Teagasc is advising that fertiliser application on winter cereals will be the priority over the coming days.

There are large differentials in nitrogen (N) cost this season, depending on time of purchase and N type.

Many farmers will opt for urea, as the current 33% price differential with calcium ammonium nitrate (CAN) is difficult to ignore in a season of tight margins.

Where phosphorous (P) and potassium (K) are required, the first N application will be in a compound fertiliser.

Fertiliser application

Based on Teagasc costs and returns figures, if a winter wheat grower switched from CAN to urea for the N top dressing, this would represent a saving of over €7,000 for a 40ha grower.

The equivalent saving for a spring feed barley grower would be over €3,000 for 40ha.

Teagasc research has shown that there is no significant difference in grain yield whether a farmer uses protected urea or CAN. However, sulphur application needs to be planned and spreading at wide bout widths is more difficult.

Urea is less dense than CAN, typically 75-80% of standard fertiliser, which makes it more difficult to spread evenly at wide bout widths. Think of applying the same force to a table tennis ball and a golf ball.

Urea will also be more impacted by wind; therefore, good quality urea is essential when spreading at wide bout widths and it is essential that the fertiliser spreader is set up correctly for spreading urea.

Spreading urea

The settings for spreading urea will be different to those for spreading CAN, so consult the spreader manufacturer’s recommendations for the specific product being spread.

Once fertiliser calibration is complete, it is important to use trays or mats to check the spread pattern in the field.

The break-even ratio (BER) is the point on a graph called the economic optimum rate, where the additional yield will not cover the cost of the N applied.

The cost of N and the price of grain will dictate whether an adjustment to the optimum N rate is required or not.

Based on the BER, a grain price of €240/t for wheat and an N cost of €3.00/kg (CAN €810) would require a 39kg/ha reduction from the optimum rate.

However, very little adjustment is required when N is costing €2.00/kg (urea €920), where a 14kg/ha adjustment is required, according to Teagasc.

Making the most efficient use of applied N is crucial, so target application to match crop requirements and ensure soil conditions are good to avoid leaching losses.