Nitrate leaching losses under Miscanthus grass planted on a silty clay loam soil

Nitrate leaching under newly planted Miscanthus grass was measured for three years. The crop received either no fertilizer-N or an annual spring application of 60 kg or 120 kg N ha(-1). During three winters soil water was collected from porous cup probes installed 90 cm deep. Nitrate leaching was calculated from the mean drain flow recorded in tao drain gauges multiplied by the mean nitrate-N concentration in the soil water solutions collected. In the first year soil water nitrate concentrations were high on all treatments and N losses were 154, 187 and 228 kg ha(-1) respectively on the unfertilized treatment and those that received 60 or 120 kg N ha(-1). Leaching losses in the second and third years were, in turn, 8, 24 and 87 kg ha(-1) and 3, 11 and 30 kg ha(-1) for the unfertilized treatment and for the 60 and 120 kg N ha(-1) treatments respectively Leaching losses were closer to those recorded under extensively managed grassland than arable land. The large losses in the first year were probably due to the previous agricultural management at the site and excessive inputs of N on the fertilized plots. In the second and third year, lower drainage volumes may also have influenced losses. The results show that Mis canthus, once established, can lead to low levels of nitrate leaching and improved groundwater quality; compared with growing arable crops.