Standardization of OC kit
Introduction
Soil organic carbon is a measureable component of soil organic matter. Organic matter makes up just 2–10% of most soil’s mass and has an important role in the physical, chemical and biological function of agricultural soils. Soil organic carbon improves soil structure.
The water holding capacity and rainfall infiltration properties of organic carbon soils creates better landscape moisture availability. Root development and rainfall variation tolerance is also significantly enhanced in soils with improved aggregation from carbon.
The determination of soil organic carbon is based on the Walkley-Black method. but it is expensive and time consuming and requires more chemicals and lab materials. and it is not feasible to farmers to check it.
To over come this problem Qualitative organic carbon detection kit is developed at BARC(Bhaba Atomic Research Centre) and modified (quantitative) in Vigyan Ashram. but there is no any standard comparison chart available, so to set this chart we are working on it. requirement , chemicals , procedure are known before. This is requirement of Cleanergy Tech Solutions Pvt. Ltd.
Procedure
To find the organic carbon mostly Walkley black method is used which is standard. so we are comparing every organic carbon percent with Walkley black method and our OC kit.
Firstly we need one sample which having high and known OC which is between 2-4 so we can make dilution of it and get other values.
So I took Agri-compost and find OC of it by Walkley black method which is 19.6%.
To dilute it we want one sample with zero OC, so I took cement and estimated OC by Walkley black method which is 0.00% .
Then I made dilution by using Agri compost and cement and estimated OC by WB method . Dilutions are as follows
- 40gm cement and 10gm compost – OC -: >4
- 50gm cement and 10gm compost – OC -: >4
- 70gm cement and 10gm compost – OC -: >4
- 90gm cement and 10gm compost – OC -: 2.3
In 4th dilution we get OC of 2.3 so we preferred fourth dilution and again diluted it to find out OC of sample which having less OC % , for that we used dilution as follows,
- 56gm cement and 44gm compost.( we get OC by WB is 1.6)
- 72gm cement and 28gm compost.( we get OC by WB is 0.93)
After getting these OC, I tested with OC kit after observation we did not get any colour change because we use cement to make dilutions. cement interfere in reaction so we don’t get any colour.
To over come this problem then we decide to use soil as diluting medium having low OC so we can get OC in the range 2-4%. So we made dilution as follows
100gm soil having 0.6 % OC and 10gm compost having 19.5% . after estimation of OC by WB it comes 1.95%.
After that we decided not to use any dilution medium further, we just use Sample A with different weight like 0.0,0.1,0.2,….. 1.0 and estimated OC with Walkley black as well as with OC kit and we get good results with both the methods and compare both.
We got color code for 3% OC and looking for 4% OC.
I had prepared 3 OC kit with comparison for further use. One is transfered to Cleanergy Tech Solutions Pvt. Ltd, One is transfered to Narmadalaya and one is in Vigyan Ashram (soil lab).
Preparation of Kit
- Solution A-
- Take 500 ml of distilled water.
- Add 10 gm NaOH pellet.and stir it manually up to dissolve .require 1-2 min.
- Fill in plastic bottle A
- Solution B-
- Take 500 ml of distilled water.
- Add 18.6 gm EDTA-Na salt,stir it.
- Add 5 gm of Di-sodium hydrogen orthophosphate.
- Add 22.5 gm of sodium pyrophosphate and stir up to dissolve by using a magnetic stirrer .It takes up to 5-7 min to dissolve.
- Fill in Plastic bottle B.
Requirement for 1 OC kit:- (Material and Quantity)
| Material | Quantity |
| Plastic bottle 500 ml capacity | 02 No. |
| Test tube with cap 30 ml capacity | 10 No. |
| Funnel 1” | 01 No. |
| Test tube stand *12 hard tube containing | 01 No. |
| Gloves | 02 pairs |
| Measuring cylinder | 01 No. |
| Spatula 1 gm capacity | 01 No. |
| Qualitative Filter paper | 50 No. |
| Hard Test tube 30 ml capacity | 02 No. |
Costing of 1 OC kit
| Material | Price in rupee (₹) |
| NaOH(10 gm) | 19.23+3.84=23.07 *Additional cost to prepare compare chart |
| EDTA(20 gm) | 53.2+10.64=63.84 *Additional cost to prepare compare chart |
| Disodium hydrogen orthophosphate (5 gm) | 7.0+1.4=8.4 *Additional cost to prepare compare chart |
| Sodium pyrophosphate(22.5 gm) | 34.5+6.9=41.4 *Additional cost to prepare compare chart |
| Test tube with cap(10 units) | 900.0 * can be reduced |
| Plastic Bottles(2 unites) | 120.0 |
| Funnel(1 unit) | 28.0 |
| Filter paper(50 units) | 560.0 * can be reduced |
| Test tube stand (1unit) | 168.0 |
| Cloves(2pair) | 24.0 |
| Test tube (2 units) | 100 |
| Spatula(1 unit) | 20.0 |
| Distilled Water(1200 ml) | 24.0 |
| Container bag (1 unit) | 400.0 * can be reduced |
| Total | 2480.7+18%(Tax)= 2927.22 |
The Cost of 1 OC kit is 2927.22 with all taxes.
The cost of test tube with cap, filter paper and container bag are quite high they can be reduced.
The cost of test tube with cap is reduced by preparing comparison color chart on paper which matches same as our comparison tubes so we can reduce it from 900 to Max 60-100.we can reduce cost up to 800+ rupees.
The cost of filter paper are reduced by using low cost filter paper which filter soil from mixture ,and it can be reduced from 560 to 100,here we can reduce up to 450+ rupees.
The cost of OC kit container bag is reduced by using low cost and high efficiency bag which can be retained up to at least 1-2 years. and it can be reduced from 400 to 250-300, we can reduce up to 100-150 rupees.
Totally we can reduce up to 1300 to 1350 rupees
2480-1350=1130
by adding taxes it can be , 1130+18% (Tax)=1333.4 ₹
OC kit Material and Dimensions
| Material | Dimensions (in cm) |
| 1) Test tube stand +tubes | 23×16×7 |
| 2) 2 Plastic Bottles | Height-17,radius-4 |
| 3) funnel | Height-15,Diameter-8.5 |
| 4) filter paper box | 15×15×2.5 |
| 5)Measuring cylinder | 13×2.5 |
| 6) Spatula | 4×1 |
| 7) Gloves | 18 x 11 (it can be fold) |
How to use OC kit video
