Tillage management: Keep an eye on nitrogen rates on spring cereals

Fertiliser spreaders were busy travelling all roads of the country before rain hit this week. As spring crops receive nitrogen (N) remember your limits.

Spring barley

Crops grown on soils in index 1 may receive 135kg N/ha.

Those in index 2 can receive 100kg N/ha, while crops on index 3 and 4 for nitrogen can have 75kg N/ha and 40kg N/ha applied respectively.

Farmers who can prove yields higher than 6.5t/ha at 20% moisture content in any of the past three harvests may apply an additional 20kg N/ha for each 1t/ha above this yield.

Spring malting barley

Farmers who struggle with low protein and who have a malting barley contract may apply an extra 20kg N/ha where agronomic advice suggests that this will address the issue.

However, in recent years achieving low protein contents has been a challenge for a large number of growers.

Trials from Teagasc have shown that an application rate of 120kg N/ha is an ideal rate that can maximise the chances of producing low protein malting barley.

Also Read: Meeting malting protein specs more valuable than ever…here are some tips

Richie Hackett (Teagasc) has also described how protein content reduces by 0.2% per 10kg N/ha reduction in nitrogen rate. Therefore, it is important to look at previous protein results and gauge the nitrogen rate accordingly.

However, achieving the optimum protein content is easier said than done.

Data source: DAFM

Spring wheat

Spring wheat crops grown on soils in index 1 can receive up to 160kg N/ha. This amount decreases to 130kg N/ha on index 2 soils and to 95kg N/ha and 60kg N/ha on index 3 and 4 soils respectively.

Where proof of yields above 7.5t/ha at 20% moisture content in the past three years are available, an extra 20kg N/ha can be applied for every additional 1t/ha above this yield.

Spring oats

Nitrogen limits for spring oats are much lower. Crops planted in index 1 soils can receive 110kg N/ha.

On index 2 soils spring oat crops may have 90kg N/ha applied, while 60kg N/ha can be applied to crops on index 3 soils and 30kg N/ha is the limit on index 4 soils.

The opportunity to apply 20kg N/ha for additional yield occurs once proof of yield above 6.5t/ha (at 20% moisture content) can be proven in the past three years.

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