Effect of fertilizer application on ammonia emission and concentration levels of ammonium, nitrate, and nitrite ions in a rice field

The concentrations of ammonium (NH4+), nitrate (NO3-), and nitrite (NO2-) ions were recorded along with ammonia (NH3) emission from a fertilized rice field located in the Kwangju province in South Korea over a period of 4 months (June to October 2006). The highest magnitude of NH3 flux was 20,754 mu g m(-2) h(-1), while the average flux value over the entire sampling period was 2,395 mu g m(-2) h(-1). The highest ionic concentrations were 1.67, 0.44, and 0.71 ppm for NH4+, NO3-, and NO2- ions, respectively. Possible effects of soil pH on NH3 fluxes were detected, as they concurrently exhibited a gradual and periodic change during the sampling period. Positive correlations existed between concentrations of NH4+ and NO2- ions and the soil pH. Positive correlations also existed between NH3 emission flux and ambient (and water) temperatures. Results indicated that fertilizer application to rice can lead to significant emission of NH3 along with NH4+ and NO3- ions.