26 May, 2016 Panevėžys, Lithuania AGRICULTURAL DRAINAGE AND WATER QUALITY the demand for alternative practices to achieve the balance Arvydas Povilaitis "Water Management in Agriculture and Environment" 26 May, 2016 Panevėžys, Lithuania

Tile Drained Agricultural Land

Nutrient losses Nitrate-N 3-20 mg/l from tile-drained fields Total P concentrations: from 0.1 to 0.15 mg/l Annual Losses: - from 3 to 40 kg N/ha - 0.05-0.40 kg P/ha

Drainage runoff Air temperature °C Drainage runoff mm Miseckaitė, 2011

Golden rule of drainage „Drain only what is necessary for good trafficability and crop growth – and not a drop more” – any drainage in excess of this rule likely carries away nitrate and water that is no longer available for crop uptake.

Conservation Drainage Management practices that reduce nutrient transport from drained land and not reduce drainage performance: Controlled drainage Woodchip bioreactors Saturated riparian buffer strips Alternative open ditch design

Controlled drainage subirrigation Effect: - Reduced drainage outflow - Increased water retention time - Increased N uptake by crops - Denitrification NO3-N reduction – 20-50 (30)%

DENITRIFICATION BIOREACTORS Woodchips bioreactors The bioreactor consists of a trench filled with carbon source (woodchips) through which the drainage water is allowed to flow Wood chips

Denitrifying Bioreactor

Denitrifying Bioreactor Bioreactor‘s designed volume Organic load properties Microbiological activity N2O, NO gas emissions Longetivity Environmental impact Costs for Installation and maintenance

Laboratory scale tests

Laboratory scale tests