Drainage, cattle excreta and trampling effects on nitrous oxide emissions from a peat grassland

To mitigate the effects of drainage on carbon dioxide emissions and soil subsidence from grasslands on peat soils, measures are explored to raise groundwater levels or reduce groundwater level fluctuations, such as the implementation of a water infiltration system. The effect of water infiltration systems on nitrous oxide emissions from peat grasslands has not received much attention yet. On peat grasslands, nitrous oxide emissions can be intensified by cattle grazing through the input of nitrogen in urine and dung, as well as soil compaction caused by trampling. Therefore, the combined effects of a water infiltration system and simulated grazing on nitrous oxide emissions from a peat grassland were studied in a two-year field experiment. Without nitrogen inputs, cumulative nitrous oxide emissions from peat oxidation were lower, but not significantly, under a water infiltration system compared to conventional drainage (1.2 ± 0.25 kg N ha −1 vs 8.8 ± 3.7 kg N ha −1 ). Urine, dung and trampling application all significantly increased cumulative nitrous oxide emissions in both drainage systems. There was a significant interaction effect between drainage type and urine application, indicating different effects of water infiltration systems in the absence or presence of urine application. Urine and dung emission factors were higher under a water infiltration system than conventional ditch drainage. These results suggest that water infiltration system effects on nitrous oxide emissions from peat grasslands are not consistent, and interact with external nitrogen inputs through cattle grazing. • Urine, dung and trampling increased N 2 O emissions from peat grasslands. • N 2 O emissions lower under a water infiltration system than conventional drainage. • Limited effect of water infiltration system on N 2 O from urine derived nitrogen. • Higher urine and dung emission factors under a water infiltration system.