25 February 1999
Nitrogen on winter barley


HOW much nitrogen should I be applying to my winter barley now when it hasnt had any at all since sowing?


David Millar, Crops magazine


BARLEY crops are looking yellow at the moment in Scotland. This is mainly because of waterlogging and manganese deficiency, although lack of nitrogen is also having an effect.

Crops suffering from manganese deficiency can also suffer from very cold weather, so growers should wait for better weather before treating with manganese. Beware frosty conditions, which will cause severe scorch.

If the yellowing is due to nitrogen deficiency, there are two arguments.

One says put on a small interim application (up to 40kg/ha) because stressed crops lack good root structure and nitrogen will have leached out of the root zone.

The other argument is for holding off until a main top dressing because an application now will have little effect and crops are generally well capable of recovering even when nitrogen is held back until mid-March.

Much depends on local conditions, particularly with regard to waterlogging and leaching, and to how sensitive the grower is to neighbourly jibes about sick crops.