Nitrogen: The closed period for spreading slurry and chemical fertiliser has ended for farmers in Zone A. Farmers in Zone B can spread from Saturday and farmers in Zone C and in Northern Ireland can spread from 1 February. The policy around early nitrogen on light soils is shifting, as the focus is moving more and more towards nutrient use efficiency. The first step in this is to use early slurry to replace early nitrogen. Every 1,000 gallons/ac of slurry spread with low emission applicators is worth around nine units of nitrogen/ac, so 2,500 gallons/ac equals 23 units/ac. The response is lower when slurry is spread with a splash plate.
The best response to early chemical nitrogen will be when soil temperatures are above 6°C, ground conditions are good and grass varieties are mostly perennial ryegrass. If these conditions present themselves in January, then that means it is safe to spread, but if it means waiting until February then so be it. A maximum of 20 to 25 units/ac is advised. Urea is the nitrogen of choice in early spring. From an ammonia emissions perspective, the risk of losses in early spring is low, but unless protected urea is used, ammonia losses from using ordinary urea will be added to the national inventory.