Influence of Watering Methods on the Short-Term Pulse Emissions of Nitrous Oxide from Disturbed Horticultural Soil

To reveal the impact of soil disturbance and surface watering (SW) following soil disturbance on the pulse nitrous oxide (N2O) emissions, incubated experiments were conducted on disturbed soil with two watering regimes [surface watering only (SWO) and subsurface watering followed by surface watering (SUW+SW)]. Intensive soil disturbance led to pulses N2O emissions from SUW + SW soil (>8,693 g N2O m(-2) h(-1) with a peak of 30,938 g N2O m(-2) h(-1)), although the water-filled pore space (WFPS) was substantially lower than the previously reported optimal soil moisture range (45-75% WFPS) for peak N2O emissions. N2O emissions from the disturbed soil after SW were much lower than those from SUW + SW soil, increased as the soil dried, and peaked when the WFPS fell within the optimal soil moisture range. These peaks were considerably less than those resulting from the intensive disturbance in SUW + SW soil. Thus, SW after intensive soil disturbance may be effective for mitigating of pulse N2O emissions caused by soil disturbance.