Description:FIELD OF THE INVENTION
[0001] The present invention relates to the field of IoT-enabled environmental sensing, and more particularly, the present invention relates to the Rapid soil nutrient detection system for on-site applications.
BACKGROUND FOR THE INVENTION:
[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known, or part of the common general knowledge in any jurisdiction as of the priority date of the application. The details provided herein the background if belongs to any publication is taken only as a reference for describing the problems, in general terminologies or principles or both of science and technology in the associated prior art.
[0003] Soil macronutrients are highly essential in plant development and growth and are the foundation of vigorous and rewarding crops. Soil macronutrients exist in two types: macronutrients and micronutrients. Each has a separate function in some processes in plants such as photosynthesis, synthesis of proteins, and elongation of the root; thus, if appropriately balanced, they account for maximum plant fitness, yield, and resistance to diseases. Micronutrients occur in minute quantities but are of extreme significance to plant health and become involved in diverse metabolic as well as physiological processes within the plant. Micronutrients regulate enzyme activity, growth, and development of the plant, and metabolism. Deficiency or excess micronutrients is cataclysmic for crop yield and quality. Although governments and agencies are attempting to screen and monitor soil nutrient levels, the quantification of nutrient surpluses or shortages is hindered by a combination of conditions that reduce both efficiency and response rates.
[0004] The current soil testing process often involves sampling soil and taking it to the leading laboratories (district/universities/ research institutions) for analysis. They are typically analysis-based instruments, and obtaining the soil health card result can take 10-15 days due to the backlog of samples, the functioning and availability of the instruments, and the technical workforce. In the meantime, time is passing for the farmers who cannot wait for long to start sowing or planting. Moreover, these processes require experienced technicians, strict sample handling procedures, and access to expensive and sensitive laboratory equipment. These inputs are unavailable in remote locations and rapid and reliable testing is virtually impossible. No matter how widely the newer, more sophisticated technologies, such as the nutrient analyzer, are being used, these rely on high-level technology and clean laboratory settings. They are rigid, power-hungry, and require complex processes that exceed the capabilities of non-professionals. Thus, their applicability in the field where quicker decision-making is most necessary is restricted. In addition, most portable instruments available today can only analyze a few nutrients, and their high cost makes them unaffordable for marginal and mediocre farmers. They also tend to provide quantified results, but may be susceptible to imprecise results due to the timely non-calibration of the instrument.
[0005] In light of the foregoing, there is a need for the Rapid soil nutrient detection system for on-site applications that overcomes problems prevalent in the prior art.
OBJECTS OF THE INVENTION:
[0006] Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
[0007] The principal object of the present invention is to overcome the disadvantages of the prior art by providing the Rapid soil nutrient detection system for on-site applications.
[0008] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that provides a fast, field-deployable soil detection system addressing several important issues discussed in the background section.
[0009] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that advances test sensitivity and specificity through the marriage of chemical reactions detection (which detects the presence of a nutrient by looking for the presence (total as well as available).
[0010] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that utilizes electricity, a pipette, and a lab setup-free paper platform, making it ideal for immediate field application.
[0011] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that is provided with a smartphone app for reading results, which enables non-specialist users to receive clear, instant soil quality information and automatically report data to soil health networks.
[0012] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that are secure, with processes incorporated that annihilate toxic material on completion of analysis.
[0013] Another object of the present invention is to provide the Rapid soil nutrient detection system for on-site applications that leaves behind the conventional drawbacks of conventional soil testing by making it quicker, easier, safer, and more accessible, offering assured soil quality monitoring to everyone, everywhere.
[0014] Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY OF THE INVENTION:
[0015] The present invention provides a Rapid soil nutrient detection system for on-site applications.
[0016] The present invention is an easy, field-portable soil test kit so that individuals can test whether their soil is nutritionally rich. It is particularly convenient where soil testing is not readily available or there is no lab and electricity, i.e., in remote villages, hilly areas, or greenhouse soil-based experiments. The goal is to enable individuals to detect nutrient status (macro as well as micro) in their soils without equipment or knowledge. Millions of farmers worldwide apply both macro and micronutrients without knowing the soil's nutrient status. They because a severe buildup of specific nutrients in the soil, while some nutrients become depleted, leading to a nutritional imbalance. Analysis of soil nutrition typically takes a long time, often days, and requires a special laboratory, skilled technicians, and costly apparatus. Waiting time is crucial, as the farmer must sow seeds on time; otherwise, late sowing results in low productivity, leading to a financial burden on the farmer.
[0017] This invention is much quicker and easier. It uses a sheet of paper containing special chemicals that trap the soil solution and identify the amount of nutrients. One adds a soil water sample to the paper, which then flows through narrow channels. The channels contain dry chemicals that become wet when water enters them. As the water passes through the strip, these chemicals will automatically do a few things: capture the dissolved nutrients, conduct some specialized chemical material analysis, and deposit a visible indicator if they find something noteworthy. The result is a color change or a very low-order strip lighting. Creating a simplified reading, a cell phone application can read the strip using the phone camera. The device receives the signal and sends a message to the user, informing them whether to apply a particular fertilizer (macro/micro nutrient) to the soil. It even suggests immediate action depending on the nutrient level and location. The biggest plus of the device is that brilliance, speed, and convenience have all been put into one. It provides results within an hour, is portable to any place in the pocket, and is machine less and wireless. It features safety mechanisms that clean up after each test, ensuring no residue remains. The strips may be offered for various nutrients, and customers can choose to replace them at intervals with the same base unit, making it a cost-effective option. The technology is accessible to families residing in remote areas or those who are far away from the soil testing laboratory facilities, enabling both private and government officials to monitor real-time soil nutritional quality. It is a democratizing means of putting control of their soil safety into individuals' hands, thereby ensuring healthy soils. It is no longer confined to a lab, and it can instantly and accurately tests soils, accessible to anyone, anywhere.
[0018] The originality of this invention lies in its ability to combine potent concepts into a single, portable, and user-friendly device as it enables any individual, whether a trained scientist or a villager from a far-flung village, to detect soil nutritional status quickly and accurately. Although there are other machines to perform soil analysis, none bring together many essential qualities in one, simple-to-use strip that does not require electricity, lab tools, or professional knowledge. This is not just a new gadget; this is a better, more complete solution to real soil testing problems.
[0019] The present invention combines two forms of soil detection tests in one test: one for macro nutrients and another for micro nutrients. Most field tests have used one of these forms (mainly macro nutrients), failing to identify micro nutrients accurately or creating false positives. By combining both techniques into a single strip, this invention makes the test far more sensitive and precise. It can detect even trace amounts of nutrients in soil that other tests cannot detect. The device has a further innovative feature: a paper system with "channels" to direct the soil solution sample automatically through all test stages. Dry chemicals are incorporated within the paper at micro locations. When the soil water sample is deposited, it gets directed automatically down the strip—no buttons, no wires—triggering each stage in sequence. All the testing is smooth and relatively simple for non-scientists and non-clinical individuals.
[0020] Also new is how this test regulates heat. Unlike other tests that require equipment to maintain a set temperature, this one utilizes special materials that begin heating automatically upon test initiation. This new use of materials makes it possible for the test to be given where electricity and equipment are unavailable, only by the naturally generated heat of the test itself. The most significant improvement is in smartphone compatibility. The test includes a printed reference color scale, such as an integral color ruler, allowing for easy reading of the strip's colors using a cell phone application. The app considers parameters like light or camera sensor performance, providing sharp response and even alerts, e.g., "Good Quality" or "Poor Quality-need action." The app also measures time, geolocation, and outcome, which allows public agricultural officials to look at soil nutrition status in real time from numerous geographies.
[0021] Most importantly, the strip is rendered safe and easy to use following the test. It has sections that clean any leftover chemical or particle, and therefore are less likely to mix with another soil sample when used. Overall, the innovative aspect of this invention is that it unifies accuracy, user-friendliness, safety, and computer sophistication into one piece of equipment that no other water test has ever been able to accomplish as a whole. It is not infinitely improved; it is one giant leap towards perfect soil nutrition testing accessibility for all locations everywhere.
BRIEF DESCRIPTION OF DRAWINGS:
[0022] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
[0023] Figure 1: Battery-operated handheld reader device;
[0024] Figure 2: A test strip showing different regions/channels;
[0025] Figure 3: The handheld device showing the UV light lamp; and
[0026] Figure 4: A test strip showing different components.
DETAILED DESCRIPTION OF DRAWINGS:
[0027] While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and the detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim.
[0028] As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one” and the word “plurality” means “one or more” unless otherwise mentioned. Furthermore, the terminology and phraseology used herein are solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers, or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles, and the like are included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention.
[0029] In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase “comprising”, it is understood that we also contemplate the same composition, element, or group of elements with transitional phrases “consisting of”, “consisting”, “selected from the group of consisting of, “including”, or “is” preceding the recitation of the composition, element or group of elements and vice versa.
[0030] The present invention is described hereinafter by various embodiments with reference to the accompanying drawing, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only and are not intended to limit the scope of the claims. In addition, several materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary and are not intended to limit the scope of the invention.
[0031] The present invention provides Rapid soil nutrient detection system for on-site applications.
[0032] Soil is a primary source of nutrients required by plants for growth, and the three primary nutrients are nitrogen (N), phosphorus (P), and potassium. Together, they form the NPK trinity. Calcium, magnesium, and sulfur are vital nutrients. Plants also require trace elements, including Fe, Mn, Zn, Cu, Bo, and Mo. The role of these nutrients in plant growth is complex and indispensable for growth and development. Availability of nutrients in balanced amounts remains one of the longest-standing and pressing global soil and plant health challenges, especially in poor / nutritionally exhausted soils, degraded soils, mountain soils, rural, and remote field areas. These areas have no infrastructure, local or central testing facilities, or functional facilities. Farmers are therefore subjected to plantation or seed sowing without having any idea of their field's nutritional quality and status. Deficiency of available nutrients in soil leads to poor plant growth, yield, and food quality. Consuming nutritionally insufficient crops causes nutrient-related health issues among consumers. The gold standard for diagnosing soil health is to take soil samples and analyze them in laboratory centers that utilize the conventional method or new instruments. Though time-consuming, ranging from several hours to a few days before presenting the results, they are also costly. They involve sophisticated equipment, highly trained and experienced laboratory technicians with significant training, and specialized laboratory facilities that are specifically designed for this purpose. These conditions render it impossible to employ such methods for testing in most terrains where immediate, fast soil testing is required, e.g., rural areas, distant and isolated zones, and mountainous locations. Due to such limitations, scientists and engineers have achieved remarkable new capabilities with new field-portable soil analysis technologies. The most promising new technologies being developed are chemical test-based technologies and paper microfluidic devices. These emerging technologies draw on the science of microfluidics, in which liquid flows through channels of infinitesimally narrow cross-sections on paper or otherwise to perform complex chemical assays without electricity, trained technical personnel, or pipettes. Low cost and minimalism mean being deployable in massive numbers in the field. Also, specific chemical-based techniques can be incorporated directly within such paper-based systems to allow detection of trace and excess amounts of macro and micro nutrients, even without the incorporation of conventional bulky laboratory instruments. Some analysis steps are performed within a single, very tiny, closed device, and such devices are extremely time- and complexity-effective for detecting both macro and micro nutrients. Others provide mobile phone application support in visually administering tests and real-time reporting of findings into soil health surveillance systems. The integration of technology, high-end fluid control, inexpensive materials, and high-end chemical detection technologies has enabled the placement of low-cost, easy-to-use portable soil analysis technology that can potentially transform soil nutritional health practice among isolated, rural, and far-flung populations. These emerging technologies have the potential to democratize soil testing, enabling farmers to quickly assess their soil's nutrition status and avoid applying excess chemical fertilizers, thereby saving the economic exchequer and preventing nutrient imbalances. Among the breakthrough portable diagnostic technologies is the development of an integrated single-use macro and micro nutrients detection paper-based device. This new platform represents a significant leap forward in simplifying bulky, power-based, and costly machine processes, even in low-resource settings. The classical processes of soil nutrient detection are typically based on chemical analysis and machine detection. All these various steps involve reagents, energy, precise equipment, and trained personnel, none of which are available in field conditions or outstations in most cases. Paper-based integrated device eliminates all such constraints by integrating all the components into a small, user-friendly, self-contained diagnostic device. In the case of soil nitrogen assessment, it normally involves figuring out the quantity of nitrogen in a soil sample, which is critical to comprehending the fertility of the soil and plant growth. The most frequent procedures are the Kjeldahl and Dumas methods. These methods include the digestion of the soil samples to convert organic nitrogen to ammonia, which is then assessed using titration or other analytical techniques. The phosphorus in soil is measured after a series of chemical reactions, and color development detection using a spectrophotometer. The proposed paper technique uses lateral flow assay (LFA) technology to offer on-site and immediate visual presentation of test results, like a pregnancy test, that users can self-read without any special training beyond that needed for the general public. Visual markers make user error impossible and enable test results to be readable without special instrumentation. In addition, the test itself is easy; users need to insert a sample and start the reaction in only a few steps, so even those without a laboratory science experience can use it.
[0033] The product has also been highly sensitive and specific in detecting micronutrients, which are present in soil in low amounts. For example, in validation testing, it would be able to detect Fe, Zn, Mo, Cu, Mg, Mn at a low level of sensitivity. Notably, the assay performed optimally even in all types of soils of varied agro-climatic zones, and was rugged and acceptable for routine application. Also, the whole process from sample introduction to result interpretation is accomplished within one hour, and rapid turnaround is essential in estimating soil health and farmers' concerns. The frugal diagnostic device intersects frugal innovation, microfluidics, and chemical technology. The device is disposable, low-cost, and handheld; therefore, it is the most desirable device for decentralized testing. In rural, distant, isolated, and hilly regions, such organized systems could potentially enable farmers to detect and address soil nutritional status before sowing/planting crops in nutritionally poor soil, or to apply more fertilizers in nutritionally rich soil.
[0034] Another innovation in field-deployable diagnostics is the creation of a paper-based chemical enrichment platform as a field-deployable platform for the rapid and reliable detection of nutrients in soil in remote or resource-constrained locations. This platform combines the best chemical technology, microfluidics, and mobile electronics to provide a cost- and energy-efficient diagnosis platform that considerably narrows the soil sample collection-to-result interpretation time gap. Thus, this platform is an evolutionary leap for off-lab real-time soil health status and management. The device comprises a battery-powered miniaturized all-in-one reader and a paper-based enrichment chip. The enrichment chip is employed to recover macro and micro nutrients from diverse types of soil samples. The chip utilizes proprietary paper matrices that capture the macro and micro nutrients and eliminate the inhibitors and contaminants to produce a highly purified nutrient chemical form for detection. Its simplicity makes the chip light, inexpensive, and simple to mass-produce, a gigantic advantage in the case of soil nutritional health management mass deployment. The sample is inserted into the enrichment chip and read. The user performs the whole nutrient analysis process using various chemical processes. Reactions do not undergo heating, as carried out in labs; therefore, the whole detection process can be performed at a fixed temperature provided by the reader. Battery power renders the instrument completely grid electricity independent. It can thus be used in off-grid, rural areas or distant zones where standard laboratory equipment would be impractical or even impossible.
[0035] This is an electricity-free handheld test strip to detect nutrients in soil samples through capillary-based microfluidic technology quickly. This image depicts a low-cost, deployable, accessible soil detection system for nutrients by passive paper-based microfluidics and smartphone-based digital interpretation. The disposable, easy-to-use, low-cost system makes water testing accessible and allows early detection of nutrients in emergency or resource-poor settings. This point-of-care soil quality test strip offers rapid, inexpensive, and reproducible soil nutrient status determination without the need for a laboratory. A mobile phone application offers increased reliability, result interpretation, and geotagged data transfer for soil health surveillance. Each labelled feature represents a key functional area of the test device. Figure 1 shows the handheld reader device, which is a battery-operated instrument, onto which the nitrocellulose strip is placed.
[0036] Figure 1 shows Battery-operated handheld reader device, onto which the test paper/nitrocellulose strip is placed in the slot [1], grooves for test strip slot [2], which correctly hold the test strip; soil water sample loading tray slot [3], where the soil water sample is poured.
[0037] Figure 2 shows A test strip [4] showing different regions/channels, onto which the soil water sample flows uniformly in one direction due to the capillary action.
[0038] The test strip is placed in the slot on the upper surface of the handheld device. It can be easily placed over the device and removed with no trouble.
[0039] A drop or small amount of the soil solution sample (1–3 drops) is placed in the top section. This triggers capillary flow through pre-formed microfluidic channels within the paper. This section provides reliable wicking to downstream detection modules for easy sample delivery. This is done to initiate the diagnostic process. Initiates capillary-driven fluid migration on the paper surface. The material exhibits uniform wicking and does not spill over.
[0040] Figure 3 shows the handheld device showing the UV light lamp, emitting UV rays [5], which is a battery-operated lamp.
[0041] When the UV lamp glows, the fluorescent color of the completed test reaction on the test strip becomes visible, which is not visible to the naked eye. To observe the color change (fluorescent color), a test strip is required to be kept in the device slot.
[0042] Figure 4 shows A test strip showing different components, sample loading tray [3], dropper for adding the test sample [6], sample loader and distributor slot [7], channels for equal sample distribution [8], detection lines [9], conjugate pad [10], primary chemicals [11], secondary chemicals [12], dried reagents [13], test line [14], control line [15], absorbent pad [16]
[0043] As shown in Figure 4, the procedure is initiated by placing a sample of soil water in the sample distributor slot and loader [7]. The sample can be obtained from a calibrated dropper, micropipette, or from a pre-prepared vial, depending on conditions at the site as required and at the operator's discretion. When used, the test sample is drawn into the strip by capillary action, a motor-independent transport of fluid that does not require the implementation of external pumping systems and allows for field application in low-resource environments. The front fluid descends the strip to strike each of the conjugate pads with pre-immobilized reagents [11, 12, 13] in succession. The path of sample migration is shown in Figure 4 using a green arrow. Where the analyte target is present in the sample, chemical interaction or specific binding between the analyte and the reagent conjugates occurs. This may be antigen–antibody (in the case of immunoassays) or ligand–metal chelation (in the case of nutrient-specific detection). Capture reacts to form a detectable complex that moves to the detection zone, where it is trapped by pre-coated complementary capture reagents present on the nitrocellulose membrane. Trapping results in a visible signal in the form of a color band or fluorescence emission upon the detection of the target analyte. It also consists of a control line to confirm the function of the assay and prevent false-negative results through procedural mistakes or improper sample migration. In the absence of an analyte present, no signal—or, at most, a very weak, sub-threshold signal—is detected in the detection zone. The assay is read by signal intensity and colorimetric contrast with the background membrane and provides a semi-quantitative or qualitative result based on the test design. Detection of the majority of analytes constitutes one of the key innovations of the device. The central part of the test strip contains colorimetric or fluorescence-based detection lanes pre-coated with reagents specific to an analyte and capable of quantifying macro- and micronutrients in soil water extracts. The major macronutrients are nitrogen (N), phosphorus (P), potassium (K), and sulfur (S), and secondary nutrients such as calcium (Ca) are also covered in longer versions of the strip. Detection chemistry differs among various classes of nutrients. For instance, Nitrogen can be detected using the Griess reagent, in which nitrate is reduced to nitrite and reacts with sulfanilamide to give a diazo compound with the resultant pink-red color. Phosphorus detection is commonly a molybdenum blue assay in which orthophosphate reacts with ammonium molybdate in an acid solution to produce a blue chromophore. Potassium detection can be achieved by precipitation with tetraphenylborate to provide a turbidity or light-scattering trace. Calcium and magnesium can be found using metallochromic indicators like Eriochrome Black T or calmagite, which have a clear change in color when complexed. There is also a fluorescence detection mode labeled with a fluorophore and reagents that allow for high sensitivity, particularly for trace micronutrients. The excitation and emission signals in this case are both quantified using a smartphone-based image system or a portable fluorescence reader. Every test lane on the strip is physically isolated to prevent reagent cross-talk and maintain the integrity of multi-analyte detection. If present, the target nutrient causes a chemical or biochemical reaction—e.g., pH change, complexation, or precipitation reaction—to take place, leading to a visible chromatic alteration or quantifiable fluorescence emission. For color-read results, the test can be read by eye, with a color change to a color reference chart that comes with the kit. For digital outputs, the test strip can be snapped by a smartphone application utilizing computer vision algorithms for the measurement of color intensity or fluorescence brightness. This enables enhanced reproducibility, semi-quantitative analysis, and cloud-stored data logging for soils over time monitoring. The benefits of this design include portability and mains independence, making it suitable for use in remote and impoverished rural agricultural areas. High-speed turnaround, frequently in a matter of minutes, enables rapid decision-making in nutrient management. Low cost of production, since reagents like nitrocellulose membranes, polymer supports, and colorimetric reagents are cheap and amenable to mass production. Ability to conduct several analyses, minimizing the use of separate individual tests to a minimum, and thereby saving resources. Facile integration with electronic technology by scientists, agronomists, and farmers to retain, transfer, and analyze results in the long term. The system thus reconciles simplicity in conventional lateral flow tests with contemporary digital interpretation methods to fill the gap between low-tech availability and high-tech precision agriculture. It has the potential to facilitate soil fertility diagnosis on site, increase fertilizer application efficiency, and support sustainable agriculture.
[0044] Reference ladder: There is also a reference ladder, which is a graduated combined intensity scale on a test strip and the detection area. It offers calibrated points of reference for quantitative analysis of signal intensity with allowance for illumination and smartphone camera variation. It is reproducible and precise across users and environments. It provides electronic or visual calibration. The paper strip is marked with solid printed fluorescence intensity bars or color scales near the test zone. Additionally, it enables smartphone applications and operators to calibrate the intensity of test results to known values, facilitating quantification. The benefits include its ability to adapt to environmental changes, such as variations in light or camera performance.
[0045] Dotted chambers: Strategically designed permeable paper strips are utilized as fluidic delays. Sample flow rates are controlled in these regions to provide valuable time for definite reactions, such as the interaction of nutrients and chemical reagents or color formation after reaction. Timing becomes crucial in proper signal generation in the following regions. Nitrogen, a key macronutrient for plant growth, can be measured using paper strip methods that test nitrate (NO₃⁻) or ammonium (NH₄⁺) forms. The strips are frequently coated with chemicals that cause colorimetric reactions with these nitrogen compounds.. The primary outcome is that it offers multi-step processes without user intervention or electronics.
[0046] Waste Reservoir: A terminal fluid absorption pad Figure 4 [16] that catches the expended soil water sample upon completing the whole test course. It prevents backflow, eliminates mixing hazards, and provides safety by safely holding potentially toxic chemical waste. Its primary function is to hold and inactivate excess fluid, and act as a sample reservoir when the test is complete. This is an absorbent tip at the end of the strip, which prevents contamination or reverse flow. It may contain chemicals to neutralize residual nutrients, and offers cleanliness and biosafety when field-used and discarded.
[0047] Blister Reagent Pack: Small sealed packages are inserted within the strip with dry or lyophilized reagents (e.g., chemicals, elements, substances). They are finger-pressurizable or fluid-contact activatable and release contents into the flow stream to facilitate critical reactions like color development. Micro-compartments are placed strategically along the fluid path where important chemical interactions occur. These are chemical-reagent recognition, enzyme-substrate catalysis, or substrate amplification of the target nutrient. Its main function is to dispense dry reagents required at the right time. The test strip incorporates foil-sealed or membrane-sealed small packets. Activation occurs when the user presses or applies pressure to the perforated area during flow.
[0048] The main contents are: diverse chemicals, chelating agents, redox indicators, analytes, buffers or coloring agents, and specific elements for color development. The main advantage is that it provides elimination of storage constraints, room-temperature stability, and shelf-life increase.
[0049] Embedded Reaction Zones: Strategically designed permeable paper strips are utilized as fluidic delays. Sample flow rates are controlled in these regions to provide valuable time for definite reactions, such as chemical reactions and color development. The primary function is to enable a unique chemical reaction, which is carried out by hermetically sealed vessels by layering or impregnating reagents in paper. The example reactions could be; substrate-nutrient reaction (e.g., for phosphorus assessment, filter paper is infused with iron oxide (and sometimes aluminum oxide) to capture plant-available phosphorus), enzyme-substrate catalysis (e.g., detection of ammonia using urease), Ca and Mg detection (e.g., utilizing complexometric indicators which alter color when bind to these cations). The design can include thermal insulation or reaction buffers with dry state stabilization.
[0050] Colorimetric Calibration Ladder: A sequence of colored dots or gradient bars in a specified order that are integrated into the strip. It offers onboard calibration reference via smartphone app or visual contrast. It reduces the interpretation error due to the user's subjectivity or vagueness of ambient light. It normalizes test interpretation. The color gradations of colored dots or calibrated color gradations to expected signal intensity levels. It aids a user or phone application in assessing whether test signals indicate safe or dangerous levels of contamination. Its design is scaled for use in different light conditions—daylight, cloud, and indoor.
[0051] Embedded Stripes and Chambers (Microfluidic Flow Paths): Paper-based architectures with hydrophobic and hydrophilic zones to guide sequential fluid flow in all functional regions required (Figure 4, green arrow direction). Divided reaction space, signal formation, and reagent release are all coordinated within a confined system using patterned and stacked routes. Its function is to control and direct sample flow. The test strip is structured with hydrophilic channels and hydrophobic barriers (wax printing, laser etching, or photolithography), which guides the sample in sequence through detection, reaction, and calibration zones, and protects from cross-reactivity of reagents.
[0052] It facilitates multiplexing analysis for many nutrients in one step, and the main innovation is that it allows dual-format testing—macro as well as micro, in one test strip.
[0053] Multifunctional result readout is one of the greatest strengths of this platform. The results are readily observable to the naked eye visually by colorimetric markers in the zone of reaction, providing an instantaneous and simple observation of the test result. Likewise, the instrument is also provided as a smartphone app to quantify further or read out digitally. The software can capture an image of the test strip, read the intensity of color, and give a compact result as "Positive" or "Negative." The software can capture metadata like GPS location, time, and sample type for easy insertion into soil health surveillance systems and real-time, simple nutrient status monitoring. Its ease, ruggedness, and speed render it a precious asset during point-of-need diagnosis in resource-limited soil health facilities or at the time of sowing. Decentralized testing and enabling non-expert operation, a paper-based platform for enrichment bridges central gaps in soil nutrient health detection and brings necessary diagnostics to the point of need.
[0054] Paper biosensors are a novel and emerging diagnostic tool, handy for detecting diverse nutrients in emergency and field conditions. Their capacity for quick, precise, and user-friendly measurements with minimal requirements for advanced laboratory equipment has made them of intense interest, particularly in low-resource settings and immediate emergencies. LFAs are the most common platform of several paper-based biosensors because they are easy to use, less expensive, and versatile toward many chemical targets such as NPK, micro elements (Fe, Zn, Co, Mg, etc.). Lateral flow assays are principle-based on the capillary action where the soil solution test sample is propelled along a paper strip, typically in the form of a nitrocellulose membrane, without requiring an external power source or pumps. The standard LFA strip has some inherent components that are utilized together to analyze the sample and provide output. Components consist of a sample pad, conjugate pad, nitrocellulose membrane upon which detection lines are printed, and a terminal absorbent pad. The sample will start migrating down the strip after being applied to the sample pad. Chemicals, or surfactants, will be on the sample pad to condition the sample and ensure good flow. The test sample then proceeds to the conjugate pad, where it interacts with dried reagents in the form of chemicals, redox reagents, chelating agents, or oxidants. To enable LFAs to detect a particular nutrient, a target reagent is chosen and identified using complementary probes, which become bound only in the presence of the particular material of the soil water sample. When the target is present in the sample, it complexes with the probe-marker and forms a detectable complex, which will continue to flow along. When it arrives at the test region of the nitrocellulose membrane, the complex is stopped by bound secondary chemicals or probes. Visible line development, the cause of the positive test, is that which is formed. The control line confirms that the test is proper by attaching any excess conjugates in such a manner where the assay is correct. The form of the test enables the detection and semi-quantitation of analytes in terms of the intensity of lines.
[0055] LFAs have hence proved essential in several diagnostic uses, from infectious disease diagnosis, environmental sample collection, food protection, and genetic analysis. Their principal benefits include no or negligible pre-sample preparation, quick turnaround time, room temperature stability, and simple lay interpretation. This is why they can find potential applications in different environments like soil health analysis in garden soil, also rural, remote, and distinct places. LFA integration with smartphone-based testing is also gaining popularity, where digital readout, recording, and distance reporting to health authorities are enabled. Overall, LFAs represent the cornerstone pillar of paper-based biosensor science. Their portability and ease of use provide a foundation to democratize diagnosis and enable the timely detection of soil nutrient status at any point on the globe.
[0056] One such innovation with the integration of point-of-care (POC) diagnostics with greater functionality, convenience, and portability is the use of paper analytical devices (PADs) in cell phones. The new integration provides the solution to the first-order requirement of low-cost, accurate, and decentralized diagnostic devices, especially for those soil nutrition barring the use of conventional laboratory devices. A good example of such integration includes the development of a paper analytical device based on paper that is capable of performing dual-mode detection—fluorescence and colorimetric—of redox reaction, chelating agents, analytes or enzyme activity. It involves several chemical processes and can be used as a nutrient biomarker. Because of this, detection needs to be effective and quick in the field and diverse environmental settings. The chip utilizes cellulose-based paper as a cheap and readily available substrate material that is highly well established to be controllable by capillary fluid flow and bioreagent compatible. Wax printing, a simple, low-cost, and high-throughput fabrication technique, is employed by the chip to fabricate the microfluidic channels of the paper. Hydrophobic barriers govern fluid sample and reagent flow along diverging paths to control reaction and interaction in targeted locations. It enables the device to perform multiple chemical assay steps sequentially and reproducibly without sophisticated equipment and human expertise. When in use, the user deposits a liquid specimen onto the pre-scored sample zone on the device. The specimen is driven through microfluidic channels into reagent-infused spaces. The reagents selectively bind to substrate upon detecting the presence of the nutrient in the sample. The substrate reaction leads to the detectability of a detectable change by two independent but complementary modalities: colorimetry and fluorescence. In colorimetric mode, the detection area is pigmented at visible wavelengths, which can be easily seen with the naked eye. Whereas the device in fluorescent mode, upon UV light excitation, will fluoresce if the substrate acts optimally, the assay is still concentration-sensitive to analyte variation.
[0057] Besides quantification, the smartphone is incorporated into the paper-based sensor for broader availability. The smartphone is a generic platform that records the colorimetric or fluorescence signal as an image with its built-in camera. Advanced software programs on cell phones transform the images to determine the signal intensity and correlate it to the activity level of the substrate in the sample. Since it not only facilitates the collection and analysis of data but also includes geotagging, data logging, remote diagnosis, and real-time reporting to soil scientists or soil nutrient health repositories, with the integration of paper devices and mobiles being one of the success stories of the robust wave of digital health and decentralized diagnosis. It diminishes dependency on fixed labs and takes high-quality analytical ability to the site of need—garden, fields, rural areas, or remote areas. Dual-mode detection also enhances reliability by providing instant visual confirmation, supplemented by more precise analytical measurements, which in turn decreases false positives. Smartphone PADs, such as the substrate detector, are thereby a convergence of science made portable, mobile, and people-enabling design. They are revolutionizing data collection, analysis, and application in diagnosis to make soil health care more responsive, inclusive, and evidence-based.
[0058] The new paper-based test assay presents a low-cost, easy, and rapid alternative, particularly for field testing and point-of-care testing. Nutrient assay features a lateral flow nitrocellulose membrane substrate that facilitates capillary migration of the sample through pre-loaded test sites. Specific reagents for the substrate treat the strip, and on a positive result, deliver a colored visible output. The density of subsequent colors increases with the rise in concentration of the nutrient sample and also contributes to naked-eye semi-quantitative visible interpretation. The system's effectiveness is enhanced by its smartphone app, which achieves the highest possible precision and test convenience. The participants, upon completing the assay, take a picture of the test strip through their cell phone. The computer program then processes the image, measuring the color intensity using sophisticated image processing routines to compensate for extraneous light, camera, and other environmental factors. This yields a less subjective, reproducible, and more accurate measurement of nutrient level compared to crude visual estimation. Mobile applications can also store, analyze, and share information with a simple button click. The test result can be tagged with metadata, such as time, location (with GPS), and field location, making it more useful for soil health response and nutritional surveillance. It enables real-time mapping of nutrient deficiency and excess hotspots, allowing for the timely deployment of soil scientists' assets. Above all else, the system's portability and ease make it accessible such that even an unknowledgeable technical person or a nonspecialist can employ it. Thus, its availability and penetration are significantly enhanced. The quantification-augmented and portable paper-based chemical assay for detecting nutrients is a step towards democratizing diagnostics. It combines the low cost and ease of a lateral flow assay with the benefit of digital technology to create a scalable, field-deployable, handheld device that will enhance nutrient level detection and management in most crop field settings.
[0059] Paper-based microfluidic devices have also experienced explosive development in recent years, extending their applications beyond conventional clinical diagnostics to priority areas such as environmental monitoring. Perhaps the most significant application is identifying soil nutrient status in diverse agro—ecosystems, such as isolated hilly areas, which serves as a valuable marker for the possible presence of soil nutrients. One of the most significant achievements in the area has been developing a handheld paper-based biosensor system for real-time on-farm nutrients monitoring, especially for fresh produce farms where immediate and effective action is vital. A paper-based biosensor system has been developed as an off-the-shelf, fully integrated diagnostic kit that needs little training and no laboratory equipment. The product combines some of the most critical components into one package: a drop generator to facilitate sample preparation and handling, an imaging and heat module to facilitate and monitor chemical reaction, and house paper-based biosensors as the detection substrate. These devices operate within a synergistic system together to yield sensitive and precise results in the time interval of approximately an hour from sampling to readout. It starts with sampling the surface rinse samples of fruits and vegetables, which are then fed into the drop generator. The module offers reproducible and repeatable liquid sample deposition onto paper-based biosensors. The biosensors contain dry reagents, i.e., fluorometric or colorimetric substrates, which turn colored on being brought into contact with specific chemical, analyte, or enzymatic activity or redox indicators in soil, e.g., Nessler’s reagent and nitrogen estimation. When they contact soil dissolved nutrients, the substrates turn colored or exhibit a fluorescent response, a clear, readable sign. The heating and imaging module will enhance reaction kinetics and biosensor sensitivity by providing optimal conditions for analyte activity and high-resolution imaging.
[0060] Low-power battery operation is an everyday-use battery that functions as a rugged, field-and-outdoors-capable unit. Images captured during assay time can be visually examined for real-time analysis or via a locally co-located smartphone program providing signal intensity and normalizing response reports. This machine promises to enable prompt decision-making among farmers by allowing them to determine soil health and decide on crop sowing suitability based on the soil's nutrient status. Above all, low costs and simplicity will make it feasible for poor-resource settings and small-scale farmers and producers who cannot afford lab facilities at the center. Its application enables timely monitoring and diagnosis of soil nutrition health. By enabling in-situ on-site localized detection of soil nutrients, this paper-based microfluidic biosensor enables farmers to react immediately following knowing the soil health status, implement effective countermeasures promptly, and establish a sustainable cropping system. Finally, these technologies highlight the additional importance of paper-based diagnostics in ensuring soil health across agricultural and environmental applications. These paper-based microfluidic device technologies, especially combined with smartphone technology, are a paradigm shift in agro-ecosystem diagnostic capability, and specifically in field soil quality nutrients detection capability. The conventional nutrient detection methods in soil sources generally require high-technology laboratory equipment, expert technicians, and lengthy processing time, none of which are found in extensive rural or resource-limited areas. Paper microfluidic devices overcome all these limitations using inexpensive, portable, and simple modalities that are sensitive and specific.
[0061] Their most fascinating feature is the dual mode of detection: macro as well as micro nutrient analysis. Paper platform integration with such methodologies has a number of benefits. Paper as a platform is inexpensive, lightweight, and biodegradable, enabling capillary-driven fluid movement without needing an outside power source. It thus makes the whole system cost-effective and sustainable. Other than that, paper-based systems also lend themselves well to being easily mass-produced, and therefore, production costs can be proportionally minimal, making mass deployment easily possible through farmers' agricultural programs or in a soil fertility management scenario.
[0062] Smartphone connectivity further adds to the device's amenity and convenience. Since they are equipped with cameras and sensors, smartphones will be able to quantify colorimetric or fluorescence from paper-based assays, quantify amounts, and transmit data to cloud storage or public health authorities in real time for surveillance. All tests through this connection will more likely be an instrument point of data in a large surveillance web, feeding data into early warning systems and evidence-based soil fertility health interventions. Besides, the machines can assist in conducting the walk test through steps that reduce error and require special training. With ease of mobility and fast turnaround time, the machines can easily find applications in rural regions where they are far away from district laboratory testing centers and in remote areas, where there is a need for soil fertility status. These are the types of circumstances where the capability to determine in seconds and with accuracy whether soil is healthy and can be used for quality and quantity production. Beyond nutrients, research even goes as far as to allow such devices to enhance their capability for detecting chemical contaminants such as heavy metals, pesticides, and xenobiotics to give a more complete characterization of soil quality. The union of paper microfluidic devices with cell phone technology is thus revolutionizing soil analysis management to monitor, manage, and safeguard their soils.
[0063] Sustained innovation and mass application of new technology for soil fertility testing, for example, paper microfluidic devices hybridized with cellular phone capability, can be the turning point for global campaigns against barren lands. Current soil analysis methods, although convenient, are inadequate in these settings due to their high cost, reliance on machinery, and time-consuming nature. Field-portable, low-cost, user-friendly detection kits can revolutionize things. By facilitating rapid and reproducible determination of nutrient status, third-generation analyzers facilitate easier public action. In contrast to their traditional lab-based counterparts, which would take days to provide information, point-of-use analyzers can provide decision-enabling information in hours or minutes. The equipment is simple to train on, and neighbors or local government employees can use it daily to determine soil nutritional status. Smartphones support increased performance and efficiency of the devices since they support digital presentation, software interpretation of data, and geotagging of pollution events. Data received on mobile phones can be relayed in real time to central data repositories, where governments and soil scientists can analyze trends, identify hotspots, and allocate resources more effectively. Moreover, applications of such technologies support long-term global health and environmental goals of the United Nations Sustainable Development Goal 2: end hunger, achieve food security and improved nutrition, and promote sustainable agriculture. The addition of research and application of innovative paper-based water analysis technology is, therefore, a feasible and attainable step toward preventing the incidence of world nutrition-derived disease. Briefly stated, the union of paper microfluidics and smartphone platforms is a paradigm shift towards field-deployable soil fertility analysis. The new union overcomes most of the conventional disadvantages of traditional lab-based analysis, including high operational costs, the need for highly skilled human resources, dependency on advanced hardware, and delays in obtaining soil sample reports. The above limitations have hitherto limited real-time quantification of soil quality, particularly in geographically remote, dispersed, or isolated hilly regions. Paper-based diagnostics enabled by mobile technology provide a rational, inexpensive, and scalable answer to such demand. Paper microfluidic devices are designed to carry out advanced chemical assays by miniature volumes of reagent and fluid in an expendable, biodegradable, and portable package. They are so well designed to generate and deliver that they are the most suitable option to utilize in the field where lab installation is not available or practical. The technology can identify a wide range of pens that would constitute nutritional status from low, medium, to high, thereby giving a correct reflection on soil nutrition status. Smartphone connectivity enhances the detection power of these devices in several key areas. Second, cell phones allow imaging, inspection, and recording of the visual output of the assays—e.g., fluorescence or colorimetric signals—through some apps. Apps can subsequently translate information through embedded algorithms and provide users with interpretable, real-time results. Second, GPS and connectivity allow test outputs to be geotagged and replicated into central databases, thus allowing real-time monitoring and mapping of soil fertility status. These electronic interfaces play a key role in facilitating timely intervention in soil health and planning for long-term intervention in resource management, leading to sustainable and high-quality agricultural produce. Advances in material science, biosensor engineering, and microcomputer miniaturization will further contribute to increasing the sensitivity, specificity, and shelf-life of these integrated systems in the future. There must also be space for innovative technologies, such as multiplexed testing capability (enabling the simultaneous testing of two or more nutrients), auto-sustaining paper-based sensors, and machine-based reading, which enhances accuracy and facilitates easy-to-understand instructions. They will expand the uses of the soil fertility test kit to serve as a routine monitoring tool, a shield against soil health decline, and an intervention tool for public nutrition-based health. Second, their broader implications align with global efforts to achieve global access to nutritionally improved food, as dictated by the United Nations Sustainable Development Goals. Easy access to demand-responsive and reliable soil quality testing, smartphone-readable paper-based microfluidic devices enable communities to become masters in their own right as soil resource custodians and enable well-informed local decision-making to evolve in situ. However, these technologies are less a technology development problem and more a paradigm shift problem in water safety provision and strategy. With each step taken in this research and development, these tools will become ever more important in the protection of public health through sustainable soil fertility management, restoration of the quality of derelict agricultural land, and the provision of nutritionally rich and healthy produce.
[0064] The disclosure has been described with reference to the accompanying embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.
[0065] The foregoing description of the specific embodiments so fully revealed 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 scope of the embodiments as described herein. , Claims:We Claim:
1) A portable soil nutrient detection system, the system comprising:
- a disposable paper-based microfluidic test strip having a plurality of hydrophilic flow channels defined by hydrophobic barriers;
- a sample loading region configured to receive a soil solution sample and initiate capillary-driven migration of the sample along the channels;
- at least one reaction zone containing dried chemical reagents adapted to react with one or more target macro- and micro-nutrients selected from the group consisting of nitrogen, phosphorus, potassium, sulphur, calcium, magnesium, iron, manganese, zinc, copper, boron, and molybdenum;
- a detection zone downstream of the reaction zone configured to produce a visually perceptible signal, colorimetric and/or fluorescent, indicative of the presence or concentration of the target nutrient(s);
- a control zone configured to verify test validity; and
- a handheld reader device configured to hold the test strip, provide controlled illumination including ultraviolet light, and optionally communicate with a mobile computing device to capture, process, and transmit test data.
2) The system as claimed in claim 1, wherein the test strip comprises multiple parallel or sequential flow channels, each containing reagents specific to a different nutrient, enabling simultaneous detection of macro- and micro-nutrients in a single assay.
3) The system as claimed in claim 1, wherein the reaction zone comprises embedded blister reagent packs containing lyophilized or sealed reagents configured to release upon finger pressure or sample contact.
4) The system as claimed in claim 1, wherein the test strip comprises a waste reservoir at a terminal end configured to absorb and retain residual sample fluid and neutralize potentially hazardous chemicals.
5) The system as claimed in claim 1, wherein the detection zone comprises an onboard reference ladder comprising a printed color gradient or fluorescence intensity scale for visual or electronic calibration of signal intensity.
6) The system as claimed in claim 1, wherein the paper-based microfluidic channels incorporate strategically designed fluidic delay chambers to control reaction time between the sample and reagents.
7) The system as claimed in claim 1, wherein the handheld reader device comprises a battery-operated light source configured to illuminate the detection zone for fluorescence excitation and visual signal enhancement.
8) The system as claimed in claim 1, wherein the system comprising a mobile computing device application configured to:
- capture an image of the detection zone;
- process the image to determine signal intensity and correlate the intensity to nutrient concentration;
- geotag, timestamp, and store test results; and
- transmit results to a remote soil health database or surveillance system.
9) The system as claimed in claim 1, wherein the paper-based test strip is fabricated via wax printing, photolithography, or laser etching to define hydrophobic barriers and patterned microfluidic pathways.
10) The system as claimed in claim 1, wherein the reagents in the reaction zone are selected from the group consisting of:
- colorimetric indicators for nitrate or ammonium nitrogen;
- iron oxide or aluminum oxide impregnated substrates for phosphorus capture;
- complexometric indicators for calcium or magnesium;
- chromogenic or fluorogenic chelating agents for transition metals; and
- enzyme-substrate pairs for nutrient-specific catalysis. 13. A method of detecting soil nutrients in the field, the method comprising:
- collecting a soil solution sample;
- applying the sample to the sample loading region of the test strip of claim 1;
- allowing the sample to migrate via capillary action through the reaction zone and detection zone;
- observing a visual signal and/or capturing the signal with a mobile device;
- processing the captured image to determine nutrient presence or concentration; and
- optionally transmitting results to a remote database for soil health monitoring.