4. DESCRIPTION
Field of invention
The first step in natural resource management is the natural resource assessment. Unless we know the extent of our natural resources, such as soil resources, the management strategy cannot be formulated. Considering biomass production function of soil, its nutrients are the most important resources, which deserve attention on priority. Optimization of fertilizer input management is one important option to conserve soil fertility to make it enable to produce biomass on sustainable basis. However, fertilizer production is an energy-intensive process. Hence, judicious application of fertilizer is also necessary to minimize its loss, thus conserving energy. The efficient use of fertilizer depends on the knowledge of availability of nutrients in the soil, which in turn depends on effective soil test.
The soil test is an important measure of the soil's ability to supply nutrient elements needed for good plant growth. Soils constantly undergo change. The quantity and availability of plant nutrient elements in the soil change as a result of removal by the growing or harvested crop, leaching, erosion, or the addition of fertilizer, manure or compost. The soil test reveals the current fertility status and provides the information necessary to maintain the optimum fertility conditions for the plants to be grown. The present invention relates to a digital Soil Test and Fertilizer Recommendation (STFR) meter which may be used as a self-diagnostic tool to analyze soil samples, and provide the necessary information to maintain the optimum fertility conditions for the plants to be grown.
Background of invention
At present we have about 500 soil testing laboratories throughout the country, which is not sufficient to cater the need of our farming community. Hence, there is a strong recommendation for setting up of more soil testing laboratories (STLs). To supplement such laboratories, development of soil testing kit is necessary, which will also boost up fanners participation. An in-depth constraint analysis of soil testing services in the existing STLs, are not being utilized up to their potential, one of the major reason being lack of voluntary participation by farmers in providing samples and receiving as well as implementing recommendations. Due to insufficient number, the STL staffs cannot reach the farmers regularly; instead expect the farmers to come to their Laboratories. Moreover, intensive cultivation in the last few decades have caused multinutrient deficiencies, particularly zinc, boron and sulphur which are serious drawbacks for potential crop production.
Prior art
It is well known that monitoring of agricultural crops is desirable to determine existing growing conditions so as to allow for improvement and maximization of yields. At present most of the soil test kits are based on visual comparison of colour chart, and obviously these tests are qualitative in nature. Moreover, fertilizer recommendation cannot be based on qualitative estimation. Portable colorimeter can be used for soil test purpose but no such instrument exists to give fertilizer recommendation based on soil test data. Moreover most of these colorimeters are imported and would be very costly proposition for an average farmer.
In the conventional soil test kit, the colour of the test solution is estimated approximately by visual comparison with a colour chart resulting variation in estimation from person to person, whereas in this digital soil test meter colour of the test solution is estimated scientifically and quantitatively by colorimeter which is much more accurate than visual comparison.
The invented Digital Soil Test and Fertilizer Recommendation (STFR) Meter is an essential component of a soil-test kit which is aimed to bridge this gap. An easy-to-use meter coupled with fertilizer recommendation generator has been invented, which can be used by educated farmers in villages with minimum training. The Digital STFR meter may be used as a self-diagnostic tool to gauze soil fertility and determine fertilizer recommendation based on soil test data.
Objective of the invention
1) The main objective of the present invention is to develop a soil test meter which can quantitatively estimate the available nutrient status of soil with respect to organic carbon, nitrate, phosphorus, potassium, sulphur, zinc and boron
2) Another objective of the present invention is to recommend fertilizer dose for selected crop and selected target yield based on the available nutrient status which will be calculated and displayed by the meter.
3) Yet another objective of the present invention is to develop a low cost and user friendly soil test and Fertilizer Recommendation meter.
Summary of the invention
The present disclosure is related to development of a low cost and user friendly soil test meter which can quantitatively estimate the available nutrient status of soil with respect to organic carbon, nitrate, phosphorus, potassium, sulphur, zinc and boron and more particularly predicting the fertilizer dose
requirement for selected crop and selected target yield based on the available nutrient status which will be calculated and displayed by the meter.
The digital embedded system instrument can estimate quantitatively available nutrients in soil such as organic carbon, nitrate, phosphorus, potassium, sulphur, zinc and boron. The available nutrient in soil is extracted with a reagent and a colour is developed in the extract with addition of another reagent. The colour intensity which is proportional to the amount of nutrient extracted is measured by this STFR meter. The digital soil test meter can estimate colour of the test solution scientifically and quantitatively by colorimeter which is much more accurate than visual comparison as performed earlier. This is a low cost and user friendly instrument, and all the seven tests mentioned can be done at a very reasonable rate.
Detailed description of the invention
The digital Soil Test and Fertilizer Recommendation (STFR) meter of the present invention can be used as a self-diagnostic tool to analyze soil samples scientifically and quantitatively by colorimeter, and provide the necessary information to maintain the optimum fertility conditions for the plants to be grown.
The instrument is rectangular in shape and the body is made up of plastic. The electronic component of the instrument consists of a Microcontroller ATMega 32, Light Dependent Resistors (LDR), Light Emittimg Diode (LED), Liquid Crystal Display (LCD) and Program Header. The body of the instrument includes a sample holder to hold the soil sample extract dissolved in a reagent, a display to observe the result, and beneath the display screen there are five operating buttons marked UP, DOWN, ESC, ENTER and RESET. The UP and DOWN button is used to browse the instrument and ENTER button is used to select the nutrient to be measured. The ESC button is used to go to the previous menu and RESET button is used to go to the opening menu. There are four screws at the bottom which can be opened to load a 9V dry cell. The meter can also run with a 9-12 V AC adapter. After estimating all the nutrients, fertilizer recommendation can be obtained for a selected crop and a selected yield target from the FERTILIZER DOSE item of the menu. The Digital Soil Test and Fertilizer Recommendation meter is basically a programmable colorimeter.
Electronic components: The electronic components of the digital Soil Test and Fertilizer Recommendation (STFR) meter include the following:
Microcontroller ATMega 32: Microcontroller has been programmed by C language using legally free tool chain from GNU General Public Licence Software. This is the main component having 32 KB memory acting as:
(a) Analogue to Digital Conversion
(b) Arithmetic Calculation and other program implementation
(c) Switch ON/OFF of light source

1) Light Dependent Resistors(LDR): This is the sensor for light intensity which produces voltage drop in the circuit
2) Light Emitting Diode (LED): These are three sources of light viz., Red, Green and Blue which is put ON and OFF electronically by the microcontroller as according to the program written on it.
3) Liquid Crystal Display(LCD): This is 2 x 16 character display unit to view the observation
4) Program Header: Through this the microcontroller is programmed by a computer through a cable connected to its parallel port/USB port.
The function of the Digital Soil Test and Fertilizer Recommendation meter can be described in the following steps.
1) Colour sensing unit. The soil extract after extracting soil with an extractant is mixed with a colouring reagent to produce a colour which is then placed in the sample holder of this meter. The meter then senses the colour intensity and compare with that of a standard and a blank solution and produces a net voltage.
2) Voltage measuring unit: This measures the voltage produced by the colour sensing unit
3) Data processing unit: This system calculates and process the voltage data and convert to available nutrient value in accordance with the program written on it which then are displayed on the LCD display and are stored in the memory
4) Fertilizer recommendation system: This system calculates the required fertilizer dose, taking the stored value of available nutrients and the input given by the user on crop and yield required
BRIEF DESCRIPTION OF THE DRAWING AND GRAPHS
FIG 1 Shows the perspective view of STFR meter which includes
1) Sample holder
2) LCD Display
3) Five press buttons:
a. UP button
b. DOWN button
c. ENTER button
d. ESC button and
e. RESET button
4) Power Switch which can be used for ON/OFF
Graphs 1-7 represent regression analysis done between conventional method and STFR method.
GRAPH 1 shows STFR standard curves of organic carbon
GRAPH 2 shows STFR standard curves of Phosphorus
GRAPH 3 shows STFR standard curves of sulphur
GRAPH 4 shows STFR standard curves of Boron
GRAPH 5 shows STFR standard curves of Zinc
GRAPH 6 shows STFR standard curves of Nitrate and
GRAPH 7 shows STFR standard curves of Potassium
Table 1 List of Reagents
(Table Removed)
Detail process of analyzing a soil sample:
1) Nutrient extraction and colour development: A definite amount of soil sample is shaken with an
extracting reagent as shown in table 1. Another reagent (colour developing reagent) is added to the extract as shown in table 1 and a colour is developed. To estimate the amount of nutrient present in the soil, the intensity of the colour is measured by the STFR meter
2) Measurement of the colour intensity and the amount of nutrients by STFR meter: The meter
can be operated with the Menu button. The options in the menu include the following: -
a) ORGANIC CARBON (N)
b) NITRATE
c) PHOSPHOROUS
d) POTASSIUM
e) SULPHUR
f) ZINC
g) BORON
h) FERTILIZER DOSE
The button functions as follows:
i. The UP and DOWN button is used to go to the corresponding menu of nutrient in the opening menu.
ii. The ENTER button is used to select the required nutrient.
iii. The display shows the command "PUT Blank" which denotes to put a blank solution that is the solution where no nutrient is present and then press ENTER button. The meter will note down the blank reading and display "PUT STANDARD SOLUTION". Then put a standard solution which has been prepared by adding a known amount of nutrient and develop a colour, then press ENTER button. The instrument will note down the reading, save it and show "PUT SAMPLE" in the display. Then the coloured solution sample is placed and press ENTER button. The meter will now show in the display the available nutrient present in the sample. The meter will save this amount and will be utilized later to calculate fertilizer required for a particular crop and the yield required. This will be stored in the memory till the instrument is RESET or put off.
iv. For selecting another nutrient press ESC button and go to previous menu. Once the second nutrient is selected, the same procedure is followed as in case of the first one to know its amount present in the soil.
v. When estimation of all the seven nutrients are over go to the "FERTILIZER DOSE menu and ENTER. The display will show the menu for crop as mentioned below:
SELECT WHEAT SELECT MAIZE
With the help of UP, DOWN and ENTER key the desired crop is selected. The meter will show the menu of yield targets for the selected crop.
TARGET=40 TARGET=50 TARGET=60
The desired yield target for the crop is selected with the help of UP, DOWN and ENTER key. The display shows the amount of urea dose (for nitrogen), amount of diammonium phosphate (DAP) dose (for phosphorus) and amount of muriate of potash (MOP) dose (for potassium) and if required the dose of other nutrients. Similarly for other crops also the dose can be obtained.
Working Example
Different types of soils were taken, viz red, black and alluvial, and estimated (1) organic carbon (2) Nitrate, (3) Phosphorus (4) potassium (5) Sulphur (6) Boron and (7) zinc by both conventional method (spectrophotometer) and STFR meter. Regression analysis was done between conventional method and STFR method. Significant relationships have been obtained between conventional method and STFR method. These relationships and the respective STFR standard curves have been shown in Graph l(OC: organic carbon), Graph 2(Phosphorus), Graph 3(sulphur), Graph 4(Boron), Graph 5(Zinc), Graph 6(Nitrate) and Graph 7(Potassium).

I/We claim:
1. A digital embedded system instrument comprising:
(a) A sample holder
(b) LCD Display
(c) Five operating buttons: a) UP button b) DOWN button c) ENTER button d) ESC button and e) RESET button and
(d) Power Switch which can be used for ON/OFF

2. The digital embedded system instrument according to claim 1 wherein, the said digital embedded system instrument is a Soil Test Fertilizer Recommendation (STFR) Meter which can quantitatively estimate the available nutrients in soil such as organic carbon, nitrate, phosphorus, potassium, sulphur, zinc and boron
3. The digital embedded system instrument according to claim 2 wherein, the said STFR meter can also recommend fertilizer dose crop and target yield, based on targeted yield model.
4. The digital embedded system instrument according to claim 2 wherein, the said STFR meter can run on a 9V dry cell as well as with a 9-12 V AC adapter.
5. The digital embedded system instrument according to claim 2 wherein, the said STFR is a low cost and user friendly instrument
6. A digital embedded system instrument substantially as herein described with reference to the drawings.