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How to half N-losses, improve N-efficiencies and maintain yields? The Danish Case

By Tommy Dalgaard (tommy.dalgaard@agrsci.dk), C.D. Børgesen, J.F. Hansen, N.J. Hutchings, U. Jørgensen and A. Kyllingsbæk.

Danish Institute of Agricultural Sciences. Department of Agroecology.

Plantekongres 2006. Session T96: Tools for reducing N-losses. Can we fulfil the WFD?

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Programme

• Agriculture & Environmental problems __in Denmark

• Developments in the N balance

• N-yields versus N-losses

• Catalogue of statutory measures to __ improve N-management

_- How half N-losses and maintain yields?

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Intensive agriculture in Denmark

• 2,7 mio ha agricultural land (63% of total area)

• 5 mio people - 4,5 mio t milk - 24 mio pigs/yr

• 8 t milk/cow/yr

• 24 piglets/sow/yr

•7,5 t wheat/ha/yr

• 7500 km coastline

• Drinking water = groundwater

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Dairy Cows Pigs Wheat (1000’s) (1000’s) (1000 ha)

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The nitrogen balance

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Development phases

N-imports N-exports

0

20

40

60

80

100

120

140

160

180

200

1900 1920 1940 1960 1980 2000

year

index

N-fertiliser import

Fodder import

From the atmosphere

-50

0

50

100

150

200

1900 1920 1940 1960 1980 2000

year

index

Vegetable exports Animal exports

NB: year 2000= index 100

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I: Traditional livestock farming (1900-1950)

0

20

40

60

80

100

120

140

160

180

200

1900 1920 1940 1960 1980 2000

year

index

N-fertiliser import

Fodder import

From the atmosphere

-50

0

50

100

150

200

1900 1920 1940 1960 1980 2000

year

index

Vegetable exports Animal exports

NB: year 2000= index 100

I I

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II: The green revolution (1950-1983)

0

20

40

60

80

100

120

140

160

180

200

1900 1920 1940 1960 1980 2000

year

index

N-fertiliser import

Fodder import

From the atmosphere

-50

0

50

100

150

200

1900 1920 1940 1960 1980 2000

year

index

Vegetable exports Animal exports

NB: year 2000= index 100

I II I II

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III: Sustainable development (1984-?)

0

20

40

60

80

100

120

140

160

180

200

1900 1920 1940 1960 1980 2000

year

index

N-fertiliser import

Fodder import

From the atmosphere

-50

0

50

100

150

200

1900 1920 1940 1960 1980 2000

year

index

Vegetable exports Animal exports

NB: year 2000= index 100

I II III I II III

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N-exports and crop yields

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N-surplus, N-leaching and N-efficiency

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Distribution of simulated N-leaching

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Action plans to reduce N-losses

• 1985: Action plan to reduce N- and P-pollution

• 1987: First action plan for the aquatic environment (AP-I)

(Aim: half N-losses and reduce P-losses by 80%)

• 1991: Action plan for sustainable agriculture

• 1998: Second Action Plan (AP-II)

• 2000: AP-II midterm evaluation and enforcement

• 2001: Ammonia Action Plan

• 2004: Third Action Plan (AP-III)

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The 1985 Action Plan

Max. stock density of 2 LU ha-1 (1 LU corresponds to one large dairy cow or 30 porkers produced)

Minimum 6 months slurry storage capacity Ban on slurry spreading between harvest and

Oct 15 on soil destined for spring cropping Various measures to reduce runoff from silage

clamps and manure heaps Mandatory floating barriers on slurry tanks

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AP-I for the Aquatic Environment

Min. 9 months slurry storage capacity Mandatory fertiliser and crop rotation plans Minimum proportion of area to be planted with

winter crops Mandatory incorporation of manure within 12

hours of spreading

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Action Plan for Sust. Agriculture

Ban on slurry spreading from harvest until 1 Feb., except on grass and winter rape

Maximum limits on the plant-available N applied to different crops, equal to the economic optimum

Statutory norms for the proportion of manure N assumed to be plant-available

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AP-II for the Aquatic Environment

Enforced statutory manure N-norms Max application of N to crops reduced to 10% below

the economic optimum Red. of max. stock density to 1.7 LU ha-1 6% of the rotational area to be planted with catch crops. N retained by catch crops must be incl. in fertiliser plans Expectation that animal feeding practice will be

improved to reduce N excretion Subsidies to convert to organic farming Subsidies to establish wetlands Subsidies to reduced N inputs in sensitive areas Subsidies to afforestation

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Ammonia Action Plan

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AP-III for the Aquatic Environment

Enforced statutory manure N-norms Improved utilisation of N and P in feed A tax of DKK 4 kg-1. mineral P in feed Establishment of buffer zones along streams and around

lakes to reduce discharge of P Protection zones of 300 m around ammonia sensitive

habitats Request for more catch crops Strengthening of organic farming regulations Further wetland areas Further afforestation

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Summary

Improved N-management via:

• Mandatory fertilisation accounts

• Norms for fertilisation of crops

• Subsidies for new manure equipment and __environmental friedly practices

• Extensive research, demonstration and __ advisory programmes

• Better utilisation of manures

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Norms for manure N-utilisation

% plant available N in manures

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Conclusion

The regulations have been succesfull and might serve as inspiration for other countries

• N-leaching almost halved from 1985-2004

• Livestock production increased by 30%

• N crop yields sustained

Still posibilities and environmental needs for improvements.

Better methods for regionalised assessments needed for the implementation of the WFD