DIAS Nitrate leaching and pesticide use in energy crops Uffe Jørgensen, Danish Institute of Agricultural Sciences, Dep. of Agroecology, Research Centre Foulum

DIAS Biomass use and production in Denmark Total energy use 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 ha. willow

DIAS 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.

DIAS 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

DIAS Nitrate leaching from energy crops Measured by installation of suction cups below the root zone

DIAS Nitrate leaching from willow Coarse sand 150 kg N 105 kg N 3-9 kg N kg N 1-16 kg N

DIAS Nitrate leaching from miscanthus loamy sand

DIAS Leaching from common agricultural crops on sand PeasWinter barley Winter wheat Oats Winter barley Winter rape Winter wheat N leaching, kg per ha Concentration of nitrate-N Apr88Oct88Apr89Oct89Apr90Oct90Apr91Oct91Apr92Oct92Apr93Oct93Apr94

DIAS Protection of drinking water on the renewable energy island, Samsø

DIAS How much can nitrate leaching be reduced by changing to energy crop production? Energy crops substituteReduced 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

DIAS 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

DIAS Mechanical weed management

DIAS Annual pesticide treatments in energy crops Triticale ,9 (0,3 - 1,7) Triticale ,7 (0 - 0,9) Miscanthus Foulum, ,6 (0 - 3,0) Miscanthus Jyndevad, ,0 (0 - 5,9) Willow Foulum, Willow Jyndevad, ,4 (0 - 3,0) Mean in Danish agriculture2,2 Reduction target 20091,7

DIAS Energy crops can ensure water quality But what about quantity? Willow uses a lot of water! Soil water percolation from winter wheat willow mm404 mm mm537 mm mm0 mm

DIAS Miscanthus saves water Soil water content in willow and miscanthus

DIAS 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

DIAS Willow, poplar & alder

DIAS Miscanthus

DIAS Reed Canary grass