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 ug N-N2O m-2 h-1 (average of five field chambers) and were negatively related (R2 equal 0.34, p less than 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 equal 0.87, p less than 0.01), showing that, in the study region, sampling in the mornings is preferable for GHG.
Cosentino, V. R. N., Fernández, P. L., Aureggi, S. A. F., & Taboada, M. A. (2012). N2o emissions from a cultivated Mollisol : optimal time of day for sampling and the role of soil temperature. Revista Brasileira de Ciencia do Solo,36, (6),p.1814-1819
10.1590/S0100-06832012000600015
Cosentino, Vanina Rosa Noemí, Fernández, Patricia Lilia, Aureggi, Santiago Andrés Figueiro, Taboada, Miguel Angel. 2012. "N2o emissions from a cultivated Mollisol : optimal time of day for sampling and the role of soil temperature". Revista Brasileira de Ciencia do Solo 36, no.6:1814-1819.
Recuperado de http://ri.agro.uba.ar/greenstone3/library/collection/arti/document/2012Cosentino