dias nitrate leaching and pesticide use in energy crops uffe jørgensen, danish institute of...
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DIAS
Nitrate leaching and pesticide use in energy crops
Uffe Jørgensen, Danish Institute of Agricultural Sciences,
Dep. of Agroecology, Research Centre Foulum
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Biomass use and production in Denmark
• Total energy use 2004 839 PJ• Biomass (straw, wood, biogas) 59 PJ• Municipal waste 37 PJ• Wind power 24 PJ
Renewable energy 14% of total energy use
Energy crops:• 10-20,000 ha. rape & c. 1000 ha. willow
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Danish agriculture can produce much more energy – but also have to fulfil …
• The Water Framework Directive• The Ground Water Directive• The Habitat Directive• The 3rd national action plan on the
aquatic environment• The national action plan on pesticides• Etc.
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Annual versus perennial crops
• Perennial crops have the most efficient nutrient use
• Perennial crops are hardy and competitive (not during establishment)
• Therefore, perennial crops are more easy to produce with low environmental impacts
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Nitrate leaching from energy crops
•Measured by installation of suction cups below the root zone
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Nitrate leaching from willow Coarse sand
0
10
20
30
40
50
60
70
80
90
100
jul
93
jan
94
jul
94
jan
95
jul
95
jan
96
jul
96
jan
97
jul
97
jan
98
jul
98
jan
99
jul
99
jan
00
mg
nit
rate
-N/li
tre
0 N
75 N
sludge with c. 140 N
sludge with c. 280 N
drinking water quality
150 kg N
105 kg N
3-9 kg N
13-42 kg N
1-16 kg N
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Nitrate leaching from miscanthus loamy sand
0
20
40
60
jul 9
3
jan
94
jul 9
4
jan
95
jul 9
5
jan
96
jul 9
6
jan
97
jul 9
7
jan
98
jul 9
8
jan
99
jul 9
9
jan
00
mg
NO
3-N
/lit
re s
oil
wa
ter 0 N
75 N
140 N slurry
280 N slurry
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Leaching from common agricultural crops on sand
Peas Winterbarley
Winterwheat
Oats Winterbarley
Winterrape
Winterwheat
100
80
60
40
20
0
20
40
60
80
100
120
140
160
180
200
220
100
80
60
40
20
0
20
40
60
80
100
120
140
160
180
200
220
N leaching, kg per haConcentration of nitrate-N
Apr88 Oct88 Apr89 Oct89 Apr90 Oct90 Apr91 Oct91 Apr92 Oct92 Apr93 Oct93 Apr94
DIAS 0
25
50
75
100
125
150
175
200
01-09-2001
01-12-2001
01-03-2002
01-06-2002
01-09-2002
01-12-2002
01-03-2003
01-06-2003
01-09-2003
01-12-2003
01-03-2004
01-06-2004
01-09-2004
01-12-2004
01-03-2005
01-06-2005
01-09-2005
01-12-2005
mg
nit
rate
/litr
e
crop rotation
miscanthus
mis. environmentally optimised
potatoes / ryegrass / spring barley + ryegrass /potatoes / oats+ryegrass /potatoes/persian clover+fodder radish/ white cabbage 118 kg N/ha 109 kg N/ha 69 kg N/ha 35 kg N/ha 168 kg N/ha
Protection of drinking water on the renewable energy island, Samsø
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How much can nitrate leaching be reduced by changing to energy crop
production?
Energy crops substitute Reduced leaching c.
Crop rotation: 50 kg N/ha.Annual set aside: 30 kg N/ha.Grass fallow: -10 kg N/ha.
• Mean N-abatement cost in the latest national action plan for the aquatic environment: 21 DKK per kg N
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Pesticide use in energy crops
• Quality demands not so crucial for
energy use
• Hardy and competitive crops
• Weed management is important
during establishment of
perennial crops
• Pesticide-free production possible
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Mechanical weed management
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Annual pesticide treatments in energy crops
• Triticale 1997-98 0,9 (0,3 - 1,7)• Triticale 1998-99 0,7 (0 - 0,9)
• Miscanthus Foulum, 1993-2000 0,6 (0 - 3,0)• Miscanthus Jyndevad, 1993-2000 1,0 (0 - 5,9)
• Willow Foulum, 1993-2000 0• Willow Jyndevad, 1993-2000 0,4 (0 - 3,0)
• Mean in Danish agriculture 2,2• Reduction target 2009 1,7
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Energy crops can ensure water qualityBut what about quantity?
Willow uses a lot of water!
Soil water percolation from
winter wheat willow
1993-94 522 mm 404 mm
1994-95 648 mm 537 mm
1995-96 77 mm 0 mm
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Miscanthus saves water
Soil water content in willow and miscanthus
10
15
20
25
30
35
01-mar 01-apr 01-maj 01-jun 01-jul 01-aug 01-sep 01-okt 01-nov 01-dec 01-jan
% v
an
d (
0 -
50
cm
)
Elefantgræs (miscanthus)
Pil (willow)
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Conclusions
• Energy crops and good water quality can be co-produced
• Perennial energy crops reduce nitrate leaching– by up to 50 kg N/ha
– especially efficient in utilising manure and sludge
• Compared with fallow and afforestation energy crop production secures continued animal production
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Willow, poplar & alder
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Miscanthus
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Reed Canary grass