Dicyandiamide as a Nitrification Inhibitor
Nitrogen is the nutrient that most often limits crop yield, but a large share of the nitrogen applied as fertiliser can be lost before the crop uses it – leached as nitrate, volatilised as ammonia, or lost as nitrous oxide. Dicyandiamide (DCD; CAS 461-58-5) is one of the best-known nitrification inhibitors, used to slow the conversion of ammonium nitrogen to nitrate and so keep more nitrogen in the root zone.
This article looks at the fertiliser and nitrogen-management use of dicyandiamide. For the chemistry and specifications, see our overview of dicyandiamide: properties, manufacturing and applications.
What Nitrification Inhibition Means
In the soil, ammonium (NH4+) nitrogen is gradually oxidised by soil bacteria to nitrate (NO3–) – a process called nitrification. Nitrate is very mobile: it is easily leached by rain and irrigation and can also be lost as nitrous oxide. Ammonium, by contrast, is held by the soil and stays where the crop can use it.
A nitrification inhibitor slows the bacteria that carry out this conversion. Dicyandiamide does exactly this, which:
- reduces nitrate leaching – more nitrogen stays in the root zone;
- reduces nitrous oxide emissions – less nitrogen is lost as a greenhouse gas;
- improves nitrogen-use efficiency – more of the applied nitrogen reaches the crop;
- can improve yield where nitrogen loss is significant.
How Dicyandiamide Compares with Other Inhibitors
| Inhibitor | Type | Notes |
|---|---|---|
| Dicyandiamide (DCD) | Nitrification inhibitor | Established, cost-effective; used in fertilisers and blends |
| Other synthetic inhibitors | Nitrification inhibitors | Different persistence and application profiles |
| Urease inhibitors | Different mechanism | Slow urea hydrolysis, reducing ammonia loss |
Dicyandiamide is typically used in combination with a nitrogen fertiliser (or as part of a stabilised-fertiliser product), so that the inhibitor is applied at the same time as the nitrogen it protects.
Where It Is Used
| Application | Purpose |
|---|---|
| Stabilised nitrogen fertilisers | Slow nitrification so more N stays available to the crop |
| Pasture and grassland | Reduce nitrate leaching and N losses |
| Arable crops | Improve nitrogen-use efficiency |
| Environmental nitrogen management | Reduce nitrate leaching and nitrous oxide emissions |
Practical Points
| Point | Consideration |
|---|---|
| Rate | Set as a small percentage of the nitrogen applied; guidelines vary by crop and region |
| Placement | Applied with the fertiliser so the inhibitor is present where nitrification occurs |
| Persistence | Nitrification inhibitors are degraded over time in the soil; effectiveness is time-limited |
| Regulation | Use of fertiliser additives is governed by local agricultural rules |
Dicyandiamide Is Not Itself a Fertiliser
It is important not to confuse the two roles. Dicyandiamide is a nitrogen-management additive, not a nitrogen fertiliser in the ordinary sense: its value is in protecting and stabilising the nitrogen that a fertiliser supplies, rather than in supplying bulk nitrogen itself. That is why it is formulated into stabilised fertilisers rather than applied alone.
Frequently Asked Questions
What is dicyandiamide used for in agriculture?
As a nitrification inhibitor in stabilised nitrogen fertilisers, to slow the conversion of ammonium to nitrate and reduce nitrogen losses through leaching and nitrous oxide emissions.
Is dicyandiamide a fertiliser?
No, not in the ordinary sense. It is a nitrogen-management additive that stabilises the nitrogen supplied by a fertiliser; it is not a primary source of nitrogen.
How does an nitrification inhibitor help the environment?
By keeping nitrogen in the ammonium form for longer, it reduces nitrate leaching into water and cuts nitrous oxide emissions – both important environmental benefits.
How is dicyandiamide applied?
Normally as part of a stabilised fertiliser or a blend, so that it is applied with the nitrogen it is protecting; the rate is a small percentage of the nitrogen applied.
How do I buy dicyandiamide?
PolyBlueChem supplies dicyandiamide (CAS 461-58-5) at 99% min with a full Certificate of Analysis. Contact our team for specifications and a quotation.