1. Proposal for Derogation, under Paragraph 2(b) of Annex III of Nitrates Directive, from the limit of 170 kg N/ha/year from livestock manure for grassland farming in Northern Ireland
Response to Questions
From Member States
29 June 2007

2. Germany
Question 1 Minimum storage capacity and exceptions from the basic rule.
Response:
Minimum storage requirements are as follows:
- 26 weeks for pig and poultry
- 22 weeks for others
The calculation of storage requirements however, can take account of specific farming practices.

3. Germany
Question 2 Conditions of fertiliser application near water courses
Response:
The Action Programme establishes the manner and method
of nitrogen fertiliser application including the minimum distances
from waters.
eg. 20 m from lakes
10 m from any waterway
(other restrictions detailed in Regulations)

4. Germany
Question 3 Limitations of fertiliser application to ensure a balance between N requirement of the crops and N supply
Response:
The Action Programme limits the total nitrogen in livestock manure to 170 kg N/ha/year and limits the amount of chemical fertiliser and organic manures that may be applied to crop requirement.

5. Germany
Question 4 By which method will the amount of N applied livestock manure be identified – legally binding values?
Response:
The Action Programme sets legally binding values of manure N
excretion for each livestock type.

6. Germany
Question 5 Methods of spreading liquid manure? Any obligation on derogated farms to use specific emission reducing methods?
Response:
The Regulations introduce an obligation on all farms to use emission reducing methods to spread slurry.

7. Germany
Question 6 How will compliance with the measures of the Action Programme be controlled?
Response:
Regular monitoring and enforcement will be carried out by the
Environment and Heritage Service of the Department of the
Environment.
Farms will be inspected on a risk - based assessment to ensure
compliance with the Nitrates Action Programme.

8. Finland
Comment 1 Justification of derogation on basis of denitrification capacity conflicts with serious debate on climate change.
Response:
Denitrification is highlighted by Nitrates Directive as grounds for derogation.
Majority of Northern Ireland soils have impeded drainage.
Denitrification loss significantly lowers soil nitrate concentration and hence lowers nitrate loss to water.
Northern Ireland is not complacent about impact of denitrification
and a major research programme is in place to address this issue

9. Finland
Comment 2 Yield statistics do not necessarily give the correct picture on N uptake potential, especially in areas of poor growth
Response:
Over 71% of Northern Ireland is classified as above average grass growth.
Grass growth classification is based on detailed knowledge of soil type and long term (30+ years) rainfall etc.
With the exception of 2002, average yields of ryegrass swards on farm have exceeded 10 t DM per ha, with average yields of new varieties from 1990 to 2006 averaging 12.7t DM/ha.
Majority of farms seeking a derogation are grassland farms located
on better quality land and better grass growing areas.

10. Monitoring – Predicted Distribution of Derogated Farms
Map shows distribution of farms that are predicted to apply for derogation.
Farms widely distributed throughout Northern Ireland.
Distribution primarily reflects land quality.
Most are located on better quality land
-Land classes 1 and 2.
Predicted farms account for 2.8% of farms and 4.3% of farmed area of Northern Ireland

12. Finland
Question 1 Check values in Table 4.5 (page 38). Does this increase the N balance for Farm C (derogated farm)?
Response:
We apologise for the typographical error in Table 4.5.
Correct data are now included – N balance data are changed, but P balance data are not affected.
Derogated farms with a high reliance on grass can achieve a lower N balance and a significantly lower P balance than non derogated farms.
Introduction of P balance of 10 kg/ha on derogated farms will constrain concentrate (and hence N and P) input

13. Worked example of calculation of surplus N and P on non-derogated and derogated farms (1)
Farm type A
Non-Derogated B
Non-Derogated C
Derogated
Livestock manure N (kg/ha)
170
170
250
Concentrate use
(tonnes/cow)
1.5
2.5
Milk yield
(kg/cow)
6360
7630
Milk output
(kg/ha)
17,500
14,200
11,800

14. Worked example of calculation of surplus N and P on non-derogated and derogated farms (2)
Farm type A
Non-Derogated B C
Derogated
N inputs (kg/ha)
Chemical fertiliser or other organic manures
272
Concentrate 80
134
119
Atmospheric deposition and fixation 10
Total N input
362
416
401
Total N off-take (kg/ha) 66 79 99
Surplus N
296
337
302
Surplus P (kg/ha)
2.5
10.5
3.1

15. Italy
Question 1 Have other options been evaluated to maintain farmers’ income e.g. reduction in grassland and increase in cereals?
Response:
Limitation in stocking rate arising from 170 kg manure N/ha will reduce livestock output and income/ha.
Livestock production in N Ireland is grass-based – only 4.5% of farm area is in arable crop production.
Energy and protein yield from arable crops is much lower than from grassland and high rainfall creates harvesting difficulties.
Livestock farmers in Northern Ireland have limited opportunity to grow arable crops to replace grass and are more likely to increase purchase of imported feeds – increasing N and P input onto farm

16. Higher Manure N Application Facilitates Grass- Based Systems
Concentrates Milk Yield Herbage Required
(t per cow) (kg per cow) (t DM per ha)
170
(17472 kg
milk/ha)
250
13.2
12.4
11.7
10.9
10.2
(kg manure N/ha)
(17803 kg
milk/ha)

17. Italy
Question 2 Have increases in N efficiency from animal manures through dilution or manure separation been considered?
Response:
Much research effort in N Ireland has focussed on improving efficiency of N use from animal manures.
Recommended strategies include separation, dilution, washing, acidification and spreading method– e.g. efficiency of ammonium N increased from 0.37 to 0.64 by trailing shoe application.
New spreading methods have been widely advocated by research and
advisory organisations

18. Separated liquid fraction (screen size)
Efficiency of ammonium N in slurry relative to herbage yields obtained with inorganic nitrogen fertilizer (from Frost et al., 1990, Stevens et al., 1992 and Frost et al., 2007)
Method of application
Splashplate
Trailing shoe
Separated liquid fraction (screen size)
1:1 water dilution
5mm
3mm
.25mm
0.37
0.64
0.56
0.73
0.76

19. Demonstration of Trailing Shoe System

20. The Netherlands
Question 1 In the system in Northern Ireland are soil P analyses mandatory and how does this influence use of P fertilisers?
Response:
Yes, soil P tests are required for the use of chemical fertilisers containing P.
All chemical P fertilisers are assumed to have 100% availability.
Application rates must be no higher than those set out in national published recommendations.
These fertiliser P rates take into account soil P and P in manures.

21. The Netherlands Response:
Question 2 Based on N surpluses for grassland in Table maximum phosphate surplus of 10 kg P2O5/ha/yr what are the expected concentrations in surficial groundwater and drainage water?
Response:
For Nitrate
Farm A
Farm B
Farm C
Non derogated
Derogated
Farm N surplus (kg N/ha/year)
296
337
302
Mean annual nitrate (mg NO3/L)*
28.5
33.0
29.2
* Assumes nitrate losses of 14% of surplus and runoff of 0.6 m /year.
For P the proposed P surplus is 10 kg P/ha/yr.
Increased river P associated with surplus P and increasing soil P.
Lowering P surplus from current 23 kg P/ha/yr to 10 kg P/ha/yr will lower annual increase in drainage from derogated farms from 4.0 to 1.7 mg P/L/year.
But lower P in drainage from derogated farms expected from Action Plan:
From manure - 63 mg P /L & from chemical P fertiliser mg P/L.
Equation in (kg N/ha/year) for estimating nitrate losses (y) from N surplus (x) is
y = x
Long-term annual P surplus of 16 kg P/ha for agriculture associated with increasing concentrations of dissolved reactive P to into Northern Ireland at a rate of 2.58 ± µg P/L/year. (A similar relationship has been established between the P surplus and increases in drainage P from grazed grassland.) Using this relationship, the surplus of 10 kg P/ha will cause underlying increase of 1.7 µg P/L/year in drainage water from the relevant farms. Current P surplus on derogated dairy farms estimated at 23 kg P/ha = current increase is 4.0 µg P/L/year
Less reductions in P losses from the current Nitrates Action Programme and Phosphorus Regulations.
Closed period from mid-October to the end of January reduces by 61% the days with a high risk of P loss from manure applications from October to March. On the basis that this reduction will lower current losses of manure P by a similar proportion from 3% to 1.2% of the P applied and a stored manure P application of 20.9 kg P/Ha/year, annual losses of P lowered by 0.38 kg P/ha or lower P concentrations in drainage water of 63 µgP/L.
Phosphorus Regulations should virtually eliminate applications of chemical P fertilisers on intensive grassland farms. On the basis that 0.5% of previous chemical fertiliser P applications were lost to water and current chemical P fertiliser rate for dairy Farm C of 15 kg P/ha/year cease, then annual P losses lowered by kg P/Ha, & concentrations of P in drainage by 12.5 µg P/L.

22. The Netherlands
Question 3 How do the N and P surpluses and resulting concentrations in surficial groundwater and drainage water relate to the concentrations that are expected to comply with the eutrophication surface water standards (Good Ecological Status) of the WFD?
Response:
Eutrophication standards for N and P concentrations have yet to be set for lakes and rivers in Northern Ireland, the UK or for the Republic of Ireland. (This is consistent with the timeline set for implementing the Water Framework Directive).

23. Sweden
Question 1 What is the reason for assuming usage of more chemical fertilisers and higher grass production than needed on farm A and B? Did you consider other levels of fertiliser or land usage?
Response:
A higher level of herbage production is produced relative to that required for Farms A and B. This reflects the lower stocking rate of Farm A and substitution of herbage by concentrates on Farm B.
If surplus grass is produced it will be conserved as silage and offered for sale .
Livestock farmers in Northern Ireland have limited opportunity to grow arable crops to replace grass and are more likely to increase purchase of imported feeds – increasing N and P input onto farm.

24. Belgium
Question 1 What is the ratio of N2O to N in the denitrification process and estimated effect of derogation on this ratio?
Response:
Upper and lower estimates of N2O emissions vary by a factor of 38 In the greenhouse gas inventory for Northern Ireland.
Given this uncertainty a definitive answer cannot be given to the question.
However, evolving practices for nitrogen management on farms, including measures contained in the Nitrates Action Programme Regulations, may result in lower denitrification losses.

25. Summary of potential management effects on N2O emissions
Factor influencing N2O emissions
Impact on N20
Apply more manure N in historic N management framework. 
But following likely changes in N management
Winter closed period  Higher soil temperature & lower soil moisture when manure is applied  Less denitrification. 
Better manure N efficiency  Less nitrate fertiliser  Lower soil nitrate  Less denitrification.
Increased lime use = >soils at target pH of 6.0  Lower N20 fraction.
> band spreading to increase N efficiency  lower interaction between chemical fertiliser N & slurry carbon  Less denitrification & lower N20 fraction
Apply nitrate fertiliser >4 days after manure  Less labile soil carbon for denitrification  Lower denitrification & N20 fraction
N2O is produced by nitrification, denitrification or dissimilatory NO3 reduction (DNRA). But in Northern Ireland the dominant source of both N2 and N2O in soils has been shown to be from the NO2 poll (i.e. from denitrification)
Grassland soil average pH 5.3. Current lime recommendation to maintain soil pH of 6.0 is , 000 tonnes /year. Current lime use to 2006 is 130,000 tonnes/year.
Potentially less interaction between fertiliser NO3 and slurry when slurry band spread as opposed to current splash plates. This should lower both denitrification and lower N2O fraction

26. Scientific Case for Derogation for Northern Ireland
Summary of
Scientific Case for Derogation for Northern Ireland
Primary land use is grassland
Excellent grass growing conditions
(yield potential t DM per ha)
High N uptake from grassland
High soil organic matter (and N content)
Soils with high denitrification ability
Efficient grass – based livestock systems
(UME output up to 135 GJ/ha
In addition a mandatory P balance on derogated farms will
ensure no detrimental effect on water quality