SLURRY SPREADING AT HILLSBOROUGH - RECENT RESULTS
Peter Frost
Current research at the Agricultural Research Institute of Northern Ireland is examining the trailing-shoe system for spreading slurry. Results to date have shown that the system not only increases grass yield but also increases the efficiency with which the nitrogen in slurry is used.

Slurry is a valuable, though under used, source of fertiliser. In Northern Ireland, slurry is usually applied to grass by a slurry tanker fitted with a splash plate. This method of spreading can lead to loss of valuable nitrogen fertiliser from the slurry through ammonia emissions into the air.

Research at the Agricultural Research Institute of Northern Ireland is assessing a trailing-shoe slurry spreader as a method for lowering nitrogen losses from slurry.

This trailing-shoe machine places the slurry directly onto the soil surface and has potential to both lower ammonia emissions and increase the value of the slurry as a fertiliser. Applications of slurry by this method may also give further benefits through less odour, reducing contamination of the grass and consequently, reducing the possibility of negative effects on silage quality and utilisation by grazing animals.

Hillsborough results to-date show that compared with splash plate spreading, the trailing-shoe system increased the nitrogen fertiliser value of the slurry by 50% and increased grass yield by 12%. Observations at the time of harvest indicate less contamination of herbage when slurry is spread by trailing shoe rather than by splash plate. However, the costs of buying and operating the trailing-shoe machine together with its practicality have to be set against these gains. This area of work continues at Hillsborough.