PHOSPHORUS USE AND RECYCLING

IN ORGANIC FARMING IN DENMARK

Margrethe Askegaard, M.Sc. Agric., PhD

mga@seges.dk, SEGES Organic farming

“Phosphorus a Limited Resource - Closing the Loop”, Malmø 28th October, 2016

SWOT ANALYSIS FOR THE USE OF URBAN

ORGANIC WASTES IN ORGANIC FARMING

2..

Strengths:

• Use of urban organic wastes

corresponds with the Danish

Resources Strategy for waste

management

• Promotes the EU target for increased

use of wastes and recirculation in

organic farming

Weaknesses:

• Challenges the organic

precautionary principle because

urban organic waste may include

toxic components.

Opportunities:

• Promotes conversion to organic

farming, especially in Eastdenmark

• Higher yields

• Elevated Danish production of feed

concentrates.

• Reduced carbon footprint

Threats:

• Negative consumer reactions to

meat and bone meal, or sewage

sludge or related residual products

• Detection of new problematic

elements in accepted waste

products

DO WE HAVE A PROBLEM WITH PHOSPHORUS

DEFICIENCY IN ORGANIC FARMING?

● We don’t know!

● Organic farmers focuses on N, K and S as yield limitingfactors – not P.

● The willingness to pay for P is relatively low.

● But we need to be much more aware of the P-supply to the soils, especially in the eastern part of Denmark.

● And organic agriculture need to get access to the availableP sources now – before they all flow in to streams addingforbidden substances.

3..

THE MAIN CHALLENGE:

4..

NS

KP

THE GEOGRAFIC DISTRIBUTION OF P-SURPLUS IN

DENMARK

5..

Vi har opsparet 1,4 ton P/ha,

men de er uens fordelt, og

så er jo også udfasningen

der ”truer”

2005 2013

Andersen et al. 2016. Redegørelse for udvikling i landbrugets fosforforbrug, tab og påvirkning af

vandmiljøet. Teknisk rapport fra DCE – Nationalt Center for Miljø og Energi

DIFFERENT P-STATUS IN EAST AND WEST

DENMARK

6..Olsen-P (Pt) intervals

0,0

- 0,9

1,0

- 1,9

2,0

- 2,9

3,0

- 3,9

4,0

- 4,9

5,0

- 5,9

6,0

- 6,9

7,0

- 7,9

8,0

- 8,9

9,0

- 10,

0

> 10

,0

Dis

trib

ution o

f soil

test analy

sis

(%

)

0

10

20

30

40

Sealand

Western Jutland

FARMGATE P-BALANCES 2007-2008

7..

Organic dairy farms

Livestock units ha-1

0,6 0,8 1,0 1,2 1,4 1,6 1,8

Surp

lus (

kg P

ha

-1)

-10

-5

0

5

10

15

20

25

30

NITROGEN AND PHOSPHORUS APPLICATION IN

ORGANIC FIELDS

8..

Extract from fertilizer accounts

2013/2014 for organic farms.

Include both own and

purchased organic fertilizers.

kg h

a-1

0

10

20

30

40

50

60

70

80

90

100

110

120

130

Total-N

NH4-N

P estimated

Sealand

Funen

Bornh

olm

Jutla

nd E

ast

Jutla

nd N

orth

Jutla

nd W

est

POTENTIAL PHOSPHORUS RESSOURCES

9..Ton P per yr.

0 1000 2000 3000 4000

Vinasse

Biomass cuts from streams

Roadside cuts

Food waste from retail and production

Protamylasse

Fertigro

Wood ash

Biomasses from natural areas

Green garden and park waste

Source separated food waste private households

Novogro

Meat and bone meal

Sewage sludge

Not permitted

Permitted

Permitted ( )

10..

Thank you for your attention