What is my nitrogen loading?

Implementation of the Nitrates Directive requires a number of measures to reduce or prevent nutrients from agriculture entering our waterways. One such measure will limit the amount of manures that can be applied. For any farm the amount of total nitrogen (N) in organic manures applied to the land, including by the animals themselves, and that brought onto the farm, shall not exceed 170 kg N/ha/year.

Standard values for the amount of total N in the manure of each stock type are used to calculate this loading. The total N contributions are added up for all stock types and then expressed over the area farmed. An example below shows how the N loading is calculated for a 66 ha farm with 100 dairy cows and followers.

	Stock Numbers	N loading per stock	Total N Loading
Dairy Cows	100	91	9100 kg
Cattle 1 year - 2 years	30	47	1410 kg
Calves 6 months - 1 year	30	12	360 kg
Calves 0 to 6 months	30	7	210 kg
			11080 kg
		Adjust for imported (+) or exported (-) manure	0 kg
			N loading is 11080 kg/66 ha = 168 kg N/ha

Limiting the application of manure N effectively introduces a maximum farm stocking rate. The various enterprises are affected differently. Poultry, pig, and dairy farms show higher loadings per hectare compared to beef and sheep farms due to the high N content of the manures produced and the more intensive nature of these enterprises. However in Northern Ireland, it is estimated that approximately 90 percent of farms are currently operating below the 170kg N/ha/year limit and will therefore not be restricted by the proposed limit.

Enterprise Type	Approximate land requirement to comply with 170 kg/N limit only
1000 Broiler breeders	4.5 ha
1000 Laying hens	3.6 ha
1000 Broilers (6.6 crops / yr)	1.5 ha
1 sow ( birth to bacon unit)	0.5 ha
1 Dairy cow ( plus followers )	0.66 ha
1 Suckler cow ( plus calf )	0.36 ha
1 Breeding ewe ( plus lamb )	0.06 ha

Almost all poultry units and the majority of pig units currently operate above the proposed 170kg N/ha/year limit. On a dairy farm a loading of 170 kg N/ha/year equates approximately to the average stocking rate found on Northern Ireland dairy farms of 2.0 LU/ha. Therefore approximately 50 percent of dairy farmers are currently operating within the proposed N limit. Almost all beef and sheep farms are significantly below the proposed N limit.

The proposed Action Programme also includes phosphorus (P) controls. It is anticipated that complying with these P controls will require additional land to that required for manure N on the intensive enterprises.

Short courses will be available later this year from the College of Agriculture, Food & Rural Enterprise (CAFRE) Telephone 028 9442 6898 to assist farmers in calculating their loading. Farmers can use the N loading calculator on this website under eservices. First time users need to register on the website to gain access to this programme.

The full Nitrates Directive Consultation Paper on the proposed Action Programme measures is available from www.doeni.gov.uk/epd, www.dardni.gov.uk or the Department of Environment (DOE) 028 9025 7365 . If you wish to comment on the proposals the closing date for comments is the 16 May 2005.