Rule of Thumb:
| Soil Depth | Extra Water Storage from +1% SOC | In l extra water storage per hectare. | In m³ per Hectare |
|---|---|---|---|
| 10 cm | ~2 mm | 20,000 L | 20 m³ |
| 30 cm | ~6 mm | 60,000 L | 60 m³ |
| 100 cm | ~20 mm | 200,000 L | 200 m³ |
The idea of increasing soil organic carbon (SOC) by a full percentage point across 30 cm depth may sound ambitious, but in many contexts it is achievable within 10–20 years of regenerative management. What does +1% SOC mean in practice? A 30 cm soil layer with a bulk density of 1.3 g/cm³ weighs about 3,900 tonnes per hectare. Raising SOC by 1% requires adding ~39 tonnes of carbon per hectare, equivalent to ~70–80 tonnes of organic matter once moisture and mineral fractions are considered. Spread over a decade, this requires only 7–8 tonnes of stable organic matter addition per year which is achievable with cover crops, diverse rotations, compost, and grazing integration.
Regenerative practices accelerate this process by increasing carbon inputs (roots, residues, manure) while reducing losses (tillage, bare fallows). Deep-rooting perennials and cover crops especially help build SOC deeper into the profile, ensuring the gain is not confined to just the top 5–10 cm. Real-world evidence shows that +0.1–0.3% SOC gains per year are possible in degraded soils under regenerative practices. On a 10–15 year horizon, this translates to +1–3% SOC in the topsoil, which is consistent with global meta-analyses of soil carbon sequestration. So while +1% SOC in 30 cm depth is not an overnight outcome, it is a realistic, documented trajectory for regenerative agriculture. It represents a measurable, achievable improvement in both water storage and soil resilience.
https://www.youtube.com/watch?v=TmpsJOZBZOU
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