Emission of NH3 and N2O after spreading of pig slurry by broadcasting or band spreading

The recommended method of reducing the emission of NH 3 while spreading manure is to plough or harrow the manure into the soil. This in turn increases the possibility of N 2 O emission. At two sites in southern Sweden emissions of NH 3 and N 2 O were measured after spreading pig slurry by broadcasting and band spreading. The band spreading technique can be used in growing crops i.e. when nitrogen is most needed, and it is thought that the NH 3 emission is smaller with this technique compared to broadcasting. The average NH 3 loss was 50% of applied NH 4 + during warm/dry conditions and 10% during cold/wet conditions. The N 2 O emission was always less than 1% of applied NH 4 + .When the NH 3 emission decreased, the direct N 2 O emission increased. However, when taking into account the indirect N 2 O emission due to deposition of NH 3 outside the field, the spreading techniques all produced similar total N 2 O emissions. The ammonia emission was not much lower for the band spreading technique compared to broadcasting, when compared on seven occasions.