here details discuss about organic carbon in soil

1. Rashtrapita Mahatma Gandhi Art’s and Science College, Nagbhid
Dist.- Chandrapur
Online Webinar
Topic- Determination of Organic Carbon from Soil
Resource Person
Dr. Ganesh D Satpute
Head Dept. of Chemistry
Shri. Govindrao Munghate College, Kurkheda
Dist- Gadchiroli

2. Introduction-
• TOC
______________
Inorganic carbon Organic carbon
•organic carbon vital component of agricultural soil
•It supplying nutrients, improves soil structure, facilitate water infiltration
and retention.
• Soil organic matter is also the source of nitrogen in soil and hence its
determination also acts as an index of nitrogen availability.
•It is vital role in fertility of soil.

3. Methods and Materials-
Walkley and Black Rapid Method
(Titration Method )
Reagent- 1. 1 N Potassium dichromate (K2Cr2O7 )
2. 0.5 N Ferrous Ammonium Sulphate (NH4)2 Fe (SO4)2·6 H2O)
3. Sodium Fluoride (NaF)
4. Diphenylamine Indicator

4. Procedures:-
1. 1 gm soil weighed was taken into 500ml conical flask .
2. 10 ml of 1N K2Cr2O7 added into conical flask.
3. Then 20 ml of concentrated H2SO4 into conical flask.
4. The flask was kept on asbestos sheet for 30 minutes. Thereafter
200 ml distilled water was added slowly into the flask.
5. Add one spatula sodium fluoride
6. Then added with 1 ml of diphenylamine indicator
7. Samples were then titrated with 0.5N ferrous ammonium sulphate
solutions until green colour appeared.

5. Calculation :-
Organic Carbon (%) in soil = (B - T) × × 0.003 × × F (1.33)
Where:
B- Ml of standard FeSO4 required for blank.
T- Ml of standard FeSO4 required for sample.
F- Walkely found an average recovery of 77 %
i.e. - A correlation factor of
= 1.33
Percentage of organic matter = % of organic carbon × 1.72.