Do cover crops supply enough nitrogen?

We have had a warm, dry spell after a wet winter. Most crops will have gone into good seedbeds so it is best to make the most of this. Rapidly establishing these spring cereals is key to achieving a large leaf area to capture optimum light levels in the coming months. 

Phosphate is particularly important for the young plants as it is a key factor in rooting, especially with the potential lack of water as it grows through the dry topsoil. Therefore an adequate supply of phosphate during this period of rooting is essential as well as early nitrogen applications to improve uptake efficiency.

There is generally little evidence to show a yield benefit from splitting nitrogen applications for spring cereals compared to putting it all in the seedbed. However where cover crops have been grown prior to drilling, saving a proportion until later in the season may allow for adjustments to be made according to the release of nitrogen that occurs. 

Although the use of cover crops in a rotation can help with nutrient cycling (capturing nitrogen over winter that may otherwise be lost through leaching), they are unlikely to supply all the nitrogen back in time for the following crop to utilise it. Therefore, in these situations, tissue samples during the season can help to identify the levels of nitrogen in the crop to identify the need for additional nitrogen. 

For more information on spring cereal nutrition