Danish efforts to reduce P loss from agriculture to the aquatic environment
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Transcript of Danish efforts to reduce P loss from agriculture to the aquatic environment
Dan
mar
ks J
ordb
rugs
For
skni
ngM
inis
terie
t for
Fø
deva
rer,
Lan
dbru
g og
Fis
keri
Danish efforts to reduce P loss from agriculture to the aquatic
environmentGitte Rubæk
Danish Institute of Agricultural Sciences
DJF
The P surplus in Danish AgricultureP
im
po
rt (
1000
to
nn
es)
(Kyllingsbæk, 2005)
P s
urp
lus
(Kg
P h
a-1)
Imported animal feed
Waste products
Mineral fertilizers
DJF
-5
0
5
10
15
20
25
30
35
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
kg f
osfo
r pe
r ha
P o
vers
kud
(kg
P /
ha
)The P surplus in danish agriculture
1,4 tonnes P ha-1 has accumulated in on agricultural
landTotal P (mg P/kg jord)
De
pth
(cm
)
Agricult.
Forest
DJF
Geographic distribution of the P surplus
(Dalgård et al., 2004)
P surplus in 2001(kg ha-1 agricultural land)
DJF
Very high spatial variability in P losses from land
Source
område medhøjt indhold af
flytbartfosfor
Areas with a high content of potentially mobile P
Transport
med højttransport-potentiale
områdeAreas with a high potential for P transport
Critical source area
DJF
P losses in landscape
Stream
Cultivated land(source area)
Soil erosion
Surface run-off
Meadows, occasionally flooded(P deposition)
Leaching and potential lossthrough drainage system
Stream Banks(source)
Buffer Zone(P deposition)
2 m uncultivated zone(Law enforced)
Drained low-land soil (Source area)
DJF
P discharge to coastal waters in DK
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
spildevand +spredt bebyggelse
industri
dambrug
gårdbidrag
dyrket areal
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 20001900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
spildevand +spredt bebyggelse
industri
dambrug
gårdbidrag
dyrket areal
(after Rüegg og Østergaard, 2002)
Waste water
Industry
Fish hatchery
Farm contribution
Diffuse losses, cropped land
DJF
P loss from farmland to surface watersin DK - estimatesCertainty of estimate: (+) = Incufficient; (+++) = average; (+++++) = high
Total P (tonnes year-1)Erosion-related losses 287 - 695• Water erosion (++) 7 - 35• Stream bank erosion (++) 275 - 645• Wind erosion (+) 5 – 15
Drainage related leaching, total 65 - 405• Leaching from high risk areas (mineral soils) (+) 15 - 90• Leaching from other areas (mineral) (+++) 20 - 90• Leaching from lowland organic soils (+) 30 – 225
Groundwater related leaching, total 125 - 210• Leaching to shallow ground water (++) 80• Leaching to deeper ground water(++) 45 – 130
Atmospheric deposition (++++) < 5
SUM (without leaching to deep ground water) 440 - 1180
Kronvang & Rubæk, 2005
DJF
“Experts” conclusions during the preparations for VMPIII
A dual strategy combining:
• General measures to reduce the P surplus and optimizing P distribution on farmland– Improved feeding (Digestibility, phytase
additions, reduced safety margins based on improved knowledge of physiological need)
• Targeted measures to reduce P losses from high-risk areas (critical source areas)
Poulsen and Rubæk, 2005, DIAS report nr 68
DJF
The Danish Action Plans (Vand-Miljø-Planer)
• VMP-I and VMP-II had focus on:– N emissions from agriculture– P emissions from point sources
• The VMPIII addresses:– The P surplus in agriculture– The P losses from farmland– …and N leaching, vulnerable nature,
organic farming and a “slurry action plan”
DJF
The political agreement on P in VMPIII
• 50% reduction in the annual P surplus– tax on feed-phosphates– improved utilization of animal feed P
• Buffer zones along streams and lakes– volunteer subsidized agreements (MVJ)– 10 meter zones, 50.000 ha
• Research and development…..
DJF
P related research and development in VMPIII
• Reducing the P surplus – P utilization in animal husbandry – Slurry treatment - including combustion
• “Land management”– A Danish P index– Management of Stream Banks, Buffer zones, Flood
plains and low land – Management on farmland– Modeling P effects in estuaries– Cost and benefits of mitigation strategies– A web-based interactive tool for N and P
management of watersheds
DJF
Land management research projects
Mapping layers, mapping
techniques
Modeling P effects in estuaries
Management of buffer zones, stream banks, floodplains and
lowlands
Costs and Benefits of
mitigation strategies
Interactive web-based
tool for nutrient management
A Danish P index
Management on farmland
DJF
Silkeborg, 3-7 sep 2007