2. Danish Agricultural Advisory Service National Centre Nitrogen Input Control on Danish farms Senioradviser Leif Knudsen Danish Agricultural Advisory Service

3. Danish Agricultural Advisory Service National Centre Outline: Background for regulation of nitrogen input Review of the legislation The current legislation The effect of the legislation on farmers’ practice The economic consequences for the farmers The effect on environmental parameters

4. Danish Agricultural Advisory Service National Centre Two main problems caused by leaching of nitrogen from agriculture: Increase of nitrate in ground water /drinking water Incidences of depletion of nitrogen in the marine water (inlets, eustaries)

5. Danish Agricultural Advisory Service National Centre mineral fertilizer,kg/ha mg nitrate pr. liter Fertiliser Nitrate

6. Depletion of oxygen has always occured. Depletion of oxygen is more common with high N and P content. Depletion of oxygen was more common in the 80’ies and 90’ies than before. Eutrofication in inletsCover on buttom after an incident of lack of oxygen

7. Danish Agricultural Advisory Service National Centre TimePlanSignificant elements in legislation: 1985NPO-plan-regulation of allowed animal unit per ha. - min. storage capacity for animal manure 1987Water Environm. Plan I -50 pct reduction in N-leaching from agr. -65 pct ”autumngreen fields” -Slurry in autumn only to wintercovered fields 1992Sustain- able agri- culture -Slurry only to grass or oilseed rape in autumn -Max. N-standards for crops (N-quota per farm) -Min. utilization of nitrogen in animal manure -Fertilizer plans and -accounts. 1998Water Environm. Plan II -10 pct decrease of N-standards (The N-quota) - 6 percent ”super” green fields in autumn -15 pct higher utilization of N in animal manure

8. Danish Agricultural Advisory Service National Centre Maximum allowed animals per hectare Animal CategoryAnimal unit per ha Number of animals per ha Dairy cows *11,7/2,31,4/2,0 Sows1,46,0 Piglets 7,5-30 kg1,4245 Pigs, 30-102 kg1,450 Hens1,4289 Chickens1,44930 *1 without heifers 1 Animal Unít = 100 kg N ab storage

9. Danish Agricultural Advisory Service National Centre Storage capacity for animal manure Normal: At least 9 months on pig farms. 7 months on dairy farms with animals gra- zing in summer New stables: farmers normally invest for 12 months storage capacity

10. Danish Agricultural Advisory Service National Centre Animal manure continued Cover of liquid manure: Natural crust is enough but control is intensified by the authorities. If not in order there must be a solid cover (e.g. concrete, tent) Spreading time From harvest to 1st of February spreading of liquid manure is banned except: -on winter oilseed rape from harvest to 1 st of October -on grassland (overwintering) until 1 st October -On grass for seed until 15. October

11. Danish Agricultural Advisory Service National Centre Animal manure continued: Spreading technique: Use of broadcasting is banned. All liquid manure must be spread with trailing hoses or direct injection Manure spread on bare soil must be incorporated within 6 hours

12. Danish Agricultural Advisory Service National Centre Covercrops: 65 percent of the area must be ”Autumn Green fields: Wintercereal, winteroilseed rape, beets, potatoes(late), corn… 6 percent of the area must be ”supergreen Fields: catchcrops of undersown grass or crusifer crops.

13. Danish Agricultural Advisory Service National Centre Nitrogen quotas per farm: Nitrogen quota for each crop +/- Correction for yearly N-prognosis - Effect of catchcrops from last year - Minimum utilization of animal manure = Nitrogen quota in mineral fertiliser for the farm

14. Danish Agricultural Advisory Service National Centre Coarse sandLoam(15-25 percent clay) CropYield tonnes /ha Kg N/ha Yield tonne s/ha Kg N/ha Winterwheat after cereals5,01548,5171 Winterwheat after wi.rape5,61249,3155 Spring barley after cereal4,01186,1128 Spring barley after clovergrass 4,4586,768 Examples of Danish N-quotas for different crops

15. Danish Agricultural Advisory Service National Centre Minimum demands for utilization of total N in manure, % Pig slurry75 Cattle slurry70 Solid manure + urine65 Deep litter45 Sewage sludge45

16. Danish Agricultural Advisory Service National Centre Table 6. Example of a calculation of an N-quota for a pig farmer. Example of a quota for a pig farmer 50 haWinterwheat after cereals 167 kg N/ha8350 25 haSpring Barley104 kg N/ha2600 25 haSugar Beet107 kg N/ha2675 100 haTotal N-quota for the crops13625 5000 pigs produced with 26,7 kg N per 10 prod. 13.350 kg N produced in total x 75 pct. utilization 10013 Total N-quota left for N in mineral fertiliser3613

17. Danish Agricultural Advisory Service National Centre 0 50 100 150 200 250 300 350 400 450 198019851990199520002005 Thous. ton Nitrogen Mineral N N in animal manure

18. Danish Agricultural Advisory Service National Centre 0 100 200 300 400 500 600 19001925195019752000 1000 tons N Nitrogen surplus in Danish agriculture

19. Danish Agricultural Advisory Service National Centre Time for application of organic manure Slurry

20. Danish Agricultural Advisory Service National Centre Winter crop coverage

21. Danish Agricultural Advisory Service National Centre 0 50 100 150 200 250 300 350 400 450 500 198519901996199719981999 1000 ton N Misc. Change in soil content N-evaporation Denitrificatron Leaching N surplus in fields in DK

22. Danish Agricultural Advisory Service National Centre Development in N-concentration 1990/91 – 1998/99

23. Danish Agricultural Advisory Service National Centre Modelling of N-leaching in 7 catchments N-leaching at standard precipixation

24. Danish Agricultural Advisory Service National Centre Review of the legislation Year and actionRegulation: 1985: NPOStorage capacity, Max. allowed animal per ha. 1987: WEPP I65 pct. Wintercovered fields, storage capacity 1992:Sustainable Agriculture Max. N-quotas, banned autum applied liquid manure, fertiliser accounts. Minimum utilization of animal manure 1998: WEPP II10 percent reduction of N-quotas, 6 pct. additional catch crops 2004: WEPP III????

25. Danish Agricultural Advisory Service National Centre Nitrogen and phosphorus in artificial fertiliser 1990-2002 0 20 40 60 80 100 120 Denmark Sweden Finland Germany Holland Belgium-Lux. Great Britain Ireland France Austria Italy Spain Portugal Greece EU Rel. development 1989 to 2002 Nitrogen Phosphorus

26. Danish Agricultural Advisory Service National Centre Phosphorus surplus -10 0 10 20 30 40 50 60 70 80 90 1900192519501975 2000 1000 tons P