Improving nitrogen-use efficiency in wheat

With global fertiliser prices at a two-year high, nitrogen use came under the spotlight at the 2021 SKOG Pre-Plant Information Day. Speaking at the event, agronomist Jacques Smith highlighted the importance of a holistic approach to nitrogen fertiliser management in grain crops.

- Jeandre van der Walt

FAST FACTS

Nitrogen influences each stage of the plant’s life cycle.

About 80% of a wheat plant’s protein comes from nitrogen mobilised from the leaves.

Jacques Smith advises wheat farmers to apply between 60% and 70% of the plants’ nitrogen requirements during the leaf emergence stage.

Nitrogen (N), in conjunction with the climate, is one of the most important determinants of grain yield. However, due to the relatively high cost of N fertiliser, especially in dryland production, farmers need to apply it as effectively as possible to ensure profitability.

This was the key message of Jacques Smith, an agronomist at agricultural product company Yara, who spoke at the recent annual SKOG Pre-Plant Information Day presented virtually and hosted by the Western Cape Department of Agriculture.

According to Smith, economical N fertiliser rates vary considerably across grain production regions due to the complexity of the soil N cycle. These rates also differ from year to year, from farm to farm, and even from one field to another on the same farm.

NITROGEN-USE EFFICIENCY

The variation in N levels is linked to the concept of nitrogen-use efficiency (NUE).

“To include all the NUE factors and ensure that profits are optimised, it’s important to approach nitrogen fertilisation more holistically,” explains Smith.

NUE concerns the relationship between total N input and N output.