Wednesday, November 15, 2006

Nitrous oxide gas exchange between the atmosphere and a grassfield applied with dairy cattle manure.

Kosuke Noborio1, Naoya Satta2, Masaaki Sato3, Ieyasu Tokumoto1, and Kiyoshi Koga2. (1) Meiji University, School of Agriculture, 1-1-1 Higashimita, Tama-ku, Kawasaki, 214-8571, Japan, (2) Iwate University, Faculty of Agriculture, Morioka, Japan, (3) Hokkaido University, Graduate School, Sapporo, Japan

It is reported that the origin of nitrous oxide gas emitted into the atmosphere is largely attributed to agriculture.  We investigated nitrous oxide gas emission from an Andisol grassfield, in northeastern Japan, applied with dairy cattle manure.  The conditional sampling method was used to continuously measure gas flux in the experimental field.  Air samples carried by updraft and downdraft winds were separately stored and analyzed every 5 min using a photoacoustic field gas-monitor.  In addition the standard closed chamber method was used as well.  Gas samples in the chamber were collected every 15 min and analyzed using a gas chromatograph equipped with an electron capture detector.  Nitrous oxide gas fluxes measured with both methods were found to be comparable.  A large spike of nitrous oxide gas flux into the atmosphere was detected approximately a week after a manure application.  During a snow-accumulated season, nitrous oxide gas flux into the atmosphere was evident using both methods.  Nitrous oxide gas flux into the grassland from the atmosphere was also detected using the conditional sampling method.  Nitrous oxide gas exchange between the atmosphere and the land should be addressed in the future research to properly assess the effect of agriculture on the net emission of the greenhouse gases.

Handout (.pdf format, 72.0 kb)