Healthy soil is dark, crumbly and full of life.
Why soil carbon decides your profit
On trial plots in Hyderabad, soil organic carbon rose from 0.35% to 0.85% in 15 months. Available nitrogen tripled and the soil became less alkaline. Nothing about this was magic: the farmers fed their soil carbon and life, season after season.
Soil organic carbon (SOC) is the single best sign of a living, productive field. When it is low, every bag of fertiliser works harder and returns less. When it climbs, the soil holds more water and nutrients, roots go deeper, and input bills fall.
This guide explains what SOC is, the steps that raise it, what we measured on XEN Farms trial plots, and how to track your own field.
What soil organic carbon is, and why most Indian fields are low
SOC is the carbon held in soil organic matter: decomposed roots, crop residue, manure and the microbes that live on them. It is what makes soil dark, crumbly and sweet-smelling.
Indian soil test reports usually grade organic carbon like this:
| Organic carbon | Rating | What it means in the field |
|---|---|---|
| Below 0.5% | Low | Hard, crusting soil; fertiliser response fades; water runs off |
| 0.5% to 0.75% | Medium | Workable, but needs regular organic inputs to hold the gain |
| Above 0.75% | High | Crumbly soil, better water holding, steadier yields |
Many fields in eastern and central India test below 0.5%. The usual reasons:
Heat: High temperatures burn organic matter quickly, so it must be replaced every season.
Residue burning and removal: Straw that could feed the soil goes up in smoke or off the farm.
Chemical-only nutrition: Urea and DAP feed the crop, not the soil biology that builds carbon.
Little manure going back: Cattle dung often goes to fuel cakes, or is spread raw and loses much of its value.
Six steps that raise soil carbon
Carbon builds when more organic matter goes into the soil than the soil burns off. These steps work on any farm size, and they add up.
- Stop burning residue. Chop straw and stubble and mix it into the soil, or leave it as mulch. Every tonne of residue is food for soil microbes.
- Return manure, but enrich it first. Raw dung releases nutrients slowly and unevenly. Well-made compost, FOM or vermicompost puts stable carbon back into the soil.
- Keep roots in the ground. A short cover crop or green manure (dhaincha, sunhemp, moong) between seasons feeds soil life when the field would otherwise lie bare.
- Feed the biology, not just the crop. Beneficial microbes turn residue and manure into lasting soil carbon. Biological inputs speed this up.
- Cut chemical overuse gradually. As soil carbon rises, the crop needs less urea and DAP. Reduce step by step, guided by soil tests, rather than all at once.
- Disturb the soil less. Fewer deep ploughings mean less carbon released into the air.
Where XEN Farms products fit
Carbovardhak Flow enriches the manure you already have. Mix 50 to 100 litres into each tonne of dung, FOM or vermicompost during composting. Enriched manure needs about one-third of the usual quantity per acre: roughly 1,000 kg instead of 3,000 kg.
Carbosutra is applied to the soil through drenching, flood or drip, at 15 litres per acre in 500 litres of water per application. It supplies carbon, nutrients and beneficial microbes together.
See doses for your crop on our products page.
What we measured on trial plots
Across two independent trials, soil organic carbon roughly doubled within 15 to 17 months of using XEN Farms inputs alongside good organic practice.
| Trial | Period | Organic carbon | Available nitrogen | Soil pH |
|---|---|---|---|---|
| Krishna Sudha Academy of Agri-Ecology, Hyderabad, with BAIF | 15 months | 0.35% to 0.85% | 180 to 560 mg/kg | 8.5 to 7.5 |
| Field soil, NABL-accredited lab report | Dec 2023 to Apr 2025 | 0.369% to 0.680% | 210 to 413 mg/kg | 8.35 to 7.76 |
Plot-by-plot results from the Krishna Sudha Academy and BAIF trial: pH, nitrogen and organic carbon, 2023 (blue) versus 2025 (orange).
Two things stand out. Both plots moved from the “low” carbon band toward “high”, and both became less alkaline, which frees up nutrients that high-pH soil locks away.
The gains keep building with time. Sandip Patidar, a farmer in Ranjangaon village near Pune, saw his soil organic carbon rise from 0.4% to 2.25% after 30 months of carbon farming.
Sandip Patidar's soil health report after 30 months: organic carbon 2.25%, rated "very high".
Results depend on your soil, crop, climate and how consistently the practices are followed. That is why testing your own field matters.
How to test your soil and track progress
A soil test before you start, and one every year after, shows whether your carbon is really rising.
- Take a proper sample. Collect soil from 8 to 10 spots across the field, 0 to 15 cm deep, in a zig-zag. Mix it well and keep about half a kilo.
- Use a reliable lab. Your local Krishi Vigyan Kendra (KVK), the Soil Health Card scheme or an NABL-accredited lab can test organic carbon, pH, nitrogen, phosphorus and potassium.
- Test at the same time each year. Sample in the same season, before sowing and before adding manure, so the numbers compare fairly.
- Keep a simple record. Note organic carbon, pH and NPK each year, along with your input costs and yield per acre.
XEN village-level entrepreneurs (VLEs) also help farmers with soil testing and follow-up in the areas we serve. Find out about the network.
Frequently asked questions
How fast can soil organic carbon increase?
It depends on the starting level, climate and practices. On our trial plots it roughly doubled in 15 to 17 months. Expect steady gains over several seasons rather than overnight change.Do I have to stop chemical fertiliser completely?
No. Reduce it step by step as your soil improves, using soil tests to guide you. Many farmers cut chemical use sharply once their soil carbon recovers.Is raw cow dung enough?
Raw dung helps, but it decomposes slowly and loses value in the open. Composting or enriching it first gives the soil more stable carbon from less material.Will my yield drop while I switch?
On XEN demonstration plots, farmers saw yield gains from the first season. Results vary by crop and soil, so start on part of your land and compare.
Start with your own field
Talk to us about a programme for your crop and soil, or about joining the XEN Rural Entrepreneur Network.
Call Diptesh Mukherjee: +91 72766 75543
Call Sayandeep Das: +91 86200 55135