said output module (13),
wherein said testing chip (21) is entirely made of a transparent material and does not include any electrically conductive material,
wherein said testing module includes a third dosing unit (25) for delivering a predetermined volume of a conductive solution to at least one of said channels (29 – 32) in said testing chip (21),
wherein a sample preparation module (11) is releasably attached to said testing module (12) for preparing and delivering said soil sample solution to said testing module (12).

12. An apparatus for testing soil, comprising:
- a testing module (12) for testing a soil sample solution to determine an amount of at least one macronutrient present in said sample solution by means of fluorescence-based capillary electrophoresis;
- a testing chip (21) removably positioned in said testing module (12) for holding said sample solution during test, wherein said testing chip (21) includes three or more channels (29 – 32);
- an output module (13) for outputting a test result;
- at least one microcontroller unit (14) electrically connected to each module (12, 13) for controlling a corresponding function; and
- at least one power module (15) for supplying power to said testing module (12), said microcontroller unit (14) and said output module (13),
wherein said testing chip (21) includes at least one electrically conductive path along each channel (29 – 32).
, Description:FIELD OF INVENTION
[0001] The present disclosure relates to agriculture soil testing, and more specifically related to an apparatus for testing soil to determine availability of macronutrients in the soil.
BACKGROUND OF INVENTION
[0002] Role of chemical fertilizers in increasing yield and production has led the agriculture sector to over utilize without prior knowledge of deficiency of the land. With the world population expected to reach 9.7 billion people by 2050, the agricultural sector needs to increase its productivity by 60% compared to that in 2005 to meet the increasing demand of food. Hence, the role of soil and farmers is of greater importance for an agriculture-based country like India. There is no direct method to judge the status of soil health.
[0003] Just like human health, there is no single machine that can be used to access and define deficiencies where the soil is healthy or not. The usage of fertilizers cannot be avoided completely but the excess usage of fertilizers can be avoided if the deficiencies of the soil can be know in prior. This is possible through the accurate identification and remedial measures taken to reduce the usage of chemical fertilizers for obtaining a balanced and sustainable productivity and yield.
[0004] As soil nutrients are an essential part of agriculture, farmers needs to study various aspects of soil before farming for better yield and production for a crop he wants to grow. They should be aware of the nutrients that the soil can provide to the crop that he wants to grow. Conventional methods of testing the soil to determine the deficiencies thereof are time consuming and tedious for the results of fertilizer recommendations to reach the farmers.
[0005] There are various macro and micronutrients that help in growth of plants. Macronutrients contributing to a major portion of nutrient supply to the plants through soil. The macronutrients include Nitrogen (N), Phosphorous (P) and Potassium (K). Nitrogen helps in growth of leaves, Phosphorous contributes to root growth, flower growth and fruit development whereas potassium helps overall functions of the plant growth.
[0006] The fertilizers available in the market are addressing to these nutrient need of soil. Unless the farmers are aware of these values and nutrients, it is difficult for them to choose the right fertilizer for the right crop. The conventional test methods do not provide instant results to the farmers to choose the right crop and hence the fertilizer to it. In a greed and no existing products addressing to these needs, the farmers are not aware of the soil deficiency and thus use the fertilizers as a general and a mandatory step and end up using excess of fertilizers weakening the soil properties.
[0007] Indian Patent Application No.: 201941032268 discloses a device for real-time soil analysis, wherein the soil sample is mixed with certain reagents. The device analyses the color of the mixture and volume/weight based reaction of reagents with the mixture to determine soil fertility. However, this needs an extensive lab setup to conduct the analysis.
[0008] Similarly, Pessl Instruments GmbH has developed a soil macro-nutrients analyzer named “iMETOS MobiLab” for analyzing availability of NO3 and NH4 from the soil and other nutrients from plant sap and other sources. It uses an expensive microfluidic chip to holding the soil sample solution for conducting the test. Furthermore, it requires a certain level of training to handle the device and to conduct the test.
[0009] Hence, there is still a need for a simple, accurate and inexpensive solution for analyzing soil sample that is practicable by common men with or without minimal expertise(requirement of automation in the manual steps).
OBJECT OF INVENTION
[0010] The principal object of the embodiments herein is to provide an apparatus for testing soil on-site in a simple, quick, portable and cost efficient manner with or without minimal manual intervention.
[0011] Another object of the embodiment herein is to avoid any chances of contaminating a soil sample solution between a sample preparation stage and a sample testing stage, while minimizing maintenance cost.
SUMMARY OF INVENTION
[0012] Accordingly, embodiments herein disclose an apparatus for testing soil for its macronutrients and fertilizer recommendation, comprising, sample preparation & pretreatment module, a testing module, a testing chip, an output module, a microcontroller unit and a power module. The testing module tests a soil sample solution to determining an amount of one or more macronutrients present in the soil sample solution by means of fluorescence-based capillary electrophoresis. The microcontroller unit is electrically connected to each module for controlling a corresponding function, while the power module supplies power to each of the sample preparation module, the testing module, the microcontroller unit and said the output module.
[0013] The testing chip is removably positioned in the testing module for holding the soil sample solution during test, wherein the testing chip includes two or more channels. In a preferred embodiment, the testing chip is entirely made of a transparent material and does not include any electrically conductive material.
[0001] In one aspect of the present invention, a sample preparation module prepares a sample solution by mixing soil and a solvent, preferably distilled water. The sample preparation module includes a container for containing the solvent and the soil and an agitating unit positioned in the container for mixing the solvent and the soil by stirring to form a mixture of solid particles and the soil sample solution.
[0014] The testing module includes a first dosing unit for delivering a predetermined volume of the soil sample solution f to one of the channels in the testing chip, a second dosing unit for delivering a predetermined volume of a buffer solution to one of the channels in the testing chip and a third dosing unit for delivering a predetermined volume of a conductive solution to one of the channels in the testing chip.
[0015] Furthermore, the testing module includes two pair of electrodes for delivering a predetermined voltage to ends of the channels in the testing chip. A power conversion unit connected to the electrodes converts the power supplied by the power supply module into the predetermined voltage for supplying to the electrodes. The predetermined voltage influences each macronutrient in the soil sample solution to move along one of the channels at a different velocity. In a preferred embodiment, the macronutrients include nitrogen, potassium and phosphorous.
[0016] The testing module includes an imaging unit for capturing one or more images of the channels while testing the soil sample solution as the solution travels through the channel. Furthermore, an image processing unit in the testing module receives and processes each image to determine the amount of the macronutrients present in the soil sample solution.
[0017] Preferably, before delivering the soil sample solution to one of the channels, the third dosing unit delivers the predetermined volume of the conductive solution to one of the channels in the testing chip, such that conductive solution forms a conductive path along the channels. Upon forming the conductive path, the second dosing unit delivers the predetermined volume of the buffer solution to an inlet of one of the channels in the testing chip. Furthermore, the first dosing unit delivers the predetermined volume of the soil sample solution to an inlet of the other channel in the testing chip. After delivering the soil sample solution, the electrodes are positioned at the ends of the channels, such that a negative electrode is positioned at each inlet, while a positive electrode is positioned at an outlet of each channel. Because of the voltages applied at the channels, an electric field is formed along the conductive path, which in turn forces each macronutrient in the soil sample solution to move along the conductive path at a different velocity based on corresponding ion mobility and conductivity.
[0018] As each macronutrient travels at a different velocity, the macronutrients get separated, and therefore exhibit different colors at different portions of the channel through which they are travelling. By analyzing the images of the channel, the image processing unit determines the amount of macronutrients in the soil sample solution.
[0019] Since the conductive path in the channels is formed by delivering the conductive solution before delivering the soil sample solution, a need for manufacturing the testing chip with electrodes is avoided, and therefore reducing the cost of the apparatus drastically without compromising with a testing capability of the apparatus.
[0020] In another aspect of the present invention, the sample preparation and pretreatment module is releasably attachable to the testing module, wherein a locking means is attached to the sample preparation module or the testing module for holding the sample preparation module in position with respect to the testing module when the sample preparation module is attached to the testing module. Furthermore, the first dosing unit is fluidly connected to the sample preparation module for receiving the filtered sample solution from the sample preparation module.
[0021] Since the sample preparation module is fluidly connected to the testing module, the soil sample solution prepared in the sample preparation module can be directly delivered to the testing module which in turn automatically delivers a predetermined volume of the soil sample solution into the testing chip. Therefore, the present invention avoids a need for transferring the soil sample solution to an intermediate container or any manual intervention related thereto for delivering to the testing module or to the testing chip. Thus, the present invention eliminates any chances of contaminating the soil sample solution during the transfer process, which in turn helps in improvising an accuracy of test results. Furthermore, by means of controlling each module in the apparatus using the microcontroller unit, the apparatus automates the entire process of soil testing from sample preparation to outputting test results, thus avoiding a need for an expert or training to conduct the test.
[0022] Accordingly, embodiments herein disclose a method for soil testing, comprising the steps of: introducing a predetermined volume of a soil sample solution into a testing chip, applying a predetermined voltage to the soil sample solution, capturing one or more images of the soil sample solution, while applying the predetermined voltage and analyzing each image to determine an amount of each macronutrient present in the soil sample solution
[0023] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0024] The method and the system are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
FIGURE 1 shows an exploded perspective view of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 2 shows a perspective view of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 3 shows a perspective view of a testing chip of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 4 shows a front view of a testing chip of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 5 shows a top view of a testing chip of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURES 6 & 7 show a top view of a testing chip of different configurations, in accordance with an exemplary embodiment of the present invention;
FIGURE 8 shows a schematic representation of an apparatus for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 9 shows a flow diagram of a method for soil testing, in accordance with an exemplary embodiment of the present invention;
FIGURE 10 shows an exploded perspective view of a filter unit of the apparatus for soil testing, in accordance with an exemplary embodiment of the present invention; and
FIGURE 11 shows a perspective view of a filter unit of the apparatus for soil testing, in accordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION
[0025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0026] FIGURE 1 shows an exploded perspective view of the apparatus for soil testing, in accordance with an exemplary embodiment of the present invention. The apparatus (10) comprises a sample preparation module (11), a testing module (12), an output module (13), a microcontroller unit (14) and power module (15). The microcontroller unit (14) is electrically connected to each of the sample preparation module (11), the testing module (12), the output module (13) and the power module (15) for controlling each function of the sample preparing module (11), the testing module (12), the output module (13), the microcontroller unit (14), the power module (15). Preferably, the microcontroller unit includes a Peripheral Interface Controller (PIC)-based microcontroller, ATMEGA microcontroller, Arduino microcontroller or any other commercially available microcontroller device.
[0027] The power module (15) is electrically connected to each of the sample preparation module (11), the testing module (12) and the output module (13), the microcontroller unit (14) for supplying power. In a preferred embodiment, the power module (12) includes a battery or a generator as a power source. Alternatively, AC mains can be connected as the power source. The sample preparation or pretreatment module (11) prepares a sample solution by mixing soil to be tested and a solvent, preferably distilled water. The ratio of soil to the solvent to be mixed is 1:5. The sample preparation module (11) includes a container (16) for containing the solvent and the soil and an agitating unit (17) provided within the container (16) for mixing the solvent and the soil to form a mixture of homogenous solid particles and the soil sample solution. In a preferred embodiment, the agitating unit (17) includes a stirrer (19) and a motor (not shown) for rotating the stirrer (19). A rotational speed of the motor is controlled using the microcontroller unit (14). Alternatively, the agitating unit (17) may include any other conventional means for mixing the soil and the solvent. Additionally, filter unit (18) is provided in the sample preparation module (11) for filtering the mixture to separate the solid particles from the mixture.
[0028] In a preferred embodiment, the filter unit (18) includes a filtering means (not shown) and a vacuum pump (41) in fluid connection with the filtering means (not shown) for extracting the soil sample solution through the filtering means. In a preferred embodiment, the filtering means includes two layer structure, wherein a filter paper (42) such as standard Whatman filter paper, forms an upper layer and a metallic mesh (43) forms a bottom layer, as shown in FIGURES 10 & 11. More preferably, the filter paper (42) is removably placed over the mesh (43), such that the filter paper (42) can be removed along with a filtrate i.e. solid substance, and a new filter paper placed over the mesh (43), after each test cycle. Alternatively, any other conventional single/multi-layered filtering means may be used as the filtering means. Additionally, the sample preparation module (11) includes a hose pipe (22) for connecting the container (16) and the filter unit (18) and one or more valves (not shown) controlled by the microcontroller unit (14) for selectively allowing a flow of the soil sample solution through the hose pipe (22).
[0029] The sample preparation module (11) is releasably attachable to the testing module (12), wherein the sample preparation module (11) and the testing module (12) are in fluid connection with one another when attached together. A locking means (not shown) is attached to the sample preparation module (11) and/or the testing module (12) for holding the sample preparation module (11) in position with respect to the testing module (12) when the sample preparation module (11) is attached to the testing module (12). In a preferred embodiment, the locking means includes a clamp, a threaded fastener or any other conventional fastening means.
[0030] Furthermore, the output module (13) can also be releasably attached to the testing module (12), such that the entire apparatus (10) is formed as a single unit as shown in FIGURE 2. The output module (13) includes one or more outputting means such as LCD, LED display, plotting unit, wireless communication unit and printing unit, for outputting the test result. Furthermore, the wireless communication unit may communicate the test results to a user device e.g. mobile phone, desktop computer and portable computer, by means of short messaging service (SMS) or notification readable through a web application or a mobile app. In a preferred embodiment, the outputting means provides the test result in the form of color coding representing a proportion of the macronutrients in the soil and one or more recommendations on a type of fertilizer to be applied to compensate for any lacking macronutrients.
[0031] FIGURE 8 shows a schematic representation of a testing module of the apparatus for soil testing, in accordance with an exemplary embodiment of the present invention. The testing module (12) includes a first dosing unit (23), a second dosing unit (24) and a third dosing unit (25), wherein each dosing unit (23 – 25) includes a valve means (26 – 28) controlled by the microcontroller unit (14). Additionally, the testing module (12) includes a support means (20) for receiving a testing chip (21) to be removably positioned in the testing module (12) for holding the soil sample solution during the test. Preferably, the testing chip (21) is a microfluidic-based Soil-on-Chip. The support means (20) may be in the form of a drawer or a tray that is movable between a testing position and a loading/unloading position. At the loading/unloading position, the support means (20) is out of the testing module (12) for placing/removing the testing chip (21) Soil On Chip on/from the support means (20). At the testing position, the support means (20) moves the testing chip (21) to a preset position for placing a plurality of electrodes for conducting the test.
[0032] FIGURE 3 – 5 show different view of a testing chip of the apparatus for soil testing, in accordance with an exemplary embodiment of the present invention. The testing chip (21) includes three or more channels (29 – 32), wherein each channel (29 – 32) is connected to the other channels (29 – 32) at one end. A cavity (33 – 36) is formed at a free end of each channel (29 – 32). A width of each channel (29 – 32) is configured to prevent any movement of the soil sample solution along the channels (29 – 32) unless an electric field is applied. Preferably, the width of each channel is within a range of 500-1000 microns. Similarly, the testing chip is about 5 centimeters (cm) in length, 3-5 cm in width and 1 cm in thickness.
[0033] In a preferred embodiment, two channels (29 – 30) function as inlet channels (29 – 30) to receive the soil sample solution and a buffer solution, respectively, while the other channels (31 – 32) function as outlet channels (31 – 32) to drain a waste solution and a separated nutrient solution, respectively. Preferably, at least one outlet channel (32) is configured to be longer than the other channels (29 – 31), as shown in FIGURES 3 - 5. More preferably, a length of the outlet channel (32) is within a range of 35 – 40 mm.
[0034] Alternatively, the testing chip (21) may include an interconnecting channel (37) connected to two inlet channels (29 – 30) at one end and two outlet channels (31 – 32) at the other end, as shown in FIGURE 6, wherein a length of the interconnecting channel (37) is within a range of 35 – 40 mm. In a preferred embodiment, the testing chip (21) is entirely made of a transparent material e.g. Polydimethylsiloxane (PDMS), Poly (methyl methacrylate) (PMMA) or polyvinyl chloride (PVC). Alternatively, the testing chip (21) may also be manufactured from any other plastic material with a Young’s modulus of 0.13 – 4.00 gigapascals (GPa), and does not include any electrically conductive element. Preferably, the testing chip (21) is made by three-dimensional printing. Alternatively, the testing chip (21) may also be manufactured by a molding process using micro and nano fabrication facilities. Furthermore, the testing chip (21) may also include two inlet channels (29 – 30) connected to a single outlet channel (32) as shown in FIGURE 7.
[0035] Returning to FIGURE 8, the first dosing unit (23) includes a container/tank (not shown) which is in fluid connection with an outlet (not shown) of the sample preparation module (11) and a valve (26) operated by the microcontroller unit (14). The container/tank receives and holds the soil sample solution from the sample preparation module (11), such that when the valve (26) of the first dosing unit (23) is operated by the microcontroller unit (14), the first dosing unit (23) delivers a predetermined volume of the soil sample solution to the cavity (33) in the testing chip (21).
[0036] The testing module (12) includes a second dosing unit (24) and a third dosing unit (25) for delivering a predetermined volume of a buffer solution and an electrically conductive solution to one of the cavities (33, 34) in the testing chip (21), respectively. In a preferred embodiment, the buffer solution includes one or more of Tris- Borate ethylenediaminetetraacetic acid (EDTA) buffer (TBE) with pH level of 8.0) Tris-Acetate EDTA buffer (TAE) with pH level above 8.0, Tris Glycine buffer (TG) with pH level above 8.5, Tria-Citrate-EDTA buffer (TCE) with pH level of 7.0, Tris- EDTA buffer (TE) with pH level of 8.0, Tris-Maleic acid-EDTA buffer (TME) with pH level of 7.5 and Lithium Borate-buffer (LB) with pH level of 8.6. Similarly, the electrically conductive solution may include but not limited silver nitrate (AgNO3), sodium chloride (NaCl), sodium hydroxide (NaOH), acetonitrile, diethylene glycol dimethyl ether, dimethoxyethane, acetic acid and ammonia. Alternatively, the electrically conductive solution may also be any solution capable of conducting electricity, while not reactive to the buffer solution or to a surface of the testing chip (21).
[0037] Similar to the first dosing unit (23), each of the second dosing unit (24) and the third dosing unit (25) includes a container (not shown) for holding the respective solution and a valve (27, 28) operable by the microcontroller unit (14) for controlling a volume of the respective solution delivered. The volume of the soil sample solution, buffer solution and the electrically conductive solution varies with dimensions of the channels (29 – 32) and the corresponding cavities (33 – 36).
[0038] Optionally, the soil sample solution may be prepared separately by any conventional means including manual preparation or any mixing device and then filled in the container/tank of the first dosing unit (23). Alternatively, the predetermined volume of the soil sample solution is directly delivered into the cavity (33) in the testing chip (21) before the testing chip (21) is placed in the support means (20). Similarly, the buffer solution and the electrically conductive solution can also be manually filled in the respective containers or be directly delivered into the respective cavities (33, 34) in the testing chip (21) before the chip is placed in the support means (20).
[0039] Furthermore, the testing module (12) includes one or more electrodes (not shown) for delivering a predetermined voltage across the channels (29 – 32) in the testing chip (21). Preferably, the predetermined voltage is within a range of 10 – 20 kilovolts (kV). Alternatively, the electrodes, power conversion unit and the power module (15) may also be configured to deliver any voltage that is applicable for carrying out an electrophoresis process. A positive electrode is positioned at a free end of each inlet channel (29 – 30) and a negative electrode is positioned at a free end of each outlet channel (31 – 32). Preferably, the positive electrode is positioned in the cavities (33 – 34), while the negative electrode is positioned in the cavities (35 – 36). A power conversion unit (not shown) in the testing module (12) is controlled by the microcontroller unit (14) for converting the power supplied by the power module (15) into the predetermined voltage to be supplied to the electrodes. The electrodes are electrically connected to an output terminal of said power conversion unit.
[0040] The microcontroller unit (14) is configured to control the power conversion unit in such a manner, that the macronutrients in the soil sample solution are moved along a corresponding outlet channel (32) towards the cavity (36) at the end thereof. Preferably, the predetermined voltage influences each macronutrient in the soil sample solution to move along the outlet channel (32) at a different velocity.
[0041] The testing module (12) further includes an imaging unit (38) for capturing one or more images of the outlet channel (32) through which the macronutrients are moving, while testing the soil sample solution, and an image processing unit (40) for processing the captured images to determine an amount of each macronutrient present in the soil sample solution. The imaging unit (38) may include but not limited to a digital camera, charge-coupled device (CCD) array or any other digital imaging device. Optionally, the imaging unit (38) includes a light source (39) such as ultraviolet (UV) light, capable of emitting radiations within a bandwidth of 200 – 800 nanometers (nm), for illuminating the outlet channel (32) through which the macronutrients travel during the testing process. Alternatively, the light source (39) may emit radiations within a bandwidth of 200 – 2500 nm. Preferably, the imaging unit (38) captures light rays reflected by the macronutrients. Alternatively, light rays pass through the outlet channel (32) and get scattered by the macronutrients, which are then captured by the imaging unit (38) and the images are analyzed at the image processing unit (40).
[0042] The microcontroller unit (14) receives test results determined by the image processing unit (40) and controls the output module (15) accordingly for outputting the test results in a format that is readable by a user. Preferably, the output module (15) includes a printing unit for printing out the test results on a printing medium i.e. paper, a display unit e.g. LCD or LED, for displaying the test results.
[0043] Optionally, the microcontroller unit (14) may also be configured to provide suggestions on a fertilizer to be used for compensating any lack in macronutrients. Furthermore, the apparatus (10) may include a global position system (GPS) device for linking a location data with the test results in real-time and a storage device for recording the test results for future analytics. The apparatus (10) may also include a wireless transceiver in the output module (15) for communicating test results to a user device e.g. mobile phone, desktop computer and portable computer, in the form of SMS or a notification readable through a web application or a mobile app and/or for receiving a control command to/from a remote device such as cloud server, the user device and the like.
[0044] FIGURE 9 shows a flow diagram of the method for soil testing, in accordance with an exemplary embodiment of the present invention. The method comprises the steps of: introducing a predetermined volume of a soil sample solution into a testing chip, applying a predetermined voltage to the soil sample solution, capturing one or more images of the soil sample solution, while applying the predetermined voltage and analyzing each image to determine an amount of each macronutrient present in the soil sample solution.
[0045] In a preferred embodiment, the testing chip includes at least two inlet channels and at least one outlet channel, such that the soil sample solution enters one of the inlet channels and flows through the outlet channel when the soil sample solution is introduced into the testing chip. Before introducing the soil sample solution into the inlet channel, an electrically conductive path is formed along the channels by introducing an electrically conductive solution into the channels. When the predetermined voltage is applied to the soil sample solution, each macronutrient present in the soil sample solution moves along the outlet channel at a different velocity.
[0046] In an alternate embodiment, the channels (29 – 32) of the testing chip (21) include a conductive path (not shown) along a bottom portion of the channels (29 – 32), so as to conduct electricity and create an electric field for moving the buffer solution and the soil sample solution along the outlet channel (32), during the testing process. The conductive path is formed by depositing, along the channels (29 – 32), a thin wire of silver or any other electrically conductive material that is not reactive to the buffer solution and the soil sample solution. Entire process of soil testing is described in detail in the following paragraphs with respect to FIGURES 1 – 8.
[0047] A soil to be tested and a solvent are introduced into the container (16) in the sample preparation module (11) and the apparatus (10) is switched on. The microcontroller unit (14) controls the agitating unit (17) to mix the soil and the solvent for a preset time period, preferably 2-4 minutes, to form a mixture of solid and liquid substances. After the preset time period, the microcontroller unit (14) stops the agitating unit (17) and opens the valve in the hose pipe (22) to allow the mixture to flow into the filter unit (18). The vacuum pump in the filter unit (18) is operated to suck the liquid substance in the mixture through the filtering means, such that the solid substance is separated by the filtering means. Upon removing the homogenous liquid substance from the mixture, the outlet of the sample preparation module (11) is opened to allow the liquid substance to be filled in the first dosing unit (23) of the testing module (12) as the soil sample solution to be analyzed.
[0048] The microcontroller unit (14) operates the valve (28) of the third dosing unit (25) to allow a predetermined volume of the electrically conductive solution to be delivered to the cavity (33) of the testing chip (21) in the support means (20). The electrically conductive solution flows through the channels (29 – 32) and forms a conductive path along the channels (29 – 32) and the corresponding cavities (33 – 36) in the form of a layer of the electrically conductive solution coated at least at a bottom portion of the channels (29 – 32) and the corresponding cavities (33 – 36).
[0049] After the conductive path is formed, the microcontroller unit (14) operates the valve (27) of the second dosing unit (24) to allow a predetermined volume of the buffer solution to be delivered to the cavity (34) of the testing chip (21). Next, the microcontroller unit (14) operates the valve (26) of the first dosing unit (23) to deliver the predetermined volume of the soil sample solution to the cavity (33). Due to the dimensions of the channels (29 – 32), the soil sample solution stays at the cavity (33). Finally, the electrodes are placed at the respective cavities (33 – 36) and the predetermined voltage is applied at the soil sample solution through the conductive path.
[0050] Any charged particle in a liquid medium migrates under the influence of an electric field. Depending on a polarity of the charged particle, it moves towards a cathode or an anode. An ampholyte becomes positively charged in acidic condition and migrates to cathode, and the same becomes negatively charged in alkaline condition and migrates to the anode. Under the electric filed, a velocity of the particle is determined by an amount of charged carried by the particle and a frictional coefficient of the particle.
[0051] Under the influence of the applied voltage, the macronutrients in the soil sample solution start moving along the channel (32). Due to their differences in conductivity and frictional coefficient, a velocity of each macronutrient is different from the other macronutrients. Therefore, the macronutrients get separated along the channel (32) and exhibit different colors according to their fluorescence energy. Upon expiry of a preset time period after the voltage is applied, the microcontroller unit (14) operates the imaging unit (38) to capture one or more images of the soil sample solution along the channel (32). The image processing unit (40) receives the captured images and analyzes each image to detect different colors captured in the image and intensity thereof. Based on the colors detected, the image processing unit (40) confirms presence of the corresponding macronutrients and based on the intensity of each detected color, the image processing unit (40) determines an amount of the corresponding macronutrients in the soil sample solution.
[0052] Once the analysis is completed, the microcontroller unit (14) receives the test results from the image processing unit (40) and controls the output module (13) to output the test results. If the test results from one or more images differ from the other images, the apparatus (10) may be configured to output a minimum and maximum readings of each macronutrient and/or to calculate and output an average of such readings. Even though the microcontroller unit (14) is illustrated as a single unit located in the testing module (12) in the accompanying drawings, it is to be understood that there may be multiple microcontrollers located in different modules (11, 12, 13, 15) of the apparatus (10) co-operatively working to control the entire function of the apparatus (10). Similarly, it is to be further understood that the accompanying drawings are for illustration purpose only and that the actual dimensions of the present invention may vary with user requirements. The list of reference numerals and part names thereof are as follows:
(10) Apparatus for soil testing
(11) Sample preparation module
(12) Testing module
(13) Output module
(14) Microcontroller unit
(15) Power module
(16) Container
(17) Agitating unit
(18) Filter unit
(19) Stirrer
(20) Support means
(21) Testing chip
(22) Hose pipe
(23) First dosing unit
(24) Second dosing unit
(25) Third dosing unit
(26 - 28) Valves
(29 - 30) Inlet channels
(31 - 32) Outlet channels
(33 - 36) Cavities
(37) Intermediate channel
(38) Imaging unit
(39) Light source
(40) Image processing unit
(41) Vacuum pump
(42) Filter paper
(43) Metallic mesh
[0053] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.