Nitrogen rates for spring barley
The aim of this project is to increase the competences of spring barley growers in selecting appropriate N rates and timings. N will be used more efficiently, producing better yields and gross margins, with less N being lost to the environment
After late sowing, inadequate nitrogen (N) fertilization has been identified as the second most important husbandry factor responsible for low spring barley yields, where low N (i.e. 40 KG/ha instead of 80 KG/ha) can reduced grain yield by 1.5t/ha.
Last September a benchmarking exercise was carried out with selected growers in which grain yield and percentage grain N was related to soil type, field history, application of organic manures and crop management.
The table below summarises how grain N analysis can help you to evaluate your N application decisions for future crops.
Interpretation of Spring Barley Grain N
- Grain N less than 2.0 percent
Grain N is low. Applying more N may have resulted in a higher yield (assuming nothing else was limiting the crop’s ability to use N). - Grain N between 2.0 and 2.1 percent
Grain N is close to optimum. You applied close to the optimum rate of N. - Grain N greater than 2.1 percent
Grain N is high. The crop may have produced a similar yield at a lower N input. You may have applied too much N, raising your variable costs unnecessarily and increasing the risk of nitrate leaching. You may have applied N too late. If yield was low, this is unlikely to have been because of insufficient N.
Progress to Date
Samples from last year have indicated that up to 64 percent of growers applied N levels that were below the optimum.
Farmers who are interested in having their grain sampled for percentageN should contact Malachy Mason at Greenmount Campus.