In the region of 90 million tonnes of farm manures, supplying 450,000 tonnes of nitrogen (N) and 119,000 tonnes of phosphorus (P) are applied to agricultural land in the UK each year. These applications are a valuable source of plant nutrients but they are also recognised as the largest source of controllable pollution in present day farming systems. Over 70% of nitrate entering water systems is estimated to originate from agricultural land and the transfer of particulate and soluble P from agricultural land has been estimated to contribute 40-50% of P loads in watercourses. Ammonia (NH3) emissions from UK agriculture contribute c.80% of total UK emissions with losses following the land spreading of farm manures responsible for c.96,000 tonnes of NH3 each year.