Nitrogen is a powerful growth promoter in plants and one of the simplest, most cost-effective ways to grow more feed on your block. When used correctly, it boosts leaf growth and helps produce green, lush pasture. But it must be applied strategically to avoid waste, runoff, and environmental harm.

What Does Nitrogen Do?

• Promotes rapid leaf growth

• Gives plants a lush green appearance

• Helps increase feed yield quickly

• Deficient plants appear pale, stunted, and may turn yellow

Which Fertilisers Contain Nitrogen?

Several commonly used fertilisers supply nitrogen, each with slightly different properties:

Urea (46-0-0-0)

• Highly soluble

• Contains only nitrogen

Ammonium Sulphate (21-0-0-24)

• Soluble

• Supplies both nitrogen and sulphur

DAP – Di-ammonium Phosphate (18-20-0-2)

• Soluble compound fertiliser

• Contains nitrogen, phosphorus, and sulphur

MAP – Mono-ammonium Phosphate (11-22-0-1)

• Soluble compound fertiliser

• Also supplies nitrogen, phosphorus, and sulphur

Note: Fertiliser composition is always listed in the order of N-P-K-S-Mg.

When Should You Apply Nitrogen?

Apply nitrogen fertiliser strategically—that is, when you are most likely to see a strong response and economic return. Timing and soil conditions are crucial.

• Spring and early summer: Best response (80–100%)

• Late winter and early spring: Good response (60–80%)

• Autumn: Variable response, 20–40% in dry conditions or 50–70% after good rainfall

• Soil temperature: Must be above 6°C

• Soil moisture: Needs to be adequate for plant uptake

Application Rates

Keep in mind what clover contributes naturally to your nitrogen supply. A good clover crop may provide up to 200 kg N/ha per year.

Be aware of local environmental regulations. Some Regional Councils recommend a maximum of 150 kg N/ha per year from all sources combined.

Recommended rates:

• Grazed pasture: 20–40 kg N/ha (45–90 kg Urea/ha)

• Silage or hay: 30–60 kg N/ha (65–130 kg Urea/ha)

Exceeding these rates increases the risk of nitrogen leaching, especially in wet conditions.

Management Tips

• Apply nitrogen when some pasture regrowth is already present (about 1600–1800 kg DM/ha or 50 mm in height)

• Graze 4 to 5 weeks after application if conditions are favourable

• Cut for silage or hay 5 to 6 weeks after application

• Use nitrogen ahead of a predicted feed deficit, not during one

• Check your fertiliser spreader is delivering accurate rates

• Avoid spreading near waterways or drains

Used wisely, nitrogen can be a valuable tool to boost pasture growth. But overuse is wasteful, costly, and potentially harmful to the environment. Think ahead, match rates to conditions, and always consider what you’re already getting for free from healthy clover.

For an in-depth look at improving your soil, get our Soil & Fertiliser ebook.