Rev. Bras. Ciênc. Solo.2012;36(6):1814-9.

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N₂O emissions from a cultivated mollisol: optimal time of day for sampling and the role of soil temperature

Vanina Rosa Noemi Cosentino, Patricia Lilia Fernandez, Santiago Andrés Figueiro Aureggi, Miguel Angel Taboada

01/Dec/2012

DOI: 10.1590/S0100-06832012000600015

The correct use of closed field chambers to determine N₂O emissions requires defining the time of day that best represents the daily mean N₂O flux. A short-term field experiment was carried out on a Mollisol soil, on which annual crops were grown under no-till management in the Pampa Ondulada of Argentina. The N₂O emission rates were measured every 3 h for three consecutive days. Fluxes ranged from 62.58 to 145.99 ∝g N-N₂O m^-2 h^-1 (average of five field chambers) and were negatively related (R² = 0.34, p < 0.01) to topsoil temperature (14 – 20 ºC). N₂O emission rates measured between 9:00 and 12:00 am presented a high relationship to daily mean N₂O flux (R² = 0.87, p < 0.01), showing that, in the study region, sampling in the mornings is preferable for GHG.