Many farmers ask whether they can mix urea, CAN and Compound D together and apply once as top dressing. On the surface it may look like a good idea — all fertilizers in one pass. But agronomically, this is not recommended.

Understanding each fertilizer

Urea (46% N)
Very high nitrogen fertilizer. It is mainly used for top dressing because crops need a lot of nitrogen during vegetative growth.

CAN – Calcium Ammonium Nitrate (about 26–28% N)
Also a nitrogen fertilizer, but safer than urea because it has lower risk of burning crops and less nitrogen loss.

Compound D (commonly 7-14-7 or similar)
This is a basal fertilizer. It contains nitrogen (N), phosphorus (P) and potassium (K). It is designed for application at planting to promote root development and early growth.

Why mixing them is a problem

1. Different purpose and timing
   Compound D is meant for planting time. Urea and CAN are meant for top dressing. Mixing them ignores proper nutrient timing.
2. Chemical incompatibility
   Urea does not mix well with ammonium nitrate products like CAN. The mixture absorbs moisture quickly and forms hard lumps.
   Urea also reacts with phosphate fertilizers (like those in Compound D), creating a sticky mass that reduces quality and uniform spreading.
3. Nitrogen loss
   When mixed together, especially if stored or exposed to moisture, nitrogen can be lost through volatilization (ammonia gas). This reduces fertilizer efficiency and wastes money.
4. Risk of crop burn
   Applying very high nitrogen concentration at once can damage roots, especially if fertilizer touches the stem. Young maize can suffer fertilizer burn.
5. Uneven nutrient distribution
   Because granules differ in size and weight, mixing can lead to separation during spreading. Some parts of the field may receive more nitrogen than others.

What should be done instead?

Correct maize fertilizer program (general example):

At planting
Apply Compound D as basal fertilizer (for example 200–300 kg per hectare depending on recommendation).

Top dressing
First top dress: 3–4 weeks after emergence using CAN or urea.
Second top dress: 6–7 weeks after emergence (if required), again using CAN or urea.

Important:
Use either CAN or urea. Do not mix them.
If using urea, apply before rain or lightly cover with soil to reduce nitrogen loss.

Conclusion

Mixing urea, CAN and Compound D together as top dressing is not agronomically correct.
Each fertilizer has its specific purpose and timing. For good yields and fertilizer efficiency:

• Compound D at planting
• CAN or urea as top dressing
• Apply separately and at the correct growth stage

Good fertilizer management increases yield, reduces waste, and protects your crop.