Slurry timing & application to protect the environment
Good management of Slurry is needed to maximise grass growth, while at the same time minimise losses to our atmosphere and water bodies. ASSAP Advisor Ivan Kelly has some useful advice.
Slurry is fully of valuable nutrients but can damage our environment if not managed correctly. For example, Phosphorus within the slurry can be washed into waterbodies causing eutrophication or nitrogen can be lost through gaseous emissions.
Fortunately, there are some key practices that can reduce these losses. Spreading at the right time and using the best methods increase yield response and reduces the risk to the environment.
Firstly, Slurry should only be applied when soil temperatures are above 6 degrees and ground conditions and weather forecast are suitable. It is important that the applied slurry gets down to the roots of plants such as grass in the growing season, preferably bare fields or fields with low grass cover. On very heavy land it may be necessary to delay spreading until after the first cut silage. Extra slurry storage allows more flexibility on spreading times, particularly in a very wet spring.
Agriculture accounts for 98% of ammonia emissions in Ireland and land spreading of slurry accounts for almost half of this total. Spreading slurry with a trailing shoe, dribble bar or injector system can reduce the ammonia emissions, increase nitrogen value, reduce odours and grass contamination while allowing more flexibility regarding spreading time.
Many contractors are using the Umbilical (Pipe) system to pump the slurry from the yard to the tractor mounted unit. This system is particularly high risk to water quality if use incorrectly, as it allows slurry to be spread when a slurry tanker wouldn’t be able to travel on land due to ground conditions. While this system does reduce soil compaction, it should not be used on saturated soils as it would pose a risk to local water quality.
The GLAS scheme includes low-emission slurry spreading as an option while Low emission equipment is grant aided under TAMS.
Derogation Farmers, 6000 of Ireland’s most heavily stocked farms, must apply all slurry after the 15th April annually by Low Emission methods.
Slurry can be a valuable asset on a farm, but only if managed correctly. By minimising losses through careful application, farmers can retain more Nitrogen, reduce sward contamination and reduce the fertiliser bill on the farm. This will increase farm profit while helping to protect our air, atmosphere and water quality.