As the slurry season comes to an end, Northern Ireland (NI) Water is reminding farmers to protect watercourses when spreading slurry or manures over the next week.

The utility said that the timing and placement of slurry, manure and fertiliser should be carefully considered so that there is no risk of water pollution.

It added that steep slopes and soils with impeded drainage are vulnerable to runoff and losses during rainfall events.

"A rainfall event lasting only a few hours can distribute a large proportion of the total annual loading of phosphorus to rivers and lakes," NI Water said.

The closed period prohibits organic manures, including slurry, poultry litter, sewage sludge and abattoir waste, from being spread from October 15 to January 31.

While farmyard manure cannot be applied from midnight October 31 to January 31.

NI Water has advised farmers that over the next week organic manures, including dirty water, must not be applied:

Within 250m of a borehole used for public water supply;
Within 50m of a borehole, spring or well;
Within 30m of lakes;
Within 15m of a waterway other than lakes (reduced to 5m when using LESS);
On waterlogged soils, flooded land or land likely to flood;
On frozen ground or snow-covered ground;
If heavy rain is forecast in the next 48 hours;
On steep slopes with an average incline of 20% or more on grassland, 15% or more on all other land.

Roy Taylor, NI Water catchment manager, said that “care in timing and placement of slurry, manure and fertiliser is vital to minimise the potential for loss from land to water".

"If slurry is spread on poor, very wet ground or during or just before wet weather conditions, it can run off the land; this results in valuable nutrients ending up in our watercourses.

"Abstracting this from our water is difficult and expensive to treat, however NI Water must do this in order to provide the high-quality drinking water we all expect," he said.

NI Water has also published suggestions on how farmers can improve water quality:

Only spread slurry and fertilisers when conditions are suitable;
Use the Department of Agriculture, Environment and Rural Affairs (DAERA) online tools to calculate your farm’s phosphorus (P) balance and manure nitrogen (N) loading;
Check your farmyard for slurry run off and sources of pollution;
Prevent cattle access to rivers causing erosion, sediment loss and pollution;
Nutrient management planning – if available use your Soil Nutrient Health Scheme results and run off risk maps;
Minimise Phosphorus inputs – meet P crop requirements from manures. Each tonne of concentrate feed contains approximately 5kg of P;
Eliminate chemical P fertiliser;
Follow the Nutrients Action Programme to farm efficiently.